Encyclopedia Astronautica
Mercury

Project 7969 Designs
Project 7969 designs. From left, top row: North American X-15B; Bell Dynasoar; Northrop Dynasoar; Republic Demi body; Avco manoeuvrable drag cone. Second row: Lockheed; Martin; Aeronutronics; Goodyear; McDonnell; Convair
Credit: © Mark Wade

• Mariner 10 American Mercury probe. One launch, 1973.11.03. More...

• Mariner 10 - . Payload: Mariner 73J. Mass: 526 kg (1,159 lb). Nation: USA. Agency: NASA; JPL. Program: Mariner. Class: Mercury. Type: Mercury probe. Spacecraft: Mariner 10. USAF Sat Cat: 6919 . COSPAR: 1973-085A. Mariner 10 was the first spacecraft to reach Mercury. Mariner 10 was placed in a parking orbit for 25 minutes after launch, then accelerated to a trans-Venus escape trajectory. The television and ultraviolet experiments were trained on the comet Kohoutek while the spacecraft was en route to its destination. The vehicle's first planetary encounter was with Venus on February 5, 1974, at a distance of 4200 km. Mariner 10 took 4,000 photos of Venus, which revealed a nearly round planet enveloped in smooth cloud layers. The gravity of Venus bent the orbit of the spacecraft and sent it towards Mercury. It crossed the orbit of Mercury on March 29, 1974, at 20:46 GMT, at a distance of 704 km from the surface. Photographs taken during the pass revealed an intensely cratered, Moon-like surface and a faint atmosphere of mostly helium. After the first flyby, Mariner 10 entered solar orbit, which permitted two more rendezvous with Mercury. On September 21, 1974, the second Mercury rendezvous, at an altitude of about 47,000 km, provided another opportunity to photograph the sunlit side of the planet and the south polar region. The third and final Mercury encounter on March 16, 1975, at an altitude of 327 km, yielded 300 photographs and magnetic field measurements. The vehicle was turned off March 24, 1975 when the supply of attitude-control gas was depleted.

• Messenger - . Payload: Discovery 8. Mass: 1,066 kg (2,350 lb). Nation: USA. Agency: NASA. Manufacturer: APL. Program: Discovery. Class: Mercury. Type: Mercury probe. Spacecraft: Messenger. USAF Sat Cat: 28391 . COSPAR: 2004-030A. The NASA Messenger probe to Mercury was was first placed into a parking orbit. The Delta booster second stage's second burn raised the orbit, then the PAM-D solid motor burned to put the probe on an escape trajectory into a 0.92 x 1.08 AU x 6.4 deg heliocentric orbit. Messenger (Mercury Surface, Space Environment, Geochemistry and Ranging) was to make an Earth flyby on August 1, 2005; Venus flybys in 2006 and 2007; and Mercury encounters in January and October 2008 , September 2009 and March 2011 . On this last encounter the Aerojet 660N engine was to fire to put Messenger into a 200 x 15,193 km x 80 deg orbit around Mercury. Launch delayed from March 10, May 11, August 2