The United States sent two probes to Mars, Viking 1 and Viking 2. Scientists believed dark spots on the planet might be simple forms of life. The Viking probes were sent to collect samples and conduct experiments to see whether life really did exist on Mars.

The Viking probes had to main parts: an orbiter and a lander. The orbiter had two TV cameras. The lander was a  three-legged spacecraft that fit inside a shell for protection and carried all the scientific instruments.

Viking 1 was launched on August 20, 1975 and Viking 2 was launched on September 9, 1975.

The spacecraft made several orbits around Mars to look for a safe landing spot. Mars is covered with rocks, and if the lander landed on one of them, it could tip over.  This would make the lander useless. The original landing site was too rough, but on July 20, 1976, the lander touched down on the Golden Plains, a flat area on Mars. Within minutes of the landing it started to take pictures and sent them back to Earth. Viking 2 landed about 3,100 miles farther north on August 8, 1976.

Each lander had a robotic arm that had a scoop at the end.  These were used to pick up dirt samples and put them into a mini-chemistry lab for tests.  The landers also had a small weather station and an antenna for communication with Earth.

The Viking probes found no evidence of life, but it could not prove that life never existed on Mars.

The weather stations on the landers did find that Mars is much colder than Earth.  Since Mars is farther from the Sun than the Earth and has a much thinner atmosphere, temperatures fell to -166 degrees Fahrenheit at night and could only rise to about 70 degrees Fahrenheit at the equator.

Viking 1 made an atlas of Mars with different information about the planet for scientists.

End of the Mission