A NASA space probe that launches on Saturday is embarking on a first-of-its-kind mission. The Parker Solar Probe is taking a red-hot voyage to “touch” the Sun. The probe will hurtle into the Sun’s corona (atmosphere) and come within just 3.8 million miles of our star. The record for getting close to the Sun was set in 1976. NASA’s Helios 2 craft got within 27 million miles—not close enough to reach the outer atmosphere.
The Parker Solar Probe is designed to take solar punishment like nothing before. Its revolutionary heat shield is capable of withstanding 2,500 degrees Fahrenheit. The idea of flying into the Sun’s atmosphere was proposed 60 years ago. NASA itself was a new organization then. But the technology to create a durable heat shield that was light enough to fly has just recently become reality.
NASA’s solar astrophysicists hope to gather information about the structure and function of the Sun. Why is the corona so much hotter that the surface? What drives solar wind—the steady, supersonic stream of charged particles blasting off the corona in all directions? How does the power of the Sun (or any other star in the universe) disrupt spacecraft in orbit—and affect communications and electronics, even from a very great distance?
Parker’s eight-foot heat shield is just four and a half inches thick. It’s an airy carbon foam sandwiched between two carbon sheets. A white ceramic coating reflects sunlight. It’s expected to glow cherry red when bombarded by the extreme solar heat. It will keep the onboard instruments at a comfy “room temperature” without so much as a blister while the craft ducks and dives through the edges of the corona.
The mission is fast-paced. Parker will make its first brush with the Sun in November. But it will orbit many times before making its closest encounters in 2024 and 2025. Eventually it will run out of fuel and be unable to keep its heat shield pointed toward the Sun. At that point, the rest of the craft will burn and break apart.
(NASA Photo, via AP: An artist’s rendering shows the Parker Solar Probe approaching the Sun.)