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Mars Failures: Bad luck or Bad Programs?
HobbySpacer writes "One European mission is on its way to Mars and two US landers will soon launch. They face tough odds for success. Of 34 Mars missions since the start of the space age, 20 have failed. This article looks at why Mars is so hard. It reports, for example, that a former manager on the Mars Pathfinder project believes that "Software is the number one problem". He says that since the mid-70s "software hasnâ(TM)t gone anywhere. There isnâ(TM)t a project that gets their software done."" Or maybe it has to do with being an incredible distance, on an inhumane climate. Either or.
âoeThe limiting factor in Mars sample return is mass,â he said. âoeDirect return [of samples] from Mars right now exceeds the cost envelope and performance envelope of the available launch vehicles and upper stages.â
The first samples returned should have mystical properties ascribed to them and then sold on EBay. This should generate enough revenue to substantially increase the size of the "cost envelope"...
cheers
(I got engaged last night) =)
Make it simple. The original software used (like in the moonshots) was Very simple control loops... no OS, no overhead.. just a simple program doing a VERY simple job over and over. Read stick, fire retros as appropriate.
Also, solid state, however big and bulky, isn't susceptible to the radiation that many mega-tiny chips are... by writing (and testing) the software in the simplest manner, and building a VERY specific piece of hardware out of solid state components.. and lots of unit testing... you're more likely to get there.
For the same reason the 486 was the only space-rated intel processor for quite a long time (not sure if thats still true).
I'd rather go on "slower" simpler hardware that does a very specific job... and you can repair with a soldering iron.
meh
I think that is part of the difficulty...
With 512 BYTES of ram you can literally look at the entire contents. You can be aware of every single bit on the system.
Now, where we have gigabytes of ram, and even more other storage it is simply impossible to sort through every bit. This errors roll in.
I'm not sure what to do about it, but I see why there is difficulty.
Sticks and Stones may break my bones, but copyright will always protect me.
Well, there are a lot of reasons thing go wrong. Landing a spacecraft on a different planet is inherently difficult, and when you read about how MER-1 and MER-2 will land, it's amazing that they can work at all.
The flip side is that. After Mars Ovserver spectatularly failed in 1993 ("Martians"), NASA started to go with faster, cheaper, better. The idea was, instead of a single $1 billion mission every 5 years with with 90% chance of success, why not 2 $200 million missions every two years, with an 80% chance of success. Everyone loves this idea when it works (Pathfinder), but when a cheap spacecraft fails, the public doesn't care if it cost $10 million or $10 billion, all we know is that NASA is wasting money.
So, the answer is, NASA has hit some bad luck. But the idea of faster, cheaper, better is ultimately a cost-effective one, so if we can solve these software problems (I mean, can't someone independently design a landing simulator?), and NASA can get 80-90%, we'll be getting a lot more science for the dollar. But NASA-haters will always have some missions to point to as a "waste" of money, and try to cut funding as it's mismanaged; other space junkies will insst that anything under 100% is unacceptble, and costs should double to move from 80% to 100%. I don't which attitude is more damaging.
NASA has a "good" track record since Observer, unfortunately, the highest profile missions have generally failed. If MER-1, and MER-2 are both succesful, and SIRTF flies this summer, then everyone should get off of NASA unmanned program's back for a while.
Thing is, space exploration isn't done with *current* technology. The computing technology used in a lot of aerospace applications is 20-30 years old. There are a number of reasons for this, but the ones I've heard of are:
1. The projects are long-term, and have been in development for a lot of years. Especially when it comes to government projects. They can't just up and switch to the latest tech whenever it comes around, otherwise it will end up like DNF and never see the light of day.
2. The engineers don't trust the latest and greatest. The technology isn't considered mature enough. All the bugs have been worked out in the older tech, so it's more robust, the engineers are more familiar with it, and more often than not, manufacturers have shunk and simplified the designs significantly since introduction.
It's more likely that you'd find a 8086 processor in the space shuttle than a Pentium 4 unless someone brings a laptop aboard. It wasn't all that long ago that NASA put adds on websites and geek magazines appealing for old 8086 processors for spare parts. I haven't heard anything since, so either they found a supplier, or they're too busy piecing together the Columbia.
In my years at NASA Goddard I saw a dysfunctional management operate in ignorance of reality.
There was much praise of the employee who "went the extra mile", "put in long hours" and "served the customer" (that applied to contractor employees). There was also very little thought paid to the consequences of those practices.
What's the first thing to go when you're tired? It's not your body -- it's your mind. That's right -- if you're staying at work until you're feeling tired, you're making mistakes that need to be corrected later. The tireder you are, the more mistakes. The tireder you are, the less you can actually do.
I witnessed people who wore their exhaustion as a badge of honor. And, when they got into management, insist that others emulate their bad example. The result that I saw was people who should have been kept out of management becoming increasingly dominant. This was accentuated by the "faster, better, cheaper" ideology promulgated by former NASA administrator Goldin. This ideology was used to get rid of more experienced (and thus costly) people who were aware of the consequences of trying to squeeze more work out of fewer people.
It could take a long time for NASA to recover from this culture. The failure of projects in the past few years, the crash of Columbia could be turning points -- or they could be used by incompetents to justify even more dysfunctional behavior.
"Beer is proof God loves us and wants us to be happy." -- B. Franklin
I've seen the code for some MAJOR blue chip companies and I really do wonder how these people stay in business with the rubbish that they put out. For example some of code drops from our clients don't even compile! The reason for all the crap is that it's very easy to cut corners without it being very obvious immediately. Typically, the first thing that gets stopped when things ar getting tight (either time or money) is documentation, quickly followed by testing. Next it's individual features, removed from the requirements 1 by 1.
Since software engineering is still a 'black art' as far as most traditional engineers and project managers are concerned, there isn't the real intuition/understanding of when things are starting to look bad. Without looking at code AND knowing something about it, you won't stand a chance 'intuiting' whether or not things are going well.
Writing software is an expensive business in both time and money. It's also a very young business without the same 'discipline of implementation' as other areas. Until the process matures and people realise that doing it on the cheap gives you cheap software, things aren't going to change and Mars probes are going to continue to produce craters.
Space Exploration isn't easy.
Look at the Space Shuttle. The space shuttle has never had a catastrophic computer failure-- but every line of code on that truck has survived review by a group of programmers. They've examined it, line by line, multiple times, in order to ensure that it's exactly right, because the cost of failure is 7 astronauts and a multimillion dollar orbiter.
The new Mars programs, however, are part of the streamlined "do it on the cheap" NASA. NASA put the Mars Rover down using mostly off-the-shelf and open-source software and a small amount of home-brew stuff. No matter how good open source software gets, it still hasn't undergone the level of review that the Space Shuttle code has seen. No matter how popular an off-the-shelf package is, it's not cost-effective for the manufacturer to give it that sort of treatment. NASA can't afford to do that level of code review because that costs them the ability to do some other program.
NASA is simply trying to do more with less in the unmanned launches, and the cost of that is we need to expect some failures. These failures are unfortunately very visible...
-JDF
Since metric is the standard, there is no conversion needed. It's those damn silly imperial measurements that the Americans still use that causes the problems. Put it this way, we (the British) invented them, if we were willing to bin them decades ago in favour of something the French invented, they must have been really bad.