Sec Form 4 Filing - Prime Movers Lab Fund I LP @ Momentus Inc. - 2021-08-12

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Prime Movers Lab Fund I LP 2. Issuer Name and Ticker or Trading Symbol Momentus Inc. [ MNTS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) P.O. BOX 12829 3. Date of Earliest Transaction (MM/DD/YY) 08/12/2021 (Street) JACKSON, WY83002 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A Common Stock 08/12/2021 A 14,905,597 A 14,905,597 D ( 2 ) Class A Common Stock 08/12/2021 A 1,000,000 A 15,905,597 D ( 2 ) Class A Common Stock 08/12/2021 A 6,373,200 A 6,373,200 I By Momentus PML SPV 1 LP ( 2 ) Class A Common Stock 08/12/2021 A 1,018,594 A 1,018,594 I By Momentus PML SPV 2 LP ( 2 ) Class A Common Stock 08/12/2021 A 2,526,394 A 2,526,394 I By Momentus PML SPV 3 LP ( 2 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7 . Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Warrants (right to buy) $ 11.5 08/12/2021 A 1,000,000 ( 4 ) ( 4 ) Class A Common Stock 1,000,000 ( 4 ) 1,000,000 D ( 2 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Prime Movers Lab Fund I LP P.O. BOX 12829 JACKSON, WY83002 X Momentus PML SPV 1 LP P.O. BOX 12829 JACKSON, WY83002 X MOMENTUS PML SPV 2 LP P.O. BOX 12829 JACKSON, WY83002 X Momentus PML SPV 3 LP P.O. BOX 12829 JACKSON, WY83002 X Signatures /s/ Jon Layman, Authorized Person on behalf of the General Partner of each Reporting Person 08/16/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On August 12, 2021, pursuant to that certain Agreement and Plan of Merger, dated as of October 7, 2020 (as amended, supplemented or modified from time to time, the "Merger Agreement"), by and among Stable Road Acquisition Corp., a Delaware corporation (the "Issuer"), Momentus Inc., a Delaware corporation ("Legacy Momentus"), and the other parties thereto, the Issuer completed its initial business combination (the "Business Combination"). As a result of the Business Combination, the Issuer changed its name to Momentus Inc. In connection with the Business Combination and in accordance with the Merger Agreement, an aggregate of 65,133,131 shares of Class A Common Stock of Legacy Momentus held by the Reporting Person were converted into 14,905,597 shares of Class A Common Stock of the Issuer. The issuance of the shares was approved by the Issuer's board of directors pursuant to Rule 16b-3 under the Securities Exchange Act of 1934, as amended. ( 2 )Prime Movers Lab GP I LLC is the general partner of each of the Reporting Persons. ( 3 )Pursuant to a Subscription Agreement dated as of July 16, 2021 (as amended from time to time, the "Subscription Agreement") entered into in connection with the Business Combination Agreement, the Reporting Person agreed to subscribe for and purchase, in a private placement immediately prior to the closing of the Business Combination, an aggregate of 1,000,000 shares of Class A Common Stock of the Issuer for a purchase price of $10.00 per share. ( 4 )Pursuant to the Subscription Agreement, the Reporting Person received a warrant to purchase one share of Class A Common Stock of the Issuer at a price of $11.50 per share (subject to adjustment as described in the warrant agreement) for each share of Class A Common Stock of the Issuer purchased by the Reporting Person.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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