Last June, an enormous storm swept across the planet, clogging the atmosphere with sunlight-blocking dust, and the rover, unable to charge its batteries in the darkness, slipped into a deep sleep.
“I haven’t given up yet,” Squyres said.
But the end seems closer now than before. The team has attempted to contact Opportunity more than 600 times since it stopped communicating with Earth last June. At NASA, engineers operate in a realm with the motto “Failure is not an option,” and the agency has a long record of successfully repairing and reviving missions, from Apollo capsules to robotic probes. But the silence feels heavier with each passing day.
Dust storms are common during Martian summer, and Opportunity, about the size of a golf cart, had weathered a similar tempest about a decade earlier.
This time, as the Martian sky darkened, the rover automatically shut off nearly all functions to preserve energy. Engineers suspected that when the storm passed, Opportunity would recharge and awaken with a chirp sent back to Earth. But the skies cleared in September, and the rover didn’t wake up.
The team was not deterred. A season known for dust devils would soon begin on Mars. Perhaps Opportunity’s solar panels were coated in a thick layer of dust, and the wind gusts would wipe it away. But that season ends soon, and Opportunity remains silent.
Last week, NASA’s Jet Propulsion Laboratory, which operates Opportunity, announced that engineers would send a new set of commands to the rover in the next several weeks. The instructions assume some worst-case scenarios for the rover’s systems. “We have not exhausted all the possibilities yet, but we’ve exhausted quite a few of them,” Squyres said.
I asked Squyres whether the team had any more ideas for how to command the rover awake, in case their latest strategy doesn’t work. “No,” he said.
After that, the final call regarding Opportunity’s fate is up to NASA leadership. If the news is bad, the Opportunity team will join a grim club in space exploration: engineers and scientists who have said goodbye to spacecraft after years, sometimes decades, of effort and devotion. Some have known when the end would come, even deliberately planned for it. Others had no warning. In either case, letting go is painful.
The attempts to communicate, the wait, the uncertainty—these can be excruciating when the loss is unexpected, as Jim Spann, a chief scientist at NASA’s Marshall Space Flight Center, knows. In 2005, Spann was working on a spacecraft called IMAGE, or Imager for Magnetopause-to-Aurora Global Exploration, when it suddenly stopped talking to Earth.
Its stewards, stunned, scrambled to troubleshoot. String after string of commands went unanswered. After a year of silence from IMAGE, NASA concluded that it had been knocked out by the cosmic radiation that permeates space. Its hardware had suffered a particularly direct and unlucky hit.