31 October 2006

Hubble Saved!


It's official, there's going to be one more mission to service Hubble in 2008!


As I described in more detail elsewhere, there's a few things that I feel are crucial to a useful mission:

  1. Boost the telescope's orbit

  2. Replace the dying batteries

  3. Replace the dying gyroscopes

Things like upgrading cameras are a bonus. Also, keep in mind that this mission does NOT solve the issue of what to do when it "dies" - re-enters the atmosphere. Parts of the main mirror will probably survive re-entry (that is, not burn up), and it's been estimated that there's up to a 1 in 700 chance of human fatality from an uncontrolled descent. NASA still has not addressed that concern.



Mushy said...

I understand and appreciate the beautiful photos we've enjoyed for the last 16 years, but is it really worth the cost and risk?

Isn't it time for some new technology?

I understand there will have to be 2 shuttles involved in case of emergency, since the space station will be too far away, and that there will be 4 or 5 space walks.


zandperl said...

Hi Mushy, good points.

First off, you are correct that there will be five spacewalks. However the very first mission to the HST (STS-61, 1993) also had five spacewalks. In addition, two of the astronauts to be on the mission are veteran spacewalkers. One has already performed 5 walks working on the Hubble - three on STS-103 (1999), and two on STS-109 (2002). Plus it's worth pointing out that as far as risk goes, it's not in the spacewalks, it's in the launch and reentry.

Second, yes it is time for new technology. However, this repair mission will in no way jeopardize the exisiting Spitzer Space Telescope (which is newer than Hubble and just as good, but in the infrared and therefore less well known), nor will it change the scheduling of the James Webb Space Telescope (set to launch circa 2013, hailed as Hubble's successor despite the fact that it is also primarily IR).

In addition, the Hubble is oversubscribed by somewhere between 1:6 and 1:9. This means that for every hour that actually exists in a day, there's between 5 and 8 hours of requested time for good research that have to be rejected just because there's not enough hours in the day. The launch of Spitzer didn't remove this oversubscription partially because it's in IR and not visible, and neither will the JWST. Even if it does help, that is only a good thing. Should most astronomers move over to using the JWST, then the "less worthy" (but still damned good) research can still be done on the HST.

As for "worth the cost and risk," that's definitely debateable. Bang for your buck, Hubble's lightyears ahead (har har) of any other telescopes. The whole thing was BROKEN when we sent it up. If we'd never been able to repair it, it would have been so much scrap metal orbiting in space. (Well, that's an exaggeration, we would've come up with a mathematical way to help clear up the physical problems, but it wouldn't be nearly as good.) Hubble's had more than its fair share of a lifetime, and for much less money than would be spent on a new telescope, we can extend its life by years with a single service mission.

As for risk to human life, who knows. Astronauts willingly volunteer their lives and deaths for the pursuit of knowledge. If they didn't think it was worth it, they wouldn't do it. But yes, we should minimize the risks to them as valuable human lives (and valuable finite resources as well). How big is the actual risk? Who knows.