Accelerated mission simulation test for AXAF-I

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:186999

Brewer, J C; Jackson, L G ^[1]; Lurie, C; Foroozan, S ^[2]

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1. NASA, Huntsville, AL (United States). Marshall Space Flight Center
2. TRW, Redondo Beach, CA (United States)

The mission profile for the Advanced X-ray Astrophysics Facility -- Imaging (AXAF-I) vehicle is characterized by long solstice seasons and short eclipse seasons. This type of cycle profile is ideal for accelerating real-time testing by shortening the solstice seasons while maintaining real-time cycling during eclipse seasons. Because of the benign operation of the nickel-hydrogen (Ni-H{sub 2}) cells during the solstice seasons, this acceleration can be done without significantly decreasing the validity of the test results. For AXAF-I, this acceleration technique allows an analysis of ``end-of-mission`` data after only 1 year of testing. The accelerated testing profile is used here on a five-cell pack of AXAF-I flight-design 30 ampere-hour (Ah) Ni-H{sub 2} cells. It will be used to verify that the proposed design is capable of meeting mission life requirements. Since these cells were built, the capacity planned for the flight cell has been increased to 40 Ah. The design, however, remains identical to that of this 30 Ah cell. The test began in March 1994 and will be completed in the early summer of 1995. Preliminary results from this test indicate acceptable performance of the cells during the first half of the mission simulation. Acceptance test data at TRW and at the Marshall Space Flight Center (MSFC) show extremely tight voltage and capacity performance -- both well above minimum specification values. This tightly-grouped voltage performance has been maintained during the mission simulation portion of the test. Estimated capacities (based on pressure) also continue to be well above minimum requirements, although verification of these estimates through a capacity test is not planned until the mission simulation is completed.

• OSTI ID: 186999
• Report Number(s): CONF-950729--
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
ELECTRIC POTENTIAL
EXPERIMENTAL DATA
NICKEL-HYDROGEN BATTERIES
PERFORMANCE TESTING
SPACECRAFT POWER SUPPLIES
SPECIFICATIONS