Today in the history of astronomy, Mariner 10 has its second encounter with Mercury.
Mariner 10 made three flybys of Mercury, which is shown here in an enhanced-color image from NASA’s Messenger probe nearly four decades later. Credit: NASA / JHU Applied Physics Lab / Carnegie Inst. Washington
- Mariner 10, launched November 3, 1973, performed its second Mercury flyby on September 21, 1974, at an approximate distance of 48,000 kilometers.
- Mariner 10 was the first spacecraft to visit Mercury and the first mission designed for a dual-planet encounter, also including Venus.
- The mission’s objectives included investigating Mercury’s physical properties, atmospheric conditions, and capturing photographic and scientific data.
- Across its three Mercury flybys, Mariner 10 acquired over 2,700 images, resulting in the mapping of approximately half of Mercury’s surface, with the second flyby concentrating on the south polar region.
On Sept. 21, 1974, the Mariner 10 spacecraft made its second flyby of Mercury, passing by the surface at a distance of just under 30,000 miles (48,000 kilometers). Launched Nov. 3, 1973, Mariner 10 was the first spacecraft sent to Mercury, as well as the first mission designed to visit two planets. (It also visited Venus.) The probe’s goals at Mercury included studying the planet’s physical characteristics and atmosphere, and collecting photos and data. Across its three flybys, Mariner 10 took over 2,700 photos, ultimately mapping nearly half of Mercury’s surface. The second pass in September of 1974 was specifically focused on the south pole.