Next month the NASA MSL Curiosity rover will attempt to land on Mars, marking the 49th mission to explore our near neighbor. Unlike other missions that used airbag landing systems, Curiosity will use a risky rocket powered sky crane because of its weight. Once landed the rover will look for signs of life.
Ever since Percival Lowell claimed to have seen canals and oases, going so far as to postulate an advanced civilization fighting to survive against all odds, we’ve been fascinated by Mars and the speculation that it might contain life. Famously, H. G. Wells was inspired by Lowell’s ideas and wrote “The War Of The Worlds” based on them.
Though thoroughly discredited now, the idea that Mars may contain life in some form still has the capacity to intrigue and inspire us. Over sixty years after Wells, Robert Heinlein wrote “Stranger in a Strange Land” about a human being raised by Martians, even though it was well known by that time that no large scale life existed on the planet.
Actual exploration of Mars over the past five decades has increased our knowledge of the “Red Planet” from the early Soviet flyby probes, through the U.S. Mariner, Viking and Pathfinder programs up to more recent missions such as the failed Beagle 2 lander.
So how likely is it that the mission will succeed? The answer to that is unfortunately “not very” – historically the success rate of Mars missions is not high. In fact, in 1997 Donald Neff, of Time Magazine, coined the idea of a “Galactic Ghoul” that survives by eating Mars probes.
Looking at the overall figures for all missions, out of a total of forty-nine (49) only twenty (20) have been a success. This gives Curiosity a base chance of just over forty percent (40%).
That figure, however, is for all mission types: Flyby, Orbiter, Lander, Rover and Sample Returns. When we look at the figures for Landers only the picture is much worse. Out of ten (10) attempts, only three (3) have succeeded: thirty percent (30%). Rovers have better odds: five (5) attempts and three (3) successes, giving a success rate of sixty percent (60%). The problem with a Rover is that it has to land before it can “rove”.
Combining these statistics we end with a figure of forty-five percent (45%). So going by past performance, Curiosity has just less than a one-in-two chance of success (this is just the chance of it landing and operating successfully, not the chance that it will discover signs of life).
Those aren’t great odds. Certainly technology has improved since the early attempts, but nevertheless there’s a high risk of failure. Does this mean we shouldn’t attempt such missions? Of course not. Fifty attempts is not a lot in an absolute sense and each time we learn more, making subsequent missions ones more assured. Not only that, we need to remember that science is experimental and therefore risky. Can you imagine what the world would be like if the early airplane builders had given up after fifty attempts?
Curiosity will tell us more about Mars, whether it finds signs of life or not. This will help make future missions a success and hopefully take us further down the path towards the day when humans step on the Martian surface.
I’ll be watching!