NASA’s Parker Solar Probe Completes 18th Close Approach to the Sun

NASA’s Parker Solar Probe completed its 18th close approach to the Sun on Dec. 28, 2023, matching its own distance record by skimming just about 4.51 million miles (7.26 million kilometers) from the solar surface.

The close approach (known as perihelion) occurred at 7:56 p.m. EST, with Parker Solar Probe traveling at 394,736 miles per hour (635,266 kilometers per hour) around the Sun – also matching the speed record for the 17th solar encounter. The milestone also marked the midway point in the mission’s 18th solar encounter, which began Dec. 24, 2023, and continued through Jan. 2, 2024. 

An illustration of Parker Solar Probe's orbit shows the spacecraft's eighteenth solar encounter on Dec. 28, 2023, at 4.51 million miles from the Sun.
Parker Solar Probe’s 18th orbit included a perihelion that brought the spacecraft within 4.51 million miles of the Sun. Credit: NASA/Johns Hopkins APL/Steve Gribben

The spacecraft entered the encounter in good health, with all systems operating normally. Parker Solar Probe checked back in with mission operators at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland – where the spacecraft was also designed and built – by sending a status beacon tone on Jan. 5.

By Michael Buckley
Johns Hopkins Applied Physics Laboratory

For the Record: Parker Solar Probe Sets Distance, Speed Marks on 17th Swing by the Sun

NASA’s Parker Solar Probe completed its 17th close approach to the Sun on Sept. 27, 2023, breaking its own distance record by skimming just 4.51 million miles (7.26 million kilometers) from the solar surface.

Set up by a gravity-assist flyby of Venus on Aug. 21, the close approach (known as perihelion) occurred at 7:28 p.m. EDT, with Parker Solar Probe moving 394,736 miles per hour (635,266 kilometers per hour) around the Sun – another record. The milestone also marked the midway point in the mission’s 17th solar encounter, which began Sept. 22 and continues through Oct. 3.

An illustration of Parker Solar Probe's orbit shows the beginning of the spacecraft's seventeenth solar encounter on Sept. 22, 2023, at 22.8 million miles from the Sun. The space craft reaches its closest approach to the Sun on Sept. 27, 2023, at 4.5 million miles. The orbit ends on Oct. 3, 2023.
Parker Solar Probe’s 17th orbit included a perihelion that brought the spacecraft within 4.51 million miles of the Sun. Credit: NASA/Johns Hopkins APL/Steve Gribben

The spacecraft entered the encounter in good health, with all systems operating normally. Parker Solar Probe is scheduled to check back in with mission operators at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland – where the spacecraft was also designed and built – by sending a stream of telemetry (status data) on Oct. 1.

The spacecraft will transmit science data from the encounter – largely covering the properties, structure, and behavior of the solar wind as it launches off the Sun – back to Earth from Oct. 4 – 19.

By Michael Buckley
Johns Hopkins Applied Physics Laboratory

Parker Observes Powerful Coronal Mass Ejection ‘Vacuum Up’ Interplanetary Dust

On Sept. 5, 2022, NASA’s Parker Solar Probe soared gracefully through one of the most powerful coronal mass ejections (CMEs) ever recorded – not only an impressive feat of engineering, but a huge boon for the scientific community. Parker’s journey through the CME is helping to prove a 20-year-old theory about the interaction of CMEs with interplanetary dust, with implications for space weather predictions. The results were recently published in The Astrophysical Journal.

A 2003 paper theorized that CMEs may interact with interplanetary dust in orbit around our star and even carry the dust outward. CMEs are immense eruptions from the Sun’s outer atmosphere, or corona, that help drive space weather, which can endanger satellites, disrupt communications and navigation technologies, and even knock out power grids on Earth. Learning more about how these events interact with interplanetary dust could help scientists better predict how quickly CMEs could travel from the Sun to Earth, forecasting when the planet could see their impact.

Parker has now observed this phenomenon for the first time.

“These interactions between CMEs and dust were theorized two decades ago, but had not been observed until Parker Solar Probe viewed a CME act like a vacuum cleaner, clearing the dust out of its path,” said Guillermo Stenborg, an astrophysicist at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, and lead author on the paper. APL built and operates the spacecraft.

This dust is made up of tiny particles from asteroids, comets, and even planets, and is present throughout the solar system. A type of faint glow called zodiacal light, sometimes visible before sunrise or after sunset, is one manifestation of the cloud of interplanetary dust.

The CME displaced the dust all the way out to about 6 million miles from the Sun – about one-sixth of the distance between the Sun and Mercury – but it was replenished almost immediately by the interplanetary dust floating through the solar system.

In-situ observations from Parker were critical to this discovery, because characterizing dust dynamics in the wake of CMEs is challenging from a distance. According to the researchers, Parker’s observations could also provide insight into related phenomena lower down in the corona, such as coronal dimming caused by low-density areas in the corona that often appear after CMEs erupt.

Scientists observed the interaction between the CME and dust as decreased brightness in images from Parker’s Wide-field Imager for Solar Probe (WISPR) camera. This is because interplanetary dust reflects light, amplifying brightness where the dust is present.

In black and white, a cloud from a CME pushes the bright speckles of dust out of the way, leaving a screen of near darkness.
Parker Solar Probe’s Wide Field Imagery for Solar Probe (WISPR) camera observes as the spacecraft passes through a massive coronal mass ejection on Sept. 5, 2022. Coronal mass ejections are immense eruptions of plasma and energy from the Sun’s corona that drive space weather.
Credit: NASA/Johns Hopkins APL/Naval Research Lab

To locate this occurrence of decreased brightness, the team had to compute the average background brightness of WISPR images across several similar orbits – sifting out normal brightness variations that occur due to solar streamers and other changes in the solar corona.

“Parker has orbited the Sun four times at the same distance, allowing us to compare data from one pass to the next very well,” Stenborg said. “By removing brightness variations due to coronal shifts and other phenomena, we were able to isolate the variations caused by dust depletion.”

Because scientists have only observed this effect in connection with the Sept. 5 event, Stenborg and the team theorize that dust depletion may only occur with the most powerful CMEs.

Nevertheless, studying the physics behind this interaction may have implications for space weather prediction. Scientists are just starting to understand that interplanetary dust affects the shape and speed of a CME. But more studies are needed to understand these interactions better.

Parker completed its sixth Venus flyby, using the planet’s gravity to sling itself even closer to the Sun for its next five close approaches. This occurs as the Sun itself is approaching solar maximum, the period in the Sun’s 11-year cycle when sunspots and solar activity are most abundant. As the Sun’s activity increases, scientists hope to have the opportunity to see more of these rare phenomena and explore how they might affect our Earth environment and the interplanetary medium.

Parker Solar Probe was developed as part of NASA’s Living With a Star program to explore aspects of the Sun-Earth system that directly affect life and society. The Living With a Star program is managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland, for NASA’s Science Mission Directorate in Washington. APL designed, built, and operates the spacecraft and manages the mission for NASA.

By Ashley Hume
Johns Hopkins Applied Physics Laboratory

Venus Flyby Sends Parker Solar Probe Toward Record-Setting Flights Around the Sun

NASA’s Parker Solar Probe zoomed past Venus on Aug. 21, using the planet’s gravity to aim toward a record-setting series of flights around the Sun that start next month.

Several people sit in a control room filled with computer screens. One person points at something while talking to a few people sitting at a large desk.
Standing, from left, Parker Solar Probe Mission Operations Manager Nick Pinkine and Project Manager Helene Winters discuss the progress of Parker’s gravity assist flyby of Venus with members of the spacecraft operations team at the Johns Hopkins Applied Physics Laboratory on Aug. 21.
Credit: NASA/ Johns Hopkins APL/Brooke Hammack

At just before 8:03 a.m. EDT, moving approximately 15 miles (more than 24 kilometers) per second, Parker Solar Probe passed 2,487 miles (4,003 kilometers) above the Venusian surface as it curved around the planet toward the inner solar system. The mission operations team at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, kept in contact with the spacecraft during the flyby through NASA’s Deep Space Network – except for an expected 8 minutes at closest approach, when Venus was between Earth and Parker – and determined the spacecraft was on course and operating normally.

“Parker Solar Probe remains on track to make its closest flybys yet of the Sun,” said Nick Pinkine, Parker Solar Probe mission operations manager from APL. “Parker’s success is a tribute to the entire mission team, but I’m especially proud of the mission operators and the job they’ve done over the past five years to ensure the flawless operation of this incredible, history-making spacecraft.”

A woman sits in front of a laptop and a computer screen, looking into the distance, with her hand on her chin.
Guidance and Control Lead Sarah Hefter, of the Johns Hopkins Applied Physics Laboratory, monitors Parker Solar Probe’s trek around Venus in the Parker Mission Operations Center at APL on Aug. 21.
Credit: NASA/Johns Hopkins APL/Brooke Hammack

Venus gravity assists are essential to guiding Parker Solar Probe progressively closer to the Sun; the spacecraft relies on the planet to reduce its orbital energy, which in turn allows it to travel closer to the Sun – where, since 2018, it has been exploring the origins and unlocking the secrets of the solar wind and other properties of the near-Sun environment at their source.

This was the Parker mission’s sixth of seven planned Venus gravity assists. This week’s flyby served as an orbit maneuver applying a velocity change – called “delta-V” – on Parker Solar Probe, reducing its orbital speed by about 5,932 miles per hour (9,547 kilometers per hour). The maneuver changed the spacecraft’s orbit and set Parker Solar Probe up for its next five close passes by the Sun, the first of which occurs on Sept. 27. On each close approach (known as perihelion), Parker Solar Probe will set or match its own speed and distance records when it comes to within just 4.5 million miles (7.3 million kilometers) from the solar surface, while moving close to 394,800 miles per hour.

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

Parker Solar Probe was developed as part of NASA’s Living With a Star program to explore aspects of the Sun-Earth system that directly affect life and society. The Living With a Star program is managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland, for NASA’s Science Mission Directorate in Washington. APL designed, built, and operates the spacecraft and manages the mission for NASA.

By Michael Buckley
Johns Hopkins Applied Physics Laboratory

Durable Parker Solar Probe Going Strong After First Five Years

On Aug. 12, 2018 – five years ago this week – NASA’s Parker Solar Probe blasted off atop a powerful Delta IV rocket from what is now Cape Canaveral Space Force Station. The predawn launch into the skies over the Florida coast marked the start of a game-changing mission to unlock the secrets of the solar wind – and the culmination of decades of development to craft a robotic explorer able to withstand the heat and radiation near the Sun like no other spacecraft before it.

(click to play video)

Designs for a “Solar Probe” started coming together in 1962, just four years after the National Research Council’s Space Studies Board first proposed a mission to explore the environment near the Sun. But the technology to pull off such a bold endeavor, especially the material ingredients for an effective heat shield, just wasn’t available – yet.

8 drawings of iterations of Parker Solar Probe, labeled by year they were designed. The years start at 1982 and end at 2011.
Evolution of a spacecraft: Designs for a Solar Probe changed through the decades, based on technologies and mission plans at the time. NASA’s directive for a Sun-skirting spacecraft led to the design of the Parker Solar Probe mission, which this week celebrates five years in space. Credits: NASA/Johns Hopkins APL

Material advances in the 1970s allowed NASA to begin considering a flyby close enough to directly sample the Sun’s upper atmosphere – the corona – and the solar wind. The initial mission science definition formed in a 1978 workshop at NASA’s Jet Propulsion Laboratory (JPL), but the means to implement the mission would take decades to come together – with JPL and the Johns Hopkins Applied Physics Laboratory (APL) developing concepts for a nuclear-powered Sun skimmer between 1982 and 2005.

In 2007, NASA asked APL to consider a concept for a spacecraft that could cozy up to the Sun, and from that – with the right combination of groundbreaking thermal-protection technologies and clever mission design – evolved the Parker Solar Probe mission that now marks its first half-decade. 

“No matter its form, the core of the mission has always been a close encounter with the Sun,” said Jim Kinnison, Parker Solar Probe mission systems engineer at APL. “It took significant technology development, innovative mission design, and a risk-reducing engineering plan – and now, the Parker team is fulfilling an exploration vision laid out at the dawn of the Space Age.”

People wearing protective white clothing stand around pieces of Parker Solar Probe in a dark room.
Protecting the probe: Engineers from the Johns Hopkins Applied Physics Laboratory prepare the Parker Solar Probe Thermal Protection System – one of the mission’s enabling technologies — for space-environment testing in a thermal vacuum chamber at NASA’s Goddard Space Flight Center, Maryland, in January 2018. Credits: NASA/Johns Hopkins APL/Ed Whitman

After five years of flying through the hottest and dustiest swaths of the inner solar system, Parker Solar Probe – which in 2021 became the first spacecraft to “touch the Sun  – isn’t just surviving, it’s thriving. The spacecraft has returned more than twice the amount of data that scientists expected, making discoveries critical to understanding the source and properties of the solar wind. The spacecraft recently completed its 16th science orbit, out of 24 planned during the primary mission. And on Aug. 21 Parker will zoom past Venus for a gravity assist, a move that will tighten its orbit around the Sun and allow it to take measurements of the Venusian surface and atmosphere.

Thanks to that gravity assist, on Sept. 27, Parker Solar Probe will be traveling at 394,742 miles per hour when it comes within 4.5 million miles of the Sun’s surface – breaking its own speed and distance records around the Sun. It will ultimately dip to within just 3.8 million miles from the Sun, speeding by at 430,000 miles per hour, in December 2024.    

Parker Solar Probe spacecraft in an white room. It's mostly silver and shaped like a cone – smaller on the bottom toward the ground and getting wider toward the top. The top appears white and is flat.
The final design: The actual Parker Solar Probe spacecraft was prepped for launch in a cleanroom at Astrotech Space Operations in Titusville, Florida, in July 2018. Credits: NASA/Johns Hopkins APL/Ed Whitman

“We are in a golden era of heliophysics exploration,” said Nour Raouafi, Parker Solar Probe project scientist at APL. “In just five years, Parker Solar Probe has changed our understanding of the Sun and the activities that connect it to – and affect – life on Earth. As we speed closer and closer to the solar surface, we will learn more about the properties of the Sun itself, but that data will also significantly improve our knowledge of space weather and our ability to live and work in space.”

Learn more at http://www.nasa.gov/parkersolarprobe and http://parkersolarprobe.jhuapl.edu.

Parker Solar Probe was developed as part of NASA’s Living With a Star program to explore aspects of the Sun-Earth system that directly affect life and society. The Living With a Star program is managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland, for NASA’s Science Mission Directorate in Washington. APL designed, built, and operates the spacecraft and manages the mission for NASA.​

By Michael Buckley
Johns Hopkins Applied Physics Laboratory

_______

Background on Solar Probe design history comes from: J. Kinnison, M. K. Lockwood, N. Fox, R. Conde, and A. Driesman, “Solar Probe Plus: A mission to touch the sun,” 2013 IEEE Aerospace Conference, Big Sky, MT, USA, 2013, pp. 1-11, doi: 10.1109/AERO.2013.6496957.

Course Correction Keeps Parker Solar Probe on Track for Venus Flyby

An illustration of Parker Solar Probe flying through solar material.
Artist’s concept of Parker Solar Probe. Credit: NASA’s Goddard Space Flight Center

NASA’s Parker Solar Probe executed a short maneuver on Aug. 3, 2023, that kept the spacecraft on track to hit the aim point for the mission’s sixth Venus flyby on Monday, Aug. 21, 2023. ​

Operating on preprogrammed commands from mission control at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, Parker fired its small thrusters for 4.5 seconds, enough to adjust its trajectory by 77 miles and speed up – by 1.4 seconds – its closest approach to Venus. The precise timing and position are critical to that flyby, the sixth of seven approaches in which Parker uses the planet’s gravity to tighten its orbit around the Sun.

“Parker’s velocity is about 8.7 miles per second, so in terms of changing the spacecraft’s speed and direction, this trajectory correction maneuver may seem insignificant,” said Yanping Guo, mission design and navigation manager at APL. “However, the maneuver is critical to get us the desired gravity assist at Venus, which will significantly change Parker’s speed and distance to the Sun”.

Parker Solar Probe will be moving 394,742 miles per hour when it comes within just 4.5 million miles from the Sun’s surface – breaking its own record for speed and solar distance – on Sept. 27, 2023. Follow the spacecraft’s journey through the inner solar system on the Parker Solar Probe website.

By Michael Buckley
Johns Hopkins Applied Physics Laboratory

NASA’s Parker Solar Probe Completes 16th Close Approach to the Sun

Parker Solar Probe’s 16th orbit included a perihelion that brought the spacecraft within 5.3 million miles of the Sun. Credits: NASA/Johns Hopkins APL/Mike Yakovlev/Josh Diaz

NASA’s Parker Solar Probe accomplished a milestone on June 27, 2023 – its 16th orbit of the Sun. This included a close approach to the Sun (known as perihelion) on June 22, 2023, where the spacecraft came within 5.3 million miles of the solar surface while moving at 364,610 miles per hour. The spacecraft emerged from the solar flyby healthy and operating normally.

On Aug. 21, 2023, Parker Solar Probe will swing past Venus for its sixth flyby of the planet. To prepare for a smooth course, the mission team at the Johns Hopkins Applied Physics Laboratory (APL) applied a small trajectory correction maneuver on June 7, 2023, the first course correction since March 2022. This flyby will be the sixth of seven planned flybys of Venus during Parker’s primary mission. Parker uses Venus’ gravity to tighten its orbit around the Sun and set up a future perihelion at just 4.5 million miles from the Sun’s surface. As the Sun becomes increasingly active, this perihelion will be especially important to learning more about heliophysics.

Parker Solar Probe was developed as part of NASA’s Living With a Star program to explore aspects of the Sun-Earth system that directly affect life and society. The Living With a Star program is managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland, for NASA’s Science Mission Directorate in Washington. APL designed, built, and operates the spacecraft and manages the mission for NASA.

Scientists Shed Light on the Unusual Origin of a Familiar Meteor Shower

Editor’s note: This blog post was updated to include more information about the paper published in The Planetary Science Journal.

Each winter, the Geminid meteors light up the sky as they race past Earth, producing one of the most intense meteor showers in the night sky. Now, NASA’s Parker Solar Probe mission is providing new evidence that a violent, catastrophic event created the Geminids.

Most meteor showers come from comets, which are made of ice and dust. When a comet travels close to the Sun, the ice evaporates and releases gas, dislodging small pieces of the comet and creating a trail of dust. Slowly, this repeated process fills the comet’s orbit with material that produces a meteor shower when Earth passes through the stream.

However, the Geminid stream seems to originate from an asteroid – a chunk of rock and metal – called 3200 Phaethon. Asteroids like Phaethon are not typically affected by the Sun’s heat the way comets are, leaving scientists to wonder what caused the formation of Phaethon’s stream across the night sky.

“What’s really weird is that we know that Phaethon is an asteroid, but as it flies by the Sun, it seems to have some kind of temperature-driven activity. Most asteroids don’t do that,” said Jamey Szalay, a research scholar at Princeton University. Szalay was an author, with Wolf Cukier as the lead author, on the science paper recently published in The Planetary Science Journal.

The research builds on previous work by Szalay and several of his Parker Solar Probe mission colleagues, including the Geminids direct images captured by Karl Battams’ team, to assemble a picture of the structure and behavior of the large cloud of dust that swirls through the innermost solar system. Taking advantage of Parker’s flight path – an orbit that swings it just millions of miles from the Sun, closer than any spacecraft in history – the scientists were able to get the best direct look yet at the dust grains shed from passing comets and asteroids.

Built and operated by the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, Parker Solar Probe does not carry a dedicated dust counter that would give it accurate readings on grain mass, composition, speed, and direction. However, dust grains pelt the spacecraft along its path, and the high-speed impacts create unique electrical signals, or plasma clouds. These impact clouds produce unique electrical signals that are picked up by several sensors on the probe’s FIELDS instrument, which measures electric and magnetic fields near the Sun.

To learn about the origin of the Geminid stream, the scientists used this Parker data to model three possible formation scenarios, and then compared these models to existing models created from Earth-based observations. They found that violent models were most consistent with the Parker data. This means it was likely that a sudden, powerful event – such as a high-speed collision with another body or a gaseous explosion, among other possibilities – that created the Geminid stream.

Parker Solar Probe is part of NASA’s Living with a Star program to explore aspects of the Sun-Earth system that directly affect life and society. The program is managed by NASA’s Goddard Space Flight Center for the Heliophysics Division of NASA’s Science Mission Directorate. APL manages the Parker Solar Probe mission for NASA.

By Desiree Apodaca
Goddard Space Flight Center, Greenbelt, MD

 

Dozens of Observatories Collected Data During Parker Solar Probe’s 15th Close Encounter

Click to play video

NASA’s Parker Solar Probe completed its 15th close approach to the Sun on March 17, coming within 5.3 million miles of the scorching solar surface. The geometry of Parker’s latest orbit also placed it in direct view of Earth and several other Sun-observing spacecraft during its close encounter, providing unique scientific opportunities for collaborative observations from the ground and space.

The European Space Agency’s Solar Orbiter and BepiColombo missions, as well as NASA’s Solar Terrestrial Relations Observatory-A (STEREO-A) spacecraft, observed the Sun from a similar angle as Parker, but at a variety of distances.

“When we can observe the same solar phenomena as they travel from the Sun out into the solar system, we have a notable opportunity to see how structures like the solar wind change as they move through time and space,” said Nour Raouafi, Parker’s project scientist at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. “These additional eyes on the Sun and the inner heliosphere help us see the bigger picture, beyond what Parker can do alone.”

Because Earth was in a prime position to view Parker’s latest encounter, the science community initiated a ground-based observation campaign. More than 40 observatories in the United States, Europe, and Asia trained their visible, infrared, and radio telescopes on the Sun for several weeks around Parker’s encounter.

This was a rare opportunity, as Earth can only view an entire Parker encounter once every three to four orbits. These powerful observatories were not able to see Parker itself — the van-sized spacecraft is far too small for visible detection — but they offered from a distance additional information about the solar sources of phenomena that the probe is observing up close.

“There are several types of observations that we can’t get from Parker, such as images of the Sun, observations of the magnetic field and flares near the solar surface, and coronagraph imaging,” Raouafi said. “This is an important chance to obtain different kinds of information that provide more context for the data Parker sends back and help expand our understanding of our star.”

During the perihelion, the spacecraft traveled at 364,619 miles per hour, fast enough to fly from New York to Tokyo in just over a minute.

As designed, Parker Solar Probe’s autonomy system turned off the high-energy Energetic Particle Instrument (EPI-Hi) on Feb. 13 after the instrument was prematurely power cycled before the completion of a software patch upload. After anomaly recovery planning, the instrument and Parker Mission Operations teams successfully restored the instrument configuration on March 10 in preparation for Solar Encounter 15.

The spacecraft entered the encounter in good health, with all systems operating normally.

Parker Solar Probe was developed as part of NASA’s Living with a Star program to explore aspects of the Sun-Earth system that directly affect life and society. The Living with a Star program is managed by the agency’s Goddard Space Flight Center in Greenbelt, Maryland, for NASA’s Science Mission Directorate in Washington, D.C. APL designed, built, manages, and operates the spacecraft.

By Ashley Hume
Johns Hopkins Applied Physics Laboratory

NASA Notes Parker Solar Probe Instrument Temporarily Offline

An instrument on NASA’s Parker Solar Probe was powered off by the spacecraft autonomy system on Feb. 12. It happened during the application of an approved flight software patch to the Energetic Particle Instrument (EPI-Hi). The instrument team determined the instrument was power cycled prematurely before the patch was completely loaded.

The instrument will remain off for several weeks as the geometry between the spacecraft, Sun, and Earth currently prevents a good uplink. The EPI-Hi is expected to return to normal operations after this blackout period, before the spacecraft begins its 15th close encounter with the Sun on March 12.

The overall spacecraft remains healthy and is functioning as expected and the operation of other Parker instruments has not been impacted.