Viking 1 and Viking 2 Missions to Mars

Pictures of Mars - View from Lander 2
Copyright 1995-2003, California Institute of Technology. Pictures of Mars - View from Lander 2

Viking 1 and 2

The Viking missions were ambitious explorations designed to help planetary scientists learn more about the surface of the Red Planet. They were programmed to search for evidence of water and signs of life past and present. They were preceded by mapping missions such as the Mariners, and a variety of Soviet probes, as well as numerous observations using Earth-based observatories. 

Viking 1 and Viking 2 were launched within a couple of weeks of each other in 1975 and landed in 1976. Each spacecraft consisted of an orbiter and a lander which traveled attached together for nearly a year to reach Mars orbit. Upon arrival, the orbiters began taking pictures of the Martian surface, from which final landing sites were selected. Eventually, the landers separated from the orbiters and soft landed onto the surface, while the orbiters continued imaging. Eventually both orbiters imaged the entire planet at the highest resolution their cameras could deliver.

The orbiters also conducted atmospheric water vapor measurements and infrared thermal mapping and flew within 90 kilometers of the moon Phobos to take images of it. The images revealed further details of volcanic rocks on the surface, lava plains, huge canyons, and the effects of wind and water on the surface.

Back on Earth, teams of scientists worked to assimilate and analyze the data as it came in. Most were located at NASA's Jet Propulsion Laboratory, along with a collection of high-school and college students who served as interns for the project. The Viking data are stored at JPL, and continue to be consulted by scientists studying the surface and atmosphere of the Red Planet.

Science by the Viking Landers

The Viking landers took full 360-degree pictures, collected and analyzed samples of the Martian soil, and monitored surface temperatures, wind directions, and wind speeds every day.Analysis of the soils at the landing sites showed the Martian regolith (soil) to be rich in iron, but devoid of any signs of life (past or present). 

For most planetary scientists, the Viking landers were the first missions to truly tell what the Red Planet was really like from "ground level". The appearance of seasonal frost on the surface revealed that the Martian climate was similar to our seasonal changes here on Earth, although the temperatures on Mars are much cooler. Wind gauges revealed the near-constant movement of dust around the surface (something that other rovers such as Curiosity studied in more detail. 

The Vikings set the stage for further missions to Mars, including an array of mappers, landers, and rovers. These include the Mars Curiosity rover, the Mars Exploration Rovers, the Phoenix Lander, the Mars Reconnaissance Orbiter, the Mars Orbiter Mission, MAVEN mission to study the climate, and many others sent by the U.S., Europe, India, Russia, and Great Britain. 

Future missions to Mars will eventually include Mars astronauts, who will take the first steps on the Red Planet, and examine this world first-hand. Their work will continue the exploration begun by the Viking missions.

Viking 1 Key Dates

  • 08/20/75: Viking 1 Launch (21:22 UT)
  • 06/19/76: Viking 1 Arrival at Mars
  • 07/20/76: Viking 1 Mars Landing (11:53:56)
  • 08/07/80: Viking 1 End of Mission (Orbiter)
  • 02/01/83: Viking 1 End of Mission (Lander)
  • Status: Viking 1 Mission Complete

Viking 2 Key Dates

  • 09/09/75: Viking 2 Launch (18:39 UT)
  • 08/07/76: Viking 2 Arrival at Mars
  • 09/03/76: Viking 2 Mars Landing (22:37:50 UT)
  • 07/24/78: Viking 2 End of Mission (Orbiter)
  • 04/12/80: Viking 2 End of Mission (Lander)
  • Status: Viking 2 Mission Complete

The legacy of the Viking landers continues to play a role in our understanding of the red planet. Successive missions all extend the Viking missions' reach to other parts of the planet. The Vikings provided the first extensive data taken "on site", which provided a benchmark for all other landers to achieve.

Edited by Carolyn Collins Petersen