{"id":41162,"date":"2009-03-13T01:38:49","date_gmt":"2009-03-12T17:38:49","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/red-threshold-late-notice-conjunction-threat-misses-iss-crew-egress-soyuz\/"},"modified":"2009-03-13T01:38:49","modified_gmt":"2009-03-12T17:38:49","slug":"red-threshold-late-notice-conjunction-threat-misses-iss-crew-egress-soyuz","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/red-threshold-late-notice-conjunction-threat-misses-iss-crew-egress-soyuz\/","title":{"rendered":"RED threshold late notice conjunction threat misses ISS \u2013 Crew egress Soyuz"},"content":{"rendered":"

The three members of Expedition 18 carried out the contingency of  \u201cevacuation\u201d into the Soyuz spacecraft attached to the International Space Station (ISS), following a \u201cRED threshold late notice conjunction threat\u201d alert, related to Object \u201c25090 PAM-D\u201d debris. The threat passed with no impact, allowing the crew to egress back into the Station.<\/p>\n

\nTracking of the small piece of debris\/MMOD (Micrometeoroid Orbital Debris) was initially classed as a low threat of collision with the ISS. However, latest tracking suggests the threat is red.As a contingency, NASA\u2019s Expedition 18 Commander Mike Fincke, Russian Flight Engineer Yury Lonchakov, and NASA\u2019s Sandra Magnus were asked to \u201cevacuate\u201d into the Russian Soyuz, which would serve as their means of departing from the Station \u2013 had it been required.<\/p>\n

The debris object is called a \u201cyo weight\u201d \u2013 which was originally part of a Delta PAM-D stage \u2013 used to launch GPS 37 in 1993. The yo weight is a small mass attached to a 1-meter-long cable, used to tumble the stage after separation from the payload so it doesn\u2019t recontact. Although it would have a mass less than 1kg, travelling at 17,500 mph makes even the smallest object a serious threat.<\/p>\n

Updating the current status of the threat, several memos \u2013 acquired by L2 \u2013 relay the probability level of the conjunction, with the latest noting \u201cIt\u2019s now in the red threshold and if it doesn\u2019t improve between now and TCA (Time of Closest Approach) at 11:39am CDT today they will put the crew in the Soyuz per the rules.\u201d<\/p>\n

\"a111\"\u201cThe plan that has been coordinated with MCC-M (Moscow) is that if required the crew will enter the Soyuz and be in place by 16:35 staying there until at least 5 minutes post TCA,\u201d added another memo. <\/p>\n

\u201cWE will not be closing any additional hatches to enable us to immediately run the nominal depress procedures should they be needed.<\/p>\n

\u201cIf the PC remains red the course of action will be to place the crew in the Soyuz from 5 minutes before TCA until 5 minutes after TCA.  This is ~2 hours after crew post sleep activities (crew will be awake). \u201c<\/p>\n

Update at 11am Central: Crew now closing the hatches and preparing to evac to Soyuz as a contingency in case of debris collision with ISS. Now in Soyuz.<\/p>\n

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Post Conjunction update: Debris passed by the ISS without impact, allowing the crew to egress Soyuz to re-open the hatches and continue with their tasks.<\/p>\n

Background:<\/p>\n

The opening notification memos appeared to show the threat was low, even though tracking was expected to show the \u201cmiss distance\u201d would reduce as the numbers were refined.<\/p>\n

\u201cReceived a low concern, late notification (42 hours to TCA) conjunction for a small piece of PAM-D debris,\u201d noted the opening memo relating to the threat. \u201cThis object showed good tracking and a miss outside the notification box. Subsequent updates showed miss distances to increase until the latest update.<\/p>\n<\/p>\n

See Also<\/h4>\n