2017-05-31 18:56:02
Newly Named NASA Spacecraft Will Aim Straight for the Sun

18:56, May 31 53 0

Last week, NASA teased that it would have an announcement about next year’s mission to send a spacecraft into the outer atmosphere of the sun. Commenters on Twitter joked that the space agency might be sending humans there.

The actual news? The spacecraft remains the same, but it has a new name.

The Solar Probe Plus spacecraft is now the Parker Solar Probe, named after Eugene N. Parker, the astrophysicist who predicted the supersonic solar wind — a barrage of charged particles ejected by the sun at more than a million miles per hour.

About 20 spacecraft have been named after prominent scientists, including Edwin Hubble, Lyman Spitzer Jr., Subrahmanyan Chandrasekhar and Enrico Fermi, but this is the first time that a NASA mission carries the name of a living scientist.

“It is my great honor, a few days before your 90th birthday, Gene, to announce we are renaming the Solar Probe Plus spacecraft,” Thomas Zurbuchen, associate administrator for NASA’s science mission directorate, said Wednesday at a ceremony at the University of Chicago, where Dr. Parker is an emeritus professor of astronomy and astrophysics.

The spacecraft, now being built and tested, is to launch next year on an elliptical trajectory that will take it within the orbit of Mercury. Repeated flybys of Venus will act as a gravitational brake to bring it closer to the sun, and it will eventually dive within four million miles of the sun’s surface, while accelerating to 430,000 miles per hour. That will make it, by far, the fastest human-made object ever.

“I’m greatly honored to be associated with this heroic scientific mission,” Dr. Parker said.

He predicted the existence of the solar wind in 1958. The idea was outlandish, and referees of the paper at The Astrophysical Journal initially rejected it. At the time, the region between planets was regarded as boring empty space. Dr. Parker instead described complex interactions between speeding charged particles and buffeted magnetic fields.

“It was a fundamental insight that forever changed the way in which we understand the sun, the heliosphere and in general interplanetary space,” said Eric D. Isaacs, the executive vice president for research at the University of Chicago.

In 1962, NASA’s Mariner 2 spacecraft, en route to Venus, confirmed Dr. Parker’s solar wind predictions.

More than half a century of observations since then have filled in many details, but a core mystery remains: How does the sun generate the solar wind? That mystery hinges on the heating of the sun’s atmosphere.

The surface of a sun is a toasty 10,000 degrees Fahrenheit. About 1,300 miles above the surface, temperatures in the sun’s atmosphere — the corona — rise to an infernal 3.5 million degrees. Scientists still do not understand the heating process, although the sun’s magnetic field appears to play a key role. The superhot corona powers the supersonic solar winds.

“Until you actually go there and touch the sun, you really can’t answer these questions,” said Nicola J. Fox, the mission scientist. “Why is the corona hotter than the surface of the sun? That defies the laws of nature. It’s like water flowing uphill. It shouldn’t happen.”

The Parker Solar Probe is designed to fill in crucial data, measuring electrical and magnetic fields, cataloging the ingredients of the solar wind and photographing the corona.

Scientists have had a solar probe on their wish list since 1958, but the materials did not exist to protect a spacecraft from the searing heat.

The Parker Solar Probe will be far enough away that it will experience temperatures of thousands, not millions, of degrees, but it still needs a carbon composite heat shield to protect it and its instruments. In 2025, after 24 orbits and 24 swoops through the corona, scientists should have answers to some of their questions.

“I like to call it the coolest hottest mission under the sun,” Dr. Fox said.