The Space Academy sat down to lunch with guest speaker Dr. Sheila Bailey on Wednesday, August 3rd in a conference room at GRC. Dr. Bailey has been a lecturer and teacher since 1975 at various a academic institutions. She has been a NASA employee since 1985 and currently serves as both researcher at Glenn Research Center and president of the Employees Union.
She was responsible for starting the photo luminescence lab, nanocharacterization lab, spectrometry lab, and scanning electron microscope lab at Glenn Research Center. Her job description simply has the vague mandate of “make a better solar cell.” This could have different meanings to different people. Does a better solar cell improve the rating at the beginning or the end of the life cycle? A solar cell for terrestrial use would not necessarily be the better for use in space.
Bell laboratory invented the first solar cell. Much like the transistor, it was initially thought to be a novelty, too expensive for real applications. However, the need for a light-weight, long-term energy system was later obvious for satellite applications. For this sort of use, the cost of a solar cell is minimal in comparison to launch and design costs.
These first solar cells were about 6% efficient. The efficiency of the art solar cells during space station construction was approximately 14.2%. Currently, technology has progressed to nearly 20% efficiency with a maximum theoretical goal of 33%.
Solar cells for space use must be more rugged against radiation and charged particles from the sun (normally filtered out by the earth’s magnetic field), which tend to degrade the panels. The silicon panels used on the ground and initially used in space tend to degrade horribly. For this reason, a lot of effort has been put in to group 3,5 solar cell technology.
Before her career began at NASA Glenn Research Center, Sheila lived a very interesting life. For example, she drove from Liverpool to Capetown and partway back before finding out she was pregnant in Nyobi when she immediately flew home to North Carolina.