Maybe the hubble could play a role being a practical projectile to hurl at an incoming asteroid. Whether the hubble is 1) a dead weight corpse or 2) still functioning in some capacity. Maybe NASA could build a booster rocket that could attach to (and or collect) the hubble and then intercept the asteroid. If the hubble is dead, then its still available mass that doesn’t need to be lifted into orbit. If the hubble is still functioning, maybe it could also be used in targeting the asteroid. I think we desperately need ANY options when considering how to stop an inbound asteroid. So I’m suggesting at decommission time, if possible, the hubble should be parked in the highest orbit possible instead of being sent back to earth. NASA could build this booster rocket and keep it on earth just waiting in case its needed.

Not much we can do about that. Besides, because of the correcting lens in the Hubble, aren’t some Earth based observatories doing the real cutting edge stuff to fill the time gap? Adaptive optics and all that.

Here’s a thought: could a constellation of Hubbles be used as an arry to observe a single target? Maybe at least for wide field?

2 are not working, two are in operational mode, and two are on standby. That means if one or both currently operational ones go down, the remaining (off) ones will be turned on.

The problem is that if they fail, Hubble becomes practically useless, and also probably impossible to dock with. And there’s that nagging problem of no way to perform a controlled deorbit.

That’s why the mission is somewhat urgent. You hate to be on your last string because there’s no margin.

Sorry, but the betting is on no rescue mission and more cancelled science missions.

Thanks. That’s why I keep coming to this site. I wind up learning more about subjects I thought I knew about. Cool.

- Jack

Bob Park has long pointed out that the repair missions cost more than actually making a new Hubble and launching it with an unmanned rocket and an unmanned rocket can place the telescope in a more science-friendly orbit:
http://www.bobpark.org/WN03/wn022803.html

Of course we immediately start making those new Hubbles it will be years before the first one will be ready for launch. It will also require NASA to admit error. Just think astronomers could have found with several Hubbles. But that would probably required planning to do it that way from the very start and getting the funding. It is probably easier to get funding for spectacular rescue missions than for making a new Hubble.

And now we are in a position that if they don’t do the rescue mission there will be a gap of years between Hubble’s death and the launch of the Next Generation Space Telescope that is not designed to last as long as Hubble has anyways and cannot be repaired from orbit. And I bet they are not seriously working on its replacement. It is like Ford making a truck, waiting a decade or two, and then considering what should come next. New space telescope, new space shuttle, new whatever: when one is launched the next one would be under serious development.

Make we should take some of the billions we sunk into Iraq and give it to NASA…

“…I presume you mean gyro platforms, not individual gyros. It takes three to make a platform to keep a vehicle 3-axis stable. If you’re down to two, then the vehicle is going to be pitching, rolling or yawing when you get there…”

No, mechanical gyros have 2 channels of rate sensing per gyro (they sense rates about the two axes perpendicular to the gyro’s spin axis). With 2 gyros (as long as their spin axes aren’t parallel!), you have single-channel data on two axes and two-channel data on one. If you only have 1 gyro, you need to get your third axis of rate data from some other sensor — for Hubble, likely the FGS (fine guidance sensor) star trackers.

Also, see my response to ioresult on why Hubble has spun-mass gyros. Hubble has dramatically higher pointing requirements than does an ICBM or SLBM.

Lorne

“…About the gyros: why don’t they use gyros without mobile parts…”

Because they have unsuitable drift rates. Mechanical gyros (while they can have lifetime issues) have much better fine-pointing performance. That’s why they’re used on all orbiting telescopes (at least, all the ones I know of). They’re on Hubble, Chandra, and Spitzer, as well as others…

Lorne

I presume you mean gyro platforms, not individual gyros. It takes three to make a platform to keep a vehicle 3-axis stable. If you’re down to two, then the vehicle is going to be pitching, rolling or yawing when you get there.

I agree with ioresult. It seems impossibly archaic to be using mechanical gyros at this point. Way back when I worked for Lockheed (just slightly after the earth cooled), we went to laser gyros on the Trident II in 1978.

- Jack

Honestly, if it takes a whole shuttle launch to upgrade/repair anyway, why not mass produce the basic space telescope framework (power, attitude control, communications), and launch a new one (with the current state of the art equipment plugged in) on a Big Dumb (cheap) Booster when one fails?

We can call them the Iridium Space Telescopes.

About the gyros: why don’t they use gyros without mobile parts, like a “Hemispherical Resonator Gyroscope” ( http://www.nsd.es.northropgrumman.com/Html/HRG/index.htm ), which they use on Cassini?

Or even a Fibre optic gyroscope ( http://en.wikipedia.org/wiki/Fibre_optic_gyroscope )? Or a Ring laser gyroscope ( http://en.wikipedia.org/wiki/Ring_laser_gyroscope )?

The ISS is a joke, scientifically speaking, and not a very good one. I say ditch it and give the money straight to the Russians (that’s what it’s for, anyway).

GAry 7

For me, Hubble is a milestone of human achievement. I think it should be repaired and kept in service as long as possible, and then preserved in orbit as a historical monument. A weird place to keep a monument, but still. Hubble is on the scale of the other historical places we preserve, like Independence Hall, the Old State House… and like Tranquility Base should be preserved, when we finally get back there.

For Lab Lemming,

NASA wants to finish the space station before retiring the shuttle. After that, then our missions to the moon will absorb the money.
While that may still cut into planetary exploration, at least we’ll be GOING somewhere now, rather than counting laps.
You can rest easy though; DAWN is approved. I think the Phoneix Mars lander is also good.

MESSENGER is in progress, as you know. So is New Horizons. Cassini is still going strong.

I don’t know of any other planetary missions. The one that got axed that I would’ve liked to have seen was the JIMO. Shame about that one.