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Freitag, 28. April 2017 - 07:30 Uhr

Raumfahrt - NASA-Verwaltung ist besorgt über Extravehicular Mobility Unit (EWU) Raumanzüge der Internationalen Raumstation (ISS)

28.04.2017

Space Station Spacesuits Suffer After Shuttle Shutdown

NASA's Office of Inspector General (OIG) released a report today assessing NASA's management of its existing spacesuits and development of new models.  It expressed concern about Extravehicular Mobility Unit (EMU) spacesuits used on the International Space Station (ISS) for extravehicular activity (EVAs, or spacewalks, which cannot be returned to Earth easily for maintenance following termination of the space shuttle program.  As for new spacesuits, NASA Headquarters was criticized for continuing one contract for 5 years after Johnson Space Center recommended its termination.  Overall, the OIG is concerned whether NASA will have the spacesuits it needs in the next decade.

For the space shuttle program, 18 EMUs were produced.  Eleven are still available, but their design assumed they would be returned to Earth with every space shuttle mission and routinely serviced.   After the shuttle was terminated in 2011, however, the only way to bring them back is on SpaceX Dragon spacecraft, the only space station cargo vehicle designed to survive reentry.  (Russia's Soyuz spacecraft, which ferries crews, also survives reentry, but there is no extra room for empty spacesuits needing repair.)

Since the ISS was first occupied in 2000, NASA has allowed the required ground maintenance interval to grow from one year to six years or 25 spacewalks, whichever comes first.


Snip from page 15 NASA Office of Inspector General (OIG) report IG-17-018, NASA's Management and Development of Spacesuits, April 2017.

The age and condition of the U.S. spacesuits hit the headlines in 2013 when European Space Agency (ESA) astronaut Luca Parmitano almost drowned when water collected inside his helmet during a spacewalk (EVA 23) due to a blocked filter.  The OIG report revealed that was one of 19 "significant incidents" with spacesuits in the space station era (2000 to today), five of which involved water.  A total of 156 U.S. spacewalks were conducted during that period of time.  All five of the space-station-era water events occurred since 2010.  Parmitano's EVA 23 and two others (EVA 22, also in 2013, and EVA 35 in 2016) involved water intrusion into the helmet.  The others were condensation/fog.


Snip from page 11 NASA Office of Inspector General (OIG) report IG-17-018, NASA's Management and Development of Spacesuits, April 2017. 

Of the 18 original spacesuits, five were destroyed during missions (two on Challenger, two on Columbia, and one on the SpaceX CRS-7 failure) and one during ground testing in 1980.  Another was a ground certification unit only.  That leaves 11 -- four on the ISS and the rest on Earth "in various stages of refurbishment and maintenance." 

With the cadence of EVAs NASA is planning for the next several years, plus the possibility of unplanned EVAs that might be required, the OIG report concludes that NASA "will be challenged to continue to support the EVA needs of the ISS with the current fleet of EMUs through 2024 -- a challenge that will escalate significantly if Station operations are extended to 2028." 

NASA has been funding development of new spacesuits for the past decade, though not for use on ISS.   Plans to send crews beyond LEO, where ISS is located, for the first time since the Apollo missions means new spacesuits are needed for exploration of that environment.  The OIG calculates that since 2007 NASA has spent almost $200 million on three such efforts:  the Constellation Space Suit System (CSSS) for the Bush-era Constellation program ($135.6 million), the Advanced Space Suit Project managed by NASA's Advanced Exploration Systems office ($51.6 million), and the Orion Crew Survival System or OCSS ($12 million).  OCSS is being designed for launch, entry and abort, not spacewalks.

"Despite this investment, the Agency remains years away from having a flight-ready spacesuit capable of replacing the EMU or suitable for EVA use on future exploration missions."  Given the current schedule "there is significant risk a next-generation prototype will not be sufficiently mature in time for testing on the ISS" prior to 2024.  

The United States and the other ISS partners -- Russia, Japan, Canada and 11 European countries working through ESA -- have agreed to operate ISS until then, although some NASA and other U.S. officials express hope that it could be extended at least until 2028, 30 years after the first modules were launched. 

The OIG was especially critical of a NASA Headquarters (HQ) decision to continue funding the CSSS contract after 2011 when Johnson Space Center (JSC) recommended it be terminated following cancellation of the Constellation program.  NASA HQ continued to fund it for 5 more years rather than redirecting that money, $80.8 million over that time period, to the Advanced Space Suit Project. That project has struggled in recent years both in terms of getting funding and determining its scope.

As for development of the OCSS Orion survival spacesuit, the OIG worries that there is little schedule margin if NASA accelerates Exploration Mission-2 (EM-2) to 2021.  EM-2 is currently on the books as the first Orion mission to carry a crew.  (NASA is studying whether to put a crew on the first mission, EM-1, but no decision has been made.)  Officially EM-2 is scheduled for 2023, but NASA is trying to move that date up to August 2021.   Right now, the OCSS will not be ready until March 2021, just 5 months earlier. 

The report made three recommendations to NASA: develop and implement a formal plan for design, production and testing of next-generation EVA spacesuits; conduct a trade study of the cost of maintaining the existing space station EMU spacesuits versus developing a new version; and apply lessons learned from operating existing spacesuits to the design of the next-generation models.  

NASA management concurred with those recommendations, but disagreed with the OIG's assessment of the value that was returned from the CSSS contract arguing that they got their money's worth.  The OIG did not relent, ending the report by restating that the extra 5 years of funding "did not serve the best interests of the Agency's spacesuit development efforts."

Quelle: SPACEPOLICY


Tags: Extravehicular Mobility Unit (EWU) 

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