"Lucky" Camera Technology Blows Away Hubble

[superadvisor]

Come on guys, let us go back in time and stop them from launching the Hubble in to space, we can take the saved money and buy lots of land.

[Arp220]

This is really pretty simple. HST has done science that no other facility has done. Furthermore, it has done science that smaller, cheaper satellites (that could have been built during the 1980s and 1990s, we can of course do better now) could not even in principle have done, even if you launched a dozen of them.

I suspect your friends at GSFC are very competent and good at their jobs and so on, but have never written a science paper based on HST (ie one that goes to ApJ or AJ or whatever). I, on the other hand, have written a bunch of them. And their assessment of the scientific impact of HST, in absolute, relative, and 'what if' terms, is substantially off the mark.

The reason for this is that HST has a 2.4 meter primary. In ground based terms thats small, but in space based terms thats HUGE (for a shorter wavelength telescope). Spitzer, for example, which has cost about a billion all told so far, and which operates in the mid-infrared, has a 0.85m primary. Building and launching a satellite with such a big primary was, and still is, extremely expensive. If you want to launch a satellite for half a billion you simply are not going to get such a big collecting area - and so you're not going to get to do the same science.

Examples of the absolutely unique science HST has done includes:

1 - Sub L* galaxies at z>6
2 - Morphological transformation of galaxies at 1<z<4
3 - Zodiacal dust around other stars

I could list dozens and dozens of examples.

Regarding tying HST to the shuttle - thats a far murkier issue. Its certainly arguable that HST should have been launched on an unmanned rocket into a higher orbit, but then again, if it had, then the mirror could never have been corrected for, new instruments and gyros and so on could ever have been installed... HST would have had a lifetime of about 5 years instead of 17, and would have never lived up to its full potential.

Maybe we're talking at cross purposes here. My contention is that HST has been very good value for money, but that in hindsight we could have done somewhat better with the same money. My perception of your contention is that your saying that HST has been a waste of money, and that this was known for a fact from the beginning and could have been avoided. If this is what you are saying then you really are talking complete bilge - see the paper I gave a link to.