Parker Solar Probe

Coming off its fifth encounter with the Sun — and the mission’s longest observation campaign yet — Parker Solar Probe is now headed toward Venus.

Early on July 11, 2020 (UTC), the spacecraft will perform its first outbound flyby of Venus, passing approximately 516 miles above the surface as it curves around the planet. Such Venus gravity assists play an integral role in the Parker Solar Probe mission. The spacecraft relies on the planet to rid itself of orbital energy, which in turn allows it to travel ever closer to the Sun after each Venus flyby. The mission’s previous two Venus flybys swooped past the Sun-facing side of the planet, and this will be Parker Solar Probe’s first pass on Venus’ night side.

Parker Solar Probe will witness a brief 11-minute solar eclipse during the maneuver while passing through the shadow of the planet. Utilizing powerful telescopes, the Apache Point Observatory in New Mexico, Lick Observatory in California, and the Keck Observatory in Hawaii will search for Venus aurora from the ground in coordination with Parker Solar Probe’s pass around the planet, weather permitting. Scientists will combine these ground-based observations with data collected by Parker Solar Probe during the flyby to take an unprecedented look at the interactions between Venus and the solar wind.

This Venus flyby sets Parker Solar Probe up for its sixth close pass by the Sun, slated for September 27.  During this perihelion, Parker Solar Probe will travel even closer to the Sun, setting a new record when it passes approximately 8.3 million miles from the solar surface, more than 3 million miles closer than the previous perihelion at 11.6 million miles from the solar surface. The spacecraft’s seventh perihelion is slated for January 17, 2021.

By Justyna Surowiec
Johns Hopkins University Applied Physics Lab

On June 9, 2020, NASA’s Parker Solar Probe signaled the success of its fifth close pass by the Sun, called perihelion, with a radio beacon tone. The spacecraft completed the fifth perihelion of its mission two days prior, flying within 11.6 million miles from the Sun’s surface, reaching a top speed of about 244,225 miles per hour, which matches the spacecraft’s own records for closest human-made object to the Sun and fastest human-made object, set during its fourth orbit on January 29.

Mission controllers at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, received a “status A” beacon from the spacecraft at 4:40 p.m. EDT. Status A is the best of four possible status signals, and indicates that the spacecraft is operating nominally and the instrument suites are collecting science data. This beacon tone comes after a five-day period where communications with the spacecraft were not possible.

After completing the solar encounter on June 13, Parker Solar Probe will travel toward Venus for its third flyby of the planet — the first Venus flyby that will happen as the spacecraft travels away from the Sun, rather than towards the Sun. Parker Solar Probe will use Venus to shed some of its orbital energy and get much closer to the Sun on the following orbit. Passing at an altitude of approximately 516 miles above Venus’ surface — much lower than the previous two flybys but still well above Venus’ atmosphere — Parker Solar Probe will also witness a brief 11-minute solar eclipse during the maneuver while passing through the shadow of the planet.

This fifth orbit around the Sun includes Parker Solar Probe’s longest observation campaign to date. The spacecraft, which has already completed four progressively closer orbits, activated its instruments at a distance of 62.5 million miles from the Sun’s surface on May 9, some 39 million miles farther from the Sun than a typical solar encounter. The full set of instruments will continue to collect data through June 28, markedly longer than the mission’s standard 11-day encounters.

Data from this fifth observation campaign will be downlinked to Earth between late June and mid-August 2020, and will be released to the public in November 2020.

By Justyna Surowiec
Johns Hopkins University Applied Physics Lab

On May 9, 2020, NASA’s Parker Solar Probe began its longest observation campaign to date. The spacecraft, which has already completed four progressively closer orbits around the Sun, activated its instruments at a distance of 62.5 million miles from the Sun’s surface, some 39 million miles farther from the Sun than a typical solar encounter. The four instrument suites will continue to collect data through June 28, markedly longer than the mission’s standard 11-day encounters.

The nearly two-month campaign is spurred by Parker Solar Probe’s earlier observations, which revealed significant rotation of the solar wind and solar wind phenomena occurring much farther from the Sun than previously thought. The earlier activation of the science instruments allows the team to cover a larger range in order to trace the evolution of the solar wind as it moves away from the Sun.

“We have a real opportunity here to see what’s going on in these regions further from the Sun’s corona,” said Nour Raouafi, Parker Solar Probe project scientist at the Johns Hopkins Applied Physics Laboratory. “While our primary goal is to understand the mysteries at the Sun’s corona and the ‘young’ solar wind closer to the Sun, there is evidence indicating very interesting physics to explore earlier in the orbit and link that to what occurs near the Sun. We have the capability to gather this data and see what it yields.”

The spacecraft will reach its closest point to the Sun for this orbit, called perihelion, on June 7. At perihelion, Parker Solar Probe will be about 11.6 million miles from the Sun’s surface, matching its own record for closest human-made object to the Sun set during its fourth orbit on Jan. 29.

After this solar encounter, the spacecraft will swoop by Venus for its first outbound flyby of the planet. This is when Parker Solar Probe will perform its third Venus gravity assist, which will allow the spacecraft to shed some of its orbital energy and get much closer to the Sun on the following orbit. Flying at an altitude of approximately 516 miles above Venus’ surface — much lower than the previous two flybys but still well above Venus’ atmosphere — Parker Solar Probe will also witness a brief 11-minute solar eclipse during the maneuver. All four instrument suites will be on and collecting data about the near-Venus environment and the planet’s night side during the flyby.

Data from this fifth observation campaign will be downlinked to Earth between late June and mid-August 2020, and will be released to the public in November 2020.

By Justyna Surowiec
Johns Hopkins University Applied Physics Lab

NASA’s Parker Solar Probe team released a second collection of science data to the public on April 14, 2020. The release includes science data from all four of Parker Solar Probe’s instrument suites, spanning the mission’s third orbit around the Sun, which began on June 18, 2019 and completed on November 15, 2019. Also included are high-resolution measurements from the FIELDS and SWEAP instruments.

The data files and graphical displays can be accessed through NASA’s Space Physics Data Facility (SPDF) and Solar Data Analysis Center (SDAC), the APL Parker Solar Probe Gateway, and the Science Operation Centers of the four science investigation teams (the University of California, Berkeley; Princeton University; Harvard-Smithsonian Center for Astrophysics; and Naval Research Laboratory.) Data from Parker Solar Probe’s first two orbits is also available.

New findings from the mission’s first record-setting year in space were released in the Dec. 12, 2019 issue of the journal Nature and a special issue of the Astrophysical Journal Supplement Series. Parker Solar Probe’s observations reveal a complicated, active system near the Sun’s surface, including a notable phenomenon called switchbacks, which are traveling disturbances in the solar wind that cause the magnetic field to bend back on itself. These switchbacks may be a major source for the heating and acceleration of the solar wind plasma.

To date, Parker Solar Probe has completed four of its planned 24 orbits around the Sun. It will eventually travel within 4 million miles of the Sun’s surface, facing extreme heat and radiation. The mission seeks to provide new data on solar activity and how the solar corona works, which contributes significantly to our ability to forecast major space weather events that impact life on Earth. Parker Solar Probe launched in 2018 and will conduct its primary science mission until 2025.

By Justyna Surowiec

Johns Hopkins University Applied Physics Lab

Researchers using Parker Solar Probe data released a new wave of research papers in a special supplement of The Astrophysical Journal on Feb. 3, 2020. The supplement, titled Early Results from Parker Solar Probe: Ushering a New Frontier in Space Exploration, includes some 47 papers with new findings based on the mission’s first three solar flybys. Several other papers still under review will be published later as part of this same issue. The introduction for the issue was written by Marcia Neugebauer, who first confirmed the existence of the solar wind after it was predicted by Eugene Parker — namesake of Parker Solar Probe — in 1958.

The new research builds upon initial results released in Nature and discussed at the American Geophysical Union meeting in December 2019.

A few highlights include:

• New analysis of the magnetic switchbacks first discovered by Parker Solar Probe and described in Nature in Dec. 2019 (Dudok de Wit, et al)
• Detailed studies of the slow solar wind, the origins of which are still uncertain, using Parker Solar Probe and other NASA and ESA spacecraft (Rouillard, et al)
• New observations of a coronal mass ejection, observed close to the Sun by Parker Solar Probe and from afar by other NASA missions  (Wood, et al)
• Close measurements of an energetic particle event by Parker Solar Probe and other NASA spacecraft (Leske, et al)

Read coverage of additional research from University of New Hampshire, Queen Mary University of London, the University of Alabama in Huntsville and Southwest Research Institute.

NASA’s Parker Solar Probe is healthy and operating as designed following its fourth close approach to the Sun, called perihelion, on Jan. 29.

Mission controllers at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, received a “status A” beacon from the spacecraft at 5:20 a.m. EST on Feb. 1. Status A is the best of four possible status signals, and indicates that the spacecraft is operating nominally and the instrument suites are collecting science data. This status also indicates that any minor issues that may have occurred were identified and resolved by Parker Solar Probe’s onboard autonomy and fault management systems.

During this perihelion, Parker Solar Probe broke its own records for speed and proximity to the Sun for a human-made object. The spacecraft reached a speed of 244,255 miles per hour (about 393,044 kilometers per hour) as it whipped around the Sun at a distance of 11.6 million miles (about 18.6 million kilometers).

Parker Solar Probe’s heat shield, called the Thermal Protection System, or TPS, reached new record temperatures as well. At this distance from the Sun, computer modeling estimates show that the Sun-facing side of the TPS experienced a blazing 1,134 degrees Fahrenheit (612 degrees C), about 300 degrees hotter than encountered on the spacecraft’s previous three perihelia. The spacecraft and instruments behind this protective heat shield remained at a temperature of about 85 F (30 C). During the spacecraft’s closest three perihelia in 2024-25, the TPS will see temperatures around 2,500 F (1,370 C).

As the mission team learns more about operations and conditions in this region of space, they have increased the amount of time the instruments are on and gathering data. Parker Solar Probe’s fourth solar encounter phase began on Jan. 23, and the spacecraft will continue to acquire science data through Feb. 29, beyond the originally-planned end of the solar encounter phase on Feb. 4. This solar encounter data will be downlinked to Earth beginning in March.

By Geoff Brown

Johns Hopkins University Applied Physics Lab

At 4:37 a.m. EST on Jan. 29, 2020, NASA’s Parker Solar Probe broke speed and distance records as it completed its fourth close approach of the Sun. The spacecraft traveled 11.6 million miles from the Sun’s surface at perihelion, reaching a speed of 244,225 miles per hour. These achievements topple Parker Solar Probe’s own previous records for closest spacecraft to the Sun — previously about 15 million miles from the Sun’s surface — and fastest human-made object, before roughly 213,200 miles per hour.

Parker Solar Probe will continue to fly ever closer to the Sun on its seven-year journey, exploring regions of space never visited before and providing scientists with key measurements to help unveil the mysteries of the solar corona and wind.

As with most of Parker Solar Probe’s close approaches, the spacecraft is out of contact with Earth for several days around perihelion.

By Justyna Surowiec

Johns Hopkins Applied Physics Lab

NASA’s Parker Solar Probe began its fourth solar encounter today at 9:00 a.m. EST, at a distance of about 23.3 million miles from the Sun’s surface. It will reach perihelion, its closest distance to our star, during this orbit on Jan. 29 at about 4:30 a.m. EST.

The fourth perihelion will send the spacecraft within 11.6 million miles of the Sun, closer than its first three perihelia, which were at about 15 million miles from the Sun. The spacecraft’s four instrument suites will acquire data in this new environment, sampling this previously unexplored region around the Sun and potentially revealing new information about the solar wind and atmosphere.

Parker Solar Probe’s first three orbits of the Sun were all approximately the same distance from our star. Following the mission’s second Venus flyby on Dec. 26, 2019, and after one trajectory correction maneuver on Jan. 10, the spacecraft will set new records for distance from the Sun and fastest human-made object during its fourth perihelion; both records are currently held by Parker Solar Probe.

By Geoff Brown

Johns Hopkins Applied Physics Lab

On Dec. 26, Parker Solar Probe successfully completed its second flyby of Venus. The spacecraft used Venus to slow itself down, approaching the planet at a distance of about 1,870 miles from Venus’s surface during the second gravity assist of the mission. This gravity assist maneuver adjusted Parker Solar Probe’s trajectory to set it up for its fourth orbit around the Sun, or perihelion, which will occur on January 29, 2020. The flight operations team will use the data collected during the recent flyby to make adjustments for the remaining five Venus gravity assists which will occur over the course of the seven-year mission.

After nearly 17 months in space culminating with the release of new science data, Parker Solar Probe is right on course for its second Venus gravity assist maneuver. This flyby will set the spacecraft up for its fourth perihelion of the Sun, during which it will set records for spacecraft speed and closest solar distance, while continuing to gather groundbreaking data from within the Sun’s corona to help scientists make new discoveries.

On Dec. 26, at 1:14 p.m. EST, Parker Solar Probe will perform its second Venus flyby, during which the spacecraft will fly within 1,870 miles of Venus, using the planet to slow itself down and adjust its trajectory for an optimal path toward the Sun. This move allows Parker Solar Probe to precisely position itself for a fourth orbit around Earth’s star—with its next close approach, or perihelion, on January 29, 2020—when it will break its own speed and distance records, flying within 11.6 million miles of the Sun’s surface, 20 percent closer than its first three perihelia.

“These gravity assist maneuvers create the enormous orbit reduction required to get Parker Solar Probe close to the Sun,” said Yanping Guo, mission and navigation design manager for Parker Solar Probe at the Johns Hopkins Applied Physics Lab (APL) in Laurel, Maryland. “The seven Venus flybys are connected in a unique sequence, and each of the flybys is chosen not only to make the necessary orbit reductions, but also to hit the subsequent flybys.”

To prepare for this planetary maneuver, the Parker Solar Probe mission operations team at APL performed a small trajectory correction maneuver (TCM) on the spacecraft on Dec. 8. This TCM very accurately lined up the spacecraft for the rendezvous with Venus. After the flyby, the team will perform another TCM to fine-tune Parker Solar Probe’s final approach for its fourth perihelion.

The spacecraft will complete five more of these critical Venus flybys in the coming years in order to gradually pull it closer to the Sun.

By Justyna Surowiec

Johns Hopkins Applied Physics Lab