Description of Driving Event:
Potential International Space Station (ISS) Supportability Problems With Existing Extravehicular Activity (EVA) Assets
Lesson(s) Learned:
The EVA Project Office has several planned initiatives to ensure the availability of adequate EVA resources to support the ISS and Space Shuttle. These initiatives cover acquisition of material, development of procedures, and improved training.
Recommendation(s):
Expedite completion of the planned initiatives related to the safety of EVA so that maximum benefit can be realized during the upcoming intensive ISS assembly schedule.
Evidence of Recurrence Control Effectiveness:
NASA concurs with the ASAP recommendation. In June 1999, the EVA Project Office initiated the development of a small planar hard upper torso (HUT) in addition to the medium, large, and extra-large HUT's already developed. With four HUT sizes, the broadest range of crewmembers (~5th percentile Asian female to 95th percentile Caucasian male) will be accommodated. The small planar HUT has successfully completed the concept development phase, and the preliminary design review is scheduled for May 2000. The first flight item is on schedule for delivery in October 2002. Redesign of the (EMU) to allow for on-orbit replacement of a primary life support subsystem, HUT, displays and control module, and secondary oxygen pack is ahead of schedule to support the ISS 6A flight. The EVA Project Office is assessing the feasibility of flying the EMU on-orbit replacement unit configuration on ISS flight 5A prior to the need to leave an EMU onboard the ISS during 6A. Single mission certification for the phase VI glove was accomplished prior to ISS flights 2A and 2A.1. Full certification (up to 19 EVA's) was completed in March 2000, approximately 1 year prior to leaving phase VI gloves onboard the ISS for ~90-day increments. Like the phase VI glove, the U.S. Simplified Aid for EVA Rescue (SAFER) has flown with single-mission certification on five previous missions. Anomalies identified during three of these previous missions - STS-86 (failed NASA standard initiator (NSI) drive circuit), STS-88 (erroneous indication of no remaining gaseous nitrogen), and STS-96 (inadvertent NSI firing) - have all been successfully resolved through hardware redesign and/or procedures modification. A final anomaly relative to the battery gauge, which supports the requirement to remain onorbit continuously for 1 year, has been resolved, and the hardware will be certified prior to ISS flight 2A.2a (STS-101) in May 2000. Development of the Russian SAFER (RSAFER) was transferred to the RSA in April 1999 when they offered to cost share the hardware production and successfully completed the project preliminary design review. Currently, the critical design review is planned for FY 2001. One open issue to be resolved is the contractual authority to develop the RSAFER. The original plan included the RSAFER in the $35M contract modification between NASA and the RSA; however, due to congressional concerns this contract modification is currently on hold. The baseline plan to launch the RSAFER on ISS flight 7A.1 will need to be readdressed following official contract authority with the RSA. Lastly, NASA has successfully completed all of the technical and medical work necessary to implement a 2-hour EVA prebreathe protocol from a 14.7 psi atmosphere. NASA Headquarters has given approval, and plans are being developed to demonstrate the 2-hour protocol procedures (either on the ground or as part of a detailed test objective demonstration on ISS flight 5A or 6A) prior to implementation on ISS flight 7A when the joint airlock is launched. Additionally, decompression sickness contingency plans and flight rules have been developed, and crew and flight surgeon training has been initiated.
Documents Related to Lesson:
N/A
Mission Directorate(s):
- Space Operations
- Exploration Systems
Additional Key Phrase(s):
- Aerospace Safety Advisory Panel
- Extra-Vehicular Activity
- Flight Equipment
- Logistics
- Medical
- Policy & Planning
- Research & Development
- Safety & Mission Assurance
Additional Info:
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