NASA scientists announced on Friday (December 28) that the Parker Solar Probe survived the closest-ever approach to the Sun. The craft was operating normally after it passed just 6.1 million km from the solar surface. This distance might not sound close but Dr Nicola Fox, head of science at NASA, told the BBC, “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 4 cm from the Sun — so that's close.” What is the Parker Solar Probe? Launched in 2018, the Parker Solar Probe was developed as part of NASA’s Living With a Star program to explore aspects of the Sun-Earth system that directly affect life and society on Earth. It is designed to make observations of the Sun’s upper atmosphere, known as the corona, and carries four instrument suites. The probe, which is the size of a small car, “also makes critical contributions to forecasting changes in the space environment that affect life and technology on Earth,” according to a NASA report. Over the years, it has completed 21 orbits around the Sun, with flybys of Venus gradually moving closer to our star. How did it manage to come so close to the Sun? The Parker Solar Probe is the closest any human-made object has ever come to the Sun. Travelling at the speed of 6,92,000km/h, it endured temperatures up to 1,377 degree Celsius when it reached the closest to our star which occurred on December 24. The probe went out of contact during this but the scientists operating it received the signal on the night of December 26. The craft was able to survive such high temperatures as it is protected by a 4.5-inch-thick (11.43 cm) carbon-composite shield. “The spacecraft is outfitted with a cutting-edge heat shield made of a carbon composite foam sandwiched between two carbon plates. The heat shield is so good at its job that, even though the front side will receive the full brunt of the Sun's intense light, reaching 2,500°F (1,371 degree Celsius), the instruments behind it, in its shadow, will remain at a cosy 85°F (29.4 degree Celsius),” a different NASA report said. The probe circulates a single gallon of water through its solar panels which helps it keep its cool — the water absorbs the heat, and then radiates it out into space. What is the significance of this milestone? Scientists are hoping that as the probe passed through the Sun’s outer atmosphere – the corona – it would have collected data that can give clues about some long standing questions. For instance, researchers expect to solve the mystery around why the corona is so hot — temperatures regularly reach 1 million to 2 million degree Celsius there. The data could also give an idea about the origins of solar winds, a continuous flow of material escaping the Sun. A better understanding of solar winds is crucial as it affects not only the space environment but also life on Earth. Solar winds are usually deflected by Earth’s magnetic field, which acts like a protective shield. Still, sometimes particles interact with atoms and molecules in the atmosphere to produce the phenomena of the northern and southern lights. However, a strong solar wind can disrupt power grids, satellites, and communication systems. Speaking about the importance of the Parker Solar Probe’s data, Dr Julia Stawarz of Northumbria University (UK) told The Guardian, “The measurements from Parker solar probe will help us to answer some of the most fundamental questions about how the sun and its extended atmosphere behave that we have had since the very beginning of the space age.” The probe is expected to send back detailed telemetry data on its status on January 1, according to a statement by NASA.
