Status Report

ISS MER Status Report 23 Feb 2001

By SpaceRef Editor
February 23, 2001
Filed under ,

EEATCS Outlet Temp. Toggling

After PVCU MDM activation, the EEATCS loop A & B temps began to cycle between in-
alarm and return- to- normal. 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. C& DH and TCS teams
continue to troubleshoot. No known impact.

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
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 at low Beta angles. Other options are
being considered for long term use.

Lab LTA Heaters Not Cycling

The six shell heaters were expected to cycle at approx. 60%, but were on continuously.
Evaluation underway to understand and recommend corrective action for future missions.


Ammonia QD Problems

M3 QD leak on Z1 tray. F1 and F3 detent buttons hard to depress on Z1 Tray. QD caps on
Z1 male QDs did not lock. Photos taken on EVA 3 and are under review.

EEATCS Radiator Deploy Indicator Error

Erroneous “deployed” limit switch indications on the trailing EEATCS radiator. Apparently a
switch problem. Switches may be sensitive to temperatures and/ or transient loads.

CDRA Air Save Pump Not Operating

CDRA Air Save Pump did not operate when attempting startup. Pump and cable to be flown
on 5A. 1.

TVIS Frayed and Snapped Wires

Temporary repair performed by ISS crew. Permanent fix being assessed at Anomaly
Resolution Team meetings.

CMG 2 Loss of Comm.

CMG 2 was safed by the flight software after loss of comm between the FWC and the
GN& C MDM was detected. Bus switching FDIR and FWC power cycle were performed
automatically. The system continued to control with 3 CMGs. CMG 2 now back on line.

Burned Wires On Veloergometer Control Box

During inspection of the ergometer, due to inoperable state, it was discovered that the unit had
a burned wire bundle. Spare parts being flown on 3P.

P6 DDCU 2B Health Flag

P6 DDCU 2B Health Flag was set coming out of a LOS. Data dumps showed the cyclic
redundancy check (CRC) failed in block 13. Failure in EEPROM and not SRAM. Common
clear was sent and flag reset after about 30 minutes of ops. SRAM refresh
commands/ procedure is in development by CP.


C& C1 MDM indicated a CCS HRDL MSD Access toggle from true to FALSE. The crew
attempted to reset per onboard procedures but failed. The ground issued a HRDL reset and
successfully cleared the indication. Crew indicated the PCS was back to normal. CCS and
PCS personnel are performing testing to attempt to duplicate the observed conditions.

Node 1 PMA Duct Missing Parts.

Duct tape was used. Under investigation.

Aluminized Kapton Bubbles on 7th radiator panel.

Bubbles observed in the alum. kapton tape on the end of the 7th panel of stowed radiator.
Requested EVA photos be taken for radiator deployment and future assessments.

K- Bar Installation Anomaly.

When crew attempted to install K- Bar on ARS rack it didn’t fit. Two additional racks fit ok.
Modified units flying on MPLM 5A. 1.

CMG Spin Bearing Heater Fault

Five occurrences to date on CMG 2. No impact to operations.

Unexpected EEATCS Loop A radiator return temperatures

Higher by 20 – 60 degrees than model predicted. Testing worked per Flt note THFN971. Temp
still higher than expected even after second radiator deploy (temp = -25 c). Data under review by
thermal team.

BGA Observed vs Commanded State

During progress 2P undocking a series of three 4B BGA observed vs commnded state failure
were observed. Progress thruster firing caused first, ISS vehicle regaining attitude control
caused second, third occurred during LOS.

SpaceRef staff editor.