Opportunity
NASA’s Opportunity Rover Mission on Mars Comes to End
“It is because of trailblazing missions such as Opportunity that there will come a day when our brave astronauts walk on the surface of Mars,” said NASA Administrator Jim Bridenstine. “And when that day arrives, some portion of that first footprint will be owned by the men and women of Opportunity, and a little rover that defied the odds and did so much in the name of exploration.”
NASA to Share Results of Effort to Recover Mars Opportunity Rover
“NASA will discuss the status of its Mars Exploration Rover(MER) Opportunity in a media briefing at 2 p.m. EST (11 a.m. PST) Wednesday, Feb. 13, from the agency’s Jet Propulsion Laboratory (JPL) in Pasadena, California. The briefing will air live on NASA Television, the agency’s website and YouTube. The briefing will follow NASA’s last planned attempts to communicate with Opportunity late Tuesday evening. The solar-powered rover last communicated with Earth June 10, 2018, as a planet-wide dust storm was blanketing the Red Planet.”
Taking In The View From Wharton Ridge, earlier post
“Today I learned that a feature on the surface of Mars has been named after a friend of mine. This was not unexpected since I knew that his name was in the queue waiting for just the right feature to be discovered by the Opportunity rover. “Wharton Ridge” is named after Robert A. Wharton (Bob). Bob was born a few years before me in 1951 and died unexpectedly in 2012. I worked with Bob at the old Life Sciences Division at NASA Headquarters in the late 1980s. … Bob would have been in his element on Mars. He was perfectly suited for it. When we do send people to Mars they will truly be following in his footsteps. In the tradition of polar explorers Bob’s colleagues waited until just the right place revealed itself to them. As Opportunity made its way down into Endeavour Crater via Bitterroot Valley to Spirit Mound it passed Wharton Ridge.”
Girl with Dreams Names Mars Rovers ‘Spirit’ and ‘Opportunity’
“Twin robotic geologists NASA is sending to Mars will embody in their newly chosen names — Spirit and Opportunity — two cherished attributes that guide humans to explore. NASA Administrator Sean O’Keefe and 9-year-old Sofi Collis, who wrote the winning essay in a naming contest, unveiled the names this morning at NASA’s Kennedy Space Center. “Now, thanks to Sofi Collis, our third grade explorer-to-be from Scottsdale, Ariz., we have names for the rovers that are extremely worthy of the bold mission they are about to undertake,” O’Keefe said.”
Keith’s note: At a 2003 press event at NASA HQ I asked NASA Science AA Ed Weiler what would happen if some martian wind blew the dust off of the solar panels and the Mars Rovers had some extra time to do things. He thought my question was silly. Silly me.
It’s pining for the fjords
One of space explorations most outperforming tools ever…. If only they all would be built to perform this well nominally.
Actually this has been a common feature of the robotic missions. Look at New Horizons, the Voyagers, LRO, Galileo…
Yes, but there is a great difference in difficulty between a surface mission and a satellite.
Yes, and NASA has a excellent record with rover missions. Every one has been a success. Sojourner Truth was designed to last only a week and it operated for nearly 3 months. Curiosity which landed in 2012 for a two year mission is still going strong.
Actually, I think every NASA Mars lander or rover has significantly exceeded its design lifetime (at least the seven that lander intact…) Even Phoenix, with a hard limit from polar winter and using solar power, managed about twice its planned 90 days of surface operations.
RIP MER-B
I’d argue that Opportunity was, at least in a certain sense, a failure.
If that comment is maddening, let me explain: in what sense is a device that is to work for 90 days but works 15 years not abysmally over-engineered? What’s the cost of that engineering? In time and dollars?
“Lots of unknowns”, you might say.
“We don’t have much experience with this sort of thing”
“The cost of the launch is so high it’s best to take no chances”
“We can’t take chances!”
“Because space is hard!”
All true.
I have been a designer my entire adult life. Designers live, and sometimes fall, by establishing and demonstrating congruence between the final project and project program or goals.
Oppy’s program? Stay alive for 90 days; Assure the suite of instruments function properly. In this, the project succeeded. But in lasting 60 times longer, did we over spend?
The final project assessment report (does such a critter exist?) should focus, not so much on how long the device functioned, but on the procedures, or materials that were used and could have been avoided. “Where did we spend money, or spend time, that could have been avoided, bringing the project closer to the design goals?”
Michael,
Opportunity’s ‘program’ was to make discoveries about water on Mars. The design accomplished this in spite of the ‘givens’ being very loose in the precise particulars.
It’s one thing to design something to last a certain time here on Earth on the foundation of a history of living here on this planet and building things here on this planet.
It is quite another to design something to operate even for 90 days in a place (and I use the term loosely since such phrasing presumes broad similarity of characteristics) where we’ve only landed a dozen or so pieces of equipment…and THAT after surviving an ~8-10 minute high-thrust rocket ascent from the Earth’s surface, a deep-space flight lasting ~six months, a scorching interplanetary-speed re-entry into a different planet’s atmosphere, and then an air-bag-bouncing arrival onto a new never-touched region of another planet.
Consider Curiosity, Opportunity’s ‘big brother’: it’s wheels are breaking/chipping/flaking and this is affecting operations. Those wheels, derived in part from the MER design, were designed inside a very tight ‘Venn diagram’ of competing constraints. Should they have been more ‘over-designed’ than they were, or less so because they’ve lasted this long already?
Where exactly should the engineers, millions of miles away from the actual operating theater in an entirely different environment, trim their designs and then still be confident that the mission could execute its program at all?
I do indeed appreciate your sentiment (Why could I learn to effectively use a back-hoe in a day while it takes months to train an astronaut to operate the Canadarm?), but I think it is misplaced here.
That’s not quite the situation for the MER rovers. Correct or not, they assumed that dust on the solar arrays would be the life-limiting factor, and that this would end the mission after 90 days. Everything else was good for much longer than that assumed limit. (And that limit was, by definition, since the vague, level zero requirement to “make discoveries about water” was translated into a lower level requirement of 90 days of surface operations.)
They could, in theory, have saved some money on _not_ using a RAD6000, because a 90-day mission would clearly not come close to a 100 krad total integrated dose. The design was probably full of similar choices, so it’s worth asking how much could have been saved if everything had been designed to 180 days on the surface. (E.g. planned duration times a factor of two.)
On the other hand, the RAD6000 was a known and tested processor, and they had it available. It isn’t clear if there was a comparable 25 krad (or 10 krad) rated processor. It probably wouldn’t have been one JPL had used and flown before. Just because they didn’t need anything close to the rated TID, it was probably just easier and less expensive to use one. Finding and qualifying something else would have had a cost of its own, as would redesigning the rest of the flight computer around a non-heritage processor.
It’s interesting. According to this:
https://mars.nasa.gov/mer/m…
they expected that, due to dust accumulation and increasing distance from the Sun, the MER solar panels likely would be generating 50 watts after 90 days. That’s down from 140 watts at the start, or ~36% of starting power levels.
However, it’s mentioned here:
https://mars.jpl.nasa.gov/m…
that on Sol 1809, only 25.6% of the available solar energy penetrated the dust. Presumably that means the solar panels are generating no better than ~36 watts, yet it’s stated that MER-A was able to operate normally, and drive, under those conditions.
So obviously there was some margin there even without dust cleaning events…. not 15 years worth of course.
Also, even with too little energy to drive meaningful distances, the MERs would be able to continue to operate as a lander for some period of time.
So I imagine folks expected to be able to operate a few months past the 90 days even with no dust cleaning.
The question is really about marginal cost. It is also about reducing the risk of failure. How much more did it actually cost to “over design” it? And what would have been the probability of failure at the start of it wasn’t built so robust?
All excellent follow-on questions for sure.
“what would have been the probability of failure at the start of it wasn’t built so robust?”
That is exactly the question that needs answering. And it is particularly acute in this case where a machine lasted sixty times longer than required. These are very expensive machines and that is a hell of a miscalculation. It should be correctly labeled as a mistake equal to the “units fiasco”. It just isn’t acceptable. Dollars are scarce.
And this: sure, the main goal involved water. But isn’t the incremental acquisition of mission-design knowledge part of the goal as well?
I took a course in land development accounting way back when. The professor pointed out while reviewing double-entry that any deviation from an exact match was bad. Mistakes benefitting the client, or hurting the client, are exactly the same: they are indicators of a deeper and unseen problem.
I think there are two issues here.
First, there are the odds of failure as a function of time. Does a part fail the minute the warrantee expires? Or is it the sort of thing which tends to fail either in the first month or not for years? If it’s the former, then you could really design for a 90-day mission and not waste resources on making it last for a decade. But if it’s the later, then just making it last for 90 days almost inevitably means it will keep going for years, and there aren’t meaningful savings from designing for 90 days. Some parts are of one sort and others of the other sort. But it takes use and experience with the parts to know which is which. When it comes to planetary spacecraft, we’re still learning.
Second, if I’ve got a good part which I’ve used before and I know it’s good for the job, it makes sense to use it. It might be overkill and might be rated to work for a decade rather than a few months, but I’ve got it on the shelf. No cost to design and develop a new one. No worries (or lengthy tests) concerning how reliable the new design will be. That’s a justifiable reason to fly parts which are more capable that the requirements actually call for.
I believe the 90 Sols was thought to be enough to accomplish the mission success criteria. That’s typically a fairly low bar… e.g., take a 360° panorama, drive 100 meters (I just made that up, I don’t recall MER’s mission success criteria). It’s enough to say the mission achieved minimum science goals (or engineering goals if there is some tech being demonstrated). Of course scientists/engineers always hope/want to do more…
It may be worth mentioning that Sofi Collis, the nine year old student who suggested the names Spirit and Opportunit, would now be twenty five. I wonder what she is doing and what she thinks of the end of their work on Mars.