Challenge Team Interim Report
Team Number: 058
School Name: Pecos High School
Area of Science: Environmental Sciences
Project Title: The Effect of Solar Power Satellites on Surface Ground Temperature
Definition of the problem
As the population of the Earth increases, supplying enough energy will soon become a major problem. Due to this increase of the demand for energy, new power sources have to be found. One of the possibilities is the Solar Power Satellites (SPS). That's the idea of installing huge solar panels in space. The SPS converts sunlight into electrical energy and transmits it via microwaves to Earth, where it is converted back into electricity.
My question is, if huge satellites around the earth will have an effect on the earth's surface temperature and how.
Computation / Approach
To answer this question I will write a program that will calculate the surface temperature with the size and altitude of the satellite as variables.
There are four steps necessary to solve this problem:
1. Calculating the size of the umbra and penumbra of the shadow.
2. Calculating the amount of diffraction occurring at the side of the satellite and its effect on the shadow.
3. Calculating the amount of refraction occurring in the earth's atmosphere.
4. Making a model of the heat flow on the soil's surface.
A high-speed computer would be necessary to run the final program. It would use statistical averaging rather than ray tracing to determine the amount of shadow cast by the SPS. High-speed computing will also be necessary to carry out the heat transfer equations.
Most the research is completed. Unfortunately there are limited resources available on this subject. I have contacted several people from Switzerland and Los Alamos National Labs. I also started to develop some of the formulas necessary to calculate the umbral area of the shadow.
The final results will be a series of time lapsed 2D images showing the flow of heat from the warmer surrounding ground to the shadowed area. If I assume that the satellite is on an altitude of 40,000 km (geo synchronous orbit) and that the sun subtends an angle of 0.5 degrees, the satellite has to be 349 km in diameter in order to completely block out the sun. (This doesn't include penumbra, refraction etc.)