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Hack in Space
MelloDawg writes: "From the press release: NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) spacecraft, which some had given up for dead in December after critical guidance components failed, was returned to full operations when the team developed an innovative new guidance system. The system uses a complex new set of procedures that lets controllers use electromagnets in the satellite to push and pull on the Earth's magnetic field. Details of the mission are online."
interstellar duct tape
It's things like this that really make me proud of our space program. Sure, it's a little tiny thing, we now have one less dead satellite, but that was a beautiful solution, and it's good to know that these folks are still there thinking stuff up.
If all the world's a stage, anyone who says they want better lighting spends far too much time in a dark theatre.
It works like a deep space compass :-O
Pretty clever hack. Every time I read about real scientists pulling off neat things like this, I get more and more disgusted with people who simply reboot a server whenever it hangs because it's easier than actually thinking about what the problem is and how to fix it.
Some people have a way with words, and some people, um, thingy.
how much morons would have taken it this time to figure that one out? ;-) as much as they needed to screw in their new light-bulb at the mess-hall?
seems they discovered to make all those refrig magnets they send out there have some use after all!
Live, let _them_ die
made me proud of fellow lumberjacks. Imagine, hacking trees where no trees exist (sort of like BC, after clearcutting). Afterall, that is what all we Canaduhians think aboot, right :)
I admit, it's an excellent hack.
But on the other hand, it's hard to forget what NASA has been doing for the past few years. Failures and mishaps. Bugs in software. Human errors. In critical projects, in times when funding is already really hard to get.
Luckily this time, the engineers had the means and actually got something fixed - but most of the recent news have been pretty much from the opposite end of the happiness scale. Too bad this wasn't a Mars probe - it would've had a tremendous PR value for the whole Mars exploration concept.
__
Zarathustra.fi
Modern man has no goal, no aim, no ideals.
I just had to say that. I think I'm going to go rent October Sky now (if you haven't seen it, you need to. It's guaranteed to make any true geek cry).
-Adam
aye, 't is true. instead of viewing NASA as space pioneer demi- gods, i think more of them as managers lately. no more ground breaking projects, but a lot of meeting. they should be planning to go to mars. we should spread the human race to avoid extinction in the long run. to explore strange new worlds, to boldly go .... ok that was a bit over the top, but do you remember when they lost a sattelite because 1 department use psi for its calculations, and the other Nm^2?
we'll never build an enterprise like that.
here I am sitting 2 am in the morning trying to fix my printer for last 4 hours... :/ :/
here i am posting on slashdot, just remembering unplugging the printer before I took it apart and not pluggging it back in...
fuck it, i'm off to a bar. THANKS NASA! first you ruin my dreams of being an astronaut (at 6'5" I am too tall) and now you rob me of my manhood... or geekness... call it either way.
Did they keep the ICBMs secret this time, or did it go haywire and start targetting the US again? Someone call Clint Eastwood and tell him to pack an overnight bag.
Then I realized my foodstamps are worth more.
Writers imply. Readers infer.
Everyone seems to think that since many of the outward looking missions are having trouble that NASA isn't really doing much, check out all the reasearch thats being done on our actual planet. NASA has been collecting huge amounts information about Earth's atmosphere, oceans and land, and they've been doing important analyses. I'd suggest you check out places like:
earth.nasa.gov
earthobservatory.nasa.gov
terra.nasa.gov
data assimilation office
and for image products:
visibleearth.nasa.gov
NASA does alot of interesting earth science too!
Hope they register within 30 days.
... did they say it blew a FUSE?
here I am sitting 2 am in the morning
As opposed to 2 am in the afternoon?
A basic problem in satellite stabilization is how to get rid of unwanted angular momentum. There are a few options.
You can throw away something. Usually this is reaction mass from a small rocket, or just compressed gas. Weights on the ends of cables that unwind and break free have been used to despin satellites.
You can store angular momentum in an inertia wheel, which is a flywheel on a motor. This doesn't get rid of angular momentum; it just stores it as long as you keep the wheel spinning. Eventually, you hit the maximum motor speed and can't do anything more in that axis. So it's also necessary to have some way to drain off angular momentum, even if very slowly.
You can couple to a gravity gradient. This is done with a long pole aimed towards a nearby planet. The difference between the gravity at the ends of the pole is tiny, but enough that if you get the thing pointed down and stable, it usually stays that way. Only good for one axis, of course.
You can couple to a planetary magnetic field, like these guys are doing. Again, only good for one axis, but it's a different one than the gravity gradient. It's a weak effect, but stronger than the gravity gradient.
You can put out sails and get reaction forces from solar energy. This gets talked about a lot, but isn't done much.
All of these are known techniques. It sounds like this satellite had four inertia wheels and an electromagnet for torquing against a planetary magnetic field. The plan was presumably to maneuver with the inertia wheels, and slowly drain off unwanted angular momentum with the magnetic torquer.
With two inertia wheels down, there are still three torquing devices available, so control of orientation is theoretically possible. Tough, but possible. It's impressive that they made it work.
Using the Earth magnetic field is something used in Amateur radio satellites since many years.
What did one magnet say to the other magnet?
I find you very attractive.
First off bravo to the NASA geeks. I always find it truly heartening when they pull these last minute hacks off. They don't really need to. I hadn't even heard about this one breaking, it wasn't that much of a PR problem. I think the only reason they really bothered is because, like any good geeks, this is their toy, and they love it too much not to try.
Second, to people bemoaning the absense of mars missions and moon bases. Why go? Can we learn so much more by sending people that it justifies the risk and cost of doing so? These are the questions being asked. And if you think this means our motives for going to space aren't pure, think about this: would we have gone to the moon had the Russians not been trying to beat us there?
I think the best way to get American astronauts on Mars today would be to convince Bin Ladin to start a space program.
I for one wonder if NASA has perhaps outlived its usefulness. Could it perhaps persist as a regulatory body, overseeing commercial space ventures, and allowing all-to-scarce public research money to go to other areas?
The mission to Mars sounds even less appealing once you consider how much cancer / AIDS / environmental / fusion / fuel cell / quantum computing / immortality / (name your favorite project) research it would replace.
Obviously the answer is more funding for public research, but then, does anyone really see that happening?
In Capitalist America, bank robs you!
Yes, that's all very well and good, but that is on earth. NASA is called the National Aeronautics and Space Administration for a reason.
NASA used to do stuff like send men to orbit or the moon and test new innovative aircraft. Now they send people up in the space shuttle, and drop them back down. I wish they'd do something interesting again like colonize the moon or something.
--Metrollica
Some people objected to installing a potent soundsystem in a satellite, but the subwoofer saved the day.
In space, noone can hear you scream.
The channel Homer happened to flick to shows two men talking about the
impending launch of the space shuttle.
Tom: It's a lovely day for a launch, here, live at Cape Canaveral, at
the lower end of the Florida Peninsula, and the purpose of
today's mission is truly, really electrifying.
Man 2: That's correct, Tom. The lion's share of this flight will be
devoted to the study of the effects of weightlessness on tiny
screws.
Tom: Unbelievable, and just imagine the logistics of weightlessness.
And of course, this could have literally millions of applications
here on Earth -- everything from watchmaking to watch repair.
Homer: Boring.
[tries to switch channels, but the batteries fall from the
remote control]
No! The batteries!
Tom: Now let's look at the crew a little.
Man 2: They're a colorful bunch. They've been dubbed "the Three
Musketeers". Heh heh heh --
Tom: And we laugh legitimately. There's a mathematician, a different
_kind_ of mathematician, and a statistician.
Homer: Make it stop! [panics]
Bart: Oh no, not another boring space launch. Change the channel.
Change the channel!
Homer: I can't! I can't!
[Bart dives for the plug and tears it from the wall]
[He and Homer both sigh]
--Metrollica
What good are these things without duct tape?
NASA isnt bad... its just identical to the real corporate world, which btw also sucks.
One solution: let the engineers RULE a little more and actualy have 50% control in all decisions, not 100% by management.
You can couple to a planetary magnetic field, like these guys are doing. Again, only good for one axis
Not really. Full 3-axis stabilization can be implemented using the Earth's magnetic field. Unlike a passive pole the magnetotorquers are active elements and the magnetic field doesn't always point down so at different parts of an orbit it can be used to control all 3 axes.
Design and Experimental Test of Magnetic-Torquer-Based 3-Axis Satellite Attitude Controllers
Stop worrying about the risks of nuclear power and start worrying about the risks of not using nuclear power.
So, reversing the polarity really DOES work!
Arrrgh! Bill is everywhere!
Conversion Rate Optimisation French / English consultant
This automatically put the satellite into a pre-programmed "safe mode" configuration on December 10, 2001.
Don't tell me it's running Windows!
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This type of smart-ass remark is EXACTLY why I still read slashdot after all these years.
Thanks for the laugh.
What the article omits is that the fine pointing accuracy is achieved using the magneto-torquers in combination with the two still operational reaction wheels. From the original NASA press release (dated 14 Dec 01) where the anomalies with the two reaction wheels were reported the strategy was laid out to rescue the science mission:
One of the new control mode concepts being investigated is to use the two operational reaction wheels in conjunction with the satellite's magnetic torquer bars to provide control in all three axes. The magnetic torquer bars are presently used to manage the momentum of the reaction wheels by applying a torque on the satellite against the Earth's magnetic field. The torques necessary to make up for the failed wheel would be in addition to that required for momentum management. This is well within the capability of the magnetic torquer bars.
What they probably managed to do is to use the two remaining wheels to do the fine pointing but the satellite will tend to slowly spin 'of course' lacking the two other wheels to compensate. By bringing the torquers into the loop they cancel the spin and attain the fine pointing.
It is nowhere mentioned but I wonder if they can maintain the pointing accuracy long enough to get maximum exposure time. Since they've said that the spacecraft has been restored to full operations I guess it is not a problem.
I'm not trying to take anything away of what they achieved, only to clarify what is omitted from the article (possibly not to make it too technical I guess). It still is an impressive feat and indeed a super hack!
something wicked this way comes...
Sorry, the Preview screwed up the URL. Here is the link to the original NASA Press Release.
something wicked this way comes...
Considering this week's poll... Possibly a better header would have just been "Geeks in Space not totally gone..."
Sorry. It's 4 in the morning and I'm all out of American Dew...
Karma: Non-Heinous
It's been done for years! 25 years ago, I worked for the Defense Meterological Satellite Program. In 1976, we used the same technique to rescue a (brand new) spinning satellite and lock it back into an Earth-facing orientation.
ALways amazes me how some americans are bad mouthing their own space program. NASA is pretty much one of a kind and a a european I can only watch in awe (and a little bit of envy) on some of the stuff NASA pulls of, like this one.
Whenever someone tells you americans about how moronically stupid you are you should show them stuff like this and tell them to show what clever stuff they done lately or sod off...
Yes, hopefully ESA will get up there as well, but for the moment we're behind IMHO
if (!signature) { throw std::runtime_error("No sig!"); }
It's hard to imagine where we'd be today if it weren't for the great minds at NASA. So many innovations have come out of NASA. Truly a great set of minds. It really sucks that so many people want to cut their budget.
scott
What Nasa needs is another cold war. Something that doesn't have any waste with destruction, just lots of money going into research.
I almost went to work on this satellite when I was picking grad schools. FUSE is run at Johns Hopkins University. I think it is the only satellite that is run by an American University. The control room and all is in the basement of the physics building...
The system uses a complex new set of procedures...
A NASA Ultraviolet Spectroscopic Satellite uses complex procedures for guidance. What ever happened to controling a satellite with smoke signals?
-... ---
Well, I must say it looks as with budget cuts and a total lack of inspiration (possibly a result of the cuts) NASA is starting to lokk more and more like its russian counterpart, aging technologies, equipment poorly designed equiptment, and having to hack everything to hell and back just to get it to work.
Maybe I should go into the space-tape buiness, or selling external aftermarket thrusters to keep this shit in space.
I am really suprised NASA is in as bad a shape as it is, The Military can use space as the ultimate high ground, cmon the AF even has space figter training in progress, where are the damm ships and when will these efforts pay off in the comercial sector ?
The moon missions were singulary one of the greatest technical feats ever accomplished, more research and commercial products were born from the Appolo missions thatn any other goverment venture sending us YEARS ahead of our competiton , only for what ? To sit on our asses and never rise above 30 year old shuttle designs ?
Sig went tro...aahemmm.....fishing........
I have no idea what you are talking about. I seem to remember NASA launching a lot of new technology into space. Just because NASA doesnt send men to other heavenly bodies, doesnt mean they are useless. The asteroid exploration satellites were big. Hell, they even landed the damn satellite on the asteroid, even though that wasnt the purpose of the device. Although, that was just NASA playing around. They keep sending exploration devices to mars. Give them time. Its not like it is the late 60's and they have full support and funding from the president himself.
How long will it take to those who did it be persecuted by the DMCA? Seems like they have been circunventing something...
"Emancipate yourself from mental slavery, none but ourselves can free our minds !"
About five years ago, Hughes launched a communication satellite. To be useful, these have to reach a geosynchronous orbit. It turns out that the most efficient way to get to from a low-earth orbit to a geosynchronous orbit is to fire a rocket twice [or so it was thought.] The first firing raises the apogee of the orbit to the geosynchronous altitude; so that the satellite is in a very elliptical orbit. Then, when the satellite is at apogee, you fire the rocket again to circularize the orbit. Usually this same motor changes the plane of the orbit as well. Most satellites are launched into orbits inclined to the equator somewhat, and geosynchronous satellites have to be over the equator. It is most efficient to make the orbital plane change at apogee, too.
There was a rash of apogee kick motor failures, and in this particular satellite the motor failed, leaving the satellite in a uselessly ellipitical orbit. There were small thrusters on the satellite which were to be used for station-keeping (small orbital adjustments) but it didn't have nearly enough propellant to raise the perigee. Hughes finally abandoned the satellite.
But one engineer refused to give up. It turns out that the transfer orbit paradigm above is the probably most efficient path in a single-planet system, but Earth has this anomolously large, close, Moon. And while there wasn't nearly enough fuel to get raise the perigee to geosynchronous altitude, there was more than enough fuel to raise the apogee out to lunar orbit. He was given permission to try to rescue the satellite.
In the end, two passes by the moon were made, each raising the perigee somewhat and lowering the inclination of the orbit. The remaining fuel in the satellite was used to lower the apogee back to the geosynchronous orbit altitude, but unfortunately the inclination couldn't be brought down quite to zero, so the satellite isn't in its desired orbit even today. Still, it's in an orbit where some use can be derived from it.
The satisfying conclusion to this story would be that all geosynchronous satellites are launched this way, now. Unfortunately, you can't mess with the status quo to that extent; and satellites are still, in the main, launched the old transfer-orbit way.
thad
I love Mondays. On a Monday, anything is possible.
This property only works in low earth orbit because the strength of Earth's magnetic field is not significant in higher orbits (such as Geo, Heo, and so called "Deep Space")
...in this day and age, I wouldn't be surprised if they get a cease-and-desist order in the mail in the next few days because they're infringing on someone's patent or violating someone's intellectual property.
But hey, that's the screwy stated of intellectual property and patent law these days.
Ed R.Zahurak
You know, oblivion keeps looking better every day.
> Grammar nazis unite!
Should that not be "Grammar Nazis unite!" instead?
Virg
There was some work done in an attempt to replace fuses on spacefaring vessels with breakers, the idea of course being that if a breaker popped, a servo could reclose it at a later time (we looked into this issue while I was in college, putting a not-small amount of work into materials development for low-temp breakers that would still work). The concept was scrapped, however, when NASA engineers who were getting our results discovered that (at least with late '80s tech) repairing the fault that opened the breaker was more often than not impossible by remote, so having a servobreaker was pointless. Still, with advances in robotics, I'm still hopeful that one of these gizmos will become useful, and having my name engraved on a piece of polymer that gets to leave the solar system would be a nice memorial.
Virg
Ok then... I'll give you some code for a high fidelity magnetic field model and an orbit propagator. If I just tell you the dipole moments of the three torquer bars and the spacecraft's inertia tensor, you should be able to come up with a simple control algorithm in fairly short order. By the way, we can't accept any more than 1/4000 degree in attitude jitter. Oh yes, your solution has to run on a 386 and not crash for the next 3 years or more, by the way. :b
Kidding of course!
Didn't the scientists actually get the satellite up and running as fast as possible? What would you have had them do, get a really long stick and push it?
The problem is not that you need to push the big button in the sky sometimes. The problem is developing a mentality that says that rebooting the server "fixes" the problem. Rebooting the server is palliative. It keeps people from taking preventative and prophylactic measures. This attitude and its destructiveness are lamentably common in business.
We need to go because the alternative is suicide. We need to go because we are human and wish to continue to be human.
The most valuable result of the moon landing was not the scientific research, the spin-offs, or the political gain. It was the photograph of Earth as seen from the moon, just after Earthrise, taken by a human being, holding the camera.
To continue to have frontiers is more important than anything else. We could cure cancer and AIDS, fix the environment, and become immortal, and we would be nothing more than healthy, immortal apes. But the way of the explorers is a way that apes do not know, and we must keep it. At this juncture, that means deep sea exploration and space exploration, in person, not by robots.
Or perhaps they'd have beamed it into the cargo bay and fixed the damn wheels.
Think, people, think!
Virg
1) Lean how to spell "communist".
2) Communism is OVER. Learn to live with it.
3) No oil, no food at the supermarket. No food at the supermarket, my kid starves. That's worth fighting for, I'd say. Hell, I'll even fight for my hotrod.
4) Go learn some physics and chemistry before spouting off about solar power and electric cars, please. These technologies are not ready to replace oil, and you would know that if you had clue #1 about how things work.
5) We are not fighting for oil right now. We are fighting evil, cocksucking, goat fucking Arabs who want us all dead. Their reason for wanting us all dead is religious, not because we fucked them over. Go visit New York and see the hole they made before continuing this outgassing of idiot leftist vapour you seem to be bent on.
6) In case all of the above is wasted on you, try this experiment: Go to any Arab or Communist country and publicly protest the local government. Compare the experience with your protests here in the civilized world. If you live, report on your results to Slashdot, we will all be fascinated with your findings.
6) Your rhyme is terrible. Work on it.
</i> NASA are a bunch of nerds </i>