First, welcome to the listeners from Coast to Coast AM! Update: If you listened to the show, you heard me get a little tongue-tied about when the last servicing mission was. It was in March 2002. 
It looks like we’re going to get a decision soon on whether or not NASA is going to service the Hubble Space Telescope. Here’s the deal: Hubble is designed to undergo periodic upgrades. Designers knew that technology would advance, and astronomical detectors would get better with time. So they built Hubble in a way that allowed astronauts to go there and pull out old stuff and out in the new. For example, there was one camera on board Hubble called STIS. It went up in 1997 to replace an older spectrograph. In all, there have been four servicing missions so far (NASA doesn’t like to call them repair missions, and honestly, they aren’t fixing it, they’re updating it).
But there’s more to it. There are gyroscopes on Hubble that keep it stable and locked on its targets. They’re similar to toy gyroscopes, but a lot bigger and substantially more expensive. Since they spin rapidly, they wear out quickly. Hubble normally runs on three, and can do OK on two (it usually has six: three are backups). Two are not functioning any more, and it’s only using two now; two functioning gyros were shut off to preserve them. The gyros can be replaced as well, and they have been in the past.
The problem as it stands now is that the remaining ones are getting old (they were installed in December 1999). If it has to, Hubble can limp by on one gyro, but if that last one fails, Hubble will start to tumble. That’s a disaster: if that happens no rocket can dock to it to fix it! So time is important. If we’re gonna fix it, it needs to be done soon.
So NASA is pondering this right now. There are issues: the Shuttle is due for retirement in 2010, and there is only so much time to get the space station completed. Squeezing Hubble in may be a problem, especially since NASA lost quite a bit of time with the destruction of Columbia. Safety is a concern: it was mandated that the Shuttle needs to be able to reach the station if anything goes wrong, and it’s on a very different orbit than Hubble. The Shuttle can’t go to Hubble and the station. So the rules will have to be bent.
But I’m confident NASA will choose to go upgrade Hubble. Why? Well, for one, they recently relaxed the restriction that all launches be during the day (for safety reasons). That makes it easier to get to Hubble, and implies NASA is willing to take some small risks. Also, Mike Griffin, the NASA Administrator, has said that Hubble is a priority.
We’ll see soon enough. Engineers are scheduled to meet Friday, and rumor has it that an announcement may be made by Tuesday. I’ll have more info posted here when I find it out!
Finally, I’ll admit to a personal stake in this. I worked on STIS for many years, before it was launched. After many years of service, it shorted out in August 2004 and could no longer be used. If this servicing mission gets the go-ahead, there are plans to replace the dead parts on STIS, and it’ll be up and running again. I’d like to see that. Plus, two more great cameras will be put on board, and the boost to space science will be fantastic. It would be truly fantastic to see the grand old lady of space observatories back up to speed.
October 24th, 2006 at 10:17 pm
oh my fav camera!
October 24th, 2006 at 10:20 pm
They’ve either got to figure out a way to fix it or find a way to safely decommission it. They surely cannot let it go out of control to re-enter the atmosphere wheverever it happens to come down. That should be reason enough to either send up a shuttle mission or else let someone like Orbital Recovery bring it to a graveyard orbit.
October 24th, 2006 at 11:02 pm
I’m with lucid. I don’t know about the cost benefit of Hubble science but I sure do enjoy the view.
October 24th, 2006 at 11:28 pm
I have a 1985 volkswagen golf GTI that runs and looks like new it’s over 20 years old.. why does it look and drive like new cause it’s built well and I upgrade the parts and look after it….it saves me $$$$
nuff said
October 25th, 2006 at 1:18 am
Why is finishing the space station so important? There must be dozens of unmanned planetary missions that could be launched with that money.
October 25th, 2006 at 7:01 am
I hope Hubble does get serviced. Certainly, it’s one of the best investments in space science.
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.
October 25th, 2006 at 7:32 am
Most of the budget sacrifices at NASA are killing earth science programs, not exploratory programs. And, of course, there may be alternative motives for that particular choice of sacrifice… But that’s for another thread.
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.
October 25th, 2006 at 8:22 am
I thought the gyros were running on magnetic bearings? No physical contact should imply no degradation. Or am I just plain wrong???
GAry 7
October 25th, 2006 at 9:13 am
And, another very great reason to service the Hubble:
“NASA’s Hubble Space Telescope has provided astronomers with the best observational evidence to date that globular clusters sort out stars according to their mass, governed by a gravitational billiard ball game between stars.
“Heavier stars slow down and sink to the cluster’s core, while lighter stars pick up speed and move across the cluster to its periphery. This process, called “mass segregation,” has long been suspected for globular star clusters, but has never before been directly seen in action.”
the Staff Writers at Space Daily
October 25th, 2006 at 9:14 am
HST is the only reason left for the existence of the Shuttle programme.
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).
October 25th, 2006 at 9:45 am
If I’m not mistaken I remember the original intent was that at the end of the HST life it was to be brought back to Earth for display in the Smithsonians Air & Space Museum. The HST should come back home…
October 25th, 2006 at 10:16 am
Small typo: “and out in the new”. Should be “and put in the new”.
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 )?
October 25th, 2006 at 10:30 am
Uh, compwest, the problem here is that we don’t have to launch a 2 million kg spacecraft up a gravity well every time your car needs servicing.
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.
October 25th, 2006 at 12:25 pm
[…] “Hubble servicing mission to be decided soon“, no Bad Astronomy. Ainda a missão de serviço ao Hubble, cuja recente avaria tornou muito necessária; […]
October 25th, 2006 at 12:55 pm
BA says: “There are gyroscopes on Hubble that keep it stable and locked on its targets… Hubble normally runs on three, and can do OK on two…If it has to, Hubble can limp by on one gyro…”
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
October 25th, 2006 at 1:20 pm
ioresult,
“…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
October 25th, 2006 at 1:27 pm
Jack,
“…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
October 25th, 2006 at 1:45 pm
Hey Phil! It’s Hugo. I love the revamp to the site. Also, I’ve been trying to reply to you regarding my renewal for universitydegreefinder.com, but I haven’t heard back from you (did you get the payment or any of my e-mails?)
October 25th, 2006 at 1:49 pm
The HST should definitely be kept running. Even if you ignore the scientific results that HST has helped us achieve, the stunning pictures have gotten many people interested in science and space, e.g. the Eagle Nebula, Deep Field, various galaxies, etc.
Make we should take some of the billions we sunk into Iraq and give it to NASA…
October 25th, 2006 at 3:06 pm
“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?”
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.
October 25th, 2006 at 3:30 pm
Wow, I just learned about the Sagnac Effect. How do you pronounce it? San-yak?
October 25th, 2006 at 6:20 pm
Lorne -
Thanks. That’s why I keep coming to this site. I wind up learning more about subjects I thought I knew about. Cool.
- Jack
October 25th, 2006 at 10:42 pm
One suspects Hubble will be sacrificed for the Moon mission as budget cuts continue o bite.
Sorry, but the betting is on no rescue mission and more cancelled science missions.
October 26th, 2006 at 1:01 am
[…] Bad Astronomy Blog » Hubble servicing mission to be decided soon I said I would do some more on Hubble. This is the thing I alluded to, about whether Hubble will be maintained. (tags: hubble astronomy images) […]
October 26th, 2006 at 1:25 am
Just wondering: if there are 6 gyros up there, and 2 are not working and 2 are failing, is there no use for the remaining 2, “shut off to preserve them”?
October 26th, 2006 at 8:04 am
The problem of letting Hubble come back down on its own has been, I believe, the main mirror - that big ol’ hunk of glass will be coming down like a giant Frisbee of Doom, and it probably won’t hit any populated areas, but… So having a fleet of Hubbles without a deorbiting plan wouldn’t be the best idea in the world. Would it be possible to build self-deorbiting capabilities into a hypothetical new-style Hubble?
October 26th, 2006 at 9:02 am
Maurizio Morabito,
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.
October 26th, 2006 at 10:07 am
“Of course we immediately start making those new Hubbles it will be years before the first one will be ready for launch. ”
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?
September 22nd, 2007 at 11:15 pm
Maybe you guys haven’t had a good laugh yet, this may be your chance. Please bear with me, I’m going to float a wild idea. As decommissioning looms, I’m thinking that the hubble could have a second mission. To the best of my understanding, we still have a long way to go developing a strategy to detect and stop asteroids that would be on a collision course with earth.
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.