Solar Probe Plus is a project that astronauts, scientists, meteorologists, and astronomers have been dreaming of for a half-century. It's an extraordinary proposal, venturing eight times farther than any previous spacecraft. It will certainly cost more than one billion dollars, and requires engineering and technology that's never been seen before.
All this for a one-way trip to the sun.
Solar Probe Plus is the name of a project in which an unmanned (obviously), lightweight probe will travel through the sun's corona, which is essentially the sun's outer atmosphere. It seeks to answer some of space's most puzzling questions--why is the corona almost 200 times hotter than the sun's actual surface? How does the sun create the solar wind, a stream of charged particles that engulfs the solar system in a vast bubble called the heliosphere?
These are basic questions about our own solar system that have so far been unanswerable due to budgetary and technical limitations--but not anymore.
One of the most obvious problems is the immense heat the probe must be able to withstand. That the probe must tolerate heat at 2,600 degrees Fahrenheit is bad enough, but NASA won't even be able to use the same methods used for probes returning to Earth. In those probes, the outer heat shields "ablate," or boil away harmlessly--but when the whole point is to carefully conduct particle detection and other measurement, you can't have part of a dissolved shield mucking up the findings.
But NASA scientists are confident that they'll be able to create a suitable probe by 2018, the prospective launch date. Solar Probe Plus will arrive at Venus eight weeks after liftoff, conduct 24 orbits of increasing size, and end up about four million miles from the sun--inside Mercury's orbit, eight times closer to the sun than any previous mission.
Though much of the motivation for Solar Probe Plus is research, there actually are a few legitimate practical reasons to undertake such a mission. Says Discovery:
Solar storms and magnetic disturbances from the sun can disrupt satellites and radio transmission, as well as take out power grids on Earth.
"Right now, predicting space weather is kind of like trying to predict hurricanes without knowing the acceleration effects of the oceans. Without that, you really can't understand them at all," Dantzler said.
NASA is expected to make final decisions on the probe's instruments and sensors this month.