Subsequent Events	6 Months Ended
Jun. 30, 2024
Subsequent Events [Abstract]
Subsequent Events	Note 15. Subsequent Events Convertible Promissory Note On July 12, 2024, the Company and Space Infrastructure Ventures (“SIV”) entered into a secured convertible promissory note (the “Convertible Note”) pursuant to which the Company borrowed $2.3 million as of September 26, 2024. The Convertible Note bears an annual interest rate of 15%. Principal on the Convertible Note is to be re-paid in four equal payments on a quarterly basis, commencing on December 1, 2024, and maturing on September 1, 2025, at which time all accrued interest is due. Amounts borrowed under the Convertible Note are secured by a lien on substantially all of the assets of the Company. In lieu of cash payments of accrued interest, SIV, in its sole discretion, may elect to receive shares of Class A common stock at a conversion price of $0.53 per share (the “Conversion Price”). On the maturity date, subject to the satisfaction of applicable legal and regulatory conditions, all outstanding obligations under the Convertible Note automatically convert into Class A common stock at the Conversion Price. The Convertible Note requires SIV’s consent to take certain actions, such as increasing compensation, purchasing assets, extending financing, making capital expenditures, repaying debts outside the ordinary course of business or investing in any entity or enterprise. The Convertible Note can be prepaid in full at any time, subject to a prepayment penalty fee of 10%. The Convertible Note will accelerate and become immediately due upon the occurrence of certain customary events of default, including failure to pay amounts owing when due and/or certain events involving a discontinuation of our business or certain types of proceedings involving insolvency, bankruptcy, receivership and the like, or a change of control of Momentus. Indemnification Claims On July 31, 2024, certain former employees of the Company obtained a legal judgment in the amount of $526 thousand inclusive of interest and expenses related to claims for the advancement and reimbursement of certain legal expenses of the former employees. The Company paid the former employees $526 thousand inclusive of interest and expenses related to claims for the advancement and reimbursement of certain legal expenses of the former employees in September 2024. Venture-Class Acquisition of Dedicated Rideshare Contract On August 22, 2024, NASA selected the Company to participate as a launch provider in the Venture-Class Acquisition of Dedicated Rideshare (“VADR”) contract. The VADR program is anticipated to allow NASA to deliver Class D, CubeSats, and higher risk-tolerant payloads to a variety of orbits. The Company executed the VADR contract with NASA on August 19, 2024. Settlement of Derivative Litigation On August 26, 2024, an unopposed motion for the preliminary approval of settlement was filed after the Company reached an agreement in principle for a proposed settlement of certain shareholder derivative litigation. The proposed settlement, as set forth more fully in the Stipulation and Agreement of Settlement filed with the court, requires the Company to adopt certain corporate governance reforms. The reforms must be maintained for a minimum period of four years. On September 16, 2024, the U.S. District Court for the Northern District of California issued an order primarily approving the settlement and providing for notice of the settlement to stockholders of the Company in the matters captioned Hanna v. Kabot, et al., Case No. 5:23-cv-00374 (N.D. Cal.); Rivlen v. Kabot, et al., Case No. 2:23-cv-03120 (C.D. Cal.); Lindsey v. Quiroga, et al., Case No. 20230674 (Del. Ch.); and the litigation demand made by Momentus stockholder, Kamal Qureshi (collectively, the “Derivative Matters”). The proposed settlement calls for the Company to adopt certain corporate governance reforms and pay lead plaintiffs’ attorney’s fees, litigation expenses, and lead plaintiff service awards. The order set a final approval hearing for November 21, 2024. September 2024 Securities Purchase Agreement On September 15, 2024, the Company entered into a Securities Purchase Agreement with an investor, pursuant to which the Company issued and sold to an investor in a private placement transaction (the “September Offering”), (i) pre-funded warrants to purchase 5,000,000 shares of the Company’s Class A common stock at a purchase price of $0.55 per share (the “September Pre-Funded Warrants”), (ii) Class A warrants to purchase 10,000,000 shares of Class A common stock (the “Class A Warrants”), and (iii) Class B warrants to purchase 5,000,000 shares of Class A common stock (the “Class B Warrants” and, collectively with the Class A Warrants, the “September Warrants”). The Company received aggregate gross proceeds of approximately $2.75 million, before deducting estimated placement agent commissions and expenses. The offering closed on September 17, 2024. The September Pre-Funded Warrants have an exercise price of $0.00001 per share and are exercisable any time after issuance and will not expire until exercised. The September Warrants have an exercise price per share of Class A common stock equal to $0.575 per share. The Class A Warrants will expire on March 17, 2030, and the Class B Warrants will expire on March 17, 2026. The exercise price and the number of shares of Class A common stock issuable upon exercise of the September Warrants is subject to appropriate adjustments in the event of certain stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events affecting the Class A common stock. The investor may not exercise the September Warrants until 6 months after the original issuance date of the September Warrants. In connection with the September Offering, the Company entered into a Placement Agency Agreement on September 15, 2024, with the agency which assisted with the transaction. The Company paid a cash placement agent commission equal to 7.0% of gross proceeds from the September Offering and issued warrants (the “Placement Agent Warrants”) to purchase 500,000 shares of Class A common stock at an exercise price of $0.6325, exercisable immediately, as compensation for services. One half of the Placement Agent Warrants have a term of 18 months from the date of issuance and the other half have a term of five years from the date of issuance.

On July 12, 2024, the Company and Space Infrastructure Ventures (“SIV”) entered into a secured convertible promissory note (the “Convertible Note”) pursuant to which the Company borrowed $2.3 million as of September 26, 2024. The Convertible Note bears an annual interest rate of 15%. Principal on the Convertible Note is to be re-paid in four equal payments on a quarterly basis, commencing on December 1, 2024, and maturing on September 1, 2025, at which time all accrued interest is due.

Amounts borrowed under the Convertible Note are secured by a lien on substantially all of the assets of the Company. In lieu of cash payments of accrued interest, SIV, in its sole discretion, may elect to receive shares of Class A common stock at a conversion price of $0.53 per share (the “Conversion Price”). On the maturity date, subject to the satisfaction of applicable legal and regulatory conditions, all outstanding obligations under the Convertible Note automatically convert into Class A common stock at the Conversion Price.

The Convertible Note requires SIV’s consent to take certain actions, such as increasing compensation, purchasing assets, extending financing, making capital expenditures, repaying debts outside the ordinary course of business or investing in any entity or enterprise.

The Convertible Note can be prepaid in full at any time, subject to a prepayment penalty fee of 10%. The Convertible Note will accelerate and become immediately due upon the occurrence of certain customary events of default, including failure to pay amounts owing when due and/or certain events involving a discontinuation of our business or certain types of proceedings involving insolvency, bankruptcy, receivership and the like, or a change of control of Momentus.

On July 31, 2024, certain former employees of the Company obtained a legal judgment in the amount of $526 thousand inclusive of interest and expenses related to claims for the advancement and reimbursement of certain legal expenses of the former employees. The Company paid the former employees $526 thousand inclusive of interest and

On August 22, 2024, NASA selected the Company to participate as a launch provider in the Venture-Class Acquisition of Dedicated Rideshare (“VADR”) contract. The VADR program is anticipated to allow NASA to deliver Class D, CubeSats, and higher risk-tolerant payloads to a variety of orbits. The Company executed the VADR contract with NASA on August 19, 2024.

On August 26, 2024, an unopposed motion for the preliminary approval of settlement was filed after the Company reached an agreement in principle for a proposed settlement of certain shareholder derivative litigation. The proposed settlement, as set forth more fully in the Stipulation and Agreement of Settlement filed with the court, requires the Company to adopt certain corporate governance reforms. The reforms must be maintained for a minimum period of four years.

On September 16, 2024, the U.S. District Court for the Northern District of California issued an order primarily approving the settlement and providing for notice of the settlement to stockholders of the Company in the matters captioned Hanna v. Kabot, et al., Case No. 5:23-cv-00374 (N.D. Cal.); Rivlen v. Kabot, et al., Case No. 2:23-cv-03120 (C.D. Cal.); Lindsey v. Quiroga, et al., Case No. 20230674 (Del. Ch.); and the litigation demand made by Momentus stockholder, Kamal Qureshi (collectively, the “Derivative Matters”). The proposed settlement calls for the Company to adopt certain corporate governance reforms and pay lead plaintiffs’ attorney’s fees, litigation expenses, and lead plaintiff service awards.

On September 15, 2024, the Company entered into a Securities Purchase Agreement with an investor, pursuant to which the Company issued and sold to an investor in a private placement transaction (the “September Offering”), (i) pre-funded warrants to purchase 5,000,000 shares of the Company’s Class A common stock at a purchase price of $0.55 per share (the “September Pre-Funded Warrants”), (ii) Class A warrants to purchase 10,000,000 shares of Class A common stock (the “Class A Warrants”), and (iii) Class B warrants to purchase 5,000,000 shares of Class A common stock (the “Class B Warrants” and, collectively with the Class A Warrants, the “September Warrants”).

The Company received aggregate gross proceeds of approximately $2.75 million, before deducting estimated placement agent commissions and expenses. The offering closed on September 17, 2024.

The September Pre-Funded Warrants have an exercise price of $0.00001 per share and are exercisable any time after issuance and will not expire until exercised.

The September Warrants have an exercise price per share of Class A common stock equal to $0.575 per share. The Class A Warrants will expire on March 17, 2030, and the Class B Warrants will expire on March 17, 2026. The exercise price and the number of shares of Class A common stock issuable upon exercise of the September Warrants is subject to appropriate adjustments in the event of certain stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events affecting the Class A common stock. The investor may not exercise the September Warrants until 6 months after the original issuance date of the September Warrants.

In connection with the September Offering, the Company entered into a Placement Agency Agreement on September 15, 2024, with the agency which assisted with the transaction. The Company paid a cash placement agent commission equal to 7.0% of gross proceeds from the September Offering and issued warrants (the “Placement Agent Warrants”) to purchase 500,000 shares of Class A common stock at an exercise price of $0.6325, exercisable immediately, as compensation for services. One half of the Placement Agent Warrants have a term of 18 months from the date of issuance and the other half have a term of five years from the date of issuance.