ISS MER Management’s Daily Notes Tuesday, June 19, 2001 (GMT 170) – 12:00 pm
The following notes highlight the ISS activities within the last 24 hours that were discussed during the morning NASA and Boeing management teleconferences, as well as the daily MER Management & Subsystem Tag-Up. These notes are not intended to provide the current configuration of the ISS systems, nor are they intended to capture all of the events that have occurred in the past 24-hour period or that are planned for the next 24-48-hour period. For a detailed overview of the last 24-hour period and upcoming ISS events, refer to the “0800 Report” and “Daily Report”, published by MOD on its Mission Control Center (MCC) website at http://mod.jsc.nasa.gov/mcc (select “Realtime Mission,” then “ISS Msgs”).
DDCU LA1B and LA2B EEPROM Bit Flips: Two new EEPROM bit flips occurred last evening, one in each of the core Lab DDCUs, DDCU LA1B and DDCU LA2B. The DDCU LA2B bit-flip was detected as part of the weekly BDTs performed to detect health flags on ORUs without the health flag. The bit flip is in Block 15, a non-critical section of firmware containing ground-only code. DDCU LA1B previously had a bit flip in non-operational code within Block 14. Daily BDTs evaluated by the MER on Monday evening showed an additional bit flip in Block 10, a critical section of code. Block 10 in the firmware contains code for Trip Processing, Hindsight Buffer, and most importantly Mode Code and Command Processing. The command processing validation includes subaddress checks, latching data, reset R/T, converter on/off, arm/fire, common clear, and commanded BIT. All of block 10 will be dumped and forwarded to Canoga Park for analysis to determine the exact location and function of the flipped bit. Whether immediate action is necessary and prudent will be determined from the results of this analysis.
Refreshing these DDCUs requires a CCS software patch. A request to prioritize development of the patch will be brought forward to the ASCB. Once the patch is developed and tested, the refresh procedure will be verified in SPEL, and most likely an ORT (i.e., MOD commanding from MCC to test bed).
DDCU P62B Refresh: The Flight Control Team discontinued this procedure when the validation dump of the patch after it was uploaded (and prior to the start of the actual refresh) did not match the expected value. Investigation determined that the expected value provided to the FCT was in error. This value will be certified and retransmitted to the FCT. Expect that refresh can be re-attempted tomorrow.
Spare SASA / Prime SASA RT Conflict: The ART met yesterday afternoon to finalize its options for resolving the spare SASA / Prime SASA RT Address Conflict Issue. The spare SASA and prime SASA have the same RT address and share the same data bus. If the spare SASA were to be powered up while the prime SASA is powered up, the resulting conflict would cause a loss of communications and potentially damage the bus. The temporary “fix” has been to issue a flight rule (in development) to prohibit powering up of the spare SASA. When 7A.1 is flown, a Y-Jumper is going to be installed that will cause the spare SASA to automatically power up and induce the conflict. The team will be proposing 2 options for resolution to management: (1) modify the Y-Jumper to remove the 1553 pins, thus allowing the spare SASA to be powered and providing thermal redundancy, but utilizing some of the hardware life; or (2) do not make any hardware modifications, but change installation configuration so that one end of the Y-Jumper is not installed to the spare SASA, thus leaving it un-powered and thermally zero-fault tolerant.
Node 1 RPCM N13B-A: PHALCON reported that they are unable to close RPC-1 in RPCM N1-3BA. The RPC powers the Emergency Egress Lighting Power Supply within the Node 1. Several close commands were sent. All commands were accepted but the RPC-1 switch status telemetry (based on RPC output voltage) never showed the RPC closed. However, BDTs show the discrete output status of the RPC as closed. In other words, internal telemetry shows the RPC is closed but external telemetry shows it is open. An ART has been formed to investigate.
New IFIs Generated Within the Last 24-Hours
IFI 438, SSRMS Load Cell Drift
IFI 439, RHC Slide Switch
IFI 440, RPCM N13B-A RPC1 Did Not Close When Commanded
Today’s Events (GMT 2001/171):
PCU Testing (continuing throughout the week)
TVIS 6-Month Maintenance
Upcoming Events for GMT 2001/172-174 (i.e., Wednesday, Thursday, Friday):
Wednesday: Payload operations
Thursday: Payload operations, SSRMS operations and DOUG test, ROBO conference
Friday: IWIS / TVIS Test
Other Upcoming Events:
SASA/Spare SASA/EAS Connectivity Issues – presentation to the 7A.1 JOP and ISS Daily, Tuesday, June 19, 2001
ESP-1 PFCS R&R ART – Tuesday, June 19, 2001, 9am, MER Conference Room
BGA ART – Tuesday, June 19, 2001, 12:30am, MER Conference Room
MCOR ART – Tuesday, June 19, 2001, 3pm, MER Conference Room
RPC/DDCU ART – Wednesday, June 20, 2001, 3pm, Location TBD
Smoke Detector ART – Thursday, June 21, 9am – MER Conference Room
