Since the 1990s humans have been engaged on a concerted effort to understand Mars. The landing of Mars Curiosity on the surface in the early hours of August 6, 2012, is the latest effort to learn about one of our closest neighbors in the solar system. And its success is something to be cheered.
NASA has been pursuing a strategy for Mars exploration that may best be characterized with the motto, “Follow the Water.” In essence, this approach noted that life on Earth is built upon liquid water and that any life elsewhere would probably have chemistries built upon these same elements. Accordingly, to search for life on Mars, past or present, NASA’s strategy must be to follow the water. If scientists could find any liquid water on Mars, probably only deep beneath the surface, the potential for life to exist was also present.
The Mars of today, without any evidence of water whatsoever on the surface, probably had water flowing freely in its ancient history. Evidence of changes to the planet’s surface from fast flowing water has been collected by many space probes orbiting the planet since the latter 1990s. The spacecraft to open this possibility was Mars Global Surveyor, reaching the planet in 1998 and a new and exciting era of scientific missions to study the red planet. Its discoveries tantalized us about the possibility of life on Mars, at least in the distant past, for there was evidence present that there might actually be water in the substrata of Mars.
But reaching Mars has always been difficult, and globally more missions have failed than have succeeded in accomplishing what they set out to do. Early on, there were spectacular failures, but even in the last fifteen years there have been several failures. Overall, out of 40 missions, only 16 have been successful and 24 have failed. This means that overall any individual Mars mission has a 1 in 3 chance of success. That is not a bad batting average in major league baseball, but for the limited number of chances we have for reaching Mars with individual missions we have to increase our success rate. Check out this chart:
With Mars Curiosity’s successful landing on August 6, this new mission represents a major step forward in a long process of Mars exploration. It is important to recognize just how difficult exploration of the red planet has been and continues to be. For one thing, the success of the entry, descent, and landing technology pioneered on this mission will permanently affect how NASA undertakes future Mars efforts. I was something of a skeptic about the Sky Crane Landing System used here, questioning its complexity, but I’m pleased to be proven wrong with this successful landing. We will be able to use this approach to touching down on the Martian surface for successively heavier and more capable payloads in the future.
In addition to the landing, a successful Curiosity mission brings to the planet’s surface a formidable life sciences laboratory that may well help us resolve beyond serious question whether or not life ever existed on the red planet. This rover is the first full-scale astrobiology mission to Mars since the Viking landers of 1976. Having followed the water, and found evidence of it, it is now time to answer this massively large question: Are there locations on or under the surface that could have supported—or might still support—life on Mars? This is a bold question requiring the boldest type of mission to answer it. Mars Curiosity has 10 different instruments designed to help find the answer to this question. It will look for processes that might have helped preserve clues about life, either now or in the past, on the red planet.
Here’s to the team that landed Curiosity on the surface of Mars in a very small target on Gale Crater! More than fifty years ago President John F. Kennedy called upon the American people to support expansive space exploration efforts, “not because they are easy, but because they are hard.” Nothing in robotic space exploration has proven harder than successfully landing on Mars and undertaking extended missions there. Mars Curiosity is advancing that challenge to learn about the cosmos, but it is only one step along a difficult path.
Additional missions will follow this one, at least as long the American public chooses to support the effort through our democratic process. And we should, or we should be ashamed of ourselves. All I can say at present after the superb Martian landing is drive on Curiosity, drive on!