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From: starrfie@hydro.la.asu.edu (Sumner Starrfield)
Subject: Servicing mission (fwd)
Date: Sat, 4 Dec 93 9:31:29 MST
Forwarded message:
>From wms@stsci.edu Sat Dec 4 09:17:45 1993
Date: Sat, 4 Dec 93 11:24:32 EST
From: Robert Williams <wms@stsci.edu>
Message-ID: <vsnet-history1820@hoge.baba.hajime.jp>
To: starrfie@hydro.la.asu.edu
Subject: Servicing mission
>From DOXSEY@avion.stsci.edu Sat Dec 4 08:44:46 1993
Subject: SM report 2 - HST firmly berthed in Endeavour cargo bay !!
To: wms@stsci.edu, elt@astrovax.princeton.edu, grepass@gsfcmail.nasa.gov,
GILLIL@stsci.edu, weaver@stsci.edu, mcgrath@stsci.edu,
storrs@stsci.edu, ~saha@avion.stsci.edu, mackenty@stsci.edu,
~library@avion.stsci.edu, rjallen@stsci.edu, LONG@stsci.edu,
sbaum@stsci.edu, ford@stsci.edu, SESD@avion.stsci.edu
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SM Report #2
9:00 AM December 4 338:14:00
Summary of recent activities:
It has been a very successful day, HST is now safely berthed
in the Endeavour cargo bay.
During the day the final HST preparations for rendezvous
and berthing were carried out. The HGA dishes were moved to the
proper berthing positions and then the HGA masts were driven to
the stowed position, parallel to the telescope tube. In both cases
the HGA mast microswitches indicated that the HGAs were properly
stowed, but the latch microswitches did not indicate that they
were in the proper position for latching. The latches are mechanical
devices which grab the HGAs to provide structural support during
launch or reboost. The current plan is to have the crew inspect
the latches, either by TV or during one of the EVAs(more about this
later). The latches are only needed for the reboost, which is between
EVAs 4 and 5 so there is plenty of time to solve the problem.
As the shuttle closed to within a few miles of the HST several
HST components (FGSs, FHSTs, etc) were turned off to conserve power.
As the shuttle neared within a few thousand feet the HST was rolled
about the V1 by more than 100 degrees to the proper grapple attitude.
This was a power negative attitude, with about 3 hours of time available
for the grapple and berthing. The shuttle crew continued their
rendezvous manuevers very smoothly, slowly closing the distance to
HST. The RMS arm was used to grapple the fixture on HST. Watching
the HST gyro data in OSS, we could see the precise moment when the
arm made contact with the telescope. The HST was then maneuvered over
the FSS and lowered onto it. The three mechanical latches on the FSS
were activated and grabbed fixtures on the bottom of the telescope.
The umbilical was then connected and HST switched to run from orbiter
power. Power was restored to the systems which had been shut down.
We later learned that the rendezvous required 145 pounds less
propellant than budgeted. This increases the propellant margin for
the remainder of the flight.
During the berthing sequence one of the payload bay TV cameras
showed a very noticeable kink in one of the bi-stems of one of the solar
arrays. The others looked reasonably good. This was not entirely unexpected,
analysis of the solar array bending phenomenon had indicated that
there were likely very large motions of the arrays from day to night
which could have twisted or distorted the bi-stems. The crew then used the
camera on the RMS arm to conduct a TV survey of the HST. The HGA latches were
inspected and then closed. At this point it appears that the HGA latches
are gripping the HGAs sufficiently to allow the reboost.
Problems/Issues/Changes under consideration:
The JSC, GSFC, and ESA engineers are reviewing Solar Array
situation. NASA select was indicating that some were optimistic
that the arrays would retract, even with the kink. Peter Stockman
reports that ESA has done ground tests and successfully retracted
arrays with kinks of the magnitude seen in this bistem. If they fail
to retract properly, then they may be removed and jettisoned.
Near-term plans:
The first EVA will start at roughly 11:00 pm - midnight
on Saturday night. The EVA plans are basically unchanged, the gyros
(RSUs) and gyro electronics (ECUs) will be changed out first.
Then the fuse plugs will be changed. This will require powering
the SIs down for a short time, then back up. Some work will
be done on the Solar Array carrier in preparation for the second
EVA. At the end of this first EVA the solar array blankets will
be retracted. This activity will take place while the EVA crew
is still out in the payload bay. If one or both arrays fail to
retract then they will probably be jettisoned on the next EVA day.
Return to the Powerful Daisaku Nogami
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