Comments on: Shuttle retry… and Hubble

By: Nigel Depledge

Nigel Depledge — Fri, 29 Jul 2005 22:55:54 +0000

Irishman – all noted.

I recognise that James Webb is more appropriate for viewing highly-redshifted objects, and that the L2 point might give it the potential for extraordinarily long exposure times (collecting photons from one patch of sky for up to 6 months, anyone?), but I think the value of Hubble is not down to science alone. I believe that the Hubble images have captured the imagination of many more people than all of our other space-based observatories combined (would you pay to have a poster of the WMAP data on your bedroom wall?). Consequently, Hubble has engaged more public enthusiasm (and therefore public funding) for astronomy than would otherwise be the case.

So I say “long live Hubble”. (Or at least as long as it is able to return such stunning images and such quality data).

By: Irishman

Irishman — Fri, 29 Jul 2005 16:10:24 +0000

Nigel, it depends on what the scope of the repair is. The plan for an automated repair mission probably would run that high, because that’s a whole new untried system with new equipment to build and test. The Hubble repair already has some work accomplished, has designs for some of the items (i.e. the gyros) already done, and we have astronauts who are already trained on spacewalks with Hubble, they just need mission specific training. Adding a new deorbit package for future contingency would up the price, but what you’re buying there is not operations of Hubble but safety when the final plug is pulled. A non-orbiting new telescope would be cheaper from that standpoint, because we don’t have to worry about it falling on Houston. Or Mexico City.

Yes, the shuttle grounding will impact the Hubble decision.

Why the James Webb doesn’t have visible wavelengths is because for looking farther in space, redshift comes into play and the visible spectrum can’t see that far – the visible stuff from there/then is in our IR bands.

By: Nigel Depledge

Nigel Depledge — Thu, 28 Jul 2005 21:04:15 +0000

Irishman – I think I also read somewhere that a Hubble repair mission (including specialised hardware and new pieces for Hubble plus training the astronauts for the mission plus the time spent in orbit (definitely need at least one EVA to repair Hubble, but may not need an EVA to deploy a new ’scope) etc.) would be more than a new space telescope.

But, the James Webb ST will not have optical wavelengths, plus will be orbiting at the L2 point (which I think means no option to upgrade or repair). Plus, Hubble has done more to publicise astronomy than any previous single instrument – I do not believe not having an optical space telescope is such a good idea. I know that, with modern adaptive optics, a ground-based scope can outperform Hubble in terms of resolution, but Hubble can get more reliable dark skies and can usually take longer exposures. Oh, yes, the Hubble Deep Field pictures were extraordinarily long exposures, that could not have been done by a ground-based telesope (wasn’t the Ultra-Deep Field about 20 days or something?).

So, even if a repair is more expensive, Hubble is probably worth it.

By: tjm220

tjm220 — Thu, 28 Jul 2005 18:20:38 +0000

Repairing Hubble likely won’t happen now with the fleet grounded. We’ll have to settle for a new scope.

By: Irishman

Irishman — Thu, 28 Jul 2005 15:36:37 +0000

A Hubble repair will cost MORE than a new telescope? Please justify that.

By: MaDeR

MaDeR — Thu, 28 Jul 2005 08:32:04 +0000

In my humble (hubble?) opinion, we should scrap this ’scope to the eternal rest – repair mission will cost MORE than new, shiny telescope with better parameters. In other words, new telescopes provide us with 100x better science that Hubble NEVER be able to give to us – and Hubble is black hole where money fall into without return.

By: Peter B

Peter B — Thu, 28 Jul 2005 04:30:54 +0000

Excellent interview with Paul Harris. It’s great to think that there are people on the radio who have such an open admiration for the space program, and so happily reminisce about the earlier programs.