IBEX, the Interstellar Boundary Explorer, studies the boundary between the heliosphere and the interstellar medium by observing energetic neutral atoms created as the solar wind hits interstellar gas. They have just released the first scientific results and associated sky maps from the data collected by IBEX. There's a surprise within the results: IBEX observed a ribbon around the heliosphere that is a dense source of energetic neutral atoms, something that was completely unpredicted by any of the theoretical models. There also seems to be fine structure within the ribbon, something else completely unpredicted and suggesting something weird is going on in the boundary between the heliosphere and the interstellar medium.
Remember how NASA's M3 instrument on ISRO's Chandrayaan-1 spacecraft confirmed the sparse existence of water all over the surface of the Moon? One of the speculations was that the water formed as protons, which are basically hydrogen atoms without electrons, combine with the oxygen in lunar rock. And it seems that this is indeed the case as the ESA's SARA instrument on the same spacecraft had collected data showing that a substantial number of protons in the solar wind are being absorbed by the lunar regolith.
NASA's IBEX, the Interstellar Boundary Explorer, is a mission to explore the boundary between the heliosphere and interstellar space. The heliosphere is the region of space where our Sun reigns, swept out by the solar wind, while interstellar space is full of the interstellar gas and dust that pervades our galaxy. Another cool thing about IBEX is that it's a lightweight spacecraft launched on Pegasus, a small air-launched rocket.
But Pegasus is a dinky little rocket. Considering that the Voyager spacecrafts took almost three decades to reach the termination shock, and that it should take them a couple of more decades to reach the edge of the heliosphere, there's no way Pegasus could propel IBEX to the boundary in a reasonable amount of time. So it got me wondering just how IBEX is supposed to explore the heliosphere without actually getting there.