Mars is not nice. It's not a fun, easy place to insert a satellite into orbit or to land a lander.
53% of missions to Mars have ended in failure, whether it be a failure to launch, a failure en route, or a failure to orbit and/or land.
This Wednesday, the ESA's Schiaparelli probe crash landed on Mars when its parachute released a minute too early. So this week I'd like to explore some of the more epic failures and why it's so hard for people to send robots, let alone people, to the red planet.
Let's first go through a brief timeline of failure (with a few success stories). I've color-coded things where orange is a 'sorta' success and green is a successful mission. You can see that from the 60s to the end of the 90s there were few successes...
And onward to the next century, where the outlook get a little greener.
Overall, the missions that didn't work often failed to launch, insert into orbit correctly, or land gently. Going to Mars is especially challenging due to a few special factors including the length of the mission (it takes a few years and a lot of fuel to even arrive at Mars) and the demands of a delay in light travel time to communicate with the probes. In other words, you cannot rely upon real-time corrections to fix glitches in the computers. Therefore, the orbiters often fail to arrive at Mars due to computer or software problems that occurred during the extra-long journey. These glitches either shut down communication or resulted in an altered trajectory that cannot be corrected.
Only four space agencies have successfully sent a mission to Mars (NASA=USA, Soviet and RSA=Russia, ISRO=India, and the ESA=European).
If missions make it to Mars, it is often difficult for orbiters to insert into the atmosphere and landers to navigate the challenging and dynamic atmosphere during their descent. Therefore, the landings are seldom soft because they require a multi-stage descent to slow the lander. Unlike on Earth, you cannot rely upon a thick atmosphere to slow your fall and must often do fancy things like a sky crane (Curiosity landed this way).
And then, even when the landers succeed, Mars' intense seasons, polar winters, dust storms, and winds can kill the rovers that have successfully landed on the surface. For instance, Spirit's solar panels eventually got buried by dust and the Phoenix lander froze to death in winter.
However, despite all the failures of the past, we're learning. We've learned to use metric units when building a spacecraft. We've learned how to launch long-range missions. We've learned how to use fancy technology to land on the surface of a planet with little atmosphere.
The real question is: How long before we're confident enough to send humans to the red planet? This will involve a whole series of new challenges and I can't help but wonder if we are able to face the daunting 53% failure rate to achieve this goal.