RAS public lecture, 13 October 2015
by Prof Ian Wright, Open University
Writing in advance for a talk about Rosetta is necessarily fraught with uncertainty. For those of us involved with the mission (to rendezvous with, and land on, a comet) we have had to learn to expect the unexpected. So, at the time of writing the orbiter spacecraft has been pulled back to a safe distance from the comet, following a scare with navigation/control during a close fly-by. Since the comet is heading towards the Sun with surface activity increasing all the time, perhaps this means that such excursions will no longer be practical. At the same time, we know that Philae is on the surface, but not where it was intended to be. In fact, it is on its side within a crevice; we don't actually know where it is. Ironically, its orientation means that its chances of survival are greater than they should have been. But, a successful re-start of scientific investigations rests on a balance of spacecraft temperatures and degree of illumination. By the time of the talk the orbiter will hopefully have watched the comet go through and past its closest approach to the Sun ("perihelion"). And, with luck, Philae will have woken up and continued its campaign of analysing the surface. But for now, fingers remain crossed.