Life in the Universe

Life in Our Solar System

What was the primary mission of the Viking program?

In the 1970s, there was still uncertainty about the existence of life on the surface of Mars. Although the current conditions had been shown to be inhospitable to life as we know it on Earth, data from the Soviet Mars series and U.S. Mariner series of space probes suggested that the cold, dry periods of the Martian present may have alternated with warm, moist periods in the Martian past, with each cycle lasting perhaps fifty thousand years. This raised the possibility that life forms may have evolved on the surface of Mars that would lie dormant during the hostile climatic periods and then reactivate when the climate was more hospitable. Thus, the primary mission of the Viking probes was to examine Mars thoroughly for any signs of life, dormant or otherwise.


This is a web preview of the "The Handy Astronomy Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App