On 3/31/04 5:38 PM, in article , "Jorge
R. Frank" wrote:

h (Rand Simberg) wrote in
:

On Wed, 31 Mar 2004 21:05:45 +0100, in a place far, far away, "John"
made the phosphor on my monitor glow in
such a way as to indicate that:

The change is 3kmps, which is about a third of the
acceleration that the shuttle needs to get into orbit in the first place.

What's your basis for that number? How much of a plane change were
you assuming?

His number is pretty close to mine (3.05 km/s). I assumed a noncoplanar
Hohmann transfer from HST (310 n.mi., 28.45 deg) to ISS (210 n.mi., 51.6
deg), for a total plane change of 23.15 deg. Delta-V is minimized by
combining most of the plane change (21.76 deg) with the first Hohmann burn.
Of course, both burns must occur at the moment when the RAANs are equal,
otherwise the plane change will be much larger than 23.15 deg.

Someone (Ed Kyle?) figured out a while back that such a delta-V would
require two Centaurs, for a spacecraft HST's size.
Jorge, what do you think about John's idea in an earlier post about using an
ion propulsion system to push Hubble into an ISS compatible orbit? Would
that be a viable option or would the development/ transition fuel costs,
etc. be too prohibitive?