NASA: Record-breaking Parker Solar Probe Now Closer to the Sun Than Any Other Man-made Object

At around 1:04 p.m. EDT on October 29, NASA's Parker Solar Probe passed within 26.55 million miles of the Sun's surface, breaking the record for the closest approach to our star by a man-made object, according to the space agency.

Over the course of its mission, Parker will repeatedly break this record before making a final close approach of 3.83 million miles from the Sun's surface in 2024. The previous close approach record was set in April 1976 by the German-American spacecraft Helios 2.

"It's been just 78 days since Parker Solar Probe launched, and we've now come closer to our star than any other spacecraft in history," Andy Driesman, mission project manager from the Johns Hopkins Applied Physics Laboratory, said in a statement. "It's a proud moment for the team, though we remain focused on our first solar encounter, which begins on October 31."

This encounter will see the probe fly closer and closer to the Sun until it reaches its first "perihelion"— the point in its orbit that is nearest to the sun—at about 10:28 p.m. EDT on November 5.

At this point, the spacecraft will face extreme heat and radiation. However, it will be protected by a cutting-edge protective shield and cooling management system. This technology will enable Parker to make unprecedented observations of our star.

The data collected during flybys such as these over the course of Parker's seven-year mission will have several important implications. For one, it will likely significantly improve our ability to forecast major space-weather events that impact life on Earth.

But researchers also hope that the mission will shed light on three foundational questions about our star that science has not been able to adequately answer yet.

Artist’s concept of the Parker Solar Probe spacecraft approaching the sun. NASA/Johns Hopkins APL/Steve Gribben

One of these puzzles is why the corona—the outermost part of the Sun's atmosphere, which reaches temperatures of several million degrees Fahrenheit—is hundreds of times hotter than the surface. This is counterintuitive, considering that the star's energy is produced in its core.

The second question relates to the acceleration of solar wind—the stream of charged particles that are released from the upper atmosphere.

While scientists understand the origins of the solar wind relatively well, it is unclear exactly where in the Sun's outer layers this acceleration occurs. To shed light on this, Parker will fly directly through the corona, taking direct measurements as it goes.

Finally, the spacecraft could reveal more about the acceleration of "solar energetic particles" (SEPs)—high-energy particles that can approach the speed of light as they are ejected from the Sun. SEPs are of interest to humanity because they can interfere with satellite electronics and pose a danger to life in outer space.