The hibernating Spirit rover hasn’t communicated with Earth since March 22 of this year, and while everyone hopes for the best, NASA, it seems, wants to brace rover fans for the worst, just in case. The space agency has dutifully issued a couple of press releases the past few months saying it is possible we may not hear from the rover again. Even Cornell University – home of MER PI Steve Squyres — featured an article in their Daily Sun newspaper this week with the headline, “Mars Rover May Have Lost Power for Good.” But yet, Squyres is quoted “Spirit hasn’t died; we haven’t heard from it, but we suspect it is still alive and we are waiting to hear from it.”
So what are Spirit’s chances? And what are the real sentiments of everyone on the rover team –has anyone actually forsaken hope of hearing from the plucky rover that surprised us time and time again? Universe Today checked in with Mars rover driver Scott Maxwell for an update:
“I don’t have the sense that anyone around here has given up on Spirit,” Maxwell said in an email. “The general consensus, I think, is that she’ll wait until a day or so past the last time anyone expects to hear from her, and then pop up with 800 Watt-hours per sol.”
That’s the Spirit rover, for you. Always full of surprises.
And a robotic version of Lazarus rising from the dead wouldn’t be all that astounding. In the past, she has amazed us all by doing things like being able to climb to the top of Husband Hill and shuffle back down again, then continuing to keep on truckin’ even when a wheel gave out – years ago, and lately, she still provided scientific discoveries even while asleep.
Even though it seems like ages since we’ve heard from the rover, remember that the Martian winter in Spirit’s location runs through November here on Earth, so it hasn’t even started to really warm up yet.
“There was a long, low-probability period starting about late July or early August when we didn’t expect to hear from her, but we theoretically could have,” Maxwell said. “That probably contributes to the idea that we “should” have heard from her by now — but really, there was just a low, flat, leading edge of the probability curve.”
Back in July, rover engineers began a “sweep and beep” campaign, where instead of just listening, they send commands to the rover to respond back with a communications beep. If the rover is awake and hears the call, she will send back a beep.
But we haven’t heard a beep yet.
The rover is likely in a low-power hibernation mode since it wasn’t able to get to a favorable slope to capture sunlight on its solar panels during its fourth Martian winter. The low angle of sunlight during these months limits the power able to be generated. During hibernation, the rover shuts down communications and other activities so available energy can be used to recharge and heat the batteries, and to keep the mission clock running.
Maxwell said their models say the solar power at Gusev Crater should just now be getting good enough that Spirit could have multiple wakeups per sol. “Theoretically we have a shot at getting our “beep” sequence in on any of those wakeups,” he said. “It’s still the case that any individual wakeup presents us only with a low-probability chance of hearing from her, we just potentially get more of those chances per unit of time.”
It is kind a crapshoot, however, Maxwell said, and it might still be weeks or even months before they get the winning pull of the slot machine handle.
Maxwell is optimistic, and although he didn’t give any percentages on how likely it is that Spirit will wake up, he said the situation is certainly not dire…yet.
“Having said all that, it would be awfully nice to actually get a beep from Spirit and know she’s there,” Maxwell said. “I miss her. I hope she calls home soon.”
Hang in there, Spirit. And you, too, Scott, and all your rover compatriots.