A Heartfelt Goodbye to a Spirited Mars Rover

[PPI Brian]

Mars Exploration Rover Project Manager John Callas sent this letter to his team shortly after the final command was sent to the Mars rover Sprit, which operated on the surface of Mars for more than six years and made numerous scientific discoveries.

Dear Team,

Last night, just after midnight, the last recovery command was sent to Spirit. It would be an understatement to say that this was a significant moment. Since the last communication from Spirit on March 22, 2010 (Sol 2210), as she entered her fourth Martian winter, nothing has been heard from her. There is a continued silence from the Gusev site on Mars.

We must remember that we are at this point because we did what we said we would do, to wear the rovers out exploring. For Spirit, we have done that, and then some.

Spirit was designed as a 3-month mission with a kilometer of traverse capability. The rover lasted over 6 years and drove over 7.7 kilometers [4.8 miles] and returned over 124,000 images. Importantly, it is not how long the rover lasted, but how much exploration and discovery Spirit has done.

This is a rover that faced continuous challenges and had to fight for every discovery. Nothing came easy for Spirit. When she landed, she had the Sol 18 flash memory anomaly that threatened her survival. Scientifically, Mars threw a curveball. What was to be a site for lakebed sediments at Gusev, turned out to be a plain of volcanic material as far as the rover eye could see. So Spirit dashed across the plains in an attempt to reach the distant Columbia Hills, believed to be more ancient than the plains.

Exceeding her prime mission duration and odometry, Spirit scrambled up the Columbia Hills, performing Martian mountaineering, something she was never designed to do. There Spirit found her first evidence of water-altered rocks, and later, carbonates.

The environment for Spirit was always harsher than for Opportunity. The winters are deeper and darker. And Gusev is much dustier than Meridiani. Spirit had an ever-increasing accumulation of dust on her arrays. Each winter became harder than the last.

It was after her second Earth year on Mars when Spirit descended down the other side of the Columbia Hills that she experienced the first major failure of the mission, her right-front wheel failed. Spirit had to re-learn to drive with just five wheels, driving mostly backwards dragging her failed wheel. It is out of this failure that Spirit made one of the most significant discoveries of the mission. Out of lemons, Spirit made lemonade.

Each winter was hard for Spirit. But with ever-accumulating dust and the failed wheel that limited the maximum achievable slope, Spirit had no options for surviving the looming fourth winter. So we made a hard push toward some high-value science to the south. But the first path there, up onto Home Plate, was not passable. So we went for Plan B, around to the northeast of Home Plate. That too was not passable and the clock was ticking. We were left with our last choice, the longest and most risky, to head around Home Plate to the west.

It was along this path that Spirit, with her degraded 5-wheel driving, broke through an unseen hazard and became embedded in unconsolidated fine material that trapped the rover. Even this unfortunate event turned into another exciting scientific discovery. We conducted a very ambitious extrication effort, but the extrication on Mars ran out of time with the fourth winter and was further complicated by another wheel failure.

With no favorable tilt and more dust on the arrays, Spirit likely ran out of energy and succumbed to the cold temperatures during the fourth winter. There was a plausible expectation that the rover might survive the cold and wake up in the spring, but a lack of response from the rover after more than 1,200 recovery commands were sent to rouse her indicates that Spirit will sleep forever.

But let?s remember the adventure we have had. Spirit has climbed mountains, survived rover-killing dust storms, rode out three cold, dark winters and made some of the most spectacular discoveries on Mars. She has told us that Mars was once like Earth. There was water and hot springs, the conditions that could have supported life. She has given us a foundation to further explore the Red Planet and to understand ourselves and our place in the universe.

But in addition to all the scientific discoveries Spirit has given us in her long, productive rover life, she has also given us a great intangible. Mars is no longer a strange, distant and unknown place. Mars is now our neighborhood. And we all go to work on Mars every day. Thank you, Spirit. Well done, little rover.

And to all of you, well done, too.

Sincerely,
John

[PPI Karl]

I read this on-line yesterday, too, and it got to me as well.  I'll always picture in my head the Spirit Rover on the lip of a crater, irrevocably exiled to Mars like a gulag in the Arctic Circle.  I know I'm anthropomorphizing it, but it's difficult not to relate to it as a pet when you call something a "Rover."  I think a lot of people who respect the risk of exploration and revolution in scientific discovery identify with it in all its isolation.  It sort of feels like this sacrifice of an intelligent machine represents our own sacrifices over the millennia.

Good girl, Spirit.  Rest now.  (

[PPI Tracy]

It's amazing the things our space program has done.  We have accomplished so much yet we have not even scratched the surface.  The possibilities are endless.  This letter leaves me speechless.  What a wonderful, heartfelt, yet bittersweet farewell to Spirit.

Thank you for posting this, Brian.

[PPI Tim]

When is the next mission to Mars?

[PPI Brian]

The Curiosity Rover has a tentative launch date of late November or early December of 2011. It's a bigger, badder rover.  

http://en.rian.ru/science/20100521/159104459.html

[PPI Tracy]

Now THAT is AWESOME!

[PPI Brian]

Curiosity will not use the airbag landing method developed by Pathfinder and perfected by Opportunity and Spirit. Here's a video that shows how they intend to land the new rover in 2012:

http://www.youtube.com/v/BudlaGh1A0o

[PPI Tim]

I don't think that this rover is going to make it. I think that NASA has spent millions of dollars to make a new crater on Mars because after this thing fails to land properly, that is all that going to be left....a crater.

[PPI Tracy]

Nooooo....don't say that, Timmeh!

[PPI Tim]

They are not taking the tryed and true approach with the next probe. Spirit rovers performed wonderfully after they landed by bouncey ball why not use it technique again?
I won't be surprised if they have problems with this probe.

[PPI Jason]

They are not taking the tryed and true approach with the next probe. Spirit rovers performed wonderfully after they landed by bouncey ball why not use it technique again?
I won't be surprised if they have problems with this probe.

It seems to me liket they may be using this as an opportunity to test technology that may help in landing people on Mars someday. Afterall, you're not going to land astronaughts on Mars, or the moon, in a bouncy ball.

It just think it's kind of ironic. All those people accused martians of coming here to Earth to anally probe us. Now look whose doing all the probing 

[PPI Jason]

Well, I wasn't saying it as a joke.

NASA has regularly used newer techniques in their exploration efforts that would either come into play later (like the way they used the Gemini and earlier Apollo missions to very gradually phase in technology that they would later need to land on the moon).

But thanks for laughing at my non-joke.

Take care Everyone,

[PPI Brian]

I'm sorry if I offended you, Jason, because that was not my intent. I wasn't laughing at you, I was laughing at your anal probe joke. Looking back at my comment I can see that I should have spent a few seconds longer composing it, because it didn't read right. Sorry about that. I will delete it.

[PPI Karl]

I found this interesting article this morning.



Discovery of Deepest Worms Holds Promise for Mars Life
Stephanie Pappas, LiveScience Senior Writer
Date: 03 June 2011 Time: 03:57 PM ET

The nematode H. mephisto lives nearly a mile (1.3 km) underground in rock fractures near South African goldmines.
CREDIT: Property of the University Ghent, Belgium - Gaetan Borgonie

How low can worms go? According to a new study, at least 0.8 miles (1.3 kilometers) below the Earth's surface.  That's the depth at which scientists discovered a new species of worm, dubbed Halicephalobus mephisto in honor of Faust's demon Mephistopheles. The worm, reported this week in the journal Nature, is the deepest living multicellular organism ever found and opens up the possibility that multicellular life could lurk below the surface of a planet such as Mars.  "We tried to get the title of the paper to be 'Worms from Hell,'" said study author Tullis Onstott of Princeton University. "But Nature didn't go for that."

The Moby Dick worm
Onstott and his colleagues have been searching for subsurface life for 15 years, focusing on the ultra-deep mines of South Africa, which penetrate more than 1.8 miles (3 km) into the Earth. They and other teams of scientists have found that life has very deep roots, with single-celled organisms found miles underground. Some of these organisms are quite extreme: One 2008 study found life thriving a mile under the seafloor, surviving in temperatures between 140 and 212 degrees Fahrenheit (60 and 110 degrees Celsius).  But finding the multicellular, 0.02-inch-long (0.5 millimeters) H. mephisto is a different story. The worm, or nematode, lives in fluid-filled rock fractures, where it grazes on bacteria, Onstott told LiveScience.  "It's kind of like finding Moby Dick in Lake Ontario," he said. "It's so volumetrically big. It's 10 billion times the size of the bacteria upon which it feeds."

To find the worm, Onstott and his team sampled water from mine boreholes as deep as 2.2 miles (3.6 km). They also sampled soil around the mine boreholes and filtered about 40,000 gallons of surface water to ensure that the nematodes weren't coming into the mine from above.

In the Beatrix gold mine, they found their quarry: the tiny, simple nematode, alive and capable of asexual reproduction. The researchers were able to get H. mephisto to reproduce, and the species is still "squirming around in the lab," Onstott said.

The researchers found no evidence of the nematode in surface waters or soils, indicating that it is native to deep rock fractures. Chemical analysis revealed that the water in which H. mephisto lives dates back at least 2,900 years, meaning it's been down there for a while, said Rick Colwell, a microbiologist who studies subsurface organisms at Oregon State University. "They have been quite careful in measuring the environment that these organisms come from," Colwell, who was not involved in the study, told LiveScience.

In lab experiments, the research team found that H. mephisto prefers to snack on the bacteria found in deep rock fractures, turning up its wormy nose at aboveground buffet options such as E. coli.

Worms in space?
The find could encourage researchers to expand the search for life under our own feet, said Colwell, who along with others is working on a project called the Census of Deep Life, dedicated to cataloguing what lies beneath Earth's surface. "As we initiate this census of deep life," Colwell said, "I can see expanding it in the direction of some more complex life forms, like these nematodes."

Farther from home, the discovery of very deep multicellular worms opens up possibilities in the search for extraterrestrial life, said Michael Meyer, the lead scientist for Mars exploration at NASA, who was not involved in the study. Researchers have assumed that any subsurface life on a planet like Mars would be unicellular, Meyer told LiveScience. "This kinds of opens it up to, well, even multicellular life could be possible," Meyer said.

[PPI Brian]

Thank you for sharing this article with us, Karl. I find the possibility of life on Mars, past or present, endlessly intriguing. The Mars Exploration Rovers discovered geologic evidence of large amounts of liquid water on the surface of mars in the past. Life as we know it needs liquid water in order to survive. How long did this water last, and was the enviornoment stable for a sufficient length of time to allow life to develop? Where did that water go? Mars Express and Mars Global Surveyor discovered evidence of active glaciers on the surface of Mars. In the Tharsis region of Mars, volcanoes such as Ceraunius Tholus show evidence of glacial melt water forming a glacial lake associated with volcanic activity. If one of our rovers stumbles across a fossil of a clam shell in one of these ancient lake beds or the ancient sea floor sediments of Meridiani Planum, how would such a discovery affect our religious belief systems? Would they embrace it as evidence of God's grand design of the universe, or dismiss it as a threat to their organizational structure? Personally I don't see how such a discovery could pose a threat to any belief system. It should enrich their spiritual teachings, and reaffirm the miracle of life we take for granted each and every day on our own planet. But something tells me that won't be the case. I think it took the Catholic church 400 years to acknowledge that Galileo was obviously correct when he said the earth orbited the sun, not vice versa.