Choosing a Landing Site for MSL
Scientists and mission planners for NASA's Mars Science Laboratory (MSL) are looking for a site that combines scientific attractiveness with engineering feasibility. The MSL rover has a landing target-circle 20 kilometers (12 miles) in diameter. (This is also the rover's minimum driving distance.)
Two criteria are important in selecting a landing site: safety and scientific interest. To be safe for MSL to land, a site must first be flat and not too windy.
Once the rover lands, it's important that the terrain is suitable for driving. A site covered with lots of rocks may have boulders big enough to impede the rover's driving ability - a rock half a meter (20 inches) high is the biggest the rover can straddle. Also, as we've learned from the MER Spirit and Opportunity rovers, areas with a lot of sand or dust can snare a rover's wheels.
These images of potential MSL landing sites will be used not only to assess the safety of the sites, but also to determine their scientific value, and what we might learn about Mars by going to them.
Each image centers on a candidate landing site and covers an area 3° x 3°, or about 180 kilometers (approximately 110 miles) square. Here's what each kind of image shows.
Day IR: This is a mosaic of THEMIS images taken at infrared wavelengths during afternoon - it shows ground temperatures, with warmer areas appearing brighter. Day IR images show the basic landscape at each site, with each pixel being 100 meters (330 feet) in size.
Night IR: A mosaic of THEMIS images taken at infrared wavelengths shortly before dawn, this shows the ground temperature, with warmer areas appearing brighter. Each pixel is 100 meters (330 feet) in size.
VIS: A mosaic of THEMIS images taken at visible wavelengths during daytime, this shows the surface about as your eyes would see it. VIS coverage of MSL sites is still spotty, but THEMIS mission planners are currently targeting these sites to improve coverage. Each pixel is 18 meters (59 feet) in size.
Thermal Inertia: Thermal inertia is a measure of how fast the ground surface heats up and cools down. Brighter areas have a higher thermal inertia; during daytime, these are slower to warm and, after sunset, they are slower to cool. High thermal inertia areas tend to have more rocks and hardened materials at the surface, while low thermal inertia regions are dustier and sandier. Each pixel is 100 meters (330 feet) in size.
Night IR on Day IR: This false-color mosaic combines both IR views and has been colorized to show warmer areas in redder tints and colder areas in bluer tints. These images help scientists match surface properties (such as rocky or sandy regions) with the landscape. Each pixel is 100 meters (330 feet) in size.
Thermal Inertia on Day IR: Similar to the Night IR on Day IR, this false-color mosaic shows color-coded thermal inertia values. Rockier areas appear redder. Each pixel is 100 meters (330 feet) in size.
Decorrelation Stretched Day IR Images: Different portions of the infrared spectra are combined to produce the variation in color seen in these images. Different colors represent different rock compositions on the surface.