Scott Maxwell stared at his bedroom ceiling in the hours after his first drive, restless with excitement. All systems were go, and he'd sent the commands by the time he left the Jet Propulsion Laboratory. Now he was supposed to sleep before his next shift on Mars time. But he knew that on the fourth planet from the sun, the Spirit rover's wheels had started to move.
"I was thinking that at that moment, there is a robot on another planet, doing what I told it to do. I could not imagine going to sleep," Maxwell recalls. "It just blew my mind. And I still think it's amazing that what I do with my day job is reach out my hand across 100 million miles across of empty space, and move something on another planet."
Maxwell is one member of a team of engineers and scientists who have spent nearly a decade working with NASA's intrepid Mars Exploration Rovers, Spirit and Opportunity, maneuvering them across windblown Martian terrain and into groundbreaking new discoveries. Many of them, along with a new cadre of researchers, will also command the new Mars rover Curiosity, set to land in three weeks. That rover is far more complex and more powerful, and designed to last much longer than the twin rovers' initial three-month lifespan. But the MER mission, as it's known, set the stage in many ways — including how to live and work as a Mars rover driver.
The humans do their work in a fairly unremarkable setting, wearing normal clothes perched at normal computers, holding conference calls inside normal cubicles in southern California. Yet they're driving little cars on Mars, an incredible feat that never ceases to amaze team members like Maxwell. It is not easy, neither on the team members' own health — living on Mars time is hell for some — nor on their personal relationships. But ask them, and they'll say it's been the trip of a lifetime.
Waking up to drive a rover on Mars is complex from the moment you hit the snooze button. In the early days of a mission, engineers live according to the Martian clock. A Martian day, called a sol, is about 40 minutes longer than an Earth day, so engineers show up for their shifts 40 Earth-minutes later each day. Mars timekeeping requires some detailed calculations. From the perspective of a rover driver, it's awful — unless you're Maxwell, who claims to love it.
Morning people like Deborah Bass, a scientist at JPL who worked on MER and the Phoenix lander, and Ray Arvidson, the mission's deputy principal investigator, describe Mars time less than fondly. "Oh, it hurts," Arvidson says. "It's like coming back from a trip to Europe every day." Nowadays, the MER team plans ahead so they can work normal Earth schedules, but 300 to 400 people will revert to Mars time and its bizarre timelines after Curiosity lands.
Spirit and Opportunity are solar-powered, so they have to work during the Martian day to ensure they have enough juice. Though Curiosity has a nuclear generator, it, too, will work mostly during the day so its cameras and instruments can see. That means planning is key, according to Bass.
"We want to be ready so as soon as that little spacecraft wakes up on Mars, we have a whole set of stuff for it to do," she says. "We send it at like 5 in the morning on Mars, and that's the start of the day. So we say we work the Martian night shift."
Thanks to Mars time, this makes for some long days and nights, and managers at the Jet Propulsion Laboratory have to make sure people go home to bed. "It is so compelling, it can be challenging to shut it off and go home," Bass acknowledges.
It's also challenging because team members feel real affection for the rovers and each other, and want to be there for every new step. The mission has served as a bedrock for people who have worked together for more than a decade, surviving deaths in their families, divorces and other traumatic experiences. Initially, engineers and scientists were tied to one rover or the other, and came to know them closely, discussing Spirit and "Oppy's" personalities the way the rest of us might discuss our pets.
"They are personalities we imbue them with, but they're not less real for that. If you ever had a first car, and you loved that car — maybe it was cantankerous, maybe it was great — that car is somebody to you. This is like that, on steroids," Maxwell says. "To the extent that you can say this about the rovers — that it has a personality and is 'somebody' — the character that she is, is the product of the whole team that is operating her."
THE DAILY GRIND
Despite all the emotion and excitement, even Mars rover driving starts with meetings. The MER team's morning starts with a planning session; the science team, led by Steve Squyres of Cornell University and by Arvidson, a professor at Washington University in St. Louis, head discussions of what the rover ought to do. Then engineers including Maxwell pass the instructions along to the rover itself. (At this point it's rover, singular, because Opportunity is the only one still functioning; its twin Spirit lost contact after becoming mired in sandy soil.)
"Imagine driving your car to the grocery store with a light time delay like that. Nothing happens for somewhere between 4 and 20 minutes, and when it does happen, you don't know about it, because your rear window doesn't update for another 4 to 20 minutes," Maxwell says. To avoid excruciating waits, the team now programs Opportunity (and formerly Spirit) with a series of tasks, up to three days' worth over a weekend. After so many years, they're confident in the rovers' response times and capabilities, so they don't have to test every little command with exacting detail. The Curiosity mission will do that for some time, though.
Late afternoon rover time, Opportunity stops driving and sends pictures to Earth, using its high-gain antenna and a relay from the Mars Odyssey orbiter. That's when Maxwell and his team get to work for the next day. As they write commands, they can move a virtual rover in a custom-built, video-game-like software platform, which serves as an avatar for the one on Mars. The computer version helps validate the commands.
"When it executes, there's not going to be anybody there to hit the panic button, so anything that might go wrong, we have to think of that in advance," Maxwell says.
But sometimes, Mars throws a curveball, and there's nothing anyone can do.
Both rovers had a few kinks early on; their solar panels filled with dust again and again, and Spirit lost control of one of its six wheels a couple of years into the mission. Some instruments eventually wore down, like the diamond in the Rock Abrasion Tool the rovers used to grind into rocks. But none of these limitations presented serious problems. Then on May 1, 2009, the hobbled Spirit fell into a trap.
"It was like an ice skater might break through the surface; Spirit broke through what looked like this very friendly terrain," Maxwell recalls. "It was softer, fluffier terrain, so it was really hard for her to get traction in."
The team went to JPL's rover test bed, a sandbox with a full-size duplicate rover where they could try some maneuvers. They had a plan in place and started sending commands just before the onset of Martian winter — and then another wheel failed. Still, Maxwell and his team figured out a method that would basically help Spirit swim out of the trap, building a pile of dirt behind it. They made 30 centimeters of progress before the sun dropped too low on the winter horizon, and Spirit's solar panels were tilted the wrong way. Spirit went into hibernation, and as far as anyone knows, she never woke up. NASA sent more than 1,300 attempts to hail the rover before finally giving up last year.
"Victory was within our grasp, but we just didn't have the time. It was devastating," Maxwell says.
The experience sparked Arvidson's interest in the terramechanics of Mars, studying the properties of soil at different depths and under crusts. He's a co-investigator on a new terramechanics experiment using Curiosity, which will use detailed telemetry from the rover to help it plot a safe course, avoiding sand traps like the one that caught Spirit. It will also help scientists understand how crusted soil forms, and their relation to the modern Martian water cycle. It's based on a system Arvidson built to free Spirit. "I decided that will never happen again," he says.
Every two seconds, the system records the rover's pitch, yaw, roll and motor currents, simultaneously building a topographic map. Then these figures drop into a computer model. The Curiosity system will work in a similar manner. Here's an example of the MER project, called Artemis.
Along with helping future Mars missions, all of the rover drivers' work — life on Mars time, late nights and missed appointments — has captured the public's imagination, and served to change the way we see our neighbor planet. No longer is the red planet, named for the god of war, such a foreign place; now it's a dirt-filled, rusty-colored landscape where humans can virtually scamper around. The rovers are just about an average person's height, and they see the world in stereo color vision, as Maxwell points out.
"When you see Mars through their eyes, you're seeing it like you would through your own eyes," he says. "We can't go there yet with our squishy, frail human bodies, but we can send robots that can send you home vacation photos of what Mars would be like if you were there yourself."
Despite all the public's affection over the past decade, the rovers have now slipped from most people's minds, just as regular space shuttle launches sometimes failed to make the newspapers. But Opportunity is still bringing home new discoveries all the time.
"In 1969, we landed a human being on the moon. You go out at night and look at that big thing in the sky — people were walking on that, for goodness' sake. But by Apollo 17, everybody was bored with it," as Maxwell puts it. "So we're not front page news everyday, I get that. But for me, it just never gets old."
Arvidson echoes his sentiment: "We're driving rovers on another planet. How can it not be fun?"
While I'm a mechanical engineer by profession, and I appreciate the fact that this website is "Popular Science", I'm still usually a bit miffed by the uncritical reporting presented in articles like this. On one hand, I would agree that NASA/JPL putting this rover on the surface of Mars and driving it around is a genuine technical achievement. But on the other hand, this project came at a huge cost to taxpayers. And there's no way the minimal amount of real science it has produced justifies its billion dollar plus price tag.
While planetary exploration may seem like a worthwhile use of billions of taxpayer dollars to some academics, in reality these expensive NASA projects have not improved the average person's quality of life one bit.
(Up-front disclaimer: I'm Scott Maxwell, from the article.)
In fact, MER has produced an enormous science return; I'm not sure why you would think otherwise. I've lost count of the number of papers published, but it's many dozens -- and it's in high-end journals such as JGR, Nature, and Science. MER has also helped mint any number of PhDs -- such as, for example, my girlfriend.
The billion-dollar cost of MER, also, should be amortized over the more than eight-year lifespan of the mission. That's about 40 cents per American per year, and dropping the longer we live. For less than the cost of a Mars bar, we bring you Mars. Do you really not think that's a good deal?
Love the comparison, @driver. Have you read The Martian Race? Great book. I actually have a few ideas for mars colonization and for asteroid mining systems (M-type). I was wondering if you could possibly get me in touch with a superior? I am a bit ambitious/insane, but my designs will mos likely work.
Thank you for your comments. YES, it is SO worth a Mars bar to bring us Mars. There are many benefits to society, some intangible, by exploring space in general and Mars in particular. I am all for spending tax dollars for MER and for the Curiosity lander, as I am also in favor of Hubble and the awesome James Webb telescope. We have to keep exploring and expanding our knowledge. You never know when space-bound robots and operators such as yourself might hit the jackpot and find a cure for many of the ills that affect our society. To give up because of a perceived lack of benefit to us all would truly be a tragedy. I am an Aeronautical Engineer by profession but I live vicariously through you and the others who are doing great science and helping to advance the human race and our knowledge of things unknown or misunderstood. Keep up the great work you do. It's appreciated by a lot more people than you could ever imagine.
The lack of appreciation that most americans have for scientists and there priceless contributions to society is sad sure, but mostly surprising. It amazes me that if you go back 120 years, you're in the wild west. Fast forward to today and you're in a completely different and better world. One with indoor plumbing, air conditioning, ceiling fans, ice boxes that make their own ice, microwave ovens, 3d hdtv's, choice of cable/satellite/broadcast tv, vehicles that stream music from satellites, gps systems, cell phones.... I don't want to stop funding scientists. I want to give them more. And I have to make a correction. The MER program didn't *cost* us a billion, we *invested* a billion in it. So, let's not talk as if programs like these are a drain on the economy. There are countless new jobs (and new job titles) because of the hard work of scientists like these through the years.
Knowing that people like Scott Maxwell read these comments, I must say this:
I sincerely thank you, NASA, and other organizations like it, publicly and privately funded, that continue to make meaningful contributions and improvements to our lives, our society, and feeding our thirst for knowledge, even if it goes unappreciated by some (most?).
*their, not there
Thank you @alias, scientists don't get the credit they deserve all that often. For example, Tesla himself is resigned to building massive coils and electrical street-shows, when he really was a brilliant engineer. Edison gets all the credit when it comes to brilliance...
And I like your reference to the W-West, nice touch.
I've been following the Rovers since the beginning and there is one thing I do not understand. Why doesn't NASA put wipers or compressed air or something on them to blow off the dust that collects on the solar panels? This is the main reason they fail.
My children and I appreciate all that scientists do and thank PopSci for sharing this story. I agree that scientists are not given nearly enough credit and praise they deserve. Science has given us jobs, technology like the computer I'm using right now, the refrigerator that keeps our food cold and the heat that keeps us warm at night. As a homeschooling mom, I have my children regularly read the JPL website and Popular Science magazine to spark their imagination and interest in science and the world around them. The investments to science are well worth the future of our children and our planet. Thank you to all the dedicated scientists who are working hard to make our world more advanced, more comfortable and more exciting.
" these expensive NASA projects have not improved the average person's quality of life one bit "
Where did you get the idea that giant leaps in space travel are required to instantly improve the average person's quality of life?!
When regular trips to Mars in 2035 will be part of the average tourist's holiday activity going to Mars the benefits of the Spirit-Opportunity-Curiosity navigating will be obvious.
Of what use are the pyramids for the average Egyptian's quality of life?
I think the greatest benefit the Spiritunity gave us was the knowledge, everyday in the back of your mind type knowledge, that Mars is real. That its surface is very much like that of any rocky desert on Earth. That eventually humans will be walking around on it. Because of the landscape photographs and the donuts Opportunity spun in the sand, and the long wandering trail both rovers left in our earthly psyches humanity has adjusted to the knowledge that Mars is there for us. That alone has sparked more youth based interest in colonization than any marketing program possibly could have.
I sure hope Curiosity survives its trial by fire. How many thousands of fingers do you think will be crossed during its descent?
Those JPL and NASA engineers are truly dedicated. Having to move your work schedule ahead 40 minutes every day is the ultimate in "shift work". That kind of schedule would change your start time by 12 hours (and flip your body clock upside down) every 18 days!
I read somewhere that some of the engineers even have watches that run on Mars time; but by now, there's probably an app for that. :}
Sorry for the tardy delay in responding. In my post I did not claim that space missions like MER did not produce lots of science. What I said was that science had little impact on day-to-day lives of 99.9% of the US population, including the taxpayers that funded it. Publishing scores of technical papers that are only really of interest to other scientists/engineers working on interplanetary space probes, or providing a bunch of PhD candidates a topic for their thesis, is of no real tangible benefit outside of the academic world.
As I noted, I work in the aerospace business. I'm not against scientific advancement. It's just that the billions spent on these Mars missions would have given a better return if applied to improving commercial product technology. For example, a similar amount of private dollars as these Mars missions cost was spent to build the Boeing 787 commercial aircraft. It will produce 10 times that amount in profits, billions in tax revenues, create tens of thousands of high paying jobs, and improve commercial air travel for millions of people.
Much better than getting a Mars bar.
Riff Raff... yeah, why even bother with Boeing 787s though - why not just distribute the money to all the tax payers directly to their bank accounts... by your logic, nothing ever should be done with money but go for the shortest path of least resistance of getting the money straight back in to the taxpayers' hands: well, that's not the point of tax.
Scientific papers are only interesting to the academics, that's true - but that is because only they can parse the information contained and translate it into awesome possibilities for the rest of us. The idea that science journals exist without providing any benefit to humanity is absurdly foolish.
I agree with Scott Maxwell above, and others who have put forth brilliant explanations to how this investment is useful, and what I see in your comments is a resistance to understand and agree simply because of bias.
I suggest that it is important for individuals and nations to devote time to non-money making activities. Otherwise, what are we but economic robots? I would put the rovers in this category: perhaps not the most profitable use of capital but something that makes life richer. There are line items that should take priority over exploratory science such as health, education, defense, and so on. As long as these areas are more or less adequately covered then there should always be a portion of the budget going to scientific discovery.
I would like to ask a question of the experts about future exploration: is it feasible to miniaturize unmanned space vessels? This would appear to be a way of lowering costs and risks--- if the physics of space travel permits the engineering of very small space ships. I'm sure you've already thought about this but it seems that most technologies keeps getting smaller and smaller...