ISS MER Status 9 Feb 2001
Excerpt from: 9 February 2001: Felicity Vol. 46 (Acrobat 1.8 MB)
EEATCS Outlet Temp. Toggling
After PVCU MDM activation at GMT 338/ 22: 20, the EEATCS loop A & B temps were both
reading around -9 deg C. At these temperatures, it would be expected that the low temp.
Message would be issued once and remain in- alarm. Currently the EEATCS Loop A& B
Outlet temps are within limits. A test was performed on 12/ 18 to measure the Min Out FDIR
response. During the test on 12/ 18/ 00 the events 1303 and 1304 were suppressed prior to
the test. CHIT ISS 0084 documents plan to data dump the PV MDM if this condition recurs.
Boeing – CP is reviewing data. C& DH and TCS teams continue to look for more useful data.
No known impact from this toggling.
SSC Network not Functioning
The crew was not been able to set up the SSC network. On GMT 2000/ 335- MOD uplinked
Printer troubleshooting procedure to crew via OCA (OCA_ 0335). Printer problem turned out
to be a cabling problem. Crew resolved problem. Reference OCA message 335. Network
became operational after replacing a network card and the OCA laptop on 4A. The IFI will
be closed once a FIAR is generated. Some assistance may be required from the ISS crew
to retrieve the serial number of the PCMCIA card (bagged and tagged by Shep) for FIAR
documentation.
PCU Tubes Never Reached Temp When Heaters Were Active.
For both PCU 1 & 2, the Tube Temperatures are 10 deg C below their expected value.
The tube temperatures should have reached operating temperature and started cycling
between 32 and 42 deg C, but have steadied out at approximately 30 & 33 deg C each. The
temperatures are varying with Beta angle, with the tubes colder at negative Beta angles.
The Tube Heaters remain ON constantly, providing 15W of heat to the tubes. Short- term
plan is to Operate both PCUs in discharge mode. Other options are 1), to Use Cathode
Heater to warm PCU in ease of sever need, this is relegated to one time Use only. Further
testing is required authorizing use. 2) Use cathode heater to warm PCU tubes when
ignition is necessary, GRC to evaluate use of Cathode Heater Multiple Times. Requires life
testing (2yrs+). 3) Certify PCU for liquid Xe, more work on ROM needs to be done. 4)
Increase Tube Heater size, more work on ROM needs to be done. VCB – Post 5A Mission
or earlier. Is to make decision on which Option to chase.
BGA 4B Anomalous Signatures in Rate Mode.
The BGA experienced a current spike while solar array was rotating. The working theory is
that this was due to thermal effects causing friction in the assembly. Anomaly Review Team
has been formed and has arrived at the following conclusions: 1) the “Event” appears to be
a “6- Sigma” occurrence, well within system operational capability, 2) no data to suggest
BGA performance is degrading, 3) most likely cause is thermal gradient effects on BGA
main bearings. Findings to be presented to VCB for closure of issue. on 02- 05- 01
FPP Failure To Acquire Data.
The FPP Software application on the SSC computer has been up graded, changing the
communications protocol with the FPP probe on P6. This has allowed normal communication
with the FPP, and the Plasma Specialists are currently analyzing the data.
OCA Headset Cable Failure
Crew OCA headset can listen but not talk. Problem isolated to OCS headset cable.
Troubleshooting of cable indicated no connectivity in microphone leg of cable, isolated to
microphone jack itself. Also, per Fli ght Note OPFN961, the Crew has also reported problems
in earphone le g. The Crew performed tests and attempted repairs as noted in Flight Note
OPFN961. Apparently the mic side was repaired to functionality by splicing a jack from a
Sony CD speaker. Then it was discovered that the Earphone cable was in operative. Not
having the parts to do a repair to the Earphone side, the Crew used the laptop external
speakers. This gives the Crew a patched system that is presently providing voice transmit
and receive. A new cable will be flown on fli ght 5A. FIAR to be issued.
Orlan Suit problem with comm
C& T, has been working the issue. A telecon with Russian C& T & EMC counterparts was
held. Currently preparing new test plan & procedure. New test to be conducted in 2- 3 weeks,
Post 5A/ Pre 5A. 1.
IRED Loose Nut
The crew was having problems with a loose nut on the IRED hand crank. The nut is a brass nut
that holds the handle portion of the crank to the crank body. With some info from the ground,
the crew was able to ti ghten the nut and it seems to be ok now. However, they also requested
some way to make sure the nut would not loosen a gain. Since there isn’t any locktight onboard,
a procedure was developed to apply Dycal dental cast to the threads of the bolt and reti ghten
the nut. The procedure has been PV’d and is ready for uplink if the crew decides it is needed.
TVIS Electrical Potential
The crew reported they experienced static discharge between them and the TVIS control panel when
exercising on the TVIS. The level of discharge was reported to be worse at certain times. The TVIS is
located in the SM. The shocks were strong enough to cause hesitation when needing to touch the control
panel. The TVIS control panel readouts reset due to the discharge if not discharged on the metal box. If
there are other vehicle critical components in the vicinity of the exercising crewmember, or if critical
hardware is brought into the vicinity touching this hardware could lead to failure of the hardware. Crew
static charge build up appears to be occurring every time a crewmember exercises on the TVIS. Once per
day times three. The source of the static charge build up is believed to be, a combination of the low
humidity in the SM, the treadmill belt, and the running material of the crewmembers shoe and clothing.
Purposed solutions are:
- Provide controlled discharge area.
- Use ground strap
- Modify TVIS to bleed off static charge through a riding bleed line.
- Ground though SLDs
Audio Dosimeter Failure
Acoustic dosimeter reading was lower than perceived levels. This problem occurred with all three
dosimeters and persisted until 2001/ 20: 00: 00. The problem occurred during regularly scheduled acoustic
readings. It is not clear where the reading were being taken but the crew report implies that the problem
persisted regardless of their location. After trouble shooting it was found that the factory gain settings (80
dB) were improper for the ISS environment and 40 dB needed to be added to the gain. This cleared the
problem with one of the dosimeters. The other two continued to experience problems. Neither changing
out batteries nor display verification corrected the problem. The root cause of the problem for the now
functioning dosimeter was that the factory settings required changing to be useful on- orbit, but no one
informed engineering in order address this during preparation of the hardware. As for the two remaining
malfunctioning dosimeters, no root cause has been found yet. The dosimeters are currently under study.
Proposed solution is to reset the dosimeter gain to 40 dB higher than factory settings. Revise hardware
processing drawing to reflect adjusting the gain. Perhaps a gain check should be added to the hardware
functionality verification.
IRED cord scraping
Crew reported a scraping sound coming from the IRED canister. Also some fraying was noticed on one of
the cords on the shoulder harness. The scraping noise was heard while exercising on the IRED at setting of
“8” and above. The IRED is located in the Node 1. Bottom cover has light grooves. The fraying harness cord
presented a safety issue. Crew has taken time to change out shoulder harness cords and might need to
trouble shoot canister. May have to restrict exercise to settings below “8”. This may present problems upon
return to earth (flight surgeon call). The scraping sound is possibly coming from an internal thimble that has
come out of position. More study is required to verify. No temporary solutions at this time. No fix for the cause
of the problem at this time. Investigation continues.
