What did Opportunity’s ‘last words’ actually mean?

Jason Rhian

“My battery is low and it’s getting dark.” This supposedly was the last message sent back to mission controllers on Earth by the Mars Exploration Rover Opportunity. But is this actually what she “said?”

Jacob Margolis, a science reporter with KPCC, tweeted a paraphrased version of what John Callas, the mission’s project manager, had said regarding the contents of Opportunity’s last update that the rover sent back on June 10.

Obviously, the robotic geologist, which touched down at Mars’ Meridiani Planum in 2004, did not “speak” like people do. However, the general public is not able to parse the lines of code, the fault readings and measurements Opportunity sent back to NASA’s Jet Propulsion Laboratory in California. The public needed to have that information relayed to them in a way they could understand.

They also are unlikely to know that when Opportunity sent her updates back to Earth, that these streams of data had to be transmitted up to one of the spacecraft orbiting Mars (either the 2001 Mars Odyssey or Mars Global Surveyor spacecraft) and then to Earth via the Deep Space Network.

Mission planners for NASA’s Mars Exploration Rover program estimated that each of the two rovers would last about three months. They severely underestimated their creations’ perseverance. Spirit was active, either roving or as a stationary scientific platform on Mars for about six years. Opportunity? It took a dust storm that blanketed the entire planet to end her mission after 15 years of service.

“Opportunity was kind of like a family member and this last ‘message’ was sad, but I knew it had a great life,” Carleton Bailie, a photographer who covered the mission for Boeing told SpaceFlight Insider (Bailie provides his images to SpaceFlight Insider).

NASA knew the dust storm spelled trouble for the solar-powered rover. After the agency lost contact with her – they endlessly tried to get her wake up but were forced to accept that she was gone. The official announcement was made on Feb. 12, 2019.

This storm was the (Martian) real deal. The first signs of what was coming started in late May of 2018. By June the storm had covered Mars (and it didn’t wane until mid-September). Opportunity was a fighter and it took one hell of a storm to finally take her out. The storm was possibly the worst seen by NASA since the agency first began observing them in 1971 when the Mariner 9 probe was in orbit above Mars.

“Once every three Mars years (about 5 and a half Earth years), on average, normal storms grow into planet-encircling dust storms, and we usually call those ‘global dust storms’ to distinguish them,” said Michael Smith, a planetary scientist at NASA’s Goddard Space Flight Center.

It wasn’t powerful winds that threatened the rover as Martian winds likely top out at about 60 miles (97 kilometers) per hour. It was the dust. With its solar panels covered, Opportunity entered a low power fault mode. In this mode the rover’s subsystems, except its mission clock, were turned off. Opportunity’s mission clock was designed to wake the computer to check her power levels. At some point, this stopped working and Opportunity never woke up.

“To be honest, I was surprised – and rather touched – by all the attention given to Opportunity’s after we lost communication with her. Plenty of people who I didn’t think were really into space, or paying attention to space news, were talking about how sad it was that this lonely rover had been working on Mars for 15 years and then fell silent,” Jay Gallentine, the author of Ambassadors from Earth told SpaceFlight Insider.

The data that comprised the last message Opportunity transmitted back to Earth was actually a regularly-scheduled status update. It contained, among other things, two equipment measurements – her battery’s power was dropping due to the high volume of dust in the air and that it was receiving low light on her solar panels. In other words, its battery was low and it was getting dark.

Margolis got it right.

During her decade-and-a-half collecting bits of information, covered in Martian dust, the rover acquired a fan following that some celebrities would envy.

So, while Opportunity’s final update might not have been a dire plea back home, it helped demonstrate that, in the eyes of some, the rover had a life of its own. This certainly was the case for those who tended her, some of whom wept when they accepted she had fallen asleep for the last time.

For those directly involved with exploration of the solar system the real message is written in the miles of Martian sand Opportunity explored (28.06 miles or 45.16 kilometers).

“Opportunity was an amazing explorer. the gift that kept on giving more than 50 times as long as originally planned. We miss her already,” Alan Stern, the Principal Investigator of the New Horizons mission told SpaceFlight Insider.

Video courtesy of NASA

The views expressed above are those of the author and do not necessarily reflect those of SpaceFlight Insider