TRACE
| Names | Explorer-73 SMEX-4 TRACE |
|---|---|
| Mission type | Heliophysics |
| Operator | NASA / GSFC |
| COSPAR ID | 1998-020A |
| SATCAT no. | 25280 |
| Website | TRACE |
| Mission duration | 1 year (planned) 12 years, 2 months and 19 days (achieved) |
| Spacecraft properties | |
| Spacecraft | Explorer LXXIII |
| Spacecraft type | Transition Region and Coronal Explorer |
| Bus | TRACE |
| Manufacturer | Goddard Space Flight Center |
| Launch mass | 250 kg (550 lb) |
| Dimensions | 1.9 × 1.1 m (6 ft 3 in × 3 ft 7 in) |
| Power | 220 watts |
| Start of mission | |
| Launch date | 2 April 1998, 02:42:39 UTC |
| Rocket | Pegasus XL (F21) |
| Launch site | Vandenberg, Stargazer |
| Contractor | Orbital Sciences Corporation |
| Entered service | 20 April 1998 |
| End of mission | |
| Deactivated | 21 June 2010, 23:56 UTC |
| Last contact | 21 June 2010 |
| Orbital parameters | |
| Reference system | Geocentric orbit |
| Regime | Sun-synchronous orbit |
| Perigee altitude | 520.0 km (323.1 mi) |
| Apogee altitude | 547.2 km (340.0 mi) |
| Inclination | 97.84° |
| Period | 95.48 minutes |
| Instruments | |
| TRACE Imaging Telescope | |
TRACE mission patch | |
Transition Region and Coronal Explorer (TRACE, or Explorer 73, SMEX-4) was a NASA heliophysics and solar observatory designed to investigate the connections between fine-scale magnetic fields and the associated plasma structures on the Sun by providing high-resolution images and observation of the solar photosphere, the transition region, and the solar corona. A main focus of the TRACE instrument is the fine structure of coronal loops low in the solar atmosphere. TRACE is the third spacecraft in the Small Explorer program, launched on 2 April 1998, and obtained its last science image on 21 June 2010, at 23:56 UTC.