{"id":39851,"date":"2013-05-15T18:04:07","date_gmt":"2013-05-15T10:04:07","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/no-return-of-the-leak-iss-teams-clear-concern-as-false-signature\/"},"modified":"2013-05-15T18:04:07","modified_gmt":"2013-05-15T10:04:07","slug":"no-return-of-the-leak-iss-teams-clear-concern-as-false-signature","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/no-return-of-the-leak-iss-teams-clear-concern-as-false-signature\/","title":{"rendered":"No return of the leak \u2013 ISS teams clear concern as false signature"},"content":{"rendered":"

The International Station Station (ISS) team have confirmed they still have an air tight cooling system on the P6 Truss Photo Voltaic Thermal Control System (PVTCS), following the observation of leak indications during the recent Soyuz TMA-07M undocking. The indications were blamed on a lack of data on the entire system, as the ISS maneuvered for the departure of the Russian vehicle.<\/p>\n<\/p>\n

Recent Ammonia Leak:<\/p>\n

Following recent events, the ISS controllers are continuing to keep a very close eye on the system that uses ammonia to dissipate heat from the electrical power systems on the truss.<\/p>\n

The system leaked last week, when controllers observed data that indicated a large increase in a previously known small ammonia leak in the cooling loop of power channel 2B. At the same time, the crew inside the station noted that they were able to see flakes of ammonia originating from the channel 2B area, which were floating away into space.<\/p>\n

\"MarshburnConfirmation of a serious leak ultimately resulted in both the teams on the ground and in space to spring into action, resulting in an unplanned EVA taking place less than two days after the leak was spotted.<\/p>\n

Spacewalkers Chris Cassidy and Tom Marshburn ventured out of the Quest Airlock on Saturday, successfully inspecting the hardware, before swapping out the old 2B Pump Flow Control Subassembly (PFCS) with one of the two spares located on the truss.<\/p>\n

With the system recharged, controllers successfully returned the flow of ammonia without any anomalous indications, allowing the spacewalking duo to return back inside the ISS an hour ahead of schedule.<\/p>\n

Marshburn then prepared for his return back to Earth onboard Soyuz TMA-07M, along with departing Expedition 35 commander Chris Hadfield and Russian cosmonaut Roman Romanenko. They successfully landed on the steppe of Kazakhstan, southeast of Dzhezkazgan on Monday.<\/p>\n

Leak Returns?<\/p>\n

However, controllers noticed an issue during the period surrounding the departure of the Soyuz, which appeared to indicate the ammonia leak on the 2B system had returned.<\/p>\n

\"PVTCS\u201cPost the Soyuz undock, there were several indications that the gross 2B PVTCS leak was still present. The 2B PVTCS was shutdown to preserve consumables as the team continues to monitor the system,\u201d noted a flash on L2\u2019s rolling ISS Update Section.<\/p>\n

\u201cThe channel 2B primary power equipment has powered down to a dormant configuration. Channel 2A continues to power all downstream loads of channel 2B.\u201d<\/p>\n

Controllers positioned cameras on the ISS to take a closer look, in order to see if they could spot ammonia flakes departing from the region. No such observations were seen.<\/p>\n

With evaluations taking place on the ground, the focus switched to a possible false signature indication on the system, which was immediately backed up by the ISS\u2019 requirement of maneuvering to different attitudes to cater for the Soyuz\u2019s departure.<\/p>\n

\"ISS\u201cAs a result of the PVTCS troubleshooting performed on EVA 20 in November, the modified 2B loop includes four separate accumulators as compared to one accumulator in the unmodified system,\u201d added notes.<\/p>\n

\u201cDuring the Soyuz undock, telemetry was only available for a single accumulator. After the maneuver to the undocking attitude, the quantity reading of that accumulator began dropping.\u201d<\/p>\n

As part of the written response plans, the pump was shut down and the power was removed from the 2B power channels.<\/p>\n

Once the ISS was back into its regular attitude, additional data became available that showed the quantity in the other accumulators had actually been increasing or remaining stable while the one accumulator had been decreasing. This backed up the theory the ammonia fluid was shifting through the system, as opposed to leaking \u2013 a theory supported by the absence of snowflakes seen with the earlier leak.<\/p>\n

See Also<\/h4>\n