Parker Solar Probe
An illustration of NASA's Parker Solar Probe, previously known as Solar Probe Plus, en route to the sun. Credit: NASA/JHUAPL

WASHINGTON — NASA’s Solar Probe Plus mission, scheduled for launch next year to travel closer to the sun than any previous spacecraft, has a new name honoring a scientist who predicted the existence of the solar wind.

In a ceremony at the University of Chicago May 31, NASA announced that the spacecraft will now be called the Parker Solar Probe after Eugene Parker, a professor emeritus in the university’s astronomy and astrophysics department.

The name represents a twist on an agency tradition. “NASA has named about 20 spacecraft after distinguished researchers,” said Thomas Zurbuchen, NASA associate administrator for science, at the ceremony. That includes major space telescopes like Hubble, Chandra and Spitzer, as well as smaller missions like Fermi.

“However, NASA has never named a spacecraft after a researcher during their lifetime,” he added. The Parker Space Probe will be the first such mission.

Parker, as a young scientist at the university in 1958, predicted that the sun emitted a stream of high-velocity particles, now known as the solar wind. “This was really a transformative idea at the time,” said Eric Isaacs, executive vice president for research, innovation and national laboratories at the university. Parker, in fact, struggled to get a paper about the solar wind published because many other scientists were skeptical about his findings.

Within a few years, however, spacecraft missions confirmed the existence of the solar wind, as well as the shape of the sun’s magnetic field that he also predicted. “It made this a huge home run and really one of the biggest discoveries, I think, in solar or space physics,” Zurbuchen said.

Many aspects of solar activity, though, remain a mystery, including the mechanism that heats the sun’s corona to temperatures of millions of degrees. Helping unravel those mysteries will be the primary mission of the Parker Solar Probe.

Work on the spacecraft remains on track, project scientist Nicola Fox said at the event. The spacecraft, being built by the Johns Hopkins University Applied Physics Laboratory, will move to NASA’s Goddard Space Flight Center late this year for environmental testing.

The spacecraft is scheduled for launch during a 20-day window that opens at the end of July 2018. A Delta 4 Heavy, equipped with an additional third stage, will launch the spacecraft, and seven Venus flybys over seven years will put the spacecraft into an orbit that brings it to within six million kilometers of the sun’s photosphere on its closest approach.

On those close approaches, the spacecraft will be protected by a heat shield made of carbon composite material more than 11 centimeters thick. The heat shield will keep the spacecraft at roughly room temperature while the shield is exposed to conditions approaching 1,400 degrees Celsius.

Parker, who turns 90 on June 10, also received NASA’s Distinguished Public Service Medal at the ceremony. “I’m certainly greatly honored to be associated with such a heroic scientific space mission,” he said.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...