andrew@tvcent.uucp (Andrew Cowie) (01/30/90)
In article <1990Jan28.012650.19697@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: [ Talking about not putting Hubble into geostationary orbit ] >The reason is economic: a low orbit maximizes payload with a given launcher. >HST is just too big for the boost up to Clarke (geostationary) orbit. [ I presume you mean STS in this case. ] Something I have been meaning to mention for quite a long time: I know that it is often said not to give ideas to NASA because they all ready thought of them, but would it not be practical idea to launch a booster package (say a couple of Inertial Upper Stages stacked together) using an Expendable Launch Vehicle, (Titan IV) Then using the shuttle launch the main payload, (see below) mate it to the booster, and fire it? Specifically, this applies to Galileo, and to Hubble. Galileo will take 5+ years to reach Jupiter, because NASA no longer likes the idea of lanching a shuttle with a large liquid fuel booster (Centaur?) in the payload bay. It must use three Gravity assist passes to attain sufficent speed to reach Jupiter escape velocity. If it had been directed towards Jupiter with a large, seperately launched booster attached, then there would be a much better chance of its arriving sooner. In Hubble's case, the telescope fills the entire bay. Thus there can be no booster to send it to geostationary orbit. If, however, the telescope was mated to a seperately launched booster, then it could attain a higher orbit without to much difficulty. I recognize that it is to late for this method to be applied to either mission, but this could probably be a workable alternative for future missions. It would also provide practice for astronuats in *real* orbital assembly. Comments? -- Andrew F. Cowie at TVC Enterprises, Toronto, Canada. uunet!mnetor!lethe!tvcent!andrew andrew@tvcent.uucp
roy@phri.nyu.edu (Roy Smith) (01/30/90)
andrew@tvcent.UUCP (Andrew Cowie) writes: > launch a booster [...] using an Expendable Launch Vehicle [...] using then > shuttle launch the main payload [...] mate it to the booster, and fire it? Why use an ELV to launch the booster? Why not send the booster up in another shuttle? Isn't the plan to eventually be able to launch two shuttles at the same time, or at least in quick (1-2 weeks?) sucession? -- Roy Smith, Public Health Research Institute 455 First Avenue, New York, NY 10016 roy@alanine.phri.nyu.edu -OR- {att,philabs,cmcl2,rutgers,hombre}!phri!roy "My karma ran over my dogma"
henry@utzoo.uucp (Henry Spencer) (01/31/90)
In article <1990Jan29.233938.8795@tvcent.uucp> andrew@tvcent.UUCP (Andrew Cowie) writes: >>The reason is economic: a low orbit maximizes payload with a given launcher. >>HST is just too big for the boost up to Clarke (geostationary) orbit. > >[ I presume you mean STS in this case. ] I'm not sure anything currently in inventory could put HST in Clarke orbit, actually, although it might be possible if you were willing to wait a couple of years for a Titan IV. Regardless of booster, of course, doing so means forgoing any plans to replace the instruments with second-generation ones (which are already under development) and likewise forgoing any hope of maintenance in the event of trouble. These limitations would be less troublesome if there were any plans for a successor to HST. >... would it not be practical idea to launch a booster package >(say a couple of Inertial Upper Stages stacked together) using an Expendable >Launch Vehicle, (Titan IV) Then using the shuttle launch the main payload... > mate it to the booster, and fire it? In-orbit assembly is officially Not A Problem for the space station and Far Too Difficult for anything else. Damned if I know why. It seems an eminently sensible approach. (Actually, I think I can guess part of the reason. The upper stages are not designed to sit in parking orbits for weeks at a time waiting for their payloads. Safety and manpower issues argue against trying to launch two shuttles in fast sequence, and NASA still prefers to do its launches in house [i.e. on the shuttle] rather than buying them from somebody else who NASA doesn't control. So in-orbit assembly is not politically feasible even though there's nothing wrong with it from a technical standpoint.) -- 1972: Saturn V #15 flight-ready| Henry Spencer at U of Toronto Zoology 1990: birds nesting in engines | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
tneff@bfmny0.UU.NET (Tom Neff) (01/31/90)
In article <1990Jan30.191717.9035@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >I'm not sure anything currently in inventory could put HST in Clarke orbit, >actually, although it might be possible if you were willing to wait a >couple of years for a Titan IV. Regardless of booster, of course, doing >so means forgoing any plans to replace the instruments with second-generation >ones (which are already under development) and likewise forgoing any hope of >maintenance in the event of trouble. These limitations would be less >troublesome if there were any plans for a successor to HST. They would also be less troublesome if there were a real Orbital Transfer Vehicle (OTV) in development. With an OTV you can de-orbit what you orbit, so putting an observatory into a higher orbit wouldn't preclude manned maintenance or upgrades, or even recovery. Some kind of OTV is a must if we're going to get better use out of near earth space in the coming decades. However I must agree with the previous poster that geostationary altitudes are NOT too friendly a place for delicate instrumentation. The detectors would be bathed in exo-Van Allen levels of radiation. Of course it would be nice to station an observatory directly above one ground facility wouldn't it. Let's hope that when a successor IS designed, we'll have the luxury of deploying it either geostationary or on the Moon.
nickw@syma.sussex.ac.uk (Nick Watkins) (02/06/90)
In article <15140@bfmny0.UU.NET> tneff@bfmny0.UU.NET (Tom Neff) writes: >In article <1990Jan30.191717.9035@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >Of course it would be nice to station an observatory directly above one >ground facility wouldn't it. Or even in the kind of orbit that the (1978) International Ultraviolet Explorer uses, which allows coverage from GSFC and Villafranca ... :-) >Let's hope that when a successor IS designed, we'll have the luxury of Lets hope someone capitalises on IUE and IRAS soon as well (yes I know there are successor missions)., Nick -- Nick Watkins, Space & Plasma Physics Group, School of Mathematical & Physical Sciences, Univ. of Sussex, Brighton, E.Sussex, BN1 9QH, ENGLAND JANET: nickw@syma.sussex.ac.uk BITNET: nickw%syma.sussex.ac.uk@uk.ac