crc (03/14/83)
I don't think you need much machinery to clean out the ET in orbit - the tank is surounded by vacuum. There have been proposals to use the ET for parts of a space station, like skylab. Check last year's aviation week for details. Charles Colbert floyd!crc
karn (03/14/83)
Getting the external tank into a long-lived orbit might not be as easy as many think. Remember, even the orbit into which the orbiter puts itself after ET separation is a very low one, typically 300 km or so. An object as large and light as an empty external tank would last hardly any time at all in such an orbit. Even moving it up to 500 km, which would take considerable added fuel on the orbiter (perhaps an OMS kit or two) would keep it up there for only several years at best. It is probably feasible to take a tank up to a stable altitude, but it would not be "almost free" as has been suggested; it would involve the sacrifice of considerable payload mass. Phil
earle (03/15/83)
The latest issue of Space World has an article on use of external tanks in orbit. One proposal is to tether a mass to the ET with a Kevlar cable and use tidal forces to keep the ET pointing forward in orbit, thus minimizing drag and extending the time before decay. Another is to use a similar cable between the orbiter and its ET on each flight: they would be spun about their common center of mass, and the cable cut at precisely the right moment, boosting the tank to a higher orbit and allowing the orbiter to reenter with little or no expenditure of fuel (thus boosting payload again). If the in-orbit ETs were rigidly linked together, each orbiter flight could boost the group slightly, eventually producing a large assembly of space station modules, complete with consummables, in a stable orbit. See the article for more (fascinating!) details. Earle T. Fettig GenRad Concord MA
preece (03/16/83)
#R:rabbit:-118500:uicsl:11100007:000:437 uicsl!preece Mar 15 09:15:00 1983 Sounds like a good job for a solar electric propulsion system - get the tank into a minimal orbit and let a little electric drive push it higher. It wouldn't matter that it took a long time, the drive would need to only produce slightly more thrust than the atmospheric drag and eventually the tank would get out to where it would be useful. Now all you need to do is build the propulsion system (whatever happened to SEPS, anyway...).
mabgarstin (03/23/83)
Wait a minute. grkermit!eagle said something about the orbiter somehow
flinging the ET into a higher orbit or something just before re-entry and
that a bunch of ETs could be ridgidly connected to create a large structure
of modules for space stations. This would undoutedly be some kind of a
lattice structure of ETs but since I just finished reading Larry Niven's
"Ringworld" last week eagle's mention of connecting ETs together conjured up
a picture in my mind of a ring of ETs around the earth all connected together
from which some platform could be built so as to support human life and
activity in a manner similar to Niven's Ringworld.
I believe that Ringworld discussions have already run the gamut on
net.space so I don't want to stir up any old and molding discussions about
such possibilities but if anyone out there has any string feelings or opinions
on this please mail me, I would like to hear from you. If any of you founding
members of net.space feel that it is time to start or restart Ringworld
discussions and that it would be of general interest to the net then do so, I
would be happy to join in.
~p
MAB
(...!decvav!utzoo!watmath!watcgl!mabgarstin)
P.S.-that should read "...strong feelings..." not "...string feelings.."