Nawaat: There has been a great deal of excitement over the past month for the PSP team. Can you tell us about this mission and some of the milestones it is reaching?
Nour Raouafi: Since the advent of the space age almost fifty years ago, NASA has sent missions to explore all corners of the solar system. That includes all the planets, moons, comets, asteroids and even the edge of the solar system; we even have two spacecrafts that are now out of the solar system completely. But there is one place we have not visited yet, and that is the atmosphere of star. This mission, sending a probe to the solar atmosphere, has been around for almost sixty years, yet we hadn’t been able to accomplish it because of technological limitations. Flying into the outer part of the Sun’s atmosphere, what we call the corona, is extremely hard because the probe we send in has to withstand extreme conditions in terms of temperature and radiation. In order for the mission to be successful we have to protect it at all times, and this has not been possible because we hadn’t come up with a material that can dissipate all that heat.
About fifteen years back we found the solution: the Thermal Protection System (TPS) which enabled us to build this spacecraft. This structure has to be facing the Sun at all times to keep the instruments behind it in the shade. Now, we have 24 orbits to get closer and closer to the Sun. When we get very close, about 10 solar radii within a few years from now, the side of TPS facing the Sun will be 1,400˚C. The other side of the craft, which is just 11.5cm thick, will be only 300˚C. One meter behind that, the temperature will be 29˚C. At a certain point, PSP will be flying through structures we see during a total solar eclipse, what we call streamers, in the corona. That’s a testimony to how close it is to the Sun. On November 6, it was flying at 95km/second. When we get closest to the Sun six years from now, the spacecraft will be flying at 200km/second. This means the spacecraft would cross Tunisia from north to south in almost two seconds. That is simply amazing.
So this spacecraft is breaking all types of barriers for us, breaking records in terms of distance to a star, in terms of speed, but also breaking a long-standing tradition of observing a star from far away. Now we are going to visit a star, the ultimate objective in a universe—there is nothing beyond that. We are stepping into a medium we have never visited before, and we certainly will make big discoveries there. And this is the big question that keeps me so excited: what new phenomenon are we going to discover?