re: Mir/shuttle undocking

Philip Chien (
Sun, 7 Jun 1998 18:54:59 -0400

Rick Brown <> asks:

>1) Does anyone know at what time tomorrow (8 June) Discovery is
>scheduled to undock from Mir?


>2) How soon after undocking can I expect to find a published elSet for
>Discovery (and where can I find it?)  Is it possible to find a predicted
>elSet prior to the undocking?

the interesting this is - according to JSC public affairs _THEY DON'T KNOW

According to the public affairs office (and you can decide for yourself how
reliable you consider them) the Alpha Magnetic Spectrometer (AMS) folks are
negotiating the altitude timeline with the flight dyanmics officers.  The
problem is AMS is only concerned with ATTITUDE, not ALTITUDE.

Normally the shuttle goes in to a slightly lower orbit than Mir (after all,
it's coming home so it's logical to lower its orbit).  But for this
particular mission half a fly-around will be performed, leaving the shuttle
above Mir when separation occurs.

According to Flight Director Paul Dye this is so they can go in to AMS
attitude as soon as possible.  THe flight plan leaves space for a
separation maneuver but doesn't specify direction or time.

So in this unique case it is possible to see Mir ahead of the shuttle.

The key question is will the shuttle maneuver to a lower altitude some time
later (and if so would it be enough of a difference to come in front of Mir)

or will the shuttle stay in the higher altitude until reentry, permitting
Mir to go ahead of the shuttle.

The other factor is the shuttle's remaining in space another couple of days
for AMS science instead of immediately preparing to return to Earth.

In either case it's a unique situation for the shuttle-Mir program.

BTW - I haven't calculated whether or not the shuttle will remain in orbit
long enough for it to 'lap' Mir (e.g. if the shuttle does maneuver to a
lower orbit then it gradually pulls further ahead of Mir on each orbit
until eventually it catches up from behind - or vice versa if the shuttle
moves to a higher orbit).

2nd BTW - standard Phil Chien shuttle sighting report.

Saw launch from 6 seconds before launch through solids separation.  *yawn*.
Much too hot though - gotta talk with NASA about air conditioning more of

Philip Chien, KC4YER
Earth News
world (in)famous writer, science fiction fan, ham radio operator,
all-around nice guy, etc.