Nasa solar probe to make its closest ever pass of sun on Christmas Eve

Nasa’s Parker solar probe is about to make its closest ever fly-by of the sun, passing 3.8 million miles from its surface on Christmas Eve.

The spacecraft will make the record-breaking approach, known as a perihelion, at 6.53am US eastern time (1153 GMT).

The mission team will lose contact with their ship until Friday 27 December, when they are due to receive a “beacon tone”. On 20 December, they received a transmission indicating that everything was operating normally, via Nasa’s Deep Space Network complex in Canberra.

The Parker probe was launched in August 2018 on a seven-year mission to deepen scientific understanding of the sun, as well as helping to forecast space weather events that can impact life on Earth. It is named after Eugene Parker, who pioneered scientific understanding of the sun and died in 2022 at the age of 94.

“No human-made object has ever passed this close to a star, so Parker will truly be returning data from uncharted territory,” Nick Pinkine, the probe’s mission operations manager at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, said in a statement. “We’re excited to hear back from the spacecraft when it swings back around the sun.”

While the 3.8 million mile distance may sound far away, the Parker probe will be in the sun’s outer atmosphere, the corona. If the 93-million mile distance between Earth and the sun’s surface was 100 metres, the spacecraft would be 4 metres away at its closest point.

The ship’s 4.5-inch thick (11.43 cm) carbon-composite shield are designed to protect it from blistering temperatures of about 1,600 to 1,700F (870 to 930C), ensuring that its internal instruments stay close to room temperature.

As it ventures into the unknown, the probe will be flying at a staggering speed of about 430,000mph (690,000km/h), more than 550 times the speed of sound and fast enough to fly from Washington DC to Tokyo in less than a minute.

“As we’re looking for planets in other solar systems that could actually harbour life, we need to understand how our star works so that we can know what kind of stars we’re looking for in other galaxies, as we search for more and more exoplanets,” Dr Nicola Fox, Nasa’s head of science, told the BBC.

Parker is already helping to shed light on some of sun’s biggest mysteries, from the origins of solar wind to the formation of coronal mass ejections – massive clouds of plasma flung through space – and why the corona is hotter than the sun’s surface beneath.

The spaceship has been using flybys of Venus to move it closer into the sun’s orbit, the most recent on 6 November. These have enabled it to send back new data about the planet, such as capturing visible and near-infrared light, giving scientists a new way to see through its thick clouds to the surface. Previously, that had only been done with radar and infrared imagery.

This Christmas Eve journey to the edge of the sun is the first of three record-setting flybys due to be made by the probe. The next two – on 22 March 2025 and 19 June 2025 – are both expected to bring it back to a similarly close distance from the sun.

“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, Parker Solar Probe program scientist at Nasa headquarters in Washington.

Agence France-Presse contributed to this report