Oxygen Problems Concern Space Station Managers
Editor’s note: The Expedition 14 crew has been unable to get the Russian Elektron Oxygen generation unit to operate normally. As can be seen below this has been an ongoing problem with serious issues arising more than a month ago.
According to this chart, without an operating Elektron the ISS should have enough Oxygen from residual supplies and SFOGs to last until 11 December 2006. Whereas this chart shows a 4 Feb 2007 date for total Oxygen supply depletion.
The STS-116 mission is slated for launch no earlier than 7 December 2006.
According to NASA International Space Station De-crewing and Re-crewing Plan SSP 50715
“3.2.1 CONSUMABLES CRITERIA Consumables and expendable hardware resupplies are tracked on a weekly basis by the FCT, MER, IMC, and IMMT to monitor actual versus planned usage rate for critical items. Criteria to initiate the planned de-crewing decision process are met when it becomes evident that one or more critical consumables will reach the 45 day limit. Estimated 45 day quantities for critical consumables are listed in Appendix D for reference. Contingency conservation plans such as using Airlock (A/L) Oxygen (O2) to save water, are evaluated and implemented to extend capability as needed.”
If Elektron continues to malfunction and/or STS-116 is delayed then this 45 day limit may be invoked – and a serious discussion about crew stay would focus on 21 December 2006 – which comes close to the 11 December date on one of NASA’s charts.
Of course, the more likely scenario is that the newly-repaired Elektron could function just fine – and STS -116 could visit the ISS on schedule.
See also:
- Service Module Atmosphere Revitalization Subsystem, Book 2, Mission Operations Directorate, 9 October 2000 [Acrobat], Section 5 for details on the operation othe ELektron unit.
- ISS Consumables Status: On-orbit Capability For 3 Crew (August 8, 2006)
- ISS On-Orbit Oxygen Without Elektron 18 Sep 2006 (chart)
- ISS On-Orbit Oxygen Status 18 Sep 2006 (chart)
International Space Station Management Center (IMC) Daily Summary Report
Stage 12A / Flight 13S Flight Day (FD)2
09/19/06 16:00 CDT 262/21:00 GMT
[Excerpts]
New Status:
Elektron Status: The crew reported this morning that the odor described during yesterday’s Elektron events came from the Oxygen (O2) outlet of the [__] Secondary Purification Unit and not from the rubber gaskets as was suspected yesterday. The odor could be organic and/or chemical. Today the Commander continued with Elektron troubleshooting activities today, including a pressurization test and purge of the O2 and Hydrogen (H2) outlet lines to help determine if there are any internal leaks in the O2 and H2 lines and associated equipment. No liquid was found during O2 and H2 connector inspections. Through the pressurization test, the crew reported the O2 line was leak-tight through sensor Light Emitting Diode (LED) confirmation. The H2 line LED sensor indication was absent. The current possibilities are a faulty H2 line sensor, a burned LED on the test panel, or a leak from the H2 to the O2 line in the Pressure Regulator. The crew also inspected the H2 outlet line after blowing N2 through the line, and no liquid was present. Russian specialists currently believe this is an indication that there is no Potassium Hydroxide (KOH) electrolyte being sent through the H2 outlet. Specialists continue to assess the data.
Solid Fuel Oxygen Generator (SFOG) Use: SFOG [___] “candles” will be used to generate additional O2 on ISS in anticipation of the Soyuz Joint Mission with 6 crew members. The plan was to expend 4 cartridges today and during the joint mission, manage the partial pressure Oxygen (ppO2) with both SFOGs and the remaining O2 on 22 Progress (P). There are 5 days worth of O2 left in the 22P resupply tank assuming 6 crew members. There are 40 “older type” SFOG cartridges remaining which will be used first. Once they are used, the old SFOG generator can be discarded. The new SFOG generator has been onboard for some time and there are 120 new cartridges available for O2 generation.
Previous Status (September 18):
Elektron Activation Attempts: The Elektron was nominally deactivated for the 12A Docked mission. This morning, the crew was scheduled to perform Elektron activation, which included compressing the [__] Water Buffer Tank located in the un-pressurized chamber of the [__] Elektron Liquid Unit. This procedure is used often, especially after Elektron has been down for an extended period of time. Compressing the tank assists in ridding bubbles from the pumps, as the presence of bubbles will cause pump shutdown. Once compressing was complete, Elektron was activated in 32 amp mode and within two minutes failed to the backup pump, which also failed within a few minutes. After several unsuccessful reattempts at activation in both 32 and 50 amp mode throughout the morning, the Elektron was finally activated in 50 amp mode.
Elektron Overheating and Fluid Leak: Within 3 to 4 minutes from the last reactivation attempt in 50 amp mode, the crew detected an odor and an increase in temperature of one of the purification units in the [__] Elektron Liquid Unit. The crew also reported at least one of the rubber seals between the purification unit clamps where it attaches to the [__] Elektron Liquid Unit had heated to the point at which it began to smoke. The crew deactivated the Elektron at approximately 6:00 am CDT and, at request of both Mission Control Centers, manually annunciated the Service Module fire alarm. Annunciation of the fire alarm resulted in automatic activation of the ___ (Russian atmosphere scrubber), and the crew activated the Vozdukh system. The crew monitored constituents in the ISS atmosphere using the CSA-CP and kept in constant contact with ground controllers. Throughout this event, Carbon Monoxide (CO), Hydrogen Cyanide (HCN) and Hydrogen Chloride (HCL) levels were well below the thresholds at which the crew would have been required to don gas masks. Therefore, the crew was not requested to wear gas masks by either Mission Control Center. A Spacecraft Emergency was declared at approximately 6:24 am by the US Flight Control Team to allow maximum satellite coverage for communications and commanding during the initial response timeframe. The Emergency condition lasted for approximately 2 hours.
The crew also noted a liquid bubble at the end of the Elektron O2 vent (which is exposed to the internal cabin). The crew and Mission Control Centers were unable to determine the toxicity of the fluid, and therefore donned protective gear (surgical masks, gloves, and goggles) in the event that the fluid contained Potassium Hydroxide (KOH). KOH has a Level 2 Toxicity (“irritant”), and could be released from the Liquid Unit in certain failure scenarios. The crew then performed the corresponding emergency procedures to wipe up and contain the liquid bubble the crew observed at the end of the Elektron O2 vent.
Current Elektron/ISS Status: After the spill was contained and atmospheric constituents had returned to near normal levels, the normal intermodule ventilation was restored. Toxicologists report KOH is odorless; preliminary indications are that the odor reported by the crew was organic, and likely to be due to the Elektron seal overheating. Elektron troubleshooting performed today involved inspections of the Hydrogen (H2) and Oxygen (02) outlet connectors from the [__] Elektron Liquid Unit. Both connectors were dry and clean. Subsequent troubleshooting involved purging of an H2 line with Nitrogen (N2) while covering the Oxygen line outlet with a towel and ziplock bag. Visual inspection did not show any liquid on the towel. Elektron remains deactivated at this time, and ground specialists are assessing the data to determine the next course of action. At this point in time, teams have not yet definitively determined whether the observed fluid was Potassium Hydroxide (KOH), a KOH/water solution or water alone. There is one spare [__] Elektron Liquid Unit onboard and two units in testing on the ground.
International Space Station Management Center (IMC) Daily Summary Report
Stage 12A / Flight 13S Flight Day (FD)1
09/18/06 16:00 CDT 261/21:00 GMT
[Excerpts]
New Status:
Elektron Activation Attempts: The Elektron was nominally deactivated for the 12A Docked mission. This morning, the crew was scheduled to perform Elektron activation, which included compressing the [__] Water Buffer Tank located in the un-pressurized chamber of the [__] Elektron Liquid Unit. This procedure is used often, especially after Elektron has been down for an extended period of time. Compressing the tank assists in ridding bubbles from the pumps, as the presence of bubbles will cause pump shutdown. Once compressing was complete, Elektron was activated in 32 amp mode and within two minutes failed to the backup pump, which also failed within a few minutes. After several unsuccessful reattempts at activation in both 32 and 50 amp mode throughout the morning, the Elektron was finally activated in 50 amp mode.
Elektron Overheating and Fluid Leak: Within 3 to 4 minutes from the last reactivation attempt in 50 amp mode, the crew detected an odor and an increase in temperature of one of the purification units in the [__] Elektron Liquid Unit. The crew also reported at least one of the rubber seals between the purification unit clamps where it attaches to the [__] Elektron Liquid Unit had heated to the point at which it began to smoke. The crew deactivated the Elektron at approximately 6:00 am CDT and, at request of both Mission Control Centers, manually annunciated the Service Module fire alarm. Annunciation of the fire alarm resulted in automatic activation of the ___ (Russian atmosphere scrubber), and the crew activated the Vozdukh system. The crew monitored constituents in the ISS atmosphere using the CSA-CP and kept in constant contact with ground controllers. Throughout this event, Carbon Monoxide (CO), Hydrogen Cyanide (HCN) and Hydrogen Chloride (HCL) levels were well below the thresholds at which the crew would have been required to don gas masks. Therefore, the crew was not requested to wear gas masks by either Mission Control Center. A Spacecraft Emergency was declared at approximately 6:24 am by the US Flight Control Team to allow maximum satellite coverage for communications and commanding during the initial response timeframe. The Emergency condition lasted for approximately 2 hours.
The crew also noted a liquid bubble at the end of the Elektron O2 vent (which is exposed to the internal cabin). The crew and Mission Control Centers were unable to determine the toxicity of the fluid, and therefore donned protective gear (surgical masks, gloves, and goggles) in the event that the fluid contained Potassium Hydroxide (KOH). KOH has a Level 2 Toxicity (“irritant”), and could be released from the Liquid Unit in certain failure scenarios. The crew then performed the corresponding emergency procedures to wipe up and contain the liquid bubble the crew observed at the end of the Elektron O2 vent.
Current Elektron/ISS Status: After the spill was contained and atmospheric constituents had returned to near normal levels, the normal intermodule ventilation was restored. Toxicologists report KOH is odorless; preliminary indications are that the odor reported by the crew was organic, and likely to be due to the Elektron seal overheating. Elektron troubleshooting performed today involved inspections of the Hydrogen (H2) and Oxygen (02) outlet connectors from the [__] Elektron Liquid Unit. Both connectors were dry and clean. Subsequent troubleshooting involved purging of an H2 line with Nitrogen (N2) while covering the Oxygen line outlet with a towel and ziplock bag. Visual inspection did not show any liquid on the towel. Elektron remains deactivated at this time, and ground specialists are assessing the data to determine the next course of action. At this point in time, teams have not yet definitively determined whether the observed fluid was Potassium Hydroxide (KOH), a KOH/water solution or water alone. There is one spare [__] Elektron Liquid Unit onboard and two units in testing on the ground.
