Author: Abbey Interrante

NASA’s Parker Solar Probe executed a short maneuver on Aug. 26 that kept the spacecraft on course for the mission’s seventh and final planned Venus flyby on Nov. 6.

Operating on preprogrammed commands, Parker fired its small directional thrusters for about 17 seconds, changing its velocity by less than a mile per hour, and setting its trajectory some 386 miles (593 kilometers) closer to a targeted approach point about 240 miles (380 kilometers) above the Venusian surface. The mission operations team at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, where Parker was designed and built, monitored the activity through NASA’s Deep Space Network antenna station in Goldstone, California.

Yanping Guo, Parker Solar Probe mission design and navigation manager at APL, said precise positioning and timing are critical to the Venus flybys, in which Parker uses the planet’s gravity to tighten its orbit around the Sun. The upcoming flyby will be closer to Venus than the previous six gravity assists, and the final piece of a mission design that will swing Parker to within just 3.8 million miles of the Sun’s surface — the closest the spacecraft will come to our star.

“Venus 7 is the critical gravity assist for Parker Solar Probe to eventually achieve its minimum solar distance,” Guo said, adding that the team will likely conduct an additional, smaller maneuver in late October or early November — after the mission’s Sept. 30 solar encounter — to shore up the spacecraft’s path to Venus.

After flying by Venus, Parker will make the first of at least three planned passes at that unprecedented distance — while whizzing past the Sun at a record 430,000 miles per hour — on Dec. 24, 2024.

Parker Solar Probe is currently in its 21^st orbit, about to begin a science encounter that culminates on Sept. 30, 2024, with a close approach (known as perihelion) of about 4.51 million miles (7.26 million kilometers) from the solar surface.

Follow the spacecraft’s journey through the inner solar system on APL’s Parker Solar Probe website.

By Michael Buckley
Johns Hopkins Applied Physics Laboratory

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.

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

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.

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.”

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.

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

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.

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.

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.”

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.    

“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

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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.

As it orbits the Sun, NASA’s Parker Solar Probe encounters some of the most challenging conditions ever faced by a spacecraft: temperatures up to nearly 1,500 degrees Fahrenheit (800 degrees Celsius), space dust that could easily degrade materials and instruments, and intense light and high-speed particles escaping from our closest star.

But four years after launch, the spacecraft is operating exceptionally well and sending back more than twice the planned amount of science data.

“Despite operating in such an extreme environment, Parker is performing well beyond our expectations,” said Helene Winters, Parker Solar Probe project manager at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland. “The spacecraft and its payload are making spectacular observations that will revolutionize our understanding of the Sun and the heliosphere, and that is a testament to the innovation and tireless dedication of the team.”

Building a spacecraft to withstand these conditions for years was a monumental challenge. The mission team at APL had to prepare the spacecraft to operate in an environment that had never been explored before. Parker has weathered it all while flying approximately 2.7 billion miles (4.4 billion kilometers) — roughly the distance from the Sun to Neptune — and doing it faster than any mission before. By comparison, NASA’s New Horizons — the APL-led mission that captured the first images of Pluto — took 8 1/2 years to fly the same distance.

“We designed to worst-case assumptions for things like the thermal environment and the effects of solar radiation on the spacecraft,” said Jim Kinnison, the Parker Solar Probe mission systems engineer at APL. “We’re pleased that all the hard work during the design phase to define those worst-case assumptions has paid off.”

The spacecraft’s stellar performance has opened the door for the team to optimize the amount of science returned from the mission.

“Our telecommunications links are more robust than our worst-case predictions, allowing us to downlink at higher bit rates,” said Kinnison. “As a result, the scientists have been able to collect and downlink about three times more data than planned before launch. This means we’re able to study the Sun in more detail during each encounter but also greatly increase science return when we’re farther away. It also means we can collect data in special circumstances like Venus flybys, well beyond our basic science objectives.”

Over the course of the mission, Parker has sent back roughly 2.8 terabytes of scientific data, approximately equivalent to the amount of data in 200 hours of 4K video. Scientists worldwide will use this data for years to come to develop a better understanding of the Sun’s effects on Earth and our solar system.

“I couldn’t be happier with how the mission is going,” said John Wirzburger, the Parker spacecraft systems engineer at APL. “The spacecraft is operating normally, we’re well within all of our performance margins, and we have plenty of propellant to fly for a long time. Everything is working at least as well, if not better, than expected and modeled on the ground.”

Next month, Parker will complete its 13^th perihelion, its closest approach to the Sun in this orbit. During that encounter, it will fly through the Sun’s upper atmosphere, the corona, for the sixth time.

That environment, though, is getting only more extreme. Parker makes its 13^th approach as the Sun’s activity ramps up prior to solar maximum in 2025 — activity that NASA has reported is already exceeding predictions. This means there are more sunspots, solar flares, and solar eruptions than predicted. However, according to Wirzburger, the Parker team is not concerned about the spacecraft’s continued performance.

“Parker was designed to handle things like radiation and solar flares,” he said. “As some of the bigger solar flares have been released, the spacecraft has weathered the storm each time without issue.”

“Exploration is inherently risky, but the spacecraft has proven to be robust and able to autonomously keep itself safe,” added Kinnison. “We’re looking forward to the rest of the mission, and that closest perihelion at the end of the primary mission.”

By Ashley Hume
Johns Hopkins University Applied Physics Lab

Matching its own records for speed and distance to the Sun, NASA’s Parker Solar Probe completed its 12th close approach to the Sun on June 1, coming within 5.3 million miles (8.5 million kilometers) of the solar surface.

The close approach (known as perihelion) occurred at 6:50 p.m. EDT (10:50 p.m. UTC), with Parker Solar Probe moving about 364,660 miles per hour (586,860 kilometers per hour) – fast enough to cover the distance between Los Angeles and London in under a minute. The milestone also marked the midway point in the mission’s 12th solar encounter, which began May 27 and continues through June 7.

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 University Applied Physics Laboratory in Laurel, Maryland – where it was also designed and built – on June 4.