TABLE OF CONTENTS As filed with the Securities and Exchange Commission on December 19, 2025. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 MOMENTUS INC. (Exact Name of Registrant as Specified in Its Charter) (State or Other Jurisdiction of Incorporation or Organization) (Primary Standard Industrial Classification Code Number) Delaware 3714 84-1905538 (I.R.S. Employer Identification Number) 3901 N ...

TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 MOMENTUS INC. (Exact Name of Registrant as Specified in Its Charter) (State or Other Jurisdiction of Incorporation or Organization) (Primary Standard Industrial Classification Code Number) As filed with the Securities and Exchange Commission on October 24, 2025. Registration No. 333- If this Form is filed to register additional securities for an offering ...