US Space agency NASA has just sent the Parker Solar Probe on a path to the sun. The small spacecraft is expected to reach the sun’s atmosphere by November. After a one-day delay, the probe took off early last Sunday, August 12th on a Delta IV Heavy rocket from Cape Canaveral.
The probe is named after 91-year-old solar physicist Eugene Parker, who introduced the idea of solar wind in 1958, and is the only living scientist to have a NASA craft named after them . Solar wind is a stream of charged particles that flow from the sun.
After six weeks the probe will reach Venus, where it will swing around the planet to aim for the sun, making the approach to the sun in November. Once there it will make 24 orbits, spending alternating periods in the corona and farther out in space where it can transmit information to Earth. This information will include insight into hot plasmas, charged particles and the electromagnetic environment which will help solve certain long-held questions in solar astronomy. For one, although heat is usually dissipated as it moves away from it's source, the corona of the sun is much hotter than the surface, and the reason remains unclear. It is also unknown by what forced cause the acceleration of the solar winds into space.
In order to withstand the brutal heat in the corona, many advances have been put to use in the probe's design. NASA first had to find materials that can withstand the intense heat. The heat of corona, even at millions of degrees Celsius, poses little danger to spacecraft, due to it's diffuse nature. Parts of the probe must be able to withstand 1370° C temperatures due to direct sunlight exposure. An instrument called SWEAP (Solar Wind Electrons Alphas and Protons) will catch charged particles with a Faraday cup, a special sensor made of alloys of niobium, titanium, zirconium, molybdenum and tungsten. Sapphire, an excellent insulator, lines certain exposed power cables, while the probe's heat shield is composed of specialized carbon materials.
