Why Solar Power

For the Planar Robots to work on planets, it must have sufficient and continuous energy supply. For daytime, the best and reasonable source of this energy must be the Sun. The energy supply from the Sun is truly enormous: For example, on average, the Mars's surface receives about 590 W per Mç°¡ of solar radiation. And, photovoltaic power generation is reliable, involves no moving parts, and the operation and maintenance costs are very low. The operation of a photovoltaic system is silent, and creates no atmospheric pollution on the planets. Photovoltaic systems are modular, and can be quickly installed. Power can be generated where it is required without the need for transmission lines.

Solar Cell Operation on Mars

Let us take Mars as a location for our initial implementation of the rover system. The environment of Mars affects the selection of solar cells for surface operation. The surface of Mars has an environment significantly different from the Earth. Solar cell performance is the major constraint on the landing site latitude, on science operations, and on how long during each day and during which Mars seasons a spacecraft can operate.

The Mars environment is different in several critical ways from the orbital environment in which space solar arrays normally operate. There are a few points that we should consider on the Mars.

1. Solar intensity and spectrum modified by dust
2. Indirect sunlight
3. Low temperature operation
4. Deposited dust
5. Radiation environment different from Earth orbit
6. Atmospheric pressure

Solar intensity and spectrum modified by dust

Fig 1: The Martian landscape, in particular the light colour of the sky, showing the scattering of light by suspended dust particles.