Mercury Messenger
Artist's rendering of MESSENGER orbiting Mercury.
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| Mission type | Mercury probe |
|---|---|
| Operator | NASA |
| COSPAR ID | 2004-030A |
| SATCAT no. | 28391 |
| Website | messenger |
| Mission duration | Total: 10 years, 8 months and 28 days At Mercury: 4 years, 1 month and 14 days En route: 7 years Primary mission: 1 year First extension: 1 year Second extension: 2 years |
| Spacecraft properties | |
| Manufacturer | Applied Physics Laboratory |
| Launch mass | 1,107.9 kg (2,443 lb) |
| Power | 450 watts |
| Start of mission | |
| Launch date | August 3, 2004, 06:15:56 UTC |
| Rocket | Delta II 7925H-9.5 |
| Launch site | Cape Canaveral SLC-17B |
| Entered service | April 4, 2011 |
| End of mission | |
| Disposal | Deorbited |
| Destroyed | April 30, 2015 |
| Orbital parameters | |
| Reference system | Hermiocentric |
| Perihermion | 200 kilometres (120 mi) |
| Apohermion | 10,300 kilometres (6,400 mi) |
| Inclination | 80 degrees |
| Period | 12 hours |
| Epoch | Jan 1, 2000 |
| Flyby of Earth (gravity assist) | |
| Closest approach | August 2, 2005 |
| Distance | 2,347 kilometers (1,458 mi) |
| Flyby of Venus (gravity assist) | |
| Closest approach | October 24, 2006 |
| Distance | 2,990 kilometers (1,860 mi) |
| Flyby of Venus (gravity assist) | |
| Closest approach | June 5, 2007 |
| Distance | 337 kilometers (209 mi) |
| Flyby of Mercury | |
| Closest approach | January 14, 2008 |
| Distance | 200 kilometers (120 mi) |
| Flyby of Mercury | |
| Closest approach | October 6, 2008 |
| Distance | 200 kilometers (120 mi) |
| Flyby of Mercury | |
| Closest approach | September 29, 2009 |
| Distance | 228 kilometers (142 mi) |
| Mercury orbiter | |
| Orbital insertion | March 18, 2011, 01:00 UTC |
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MESSENGER (whose backronym is Mercury Surface, Space Environment, Geochemistry, and Ranging, and which is a reference to the Roman mythological messenger, Mercury) was a NASA robotic spacecraft that orbited the planet Mercury between 2011 and 2015. The spacecraft was launched aboard a Delta II rocket in August 2004 to study Mercury's chemical composition, geology, and magnetic field.
The instruments carried by MESSENGER were used on a complex series of flybys – the spacecraft flew by Earth once, Venus twice, and Mercury itself three times, allowing it to decelerate relative to Mercury using minimal fuel. During its first flyby of Mercury in January 2008, MESSENGER became the second mission after Mariner 10's 1975 flyby to reach Mercury.
MESSENGER entered orbit around Mercury on March 18, 2011, becoming the first spacecraft to do so. It successfully completed its primary mission in 2012. Following two mission extensions, the MESSENGER spacecraft used the last of its maneuvering propellant and deorbited as planned, impacting the surface of Mercury on April 30, 2015.
MESSENGER's formal data collection mission began on April 4, 2011. The primary mission was completed on March 17, 2012, having collected close to 100,000 images.MESSENGER achieved 100% mapping of Mercury on March 6, 2013, and completed its first year-long extended mission on March 17, 2013.MESSENGER's second extended mission lasted for over two years, but as its low orbit degraded, it required reboosts to avoid impact. It conducted its final reboost burns on October 24, 2014, and January 21, 2015, before crashing into Mercury on April 30, 2015.
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