Their anxiety turned out to be prophetic. When the $110 million lander finally touched down on the planet, it did so with all the subtlety of Wile E. Coyote's anvil falling off the cliff. Investigators later posited that the most likely cause was a bogus "I've landed" signal sent to the computerized flight-control system when, in fact, the lander was still 131 feet up. It had deployed its legs as planned. But that triggered an errant signal that caused the landing rockets to shut down prematurely, leaving the craft to crash into Mars at about 50 miles per hour. Controllers were never able to make contact with the lander or the two probes it ferried.
The debacle marked a low point in NASA's decades-old quest to explore Mars. The loss of the lander was the third failure in six years. In the 13 years since, however, the effort has undergone a remarkable turnaround. The agency has overseen the most comprehensive, systematic – and successful – effort to investigate another planet since the dawn of the Space Age. A string of six triumphant orbiters, landers, and rovers has helped unlock mysteries about a planet that has captivated humans since the Babylonians.
Now, as the most sophisticated rover humans have ever sent into the cosmos inches its way along the planet's ruddy surface, mankind may be reaching a hinge moment in the study of Mars. Curiosity's slow journey across Gale Crater marks a shift from tracing the history of water on Mars to focusing on efforts that could help answer a question humans have been asking since Dutch astronomer Christiaan Huygens drew up the first practical sketches of the planet in the mid-1600s: Did Mars ever host life?
Curiosity's landing alone was euphoric for NASA: Its soft touchdown in August, at the end of a "sky crane" tether, heralded a new era of precision landings that was watched by millions around the world, creating a triumphant moment for an often-beleaguered space agency.