Ulysses (spacecraft)
Ulysses (/juːˈlɪsiːz/ yoo-LISS-eez, UK also /ˈjuːlɪsiːz/ YOO-liss-eez) was a robotic space probe whose primary mission was to orbit the Sun and study it at all latitudes. It was launched in 1990 and made three "fast latitude scans" of the Sun in 1994/1995, 2000/2001, and 2007/2008. In addition, the probe studied several comets. Ulysses was a joint venture of the European Space Agency (ESA) and the United States' National Aeronautics and Space Administration (NASA), under leadership of ESA with participation from Canada's National Research Council. The last day for mission operations on Ulysses was 30 June 2009.
Ulysses spacecraft | |
| Names | Odysseus |
|---|---|
| Mission type | Heliophysics |
| Operator | NASA / ESA |
| COSPAR ID | 1990-090B |
| SATCAT no. | 20842 |
| Website | NASA Page ESA Page |
| Mission duration | 18 years, 8 months, 24 days |
| Spacecraft properties | |
| Manufacturer | Astrium GmbH, Friedrichshafen (formerly Dornier Systems) |
| Launch mass | 371 kg (818 lb) |
| Payload mass | 55 kg (121 lb) |
| Dimensions | 3.2 m × 3.3 m × 2.1 m (10.5 ft × 10.8 ft × 6.9 ft) |
| Power | 285 watts |
| Start of mission | |
| Launch date | 6 October 1990, 11:47:16 UTC |
| Rocket | Space Shuttle Discovery (STS-41) with Inertial Upper Stage and PAM-S |
| Launch site | Kennedy Space Center, LC-39B |
| Contractor | NASA |
| End of mission | |
| Disposal | Decommissioned |
| Deactivated | 30 June 2009 |
| Orbital parameters | |
| Reference system | Heliocentric orbit |
| Perihelion altitude | 1.35 AU |
| Aphelion altitude | 5.40 AU |
| Inclination | 79.11° |
| Period | 2,264.26 days (6.2 years) |
| Flyby of Jupiter (gravity assist) | |
| Closest approach | 8 February 1992 |
| Distance | 440,439 km (6.3 Jupiter radii) |
Ulysses mission patch | |
To study the Sun at all latitudes, the probe needed to change its orbital inclination and leave the plane of the Solar System. To change the orbital inclination of a spacecraft to about 80° requires a large change in heliocentric velocity, the energy to achieve which far exceeded the capabilities of any launch vehicle. To reach the desired orbit around the Sun, the mission's planners chose a gravity assist maneuver around Jupiter, but this Jupiter encounter meant that Ulysses could not be powered by solar cells. The probe was powered instead by a radioisotope thermoelectric generator (RTG).
The spacecraft was originally named Odysseus, because of its lengthy and indirect trajectory to study the solar poles. It was renamed Ulysses, the Latin translation of "Odysseus", at ESA's request in honor not only of Homer's mythological hero but also of Dante's character in the Inferno. Ulysses was originally scheduled for launch in May 1986 aboard the Space Shuttle Challenger on STS-61-F. Due to the 28 January 1986 loss of Challenger, the launch of Ulysses was delayed until 6 October 1990 aboard Discovery (mission STS-41).