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 highspeed 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. Highspeed computing will also be
necessary to carry out the heat transfer equations.
Progress
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.
Expected results
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.)
Team Members
Sponsoring Teachers
Project Advisor(s)