The clock is ticking and NASA's Curiosity rover with its burden of the Mars Science Laboratory is heading for a potentially historic landing on Mars. As we all wait to find out what happens, here's a small look at the landing site.
This is Gale Crater, a 150 km (about 90 mile) depression just south of the martian equator that was formed sometime around 3.5 billion years ago during a massive asteroid or comet impact. A number of things are particularly interesting about Gale, and have resulted in its selection as the aim point for Curiosity.
A key aspect of the terrain in Gale is the enormous raised interior 'mound' (if you can call a 4-5 km bump a mound rather than a mountain). It's special, and especially interesting, because it appears to be a highly layered structure - produced by the weathering of zone after zone of sedimentary material. In other words, it looks like Gale once contained a great lake, or was possibly within a larger sea.
Not only does this make Gale a great place to go look for signs of the chemistry and chemical alterations we associate with life, but it also makes it an easy place to do this. Layers of history are quite literally exposed to plain sight, just as they are in many places here on Earth.
Here's another shot of Gale, this time from above, together with the targeted landing site. The shape of the landing zone is a little misleading in this shot, it is in fact rather more of a ellipse due to the atmospheric entry vector. This perspective image below shows that a little clearer.
This is about 7 km wide by 20 km long, a significantly smaller target area than other recent Mars landings (e.g. Spirit/Opportunity, or Pathfinder) due to the powered descent. And where is Gale on the global map of Mars?
It's here, shown in relation to other Mars lander missions.