Parker Solar Probe

Propelled by a recent swing past Venus, NASA’s Parker Solar Probe is healthy and performing normally as it heads toward its next closest approach to the Sun on Nov. 21.

Parker Solar Probe will break its own distance and speed records on that approach – the 10th of 24 planned, progressively closer trips around the Sun – when it comes about 5.3 million miles (8.5 million kilometers) from the Sun’s surface, while reaching top speeds of 101 miles (163 kilometers) per second, or 364,621 miles per hour. The probe’s science instruments are already queued up to measure the properties of the solar wind near its source, but the spacecraft is also making other critical, if not unexpected, discoveries.

“We’re observing higher than expected amounts of dust near the Sun,” said Nour Raouafi, Parker Solar Probe project scientist at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland. “What’s exciting about this is it’s greatly improving our understanding of the innermost regions of our heliosphere, giving us insight into an environment that, until now, was a total mystery.”

Parker Solar Probe designed, built and now operated at APL, does not carry a dust detector. But as dust grains pelt the spacecraft along its path, the high-velocity impacts create clouds of plasma. These clouds produce unique electrical charges that are picked up by several sensors on the probe’s FIELDS instrument, which is designed to measure the electric and magnetic fields near the Sun. Mission scientists have used this data, for example, to construct comprehensive pictures of the structure and behavior of the large cloud of dust that swirls through the innermost solar system.

The visible imaging camera, WISPR, also picks up bits of material expelled from the spacecraft’s structures after impact with those dust grains. But it also images dust structures far away from the spacecraft, such as the dust ring that shares Venus’ orbit. While learning about space dust isn’t a prime mission science goal, the WISPR and FIELDS have planned for specifically investigating near-Sun dust – in a region of the solar system where no mission has ever operated.

The Parker Solar Probe team did prepare for the spacecraft’s precarious trek through this potentially hazardous environment – as early as the initial mission concept phase – at least as well as our scientific community understood it before the probe’s 2018 launch.

“We designed materials and components that survive hypervelocity dust impacts and the effects of the even smaller particles created in these impacts,” said Jim Kinnison, Parker Solar Probe mission systems engineer at APL. “We modeled the makeup and effects of the dust environment, tested how materials react to the dust particles, and installed fault-tolerant onboard systems that are keeping Parker Solar Probe safe in this unexplored region.”

The spacecraft team has noticed that occasionally, the star tracking cameras used as part of the guidance and control system see reflected light from dust and shattering particles that can momentarily disrupt their ability to see stars. Kinnison noted, however, that this doesn’t compromise the safety of spacecraft or instrument operations, and the star trackers aren’t the spacecraft’s only method of controlling where it points. The guidance and control software uses data from the star trackers in tandem with an inertial measurement unit and solar-limb sensors to keep the Thermal Protection System – the heat shield – pointed toward the Sun.

“Because the system was built to be robust and highly autonomous, loss of data from any one source doesn’t affect the ability to control the spacecraft attitude, and in a worst-case situation, can work indefinitely with just the Solar Limb Sensors that watch for unexpected solar illumination on the spacecraft due to attitude errors,” he said. “With PSP now in its 10^th orbit around the Sun, the spacecraft is proving it can handle this unexpected dust environment.”

And that’s good news, he added, with Parker Solar Probe only set to move closer to – and faster around – the Sun. Assisted by two more Venus flybys, in August 2023 and November 2024, Parker Solar Probe will eventually come within 4 million miles (6.2 million kilometers) of the solar surface in December 2024, at speeds topping 430,000 miles per hour.

NASA’s Parker Solar Probe is speeding in toward the Sun after a swing past Venus on Oct. 16, successfully using the planet’s gravity to shape its path for its next closest approach to our star.

At just after 5:30 a.m. EDT, moving about 15 miles (24 kilometers) per second, the spacecraft swooped 2,370 miles (3,814 kilometers) above Venus’ surface. Such gravity assists are essential to the mission to bring Parker Solar Probe progressively closer to the Sun; the spacecraft counts on the planet to reduce its orbital energy, which in turn allows it to travel closer to the Sun and measure the properties of the solar wind near its source.

This was the fifth of seven planned Venus gravity assists. The flyby reduced Parker Solar Probe’s orbital speed by about 6,040 miles per hour (9,720 kilometers per hour), and set it up for its 10th close pass (or perihelion) by the Sun, on Nov. 21.

Parker Solar Probe will break its own distance and speed records on that closest approach, when it comes approximately 5.3 million miles (8.5 million kilometers) from the Sun’s surface — some 1.2 million miles (1.9 million kilometers) closer than the previous perihelion on Aug. 13 – while reaching 101 miles (163 kilometers) per second, or 364,621 miles per hour. Assisted by two more Venus flybys, in August 2023 and November 2024, Parker Solar Probe will eventually come within 4 million miles (6.2 million kilometers) of the solar surface in December 2024.

Parker Solar Probe, which was designed and built at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, is healthy and its systems are operating normally after the Oct. 16 Venus flyby. The flyby operation was monitored by the spacecraft and mission operations teams at APL, through NASA’s Deep Space Network.

By Mike Buckley
Johns Hopkins University Applied Physics Lab

On Sept. 29, NASA’s Parker Solar Probe completed a quick maneuver that positioned the spacecraft for a flyby of Venus next month.

The maneuver, monitored from the mission operations center at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, lasted just five seconds and trimmed the spacecraft’s velocity by 9.7 centimeters per second, or less than a third of a mile per hour. But it was critical for keeping Parker Solar Probe on pace for its next pass by Venus on Oct. 16, when it will use the planet’s gravity to swing toward its tenth close approach to the Sun.

Parker Solar Probe, which was designed and built at APL, is healthy and its systems are operating normally. The spacecraft completed its ninth solar encounter on Aug. 15, at closest approach coming within 6.5 million miles (10.4 million kilometers) of the Sun’s surface. The upcoming Venus gravity assist will send the spacecraft even closer to the Sun’s blazing surface – about 5.6 million miles (9 million kilometers) – on Nov. 21.

Assisted by two additional Venus flybys, Parker Solar Probe will eventually come within 4 million miles (6.4 million kilometers) of the solar surface in late 2024.

Johns Hopkins University Applied Physics Lab

On Aug. 13, 2021, at 5:50 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 ninth close approach to the Sun on Aug. 9.

During this close pass by the Sun — called perihelion — Parker Solar Probe matched 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 Aug. 15.

Johns Hopkins APL: Parker Solar Probe team members reflect on the mission after three years. 

NASA’s Parker Solar Probe is speeding busily through its ninth science-gathering solar encounter, heading toward a close approach of the Sun on Aug. 9 that will take it to within about 6.5 million miles (10.4 million kilometers, or 14.97 solar radii) of the solar surface.

That matches the record-distance of its last closest approach (called perihelion) on April 29; at the same time, the probe will also equal its record-setting flyby speed of 330,000 miles per hour (532,000 kilometers per hour). And, it’s only 2.6 million miles from the ultimate closest approach of 3.8 million miles from the Sun’s surface, which Parker Solar Probe will reach will reach in December 2024.

Designed, built and operated at the Johns Hopkins Applied Physics Laboratory in Maryland, Parker Solar Probe is operating normally heading into perihelion. Using its four onboard instrument suites, the spacecraft will continue collecting data on the solar environment and solar wind for this encounter through Aug. 15, with much of the data from the encounter expected back on Earth by Aug. 18.

“We are getting into the critical phase of the Parker mission and we’re focused on quite a few things during this encounter,” said Nour E. Raouafi, Parker Solar Probe project scientist from APL. “We expect the spacecraft to be flying through the acceleration zone of the perpetual flow of charged particles that make up the solar wind. Solar activity is also picking up, which is promising for studying larger-scale solar wind structures, like coronal mass ejections, and the energetic particles associated with them.

“But you never know what else you’ll find exploring this close to the Sun,” he added, “and that’s always exciting.”

Three years into its seven-year primary mission, Parker Solar Probe remains healthy while traversing a path that will take it directly through the Sun’s outer atmosphere, known as the corona. The Thermal Protection System shielding the spacecraft is already facing temperatures above 1,200 degrees Fahrenheit (650 degrees Celsius). At Parker Solar Probe’s closest approaches, the TPS must withstand temperatures of 2,500 F while keeping the spacecraft and instruments in its shadow operating at about 85 F.

Preparations are underway for the mission’s fifth flyby of Venus, on Oct. 16, which will direct Parker Solar Probe even closer to the Sun for its 10th science orbit, which culminates with its fourth and final perihelion of the year on Nov. 21.

By Mike Buckley
Johns Hopkins University Applied Physics Lab

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.

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

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.

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 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

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 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.

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

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.

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