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Hubble Verdict: De-Orbit
theonetruekeebler writes "CNN reports that NASA has reached a final decision for the Hubble space telescope: De-orbit. At some future date a liquid-fueled rocket will dock with the telescope and fire, hurling Hubble into the ocean. However, "Our best estimate is we probably will be able to continue to do science as we're doing it ... somewhere into 2008," according to program executive Mark Borkowski."
Hubble is meant to run mainly off solar power. Shooting it out of the solar system would make it useless after it got a short distance from the sun. Its communication system is not made to broadcast very far, and giving it a high velocity would drastically decrease its ability to take clear pictures. Also, it isn't really made for "extra-terrestrial contact". It doesn't have any greeting plaque, just some dirty pictures written on it by astronauts and the various labels and warnings on the parts.
It's in orbit currently. It would take alot of energy to actually get it to escape the earth's gravity. Much more to get it to any speed where it won't be overtaken quickly by other space probes that are *meant* to go out there.
"You know, Hobbes, some days even my lucky rocketship underpants don't help" -- Calvin
Fact is its not better anymore. At least in the visible range the VLTI is better.
But of course there is no alternative to a space based telescopy in the UV and IR (which is now done by the pfitser), but the main problem is that keeping it up there isnt the problem, but the fact that its getting OLD. Nearly everything needs an overhaul.
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
It's not just getting old, it's getting BROKE. After about 2008, it's going to be useless. It won't be able to aim at anything because of the failing gyroscopes. We don't want that in orbit for even longer, we want it de-orbited.
Fascism trolls keeping me up every night. When I starts a preachin', he HITS ME WITH HIS REICH!
Because it's not about its orbit, but about its targetting system. It has these gyros to prevent it from rotating (or to make it rotate), and they're breaking down. It needs 2 to work, and it has 3 now.
NASA believes they can keep one in reserve and that way keep it working until 2008, but either a repair or scuttle mission has to be mounted before then.
Believe it or not, there is some friction up there in orbit, even though we describe it as "hard vacuum." There's not much, granted, but there's enough drag that it will eventually pull the Hubble (and anything else in orbit) down into the thicker atmosphere. Most all satellites have some thrusters/rockets built in to them to allow them to self-correct their orbits...but, those require fuel...once the satellite's out of fuel, it's coming down...the only question is where.
Actually this is a very common misconception.
Any satellite in a stable orbit is in freefall and expending none of its own energy to stay in that state. To change orbits, either up OR down requires a change in velocity, and that change in velocity requires fuel. So up is just as difficult as down energy wise.
The only free ride you get in the down direction is when you get low enough so that atmospheric drag begins to slow you down.
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
Co-incident with this is the Columbia Investigation Board recommendations which recommended several extensive improvements, and which recommend that until those are finished around 2010, that only two Shuttle flights be allowed.
Given that at least one of those two flights would have to be dedicated to retrieving the Hubble, it doesn't seem worth it, compared to, for instance, keeping the Space Station going or otherwise doing real science.
Much as I admire the effort behind the Hubble project, Hubble is dead. It is gone. And for the cost of keeping it going another 4 years, you could design, build and launch another, lighter, more modern telescope.
It's like trying to run Doom 3 on the latest Alienware retrofitted with a 486, no matter how much you bolt on it still will fail. Sometimes you just need to dump the older bits and upgrade the whole kit. Hell, send up a fleet of new ones and put them at Lagrange points.
How many people can read hex if only you and dead people can read hex?
Cost of a Space shuttle: $700,000,000 per launch (not counting the latest $2,000,000,000 in upgrades or the initial cost)
22 tons http://www.braeunig.us/space/specs/shuttle.htm
Even taking into account inflation, the Saturn 5 still looks better.
Purely science fiction?
The Russians built and launched one (which failed due to technical problems). The concept is certainly within our reach.
Also, solar sails would work in low earth orbit. Photons of light impart force, not just the solar wind. That's how (as another example) those laser propelled spacecraft ideas would work, as well.
Umm... now for a clue. The next scope has already been justified. It is the James Webb Telescope. It is huge and will be orbited around the Earth-Moon L2 point. The last schedule I saw had it launching in 2010 (But I hope someone can provide more recent info). The Hubble has been wonderful. Its replacement is on the way. We can live with a 2 or 3 year gap. The universe will wait. ... And NASA needs the money for other stuff. Now if we could only get Babs Mikulski (Senator from Md) to stop forcing NASA to spend its money where she wants it, maybe we can do a few other amazing/needed things with NASA funding.
-- Instant Karma's gonna get you! [320848 = 2*2*2*2*11*1823]
Oh, I should have put this link into my first reply. JWST is scheduled for launch in 2011.
-- Instant Karma's gonna get you! [320848 = 2*2*2*2*11*1823]
Yes, but not enough. He has stated he wants to go to the moon again, and on to mars. Which is I agree with, except that he hasn't raised funding enough to do so, and still save an extremely important research tool long enough to keep it online untill its replacement is launched (assuming no delays, in 2011).
The problem is that Hubble is already low enough that atmospheric drag slows it down. It already expends fuel on a regular basis to update its orbit. IN fact, there isn't a need to fire the engines to bring Hubble back in. It will come down on its own eventually. The reason to save some fuel and bring it down on its own power is for timing...so that it does land in the ocean and not a highly populated area, just in case it doesn't all burn up in the atmosphere. Also, this applies to low earth orbit. Those geosynchronous satellites are far enough out there that from an energy view its easier to break from orbit "up" (escape Earth into solar orbit) than to come back to Earth
Not only that, solar photons impart about an order of magnitude more force on a solar sail than the solar wind. In fact, solar sails are propelled by solar photons. The solar wind has a negligible effect (confusion arises because people seem to assoociate "sail" with "wind"). So the lack of solar wind in LEO would make no difference at all. What might make a difference is the massive area-to-mass ratio of the solar sail, and the correspondingly high atmospheric drag that would cause a LEO solar sail to deorbit fairly rapidly.
Everything you said is correct except Hubble has no engines to fire - it has no thrusters. It depends on boosts from the Shuttle to keep it from deorbiting just like the space station does.
Hubble is so high up that it would take years for atmospheric drag to cause a de-orbit. To cause a controlled de-orbit means flying up and attaching a thruster. Since they had (still have) to do this anyway, trying to repair it wasn't that much more expensive.
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
The main advantage of space for a telescope was avoiding atmospheric distortion. Now it is possible to adjust the mirrors to compensate for atmospheric distortion (adapive optics), enabling large and clear telescopes on the ground (Earth). Here's an explanation of how a guide star is used to "eliminate twinkling". In short, orbital telescopes may be obsolete once these technologies are perfected.
to err is human, to forgive is divine, to forget is... umm...
- Read my other posts - moving it to somewhere else in the solar system outside the immediate area of the earth-moon orbit is not the same as moving it outside the solar system
...
- Escape velocity from the solar system is only 41 km/sec, less than 4x the earth's escape velocity.http://www.answers.com/topic/escape-velo
c ity
Light speed is about 300,000 km/sec, so even at 41 km/sec, you're still doing about 0.00014 c. Not much doppler shift there, is there?Why not just do nothing and leave it up there?
It's falling out of orbit (slowly) and there's a 1 in 700 chance it'll hit people when it lands. They want to bring it down into an ocean under control.
It only has enough battery and gyroscope life left to be useful for another couple years without service so at that point it's just a danger and they've deemed it too risky to fix.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
That's right. Which means that all those gorgeous images the previous poster was talking about will no longer be available other than with false color.
Why they can't put a visible light CCD on the JWT is beyond me, but whatever. Not to mention the fact that the JWT will be impossible to service at a LaGrange point.
+++ATH0
Actually, the James Webb Telescope will orbit the Sun-Earth L2 point.
The difference between Hubble and ISS is the inclination (angle towards the equator, roughly), not the height.
What keeps me going is my inertia.
False colorization is very common in astronomical images released for public consumption.
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana