Analysis of the UNISAT-3 Solar Array In-Orbit Performance

Abstract

A technological experiment to assess the in-orbit performance of non-space-rated solar arrays is onboard the microsatellite UNISAT-3. These include terrestrial-technology monocrystalline silicon and low-efficiency triplejunction solar arrays, assembled using commercial off-the-shelf materials and following conventional non-spacerated procedures. A space-rated monocrystalline silicon solar array is also onboard, used for comparison of the achieved results. The manufacturing process is described and the solar array performance is evaluated based on the data collected in the first two-and-a-half years of operation in orbit. For both terrestrial-technology and lowefficiency triple-junction solar arrays, the observed solar array degradation is very fast in the first half-year, in which approximately one-fourth of the initial efficiency is lost. Then degradation stabilizes, showing a long-term decaying rate with a time constant of ten years, which makes the suggested technology suitable for small scientific and educational low-Earth-orbit spacecraft.

Attitude determination of planetary exploration rovers using solar panels characteristics and accelerometer

“…In this case, the model [14] is different from that used in this study. It is necessary to use an adequate and appropriate model depending on the type of solar cells.…”

“…In the other hands, radiation is much affects the characteristics of solar cells. In the UNISAT-3 mission the observed solar array degradation was very fast in the first half-year, during which approximately one-fourth of the initial efficiency was lost [14]. Although this type of degradation should be considered when the attitude is estimated using the current of the solar panels in actual space exploration missions, it is ignored here because the experiments were conducted on the earth.…”

Passive magnetic attitude stabilization system of the EduSAT microsatellite

“…The single rod volume is about 2 × 10 −7 m 3 . The arrangement of many parallel rods on the satellite produces a mutual demagnetizing effect, which can be neglected when the rods are suitably located [6,11]. The best configuration is to arrange the rods in the plane perpendicular to the permanent magnet axis, passing through its centre.…”

LEO Object’s Light-Curve Acquisition System and Their Inversion for Attitude Reconstruction

“…In recent years, the Sapienza Space System and Space Surveillance (S5Lab) gained experience in satellite systems manufacturing and launches, and in the space debris field [8][9][10][11][12][13][14][15][16][17][18], operating networks [19][20][21][22][23][24][25] of completely remote optical observatories, which are able to observe, catalogue and identify a huge number of objects both known that unknown, thanks to which it was possible to refine the correlation between light curves and attitude dynamics of the observed debris. For these reasons, every methodology discussed in this paper is strongly based on a great number of observations, which makes it possible to obtain reliable and solid results.…”