Enduring molten heat and fierce radiation, the Solar Orbiter aims to show us the Sun as we’ve never seen it before.
The Sun has been subject to detailed scientific scrutiny for decades now. The many filtered images from both terrestrial and orbital telescopes aside, NASA launched the Helios spacecraft in the mid-Seventies to enter an elliptical orbit around the Sun, Helios 2 achieving a world speed record (relative to the Sun) at 252,792 kilometres per hour (149,967 miles per hour).
The Helios spacecraft ceased transmitting data in 1985, however, so the European Space Agency is developing its own solar-orbiting spacecraft, with some international collaboration that includes NASA, who is providing the launcher and some of the scientific instruments the Solar Orbiter will be equipped with.
The spacecraft is scheduled to launch on the back of an Atlas V launch system from NASA’s Kennedy Space Center in Florida in 2017. Once it has reached space, the Solar Orbiter will separate from its launch vehicle and travel to within 45 million kilometres (28 million miles) of the Sun. That’s just beyond the orbit of Mercury and close enough to potentially rival, even beat the world record shortest distance from the Sun (43.4 million kilometres/26.9 million miles) for any man-made vehicle, set by Helios 2 in 1976. Here, under sweltering heat that bakes the daytime side of Mercury to temperatures easily hot enough to melt lead, plus lethal bursts of atomic particles, the Solar Orbiter will swivel its sunshield to permanently face the Sun and deploy a battery of instruments.
Its scientific payload consists of a set of sophisticated instruments weighing in at 180 kilograms (397 pounds), divided into two observational packages. The heliospheric in-situ instruments will scan the Sun’s surface and its atmosphere and includes a high-resolution imager, which will reveal 180-kilometre (111.8-mile) wide solar landscapes in stunning detail that will fascinate both scientists and the public alike. These images alone should enable scientists to glean new insight into the workings of the Sun, while we’ll be able to see gases swirl and react in the powerful magnetic fields on the surface. The remote-sensing instruments will measure the charged particles and magnetic fields immediately around the Solar Orbiter itself, which includes taking measurements of the solar wind in close proximity to its source.
The objectives of the Solar Orbiter across the duration of its seven-year main mission include discovering how solar eruptions produce the energetic particle radiation that fills its heliosphere and where the solar wind originates from within the corona. Of course, that does involve wowing us with insanely detailed images of the Sun, too.