Parker Solar Probe heading for third close pass by Sun

An artist’s impression of the Parker Solar Probe approaching the Sun. Image: NASA/Johns Hopkins APL/Steve Gribben

The $1.5 billion Parker Solar Probe is heading for its third close flyby of the Sun on 1 September, and officials say the spacecraft is collecting even more data about the solar wind and the physics of the corona than initially expected.

“We’re very happy,” said Nicky Fox, director of NASA’s Heliophysics Division at NASA Headquarters in Washington, DC. “We’ve managed to bring down at least twice as much data as we originally suspected we’d get from those first two perihelion passes.”

Launched 12 August 2018, the Parker Solar Probe was released on a trajectory that designed to repeatedly carry it past Venus for gravity-assist flybys that will adjust the spacecraft’s orbit to set up at least seven close passes through the Sun’s outer atmosphere, or corona.

A major mystery the spacecraft’s instruments are expected to help solve is what causes the corona to heat up to millions of degrees when the visible surface of the Sun below is much cooler. Passing within 6.1 million kilometres (3.8 million miles) of the Sun’s visible surface, the Parker probe’s heat shield will endure temperatures up to 1,370 degrees Celsius (2,500 Fahrenheit).

Along with studying the physics of the corona, the Parker probe also is monitoring the solar wind in extraordinary detail. A short video based on data collected 6-10 November shows the wind flowing from left to right. A bright streamer is visible stretching from the left edge of the frame with the center of the Milky Way visible at right.

The video appears to speed up and slow down because the Wide-field Imager for Solar PRobe – WISPR – instrument captures more frames during close approach to the sun than it does farther out. The bright “star” in the video that moves into the frame from the left is Mercury.

“The data we’re seeing from Parker Solar Probe’s instruments is showing us details about solar structures and processes that we have never seen before,” said Nour Raouafi, Parker Solar Probe project scientist at the Johns Hopkins Applied Physics Laboratory. “Flying close to the Sun, a very dangerous environment, is the only way to obtain this data, and the spacecraft is performing with flying colours.”

An analysis of data collecting during Parker’s first two orbit will be released later this year.