Satellite Subsystems » Electrical » Solar PowerSolar PowerElectricalSatellite Subsystems

BLUEsat's power system begins with the solar panels. A panel of fourteen cells is located on each of the six sides of the satellite. The 21.5% efficiency Gallium Arsenide cells are connected in series within each panel, and each panel is separately connected to the power board. This reduces the risk of total satellite failure in the event of mechanical or electrical failure of one panel. The theoretical maximum power available from our cells in orbit is 29.19V and 0.57A. However, an average power of around 6W whilst in the sunlit portion of the orbit is more likely, due to matching and other losses. Early experiments in making our own solar panels using silicon cells were unsuccessful, though the panels which were produced gave reasonable power very cheaply. A sample panel is shown.

sample solar panel

The problem was that the encapsulating glass that was required over the top of the cells was too thick. (The glass cracked when air was removed from beneath it in prototypes using thinner glass). The cost of launching this extra glass was greater than the cost of buying some higher efficiency cells which came with a thin encapsulant on top of them. This layer provides protection from damage, mostly in the form of chemical degradation, to the cells. For these reasons, the current BLUEsat design uses 21.5% efficiency Gallium Arsenide cells purchased from Spectrolabs. These cells are soldered together and glued to a pcb which connects the cells to a positive and negative tab which then connects to the power board.

Gallium Arsenide cells purchased from Spectrolabs

The connection is made through a 6 pin flat connector (see image). Two of the pins are for the circuit supplying power, whilst the other four are for telemetry information.

solar connector

Satellite SubsystemsElectricalSolar PowerAuthor: Anthony Wicht
© The Author, the BLUEsat project or UNSW. All rights reserved.
Last Modified: May 18 2006 08:34:06.