Mars Opportunity rover: Please phone home!
Last summer, with a dense, planet-wide dust storm approaching its position in Mars’ Perseverance Valley, NASA’s Opportunity rover shut down all systems on June 10 and entered hibernation mode. Long after the dust storm settled, NASA engineers have yet to hear back from Opportunity months after it went stopped sending signals back to Earth.
“Over the past seven months we have attempted to contact Opportunity over 600 times,” said John Callas, project manager for Opportunity at Jet Propulsion Laboratory. “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.”
Initially, NASA engineers use NASA’s Deep Space Network to ping the rover during scheduled “wake up” windows. They also sift through radio signals emanating from Mars to see if one might happen to be Opportunity’s “voice.” However, the rover still wouldn’t respond.
Now in a final attempt to make contact, the team has begun new transmission strategies to determine if low-likelihood events are preventing the rover from sending signals.
“We have and will continue to use multiple techniques in our attempts to contact the rover,” said Callas. “These new command strategies are in addition to the ‘sweep and beep’ commands we have been transmitting up to the rover since September.”
The scenarios that they are investigating are:
- The rover’s primary X-band radio — which Opportunity uses to communicate with Earth — has failed.
- Both its primary and secondary X-band radios have failed.
- The rover’s internal clock, which provides a timeframe for its computer brain, is offset.
However in order for any of these scenarios to take place, several highly unlikely events would have had to occur. NASA is testing every possible scenario before they finally rule that Opportunity has in fact reached the end of its journey. Also even if the rover does miraculously come back online, there is no guarantee that it will function like it did before.
Finding Opportunity through all the dust
There was a glimmer of hope though on Sept. 20 when HiRISE, a high-resolution camera onboard NASA’s Mars Reconnaissance Orbiter, captured a satellite image showing Opportunity. Look closely at the image above and you can see a tiny white dot in the center of the square. NASA officials said the fact that the rover appears in the image means the dust storm has “substantially cleared.” Now, the waiting game continues to see if Opportunity will come back online.
Unlike the Curiosity rover, which runs off a nuclear-powered battery, Opportunity relies purely on solar cells to charge its lithium batteries. While the rover has endured massive dust storms before, the intensity of this one — described by NASA officials as a “dark, perpetual night” –– coupled with its unprecedented length, could prove to be too much for the plucky little robot.
The little rover that could
Engineered for a mission that was expected to last only 90 days, Opportunity has defied all odds by surviving and conducting explorations on the surface of Mars for nearly 15 years. Even its twin, Spirit, which landed three weeks before Opportunity in January 2004, managed to function until 2010. As it currently stands, Opportunity holds the off-Earth roving record with a distance of more than 28 miles.
The biggest concern facing engineers is whether or not Opportunity’s batteries had enough reserves to help protect its internal components from Mars’ freezing surface temperatures. One of the last signals sent NASA on June 10 showed the rover’s temperature to be about minus 20 degrees Fahrenheit (minus 28 Celsius).
“The rover needs to balance low levels of charge in its battery with sub-freezing temperatures,” the team explained. “Its heaters are vitally important to keeping it alive, but also draw more power from the battery. Likewise, performing certain actions draws on battery power, but can actually expel energy and raise the rover’s temperature.”
While an analysis by engineers of the rover’s systems relative to the freezing cold showed that it had the potential to keep warm for the duration of the storm, the rover’s age makes any positive outcome less than certain.
“It’s like you have a loved one in a coma in the hospital,” Callas told The Washington Post. “The doctors are telling you, ‘You just gotta give it time, and she’ll wake up.’ But if it’s your 97-year-old grandmother, you’re going to be very concerned, and by all means we are.”
Editor’s note: This article has been updated since it was originally published in August 2018.
Mars Opportunity rover: Please phone home!
NASA is making one last-ditch effort to contact the red planet’s longest-serving rover.