Ian Stirling wrote:
When I was watching NASA-TV, I noted that the russians were unhappy
if the shuttle pushed the station more than 1m/s or so, WRT the next
progress.
Why is this?
Is there that little margin in the progress engines?


Progress has to carry as much cargo as it can. The higher the station,
the less cargo it can carry because they have to load more fuel. And
with shuttle gone for the foreseable future, Progress has to be loaded
to the brim with cargo. The next progress is in september so station
will still be "high" because the reboost was weeks late due to Discovery
launching late.

One can argue however that if progress has to spend more fuel to get to
the higher station, it will be spending less fuel to reboost the station
since the station will stayup a bit higher, so having less fuel when it
docks may not make that big a difference.

My guess is that it simply reduces margins, and they probably prefer to
have progress docked with more fuel for emergency manoeuvers to avoid
objects etc.