Viking 1 landing in Chryse Planitia

Viking 1 · 1976 CE – 1982 CE · Mars

Viking 1 landing in Chryse Planitia — Viking 1 · 1976 CE – 1982 CE · Mars — Recorded expedition route · schematic map

Land safely on Mars, photograph the surface and test the soil for life.

Historical context

NASA’s Viking project, which cost roughly a billion dollars, sent two orbiters and two landers to Mars to photograph the surface, analyse the soil and look for life. Viking 1 entered orbit on 19 June 1976, but its pictures showed the chosen site cut by channels and craters, and the landing set for 4 July slipped to 20 July. The lander then worked on the western slopes of Chryse Planitia for more than six years. Its biology experiments gave reactions that most of the team came to explain by soil chemistry, and that one experimenter, Gilbert Levin, read as signs of life.

The voyage, step by step

  1. Descent to Chryse

    20 July 1976

    On 20 July 1976 the lander separated from its orbiter and, about three hours later, entered the thin air behind a heat shield. It opened a sixteen-metre parachute some six kilometres up and fired its landing rockets for the last kilometre and a half, touching down at 11:53 Universal Time, as the event happened on Mars, and at 4:13 in the afternoon, local time at the site.

  2. The first picture from the ground

    20 July 1976

    Twenty-five seconds after touchdown, camera 2 began the first picture, looking down at a footpad on stony ground. The lander relayed it through the orbiter overhead, and its first lines appeared on screens at the Jet Propulsion Laboratory soon after 5:54 in the morning, Pacific Daylight Time.

  3. A pin in the arm

    1976 CE

    On 22 July the sampler arm stuck as it was pulled back after dropping the protective shroud over its scoop. Engineers traced the fault to a locking pin that had not fallen free and commanded a longer extension, and pictures taken on 25 July showed the pin lying on the ground.

  4. Three tests for life

    1976 CE

    From 28 July, soil went into three experiments that looked for signs of metabolism. In two of them, when it was moistened and fed nutrients, gas came off vigorously, and on 31 July Harold Klein, the biology team leader, said the labelled release result would, to a first approximation, look very much like a biological signal.

  5. Years of weather

    1979 CE

    From its first sols the lander logged pressure, temperature and wind. Over more than a Martian year its daily mean pressure fell and rose again, revealing a seasonal cycle as carbon dioxide froze onto a polar cap and returned to the air.

  6. Mutch Memorial Station

    11 November 1982

    The lander’s last transmissions reached Earth in November 1982, after six years and three months on the surface: on 11 November by Asif Siddiqi’s chronicle for NASA, on 13 November by NASA’s archive. A faulty command sent from Earth ended contact.

Outcome

More than six years of pictures, weather and soil chemistry; no organic molecules of Martian origin were reported, and the biology results were read by most of the team as chemistry and by Gilbert Levin as life.

Viking 1

Orbiter and lander that reached Mars in 1976; the lander, which NASA calls the first truly successful Mars landing, worked in Chryse Planitia from July 1976 to November 1982.

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