Remembering a robot
Opportunity, a rover on Mars whose time there exceeded all expectations, was declared lost on February 12th
It travelled more than 500m kilometres simply as a passenger, sleeping dreamless, vacuum-packed. The five-and-a-half-month voyage was devoid of all interest until the very end, when the spacecraft lost 20,000kph of its velocity in just over six minutes as it plunged through an alien sky to the desert below. Parachutes spread and airbags deployed. The package bounced, rolled and came to rest.
Opportunity still had 45km to go.
Four hours after landing on January 25th 2004, it opened its eyes. Its makers, back on Earth, looked through them at a landing site as perfect as they could have wished for. Opportunity’s landing on Meridiani Planum, a little south of the Martian equator, had not been a particularly precise affair—it could have come down anywhere in an ellipse some 100km long and 18km wide. But by chance the spot where it had ended up, about 25km from the centre of the target, was inside a small crater dug out by a meteorite impact. On the side of that crater the scientists saw straight away the distinctive strata of sedimentary rock. Nothing of the sort had ever before been seen beyond the Earth. It was exactly the type of thing the robot had been sent to find.
Opportunity was officially MER-B, the second of the two rovers of the Mars Exploration Rover programme; MER-A, Spirit, had landed a few weeks earlier in the great Gusev Crater, almost half the planet away. Unofficially, it was Oppy, and often a she. The two rovers’ missions were due to last 90 sols—a sol being the 24 hours and 40 minutes it takes Mars to turn on its axis. Faced with that time limit, Opportunity’s minders were thrilled not to have to spend any of those precious sols just looking for interesting rocks.