Parker Solar Probe Keeps Its Cool as It Speeds Closer to the Sun

Posted on 04/29/2021 15:14:14

NASA’s Parker Solar Probe has started its eighth science-gathering solar encounter, putting it one-third of the way through its planned journey of 24 progressively closer loops around the Sun.

Its orbit shaped by a gravity-assist flyby of Venus on Feb. 20, at closest approach (called perihelion) on April 29, Parker Solar Probe came within about 6.5 million miles (10.4 million kilometers) of the Sun’s surface, while moving faster than 330,000 miles per hour (532,000 kilometers per hour) – breaking its own records for both speed and solar proximity.

On April 25 the spacecraft -- its four onboard instrument suites now collecting data on the solar environment and the solar wind as it streams from the Sun -- radioed a “tone one” beacon to operators at the Johns Hopkins Applied Physics Laboratory (APL) in Maryland, indicating all systems were normal heading into closest approach. Science data collection will continue through May 4, with the data expected back on Earth by May 28.

“As we get closer to the Sun, we expect to learn even more than we already have about the formation and structure of the solar wind, and the forces that blast it toward and beyond Earth," said Nour Raouafi, Parker Solar Probe project scientist at APL, which also designed and built the spacecraft and manages the mission for the Heliophysics Division of NASA's Science Mission Directorate.

Two and a half years into its seven-year mission, Parker Solar Probe remains healthy while traversing an increasingly hostile space environment. During this orbit alone, the Thermal Protection System shielding the spacecraft is facing temperatures above 1,200 degrees Fahrenheit (650 degrees Celsius). Parker Solar Probe will eventually travel within 4 million miles of the Sun's extremely hot surface, where the TPS must weather temperatures of 2,500 F -- while keeping the systems and instruments in its shadow operating at about 85 F.

"It almost doesn't know it's at the Sun, and that was the goal," said Betsy Congdon, Parker Solar Probe's lead TPS engineer at APL.

"This is all new science, a true mission of discovery, and part of the challenge was designing a spacecraft to study something in an environment that had never been explored and that we didn't completely understand,” added Jim Kinnison, the Parker Solar Probe mission systems engineer at APL. “A lot of engineering and analysis went into making this mission possible, and it's great to see that the spacecraft and its protection systems, with a third of our mission behind us, are performing even better than we expected.”

- Mike Buckley, Johns Hopkins APL

Credit: NASA/Johns Hopkins APL/Steve Gribben