We have entered into an At-the-Market Equity Offering Sales Agreement with Stifel, Nicolaus & Company, Incorporated (“Stifel” or the “Sales Agent”), dated September 28, 2022 (the “ATM Sales Agreement”), relating to the sale of shares of our Class A common stock (“Class A Stock”) offered by this prospectus supplement and the accompanying prospectus. In accordance with the terms of the ATM Sales Agreement, under this prospectus supplement and accompanying prospectus we may offer and sell up to $50,000,000 of shares of our Class A Stock from time to time through the Sales Agent, acting as agent.

Sales of our Class A Stock, if any, under this prospectus supplement and the accompanying prospectus will be made by any method permitted that is deemed an “at the market offering” as defined in Rule 415 under the Securities Act of 1933, as amended, or the Securities Act. The Sales Agent is not required to sell any specific amount, but will act as our sales agent using commercially reasonable efforts consistent with its normal trading and sales practices. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The Sales Agent will be entitled to compensation at a commission rate of up to 3.0% of the gross sales price per share sold. In connection with the sale of the Class A Stock on our behalf, the Sales Agent will be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation of the Sales Agent will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contribution to the Sales Agent with respect to certain liabilities, including liabilities under the Securities Act.

Our Class A Stock is listed on the Nasdaq Global Select Market under the symbol “MNTS.” On September 27, 2022, the last reported sales price of our Class A Stock was $1.40 per share.

We are an “emerging growth company” as defined in Section 2(a) of the Securities Act of 1933, as amended, and, as such, have elected to comply with certain reduced disclosure and regulatory requirements.

Investing in our securities involves risks. In reviewing this prospectus supplement, you should carefully review the risks and uncertainties referenced in the section of this prospectus supplement entitled “Risk Factors” and in the other documents that are incorporated by reference into this prospectus supplement before you consider buying our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

This prospectus supplement and the accompanying prospectus relate to the offering of our Class A Stock. Before buying any of the Class A Stock that we are offering, you should carefully read this prospectus supplement, the accompanying prospectus, the information and documents incorporated herein by reference and the additional information under the heading “Where You Can Find More Information” and “Information Incorporated by Reference.” These documents contain important information that you should consider when making your investment decision.

This prospectus supplement and the accompanying prospectus are part of a registration statement on Form S-3 (File No. 333-267230) that we filed with the U.S. Securities and Exchange Commission (the “SEC”) on September 1, 2022. Under this shelf registration process, we may, from time to time, offer Class A Stock, preferred stock, debt securities, unit and rights and warrants to purchase Class A Stock, preferred stock and debt securities, of which this offering is a part.

This document is in two parts. The first part is this prospectus supplement, which describes the terms of this offering of Class A Stock and also adds, updates and changes information contained in the accompanying prospectus and the documents incorporated herein by reference. The second part is the accompanying prospectus, which provides more general information about our Class A Stock and other securities that do not pertain to this offering of Class A Stock. If information in this prospectus supplement is inconsistent with the accompanying prospectus, you should rely on this prospectus supplement. To the extent there is a conflict between the information contained in this prospectus supplement, on the one hand, and the information contained in any document incorporated by reference in this prospectus supplement, on the other hand, you should rely on the information in this prospectus supplement. If any statement in one of these documents is inconsistent with a statement in another document having a later date – for example, a document incorporated by reference into this prospectus supplement – the statement in the document having the later date modifies or supersedes the earlier statement. Please also see “About this Prospectus” in the accompanying prospectus for further cautionary information regarding the use of this prospectus supplement and the accompanying prospectus.

We and the Sales Agent are offering to sell, and seeking offers to buy, shares of our Class A Stock only in jurisdictions where offers and sales are permitted. The distribution of this prospectus and the offering of the Class A Stock in certain jurisdictions may be restricted by law. Persons outside the United States who come into possession of this prospectus must inform themselves about, and observe any restrictions relating to, the offering of the Class A Stock and the distribution of this prospectus outside the United States. This prospectus does not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

References in this prospectus supplement to “Momentus,” “we,” “us,” “our,” or “the Company” mean Momentus Inc., a corporation formed under the laws of the State of Delaware, and its consolidated subsidiaries, unless we state otherwise or the context indicates otherwise.

This prospectus supplement and the accompanying prospectus incorporate by reference important business and financial information about the Company that is not included in or delivered with such documents. The information incorporated by reference is considered to be part of this prospectus supplement, and the SEC allows us to “incorporate by reference” the information we file with it, which means that we can disclose important information to you by referring you to those documents instead of having to repeat the information in this prospectus supplement. Any statement contained in any document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained in or omitted from this prospectus supplement and the accompanying prospectus, or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein, modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement. We incorporate by reference:

All documents filed by the Company pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act after the date of this prospectus supplement and prior to the filing of a post-effective amendment which indicates that all securities offered hereby have been sold or which deregisters all securities then remaining unsold shall be deemed to be incorporated by reference into this prospectus supplement and to be a part hereof from the date of filing of such documents; provided, however, that documents or information deemed to have been furnished, and exhibits furnished in connection with such items, and not filed in accordance with the rules of the SEC shall not be deemed incorporated by reference into this prospectus supplement.

We have filed with the SEC a registration statement under the Securities Act of 1933, as amended (the “Securities Act”), covering the securities to be offered and sold by this prospectus supplement and the accompanying prospectus. This prospectus supplement does not contain all of the information included in the registration statement, some of which is contained in exhibits to the registration statement. The registration statement, including the exhibits thereto, can be read at the SEC website referred to below under “Where You Can Find More Information.” Any statement made in this prospectus supplement concerning the contents of any contract, agreement or other document is only a summary of the actual contract, agreement or other document. If we have filed any contract, document, agreement or other document as an exhibit to the registration statement or any other document incorporated herein by reference, you should read the exhibit for a more complete understanding of the document or matter involved. Each statement regarding a contract, agreement or other document is qualified in its entirety by reference to the actual document.

Our filings with the SEC, including Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and amendments to those reports, are available free of charge on our website at www.momentus.space as soon as reasonably practicable after they are filed with, or furnished to, the SEC. Our website and the information contained on that site, or connected to that site, are not incorporated into and are not a part of this prospectus supplement. Copies of all documents incorporated by reference in this prospectus supplement, other than exhibits to those documents unless such exhibits are specially incorporated by reference in this prospectus supplement, will be provided at no cost to each person, including any beneficial owner, who receives a copy of this prospectus supplement on the written or oral request of that person made to:

This prospectus supplement and the accompanying prospectus contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), that are forward-looking and as such are not historical facts. These forward-looking statements include, without limitation, statements regarding Momentus’ or its management team’s expectations, hopes, beliefs, intentions or strategies regarding the future, projections, forecasts or other characterizations of future events or circumstances, including any underlying assumptions, and are not guarantees of future performance. The words “may,” “will,” “anticipate,” “believe,” “expect,” “continue,” “could,” “estimate,” “future,” “expect,” “intends,” “may,” “might,” “plan,” “possible,” “potential,” “aim,” “strive,” “predict,” “project,” “contemplate,” “objective,” “target,” “should,” “would” and similar expressions may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. Forward-looking statements in this prospectus may include, for example, statements about:

The following factors among others, could cause actual results and future events to differ materially from those set forth or contemplated in the forward-looking statements:

The forward-looking statements contained in this prospectus supplement are based on our current expectations and beliefs concerning future developments and their potential effects on our business. There can be no assurance that future developments affecting our business will be those that we have anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond our control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, those factors described in the section titled “Risk Factors” in this prospectus supplement, the accompanying prospectus, our most recent Annual Report on Form 10-K and our most recent Quarterly Report on Form 10-Q, as well as any subsequent filings with the SEC. Moreover, we operate in a very competitive and rapidly changing environment. New risks and uncertainties emerge from time to time and it is not possible for us to predict all such risk factors, nor can we assess the effect of all such risk factors on our business or the extent to which any factor or combination of factors may cause actual results to differ materially from those contained in any forward-looking statements. Should one or more of these risks or uncertainties materialize, or should any of the assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements.

The forward-looking statements made by us in this prospectus supplement and the accompanying prospectus speak only as of the date of this prospectus supplement and the accompanying prospectus. Except to the extent required under the federal securities laws and rules and regulations of the SEC, we disclaim any obligation to update any forward-looking statement to reflect events or circumstances after the date on which the statement is made or to reflect the occurrence of unanticipated events. In light of these risks and uncertainties, there is no assurance that the events or results suggested by the forward-looking statements will in fact occur, and you are cautioned not to place undue reliance on these forward-looking statements.

Investing in our securities involves risks. Before you make a decision to buy our securities, in addition to the risks and uncertainties discussed in this section and above under “Cautionary Note Regarding Forward-Looking Statements,” you should carefully consider the specific risks incorporated by reference in this prospectus supplement to our most recent Annual Report on Form 10-K and any subsequent Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, and all other information contained or incorporated by reference into this prospectus supplement, as updated by our subsequent filings under the Exchange Act, and the risk factors and other information contained in the accompanying prospectus and any applicable free writing prospectus before acquiring any such securities. If any of these risks actually occur, it may materially harm our business, financial condition, liquidity and results of operations. As a result, the market price of our securities could decline, and you could lose all or part of your investment. Additionally, the risks and uncertainties incorporated by reference in this prospectus supplement or the accompanying prospectus are not the only risks and uncertainties that we face. Additional risks and uncertainties not presently known to us or that we currently believe to be immaterial may become material and adversely affect our business.

We are currently, and may in the future be, subject to substantial litigation, regulatory actions, government investigations, proceedings and similar actions including matters related to commercial disputes, intellectual property, employment, securities laws, disclosures, whistleblower, environmental, tax, accounting, class action, and product liability, as well as trade, regulatory and other claims related to our business and our industry. Such matters can be time-consuming, divert management’s attention and resources, cause us to incur significant expenses or liability or require us to change our business practices. Because of the potential risks, expenses and uncertainties of litigation, we may, from time to time, settle disputes, even where we believe that we have meritorious claims or defenses. Because litigation is inherently unpredictable, we cannot assure you that the results of any of these actions will not have a material adverse effect on our business, operating results or financial condition.

On July 15, 2021, July 22, 2021 and August 4, 2021 , three related putative securities class action lawsuits were filed in the United States District Court for the Central District of California against the Company, SRAC, Sponsor, certain officers and directors of SRAC and Mikhail Kokorich, the Company’s co-founder and former CEO, alleging that the defendants omitted certain material information in their public statements and disclosures regarding the Business Combination in violation of the securities laws, and seeking damages on behalf of a putative class of stockholders who purchased SRAC stock between October 7, 2020 and July 13, 2021. On October 20, 2021, the securities class actions were consolidated in the first filed matter under the caption In re Stable Road Acquisition Corp. Securities Litigation (Case No. 2:21-cv-05744-JFW-SHK) and on November 12, 2021 the court-appointed lead plaintiff filed a consolidated amended complaint against the same defendants as well as certain additional officers and directors of SRAC and current and former officers of the Company. The amended complaint alleges that the defendants made certain material misrepresentations, and omitted certain material information, in their public statements and disclosures regarding the Business Combination, in violation of the securities laws, and seeks damages on behalf of a putative class of stockholders who purchased SRAC stock between October 7, 2020 and July 13, 2021. On February 14, 2022, the defendants filed motions to dismiss the amended complaint. On July 13, 2022 the motions to dismiss were granted in part and denied in part. A mediation has been scheduled for October 17, 2022 among the parties to the suit. A jury trial date has been set for November 14, 2023.

On June 16, 2022, a complaint was filed against the Company in the Delaware Court of Chancery (Case. No. 2022-0519) by a stockholder of the Company demanding to inspect the books and records of the Company pursuant to Section 220 of the Delaware General Corporation Law. The stockholder is seeking production of books and records relating to the management of the Company and its disclosures to potential investors in connection with the Business Combination. The matter is currently stayed pending the Company’s production of certain documents to satisfy the stockholder’s requests for inspection. The Company from time to time responds to books and records requests properly submitted pursuant to applicable Delaware law.

On June 20, 2022, a shareholder derivative action was filed by a stockholder on behalf of the Company, in the U.S. District Court for the Central District of California (Case No. 2:22-cv-04212), against the Company (as a

nominal defendant), SRAC, and current and former directors of the Company and SRAC. This derivative action alleges the same core allegations as stated in the securities class action litigation. Defendants dispute the allegations and intend to file a motion to dismiss the derivative action.

On July 20, 2022, an action was filed against the Company in New Castle County Superior Court, Delaware, in the Complex Commercial Litigation Division (Case No. N22C-07-133 EMD CCLD), alleging fraudulent inducement and breach of contract arising from two investment contracts pursuant to which plaintiff alleges it invested $4 million in the Company. The plaintiff is seeking damages in excess of $7.6 million, in addition to interests and its attorney’s fees and costs. The Company disputes the allegations and intends to vigorously defend the litigation.

On June 8, 2021, former co-founders and shareholders of the Company, Mikhail Kokorich and Lev Khasis signed a National Security Agreement alongside a Stock Repurchase Agreement, whereby they agreed to divest their interests in the Company in exchange for a cash payment and other considerations. The Company has maintained that this release is effective as to various advancement and indemnification claims either individual may have against the Company. On August 16, 2022, Mr. Kokorich filed a verified complaint against Momentus in the Delaware Court of Chancery (Case. No. 2022-0722) seeking indemnification and advancement from Momentus. Momentus disputes the allegations and intends to file a motion to dismiss the action.

These securities class actions, shareholder derivative actions and other current or future litigation matters may be time-consuming, divert management’s attention and resources, cause the Company to incur significant defense and settlement costs or liability, even if we believe the claims asserted against us are without merit. We intend to vigorously defend against all such claims. Because of the potential risks, expenses and uncertainties of litigation, as well as claims for indemnity from various of the parties concerned, we may from time to time, settle disputes, even where we believe that we have meritorious claims or defenses. While a certain amount of insurance coverage is available for expenses or losses associated with current or future lawsuits, this coverage may not be sufficient. Determining reserves for any litigation is a complex, fact-intensive process that is subject to judgment calls. It is possible that a resolution of one or more such proceedings could require us to make substantial payments to satisfy judgments, fines or penalties or to settle claims or proceedings, any of which could harm our business. Based on information currently available, we are unable to estimate reasonably a possible loss or range of possible losses, if any, with regard to the current securities class actions, shareholder derivative actions and other lawsuits; therefore, no litigation reserve has been recorded in our consolidated balance sheet. Although we plan to defend against the securities class actions, shareholder derivative actions and other lawsuits vigorously, we cannot assure that the results of these actions, either individually or in the aggregate, will not have a material adverse effect on our business, operating results or financial condition.

We intend to use the net proceeds from this offering for general corporate purposes, which may include working capital, capital expenditures, repayment and refinancing of debt, research and development expenditures, acquisitions of additional companies or technologies and investments. However, our management will have broad discretion in the application of the net proceeds from this offering and could spend the proceeds in ways that do not improve our results of operations or enhance the value of our Class A Stock. The failure by management to apply these funds effectively could result in financial losses that could have a material adverse effect on our business and cause the price of our Class A Stock to decline.

The price per share of our Class A Stock being offered may be higher than the net tangible book value per share of our Class A Stock outstanding prior to this offering. The shares sold in this offering, if any, will be sold from time to time at various prices. After giving effect to the sale of our Class A Stock in the maximum aggregate offering amount of $50.0 million at an assumed offering price of $1.40 per share, the last reported sale price of our Class A Stock on the Nasdaq Global Select Market on September 27, 2022, and after deducting estimated offering commissions payable by us, our net tangible book value as of June 30, 2022, would have been approximately $130.0 million, or $1.10 per share of Class A Stock. This represents an immediate increase in the net tangible book

value of $0.12 per share to our existing stockholders and an immediate and substantial dilution in net tangible book value of $0.30 per share to new investors who purchase our Class A Stock in the offering. See the section of this prospectus supplement titled “Dilution” for a more detailed discussion of the dilution you may incur in connection with this offering.

Sales of a substantial number of shares of our Class A Stock in the public markets could depress the market price of our Class A Stock and impair our ability to raise capital through the sale of additional equity securities. We cannot predict the effect that future sales of our Class A Stock would have on the market price of our Class A Stock.

Any issuance of equity we may undertake in the future to raise additional capital could cause the price of our Class A Stock to decline, or require us to issue shares at a price that is lower than that paid by holders of our Class A Stock in the past, which would result in those newly issued shares being dilutive. In addition, the price per share at which we sell additional shares of our Class A Stock, or securities convertible or exchangeable into Class A Stock, in future transactions may be higher or lower than the price per share paid by investors in this offering. If we obtain funds through a credit facility or through the issuance of debt or preferred securities, these securities will likely have rights senior to the rights of a common stockholder, which could impair the value of our Class A Stock.

Investors who purchase shares in this offering at different times will likely pay different prices, and so may experience different levels of dilution and different outcomes in their investment results. We will have discretion, subject to market demand, to vary the timing, prices and numbers of shares sold in this offering. In addition, there is no minimum or maximum sales price for shares to be sold in this offering. Investors may experience a decline in the value of the shares they purchase in this offering as a result of sales made at prices lower than the prices they paid.

Our common stock and publicly traded warrants currently trade on The Nasdaq Global Select Market. The Nasdaq Stock Market LLC has requirements for our equity securities to remain listed on Nasdaq, including a rule requiring our common stock to maintain a minimum closing bid price of $1.00 per share. The closing price of our common stock could fall below $1.00 per share in the future. If the closing bid price of our common stock falls below $1.00 per share for a period of 30 consecutive trading days, we would expect to receive a notification from Nasdaq that our common stock would be subject to delisting if we do not regain compliance with the minimum bid price requirement within the time period specified by Nasdaq. If we were to receive such a notification, we expect that we would be afforded a grace period of 180 calendar days to regain compliance with the minimum bid price requirement, and that, to regain compliance, our common stock would need to maintain a minimum closing bid price of at least $1.00 per share for at least 10 consecutive trading days. If we fail to meet Nasdaq’s stock price requirements, or if we do not meet Nasdaq’s other listing requirements, we would fail to be in compliance with Nasdaq’s listing standards and our common stock and publicly traded warrants could be delisted from Nasdaq. There can be no assurance that we will continue to meet the minimum bid price requirement or any other Nasdaq listing requirement in the future. If our common stock and publicly traded warrants were to be delisted, the liquidity of our common stock and publicly traded warrants would be adversely affected, their market prices could decrease. We may also face other adverse consequences in such event, such as negative publicity, a decreased ability to obtain additional financing, diminished investor and/or employee confidence, and the loss of business development opportunities, some or all of which may contribute to a further decline in our stock price.

We intend to use the net proceeds, if any, from the sale of Class A Stock offered hereby for general corporate purposes, which may include the development of the Vigoride orbital transfer vehicle, research and development efforts relating to Vigoride technology insertion, working capital, capital expenditures, repayment and refinancing of debt, research and development expenditures, acquisitions of additional companies or technologies and investments. From time to time, we engage in preliminary discussions and negotiations with various businesses in order to explore the possibility of an acquisition or investment. However, as of the date of this prospectus supplement, we have not entered into any agreements or arrangements which would make any acquisition or investment probable.

The net proceeds from the offering, if any, are not determinable in light of the nature of the offering. The net proceeds of any given sale of Class A Stock through the Sales Agent in an “at-the-market offering” will represent the gross proceeds after deducting the compensation payable to the Sales Agent under the ATM Sales Agreement and expenses of the offering. The Sales Agent will receive a fee not exceeding 3.0% of the gross proceeds realized from the sale of our Class A Stock, if any, for services rendered in connection with the offering.

We have not determined the amounts we plan to spend on the areas listed above or the timing of these expenditures. As a result, our management will have broad discretion to allocate the net proceeds of this offering.

We have never paid any cash dividends on our Class A Stock. Our board of directors currently intends to retain any future earnings to support operations and to finance the growth and development of our business and does not intend to pay cash dividends on our Class A Stock for the foreseeable future. Any future determination related to our dividend policy will be made at the discretion of our board of directors.

If you invest in this offering, your ownership interest will be diluted to the extent of the difference between the public offering price per share and the as adjusted net tangible book value per share after giving effect to this offering. We calculate net tangible book value per share by dividing the net tangible book value, which is tangible assets less total liabilities, by the number of outstanding shares of our Class A Stock. Dilution represents the difference between the portion of the amount per share paid by purchasers of shares in this offering and the as-adjusted net tangible book value per share of our Class A Stock immediately after giving effect to this offering. Our net tangible book value as of June 30, 2022 was approximately $81.5 million, or $0.98 per share of Class A Stock.

After giving effect to the sale of our Class A Stock in total aggregate amount of $50.0 million at an assumed offering price of $1.40, the last reported sale price of our Class A Stock on September 27, 2022 on the Nasdaq Select Global Market, and after deducting commissions and estimated aggregate offering expenses payable by us, our net tangible book value as of June 30, 2022 would have been approximately $130.0 million, or $1.10 per share of Class A Stock. This represents an immediate increase in the net tangible book value of $0.12 per share to our existing stockholders and an immediate dilution in net tangible book value of $0.30 per share to new investors.

The following table illustrates this per share dilution:

The table above assumes for illustrative purposes that a total aggregate amount of $50.0 million of our Class A Stock is sold pursuant to this prospectus supplement and the accompanying prospectus at a price of $1.40 per share, the last reported sale price of our Class A Stock on the Nasdaq Global Select Market on September 27, 2022. The shares of Class A Stock sold in this offering, if any, will be sold from time to time at various prices. An increase of $1.00 per share in the price at which the shares are sold from the assumed public offering price of $1.40 per share shown in the table above, assuming all of our shares of Class A Stock in the aggregate amount of $50.0 million are sold at that price, would increase the dilution in net tangible book value per share to new investors in this offering by $0.85 per share, after deducting commissions and estimated offering expenses payable by us. A decrease of $1.00 per share in the price at which the shares are sold from the assumed public offering price of $1.40 per share shown in the table above, assuming all of our shares in the aggregate amount of $50.0 million are sold at that price, would decrease the dilution in net tangible book value per share to new investors in this offering by $0.53 per share, after deducting commissions and estimated offering expenses payable by us. This information is supplied for illustrative purposes only.

The foregoing table and discussion are based on 83,264,832 shares of Class A Stock outstanding as of June 30, 2022 and excludes, as of June 30, 2022, 7,432,534 shares subject to unvested restricted stock units, 1,363,167 shares of our Class A Stock reserved for future grants under our 2021 Equity Incentive Plan (the “2021 Plan”), and 1,723,747 shares subject to restricted stock units and 2,276,253 shares of our Class A Stock reserved for future grants under our 2022 Inducement Equity Plan (the “2022 Plan”), as well as any automatic increases in the number of shares of Class A Stock reserved for future issuance under the 2021 Plan and the 2022 Plan. To the extent that unvested restricted stock units vest, there may be further dilution to new investors. In addition, we may choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders.

We have entered into an At-the-Market Equity Offering Sales Agreement (the “ATM Sales Agreement”), with Stifel, Nicolaus & Company, Incorporated (the “Sales Agent”), dated September 28, 2022, under which we may issue and sell shares of our Class A Stock having an aggregate gross sales price of up to $50,000,000 from time to time through the Sales Agent, acting as sales agent, subject to certain limitations. Sales of our Class A Stock, if any, under this prospectus supplement may be made in sales deemed to be “at the market offerings” as defined in Rule 415 promulgated under the Securities Act. We may instruct the Sales Agent not to sell our Class A Stock if the sales cannot be effected at or above the price designated by us from time to time. We or the Sales Agent may suspend the offering of our Class A Stock upon notice and subject to other conditions.

Each time we wish to issue and sell Class A Stock under the ATM Sales Agreement, we will notify the Sales Agent of the number of shares to be issued, the dates on which such sales are anticipated to be made, any minimum price below which sales may not be made and other sales parameters as we deem appropriate. Once we have so instructed the Sales Agent, unless the Sales Agent declines to accept the terms of the notice, the Sales Agent has agreed to use its commercially reasonable efforts consistent with its normal trading and sales practices to sell such shares up to the amount specified on such terms. The obligations of the Sales Agent under the ATM Sales Agreement to sell our Class A Stock are subject to a number of conditions that we must meet.

We will pay the Sales Agent commissions for its services in acting as an agent in the sale of our Class A Stock. The Sales Agent will be entitled to compensation at a commission rate of up to 3.0% of the gross sales price per share sold. Because there is no minimum offering amount required as a condition to closing this offering, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. In addition, we have agreed to reimburse the Sales Agent for fees and disbursements related to its legal counsel in an amount not to exceed $90,000, plus an additional amount not to exceed $5,000 per fiscal quarter on an ongoing basis during the term of the ATM Sales Agreement and for certain other expenses. We estimate that the total expenses for the offering, excluding compensation payable to the Sales Agent under the terms of the ATM Sales Agreement, will be approximately $250,000.

Settlement for sales of our Class A Stock will occur on the second (2nd) business day that is also a trading day following the date on which any sales are made, or on such earlier day as is then industry practice for regular-way trading or on some other date that is agreed upon by us and the Sales Agent in connection with a particular transaction, in return for payment of the net proceeds to us. There is no arrangement for funds to be received in an escrow, trust or similar arrangement.

The Sales Agent will provide written confirmation to us following the close of trading on The Nasdaq Global Select Market on each day in which Class A Stock is sold through it as sales agent under the ATM Sales Agreement. Each confirmation will include the number of shares of Class A Stock sold through it as sales agent on that day, the compensation payable by us to the Sales Agent and net proceeds to us.

In connection with the sale of the Class A Stock on our behalf, the Sales Agent will, with respect to sales effected in an “at the market offering,” be deemed to be an “underwriter” within the meaning of the Securities Act, and the compensation of the Sales Agent will be deemed to be underwriting commissions or discounts. We have agreed to provide indemnification and contribution to the Sales Agent against certain civil liabilities, including liabilities under the Securities Act.

The offering pursuant to the ATM Sales Agreement will terminate upon the earlier of (i) the issuance and sale of all shares of our Class A Stock subject to the ATM Sales Agreement or (ii) the termination of the ATM Sales Agreement as permitted therein.

This summary of the material provisions of the ATM Sales Agreement does not purport to be a complete statement of its terms and conditions.

The Sales Agent and its affiliates may in the future provide various investment banking and other financial services for us and our affiliates, for which services they may in the future receive customary fees. To the extent required by Regulation M, the Sales Agent will not engage in any market making or stabilizing activities involving our Class A Stock while the offering is ongoing under this prospectus supplement and the accompanying prospectus.

Bradley Arant Boult Cummings LLP has passed upon the validity of the Class A Stock offered hereby. Goodwin Procter LLP is representing the Sales Agent in connection with this offering.

The financial statements of Momentus Inc. as of and for the years ended December 31, 2021 and 2020, and for each of the three years in the period ended December 31, 2021, incorporated by reference in this prospectus have been audited by Armanino LLP, an independent registered public accounting firm, as stated in their report incorporated by reference herein. Such financial statements have been so incorporated by reference in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

We are required to file annual, quarterly and current reports, proxy statements and other information with the SEC as required by the Exchange Act. You can read our SEC filings, including this prospectus, over the Internet at the SEC’s website at www.sec.gov. Those filings are also available to the public on, or accessible through, our website on at investors.momentus.space. The information we file with the SEC or contained on or accessible through our corporate website or any other website that we may maintain is not part of this prospectus supplement and the accompanying prospectus, or the registration statement of which this prospectus supplement and the accompanying prospectus is a part. You may inspect a copy of the registration statement through the SEC’s website, as provided herein.

This prospectus supplement and the accompanying prospectus are part of a registration statement on Form S-3 that we filed with the SEC and do not contain all of the information in the registration statement. The full registration statement may be obtained from the SEC or us, as provided above. Forms of documents establishing the terms of any offered securities are or may be filed as exhibits to the registration statement or documents incorporated by reference in the registration statement. Statements in this prospectus supplement and the accompanying prospectus about these documents are summaries and each statement is qualified in all respects by reference to the document to which it refers. You should refer to the actual documents for a more complete description of the relevant matters. You may inspect a copy of the registration statement through the SEC’s website, as provided above.

From time to time, Momentus Inc. (“Momentus,” the “Company,” “we,” “us,” or “our”) may offer and sell any combination of the securities described in this prospectus in one or more offerings. We may offer the securities separately or together, in amounts, at prices and on terms that will be determined at the time the securities are offered. The aggregate public offering price of all securities issued by us under this prospectus may not exceed $200,000,000.00.

This prospectus describes some of the general terms that may apply to these securities. Each time securities are sold, the specific terms and amounts of the securities being offered, and any other information relating to the specific offering will be set forth in a supplement to this prospectus. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. The prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, as well as any documents incorporated by reference, before you invest in any of the securities being offered. This prospectus may not be used to sell our securities unless accompanied by a prospectus supplement.

We may offer and sell our securities to or through one or more underwriters, dealers and agents, or directly to purchasers, on an immediate, continuous or delayed basis. The names of any underwriters, dealers or agents and the terms of the arrangements with such entities will be stated in the accompanying prospectus supplement. See the sections of this prospectus entitled “About this Prospectus” and “Plan of Distribution” for more information.

Our Class A common stock (“Class A Stock”) and our public warrants to purchase shares of our Class A Stock (“Public Warrants”) are listed on the Nasdaq Global Select Market under the symbols “MNTS” and “MNTSW,” respectively. On August 31, 2022, the last reported sales price of our Class A Stock and our Public Warrants were $1.77 per share and $0.24 per warrant.

Our principal executive offices are located at 3901 N. First Street, San Jose, CA 95134. Our telephone number is (650) 564-7820.

We are an “emerging growth company” as defined in Section 2(a) of the Securities Act of 1933, as amended, and, as such, have elected to comply with certain reduced disclosure and regulatory requirements.

Investing in our securities involves risks. You should carefully review the risks and uncertainties referenced in the section of this prospectus entitled “Risk Factors” as well as those contained in the applicable prospectus supplement and any related free writing prospectus, and in the other documents that are incorporated by reference into this prospectus or the applicable prospectus supplement before you consider buying our securities.

Neither the Securities and Exchange Commission (the “SEC”) nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Unless the context indicates otherwise, references in this prospectus to the “Company,” “Momentus,”, the “Registrant,” “we,” “us,” “our” and similar terms refer to Momentus Inc. (f/k/a Stable Road Acquisition Corp.) and its consolidated subsidiaries.

This registration statement incorporates by reference important business and financial information about the Company that is not included in or delivered with this document. The information incorporated by reference is considered to be part of this prospectus, and the SEC allows us to “incorporate by reference” the information we file with it, which means that we can disclose important information to you by referring you to those documents instead of having to repeat the information in this prospectus. Any statement contained in any document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in or omitted from this prospectus or any accompanying prospectus supplement, or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein, modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus. We incorporate by reference:

All documents filed by the Company pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act after the date of this prospectus and prior to the filing of a post-effective amendment which indicates that all securities offered hereby have been sold or which deregisters all securities then remaining unsold shall be deemed to be incorporated by reference into this prospectus and to be a part hereof from the date of filing of such documents; provided, however, that documents or information deemed to have been furnished, and exhibits furnished in connection with such items, and not filed in accordance with the rules of the SEC shall not be deemed incorporated by reference into this prospectus.

We have filed with the SEC this registration statement under the Securities Act of 1933, as amended (the “Securities Act”), covering the securities that may be offered and sold by this prospectus and any applicable prospectus supplement. This prospectus does not contain all of the information included in the registration statement, some of which is contained in exhibits to the registration statement. The registration statement, including the exhibits, can be read at the SEC website referred to below under “Where You Can Find More Information.” Any statement made in this prospectus or any prospectus supplement concerning the contents of any contract, agreement or other document is only a summary of the actual contract, agreement or other document. If we have filed any contract, document, agreement or other document as an exhibit to the registration statement or any other document incorporated herein by reference, you should read the exhibit for a more complete understanding of the document or matter involved. Each statement regarding a contract, agreement or other document is qualified in its entirety by reference to the actual document.

Our filings with the SEC, including Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and amendments to those reports, are available free of charge on our website at www.momentus.space as soon as reasonably practicable after they are filed with, or furnished to, the SEC. Our website and the information contained on that site, or connected to that site, are not incorporated into and are not a part of this prospectus. Copies of all documents incorporated by reference in this prospectus, other than exhibits to those documents unless such exhibits are specially incorporated by reference in this prospectus, will be provided at no cost to each person, including any beneficial owner, who receives a copy of this prospectus on the written or oral request of that person made to:

This prospectus is a part of a registration statement that we filed with the SEC, under the Securities Act using a “shelf” registration process. Under this shelf registration statement, we may sell securities from time to time in one or more offerings as described in this prospectus up to a total dollar amount of $200,000,000.00. This prospectus provides you with a general description of the securities we may offer. Each time we sell any type or series of securities under this prospectus, we will provide a prospectus supplement that will contain more specific information about the terms of that offering.

This prospectus does not contain all of the information included in the registration statement. For a more complete understanding of the offering of the securities, you should refer to the registration statement, including its exhibits. We may add, update or change in a prospectus supplement or free writing prospectus any of the information contained in this prospectus or in the documents we have incorporated by reference into this prospectus. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. This prospectus, together with the applicable prospectus supplement, any related free writing prospectus and the documents incorporated by reference into this prospectus and the applicable prospectus supplement, will include all material information relating to the applicable offering. You should carefully read both this prospectus and the applicable prospectus supplement and any related free writing prospectus, together with the additional information described under the section of this prospectus entitled, “Information Incorporated by Reference” in making your investment decision.

We have not authorized any dealer, agent or other person to give any information or to make any representation other than those contained or incorporated by reference in this prospectus, any accompanying prospectus supplement or any related free writing prospectus that we may authorize to be provided to you. You must not rely upon any information or representation not contained or incorporated by reference in this prospectus or an accompanying prospectus supplement, or any related free writing prospectus that we may authorize to be provided to you. This prospectus, the accompanying prospectus supplement and any related free writing prospectus, if any, do not constitute an offer to sell or the solicitation of an offer to buy any securities other than the registered securities to which they relate, nor do this prospectus, the accompanying prospectus supplement or any related free writing prospectus, if any, constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation in such jurisdiction. You should not assume that the information contained in this prospectus, any applicable prospectus supplement or any related free writing prospectus is accurate on any date subsequent to the date set forth on the front of the document or that any information we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference (as our business, financial condition, results of operations and prospects may have changed since that date), even though this prospectus, any applicable prospectus supplement or any related free writing prospectus is delivered or securities are sold on a later date.

We further note that the representations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is incorporated by reference in this prospectus were made solely for the benefit of the parties to such agreement, including, in some cases, for the purpose of allocating risk among the parties to such agreements, and should not be deemed to be a representation, warranty or covenant to you. Moreover, such representations, warranties or covenants were accurate only as of the date when made. Accordingly, such representations, warranties and covenants should not be relied on as accurately representing the current state of our affairs.

This prospectus may not be used to consummate sales of our securities, unless it is accompanied by a prospectus supplement. To the extent there are inconsistencies between any prospectus supplement, this prospectus and any documents incorporated by reference, the document with the most recent date will control.

As permitted by the rules and regulations of the SEC, the registration statement, of which this prospectus forms a part, includes additional information not contained in this prospectus. You may read the registration statement and the other reports we file with the SEC at the SEC’s website or at the SEC’s offices described below under the section of this prospectus entitled, “Where You Can Find More Information.”

This prospectus and any accompanying prospectus supplement contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), that are forward-looking and as such are not historical facts. These forward-looking statements include, without limitation, statements regarding Momentus’ or its management team’s expectations, hopes, beliefs, intentions or strategies regarding the future, projections, forecasts or other characterizations of future events or circumstances, including any underlying assumptions, and are not guarantees of future performance. The words “may,” “will,” “anticipate,” “believe,” “expect,” “continue,” “could,” “estimate,” “future,” “expect,” “intends,” “may,” “might,” “plan,” “possible,” “potential,” “aim,” “strive,” “predict,” “project,” “contemplate,” “objective,” “target,” “should,” “would” and similar expressions may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. Forward-looking statements in this prospectus may include, for example, statements about:

The following factors among others, could cause actual results and future events to differ materially from those set forth or contemplated in the forward-looking statements:

The forward-looking statements contained in this prospectus are based on our current expectations and beliefs concerning future developments and their potential effects on our business. There can be no assurance that future developments affecting our business will be those that we have anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond our control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, those factors described in the section titled “Risk Factors” in this prospectus, our most recent Annual Report on Form 10-K and our most recent Quarterly Report on Form 10-Q, as well as any subsequent filings with the SEC. Moreover, we operate in a very competitive and rapidly changing environment. New risks and uncertainties emerge from time to time and it is not possible for us to predict all such risk factors, nor can we assess the effect of all such risk factors on our business or the extent to which any factor or combination of factors may cause actual results to differ materially from those contained in any forward-looking statements. Should one or more of these risks or uncertainties materialize, or should any of the assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements.

The forward-looking statements made by us in this prospectus and any accompanying prospectus supplement speak only as of the date of this prospectus and any accompanying prospectus supplements. Except to the extent required under the federal securities laws and rules and regulations of the SEC, we disclaim any obligation to update any forward-looking statement to reflect events or circumstances after the date on which the statement is made or to reflect the occurrence of unanticipated events. In light of these risks and uncertainties, there is no assurance that the events or results suggested by the forward-looking statements will in fact occur, and you are cautioned not to place undue reliance on these forward-looking statements.

Investing in our securities involves risks. Before you make a decision to buy our securities, in addition to the risks and uncertainties discussed above under “Cautionary Note Regarding Forward-Looking Statements,” you should carefully consider the specific risks incorporated by reference in this prospectus to our most recent Annual Report on Form 10-K and any subsequent Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, and all other information contained or incorporated by reference into this prospectus, as updated by our subsequent filings under the Exchange Act, and the risk factors and other information contained in any applicable prospectus supplement and any applicable free writing prospectus before acquiring any such securities. If any of these risks actually occur, it may materially harm our business, financial condition, liquidity and results of operations. As a result, the market price of our securities could decline, and you could lose all or part of your investment. Additionally, the risks and uncertainties incorporated by reference in this prospectus or any prospectus supplement are not the only risks and uncertainties that we face. Additional risks and uncertainties not presently known to us or that we currently believe to be immaterial may become material and adversely affect our business.

Momentus is a U.S. commercial space company that plans to offer transportation and infrastructure services to help enable the commercialization of space. Satellite operators are our principal customers and target customers. Services that we plan to provide include “last mile” satellite transportation, payload-hosting, on-orbit satellite refueling, on-orbit inspection, on-orbit satellite maintenance, de-orbiting, debris removal, and other satellite-to-satellite service offerings.

Our transportation service offering will focus on delivering our customers’ satellites to precision orbits of their choosing. To accomplish this, we plan to create a hub-and-spoke transportation network in partnership with leading launch service providers, such as SpaceX. Under this model, our customers’ satellites would “ride share” from Earth to space on a midsized or large rocket. Our Orbital Transfer Vehicles (“OTVs”) would then provide “last mile” transportation services from the rocket’s drop-off orbit to a custom orbit of the satellite operator’s choosing. We believe our hub-and-spoke model has the potential to expand our customers’ deployment options relative to what they would be able to achieve with ride share launch alone, while reducing their costs relative to what they could achieve with a dedicated small launch vehicle. Over time, we plan to begin introducing additional services beyond “last mile” transportation.

Since our founding in 2017, we have been working to develop, test and enhance our vehicles and supporting technologies, particularly our water plasma propulsion technology.

Unless stated otherwise in a prospectus supplement, the net proceeds from the sale of securities described in this prospectus, if any, will be used for general corporate purposes, including, without limitation, any potential business acquisitions.

The following description summarizes the most important terms of our capital stock. This description is summarized from, and qualified in its entirety by reference to, our certificate of incorporation and bylaws, which have been publicly filed with the SEC. See “Information Incorporated by Reference.” The summary below is also qualified by reference to the provisions of the General Corporation Law of the State of Delaware (the “DGCL”).

Pursuant to the terms of the Second Amended and Restated Certificate of Incorporation, our authorized capital stock consists of:

As of August 5, 2022, there were 83,276,728 shares of Class A common stock issued and outstanding and no shares of Preferred Stock outstanding.

Holders of Class A common stock are entitled to one vote per share on all matters submitted to a vote of stockholders. The holders of Class A common stock will generally vote together as a single class on all matters submitted to a vote of stockholders, unless otherwise required by Delaware law or the Second Amended and Restated Certificate of Incorporation.

The Second Amended and Restated Certificate of Incorporation and the Amended and Restated Bylaws (collectively, our “Organizational Documents”) established a classified board of directors (the “board”) that is divided into three classes with staggered three-year terms. Only the directors in one class will be subject to election by a plurality of the votes cast at each annual meeting of stockholders, with the directors in the other classes continuing for the remainder of their respective three-year terms. The Second Amended and Restated Certificate of Incorporation does not provide for cumulative voting for the election of directors.

Subject to preferences that may apply to any shares of Preferred Stock outstanding at the time, the holders of Class A common stock are entitled to receive dividends out of funds legally available if the board, in its discretion, determines to issue dividends and then only at the times and in the amounts that the board may determine.

We have not paid any cash dividends on our common stock to date and do not intend to pay cash dividends in the foreseeable future. The payment of cash dividends in the future will be dependent upon our revenues and earnings, if any, capital requirements, the terms of any outstanding indebtedness and general financial condition. The payment of any cash dividends will be within the discretion of the board at such time. In addition, the board is not currently contemplating and does not anticipate declaring any stock dividends in the foreseeable future.

The holders of our Class A common stock are not entitled to preemptive rights and are not subject to conversion (except as noted above), redemption or sinking fund provisions.

If we become subject to a liquidation, dissolution or winding-up, the assets legally available for distribution to our stockholders would be distributable ratably among the holders of Class A common stock and any participating Preferred Stock outstanding at that time, subject to prior satisfaction of all outstanding debt and liabilities and the preferential rights of and the payment of liquidation preferences, if any, on any outstanding shares of Preferred Stock.

All of the outstanding shares of Class A common stock are fully paid and non-assessable.

Our board is authorized, subject to limitations prescribed by Delaware law, to issue Preferred Stock in one or more series, to establish from time to time the number of shares to be included in each series, and to fix the designation, vesting, powers, preferences, and rights of the shares of each series and any of its qualifications, limitations, or restrictions, in each case without further vote or action by the stockholders. Our board can also increase or decrease the number of shares of any series of Preferred Stock, but not below the number of shares of that series then outstanding, without any further vote or action by the stockholders.

Our board may authorize the issuance of Preferred Stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of Class A common stock. The issuance of Preferred Stock, while providing flexibility in connection with possible acquisitions and other corporate purposes, could, among other things, have the effect of delaying, deferring, or preventing a change in control of the Company and may adversely affect the market price of Class A common stock and the voting and other rights of the holders of Class A common stock. There are no current plans to issue any shares of Preferred Stock.

Some provisions of Delaware law, the Second Amended and Restated Certificate of Incorporation, and the Amended and Restated Bylaws contain provisions that could make the following transactions more difficult: an acquisition of us by means of a tender offer, an acquisition of us by means of a proxy contest or otherwise, or the removal of our incumbent officers and directors. It is possible that these provisions could make it more difficult to accomplish or could deter transactions that stockholders may otherwise consider to be in their best interest or in our best interests, including transactions that provide for payment of a premium over the market price for our shares.

These provisions, summarized below, are intended to discourage coercive takeover practices and inadequate takeover bids. These provisions are also designed to encourage persons seeking to acquire control of us to first negotiate with our board. We believe that the benefits of the increased protection of our potential ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure us outweighs the disadvantages of discouraging these proposals because negotiation of these proposals could result in an improvement of their terms.

We are subject to the provisions of Section 203 of the DGCL regulating corporate takeovers. In general, Section 203 prohibits a publicly-held Delaware corporation from engaging in a business combination with an interested stockholder for a period of three years following the date on which the person became an interested stockholder unless:

Generally, a “business combination” includes a merger, asset or stock sale, or other transaction or series of transactions together resulting in a financial benefit to the interested stockholder. An interested stockholder is a person who, together with affiliates and associates, owns or, within three years prior to the determination of interested stockholder status, did own 15% or more of a corporation’s outstanding voting stock. We expect the existence of this provision to have an anti-takeover effect with respect to transactions the board does not approve in advance. We also anticipate that Section 203 may also discourage attempts that might result in a premium over the market price for the shares of common stock held by stockholders.

Provisions of our Organizational Documents could make it more difficult to acquire us by means of a tender offer, a proxy contest or otherwise, or to remove incumbent officers and directors.

Our Second Amended and Restated Certificate of Incorporation and our Amended and Restated Bylaws provide for certain provisions that may have an anti-takeover effect:

Our Amended and Restated Bylaws provide that we will indemnify our directors and officers, and may indemnify our employees and other agents, to the fullest extent permitted by Delaware law.

Delaware law prohibits the Second Amended and Restated Certificate of Incorporation from limiting the liability of our directors for the following:

If Delaware law is amended to authorize corporate action further eliminating or limiting the personal liability of a director, then the liability of our directors will be eliminated or limited to the fullest extent permitted by Delaware law, as so amended. The Second Amended and Restated Certificate of Incorporation does not eliminate a director’s duty of care and, in appropriate circumstances, equitable remedies, such as injunctive or other forms of non-monetary relief, remain available under Delaware law. This provision also does not affect a director’s responsibilities under any other laws, such as the federal securities laws or other state or federal laws. Under our Amended and Restated Bylaws, we can purchase insurance on behalf of any person whom we are required or permitted to indemnify.

In addition to the indemnification required in our Organizational Documents, we have entered into an indemnification agreement with each member of our board and each of our officers. These agreements provide for the indemnification of our directors and officers for certain expenses and liabilities incurred in connection with any action, suit, proceeding or alternative dispute resolution mechanism, or hearing, inquiry or investigation that may lead

to the foregoing, to which they are a party or other participant, or are threatened to be made a party or other participant, by reason of the fact that they are or were a director, officer, employee, agent or fiduciary of us, by reason of any action or inaction by them while serving as an officer, director, agent or fiduciary, or by reason of the fact that they were serving at our request as a director, officer, employee, agent or fiduciary of another entity. In the case of an action or proceeding by or in the right of the Company, no indemnification will be provided for any claim where a court determines that the indemnified party is prohibited from receiving indemnification. We believe that these certificate of incorporation and bylaw provisions and indemnification agreements are necessary to attract and retain qualified persons as directors and officers.

The limitation of liability and indemnification provisions in our Organizational Documents may discourage stockholders from bringing a lawsuit against directors for breach of their fiduciary duties. They may also reduce the likelihood of derivative litigation against directors and officers, even though an action, if successful, might benefit us and our stockholders. Moreover, a stockholder’s investment may be harmed to the extent we pay the costs of settlement and damage awards against directors and officers pursuant to these indemnification provisions.

Our Class A common stock and Public Warrants are listed on the Nasdaq Global Select Market under the symbols “MNTS” and “MNTSW,” respectively.

The transfer agent and registrar for our Common Stock is Continental Stock Transfer & Trust Company.

This summary, together with the additional information we include in any applicable prospectus supplements, summarizes the material terms and provisions of the debt securities that we may offer under this prospectus. While the terms we have summarized below will generally apply to any future debt securities we may offer, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. The terms of any debt securities we offer under a prospectus supplement may differ from the terms we describe below.

The debt securities may be either secured or unsecured and will either be senior debt securities or subordinated debt securities. We will issue the senior notes under the senior indenture which we will enter into with one or more trustees whom we will identify in the applicable prospectus supplement. We will issue the subordinated notes under the subordinated indenture which we will enter into with one or more trustees whom we will identify in the applicable prospectus supplement. We have filed forms of the indentures as exhibits to the registration statement of which this prospectus forms a part. We use the term “indentures” to refer to both the senior indenture and the subordinated indenture.

The indentures will be qualified under the Trust Indenture Act of 1939, as amended (the “Trust Indenture Act”). We use the term “debenture trustee” to refer to either the senior trustee or the subordinated trustee, as applicable.

The following summaries of the material provisions of the senior notes, the subordinated notes and the indentures are subject to, and qualified in their entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplements related to the debt securities that we sell under this prospectus, as well as the complete indenture that contain the terms of the debt securities. Except as we may otherwise indicate, the terms of the senior indenture and the subordinated indenture are identical.

We will describe in the applicable prospectus supplement the terms relating to a series of debt securities, including, to the extent applicable:

We will set forth in the applicable prospectus supplements the terms, if any, on which a series of debt securities may be convertible into or exchangeable for common stock or other securities of ours or a third party, including the conversion or exchange rate, as applicable, or how it will be calculated, and the applicable conversion or exchange period. We will include provisions as to whether conversion or exchange is mandatory, at the option of the holder

or at our option. We may include provisions pursuant to which the number of our securities or the securities of a third party that the holders of the series of debt securities receive upon conversion or exchange would, under the circumstances described in those provisions, be subject to adjustment, or pursuant to which those holders would, under those circumstances, receive other property upon conversion or exchange, for example in the event of our merger or consolidation with another entity.

The indentures in the form initially filed as exhibits to the registration statement of which this prospectus forms a part may contain covenants that restrict our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of all or substantially all of our assets. However, any successor of ours or acquirer of such assets must assume all of our obligations under the indentures and the debt securities.

If the debt securities are convertible into our other securities, the person with whom we consolidate or merge or to whom we sell all of our property must make provisions for the conversion of the debt securities into securities which the holders of the debt securities would have received if they had converted the debt securities before the consolidation, merger or sale.

Unless otherwise specified in the applicable prospectus supplement, the following are events of default under the indentures with respect to any series of debt securities that we may issue:

If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the debenture trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series may, by notice to us in writing (and to the debenture trustee if notice is given by such holders), declare the unpaid principal, premium, if any, and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the principal amount of and accrued interest, if any, of each series of debt securities then outstanding shall be due and payable without any notice or other action on the part of the debenture trustee or any holder.

The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture.

Subject to the terms of the indentures, if an event of default under an indenture shall occur and be continuing, the debenture trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the debenture trustee reasonable indemnity. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the debenture trustee, or exercising any trust or power conferred on the debenture trustee, with respect to the debt securities of that series, provided that:

A holder of the debt securities of any series will only have the right to institute a proceeding under the indentures or to appoint a receiver or trustee, or to seek other remedies, if:

These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on the debt securities.

If debt securities are issued, the indentures require that we periodically file statements with the debenture trustee regarding our compliance with specified covenants in the indentures.

We and the debenture trustee may modify an indenture without the consent of any holders with respect to specific matters, including, without limitation:

In addition, under the indentures, the rights of holders of debt securities of any series may be changed by us and the debenture trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, we and the debenture trustee may only make the following changes with the consent of each holder of any outstanding debt securities affected:

The indentures provide that we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for certain obligations, including obligations to:

In order to exercise our rights to be discharged, we must deposit with the debenture trustee money or government obligations, or a combination of both, sufficient to pay all of the principal, premium, if any, and interest on the debt securities of the series on the dates payments are due.

The debenture trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the debenture trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs. Subject to this provision, the debenture trustee is under no obligation to exercise any of the powers given it by the indentures at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay principal of, and any premium and interest on, the debt securities of a particular series at the office of the paying agents designated by us, except that, unless we otherwise indicate in the applicable prospectus supplement, we may make certain payments by check which we will mail to the holder or by wire transfer to certain holders. We will name in the applicable prospectus supplement any paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

All money we pay to a paying agent or the debenture trustee for the payment of the principal of or any premium or interest on any debt securities which remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.

The indentures and the debt securities will be governed by and construed in accordance with the laws of the state of New York, except to the extent that the Trust Indenture Act is applicable.

The subordinated debt securities will be subordinate and junior in priority of payment to certain of our other indebtedness to the extent described in a prospectus supplement. The indentures in the form initially filed as exhibits to the registration statement of which this prospectus forms a part do not limit the amount of indebtedness which we may incur, including senior indebtedness or subordinated indebtedness, and do not limit us from issuing any other debt, including secured debt or unsecured debt. Additional or different subordination provisions may be described in a prospectus supplement relating to a particular series of debt securities.

This summary, together with the additional information we include in any applicable prospectus supplements, summarizes the material terms and provisions of the warrants that we may offer under this prospectus, which consist of warrants to purchase our Class A Stock, Preferred Stock and/or debt securities in one or more series. Warrants may be offered independently or together with our Class A Stock, Preferred Stock, debt securities and/or rights offered by any prospectus supplement and may be attached to or separate from those securities. While the terms we have summarized below will generally apply to any future warrants we may offer under this prospectus, we will describe the particular terms of any warrants that we may offer in more detail in the applicable prospectus supplement. The terms of any warrants we offer under a prospectus supplement may differ from the terms we describe below.

We will issue the warrants directly or under a warrant agreement which we will enter into with a warrant agent to be selected by us and identified in any applicable prospectus supplement. Each series of warrants will be issued under a separate warrant agreement to be entered into between us and a bank or trust company, as warrant agent, all as set forth in the prospectus supplement relating to the particular issue of offered warrants. We use the term “warrant agreement” to refer to any of these warrant agreements. We use the term “warrant agent” to refer to the warrant agent under any of these warrant agreements. The warrant agent will act solely as an agent of ours in connection with the warrants and will not act as an agent for the holders or beneficial owners of the warrants.

The following summary of material provisions of the warrants and the warrant agreements are subject to, and qualified in their entirety by reference to, all of the provisions of the warrant agreement applicable to a particular series of warrants. We urge you to read the applicable prospectus supplements related to the warrants that we sell pursuant to this prospectus, as well as the complete warrant agreements that contain the terms of the warrants.

We will describe in the applicable prospectus supplements the terms relating to a series of warrants.

If warrants for the purchase of our Class A Stock or Preferred Stock are offered, the prospectus supplements will describe the following terms, to the extent applicable:

Warrants for the purchase of Class A Stock or Preferred Stock will be in registered form only.

If warrants for the purchase of debt securities are offered, the prospectus supplement will describe the following terms, to the extent applicable:

Warrants for the purchase of debt securities will be in registered form only.

A holder of warrant certificates may exchange them for new certificates of different denominations, present them for registration of transfer and exercise them at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement. Until any warrants to purchase Class A Stock or Preferred Stock are exercised, holders of the warrants will not have any rights of holders of the underlying Class A Stock or Preferred Stock, including any rights to receive dividends or to exercise any voting rights, except to the extent set forth under “Warrant Adjustments” below. Until any warrants to purchase debt securities are exercised, the holder of the warrants will not have any of the rights of holders of the debt securities that can be purchased upon exercise, including any rights to receive payments of principal, premium or interest on the underlying debt securities or to enforce covenants in the applicable indenture.

Each holder of a warrant is entitled to purchase the number of shares of Class A Stock or Preferred Stock or principal amount of debt securities, as the case may be, at the exercise price described in the applicable prospectus supplements. After the close of business on the day when the right to exercise terminates (or a later date if we extend the time for exercise), unexercised warrants will become void.

A holder of warrants may exercise them by following the general procedure outlined below:

If the holder complies with the procedures described above, the warrants will be considered to have been exercised when we receive or the warrant agent receives, as applicable, payment of the exercise price, subject to the

transfer books for the securities issuable upon exercise of the warrant not being closed on such date. After the holder has completed those procedures and subject to the foregoing, we will, as soon as practicable, issue and deliver to such holder the Class A Stock, Preferred Stock or debt securities that such holder purchased upon exercise. If the holder exercises fewer than all of the warrants represented by a warrant certificate, a new warrant certificate will be issued to such holder for the unexercised amount of warrants. Holders of warrants will be required to pay any tax or governmental charge that may be imposed in connection with transferring the underlying securities in connection with the exercise of the warrants.

We may amend or supplement a warrant agreement without the consent of the holders of the applicable warrants to cure ambiguities in the warrant agreement, to cure, correct or supplement a defective provision in the warrant agreement, or to provide for other matters under the warrant agreement that we and the warrant agent deem necessary or desirable, so long as, in each case, such amendments or supplements do not materially adversely affect the interests of the holders of the warrants.

Unless the applicable prospectus supplements state otherwise, the exercise price of, and the number of securities covered by, a warrant to receive either Class A Stock or Preferred Stock will be adjusted proportionately if we subdivide or combine our Class A Stock or Preferred Stock, as applicable.

In addition, unless a prospectus supplement states otherwise, if we, without payment therefor:

Except as stated above, the exercise price and number of securities covered by a warrant to receive Class A Stock or Preferred Stock, and the amounts of other securities or property to be received, if any, upon exercise of those warrants, will not be adjusted or provided for if we issue those securities or any securities convertible into or exchangeable for those securities, or securities carrying the right to purchase those securities or securities convertible into or exchangeable for those securities.

Holders of warrants to receive Class A Stock and Preferred Stock may have additional rights under the following circumstances:

If one of the above transactions occurs and holders of our Class A Stock or Preferred Stock are entitled to receive stock, securities or other property with respect to or in exchange for their securities, the holders of the warrants to receive Class A Stock and Preferred Stock then outstanding, as applicable, will be entitled to receive upon exercise of their warrants the kind and amount of shares of stock and other securities or property that they would have received upon the applicable transaction if they had exercised their warrants immediately before the transaction.

This summary, together with the additional information we include in any applicable prospectus supplements, summarizes the material terms and provisions of the rights that we may offer under this prospectus, which consist of rights to purchase our Class A Stock, Preferred Stock and/or debt securities in one or more series. Rights may be offered independently or together with our Class A Stock, Preferred Stock, debt securities and/or warrants offered by any prospectus supplement and may be attached to or separate from those securities. While the terms we have summarized below will generally apply to any future rights we may offer pursuant to this prospectus, we will describe the particular terms of any rights that we may offer in more detail in the applicable prospectus supplements. The terms of any rights we offer under a prospectus supplement may differ from the terms we describe below.

The applicable prospectus supplements relating to any rights that we offer will include specific terms of any offering of rights for which this prospectus is being delivered, including the following, to the extent applicable:

The description in the applicable prospectus supplements of any rights that we may offer will not necessarily be complete and will be qualified in its entirety by reference to the applicable rights agreement and/or rights certificate, which will be filed with the SEC in connection therewith.

This summary, together with the additional information we include in any applicable prospectus supplements, summarizes the material terms and provisions of the units that we may offer under this prospectus, which may consist of one or more shares of Class A Stock, shares of Preferred Stock, debt securities, warrants, rights or any combination of such securities. While the terms we have summarized below will generally apply to any future units we may offer pursuant to this prospectus, we will describe the particular terms of any units that we may offer in more detail in the applicable prospectus supplements. The terms of any units we offer under a prospectus supplement may differ from the terms we describe below.

The applicable prospectus supplements relating to any units that we offer will include specific terms of any offering of units for which this prospectus is being delivered, including the following, to the extent applicable:

The description in the applicable prospectus supplements of any units that we may offer will not necessarily be complete and will be qualified in its entirety by reference to the applicable unit agreement, which will be filed with the SEC in connection therewith.

We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee, depositary or warrant agent maintain for this purpose as the “holders” of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as “indirect holders” of those securities. As we discuss below, indirect holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.

Only the person in whose name a security is registered is recognized as the holder of that security. Securities issued in global form will be registered in the name of the depositary or its participants. Consequently, for securities issued in global form, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

As a result, investors in a book-entry security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary’s book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not holders, of the securities.

We may terminate a global security or issue securities in non-global form. In these cases, investors may choose to hold their securities in their own names or in “street name.” Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.

Our obligations, as well as the obligations of any applicable trustee and of any third parties employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

For example, once we make a payment or give a notice to the holder, we have no further responsibility for the payment or notice even if that holder is required, under agreements with depositary participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of the indenture or for other purposes. In such an event, we would seek approval only from the holders, and not the indirect holders, of the securities. Whether and how the holders contact the indirect holders is up to the holders.

If you hold securities through a bank, broker or other financial institution, either in book-entry form or in street name, you should check with your own institution to find out:

A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.

Each security issued in book-entry form will be represented by a global security that we deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, the Depository Trust Company (“DTC”) will be the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations below under the section entitled “Special Situations When a Global Security Will Be Terminated” in this prospectus. As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for a particular security indicates that the security will be issued in global form only, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

The rights of an indirect holder relating to a global security will be governed by the account rules of the investor’s financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued only in the form of a global security, an investor should be aware of the following:

There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

In a few special situations described below, the global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks or brokers to find out how to have their interests in securities transferred to their own name, so that they will be direct holders. We have described the rights of holders and street name investors above.

Unless we provide otherwise in the applicable prospectus supplement, the global security will terminate when the following special situations occur:

The applicable prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the applicable prospectus supplement. When a global security terminates, the depositary, and not we or any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

We may offer and sell the securities being offered hereby in one or more of the following ways from time to time:

We will identify the specific plan of distribution, including any underwriters, dealers, agents or other purchasers, persons or entities, and any applicable compensation, in a prospectus supplement, in an amendment to the registration statement of which this prospectus is a part, or in other filings we make with the SEC under the Exchange Act, which are incorporated by reference.

Unless the applicable prospectus supplement indicates otherwise, the validity of the securities offered hereby will be passed upon for us by Bradley Arant Boult Cummings LLP. Additional legal matters may be passed upon for us or any underwriters, dealers or agents by counsel that we will name in the applicable prospectus supplement.

The consolidated financial statements of Momentus Inc. as of and for the years ended December 31, 2021 and 2020, and for each of the two years in the period ended December 31, 2021, of Momentus Inc. incorporated by reference in this prospectus have been audited by Armanino LLP, an independent registered public accounting firm, as stated in their report incorporated by reference herein. Such financial statements have been so incorporated by reference in reliance upon the report of such firm given upon their authority as experts in accounting and auditing.

We are required to file annual, quarterly and current reports, proxy statements and other information with the SEC as required by the Exchange Act. You can read our SEC filings, including this prospectus, over the Internet at the SEC’s website at www.sec.gov. Those filings are also available to the public on, or accessible through, our website at investors.momentus.space. The information we file with the SEC or contained on or accessible through our corporate website or any other website that we may maintain is not part of this prospectus and any prospectus supplement, or the registration statement of which this prospectus is a part. You may inspect a copy of the registration statement through the SEC’s website, as provided herein.

This prospectus and any prospectus supplement are part of a registration statement that we filed with the SEC and do not contain all of the information in the registration statement. The full registration statement may be obtained from the SEC or us, as provided above. Forms of documents establishing the terms of any offered securities are or may be filed as exhibits to the registration statement or documents incorporated by reference in the registration statement. Statements in this prospectus or any prospectus supplement about these documents are summaries and each statement is qualified in all respects by reference to the document to which it refers. You should refer to the actual documents for a more complete description of the relevant matters. You may inspect a copy of the registration statement through the SEC’s website, as provided above.