Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!henry From: henry@utzoo.UUCP (Henry Spencer) Newsgroups: net.followup,net.astro Subject: Death of Ground Based Astronomy Message-ID: <4301@utzoo.UUCP> Date: Mon, 10-Sep-84 19:55:26 EDT Article-I.D.: utzoo.4301 Posted: Mon Sep 10 19:55:26 1984 Date-Received: Mon, 10-Sep-84 19:55:26 EDT References: <498@ames.UUCP> <443@utastro.UUCP> <370@aquila.UUCP> Organization: U of Toronto Zoology Lines: 93 Several people have responded to my suggestion that ground-based astronomy is dead, mostly with sharp denials. I stand by my previous comments, however; these folks have missed the point. The claims that ground-based astronomy is not going to die are all based on one fundamental postulate: P. Access to space will remain expensive and infrequent. From which we get four theorems: T1. Space-based telescopes will be few. T2. Observing time on space-based telescopes will be scarce. T3. Space-based telescopes and their instruments must be built to be ultra-reliable. T4. Since there are few telescopes, they and their instruments must be as sophisticated as possible to maximize results. If one agrees with these assumptions, then obviously space-based astronomy can *never* do more than supplement ground-based astronomy. Unfortunately, all these assumptions will shortly become wrong. Access to space *will* become cheap and routine; the only question is how soon. I know some people who think it *might* be within the next 10-15 years. Certainly it will happen sometime within the next few decades. (Note that the Shuttle is not cheap and use of it is not routine and probably never will be, despite the original hopes. It will take second-generation hardware to achieve the effect I refer to.) Let us re-examine theorems T1-T4 on this basis. T1 becomes false. Space-based telescopes will be easy and cheap to loft, hence plentiful. The biggest hassle will be uplinks and downlinks. This is probably best handled by having most of the telescopes near one or more space stations, so they can use part of the stations' ultra-high-bandwidth communications gear. This aside, setting up a space telescope becomes not much harder than setting up an observatory on a nearby mountain. T2 becomes false. Anyone who has a real need sets up his own telescope; minor users share existing instruments. There is no drastic shortage of scopes, hence no drastic shortage of observing time. T3 becomes false. With routine access for maintenance, there is no reason why (say) a photometer for space use has to cost much more than a similar instrument for ground use. Most current ground-based instruments would work just fine, albeit briefly, in space. Most could be upgraded for a fair useful life in space with very minor changes, i.e. vacuum-tolerant lubrication for moving parts and remote controls for adjustments. The space environment is a bit more severe than the ground-based environment, but not horrendously so. The big price tags on space-qualified gear are mostly a matter of ultra-high reliability and spectacularly inefficient bureaucratic organizations. [Those of you who doubt the last should look at the costs for the amateur-radio satellites, which are orders of magnitude below those of similar "professional" satellites.] T4 becomes false. Space-based instruments can be built for specific jobs in much the same way as ground-based instruments, and there is no need to eke every last possible bit of performance out of them -- there'll be another one next week, after all. This is a powerful factor in bringing costs down. Getting the maximum possible performance costs a bundle. In other words, given cheap and routine space transportation, ground-based astronomy dies. Setting up a major, or even minor, telescope on the ground makes no more sense than setting one up in the middle of a major city. It's just the wrong place. None of the critics has come up with anything that refutes my major contention: the right place for astronomy is in space. Putting it on the ground has *no* *advantages* except cost. Once access to space is easy and cheap, ground-based astronomy is dead except for secondary purposes like training. [Those who protest that mid-city telescopes are still good for something should go talk to the Carnegie folks; they've got a 100-inch telescope they'd like to sell you. The Mount Wilson observatory, including the original 100-inch telescope, is for sale. It's too close to the suburbs of L.A. now. I'm sure they'll be delighted to see you, because rumor hath it that there are no bids so far...] > >............-- and by the way, astronomers who oppose it are cutting off > >their noses to spite their faces... > > ... > And I know of no astronomers who are opposing the space station, and since > I know a lot of astronomers, it obviously isn't widespread. You've never heard of Carl Sagan? Last I heard, he claimed to be an astronomer. Ditto James Van Allen, whose name should also ring a bell. It doesn't really matter how widespread it is; influence matters more than numbers. A good many influential folks in the astronomy-and-space- science community have made unfriendly noises about the space station, on various grounds. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry