NASA has selected which scientific experiments will fly on the Solar Probe Plus spacecraft bound for the sun’s outer corona in 2018, where temperatures reach millions of degrees Fahrenheit. Given the 88 pound weight limit, there was only enough room for five experiments. And all the experiments have a power budget of only 40 watts (about the same as your refrigerator light). One which made the cut will measure the electrons, protons and helium ions present in the solar wind. Another will take digital, 3D images of the sun’s corona.
What’s the Big Idea?
The sun’s corona, most visible during a solar eclipse, extends millions of miles away from the sun’s surface. And after being looped around Venus, the Solar Probe Plus craft will approach the sun within 3.7 million miles, much closer than any mission before. The mission asks two central questions: “How does the corona, that ghostly, spiked halo seen during a total solar eclipse, heat to more than a million degrees, far hotter than the sun’s surface? And what powers the solar wind, the stream of charged particles that flows from the corona?”