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.
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.
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.
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.
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.
The released encounter data encompasses measurements made during the first two solar encounters, spanning the time between Oct. 31 and Nov. 12, 2018, and March 30 and April 19, 2019, when the spacecraft was within 0.25 AU of the Sun, as well as data collected at farther distances. One AU, or astronomical unit, is about 93 million miles, the average distance between the Sun and Earth.
Science teams led by principal investigators from partner institutions have been busy poring over the wealth of information collected by Parker Solar Probe in preparation for the mission’s first science results, to be released later this year. The four instrument suites onboard – FIELDS, ISʘIS, SWEAP, and WISPR – have been observing the characteristics of the solar wind (fields, waves, flows, and particles) in the immediate environment surrounding the Sun, called the corona.
“Parker Solar Probe is crossing new frontiers of space exploration, giving us so much new information about the Sun,” said Parker Solar Probe Project Scientist Nour E. Raouafi, from the Johns Hopkins Applied Physics Laboratory, or APL, in Laurel, Maryland, which manages the mission for NASA. “Releasing this data to the public will allow them not only to contribute to the success of the mission along with the scientific community, but also to raise the opportunity for new discoveries to the next level.”
With three of 24 planned solar orbits under its belt, Parker Solar Probe will continue to get closer to the Sun in the coming years, eventually swooping to within 4 million miles of the Sun’s surface, facing heat and radiation like no spacecraft before it. 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. The mission launched in 2018 and is slated to perform its primary science mission until 2025.
At just before 1:50 p.m. EDT on Sept. 1, 2019, NASA’s Parker Solar Probe completed its third close approach of the Sun, called perihelion. At the time of perihelion, the spacecraft was about 15 million miles from the Sun’s surface, traveling at more than 213,200 miles per hour.
Mission controllers at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, received a green “A” beacon from the spacecraft soon after perihelion, meaning all systems were performing as designed and that the spacecraft was in good health.
This third encounter, which was at approximately the same distance from the Sun and speed as the first two, differs in that the spacecraft’s four instrument suites have been on and gathering data for a longer period than other perihelia.
For this third solar encounter, the mission team turned on the instruments when the spacecraft was around 0.45 astronomical units from the Sun on the inbound side of its orbit. (One astronomical unit, or AU, is about 93 million miles, the average distance between the Sun and Earth.) The instruments will be turned off when Parker Solar Probe is about 0.5 AU from the Sun on the outbound side, which will occur on about Sept. 20. For the prior two perihelia, the instruments were on from 0.25 AU prior to and after completing the close approach.
After Parker Solar Probe’s successful first year in space, the mission team has decided to extend science observations as the spacecraft approaches its third solar encounter.
Parker Solar Probe turned on its four instrument suites on Aug. 16, 2019 — earlier than during its previous two solar encounters, extending the observation period from 11 days to about 35 days.
During the spacecraft’s first two solar encounters, the science instruments were turned on when Parker was about 0.25 AU from the Sun and powered off again at the same distance on the outbound side of the orbit. (One AU, or astronomical unit, is about 93 million miles, the average distance between the Sun and Earth.) For this third solar encounter, the mission team turned on the instruments when the spacecraft was around 0.45 AU from the Sun on the inbound side of its orbit and will turn them off when the spacecraft is about 0.5 AU from the Sun on the outbound side.
“We’ve seen very intriguing phenomena below 0.25 AU, and are confident we will see interesting things all the way out to 0.5 AU,” said Nour Raouafi, Parker Solar Probe project scientist at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. “We cannot wait to see how this extended campaign data will compare to our previous data collected during the shorter periods and to the data from previous missions, such as Helios.”
The extended observation time before and after Parker Solar Probe’s perihelion — its closest approach to the Sun during a given orbit — will let scientists capture the evolution of the solar wind over greater distances as it travels away from the Sun. They also hope the additional data will yield more insight into the energetic particles surrounding the Sun, the corona and the overall solar environment.
The data gathered during this period will start downlinking immediately at the end of the extended campaign. The data from the first two encounters will be released to the public in 2019. Parker Solar Probe’s third perihelionwill occur on Sept. 1.
As NASA’s Parker Solar Probe approaches its third encounter with the Sun, mission scientists are hard at work poring over data from the spacecraft’s first two flybys of our star — and thanks to excellent performance by the spacecraft and the mission operations team, they’re about to get something extra.
On May 6, 2019, just over a month after Parker Solar Probe completed its second solar encounter, the final transmission of 22 gigabytes of planned science data — collected during the first two encounters — was downlinked by the mission team at the Johns Hopkins Applied Physics Laboratory, or APL, in Laurel, Maryland.
This 22 GB is 50% more data than the team had estimated would be downlinked by this point in the mission — all because the spacecraft’s telecommunications system is performing better than pre-launch estimates. After characterizing the spacecraft’s operations during the commissioning phase, which began soon after launch, the Parker mission team determined that the telecom system could effectively deliver more downlink opportunities, helping the team maximize the download of science data.
The team has capitalized on the higher downlink rate, instructing Parker Solar Probe to record and send back extra science data gathered during its second solar encounter. This additional 25 GB of science data will be downlinked to Earth between July 24 and Aug. 15.
“All of the expected science data collected through the first and second encounters is now on the ground,” said Nickalaus Pinkine, Parker Solar Probe mission operations manager at APL. “As we learned more about operating in this environment and these orbits, the team did a great job of increasing data downloads of the information gathered by the spacecraft’s amazing instruments.”
There are four instrument suites on Parker, gathering data on particles, waves, and fields related to the Sun’s corona and the solar environment. Scientists use this information — gathered closer to the Sun than any previous measurements — along with data from other satellites and scientific models to expand on what we currently know about the Sun and how it behaves. Data collected during the first two perihelia will be made available to the public later this year.
Parker Solar Probe continues on its record-breaking exploration of the Sun with its third solar encounter beginning Aug. 27, 2019; the spacecraft’s third perihelion will occur on Sept. 1.