v3.26.1
Cover Page - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Mar. 27, 2026
Document Information [Line Items]    
Document Type 10-K  
Document Annual Report true  
Document Period End Date Dec. 31, 2025  
Current Fiscal Year End Date --12-31  
Document Transition Report false  
Entity File Number 001-39128  
Entity Registrant Name Momentus Inc.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 84-1905538  
Entity Address, Address Line One 1762 Automation Parkway  
Entity Address, City or Town San Jose  
Entity Address, State or Province CA  
Entity Address, Postal Zip Code 95131  
City Area Code 650  
Local Phone Number 564-7820  
Entity Well-known Seasoned Issuer No  
Entity Voluntary Filers No  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Smaller Reporting Company true  
Emerging Growth Company false  
ICFR Auditor Attestation Flag false  
Document Financial Statement Error Correction false  
Entity Shell Company false  
Entity Public Float $ 13.2  
Entity Common Stock, Shares Outstanding   5,730,006
Documents Incorporated by Reference
Portions of the registrant’s definitive proxy statement for its 2026 annual stockholders’ meeting are incorporated by reference in Part III of this report. The registrant’s definitive proxy statement will be filed with the U.S. Securities and Exchange Commission within 120 days after December 31, 2025.
  
Entity Central Index Key 0001781162  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus FY  
Amendment Flag false  
Common stock – Class A    
Document Information [Line Items]    
Title of 12(b) Security Class A common stock  
Trading Symbol MNTS  
Security Exchange Name NASDAQ  
Warrants    
Document Information [Line Items]    
Title of 12(b) Security Warrants  
Trading Symbol MNTSW  
Security Exchange Name NASDAQ