v3.26.1
Cover Page - shares
 3 Months Ended
Mar. 31, 2026
May 13, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2026  
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 Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Smaller Reporting Company true  
Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   9,992,398
Entity Central Index Key 0001781162  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q1  
Amendment Flag false  
Current Fiscal Year End Date --12-31  
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