AXAF low intensity-low temperature (LILT) testing of the development verification test (DVT) solar panel

Conference · Wed Jul 01 04:00:00 EDT 1998

OSTI ID:20000331

Alexander, D; Edge, T; Willowby, D

The planned orbit of the Advanced X-ray Astrophysics Facility (AXAF) spacecraft will subject the spacecraft to both short (less than 30 minutes for solar and less than 2 hours for lunar) and long earth eclipses and lunar eclipses with combined conjunctive duration of up to 3 to 4 hours. Lack of proper Electrical Power System (EPS) conditioning prior to eclipse may cause loss of mission. To avoid this problem, for short eclipses, it is necessary to off-point the solar array prior to or at the beginning of the eclipse to reduce the battery state of charge. This yields less overcharge during the high charge currents at sun entry. For long lunar eclipses, solar array pointing and load scheduling must be tailored for the profile of the eclipse. The battery state of charge, loads, and solar array current-voltage (I-V) characteristic curves must be known or predictable to maintain the bus voltage within acceptable range. To address engineering concerns about the electrical performance of the AXAF solar array under penumbral Low Intensity and Low Temperature (LILT) conditions, Marshall Space Flight Center (MSFC) engineers undertook special testing of the AXAF Development Verification Test (DVT) solar panel in September-November 1997. In the test the DVT test panel was installed in a thermal vacuum chamber with a large view window with a mechanical flapper door. The DVT test panel was flash tested with a Large Area Pulsed Solar Simulator (LAPSS) at various fractional sun intensities and panel (solar cell) temperatures. The testing was unique with regards to the large size of the test article and type of testing performed. The test setup and results will be presented.

• Research Organization: NASA, Marshall Space Flight Center, AL (US)
• OSTI ID: 20000331
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
BATTERY CHARGE STATE
ELECTRIC BATTERIES
ORIENTATION
PERFORMANCE TESTING
POWER CONDITIONING CIRCUITS
SOLAR CELL ARRAYS
SPACECRAFT POWER SUPPLIES
TEST FACILITIES