Geography provides an Opportunity to study other worlds

Mars_Viking_11h016 — Surface of Mars taken by Viking 1

By Paulette Cully

Until now, the record for the longest surviving mission of a lander on Mars was held by the Viking 1 Lander, the first spacecraft to touch down on the planet. The Lander successfully performed its mission, which was to take soil samples and search for life, over a period of 6 years and 116 days until in 1982 a faulty command sent by ground control resulted in loss of contact. But this month, the record has been bettered by a NASA robot buggy called Opportunity which landed on Mars in 2004. Opportunity’s twin rover Spirit, on the other side of Mars has not been heard from since March 22nd after becoming trapped in sand. Scheduled to last only three months, Opportunity is showing no signs of stopping and at the moment is slowly travelling from a crater called Victoria to another crater called Endeavour, eight kilometres away. The scientific objective of the mission is to search for and characterise rocks and soils that hold clues to past water activity on Mars. This information in turn will be used to help identify observed landforms such as gullies, channels and gorges.

Interestingly, according to Goro Komatsu writing in “Geography Compass”, on other planetary bodies, a wide range of fluids can be involved in creating landforms. For instance on the Moon, Venus, Mars, Io, and Titan, fluids including water, lava of varying compositions, carbon dioxide, and hydrocarbons, have been proposed for the origins of channels and valleys. On Earth, water either as a liquid or ice, is the most common fluid which produces landforms, although lava flows can also create surface features. Additionally, on Earth it is generally clear which fluid is responsible for surface features, because the formation process is in the main observable. On other planetary bodies however, planetary geologists and geomorphologists have to rely on their knowledge of geomorphology and the environment to infer which liquids were involved in the process of formation.