TD-1A
| Mission type | Astrophysics | 
|---|---|
| Operator | ESRO | 
| COSPAR ID | 1972-014A | 
| SATCAT no. | 05879 | 
| Spacecraft properties | |
| Launch mass | 473 kilograms (1,043 lb) | 
| Start of mission | |
| Launch date | 12 March 1972, 01:55:08 UTC | 
| Rocket | Delta N D88 | 
| Launch site | Vandenberg SLC-2E | 
| End of mission | |
| Decay date | 9 January 1980 | 
| Orbital parameters | |
| Reference system | Geocentric | 
| Regime | Low Earth | 
| Perigee altitude | 525 kilometres (326 mi) | 
| Apogee altitude | 544 kilometres (338 mi) | 
| Inclination | 97.5 degrees | 
| Period | 95.32 minutes | 
| Epoch | 11 May 1972, 19:00:00 UTC | 
TD-1A, or Thor-Delta 1A (or just TD-1), was a European astrophysical research satellite which was launched in 1972. Operated by the European Space Research Organisation, TD-1A made astronomical surveys primarily in the ultraviolet, but also using x-ray and gamma ray detectors.