Dawn (spacecraft)
Dawn is a retired space probe that was launched by NASA in September 2007 with the mission of studying two of the three known protoplanets of the asteroid belt: Vesta and Ceres. In the fulfillment of that mission—the ninth in NASA's Discovery Program—Dawn entered orbit around Vesta on July 16, 2011, and completed a 14-month survey mission before leaving for Ceres in late 2012. It entered orbit around Ceres on March 6, 2015. In 2017, NASA announced that the planned nine-year mission would be extended until the probe's hydrazine fuel supply was depleted. On November 1, 2018, NASA announced that Dawn had depleted its hydrazine, and the mission was ended. The derelict probe remains in a stable orbit around Ceres.
Illustration of the Dawn spacecraft | |||||||||
| Mission type | Multi-target orbiter | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Operator | NASA / JPL | ||||||||
| COSPAR ID | 2007-043A | ||||||||
| SATCAT no. | 32249 | ||||||||
| Website | http://dawn.jpl.nasa.gov/ | ||||||||
| Mission duration | 11 years, 1 month and 4 days | ||||||||
| Spacecraft properties | |||||||||
| Manufacturer |
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| Launch mass | 1,217.7 kg (2,684.6 lb) | ||||||||
| Dry mass | 747.1 kg (1,647.1 lb) | ||||||||
| Dimensions | 1.64 × 19.7 × 1.77 m (5.4 × 65 × 5.8 ft) | ||||||||
| Power | 10 kW at 1 AU 1.3 kW at 3 AU | ||||||||
| Start of mission | |||||||||
| Launch date | September 27, 2007, 11:34 UTC | ||||||||
| Rocket | Delta II 7925H | ||||||||
| Launch site | Cape Canaveral SLC-17B | ||||||||
| Contractor | United Launch Alliance | ||||||||
| End of mission | |||||||||
| Disposal | Uncontrolled stable orbit | ||||||||
| Last contact | October 30, 2018 | ||||||||
| Orbital parameters | |||||||||
| Reference system | Ceres | ||||||||
| Regime | Highly elliptical | ||||||||
| Semi-major axis | 2,475.1356 kilometres (1,537.9780 mi) | ||||||||
| Eccentricity | 0.7952 | ||||||||
| Periapsis altitude | 37.004 kilometres (22.993 mi) | ||||||||
| Apoapsis altitude | 3,973.866 kilometres (2,469.246 mi) | ||||||||
| Inclination | 76.1042 degrees | ||||||||
| Period | 1,628.68 minutes | ||||||||
| RAAN | −79.4891 degrees | ||||||||
| Argument of periapsis | 164.1014 degrees | ||||||||
| Epoch | October 30, 2018, 00:00:00 UTC | ||||||||
| Flyby of Mars | |||||||||
| Closest approach | February 18, 2009, 00:27:58 UTC | ||||||||
| Distance | 542 km (337 mi) | ||||||||
| 4 Vesta orbiter | |||||||||
| Orbital insertion | July 16, 2011, 04:47 UTC | ||||||||
| Orbital departure | September 5, 2012, 06:26 UTC | ||||||||
| 1 Ceres orbiter | |||||||||
| Orbital insertion | March 6, 2015, 12:29 UTC | ||||||||
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Dawn mission patch | |||||||||
Dawn is the first spacecraft to have orbited two extraterrestrial bodies, the first spacecraft to have visited either Vesta or Ceres, and the first to have orbited a dwarf planet.
The Dawn mission was managed by NASA's Jet Propulsion Laboratory, with spacecraft components contributed by European partners from Italy, Germany, France, and the Netherlands. It was the first NASA exploratory mission to use ion propulsion, which enabled it to enter and leave the orbit of two celestial bodies. Previous multi-target missions using rockets powered by chemical engine, such as the Voyager program, were restricted to flybys.