Search Results

EMU hardware processing, the refurbishment and checkout subset of EMU ground turn-around activities between Shuttle flights, is significantly lower today than it was when EMUs began regular service aboard Shuttle. Despite a significant increase in safety checkout steps resulting from the Challenger accident, hands-on processing time has dropped from approximately 4,000 manhours per EMU then to approximately 1,050 manhours now. The following aspects of hardware maturity contribute to this reduction: EMU hardware problems have been identified and fixed. Flight hardware and ground test rigs were designed or modified to simplify testing, and test procedures were standardized and streamlined. Increased confidence in the hardware allows extension of inspection, service and test intervals. The hardware processing sequence has recently been simplified and implementation is expected to reduce EMU hardware processing time to approximately 600 manhours/EMU in the near future.

The Space Shuttle Program Extravehicular Mobility Unit (SSP EMU) will support initial phases of the Space Station Freedom program. These phases are station assembly and man-tended operation from Shuttle and the first stages of Station's permanently manned capability. Station support increases requirements for on-orbit duration, adds new requirements for accommodation aboard Freedom and adds new environments unique to Freedom. Building upon enhancements currently in the EMU program, the SSP EMU appears to be well capable of meeting these new requirements. Certification will be extended by analysis and test and supported by limited redesign in a few specific areas. This paper discusses the enhanced EMU, identifies the new requirements for Space Station Freedom support, the process for identifying and approving these requirements, and the expected delta certification and limited redesign programs.

Shuttle Extravehicular Mobility Unit (EMU) studies have shown that the thermal interaction between the crewperson, liquid cooling garment and EMU thermal management system is highly transient in nature. Recent investigations of these phenomena provide a better understanding which have helped improve thermal comfort in the present system. Analyses show that the key to thermal comfort is understanding the interaction between physiological responses and EMU system thermal transients. A test program was conducted to evaluate the theorized causes of discomfort and proposed corrective actions. Several EMU thermal management related modifications were utilized in the Hubble Space Telescope repair mission where five, two crewperson ExtraVehicular Activities (EVAs) were conducted without any thermal discomfort in a mildly cold environment.