Heat-resistant spacecraft to bring solar mysteries to light

Physicists have long had a burning desire to find out more about the sun. That opportunity is coming at last.

U researcher and physicist Keith Goetz, is working with an international team of researchers from NASA and the University of California-Berkeley to develop an unmanned spacecraft that will travel closer to the sun than any craft has before. Solar Probe Plus, a vessel about the size of a small car, will make measurements in the corona — the sun’s outermost atmosphere — that can help researchers understand how the star functions.

“Our team blends the essential science and measurement goals with instrumentation know-how to investigate the fundamental physics at work in our nearest star,” said Goetz, principal investigator for the project and program director with the U of M School of Physics and Astronomy in the College of Science and Engineering.

Among the wealth of information the spacecraft can collect, scientists hope the project will answer two specific, enduring mysteries related to the sun’s corona. The first is why the corona is actually hundreds of times hotter than the surface of the sun itself, despite being farther away. The second is to understand what process causes “solar wind” — a stream of plasma particles that continually flow out of the sun — to move at speeds faster than 1 million miles per hour.

To prepare it for the extreme temperatures nearer to the sun, the spacecraft’s heat shield will be built to survive temperatures up to 2,550 degrees Fahrenheit. The craft will reach the corona at only 4 million miles from the star’s surface.

Researchers expect to launch the spacecraft in 2018, and will continue the project at least until 2025.