28.12.2024
Nasa makes history with closest-ever approach to Sun
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 EST on Thursday (05:00 GMT on Friday) after it had been out of communication for several days during its burning-hot fly-by.
Nasa said the probe was "safe" and operating normally after it passed just 3.8 million miles (6.1 million km) from the solar surface.
The probe plunged into our star's outer atmosphere on Christmas Eve, enduring brutal temperatures and extreme radiation in a quest to better our understanding of how the Sun works.
Nasa then waited nervously for a signal, which had been expected at 05:00 GMT on 28 December.
Moving at up to 430,000 mph (692,000 kph), the spacecraft endured temperatures of up to 1,800F (980C), according to the Nasa website.
"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 endured temperatures of 1,400C and radiation that could have frazzled the on-board electronics.
It was protected by an 11.5cm (4.5in) thick carbon-composite shield, but the spacecraft's tactic was to get in and out fast.
In fact, it moved faster than any human-made object, hurtling at 430,000mph - the equivalent of flying from London to New York in less than 30 seconds.
Parker's speed came from the immense gravitational pull it felt as it fell towards the Sun.
So why go to all this effort to "touch" the Sun?
Scientists hope that as the spacecraft passed through our star's outer atmosphere - its corona - it will have collected data that will 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 faced an anxious wait over Christmas while the spacecraft was out of touch with Earth.
Dr Fox had been expecting the team to text her a green heart to let her know the probe was OK as soon as a signal was beamed back home.
She previously admitted she was nervous about the audacious attempt, but had faith in the probe.
"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."
Quelle: BBC
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Update: 29.12.2024
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Operations teams have confirmed NASA’s mission to “touch” the Sun survived its record-breaking closest approach to the solar surface on Dec. 24, 2024.
Breaking its previous record by flying just 3.8 million miles above the surface of the Sun, NASA’s Parker Solar Probe hurtled through the solar atmosphere at a blazing 430,000 miles per hour — faster than any human-made object has ever moved. A beacon tone received late on Dec. 26 confirmed the spacecraft had made it through the encounter safely and is operating normally.
This pass, the first of more to come at this distance, allows the spacecraft to conduct unrivaled scientific measurements with the potential to change our understanding of the Sun.
Flying this close to the Sun is a historic moment in humanity’s first mission to a star.
NICKY FOX
NASA Associate Administrator, Science Mission Directorate
"Flying this close to the Sun is a historic moment in humanity’s first mission to a star,” said Nicky Fox, who leads the Science Mission Directorate at NASA Headquarters in Washington. “By studying the Sun up close, we can better understand its impacts throughout our solar system, including on the technology we use daily on Earth and in space, as well as learn about the workings of stars across the universe to aid in our search for habitable worlds beyond our home planet.”
Credits: NASA
This video can be freely shared and downloaded at https://svs.gsfc.nasa.gov/14741.
Parker Solar Probe has spent the last six years setting up for this moment. Launched in 2018, the spacecraft used seven flybys of Venus to gravitationally direct it ever closer to the Sun. With its last Venus flyby on Nov. 6, 2024, the spacecraft reached its optimal orbit. This oval-shaped orbit brings the spacecraft an ideal distance from the Sun every three months — close enough to study our Sun’s mysterious processes but not too close to become overwhelmed by the Sun’s heat and damaging radiation. The spacecraft will remain in this orbit for the remainder of its primary mission.
“Parker Solar Probe is braving one of the most extreme environments in space and exceeding all expectations,” said Nour Rawafi, the project scientist for Parker Solar Probe at the Johns Hopkins Applied Physics Laboratory (APL), which designed, built, and operates the spacecraft from its campus in Laurel, Maryland. “This mission is ushering a new golden era of space exploration, bringing us closer than ever to unlocking the Sun’s deepest and most enduring mysteries.”
Close to the Sun, the spacecraft relies on a carbon foam shield to protect it from the extreme heat in the upper solar atmosphere called the corona, which can exceed 1 million degrees Fahrenheit. The shield was designed to reach temperatures of 2,600 degrees Fahrenheit — hot enough to melt steel — while keeping the instruments behind it shaded at a comfortable room temperature. In the hot but low-density corona, the spacecraft’s shield is expected to warm to 1,800 degrees Fahrenheit.
“It’s monumental to be able to get a spacecraft this close to the Sun,” said John Wirzburger, the Parker Solar Probe mission systems engineer at APL. “This is a challenge the space science community has wanted to tackle since 1958 and had spent decades advancing the technology to make it possible.”
By flying through the solar corona, Parker Solar Probe can take measurements that help scientists better understand how the region gets so hot, trace the origin of the solar wind (a constant flow of material escaping the Sun), and discover how energetic particles are accelerated to half the speed of light.
“The data is so important for the science community because it gives us another vantage point,” said Kelly Korreck, a program scientist at NASA Headquarters and heliophysicist who worked on one of the mission’s instruments. “By getting firsthand accounts of what’s happening in the solar atmosphere, Parker Solar Probe has revolutionized our understanding of the Sun.”
Previous passes have already aided scientists’ understanding of the Sun. When the spacecraft first passed into the solar atmosphere in 2021, it found the outer boundary of the corona is wrinkled with spikes and valleys, contrary to what was expected. Parker Solar Probe also pinpointed the origin of important zig-zag-shaped structures in the solar wind, called switchbacks, at the visible surface of the Sun — the photosphere.
Since that initial pass into the Sun, the spacecraft has been spending more time in the corona, where most of the critical physical processes occur.
“We now understand the solar wind and its acceleration away from the Sun,” said Adam Szabo, the Parker Solar Probe mission scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This close approach will give us more data to understand how it’s accelerated closer in.”
Parker Solar Probe has also made discoveries across the inner solar system. Observations showed how giant solar explosions called coronal mass ejections vacuum up dust as they sweep across the solar system, and other observations revealed unexpected findings about solar energetic particles. Flybys of Venus have documented the planet’s natural radio emissions from its atmosphere, as well as the first complete image of its orbital dust ring.
So far, the spacecraft has only transmitted that it’s safe, but soon it will be in a location that will allow it to downlink the data it collected on this latest solar pass.
The data that will come down from the spacecraft will be fresh information about a place that we, as humanity, have never been.
JOE WESTLAKE
Heliophysics Division Director, NASA Headquarters
“The data that will come down from the spacecraft will be fresh information about a place that we, as humanity, have never been,” said Joe Westlake, the director of the Heliophysics Division at NASA Headquarters. “It’s an amazing accomplishment.”
The spacecraft’s next planned close solar passes come on March 22, 2025, and June 19, 2025.