Parker Solar Probe makes closest approach to Sun on Christmas Eve as fastest man-made object ever

NASA’s Parker Solar Probe flew just 6.1 million km from the Sun’s surface on December 24. The spacecraft was moving at a speed of 700 000 km/h breaking its previous records for proximity and velocity during its 22^nd perihelion.

“This is one example of NASA’s bold missions, doing something that no one else has ever done before to answer longstanding questions about our universe,” said Arik Posner, program scientist at NASA Headquarters.

The probe’s closest approach occurred during the solar maximum (a peak in the Sun’s 11-year activity cycle) by providing an extraordinary opportunity to observe intense solar phenomena such as coronal mass ejections and magnetic field reversals.

Technical changes

Flying at such proximity required advanced engineering. The probe’s 11.5 cm (4.5 inches) thick carbon-composite heat shield endured extreme temperatures of over 1 400 °C (2 550 °F).

“This is a major engineering accomplishment,” said Adam Szabo, mission scientist at NASA’s Goddard Space Flight Center.

“No human-made object has ever passed this close to a star.”

Mission operators at the Johns Hopkins Applied Physics Laboratory (APL) received a beacon transmission on December 20 confirming all systems were functioning normally and another transmission is expected on December 27 to report the spacecraft’s health after the perihelion.

Timeline and gravity assists

The Parker Solar Probe was launched on August 12, 2018, aboard a Delta IV Heavy rocket and used seven gravity assists from Venus to refine its trajectory. It used 7 gravity assists from Venus to adjust its path and get closer to the Sun with each orbit.

The probe’s 7^th and final Venus flyby on November 6, 2024, adjusted its trajectory for this encounter. It passed within 376 km (233 miles) of Venus by capturing valuable infrared images of the planet’s surface and raised questions about its chemical and geological composition.

Discoveries

The Parker Solar Probe has made a lot of discoveries in solar physics since its launch. It revealed magnetic “switchbacks” that speed up solar wind and observed a dust-free zone near the Sun which is a phenomenon predicted in 1929. The probe also directly sampled the Sun’s corona which is the upper atmosphere made of hot plasma.

The data gathered during the 22^nd perihelion could shed light on the Sun’s magnetic fields, the acceleration mechanisms of the solar wind, and why the corona is hotter than the photosphere despite being farther from the Sun’s core.

“If the Sun gives us one of these humongous explosions, like a coronal mass ejection, when Parker Solar Probe is very close to the Sun, that would be fantastic,” said Nour Raouafi, Parker project scientist at APL.

Future perihelions and the end

The spacecraft is expected to complete 4 more perihelions in 2025 which are scheduled for March 22, June 19, September 15, and December 12. The current encounter remains the main achievement while it may venture slightly closer to the Sun.

The probe will run out of fuel at one point and its parts will be destroyed by the Sun’s intense heat.

“One day, we will run out of fuel for the rocket thrusters that help us control trajectory, and the solar probe will no longer be able to compensate for the pressure of the sunlight. The Sun will flip us around, and the entire backside of the spacecraft should be incinerated in seconds,” Justin Kasper, principal investigator for the mission, explained.

The probe is named after Dr. Eugene Parker, the physicist who first theorized the solar wind, and continues to revolutionize our understanding of the Sun.

“This will be a monumental achievement for all humanity. This is equivalent to the Moon landing of 1969,” Raouafi noted.

References:

¹ Parker Solar Probe Begins Record-Setting Closest Approach to the Sun – NASA – December 20, 2024

² Parker Solar Probe – NASA – Accessed on December 24, 2024

Rishika Yadav

Rishika holds a Master’s in International Studies from Stella Maris College, Chennai, India, where she earned a gold medal, and an MCA from the University of Mysore, Karnataka, India. Previously, she served as a Research Assistant at the National Institute of Advanced Studies, Indian Institute of Science, Bengaluru, India. During her tenure, she contributed as a Junior Writer for Europe Monitor on the Global Politics website and as an Assistant Editor for The World This Week. Her work has also been published in The Hindu newspaper, showing her expertise in global affairs. Rishika is also a recipient of the Women Empowerment Award at the district level in Haryana, India, in 2022.

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