| Budget Amount *help |
¥15,300,000 (Direct Cost: ¥15,300,000)
Fiscal Year 2006: ¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2004: ¥9,400,000 (Direct Cost: ¥9,400,000)
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| Research Abstract |
This research has investigated the correlation between impact features on a solar cell and physical properties of a particle impacted, by hitting the solar cell on an aluminum honeycomb panel with CFRP face sheets, with an aluminum alloy ball of 1/8 inches in diameter at a velocity range below 800 m/sec. As a result, the size, the angle of incidence, and the impact speed of the particle can be estimated according to the following procedures :
1)The impact speed of the particle can be estimated from the number of cracks around the crater/hole on the cover glass of the impacted solar cell.
2)The ratio of the damaged area to the cross-sectional area of the particle can be estimated from the above-estimated impact speed.
3)The size of the particle can be estimated from the ratio of the damaged area to the cross-sectional area of the particle and the length of the minor axis of the elliptic crater/hole on the solar cell.
4)The angle of incidence of the particle can be estimated from the length
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of major and minor axes of the elliptic crater/hole on the solar cell.
If an optical camera is mounted somewhere on the main body of the satellite, on the other hand, its field of view is expected narrow not enough for observing the solar paddle efficiently. To assist the observation with the camera, the use of acoustic emission (AE) sensors to identify the particle impact position and time was examined. The impact tests were conducted to the aluminum honeycomb panel with CFRP face sheets, and two AE sensors installed on the panel with a distance of 330 mm were used to identify the particle impact position. The estimation error was smaller than 19 mm with respect to the distance between the two AE sensors and was small enough to identify the impacted solar cell.
The aforementioned results have validated the observation system combined with AE sensors to identify the solar cell impacted, and an optical camera to acquire the impact features. Moreover, we have suggested two design strategies; 1) an optical camera mounted somewhere on the main satellite and AE sensors attached somewhere on a solar array paddle, or 2) both an optical camera and AE sensors installed somewhere on the solar array paddle. Less
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