3.26.1 html 637 552 1 false 139 0 false 13 false false R1.htm 0000001 - Document - Cover Page Sheet http://momentus.space/role/CoverPage Cover Page Cover 1 false false R2.htm 0000002 - Document - Audit Information Sheet http://momentus.space/role/AuditInformation Audit Information Cover 2 false false R3.htm 9952151 - Statement - CONSOLIDATED BALANCE SHEETS Sheet http://momentus.space/role/CONSOLIDATEDBALANCESHEETS CONSOLIDATED BALANCE SHEETS Statements 3 false false R4.htm 9952152 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical) Sheet http://momentus.space/role/CONSOLIDATEDBALANCESHEETSParenthetical CONSOLIDATED BALANCE SHEETS (Parenthetical) Statements 4 false false R5.htm 9952153 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS Sheet http://momentus.space/role/CONSOLIDATEDSTATEMENTSOFOPERATIONS CONSOLIDATED STATEMENTS OF OPERATIONS Statements 5 false false R6.htm 9952154 - Statement - CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) Sheet http://momentus.space/role/CONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITYDEFICIT CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) Statements 6 false false R7.htm 9952155 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS Sheet http://momentus.space/role/CONSOLIDATEDSTATEMENTSOFCASHFLOWS CONSOLIDATED STATEMENTS OF CASH FLOWS Statements 7 false false R8.htm 9952156 - Disclosure - Nature of Operations Sheet http://momentus.space/role/NatureofOperations Nature of Operations Notes 8 false false R9.htm 9952157 - Disclosure - Summary of Significant Accounting Policies Sheet http://momentus.space/role/SummaryofSignificantAccountingPolicies Summary of Significant Accounting Policies Notes 9 false false R10.htm 9952158 - Disclosure - Prepaids and Other Current Assets Sheet http://momentus.space/role/PrepaidsandOtherCurrentAssets Prepaids and Other Current Assets Notes 10 false false R11.htm 9952159 - Disclosure - Property, Machinery and Equipment Sheet http://momentus.space/role/PropertyMachineryandEquipment Property, Machinery and Equipment Notes 11 false false R12.htm 9952160 - Disclosure - Intangible Assets Sheet http://momentus.space/role/IntangibleAssets Intangible Assets Notes 12 false false R13.htm 9952161 - Disclosure - Leases Sheet http://momentus.space/role/Leases Leases Notes 13 false false R14.htm 9952162 - Disclosure - Accrued Liabilities Sheet http://momentus.space/role/AccruedLiabilities Accrued Liabilities Notes 14 false false R15.htm 9952163 - Disclosure - Loan Payable Sheet http://momentus.space/role/LoanPayable Loan Payable Notes 15 false false R16.htm 9952164 - Disclosure - Stockholders' Equity (Deficit) Sheet http://momentus.space/role/StockholdersEquityDeficit Stockholders' Equity (Deficit) Notes 16 false false R17.htm 9952165 - Disclosure - Stock-based Compensation Sheet http://momentus.space/role/StockbasedCompensation Stock-based Compensation Notes 17 false false R18.htm 9952166 - Disclosure - Net Loss Per Share Sheet http://momentus.space/role/NetLossPerShare Net Loss Per Share Notes 18 false false R19.htm 9952167 - Disclosure - Commitment and Contingencies Sheet http://momentus.space/role/CommitmentandContingencies Commitment and Contingencies Notes 19 false false R20.htm 9952168 - Disclosure - Income Taxes Sheet http://momentus.space/role/IncomeTaxes Income Taxes Notes 20 false false R21.htm 9952169 - Disclosure - Related Party Transactions Sheet http://momentus.space/role/RelatedPartyTransactions Related Party Transactions Notes 21 false false R22.htm 9952170 - Disclosure - Segment Information Sheet http://momentus.space/role/SegmentInformation Segment Information Notes 22 false false R23.htm 9952171 - Disclosure - Supplemental Disclosures for Consolidated Statements of Cash Flows Sheet http://momentus.space/role/SupplementalDisclosuresforConsolidatedStatementsofCashFlows Supplemental Disclosures for Consolidated Statements of Cash Flows Notes 23 false false R24.htm 9952172 - Disclosure - Subsequent Events Sheet http://momentus.space/role/SubsequentEvents Subsequent Events Notes 24 false false R25.htm 995445 - Disclosure - Insider Trading Arrangements Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements Insider Trading Arrangements Notes 25 false false R26.htm 995447 - Disclosure - Insider Trading Policies and Procedures Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc Insider Trading Policies and Procedures Notes 26 false false R27.htm 995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure Sheet http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure Cybersecurity Risk Management and Strategy Disclosure Notes 27 false false R28.htm 9955511 - Disclosure - Summary of Significant Accounting Policies (Policies) Sheet http://momentus.space/role/SummaryofSignificantAccountingPoliciesPolicies Summary of Significant Accounting Policies (Policies) Policies http://momentus.space/role/SummaryofSignificantAccountingPolicies 28 false false R29.htm 9955512 - Disclosure - Summary of Significant Accounting Policies (Tables) Sheet http://momentus.space/role/SummaryofSignificantAccountingPoliciesTables Summary of Significant Accounting Policies (Tables) Tables http://momentus.space/role/SummaryofSignificantAccountingPolicies 29 false false R30.htm 9955513 - Disclosure - Prepaids and Other Current Assets (Tables) Sheet http://momentus.space/role/PrepaidsandOtherCurrentAssetsTables Prepaids and Other Current Assets (Tables) Tables http://momentus.space/role/PrepaidsandOtherCurrentAssets 30 false false R31.htm 9955514 - Disclosure - Property, Machinery and Equipment (Tables) Sheet http://momentus.space/role/PropertyMachineryandEquipmentTables Property, Machinery and Equipment (Tables) Tables http://momentus.space/role/PropertyMachineryandEquipment 31 false false R32.htm 9955515 - Disclosure - Intangible Assets (Tables) Sheet http://momentus.space/role/IntangibleAssetsTables Intangible Assets (Tables) Tables http://momentus.space/role/IntangibleAssets 32 false false R33.htm 9955516 - Disclosure - Leases (Tables) Sheet http://momentus.space/role/LeasesTables Leases (Tables) Tables http://momentus.space/role/Leases 33 false false R34.htm 9955517 - Disclosure - Accrued Liabilities (Tables) Sheet http://momentus.space/role/AccruedLiabilitiesTables Accrued Liabilities (Tables) Tables http://momentus.space/role/AccruedLiabilities 34 false false R35.htm 9955518 - Disclosure - Loan Payable (Tables) Sheet http://momentus.space/role/LoanPayableTables Loan Payable (Tables) Tables http://momentus.space/role/LoanPayable 35 false false R36.htm 9955519 - Disclosure - Stockholders' Equity (Deficit) (Tables) Sheet http://momentus.space/role/StockholdersEquityDeficitTables Stockholders' Equity (Deficit) (Tables) Tables http://momentus.space/role/StockholdersEquityDeficit 36 false false R37.htm 9955520 - Disclosure - Stock-based Compensation (Tables) Sheet http://momentus.space/role/StockbasedCompensationTables Stock-based Compensation (Tables) Tables http://momentus.space/role/StockbasedCompensation 37 false false R38.htm 9955521 - Disclosure - Net Loss Per Share (Tables) Sheet http://momentus.space/role/NetLossPerShareTables Net Loss Per Share (Tables) Tables http://momentus.space/role/NetLossPerShare 38 false false R39.htm 9955522 - Disclosure - Commitment and Contingencies (Tables) Sheet http://momentus.space/role/CommitmentandContingenciesTables Commitment and Contingencies (Tables) Tables http://momentus.space/role/CommitmentandContingencies 39 false false R40.htm 9955523 - Disclosure - Income Taxes (Tables) Sheet http://momentus.space/role/IncomeTaxesTables Income Taxes (Tables) Tables http://momentus.space/role/IncomeTaxes 40 false false R41.htm 9955524 - Disclosure - Segment Information (Tables) Sheet http://momentus.space/role/SegmentInformationTables Segment Information (Tables) Tables http://momentus.space/role/SegmentInformation 41 false false R42.htm 9955525 - Disclosure - Supplemental Disclosures for Consolidated Statements of Cash Flows (Tables) Sheet http://momentus.space/role/SupplementalDisclosuresforConsolidatedStatementsofCashFlowsTables Supplemental Disclosures for Consolidated Statements of Cash Flows (Tables) Tables http://momentus.space/role/SupplementalDisclosuresforConsolidatedStatementsofCashFlows 42 false false R43.htm 9955526 - Disclosure - Nature of Operations (Details) Sheet http://momentus.space/role/NatureofOperationsDetails Nature of Operations (Details) Details http://momentus.space/role/NatureofOperations 43 false false R44.htm 9955527 - Disclosure - Summary of Significant Accounting Policies - Narrative (Details) Sheet http://momentus.space/role/SummaryofSignificantAccountingPoliciesNarrativeDetails Summary of Significant Accounting Policies - Narrative (Details) Details 44 false false R45.htm 9955528 - Disclosure - Summary of Significant Accounting Policies - Schedule of Property, Machinery and Equipment, net (Details) Sheet http://momentus.space/role/SummaryofSignificantAccountingPoliciesScheduleofPropertyMachineryandEquipmentnetDetails Summary of Significant Accounting Policies - Schedule of Property, Machinery and Equipment, net (Details) Details 45 false false R46.htm 9955529 - Disclosure - Summary of Significant Accounting Policies - Schedule of Disaggregation of Revenue (Details) Sheet http://momentus.space/role/SummaryofSignificantAccountingPoliciesScheduleofDisaggregationofRevenueDetails Summary of Significant Accounting Policies - Schedule of Disaggregation of Revenue (Details) Details 46 false false R47.htm 9955530 - Disclosure - Summary of Significant Accounting Policies - Schedule of Changes in Fair Value of Assets and Liabilities (Details) Sheet http://momentus.space/role/SummaryofSignificantAccountingPoliciesScheduleofChangesinFairValueofAssetsandLiabilitiesDetails Summary of Significant Accounting Policies - Schedule of Changes in Fair Value of Assets and Liabilities (Details) Details 47 false false R48.htm 9955531 - Disclosure - Summary of Significant Accounting Policies - Schedule of Fair Value Inputs (Details) Sheet http://momentus.space/role/SummaryofSignificantAccountingPoliciesScheduleofFairValueInputsDetails Summary of Significant Accounting Policies - Schedule of Fair Value Inputs (Details) Details 48 false false R49.htm 9955532 - Disclosure - Prepaids and Other Current Assets (Details) Sheet http://momentus.space/role/PrepaidsandOtherCurrentAssetsDetails Prepaids and Other Current Assets (Details) Details http://momentus.space/role/PrepaidsandOtherCurrentAssetsTables 49 false false R50.htm 9955533 - Disclosure - Property, Machinery and Equipment (Details) Sheet http://momentus.space/role/PropertyMachineryandEquipmentDetails Property, Machinery and Equipment (Details) Details http://momentus.space/role/PropertyMachineryandEquipmentTables 50 false false R51.htm 9955534 - Disclosure - Intangible Assets - Schedule of Intangible Assets, Net (Details) Sheet http://momentus.space/role/IntangibleAssetsScheduleofIntangibleAssetsNetDetails Intangible Assets - Schedule of Intangible Assets, Net (Details) Details 51 false false R52.htm 9955535 - Disclosure - Intangible Assets - Narrative (Details) Sheet http://momentus.space/role/IntangibleAssetsNarrativeDetails Intangible Assets - Narrative (Details) Details 52 false false R53.htm 9955536 - Disclosure - Intangible Assets - Schedule of Future Estimated Amortization Expense (Details) Sheet http://momentus.space/role/IntangibleAssetsScheduleofFutureEstimatedAmortizationExpenseDetails Intangible Assets - Schedule of Future Estimated Amortization Expense (Details) Details 53 false false R54.htm 9955537 - Disclosure - Leases - Schedule of Components of Operating Lease Expense (Details) Sheet http://momentus.space/role/LeasesScheduleofComponentsofOperatingLeaseExpenseDetails Leases - Schedule of Components of Operating Lease Expense (Details) Details 54 false false R55.htm 9955538 - Disclosure - Leases - Narrative (Details) Sheet http://momentus.space/role/LeasesNarrativeDetails Leases - Narrative (Details) Details 55 false false R56.htm 9955539 - Disclosure - Leases - Schedule of Maturities of Operating Lease Liabilities (Details) Sheet http://momentus.space/role/LeasesScheduleofMaturitiesofOperatingLeaseLiabilitiesDetails Leases - Schedule of Maturities of Operating Lease Liabilities (Details) Details 56 false false R57.htm 9955540 - Disclosure - Accrued Liabilities (Details) Sheet http://momentus.space/role/AccruedLiabilitiesDetails Accrued Liabilities (Details) Details http://momentus.space/role/AccruedLiabilitiesTables 57 false false R58.htm 9955541 - Disclosure - Loan Payable - September 2025 Convertible Note and AIR Warrants (Details) Sheet http://momentus.space/role/LoanPayableSeptember2025ConvertibleNoteandAIRWarrantsDetails Loan Payable - September 2025 Convertible Note and AIR Warrants (Details) Details 58 false false R59.htm 9955542 - Disclosure - Loan Payable - Schedule of Fair Value Inputs (Details) Sheet http://momentus.space/role/LoanPayableScheduleofFairValueInputsDetails Loan Payable - Schedule of Fair Value Inputs (Details) Details 59 false false R60.htm 9955543 - Disclosure - Loan Payable - May 2025 Loan (Details) Sheet http://momentus.space/role/LoanPayableMay2025LoanDetails Loan Payable - May 2025 Loan (Details) Details 60 false false R61.htm 9955544 - Disclosure - Loan Payable - AGP Convertible Promissory Note (Details) Sheet http://momentus.space/role/LoanPayableAGPConvertiblePromissoryNoteDetails Loan Payable - AGP Convertible Promissory Note (Details) Details 61 false false R62.htm 9955545 - Disclosure - Loan Payable - December 2024 Loan (Details) Sheet http://momentus.space/role/LoanPayableDecember2024LoanDetails Loan Payable - December 2024 Loan (Details) Details 62 false false R63.htm 9955546 - Disclosure - Loan Payable - SIV Convertible Promissory Notes (Details) Notes http://momentus.space/role/LoanPayableSIVConvertiblePromissoryNotesDetails Loan Payable - SIV Convertible Promissory Notes (Details) Details 63 false false R64.htm 9955547 - Disclosure - Loan Payable - Term Loan (Details) Sheet http://momentus.space/role/LoanPayableTermLoanDetails Loan Payable - Term Loan (Details) Details 64 false false R65.htm 9955548 - Disclosure - Stockholders' Equity (Deficit) - Common Stock and Preferred Stock (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitCommonStockandPreferredStockDetails Stockholders' Equity (Deficit) - Common Stock and Preferred Stock (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 65 false false R66.htm 9955549 - Disclosure - Stockholders' Equity (Deficit) - Shares Issued in Settlement of Accounts Payable and Customer Deposits (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitSharesIssuedinSettlementofAccountsPayableandCustomerDepositsDetails Stockholders' Equity (Deficit) - Shares Issued in Settlement of Accounts Payable and Customer Deposits (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 66 false false R67.htm 9955550 - Disclosure - Stockholders' Equity (Deficit) - Schedule of Fair Value Inputs (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitScheduleofFairValueInputsDetails Stockholders' Equity (Deficit) - Schedule of Fair Value Inputs (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 67 false false R68.htm 9955551 - Disclosure - Stockholders' Equity (Deficit) - December 2025 Warrant Inducement (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitDecember2025WarrantInducementDetails Stockholders' Equity (Deficit) - December 2025 Warrant Inducement (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 68 false false R69.htm 9955552 - Disclosure - Stockholders' Equity (Deficit) - October 2025 Warrant Inducement Agreement (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitOctober2025WarrantInducementAgreementDetails Stockholders' Equity (Deficit) - October 2025 Warrant Inducement Agreement (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 69 false false R70.htm 9955553 - Disclosure - Stockholders' Equity (Deficit) - Baker & McKenzie LLP settlement (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitBakerMcKenzieLLPsettlementDetails Stockholders' Equity (Deficit) - Baker & McKenzie LLP settlement (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 70 false false R71.htm 9955554 - Disclosure - Stockholders' Equity (Deficit) - September 2025 Equity Line of Credit (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitSeptember2025EquityLineofCreditDetails Stockholders' Equity (Deficit) - September 2025 Equity Line of Credit (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 71 false false R72.htm 9955555 - Disclosure - Stockholders' Equity (Deficit) - At-The-Market Offering (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitAtTheMarketOfferingDetails Stockholders' Equity (Deficit) - At-The-Market Offering (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 72 false false R73.htm 9955556 - Disclosure - Stockholders' Equity (Deficit) - August 2025 Warrant Inducement (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitAugust2025WarrantInducementDetails Stockholders' Equity (Deficit) - August 2025 Warrant Inducement (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 73 false false R74.htm 9955557 - Disclosure - Stockholders' Equity (Deficit) - July 2025 Public Offering (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitJuly2025PublicOfferingDetails Stockholders' Equity (Deficit) - July 2025 Public Offering (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 74 false false R75.htm 9955558 - Disclosure - Stockholders' Equity (Deficit) - Master Services Agreement (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitMasterServicesAgreementDetails Stockholders' Equity (Deficit) - Master Services Agreement (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 75 false false R76.htm 9955559 - Disclosure - Stockholders' Equity (Deficit) - March 2025 Warrant Inducement (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitMarch2025WarrantInducementDetails Stockholders' Equity (Deficit) - March 2025 Warrant Inducement (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 76 false false R77.htm 9955560 - Disclosure - Stockholders' Equity (Deficit) - February 2025 Public Offering (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitFebruary2025PublicOfferingDetails Stockholders' Equity (Deficit) - February 2025 Public Offering (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 77 false false R78.htm 9955561 - Disclosure - Stockholders' Equity (Deficit) - December 2024 Securities Purchase Agreement (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitDecember2024SecuritiesPurchaseAgreementDetails Stockholders' Equity (Deficit) - December 2024 Securities Purchase Agreement (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 78 false false R79.htm 9955562 - Disclosure - Stockholders' Equity (Deficit) - September 2024 Securities Purchase Agreement (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitSeptember2024SecuritiesPurchaseAgreementDetails Stockholders' Equity (Deficit) - September 2024 Securities Purchase Agreement (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 79 false false R80.htm 9955563 - Disclosure - Stockholders' Equity (Deficit) - Cashless Exercise of Warrants (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitCashlessExerciseofWarrantsDetails Stockholders' Equity (Deficit) - Cashless Exercise of Warrants (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 80 false false R81.htm 9955564 - Disclosure - Stockholders' Equity (Deficit) - March 2024 Securities Purchase Agreement (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitMarch2024SecuritiesPurchaseAgreementDetails Stockholders' Equity (Deficit) - March 2024 Securities Purchase Agreement (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 81 false false R82.htm 9955565 - Disclosure - Stockholders' Equity (Deficit) - January 2024 Securities Purchase Agreement (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitJanuary2024SecuritiesPurchaseAgreementDetails Stockholders' Equity (Deficit) - January 2024 Securities Purchase Agreement (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 82 false false R83.htm 9955566 - Disclosure - Stockholders' Equity (Deficit) - Public and Private Warrants (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitPublicandPrivateWarrantsDetails Stockholders' Equity (Deficit) - Public and Private Warrants (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 83 false false R84.htm 9955567 - Disclosure - Stockholders' Equity (Deficit) - Contingent Sponsor Earnout Shares (Details) Sheet http://momentus.space/role/StockholdersEquityDeficitContingentSponsorEarnoutSharesDetails Stockholders' Equity (Deficit) - Contingent Sponsor Earnout Shares (Details) Details http://momentus.space/role/StockholdersEquityDeficitTables 84 false false R85.htm 9955568 - Disclosure - Stock-based Compensation - Narrative (Details) Sheet http://momentus.space/role/StockbasedCompensationNarrativeDetails Stock-based Compensation - Narrative (Details) Details 85 false false R86.htm 9955569 - Disclosure - Stock-based Compensation - Schedule of Options Activity (Details) Sheet http://momentus.space/role/StockbasedCompensationScheduleofOptionsActivityDetails Stock-based Compensation - Schedule of Options Activity (Details) Details 86 false false R87.htm 9955570 - Disclosure - Stock-based Compensation - Schedule of Restricted Stock Units Activity (Details) Sheet http://momentus.space/role/StockbasedCompensationScheduleofRestrictedStockUnitsActivityDetails Stock-based Compensation - Schedule of Restricted Stock Units Activity (Details) Details 87 false false R88.htm 9955571 - Disclosure - Stock-based Compensation - Schedule of Stock-Based Compensation Expense (Details) Sheet http://momentus.space/role/StockbasedCompensationScheduleofStockBasedCompensationExpenseDetails Stock-based Compensation - Schedule of Stock-Based Compensation Expense (Details) Details 88 false false R89.htm 9955572 - Disclosure - Net Loss Per Share (Details) Sheet http://momentus.space/role/NetLossPerShareDetails Net Loss Per Share (Details) Details http://momentus.space/role/NetLossPerShareTables 89 false false R90.htm 9955573 - Disclosure - Commitment and Contingencies - Schedule of Unconditional Purchase Obligations (Details) Sheet http://momentus.space/role/CommitmentandContingenciesScheduleofUnconditionalPurchaseObligationsDetails Commitment and Contingencies - Schedule of Unconditional Purchase Obligations (Details) Details 90 false false R91.htm 9955574 - Disclosure - Commitment and Contingencies - Narrative (Details) Sheet http://momentus.space/role/CommitmentandContingenciesNarrativeDetails Commitment and Contingencies - Narrative (Details) Details 91 false false R92.htm 9955575 - Disclosure - Income Taxes - Schedule of Income before Income Tax, Domestic and Foreign (Details) Sheet http://momentus.space/role/IncomeTaxesScheduleofIncomebeforeIncomeTaxDomesticandForeignDetails Income Taxes - Schedule of Income before Income Tax, Domestic and Foreign (Details) Details 92 false false R93.htm 9955576 - Disclosure - Income Taxes - Reconciliation of Nondeductible Expenses (Details) Sheet http://momentus.space/role/IncomeTaxesReconciliationofNondeductibleExpensesDetails Income Taxes - Reconciliation of Nondeductible Expenses (Details) Details 93 false false R94.htm 9955577 - Disclosure - Income Taxes - Schedule of Reconciliation of Effective Income Tax Rate (Details) Sheet http://momentus.space/role/IncomeTaxesScheduleofReconciliationofEffectiveIncomeTaxRateDetails Income Taxes - Schedule of Reconciliation of Effective Income Tax Rate (Details) Details 94 false false R95.htm 9955578 - Disclosure - Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) Sheet http://momentus.space/role/IncomeTaxesScheduleofDeferredTaxAssetsandLiabilitiesDetails Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) Details 95 false false R96.htm 9955579 - Disclosure - Income Taxes - Narrative (Details) Sheet http://momentus.space/role/IncomeTaxesNarrativeDetails Income Taxes - Narrative (Details) Details 96 false false R97.htm 9955580 - Disclosure - Related Party Transactions (Details) Sheet http://momentus.space/role/RelatedPartyTransactionsDetails Related Party Transactions (Details) Details http://momentus.space/role/RelatedPartyTransactions 97 false false R98.htm 9955581 - Disclosure - Segment Information (Details) Sheet http://momentus.space/role/SegmentInformationDetails Segment Information (Details) Details http://momentus.space/role/SegmentInformationTables 98 false false R99.htm 9955582 - Disclosure - Supplemental Disclosures for Consolidated Statements of Cash Flows (Details) Sheet http://momentus.space/role/SupplementalDisclosuresforConsolidatedStatementsofCashFlowsDetails Supplemental Disclosures for Consolidated Statements of Cash Flows (Details) Details http://momentus.space/role/SupplementalDisclosuresforConsolidatedStatementsofCashFlowsTables 99 false false R100.htm 9955583 - Disclosure - Subsequent Events (Details) Sheet http://momentus.space/role/SubsequentEventsDetails Subsequent Events (Details) Details http://momentus.space/role/SubsequentEvents 100 false false All Reports Book All Reports mnts-20251231.htm mnts-20251231.xsd mnts-20251231_cal.xml mnts-20251231_def.xml mnts-20251231_lab.xml mnts-20251231_pre.xml http://fasb.org/us-gaap/2025 http://xbrl.sec.gov/cyd/2025 http://xbrl.sec.gov/dei/2025 http://xbrl.sec.gov/ecd/2025 true true