The probe will gather more information on solar winds – streams of plasma and particles emitted from the Sun’s surface. These winds which accelerate to speeds of about 250 miles per second as they are jettisoned from the Sun, travel hundreds of millions of miles, spewing past Earth in a constant stream. Earth’s magnetic field deflects the winds. It is a mystery how the winds ultimately break away from the Sun’s gravitational pull.
The probe will be the first to make contact the Sun’s corona, blazing at temperatures up to 2mn degrees Fahrenheit and investigate the acceleration of high-energy particles away from the Sun’s surface. These particles are often associated with events such as solar flares or coronal mass ejections which can damage satellites and even cause power outages on Earth. Scientists hope the probe’s ventures will inform how the volatile corona manages to buoy both solar winds and these high-energy particles into space.
The probe is scheduled to make a final approach to the Sun in late 2024, during which it will come within 3.83mn miles of the Sun’s surface. This is seven times closer than any spacecraft has ever been to the Sun—and closes about 96% of the distance between Earth and its star. In a statement, Nasa said: “The spacecraft and instruments will be protected from the Sun’s heat by a 4.5inch-thick carbon-composite shield, which will need to withstand temperatures outside the spacecraft that reach nearly 2,500F.” The carbon-foam core is 87% hollow. The Sun-facing side is coated in a specialised white paint that dissipates most of the Sun’s heat, guarding the fragile instruments below.
The back of the shield will stay at 600F, and the instruments cloaked within the probe’s bus will remain around 85F. To ensure that the sensitive electronics remains in shadow, the heat shield must always face the Sun. Seven specialised sensors surround the spacecraft, constantly sampling the probe’s exposure to light. If the spacecraft teeters into a precarious position, the sensors will trigger a protective response to rapidly correct the probe’s angle. The probe also comes with a liquid cooling system, packing in five litre of pressurised water that can trickle along little veins along the machinery to maintain a workable ambient temperature.
The spacecraft will also sport instruments like the Solar Probe Cup, designed to scoop up the high energy particles streaming from the Sun’s surface, and a set of telescopes to snap sunlit photos of the sights. At closest approach, the Sun’s power will be 475 times what a satellite orbiting Earth would experience. Scientists have spent six decades working on the project, expected to cost £1bn. The Parker probe is named after American astrophysicist Eugene Parker, 91, who developed a pioneering theory on supersonic solar wind in 1958.