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Hubble Repairs Hindered By Antiquated Computer Systems
Andrew Moseman writes "Part of the trouble NASA is encountering while fixing the Hubble Space Telescope comes from the fact that it's been up there for nearly two decades, and therefore carries computer systems long outdated here on Earth. 'One of the main computers that the Goddard team has been struggling with during the repair attempts runs on an Intel 486 chip, the height of 1989 technology.' Many of NASA's long-running missions rely on antiquated systems — the Voyager probes each have about 32k of memory — but the scientists say they can manage."
well if the Hubble has at least 640k memory it should be fine. . . .right?
Maybe I'm just getting old, but a 486 doesn't seem all that big a deal to me. I mean it's not as if it's a completely different architecture to that in use today.
They need to have the chips hardened for radiation. I'm not sure what the process entails, but they don't seem to do it with chips younger than 10 years or so. /. did a pretty good article on this awhile back I think.
I sent my Amiga 500 into orbit in 2001 using a homemade trebuchet (granted, quite a large one) and a very high mountain. It broadcasts the Pinball Dreams high score list every two hours on the hour. The problem is, the last time I went up to do some improvements (long story) I had forgotten a few vital 68000 assembler directives, so I was unable to make the transition from antiquated late-80s desktop computer to cutting-edge ASAT weapon. Too bad, now the 10kT warhead I attached to it is probably just sitting there, twiddling its sub-critical materials.
I would imagine it's a little more difficult than simply popping out the CPU and putting in a new one. If you were tasked with upgrading a 486 here on Earth, how many components do you think you'd be able to recycle into the new machine? You'd end up replacing the whole thing, maybe keeping the HDD around just long enough to get your data off it.
"I'm not sure I like the fugnutish tone you used in your post!" -RogL (608926)-
I actually don't think you can realistically shield effectively against some types of high energy particles. Nuclear reactors use 6 ft of concrete to shield against neutrons. There's higher energy particles than neutrons in space. I'm sure that external shielding plays a large role in it, but there's probably more to it. The wikipedia article on radiation hardening is actually very good. http://en.wikipedia.org/w/index.php?title=Radiation_hardening&oldid=235697687
...when you think Hubble is an astronomer.
I read the headline and thought there were complications during poor Edwin's double knee replacement.
at 10,000 a pound to launch the shuttle, weight reduction is most important. sending up lead computer cases because hardening a processor is hard is not an option when plastic weighs several pounds less.
Also up until 3-4 years ago the hubble was going to be shut down in the next year or two and was only extended later. Unlike the mars rovers the hubble's life won't magical extend.
i thought once I was found, but it was only a dream.
in such a small space by a good programmer. Most systems today are so encumbered by having been built by toolkits built on toolkits built on metalanguages ad nauseum that a simple "hello world" program now can run hundreds of K of memory.
My compliments to the programmers who still know how to get the most out of the little resources they're working with on these scientific probes.
Why bother with heavy shielding when you can just make the transistors big enough to not be flippable by single stray particals? Thick shielding might prevent 99.999% of dangerous bit flipping radiation from getting through, but what about that last tiny bit, you're going to need extra circuitry to detect errors in the processors circuitry... and everything starts getting more complicated, and you end up back where you started. In space, simpler is better.
The revolution will not be televised... but it will have a page on Wikipedia
A quote from the famous "Real programmers don't use Pascal" article written in 1983. Some of the most awesome Real Programmers of all work at the Jet Propulsion Laboratory in California. Many of them know the entire operating system of the Pioneer and Voyager spacecraft by heart. With a combination of large ground-based Fortran programs and small spacecraft-based assembly language programs, they are able to do incredible feats of navigation and improvisation-- hitting ten-kilometer wide windows at Saturn after six years in space, repairing or bypassing damaged sensor platforms, radios, and batteries. Allegedly, one Real Programmer managed to tuck a pattern matching program into a few hundred bytes of unused memory in a Voyager spacecraft that searched for, located, and photographed a new moon of Jupiter. The current plan for the Galileo spacecraft is to use a gravity assist trajectory past Mars on the way to Jupiter. This trajectory passes within 80 +/- 3 kilometers of the surface of Mars. Nobody is going to trust a Pascal program (or Pascal programmer) for navigation to these tolerances. If you have never read it, it's still a great read (at least for us old-timers). http://www.pbm.com/~lindahl/real.programmers.html
I love the end of the article:
"It's really reliable," she said. "There really is no need to upgrade it."
I wish more people understood that.
Actually, some sorts of shielding make things worse. Moderate amounts of shielding just end up providing targets for the really high energy particles, which releases a big cloud of moderate energy particles on impact. The secondary radiation is both more abundant and more likely to interact with the stuff on the inside, and so causes a bigger problem. For space applications, there are intermediate amounts of shielding that will actually *increase* the total dose. (This is the case for cosmic rays, not solar flares; the latter can be fairly effectively shielded against, but is frequently less of a concern.) If you're not willing to put *large* amounts of mass around the thing to be shielded, it's often impossible to improve things all that much.
Hardening often consists of simple changes that are nonetheless expensive because they involve changes to the whole production line -- things like rating all the transistors for a noticeably higher voltage, to reduce the likelihood of a radiation-induced latchup event. As chip voltages get lower, this gets harder. Other changes include things like using isotopically pure boron in your dopants -- boron comes in two common isotopes, 10B and 11B. 11B is relatively immune to cosmic radiation, but 10B will fision when hit -- releasing secondary ionizing particles that cause a much greater problem than the cosmic ray by itself would. So rad-hard chips end up made with (expensive) depleted boron.
Combine these, and you see why it's difficult to find a decent selection of rad-hard chips, and also why an up-to-date radiation hardened CPU can cost over $100k each -- and also why you nonetheless need them, and can't really substitute anything short of a few tons of shielding.
What you want may well be impossible. There are no magical materials right now to do what you want. Cosmic rays in the range TeV can't be stopped with a box that can be affordably launched, much less fit into the satellite. It's easier to use chips that are designed to handle them.
NASA already has a backup computer, on which are two independent circuits to do the same thing. Side "B" that is on the Hubble right now is handling things right now, after side "A" quit working.
NASA is putting the last of their spare parts on the Hubble right now, after which, there are no more short of restarting production, which isn't going to happen affordably. They made a lot of replacement parts which were gradually used as there were servicing missions.
Why *should* it be upgraded? I don't bother upgrading the microprocessor in my thermostat, it seems to work fine.
This is a bullshit article. Unfortunately, that has become the norm for Popular Mechanics.
The Intel 486 is hardly some arcane CPU that's so old that nobody knows how to program it. Anybody who can write assembly for modern PCs can write assembly for the 486. And anybody who wants to write in a higher-level language can -- because all the 486 development tools are still easily available.
If you read the article, you'll find that it presents no evidence whatsoever for its assertion that the Hubble's use of a 486 makes it harder to repair. In fact, it reads more like, "The Hubble has a 486, and damn that seems outdated to me! Maybe that's why it's so hard to fix!" Really, that's about the level of the 'logical' argument that you'll find in the article.
486 was officially the only space-rated hardware for a very long time. The problem is that when you create a smaller transistor, it becomes far more sensitive to ionizing radiation... the older the die, the larger - and thus less likely to be effected by radiation. More "modern" processors require more shielding.
meh
"PNG is somewhat better than TIFF last time I checked"
Most people learn at quite a young age that the word 'better' doesn't really mean anything on its own. Better at what? Better at supporting non-RGB colour spaces? Better at supporting RGB with more than 8bits per colour, or even floating point values? Storing multiple images in a single file? No, png supportings none of these things that tiff does. If you're creating computer graphics for UI's, websites etc, png is probably a better choice, as that's more what it's designed for, but there are many other uses for storing images outside of this scope that tiff fits much better than png. As far as compression's concerned, PNG supports DEFLATE, which existed before PNG did, and the same with TIFF and its supported LZW compression (not that there's anything stopping you compressing either with either).
To sum up: better at what?
The revolution will not be televised... but it will have a page on Wikipedia
Can't they just remodulate the shield harmonics or reverse the polarity of the neutron flow or something?
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
One of the reasons particles like neutrons are hard to stop is that they have no charge and don't react with the electromagnetic fields that bind matter together. You basically need a collision between the neutron and an atomic nucleus to stop it.
A particle that doesn't interact electromagnetically, however, is (if I'm not mistaken) less likely to interfere with electronic equipment. Which is not to say hard-to-stop radiation like neutron radiation does no damage at all, but I'd be curious to know whether it's a concern at all for satellites.
He who lights his taper at mine, receives light without darkening me.
It's common knowledge 486s (and their variants) were pulled from the classified wreckage at Roswell NM earlier last century. Trust me, they've had plenty of time to work with those babies.
Glad I could help clarify that.
-- Posted from my parent's basement
Good God man, if we do that, we could turn all matter into doesn't matter, then nobody will give a fuck.
it is only after a long journey that you know the strength of the horse.