Parker Solar Probe Ushers in New Science on the Sun and Solar Wind

Scientists using data from NASA’s Parker Solar Probe released a new collection of research papers in a special issue of the journal Astronomy & Astrophysics on June 2, 2021.

The issue, titled Parker Solar Probe: Ushering a New Frontier in Space Exploration, includes 37 papers on discoveries made during mission’s first four orbits around the Sun. The new research builds upon initial results released in Nature in 2019 and a special supplement of The Astrophysical Journal in 2020.

The latest articles include data analysis, theory, and modeling. Among the major topics covered are magnetic switchbacks first discovered by Parker Solar Probe, the role of waves in heating solar plasma, solar angular momentum, the near-Sun dust environment, and the diversity of small energetic-particle events. Highlights include:

      • The enigma of magnetic switchbacks in the “young” solar wind. The switchbacks are more prominent, and play a larger role in the structure of the solar wind, closer to the Sun. Their origin, evolution and contribution to the heating and acceleration of the solar wind plasma is highly debated. Several papers in this issue discuss different aspects of this mysterious feature.
      • Clear evidence of the dust-free zone around the Sun, supporting the initial hints of such a zone published in the 2019 Nature papers.
      • Diverse kinetic and magnetohydrodynamic aspects of plasma — such as wave-particle interactions, magnetic field reconnection, and turbulence — pertinent to the heating and acceleration of the solar wind.
      • New results about large-scale solar wind structures, such as coronal mass ejections and stream interaction regions, and the often-associated solar energetic particles.
A burst of material from the Sun approaches the Parker Solar Probe spacecraft
Among the major topics covered in the Astronomy & Astrophysics papers are magnetic switchbacks first discovered by Parker Solar Probe, the role of waves in heating solar plasma, solar angular momentum, the near-Sun dust environment, and the diversity of small energetic-particle events. Credit: NASA/Johns Hopkins APL/Ben Smith

Designed, built, and operated by the Johns Hopkins Applied Physics Laboratory, or APL, in Laurel, Maryland, Parker Solar Probe recently completed its eighth solar encounter, breaking its own records for speed and proximity to the Sun. It will reach its top speed and closest point to our star — coming within 4 million miles of its surface, moving some 430,000 miles per hour — by December 2024. The Parker Solar Probe project is managed by the Heliophysics Division of NASA’s Science Mission Directorate in Washington, D.C.

“All of the results we’ve reported so far, since Parker Solar Probe began its mission in August 2018, depict conditions of a ‘quiet’ Sun during the solar minimum, or its least active period,” said Nour Raouafi, the Parker Solar Probe project scientist from APL. “Many more discoveries await us as the Sun becomes more active and as the spacecraft reaches deeper into the Sun’s corona.”

By Mike Buckley
Johns Hopkins University Applied Physics Lab

Course Correction Points Parker Solar Probe to Next Venus Flyby

NASA’s Parker Solar Probe executed a small maneuver on May 15, 2021, that corrected the trajectory errors from a gravity-assist flyby of Venus in February — and put the probe on newly optimized path for its next Venus gravity assist on Oct. 16.

The maneuver, monitored from the mission operations center at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, lasted about 39 seconds and tweaked the spacecraft’s velocity by 91 centimeters per second, or about 2 miles per hour. The difference might seem negligible to a spacecraft zooming around the Sun at 330,000 miles per hour, but it was actually enough to fine-tune Parker Solar Probe’s path toward the next three Venus gravity assists.

Diagram of Parker Solar Probe’s latest and next two orbits and close approaches – or perihelion – to the Sun. The diagram includes the dates and locations of planned trajectory correction maneuvers (TCMs) leading up to, and just after, the spacecraft’s fifth Venus gravity assist flyby – VGA5 – on Oct. 16. Having completed the TCM on May 15, 2021, the mission team will evaluate the necessity of the other course-correction maneuvers over the next several months. Credit: NASA/Johns Hopkins APL/Yanping Guo

Parker Solar Probe just completed its eighth close approach to the Sun, coming within a record 6.5 million miles (10.4 million kilometers) of the Sun’s surface on April 29. It’ll pass the Sun from about the same distance again on Aug. 9, before using Venus’ gravity on Oct. 16 to swing it even closer to the surface — about 5.6 million miles (9 million kilometers) — on Nov. 21. Assisted by the remaining three Venus flybys, Parker Solar Probe will eventually come within 4 million miles (6.4 million kilometers) of the solar surface.

The graphic above marks Parker Solar Probe’s location on May 18. The green lines denote the spacecraft’s path since launch on Aug. 12, 2018; the red loops indicate the probe’s future, progressively closer orbits toward the Sun. Credit: NASA/Johns Hopkins APL/Yanping Guo

The team continues to track the spacecraft closely and will evaluate the necessity of other course-correction maneuvers over the next several months. Parker Solar Probe is healthy and its systems are operating normally.

By Mike Buckley
Johns Hopkins University Applied Physics Lab

Successful Eighth Solar Flyby for Parker Solar Probe

On May 2, 2021, at 3:00 a.m. EDT, mission controllers at the Johns Hopkins University Applied Physics Laboratory, in Laurel, Maryland, received a “tone one” beacon from Parker Solar Probe, indicating that all systems were healthy and operating normally after the spacecraft’s eighth close approach to the Sun on April 29.

During this close pass by the Sun — called perihelion — Parker Solar Probe broke its own records for spacecraft distance from the Sun and speed, coming to 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).

Science data collection for this solar encounter continues through May 4.

NASA’s Parker Solar Probe Keeps Its Cool as it Speeds Closer to the Sun

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, 2021, will bring the spacecraft closer to the Sun than on any previous flyby. At closest approach, called perihelion, on April 29, Parker Solar Probe will come 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.

A diagram shows Parker Solar Probe's position close to the Sun, along with outline of its past and future orbits

On April 25, the spacecraft radioed a “tone one” beacon to operators at the Johns Hopkins Applied Physics Laboratory, or APL, in Maryland, indicating all systems were normal heading into closest approach. Parker Solar Probe’s four onboard instrument suites are now collecting data on the solar environment and the solar wind as it streams from the Sun, and science data collection will continue through May 4.

Other ground- and space-based observatories will also capture measurements during this solar encounter in coordination with Parker Solar Probe, including a special observing campaign by NASA’s Solar Dynamics Observatory.

By Mike Buckley
Johns Hopkins University Applied Physics Lab

Parker Solar Probe Primed for Fourth Venus Flyby

NASA’s Parker Solar Probe speeds past Venus on Feb. 20, 2021, using the planet’s gravity to shape its path for its next close approaches to the Sun.

At just after 3:05 p.m. EST, moving about 54,000 miles per hour (about 86,900 kilometers per hour), the spacecraft will pass 1,482 miles (2,385 kilometers) above Venus’ surface as it curves around the planet. Such Venus gravity assists are essential to the mission to bring the spacecraft close to the Sun; Parker Solar Probe relies on the planet to reduce its orbital energy, which in turn allows it to travel closer to the Sun – and inspect the properties of the solar wind closer to its source.

Animation of the Parker Solar Probe spacecraft flying by the planet Venus.
Parker Solar Probe makes its fourth of seven Venus gravity assists on Feb. 20, 2021. Credit: NASA/Johns Hopkins APL/Steve Gribben

This is the fourth of seven planned Venus gravity assists, and will set Parker Solar Probe up for its eighth and ninth close passes by the Sun, slated for April 29 and Aug. 9. During each of those passes, Parker Solar Probe will break its own record when it comes approximately 6.5 million miles (10.4 million kilometers) from the solar surface, about 1.9 million miles closer than the previous closest approach – or perihelion – of 8.4 million miles (13.5 million kilometers) on Jan. 17.

By Mike Buckley
Johns Hopkins University Applied Physics Lab

Parker Solar Probe Marks Seventh Successful Swing around the Sun

There are lots of eyes on the Sun this week, as NASA’s Parker Solar Probe swings around our star on the seventh of its 24 scheduled orbits.

None are closer than Parker Solar Probe, which passed just 8.4 million miles (13.5 million kilometers) from the Sun’s surface while flying at 289,932 miles per hour (466,600 kilometers per hour) on Jan. 17, essentially matching its own records for solar proximity and speed. Around this same time, several spacecraft and dozens of earthbound telescopes were primed to contribute observations that will give scientists a comprehensive and coordinated picture of solar activity.

On Jan. 21, the spacecraft transmitted a “tone one,” indicating all systems were healthy and operating normally after the spacecraft’s close approach to the Sun and heading into the final stretch of the solar encounter, which runs through Jan. 23.

The geometry of this particular orbit means that Parker Solar Probe’s closest approach to the Sun, or perihelion, was in direct view of Earth. Some 40 observatories around the globe, including major installations in Hawaii, the southwestern United States, Europe, and Asia, trained their telescopes on the Sun over the several weeks around the perihelion. About a dozen spacecraft, including NASA’s STEREO, Solar Dynamics Observatory, TIMED, and Magnetospheric Multiscale missions, ESA and NASA’s Solar Orbiter, and ESA’s BepiColombo made simultaneous observations of activity stretching from the Sun to Earth.

Illustration showing the positions of Parker Solar Probe, Earth, and other spacecraft and planets
With Parker Solar Probe’s latest closest approach to the Sun in direct view of Earth, some 40 observatories around the globe and several spacecraft, including STEREO, BepiColombo, and Solar Orbiter, made simultaneous observations of activity stretching from the Sun to Earth. Distances and planet and spacecraft locations are not to scale. Credit: NASA/Johns Hopkins APL/Nate Rudolph

“Parker Solar Probe has shown us that there is a lot more interconnected activity near the Sun than we once thought,” said Parker Solar Probe Project Scientist Nour Raouafi of the Johns Hopkins University Applied Physics Lab, or APL, in Laurel, Maryland. “With this closest approach visible from Earth, we have a fantastic opportunity to put as many eyes as we can on the Sun to help us build a big picture. And we really appreciate the enthusiastic cooperation of so many observatory and mission teams to make that happen.”

Now just over two years into its seven-year mission, the Parker Solar Probe spacecraft will eventually travel within 4 million miles of the Sun’s surface. The mission’s primary goal is to provide new data on solar activity and the workings of the Sun’s outer atmosphere – the corona – which contributes significantly to our ability to forecast major space weather events that impact life on Earth.

The spacecraft will make three more progressively close passes to the Sun in 2021 alone, as well as two gravity-assist flybys at Venus in February and October to adjust the trajectory of its orbit. After zipping past Venus on Feb. 20, Parker Solar Probe will again make close approaches to the Sun on April 29 and Aug. 9. Following another Venus gravity assist on Oct. 16, the spacecraft will make an even closer solar pass on Nov. 21, with perihelion just 5.3 million miles from the Sun’s surface.

“This is our busiest year since launch, and it only gets busier as our trajectory takes us closer and closer to the Sun,” said Parker Solar Probe Project Manager Helene Winters of APL. “This is exactly what the spacecraft was designed for – it’s operating just as we expected and is giving us even more data than anticipated. We’re ready for a range of discoveries in this unexplored region of the Sun.”

Related Video: Watch how data travels from Parker Solar Probe to Earth

By Mike Buckley
Johns Hopkins University Applied Physics Lab

Parker Solar Probe Gears Up for Seventh Solar Pass

NASA’s Parker Solar Probe will make its next close approach to the Sun on Jan. 17, 2021, during its seventh science-gathering orbit around our star. At its closest approach to the Sun, called perihelion, the spacecraft will reach about 8.4 million miles (13.5 million kilometers) from the Sun’s surface, while traveling at a speed of around 289,930 miles per hour.

Diagram showing Parker Solar Probe's position in space on Jan. 15 as it approaches the seventh perihelion pass of its mission

Data from Parker Solar Probe’s Fifth Orbit Now Available

Data from Parker Solar Probe’s fifth orbit around the Sun is now available to the public.

This latest batch of science data was collected by Parker Solar Probe’s four instrument suites this past summer, and covers the mission’s fifth solar encounter — including closest approach to the Sun, called perihelion, on June 7— and a special observation period for the mission’s third Venus flyby in July.

The data 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, BerkeleyPrinceton UniversityHarvard-Smithsonian Center for Astrophysics; and the Naval Research Laboratory).

Illustration of Parker Solar Probe making its fifth perihelion pass of the Sun
Parker Solar Probe made its closest approach to the Sun for its fifth orbit on June 7, 2020. Credit: NASA/Johns Hopkins APL/Steve Gribben

In September, Parker Solar Probe completed its sixth solar encounter. Data from this sixth encounter will be released in February 2021, and early review by the science team has already revealed the mission’s first observation of a sungrazing comet.

Next year will be record-setting for Parker Solar Probe. Starting in January, the spacecraft, built and operated by the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, will embark on four solar encounters and two Venus flybys throughout 2021. The spacecraft will travel even closer toward the Sun’s blazing atmosphere, capturing unprecedented data on solar activity and breaking its own speed and distance records multiple times in the process. 

Parker Solar Probe’s next solar encounter — on Jan. 12-23, 2021 — will carry the spacecraft around the Earth-facing side of the Sun, providing an opportunity for joint observations with multiple ground-based observatories and several space missions. The coordinated observation campaign organized by the mission’s science team will include NASA’s Solar Dynamics Observatory and STEREO spacecraft, ESA’s BepiColombo, and ESA and NASA’s Solar Orbiter and SOHO missions.

By Justyna Surowiec
Johns Hopkins University Applied Physics Lab

Parker Solar Probe ‘Phones Home’ After Sixth Sun Flyby

Zooming away from the Sun, NASA’s Parker Solar Probe checked in with its operators on Earth early on Sept. 30, 2020, letting them know it’s healthy and operating normally after another record-setting close approach to our star on Sept. 27.

Flight controllers at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, received a “Status A” signal from the spacecraft through NASA’s Deep Space Network at 4:45 a.m. EDT; Status A is the best of four possible status signals, and indicates that the spacecraft is operating nominally.

Illustration showing Parker Solar Probe completing a solar flyby with text: "Perihelion 6 - September 27, 2020, 8.4 million miles from the Sun"
Credit: NASA/Johns Hopkins APL/Steve Gribben

The beacon comes after a six-day stretch when communications with the spacecraft were not possible as it wheeled around the Sun. This is the first sign of a successful solar encounter; this sixth solar encounter began Sept. 21 and continues through Oct. 2.

At closest approach (called perihelion) on Sept. 27, Parker Solar Probe came within about 8.4 million miles (13.5 million kilometers) of the Sun’s surface — less than one-tenth of the distance between Earth and the Sun — while reaching a top speed of 289,927 miles per hour (466,592 kilometers per hour), breaking its own records for speed and solar distance.

The team will begin downlinking data from this solar encounter on Oct. 3, giving it more information about the spacecraft’s condition and performance of the science instruments during the flyby.

By Mike Buckley

Johns Hopkins University Applied Physics Lab

Parker Solar Probe Speeds toward Record-Setting Close Approach to the Sun

Propelled by a midsummer flyby of Venus, NASA’s Parker Solar Probe has started yet another record-setting, science-gathering swing around the Sun, its sixth flyby of our star.

Some instruments on the spacecraft have been turned on since late August, collecting data on the near-Sun environment and the solar wind as it streams from our star. At closest approach (called perihelion) on Sept. 27, Parker Solar Probe will come within about 8.4 million miles (13.5 million kilometers) of the Sun’s surface while moving 289,927 miles per hour (466,592 kilometers per hour) — shattering its own records on both counts.

This also marks the first time Parker Solar Probe will dip to within 0.1 astronomical units of the Sun’s center; an “AU” is 93 million miles, the average distance between Earth and the Sun.

“After our last orbit — during which we started science operations much farther out than this encounter — we’re returning our focus to the solar wind closer to the Sun,” said Nour Raouafi, Parker Solar Probe project scientist at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. “We always wonder if we’ll see something new as we get closer and closer. And as the solar cycle rises and the Sun becomes more active, we’ll be able to observe that activity from an unprecedented vantage point.”

Two years into its journey, Parker Solar Probe remains healthy and operating normally. As it continues its seven-year mission, the spacecraft will eventually travel within 4 million miles of the Sun’s extremely hot surface. The mission’s primary goal is to provide new data on solar activity and the workings of the Sun’s outer atmosphere — the corona — which contributes significantly to our ability to forecast major space weather events that impact life on Earth.

This weekend’s perihelion was set up by the probe’s third Venus flyby. On July 11, the spacecraft came within 518 miles above Venus’ surface — much lower than the previous two flybys but still well above Venus’ atmosphere — putting it on a path that brings it 3.25 million miles closer to the Sun than the last perihelion, on June 7. Mission Design and Navigation Manager Yanping Guo of APL noted that the gravity assist provided the mission’s largest orbital speed reduction since launch, trimming the spacecraft’s velocity by 8,438 miles per hour (13,579 kilometers per hour).

Related: Watch how data travels from Parker Solar Probe to Earth.

By Mike Buckley

Johns Hopkins University Applied Physics Lab