U.S. scientists say they are developing a satellite about the size of a loaf of bread that will be deployed to study space weather.

The National Science Foundation-funded project called Radio Explorer, or RAX, is being led by the University of Michigan and the SRI International Corp., a California independent research and technology development organization.

The satellite, called CubeSat, is to be the first free-flying spacecraft, and will be built, in part, by members of the university's Student Space Systems Fabrication Laboratory.

CubeSats are approximately 4-inch cube-shaped devices that launch from inside a P-Pod -- a special rocket attachment developed by California Polytechnic State University and Stanford University.

The RAX satellite will essentially be made of three CubeSats and will measure the energy flow in the Earth's ionosphere, where solar radiation turns regular atoms into charged particles.

"This project will help us better understand space weather processes, how the Earth and sun interact and how this weather produces noise in space communication signals -- noise that translates to lower quality telecommunications capabilities and error in GPS signals," said Assistant Professor James Cutler, a co-principal investigator with physicist Hasan Bahcivan of SRI.

RAX is scheduled for launch in December.