shafer@skipper.dfrf.nasa.gov (Mary Shafer) (06/11/91)
A colleague (Lou Adornato adornato%asd.dnet@aio.jsc.nasa.gov) asked me
to pass this on, since he doesn't have access from this machine. Someone
who understands the technique of e-mailing to berkeley to post should
pass the information to both of us, please.
NOTE: The following is onofficial and unauthorized and should be taken as
heresay only (otherwise a guy named Bruno's going to come down from Washington
and rearrange my pulmonary system).
I am happy to report that there have been no orbiter DPS or avionics
concerns on this mission so far. (The reason I'm happy to report that
is that it means that Mike Wallace won't be showing up at my place
with a film crew). On flight days 4, 5, and 6 I'm the second shift's
avionics team lead in the Mission Evaluation Room (MER). Here's the
view of STS-40 from where I've been sitting.
Initial ground radar data indicated that STS-40 missed it's MECO
velocity target by 22 fps. Subsequent analysis of the observed
orbital elements now indicate that MECO velocity was within 4fps of
target, and that the radar data was incorrect. Further analysis is
planned post flight.
As of the end of my shift on Flight Day 5, there are no major IFA's on
any spacelab or orbiter systems, with the exception of the
environmental seal on the PBD and some loose thermal blankets on the
aft bulkhead. Thermal reports that there are no potential hazards in
the loose blankets. At this time it looks as though proper thermal
conditioning (via sun angle) will cause the seal to deflect away from
the door and prevent it from interfering with the latching mechanism.
(My understanding is that a failure of latch group 4 wouldn't be a
problem anyway - you have to loose at least 2 latch groups before you
have a situation) Contingency plans are being put in place for an EVA
IFM "just in case" (the incredibly unofficial motto of the Mission
Operations Directorate). Current plans are for one crew member to
reenter the hab module after deactivation to observe the PBD closing
(through the spacelab's endcone window). There was some concern over
the safety of this procedure since the cabin air fan will be off at
this time (it's turned off to save power as part of the deactivation
procedure, and running it without the condensate separator could
impact the turnaround for US MGL). The observer should be in the
module no more than 15 minutes, but a localized CO2 buildup (in the
absence of convection currents) was a concern. Analysis indicates
that there is no safety concern because several of the racks will be
forcing air into the subfloor, and there should be an air flow down
the tunnel from the middeck. Aditionally, the observer will be in
constant contact with the rest of the crew, and there's an emegency
breathing station right by the viewport.
One RCS vernier (R5F, I think) has failed off (due to erratic chamber
pressure readings, I think), but there's no impact on vernier attitude
control (the verniers are arranged in such a way that it would take at
least 2 adjacent jet failures to cause even an inconvenience). An
APU3 Exhaust Gas Temperature sensor failed on ascent (indicating
+/-200F changes is less than a minute), and the crosstalk took a gas
generator bed temp sensor with it. This isn't considered critical - I
can't be sure but I think there are redundant backups, and I don't
think either reading is really essential to safe operation of the APU.
An unknown problem resulted in the S/L computer being re-IPL'd on FD4,
but no experiment data was lost and the problem has not returned (dump
analysis is still in progress). The humidity seperator experiment
(DTO976, I think) was aborted early on FD2 because a large slug of
water broke off from the prefilter and temporarily swamped the humsep.
The PI suspected it might be a transient or startup condition. The
test was rerun yesterday, but not for as long as was originally
planned (due to timeline considerations, I think). Some free water was
detected by the crew in the lower equipment bay on the waste water
tank drain valve solenoid, but it was wiped off and the source wasn't
found - the crew will probably check again today to see if the water
has returned.
Other issues that have come up are include a loss of about 7lbs of N2
on FD1, which was apparently due to a leak through the WCS (the handle
wasn't thrown all the way after use, resulting in inadequet seal on
the WCS vaccum line (even in space you sometimes have to jiggle the
handle to make the toilet stop running). The OMS crossfeed line A
heater failed off (apparently due to a thermostat failure), and the
line has been isolated (there's a backup). The pressure 'ducer on the
RAHF (the rat-rack) water supply has failed, but the POCC will
determine water useage indirectly by using the Lixit counts from
individual cages along with pre-launch calibrations (which means that
someone, somewhere has a fairly precise number for the value of a rats
lick). Some problems with the Obriter Refridgerator/Freezer (ORF) have
caused it to be shut down, and several short IFMs have been done to
try to isolate the cause. Similar problems appeared on the S/L fridge
on FD1, but went away, so there's no risk to the samples. Also, a
strange smell has been coming fromthe ORF (the crew reports that it
smells like aldehyde), which is suspected to be acetic acid ougassing
from the silicone seals - toxicology says there's no risk to the crew.
One of the LIOH storage locker doors jammed on FD1, and the crew had
to pry it open, but it's been left open since then, and will be shut
for structural reasons just after the deorbit burn. The IV pump
experinent was having some problems on FD1, but the IFM guys had the
crew wrap a blood pressure cuff around the intake bag to provide
suffient head pressure (this one has to be my personal favorite
IFM...), and it's working fine. The GAMS 1 experiment (I have no idea
what that is...) has been causing some problems, but the crew's been
using the backup without any problems, and will probably try an IFM on
the last flight day. There have been some problems with one of the
video cameras, but I haven't been following them.
The rats seem to be enjoying themselves (they don't know what's in
store for them once they get back), and the jellyfish are healthy but
somewhat confused (probably a natural state in something with a
nervous system only slightly better than that of a slime mold, but
they've been swimming in circles).
No one had a chance to make a visual on the soviet MIR station on
either opportunity yesterday. Current consummable levels are good for
a 9+2 mission, with LIOH being the limiting factor.
Proper NASA terminology is "nominal" for the mission, but I prefer
"fan-dam-tastic". Considering the number of things that can go wrong,
I'm still astounded when things go this right. All that planning and
care really means a lot when it gets around to flight time. I wish
the news media had shown those views of the lower equipment bay that
came down yesterday. It's really sobering to think how many pieces in
there could cause a loss of *at least* mission success, and to realize
that this mission is coming off so well.
| This information is unclassified.
Lou Adornato | Material herein not cleared by the Public
NASA/JSC Engineering Directorate | Affairs Office. Opinions and attitudes do
Flight Data Systems Division | not reflect those of NASA. NASA takes no
Flight Software Branch (EK2) | responsibility for inaccuracies in my data.
--
Mary Shafer shafer@skipper.dfrf.nasa.gov ames!skipper.dfrf.nasa.gov!shafer
NASA Ames Dryden Flight Research Facility, Edwards, CA
Of course I don't speak for NASA
"Turn to kill, not to engage." CDR Willie Driscoll