Parker Solar Probe by the Helios 2 spacecraft. The "Parker Solar Probe" concept originates from a predecessor "Solar Orbiter" project conceived in the 1990s. Similar in design and objectives, the "Solar Probe" mission served as one of the centerpieces of the eponymous Outer Planet/Solar Probe (OPSP) program formulated by NASA. The first three missions of the program were planned to be: the "Solar Orbiter", the Pluto and Kuiper belt reconnaissance mission "Pluto Kuiper Express", and the "Europa Orbiter" astrobiology mission focused on Europa. The original "Solar Probe" design used a gravity assist from Jupiter to enter a polar orbit which dropped almost directly
Planet Nine difficult to otherwise explain. "The amount of warp we see is just crazy," she said. "To me, it's the most intriguing evidence for Planet Nine I've run across so far." American astrophysicist Ethan Siegel, who is deeply skeptical of the existence of an undiscovered planet in the Solar System, nevertheless speculates that at least one super-Earth, which have been commonly discovered in other planetary systems but have not been discovered in the Solar System, might have been ejected from the Solar System during a dynamical instability in the early Solar System. Planetary scientist Hal Levison thinks that the chance of