The Sun has always held a great fascination for humankind due to its incredible life-giving, yet destructive heat, and we might soon know much more about it thanks to NASA’s Solar Probe Plus. This intrepid spacecraft follows in the footsteps of Helios 1 and Helios 2, which launched in 1974 and 1976 respectively and continued returning data about the Sun until the 1980s. This pair of solar probes are still in heliocentric orbit, travelling at record-breaking velocities of 252,792 kilometres (157,078 miles) per hour.
NASA’s Solar Probe Plus is due to set off from Earth on 30 July 2018, getting closer to the Sun than any man-made object ever has before. Back in March, the probe underwent advanced design and testing, meaning that building work was finally given the green light. This exciting development brought the project – which was originally announced back in in 2008 – a step closer to its ultimate goal of getting to within 8.5 solar radii (6 million kilometres/3.7 million miles) of the Sun.
It will do this by swinging around the Sun then using Venus as a flyby anchor, flinging it back towards the Sun at speeds of up to 200 kilometres (125 miles) per second. It will perform the Venus flyby seven times and orbit the Sun 24 times in total. The last three orbits will be the probe’s closest, beating the previous record by seven times.
The mission is being orchestrated by the Johns Hopkins University Applied Physics Laboratory, which was responsible for the MESSENGER craft orbiting Mercury. The lab is using some of the technology from that mission to protect the probe in its most vulnerable stage.
It will be protected from the intense heat of the Sun by using a heat-resistant carbon-composite shield. It must be capable of dealing with temperatures of 1,371 degrees Celsius (2,500 degrees Fahrenheit) heat as well as the radiation that will be blasting out from the star’s surface.
The first of Solar Probe Plus’ two key objectives is to study the outer atmosphere of the Sun, known as the corona, and find out how it is heated. The fact that the corona is so much hotter than the Sun’s visible surface is something that has mystified scientists for years, so an in-situ investigation should help to provide some much needed answers.
The probe will also aim to learn more about solar winds and why they get accelerated. Both of these investigations will help scientists plan missions in the future in order to make the lives of astronauts much safer.
As well as these two crucial tasks, the Solar Probe Plus will be looking into what effect dusty plasma and the Sun’s magnetic fields have on solar winds. These will also help them plan future missions by making it easier to predict what course solar winds are due to take.
All of this is groundbreaking science and technology, from the shields that stop the probe burning up as it gets close to our Sun, to the results that the probe will eventually return. This mission is now just four years away from its scheduled launch and should help to answer many questions about the vital heart of our Solar System.