Yesterday was the fifth anniversary of the arrival on Mars of the Mars Exploration Rover Spirit. Despite a few problems to do with their age, both this rover and its identical twin Opportunity are in good working order and are still wandering around the surface of Mars and sending back interesting findings.
The obvious first thing to do is to congratulate everyone who had anything to do with these missions for a truly magnificent achievement. During my life, watching NASA’s manned space program has been intensely frustrating. Huge amounts of money have been spent on overly expensive boondogles that achieve less than was achieved in the years around the time I was born, despite there being no shortage of new and exciting things that could be achieved. At the same time, though, and on vastly smaller budgets, the unmanned probes produced by and with NASA/JPL to explore the planets and the solar system have managed magnificent achievement after magnificent achievement. Since I was a child we have learned so much about the planets and the solar system, and I have found it hugely inspiring. Seeing high resolution photographs of the moons of Saturn, or the surface of Mars, or the Great Dark Spot of Neptune – who would have imagined such things.
And yet, one thing that amazes me even more is the strange way in which NASA planetary probes stretch and warp time. For instance, the two Mars rovers were sent to Mars on missions that were supposed to last for 90 days. Both missions are now at five years, which is a little over 20 times the original length of the mission. This is an extreme example, but these missions often dramatically outlast their stated lifetimes. A four year Mars Global Surveyor mission turns into nine years. The Cassini mission to Saturn has been there for the planned four years, has had its funding extended for another two, and may manage more than that.
One reason why missions are able to be extended for long periods is of course the extraordinary ingenuity of the people who run them. That software is being upgraded and hardware used in unplanned ways to fix all manner of problems with stuck robotic arms, failed high-gain antennas, wheels getting a little sticky, rovers stuck in sand-dunes, and that these things so often seem to work is another thing that amazes me.
Yet, I wonder further. Clearly, when these missions are launched the hope is that they will keep going a lot longer than stated in the “mission objectives”. Clearly, also, in many cases the principal scientific goals will be achieved in the first few days or months after arriving at the destination, so what decides success is what happens shortly after arrival. Arguing that “everything else is a bonus” after the core objectives are achieved is probably fair.
How much of it is politics, though? I am sure it is easier to get funding for a five year old mission on the basis that “We have a rover on Mars that is still working and it would be a horrible shame to end the mission now” than asking for six years of funding at the beginning. I am sure also that when scientists are told that “You can’t have funding for A, B, C, and D, but we will give you funding for A and B”, they will find a way to include C and D while pretending that A and B is all they are doing, particularly if A and B are Jupiter and Saturn, and C and D are Uranus and Neptune.
And yet, when a 90 day mission is still going after five years, I cannot help but think that someone, somewhere, is taking the piss out of someone. All I can ask is that they please keep doing it.
I think they just tend towards low expectations to avoid embarrassment. If a rover on a 5 year mission conks out after 90 days, it looks like a failure. If a rover on a 90 day mission lasts 5 years, it’s a spectacular success.
Me, I can’t help wondering though whether, if there’d been no nationalised space programmes, we’d now have cheap, private sector probes swarming all over the solar system instead of a small number of probes, the failure of which spells disaster. (I come out in hives every time I think of New Horizons failing just as it arrives at Pluto).
Of all the wasteful government programs, I admit that NASA is by far my favorite one.
I fear it may be our regret that we have to end NASA to deal with our unfathomably massive fiscal, monetary, trade and leadership deficits. That’s a pity. NASA is the only agency or program I can think that has really demonstrated some of the greatest aspects of mankind.
Excellent blog, sir!
Add to this the Pioneer missions–launched by the parents of the people on them now.
A lot of it is simply engineering margins. If you build a vehicle with sufficient engineering margins to have a very high chance to survive for some period of time then very often you end up with a vehicle that can survive at the edge of the margins for much longer. I have been an avid study of robotic spaceflight and I can tell you that these vehicles are not covertly designed for longer missions. Each vehicle has been dangerously close to death many times during their prime and extended missions (the Mars rovers, Galileo, the Voyagers, and SOHO are excellent examples).
Also, for every spacecraft that vastly exceeds its original mission plan there is another that has failed either partly or completely.
I am sure also that when scientists are told that “You can’t have funding for A, B, C, and D, but we will give you funding for A and B”, they will find a way to include C and D while pretending that A and B is all they are doing…
I suspect that they would do exactly that, as well as spinning A-D in the most attractive way for the potential funding body, i.e. if they can link it to whatever is currently fashionable without it looking contrived then they’d do so.
Survivor’s bias.
The greatest survivor is the ESA/NASA SOHO probe which has lost all its gyros and has gone through lots of other problems and is still functioning and sending back data that indicated that climate change may be caused by something other than little old ladies driving SUVs.
A nice strategy, but now that its clearly understood that devices sent to Mars can and do regularly last for years in that harsh environment, why would anyone now agree to fund a mission with only a 90 day timeframe? Wouldn’t you demand that any mission to Mars have an expectation of atleast 5 years of active service?
I think the folks over at JPL subscribe to the Montgomery Scott school of space exploration. Promise a little, delver hugely. Presto, you’re a miracle worker. 🙂
Put JPL in charge of NASA.
I attribute their longevity to the friendly climate and life-giving waters of Mars, the Planet of the Future…
Remember, as the US marches in lockstep towards our Golden Socialist Tomorrow: When you run out of America, you’re plum out of planet!
Many here are forgetting that the 90 day lifetime for the Spirit and Opportunity surface ops was based mainly on a prediction that the solar panels on the rovers would take on enough wind blown dust such that the rovers would no longer be able to charge their batteries. We did not know the Martian winds and dirt devils would regularly clean the panels enabling years of battery life.
Many here are forgetting that the 90 day lifetime for the Spirit and Opportunity surface ops was based mainly on a prediction that the solar panels on the rovers would take on enough wind blown dust such that the rovers would no longer be able to charge their batteries. We did not know the Martian winds and dirt devils would regularly clean the panels enabling years of battery life.
TO: All
RE: Five Years and Millions of Miles….
….without a service stop.
When is JPL going to start making the Great American Automobile?
Regards,
Chuck(le)
The original case of that was Voyager 2. The official authorization for the Voyager project was to visit Jupiter and Saturn. But Voyager 2 was launched in time to do the “Grand Tour”. After the Saturn encounter, when funding ran out, NASA was able to go to Congress and get funding for Uranus “since the probe is going there anyway”. And again, later, for Neptune.
Part of it is luck. The solar arrays accrue dust with time and lose efficiency and ultimately can’t power the rover. Some well-timed windstorms blew off the arrays and allowed the rover to continue operations.
The timing, IMO, is an honest guess, and with a little luck and ingenuity, an honest guess can be extended to an amazing working lifetime.
I was working at JPL when the first rover landed so successfully on Mars. Naturally, everyone who worked on the project was elated from the success. One surprising thing was the outpouring of public support. The front office started receiving checks from people all over the country who, along with the donations, wrote notes along the lines: “This is the kind thing I’ve been wanting our space program to do for years!”
Unexpected lifetimes is the result of an accumulation of failure probabilities. These systems are vastly over designed because, obviously, one failure can doom the entire (very expensive mission). The mission is designed around the conservative estimate of when any of the thousands of critical component. Even if each component has only a slim chances of failing after 90 days, the culminative odds are enough to predict failure at that point. However, you only need each part to function close to its most probable lifetime to get operational lifetimes vastly in excess of the conservative estimate.
Just out of school about 10 years ago I worked as a contractor on a NASA program. I’m no expert on all programs or on the culture itself but I was taken under the wing of one of the old engineers there. One of the first things he taught me was “It’s all show biz” if the camera shows a success then it is, the science is secondary and only there so that we have something to talk about on the camera. So in the case of the mar rover you build in a lot of margin just in case. You can’t say it Will last 5 years because the chance of you looking like a failure is too high, so you build it to last and hope it does. I use to call this “aim low and shoot high” They didn’t KNOW that dust would be cleaned off the solar cells by wind, but they build it so that if it did it would still work. Because if you design the system right that doesn’t cost you anything and can have big payoffs.
At least when I was at NASA the view was that small projects were far easier to get funded. And extensions of successful programs are far harder for Congress to kill.
Congress passes the budget late each year and views NASA as a luxury, so getting a big chunk of money means much debate and high risk. Even if you get a big budget it’s difficult to spend in the shortened budget year, and if you don’t spend it you won’t get it renewed. And it might not be renewed by the next Congress, too, so spending it to do a big multi-year project is hard.
Big NASA projects (the Shuttle, the ISSS, etc) are notoriously difficult to work on because the funding is so variable and the sums so large that everyone in Congress plays politics with them.
I’m just happy they finally figured out how to get the conversion between metric and english units correct!
What a stupid idea. NASA takes up a tiny sliver of federal expenditures. Ending it would barely make a dent in the budget. Moreover, you’re just talking money, not capital. There is nothing “unfathomably massive” about the sums involved for modern computers to handle. The US is a very wealthy nation, and will be for the foreseeable future regardless of the dynamics of money. It’s wealth is in its people, in its industrial plant, and in its intellectual capital, not in little green pieces of paper.
“When is JPL going to start making the Great American Automobile?”
–I’ve been hearing a lot of this lately. People forget that auto companies and their subsidiaries were a big part of the space program, and were mightily proud of it. Corporate management has changed, of course–plus, we hate ourselves and our industrial heritage wholeheartedly–but whenever I see a photo of the Lunar Rover, my heart is warmed by the memory of the on-board components made by Studebaker. Philco-Ford, GM-Delco and Chrysler-Motorola were cutting-edge innovators in electronics, and S-P’s composites firm still makes missile parts today.
When the Chinese go to the moon, they should take jumper cables. If it’s anything like other American vehicles from its era, it ought to start right up.
SDB: My examples for “A”, “B”, “C”, and “D” in the second last paragraph were chosen very carefully.
Ryan: The thing about the “It’s all showbusiness” sentiment is that I think it is less true than many of the people in charge think it is. The missions that have the most support amongst interested laymen are precisely those that do the best science. JH’s description of the public reaction to the Mars Rovers is one example, and the considerable public outcry that led to a reversal of the decision not to send another servicing mission to the Hubble Space Telescope is another. Basically, I think it is foolish to underestimate the intelligence and sophistication of the public on issues of this kind.