While the Gulf countries and many other parts of the world are experiencing one of the hottest summers ever, Nasa’s Parker Solar Probe (PSP) completed its 20th close approach to the sun on June 30, matching its own distance record by coming about 7.26mn km from the solar surface. The close approach (known as perihelion) occurred with PSP moving 635,266km per hour around the sun, again matching its own record.
On July 2, the spacecraft checked in with mission operators at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, US, (where the spacecraft was also designed and built), with a beacon tone indicating it was in good health and all systems were operating normally. PSP will fly around the sun at the same distance and speed one more time this year — on September 30 — before making the first of its three final planned closest approaches on December 24. At that point, with PSP’s orbit shaped by the mission’s final Venus gravity assist-flyby on November 6, the spacecraft will zoom just 6.1mn km from the solar surface, moving about 692,017km per hour, at its closest approach to the Sun.
On a mission to ‘touch the Sun,’ PSP became the first spacecraft to fly through the corona – the Sun’s upper atmosphere – in 2021. With every orbit bringing it closer, the probe faces brutal heat and radiation to provide humanity with unprecedented observations, visiting the only star we can study up close. To perform its unprecedented investigations, the PSP and its instruments are protected from the Sun by a 4.5-inch-thick carbon-composite shield, which can withstand temperatures reaching nearly 1,377 Celsius.
PSP will revolutionise our understanding of the Sun. The spacecraft is gradually orbiting closer to the Sun’s surface than any before it – well within the orbit of Mercury. Flying into the outermost part of the Sun’s atmosphere, the corona, for the first time, PSP is collecting measurements and images to expand our knowledge of the origin and evolution of solar wind. It also makes critical contributions to forecasting changes in the space environment that affect life and technology on Earth. PSP will fly more than seven times closer to the Sun than any spacecraft. Over seven years, the spacecraft will complete 24 orbits around the Sun.
We live in the Sun’s atmosphere and this mission will help scientists better understand the Sun’s impact on Earth. Data from PSP will be key to understanding and, perhaps, forecasting space weather, which can change the orbits of satellites, shorten their lifetimes, or interfere with onboard electronics. The probe has four instrument suites designed to study magnetic fields, plasma, and energetic particles, and image the solar wind.
PSP was instrumental in observing the unusual and massive outburst from the Sun on April 17, 2021 when high-speed protons and electrons – called solar energetic particles (SEPs) – were hurled at velocities nearing the speed of light and striking several spacecraft across the inner solar system. In fact, it was the first time SEPs were observed by spacecraft at five different, well-separated locations between the Sun and Earth as well as by spacecraft orbiting Mars.
The mission is named for the late Dr Eugene N Parker, who pioneered our modern understanding of the Sun. As a young professor at the University of Chicago in the mid-1950s, Parker developed a mathematical theory that predicted the solar wind, the constant outflow of solar material from the Sun. Throughout his career, Parker revolutionised the field time and again, advancing ideas that addressed the fundamental questions about the workings of our Sun and stars throughout the universe. In 2018, Parker became the first person to witness the launch of a spacecraft bearing his name. He died March 15, 2022, at age 94.