[Retsof]

So, you are probably all aware that Hubble will eventually be scrapped, and will be instructed to incinerate itself in the atmosphere.  Now, if I recall correctly, part of this is to make room for the other orbital telescope that they're planning on launching.  Now, why not have both up there?  Also, I am aware that Hubble will eventually be more trouble to repair than its worth, but why send it down?  I would find it much more fitting to send it out into the stars that it gazed upon for so long.  Mabe I'm just overly sentimental, but dosen't that make some sense?

[The E]

Sending it out into space would require a Shuttle mission to go up there and install some add-on thrusters powerful enough to lift Hubble out of orbit.
As nice as that would be, it's just not cost effective to waste one of the few remaining Shuttle flights on something like that.

[Retsof]

So it dosen't have enough juice to even get a gravity slingshot to work?

[Galemp]

I wish they could bring it back and put it in the Smithsonian.

[Retsof]

That was one of my other thoughts.

[Akalabeth Angel]

Aren't two telescopes better than one?

[General Battuta]

So it dosen't have enough juice to even get a gravity slingshot to work?

...

Okay, misunderstanding orbital mechanics here. For a gravity slingshot to work, you need to start way outside the gravity well. You don't have much gravitational potential energy right down in orbit.

[StarSlayer]

So it dosen't have enough juice to even get a gravity slingshot to work?

...

Okay, misunderstanding orbital mechanics here. For a gravity slingshot to work, you need to start way outside the gravity well. You don't have much gravitational potential energy right down in orbit.

Yeah like in the Farscape pilot episode (well the one at the end not the first one)

"E = MC Hammer"

[Nuke]

hubble has far exceeded its potential. but from a maintenance standpoint its an old car waiting for the scrapheap. shes lived a good life, let her die a fiery death and make room for a better model (one that has a better cpu than the 486).

[Retsof]

So it dosen't have enough juice to even get a gravity slingshot to work?

...

Okay, misunderstanding orbital mechanics here. For a gravity slingshot to work, you need to start way outside the gravity well. You don't have much gravitational potential energy right down in orbit.

Well, I kinda meant something more along the lines of a little push that eventually builds into escape velocity.  Is that possible?

[General Battuta]

So it dosen't have enough juice to even get a gravity slingshot to work?

...

Okay, misunderstanding orbital mechanics here. For a gravity slingshot to work, you need to start way outside the gravity well. You don't have much gravitational potential energy right down in orbit.

Well, I kinda meant something more along the lines of a little push that eventually builds into escape velocity.  Is that possible?

If you had a big push you could manage a slingshot from close in, but the whole point of a gravity slingshot is that the planet pulls you in, closer and closer, but you just manage to miss it and the added velocity (plus some thrust) lets you hurtle off in the direction you want to go.

[Tomo]

So it dosen't have enough juice to even get a gravity slingshot to work?

Okay, misunderstanding orbital mechanics here. For a gravity slingshot to work, you need to start way outside the gravity well. You don't have much gravitational potential energy right down in orbit.

Well, I kinda meant something more along the lines of a little push that eventually builds into escape velocity.  Is that possible?

Afraid not - There are solutions to multiple-body-problems that steal momentum from the other bodies giving one of them escape velocity, but we don't have the measurement and simulation capability to predict these accurately enough. This is a very chaotic system, so undetectable errors in current velocity and position of the bodies result in drastic changes to the outcome - thus we could 'try', but end up sending it straight through the ISS a couple of years later.

Gravitational slingshot manoeuvres work by 'dumping' mass - you take a lot of mass down the gravity well and leave it there, stealing the momentum of the discarded mass to get out of the well yourself.
To date we've normally done this by burning lots of fuel at the bottom of the pass, and Hubble doesn't have much fuel left.

[Retsof]

Yeah, I guess you're right, the slow build up might work, but there's too much risk of hitting something.

[Kosh]

I wish they could bring it back and put it in the Smithsonian.

With what? The shuttle is the only thing capable of bringing it back, and that will be in the smithsonian very soon.

[Galemp]

That's why I said 'could' and not 'would.'

[Mongoose]

A small part of me dreams of someone rigging up a custom re-entry craft for Hubble that could be launched on the (hopefully) upcoming Ares V rocket, rendezvous with Hubble in orbit, automatically encapsulate it, and then safely return it to Earth.  That small part has no foundation whatsoever in practical reality, but it's nice to dream.

[Goober5000]

So it dosen't have enough juice to even get a gravity slingshot to work?

To date we've normally done this by burning lots of fuel at the bottom of the pass, and Hubble doesn't have much fuel left.

Hubble has no rockets or fuel at all.  It doesn't need any*.  The only way it'll change its orbit is if something comes up and gives it a shove.  That's why they installed a docking mechanism on the most recent flight.

*Not even for pointing.  It uses gyroscopes for that.

I wish they could bring it back and put it in the Smithsonian.

They had plans to do just that, on STS-144, originally scheduled for (ironically) November 2009.

I sorta agree with how it panned out though; if you're going to go to all the trouble to send a shuttle up there anyway, you might as well do a servicing mission.

[Mika]

Hubble telescope would be interesting to see in museum. By the way, how many of you are aware how large that thing is? It weighs about 11 tons, and is about a size of a bus.

It is fascinating to think how they have managed to pull that thing off from the manufacturing side. Wikipedia mentions that the form accuracy would be 10 nanometers within the area of three metres! It is even more impressive since the mirror is hyperbolical, and not spherical. Those accuracies should hold even after the thing has been put on orbit. In optical sense, the system is not very complicated, but from manufacturing side, those engineers must have had a lot of sleepless nights figuring out how the hell do we pull us out of this mess.

One always wonders would it have been better if the primary mirror would have been polished to a correct radius. The new space telescopes will continue the saga of imaging distant objects straight from the space and do so better than Hubble did.

[Tomo]

Hubble has no rockets or fuel at all.  It doesn't need any*.  The only way it'll change its orbit is if something comes up and gives it a shove.  That's why they installed a docking mechanism on the most recent flight.

Just checked, and you're absolutely right.
I thought it had a few small RCS to maintain orbit against the tiny bit of atmospheric and magnetic drag like the ISS uses, but it doesn't.

[Goober5000]

Hubble is in a lot higher orbit than the ISS, so the drag is much less.

In fact, they decided they didn't even need to reboost the telescope during the most recent mission, since the amount of time before it drifts low enough to be a problem is expected to be about two or three times its remaining lifetime.