Online Journal of Space Communication


The orbital location of PowerSats plays a critical role in determining the mass of the solar power satellite (PowerSat) transmitter and the size of the rectenna on the Earth’s surface. These in turn play an important role in the cost of deploying the PowerSat, especially the cost of launching the PowerSat into orbit as the transmitter makes up a large part of the PowerSats mass. We will consider a new approach to PowerSat orbital positioning by considering a circular sun-synchronous orbit at 5,185.3 kilometers with an inclination of 142.1 degrees. Locating the PowerSat at this location offers several benefits and only one major drawback. The benefits include small transmitter, small ground rectenna, small minimum power levels, constant energy production and constant energy delivery.

The one drawback in that this location is in the inner Van Allen radiation belt, which is a high radiation environment. Locating the PowerSat in the radiation belt is problematic as the radiation can damage the solar cells. However, the use of highly concentrated solar energy can potentially be used to heal the damaged solar cells, thereby providing a reasonable solution to the problem of radiation damage. Ideally the use of highly concentrated solar energy would be used in the design of the PowerSat anyway to reduce the mass to orbit requirements.

By placing the PowerSat constellation in a medium Earth orbit (MEO) that is sun-synchronous the constellation can provide continuous power to specific sites on the ground. However, SPS in this orbit, which is the most intense region of the Earth’s Van Allen radiation belt, would require dramatic advances in radiation hardening for all systems. Solar arrays, in particular have been found to be susceptible to degradation due to exposure to radiation. Self-regeneration of solar cells using heat has already been demonstrated at the experimental stage and the high heat level available at 2,000 suns solar concentration should be sufficient to heal the cells. Concentrated solar energy can potentially reduce PowerSat energy production system mass by an order of magnitude (90%). This combined with a close orbit which can reduce transmitter mass by an order of magnitude (90%), will allow for the development and deployment of much smaller, more mass efficient PowerSats. In addition to these advantages the PowerSats will also have a much lower minimum power level which means that much smaller systems can be deployed incrementally rather than building massive PowerSats as has been proposed in the past. This paper and accompanying visualization will discuss the benefits of combining concentrated solar energy at 2,000 suns concentration with an MEO sun-synchronous orbit at 5,185.3 kilometers with an inclination of 142.1 degrees to achieve a low mass PowerSat and how to overcome the problem of a high radiation environment by taking advantage of the solar energy available to periodically heal the solar cells.

Click here to see the video: Concentrated Solar in Sun-Synchronous Orbit - 2014 SunSat Design Competition



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