There are some places in the solar system that humans will never be able to go to. The surface of Venus is surrounded by a thick atmosphere and overwhelming pressure, making it almost impossible to get close to it. External planets like Pluto are currently too far away to be considered except for exploration by robots. And the sun, a bright, burning ball of hydrogen and helium, is too hot and noisy for astronauts to get close to. In our place, an intrepid robotic spacecraft called the Parker Solar Probe has made dramatic swoops toward our star, coming closer than any spacecraft yet to uncover its secrets. Now it is making its final closest approach, grazing inside the Sun’s atmosphere like never before.
“This is a big moment,” said Yangping Guo, a space mission designer at the Johns Hopkins University Applied Physics Laboratory (JHUAPL) in Maryland. “In 60 years of space exploration, the Sun has been the most difficult destination to reach.”
On Christmas Eve, December 24th, Parker will fly just 6.1 million kilometers above the surface of the Sun, or a distance of 9.86 solar radius from the Sun’s center, 10 times closer than Mercury orbits its star. This will be the first of three such close flights. This speed is an astonishing 690,000 km/h, faster than any spacecraft in history (though still only 0.064 percent of the speed of light). During the flyby, Parker travels at such speed that it can travel from London to Paris in less than two seconds. Its speed is so fast that relativistic effects such as time dilation and frame dragging can be recorded by the spacecraft’s instruments.
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The spacecraft will fly through the Sun’s atmosphere, or corona, where it will learn the biggest things about our star, such as why the corona is so much hotter than the Sun’s surface and how the solar wind is accelerated. Some questions remain. Other spacecraft have studied the Sun, but Parker is the only one to get this close. “There’s no precedent,” says Thomas Zurbuchen, former associate administrator for NASA’s Science Mission Directorate. “It’s really an exploration mission.”
Zurbuchen named the spacecraft after the late American solar physicist Eugene Parker, who predicted the existence of the solar wind in the 1950s. The mission, launched in 2018, was the culmination of decades of research into how to “touch” the sun. Getting close to our star is surprisingly difficult. That’s because falling toward the star would require “killing Earth’s orbital velocity,” said Ralph McNutt, chief scientist in JHUAPL’s space division. Scientists have long thought the best way to do that is to fly to Jupiter and then use the gas giant’s gravity to fly toward the sun. Such a mission could get very close to just four solar radii away, but it would be extremely difficult and time-consuming, and would probably only approach the sun once or twice, with an orbital period of nearly five years. That’s all.
In 2007, Guo suggested that Venus’s multiple approaches could instead be used to bring the spacecraft closer to similar distances, even if slightly further away, but with an orbital period of 3. He proposed the added benefit of allowing dozens of transits over several years in less than a month. “The requirement was to get close enough to take samples inside the solar corona,” Guo said. “We now know that we can use seven Venus flybys.” The last flyby occurred on November 6, when the spacecraft swooped down 387 km above the surface of Venus. Since then, it has orbited closer to the Sun than any of its previous 21 orbits in the past six years. The last solar flight, which took place in September, took place about 1 million km, or 10.4 solar radii.
Parker has four instruments to study the sun. This includes a camera to image the star and its surroundings, tools to measure electric and magnetic fields, and two other tools to study the solar particles and plasma that fall on the spacecraft. Through previous missions, Parker helped discover that the magnetic field at the sun’s surface can funnel heat into the corona, and discovered that more particles are coming from the sun than expected. These achievements are largely due to Parker’s first successful penetration and passage of the Sun’s corona in April 2021.
These latest approaches will take the spacecraft deeper into the corona, but it falls short of the supersonic threshold around four solar radii, where the solar wind is thought to reach the speed of sound. Parker’s observations from a relatively remote location, about 10 meters away from the Sun, have also helped scientists understand the difference between “fast” (up to 800 km/s) and “slow” (down to 300 km/s) solar wind. I would like to know what is the cause of this. per second) of various types. “We think the faster winds are coming from the coronal hole, and the slower winds are coming from the edges of the hole,” said Steph Yardley, a solar scientist at Northumbria University in the UK. “But that’s something we’re still debating.” The process also tells us more about how space weather is produced on Earth as the solar wind travels to Earth. “The closer we get to the source region of the particles that create space weather, the more we can learn,” said Joseph, director of the Solar Physics Division of the Science Mission Directorate at NASA Headquarters in Washington, DC. Westlake says.
There are also hopes that Parker will fly past the Sun during an eruption. The Sun is currently in what is called a solar maximum, the peak period of turmoil in our star’s 11-year cycle of activity. This raises the possibility that a coincidentally timed eruption could strike the spacecraft, something that has happened at least once before. “We’d like to see more of these events cluster very close to the Sun, because flares and coronal masses “We need to understand how phenomena like ejection accelerate particles to reach Earth.” It’s relativistic speed. ” Parker also studied the dust-free zone, a hypothetical region near the Sun where debris drifting inward from the solar system’s periphery “evaporates,” said John Wurtzberger, Parker systems engineer at JHUAPL. There is a possibility of encountering it. “We’ve been getting a sense of it as we’ve gotten closer and closer.”
The mission will begin on December 20, when the spacecraft will reach a distance of 0.25 times the distance between the Earth and the sun, approximately 37 million km, or 53 solar radii from the sun. Here, in preparation for entry, the spacecraft first sends a short beacon sound to Earth to confirm that it is in good health. To withstand the narrow passages and the intense conditions that follow, the parka has to hide most of its hardware behind a carbon composite heat shield. This heat shield is so effective that the spacecraft’s equipment behind it remains “basically room temperature,” even though temperatures reach around 1,000 degrees Celsius, Wiltz said. Berger says.
Due to the placement of the spacecraft and its heat shield, and the desire to maximize data return, the spacecraft will not be able to communicate with Earth during this transit. It flies completely autonomously, changing its position slightly to track the movement of the sun and precisely orienting its heat shield in the direction of the star, producing a cone-shaped shadow that completely surrounds your valuable equipment. Masu. Elsewhere on Parker, the only part of the sun visible during the flyby is a small section of solar panels tucked into the side of the spacecraft, generating power from our star’s immense brilliance.
The entire encounter with the Sun will last about a week, with the spacecraft reaching its point of closest approach around 6:40 a.m. ET on Christmas Eve. If you can survive here and avoid instant blindness from the sun’s overwhelming light, which is 500 times stronger than seen from Earth, our star will be 22 It will appear in your field of vision as a gigantic disk twice as large. “It will fill most of the space in front of you,” says Rawafi. Parker’s camera is pointed to the side and will monitor the trajectory of particles as they flow through the surrounding corona while other instruments collect vital data. But what? that’s right They’ll know who’s guessing it is. “We don’t really know,” Zurbuchen said.
The researchers won’t know whether the flyby was successful until Dec. 27, when the spacecraft will reach a radius of 35 degrees to the sun on its way home and send out another beacon signal to signal its survival. The team will then begin preparations to receive the rover’s valuable data starting on New Year’s Day, with data expected to trickle back in the coming weeks and months. In March, Parker will pass close to the Sun again, and in June it will make its final close pass. Due to the gravity of distant Jupiter, the next two flybys will technically bring it slightly closer to the Sun. They are moving closer by about 100 km each, but this is just a rounding error in the millions of kilometers between Parker and our star. In practical terms, the Christmas Eve flyby will bring Parker closer to the sun than he has ever seen.
The conclusion of these close encounters also ends the spacecraft’s primary mission, which may be extended thereafter. For example, Parker could remain in its current orbit to monitor the effects of the waning solar maximum. “It would be surprising to see this decline,” Westlake said. This is because many large-scale solar events are predicted to occur during this period. The spacecraft will begin to move into a more inclined orbit with its remaining fuel, popping out of the ecliptic plane around which most of the planets rotate, allowing it to view the Sun from a slightly different angle and even gaze at the polar regions, but it will take quite a while to fly. It’s expensive but located a little further away. “We want to be very close to the sun,” Rawafi says.
No matter what happens with the mission, the data Parker collects will be studied for years. “This is the closest humans have ever come to reaching the stars,” Westlake said. This record is unlikely to be broken any time soon.
