Viking 1

Spacecraft· NASAinactive

Viking 1 — the first U.S. spacecraft to land on Mars (Chryse Planitia, 1976) and operate on the surface, for over six years.

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Key facts

Distance from Sun

1.5 AU

Status

Completed

Launched

1975

Mission & specifications

Mission

Operator: NASA
Launched: August 20, 1975
Status: Completed

Trajectory

Distance from the Sun: 1.5 AU
Distance from Earth: 1.9 AU
Distance from Mars: 2,499,968 km

Mission

Viking 1 was the first spacecraft to land successfully on Mars and complete its mission — a landmark in the search for life beyond Earth. Launched on 20 August 1975, it comprised an orbiter and a lander. The orbiter reached Mars in June 1976 and surveyed the planet to help pick a safe landing site; on 20 July 1976 — seven years to the day after Apollo 11 — the lander touched down on the rust-coloured plains of Chryse Planitia. It returned the first images ever taken from the Martian surface and operated for more than six years, far beyond its planned 90 days. Viking 1 carried a miniature biology laboratory to test the soil for microbial life. Its experiments produced puzzling, ambiguous results: one test looked positive, yet no organic molecules were found, and most scientists concluded the signals came from unusual soil chemistry rather than biology — a debate that still echoes. The lander also tracked weather and soil composition while the orbiter mapped almost the whole planet and found evidence of ancient catastrophic floods. Viking 1 set the template for every Mars lander that followed.

1975Launch toward MarsLaunch
A Titan IIIE-Centaur sends the Viking 1 orbiter and lander on an 11-month cruise.
1976Mars orbit insertionArrival
The orbiter arrives and scouts the surface to choose a safe landing site.
1976Landing in Chryse PlanitiaLanding
First successful Mars landing; returns the first images ever taken from the surface.
1976Biology experimentsMilestone
Three life-detection experiments return ambiguous results; no organic molecules are found.
1982Last transmissionMission end
After more than six years — far beyond its 90-day plan — the lander falls silent.

Images

The Viking spacecraft — orbiter and lander (Viking 1) — NASA (public domain) · Wikimedia Commons

The first photograph from the surface of Mars (Viking 1) — NASA/JPL (public domain) · Wikimedia Commons

Viking 1 landing site region in Chryse Planitia (marked on orbital mosaic) — NASA/JPL/Arizona State University · NASA Image Library

North Polar Ice Cap — NASA/JPL/USGS · NASA Image Library

Lunae Planum — NASA/JPL/Arizona State University · NASA Image Library

Mars on approach, Viking 1 — NASA/KSC · NASA Image Library

The United States Flag Stands On The Surface Of Mars — NASA/JPL · NASA Image Library

Example of Weathering And Sun Angle — NASA/JPL · NASA Image Library

Images from open archives · credit shown per image