NASA probe will get closer to the sun this Christmas than ever before

The encounter on December 24 around 1 p.m. (CET) was initially unnoticed by anyone, “as we have no radio contact with the probe at that time,” says astrophysicist Volker Bothmer of the University of Göttingen.

The research team does not expect a signal until the night of December 27 – if everything has gone well. “The probe then sends a sign of life to Earth.” This is done via a short, autonomous radio signal – comparable to the flashing of a lighthouse. The first data won’t be available until late January, when the probe’s main antenna points toward Earth. “But it will take a few years to evaluate and understand all the data.” The German helped develop their concept and a wide-angle camera, among other things.

The probe, which is the size of a small car, has a speed of about 690,000 kilometers per hour at its planned point closest to the sun and can withstand temperatures of around 1,000 degrees Celsius, NASA writes. This means that it flies faster than any other object built by humans to date. According to Bothmer, most instruments will burn if the 11.4 centimeter thick carbon heat shield is moved even slightly, including the camera developed with German help.

The researchers expect to discover, among other things, why the outer atmosphere of the Sun is many times hotter than the surface and therefore also how the atmospheres of other stars work. “We don’t know exactly what Christmas presents the sun will give us,” says Bothmer. But he expects surprises. There are numerous questions: How are the solar fluxes generated in the atmosphere? How do solar winds or solar storms form?

First tests in 1970
The probe “Parker Solar Probe” is not the first man-made visitor to the Sun: the German-American probes “Helios 1” and “Helios 2” were launched in the 1970s, but are located at a distance of about 45 million kilometers at a reasonable distance from the retained heat ball.

The ‘Parker Solar Probe’ probe, which was launched in August 2018 and weighs about 700 kilograms, has so far orbited the Sun in highly elliptical orbits and therefore moves alternately close to and far away from the Sun. According to NASA, during its maiden flight in October 2018, it came closer to the sun than any other spacecraft before it, at 42.7 million kilometers.

Researchers hope to obtain important data
In 2021, it became the first probe to fly through the outer layer of the Sun’s atmosphere, called the corona. “For the first time in history, a space probe has touched the sun,” NASA wrote at the time. In 2023, it even came within just over 7 million kilometers of the sun’s surface.

According to Bothmer, the proximity of about six million kilometers means an even deeper immersion in the solar corona. “This will give us data from regions of the solar atmosphere that have never existed before. In this proximity we are in the birthplaces of the solar wind and solar storms.”

For comparison, Earth is on average about 93 million miles from the sun, and the nearest planet, Mercury, is about 36 million miles away. After approaching the sun on December 24, the spacecraft will likely continue in the same elliptical orbit and will approach the star again at a distance of about six million kilometers on March 22 and June 19, Bothmer said. What will happen next is currently being discussed: “We hope we can continue working with the Parker Solar Probe for many years to come.”