A NASA spacecraft has made history by surviving the closest-ever approach to the Sun.
Scientists received a signal from the Parker Solar Probe just before midnight on Thursday, after several days of silence during its intense fly-by.
NASA confirmed that the probe was “safe” and functioning normally after passing just 3.8 million miles (6.1 million km) from the Sun’s surface.
On Christmas Eve, the probe entered the Sun’s outer atmosphere, withstanding extreme temperatures and radiation as part of its mission to deepen our understanding of the Sun’s behavior.
NASA had anxiously awaited a signal, which was expected at 05:00 GMT on December 28. Traveling at speeds of up to 430,000 mph (692,000 kph), the spacecraft experienced temperatures as high as 1,800°F (980°C), according to NASA.
“This close-up study of the Sun allows Parker Solar Probe to take measurements that help scientists better understand how material in this region gets heated to millions of degrees, trace the origin of the solar wind (a continuous flow of material escaping the Sun), and discover how energetic particles are accelerated to near light speed,” the agency said.
Dr Nicola Fox, head of science at Nasa, previously told BBC News: “For centuries, people have studied the Sun, but you don’t experience the atmosphere of a place until you actually go [and] visit it.
“And so we can’t really experience the atmosphere of our star unless we fly through it.”
Parker Solar Probe launched in 2018, heading to the centre of our solar system.
It had already swept past the Sun 21 times, getting ever nearer, but the Christmas Eve visit was record-breaking.
At its closest approach, the probe was 3.8 million miles (6.1 million km) from our star’s surface.
That might not sound that close, but Dr Fox put it into perspective. “We are 93 million miles away from the Sun, so if I put the Sun and the Earth one metre apart, Parker Solar Probe is 4cm from the Sun – so that’s close.”
The probe withstood temperatures of 1,400°C and intense radiation that could have damaged its onboard electronics.
Protected by an 11.5 cm (4.5 in) thick carbon-composite shield, the spacecraft’s strategy was to enter and exit swiftly.
In fact, it became the fastest human-made object, traveling at speeds of 430,000 mph—equivalent to flying from London to New York in under 30 seconds.
Parker’s incredible speed was a result of the immense gravitational pull it experienced as it moved toward the Sun.
So, why all this effort to “touch” the Sun?
Scientists aim to gather data from the spacecraft’s passage through the Sun’s outer atmosphere, or corona, hoping to solve a long-standing mystery.
“The corona is really, really hot, and we have no idea why,” explained Dr Jenifer Millard, an astronomer at Fifth Star Labs in Wales.
“The surface of the Sun is about 6,000C or so, but the corona, this tenuous outer atmosphere that you can see during solar eclipses, reaches millions of degrees – and that is further away from the Sun. So how is that atmosphere getting hotter?”
The mission should also help scientists better understand solar wind – the constant stream of charged particles bursting out from the corona.
When these particles interact with the Earth’s magnetic field the sky lights up with dazzling auroras.
But this so-called space weather can cause problems too, knocking out power grids, electronics and communication systems.
“Understanding the Sun, its activity, space weather, the solar wind, is so important to our everyday lives on Earth,” said Dr Millard.
NASA scientists endured a tense wait over Christmas while the spacecraft was out of contact with Earth.
Dr. Fox had been hoping for a green heart emoji from the team to signal that the probe was safe once the signal was received back on Earth.
Though she had expressed nervousness about the bold mission, she maintained confidence in the spacecraft’s capabilities.
“I will worry about the spacecraft. But we really have designed it to withstand all of these brutal, brutal conditions. It’s a tough, tough little spacecraft.”