| Document and Entity Information | Jun. 15, 2023 |
| Document And Entity Information [Line Items] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001846750 |
| Document Type | 8-K |
| Document Period End Date | Jun. 15, 2023 |
| Entity Registrant Name | Trajectory Alpha Acquisition Corp. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-41143 |
| Entity Tax Identification Number | 86-1837862 |
| Entity Address, Address Line One | 99 Wall Street |
| Entity Address, Address Line Two | Suite 5801 |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10005 |
| City Area Code | (646) |
| Local Phone Number | 450-2536 |
| Written Communications | true |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Units Each Consisting Of One Share Of Class A Common Stock And One Half Of One Redeemable Public Warrant [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Units, each consisting of one share of Class A Common Stock and one-half of one redeemable Public Warrant |
| Trading Symbol | TCOA.U |
| Security Exchange Name | NYSE |
| Common Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Class A Common Stock, $0.0001 par value per share |
| Trading Symbol | TCOA |
| Security Exchange Name | NYSE |
| Public Warrants Each Exercisable For One Share Of Class A Common Stock At An Exercise Price Of 11.50 Per Share [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Public Warrants, each exercisable for one share of Class A Common Stock at an exercise price of $11.50 per share |
| Trading Symbol | TCOA WS |
| Security Exchange Name | NYSE |
