snidely@inteloa.intel.com (David P. Schneider) (04/29/89)
I had a random thought, brought about by the Magellan/Galileo trajectory
discussions.
The point made in those discussions is that the IUS is too light for any
but low-cost Hohmann transfer orbits. The random thought is, why not take
1 or more IUSs up on preceeding flights, park them, and then during the
space probe flight, and "stack" them together to make a larger transfer
agent.
There are two configurations of interest. The first is the "staged" ef-
fect, where the CofGs are along the line of flight, and the units are fired
in sequence. The second is the "tripod", where 3 (or maybe 4) are used as
the "feet" of a common frame, which supports the payload, and all fire to-
gether.
Some one else must have thought of this already, so why don't we do it? Is
the improved Delta-Vee still too small to avoid extremely slow transfers?
Is there too much problem getting IUSs parked? (I admit that it would
probably require quick timing -- both launches within the same month,
perhaps; could the parking be done by an unmanned booster?) Or is it techn-
ical problems in adapting the IUS?
Finally, what are the technical problems in adapting the IUS? How soon
could adapted units be available? Would it be easier/faster to design a
new staged solid fuel transfer agent than to adapt the IUS?
The dream, of course, is being able to miss the current alignement of
planets, but still to arrive at the target at nearly the same date.
Thanks for listening.
Dave Schneider
Friday, 4.28henry@utzoo.uucp (Henry Spencer) (05/02/89)
In article <4356@omepd.UUCP> snidely@inteloa.UUCP (David P. Schneider) writes: >The point made in those discussions is that the IUS is too light for any >but low-cost Hohmann transfer orbits. The random thought is, why not take >1 or more IUSs up on preceeding flights, park them, and then during the >space probe flight, and "stack" them together to make a larger transfer >agent. The official NASA position is that on-orbit assembly is Really Difficult and hence is unacceptable for mission planning. If it was allowed, one wouldn't mess around with IUSes; one would take the payload up on a shuttle and mate it with something like a Centaur launched by expendable. So we're back with the chicken-and-egg problem, again. On-orbit assembly will remain untried, and hence officially Not To Be Relied On, because it's officially Not To Be Relied On and hence nobody can use it. -- Mars in 1980s: USSR, 2 tries, | Henry Spencer at U of Toronto Zoology 2 failures; USA, 0 tries. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu