Viking 2
American Mars lander that operated for 1,316 days and searched for life.
Viking 2 was a NASA mission that sent an orbiter and lander to Mars as part of the American Viking program. It was essentially identical to the Viking 1 mission and operated on the Martian surface for 1,316 days, making it one of the longest-lived landers of its era. The mission contributed to the search for life and the study of Martian soil and geology.
- launch_date
- September 9, 1975
- landing_date
- September 3, 1976
- mission_end
- April 12, 1980 (lander); July 25, 1978 (orbiter)
- field
- Planetary science
- nationality
- American
- known_for
- First successful Mars lander to operate for over three years; controversial life-detection experiments
Lore & Background
The Viking 2 craft was launched on September 9, 1975, using a Titan/Centaur launch vehicle. After a 333-day cruise to Mars, the orbiter began returning global images before entering orbit on August 7, 1976. The lander separated from the orbiter on September 3, 1976, and touched down at Utopia Planitia, about 200 km west of the crater Mie. Due to a radar misidentification, the thrusters fired an extra time 0.4 seconds before landing, cracking the surface and raising dust. The lander settled with one leg on a rock, tilted at 8.2 degrees.
The orbiter's primary mission ended on October 5, 1976, at the beginning of solar conjunction. It continued in an extended mission, making close approaches to Deimos in October 1977. The orbiter developed a leak in its propulsion system and was turned off on July 25, 1978, after returning almost 16,000 images in about 706 orbits. The lander, powered by radioisotope generators, operated until its batteries failed on April 12, 1980. In July 2001, the lander was renamed the Gerald Soffen Memorial Station.
Reader's Guide
Viking 2's significance lies in its dual role as both an orbiter and lander, providing extensive imaging and surface data. The orbiter returned nearly 16,000 images and made discoveries about water on Mars, including evidence of ancient river valleys and branched stream areas suggesting past rainfall. The lander's biology experiments produced conflicting results: the Gas Chromatograph/Mass Spectrometer and Gas Exchange experiment gave negative results for life, while the Pyrolytic Release and Labeled Release experiments gave positive results. This controversy has persisted, with some scientists still believing the results indicated living reactions. The mission also analyzed soil, finding abundant silicon and iron, along with sulfur, chlorine, and magnetic materials. The discovery of perchlorate on Mars by later missions has complicated the interpretation of Viking's organic chemistry results. Viking 2's legacy includes its role in shaping the debate about life on Mars and its contributions to understanding Martian geology and water history.
Did You Know?
- The Viking 2 lander operated on the surface for 1,316 days, or 1,281 sols.
- The orbiter returned almost 16,000 images in about 706 orbits around Mars.
- The lander touched down with one leg on a rock, tilted at 8.2 degrees.
- In July 2001, the Viking 2 lander was renamed the Gerald Soffen Memorial Station.
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