In First for a Spacecraft, Parker Solar Probe Autonomously Manages Heat Load on Solar Arrays

Two people in bunny suits stand on either end of a solar array and examine it.
Members of the Parker Solar Probe team examine and align one of the spacecraft’s two solar arrays on May 31, 2018. Credit: NASA/Johns Hopkins APL/Ed Whitman

Two days after Parker Solar Probe flew past Venus toward its rendezvous with the Sun, the spacecraft had drawn close enough to our star that its power-generating solar array wings began to tilt themselves inward – a task directed by the spacecraft itself, based on the rising temperatures – away from the Sun and behind the spacecraft’s heat shield. This is the first time that autonomous, closed-loop solar array angle control based on temperature has taken place on a spacecraft.

This solar array movement, controlled by software within the spacecraft’s main processor, began on Oct. 5, soon after Parker Solar Probe’s distance from the Sun dropped below about 65 million miles.

Read more from the Johns Hopkins University Applied Physics Lab.

Parker Solar Probe Successfully Completes First Venus Flyby

On Oct. 3, Parker Solar Probe successfully completed its flyby of Venus at a distance of about 1,500 miles during the first Venus gravity assist of the mission. These gravity assists will help the spacecraft tighten its orbit closer and closer to the Sun over the course of the mission.

The orbit design for the Parker Solar Probe mission.
The orbit design for the Parker Solar Probe mission. Credit: NASA/Johns Hopkins APL

Detailed data from the flyby will be assessed over the next few days. This data allows the flight operations team to prepare for the remaining six Venus gravity assists which will occur over the course of the seven-year mission.


Fall 2018 Milestones for Parker Solar Probe

We like to call Parker Solar Probe the coolest, hottest, fastest mission under the Sun — and fall 2018 will prove why. Here are a few mission milestones to look forward to over the coming months.

Oct. 3, 2018 (about 4:45 a.m. EDT) — Parker Solar Probe performs its first Venus gravity assist. This maneuver — to be repeated six more times over the lifetime of the mission — will change Parker Solar Probe’s trajectory to take the spacecraft closer to the Sun.

An illustration of Parker Solar Probe passing Venus.
An illustration of Parker Solar Probe passing Venus. Credit: NASA/Johns Hopkins APL/Steve Gribben

Oct. 29, 2018 — Parker Solar Probe is expected to come within 27 million miles of the Sun. This is the record currently held by Helios 2, set in 1976.

Oct. 30, 2018 — Parker Solar Probe is expected to surpass a heliocentric speed of 153,454 miles per hour. This is the record for fastest spacecraft measured relative to the Sun, set by Helios 2 in 1976.

These speed and distance estimates could change after Parker Solar Probe performs its Venus gravity assist on Oct. 3.

Oct. 31 – Nov. 11, 2018 — Parker Solar Probe performs its first solar encounter. Throughout this period, the spacecraft will gather valuable science data. It will not be in contact with Earth because of the Sun’s interference and the orientation needed to keep the spacecraft’s heat shield between it and the Sun. The spacecraft is expected to reach its closest approach on Nov. 5. Like the distance and speed records, this estimate could change after the Venus gravity assist.

December 2018 — Parker Solar Probe will downlink the science data gathered during its first solar encounter.

You can keep up with Parker Solar Probe’s real-time speed and position online, with updates every hour. More mission milestones are also available.

Editor’s note: This post was updated on Oct. 3, 2018, to correct the expected date of first perihelion.