A Goldstone 111.5-foot (34-meter) beam-waveguide antenna, part of the Goldstone Deep Space Communications Complex in the Mojave Desert in California. Antennas like this are being used to try to communicate with the Opportunity rover. Photo Credit: NASA/JPL-Caltech
NASA’s Opportunity rover has now been on Mars for an incredible 15 years since its landing in Meridiani Planum in January 2004. But it is now looking increasingly likely that the mission has come to an end – the rover hasn’t been heard from since June 10, 2018, after a global dust storm knocked out communications.
The storm finally abated a few months ago, but still not a peep from Opportunity, meaning that it has probably – but not definitely yet – succumbed to having very little power to operate with.
The rover went into a hibernation mode, and mission engineers were hoping it would survive the dust storm wake up again and regain communications after it had some time to recover. That hasn’t happened yet.
But NASA still hasn’t given up yet. A few days ago, new commands were sent to Opportunity to try to compel it to communicate, if it can. These commands are specifically designed to address “low-likelihood events” that might be preventing the rover from transmitting, and they will continue for several weeks.
One of the last views seen by Opportunity before it went into hibernation mode last June, looking down into Endeavour crater. This image is part of a larger panorama. Photo Credit: NASA/JPL-Caltech/Cornell/Arizona State Univ.
“We have and will continue to use multiple techniques in our attempts to contact the rover,” said John Callas, project manager for Opportunity at JPL. “These new command strategies are in addition to the ‘sweep and beep’ commands we have been transmitting up to the rover since September.”
Previously, engineers were primarily just listening for a signal from Opportunity, but with “sweep and beep,” they will also send specific radio commands to the rover to try to get it to wake up.
By January 22, 2019, over 600 commands had been sent to the rover, to no avail.
“Over the past seven months we have attempted to contact Opportunity over 600 times,” said Callas. “While we have not heard back from the rover and the probability that we ever will is decreasing each day, we plan to continue to pursue every logical solution that could put us back in touch.”
There are three possible scenarios that the new strategy addresses – that the rover’s primary X-band radio which Opportunity uses to communicate with Earth has failed, that both the primary and secondary X-band radios have failed or that the internal clock, which provides a timeframe for its computer brain, is now offset.
The last transmitted image from Opportunity, when solar radiation was one fortieth its pre-storm level and solar panel power was only 22 watt-hours, down from the normal 300 watt-hours. Photo Credit: NASA/JPL-Caltech
Any of those scenarios are possible, or it may be that none of them have occurred and the rover really is dead. The team considers them to be unlikely, although still a possibility.
The region Opportunity is in is currently in “dust clearing season,” when winds increase and could clean off the solar panels of dust, which has occurred many times before. But that time is now starting to draw to a close. It had been hoped that perhaps a simple cleaning off of the solar panels would allow Opportunity to wake up again, but that also hasn’t;t happened.
Another problem is that winter is approaching in the region. Since the rover is underpowered, the extreme cold could fatally damage the batteries, wiring or computer systems. That would make it even more difficult, if not impossible, to regain contact.
So what happens if the rover team still doesn’t hear back from Opportunity? They will then need to consult the Mars Program Office at JPL and NASA Headquarters to figure out what the next steps should be, including whether to even continue attempts to contact the rover at all. As previously stated by NASA:
Series of images showing the gradually darkening skies at Opportunity’s location due to the dust storm. Image Credit: NASA/JPL-Caltech/TAMU
“After a review of the progress of the listening campaign, NASA will continue its current strategy for attempting to make contact with the Opportunity rover for the foreseeable future. Winds could increase in the next few months at Opportunity’s location on Mars, resulting in dust being blown off the rover’s solar panels. The agency will reassess the situation in the January 2019 time frame.”
Opportunity’s twin rover Spirit, which landed just after Opportunity, died in March 2010 after it got stuck in a sand dune and was unable to be freed.
If Opportunity really is gone, it will be a sad end to a fantastic mission. Opportunuty’s nominal mission was for 90 days when it first landed, but it lasted for 15 years – 61 times longer than its warranty.
“You can always look back and say, ‘This is a rover that way outlived her expectations and accomplished a lot.’ But that doesn’t make the grief go away,” said Mark Lemmon, an atmospheric scientist at the Space Science Institute. “It’s odd to think about grief being associated with a machine. But it’s a part of our lives. We worry about it; we think about its power, its usage of energy, like a care-and-feeding kind of thing. It’s not just a piece of machinery. It obviously is that, but also something that’s connected to everybody. We’ve gone through 15 years of living our lives, with operating the rover on Mars being the one constant thing in that.”
Some of the “blueberries” – hematite concretions – discovered by the Opportunity rover. Photo Credit: NASA/JPL/Cornell/USGS
Opportunity trekked across vast flat plains, drove into deep craters and up hillsides. It found the first evidence for ancient playa lakes on Mars where microbial life could possibly have existed. The “blueberries” it found – tiny hematite concretions – also provided evidence for a once-wet environment.
The rover’s last stop was Perseverance Valley, a shallow creekbed-like feature on the rim of Endurance Crater. Scientists think it actually was likely created by flowing water, or maybe ice, billions of years ago.
Meanwhile, NASA’s other current rover, Curiosity, continues to explore Gale crater, the location of a former lake a few billion years ago. Curiosity was barely affected by the dust storm since it is nuclear powered instead of using solar panels like Opportunity. Unless something bad happens, Curiosity should still have a long life ahead of it.
As the saying goes, “it isn’t over until the fat lady sings.” Opportunity’s official end may be near, but even if it is, it will still be known as one of the most successful Mars exploration missions in history.