There were two new pictures posted on the New Horizons Science Operations Center website this morning, of Io, and if you enhance the images a bit, there are two clear volcanic plumes visible on the limb -- Tvashtar and Prometheus are active! I waited a little bit to see if the mission would release their official versions of these pictures, but I couldn't stand waiting anymore -- so here's my version. [EDIT: the official version is now posted here.]
NASA / JHUAPL / SwRI / Animation by E. Lakdawalla
Volcanic plumes on Io
As New Horizons approached the Jupiter system for its flyby, it captured many images of Io to search for active volcanic plumes. This animation is based upon two images captured on February 26, 2007, from a distance of about 4 million kilometers.
These represent one of two sets of Io pics that New Horizons will downlink before closest approach. John Spencer says that the other set will be ones taken at 11:00 on the 28th, from a range of about 2.5 million kilometers. Can't wait to see those! We'll have to wait until mid-March, after the busiest part of the flyby is over, to see more pictures of Io.
It's been a bit quiet here since the Rosetta flyby on Saturday night. Doug is planning to post something more about that but has been waiting for ESA to release more pictures from the other instruments, especially VIRTIS and Alice. I've been waiting on more pictures from New Horizons -- here at last are a couple to show you. The New Horizons science team is now gathered in Maryland, having a busy science meeting, as they wait for news to come from their spacecraft.
The Planetary Society's Bruce Betts is there with the team in Maryland, following the goings-on, and I hope to have some updates from him this week. He emailed this morning to say that the New Horizons mission expects to hear from their spacecraft shortly after noon tomorrow (Eastern time), and that communication will indicate how well the flyby went. In actual fact, there's no reason to doubt that the mechanics of the flyby will go well; the spacecraft doesn't need to take any actions at all to get the necessary gravity assist from Jupiter. It's correctly targeted, and Jupiter is doing all the work now, accelerating the spacecraft; physics dictates that the gravity assist is going to happen. What we don't know is how well the spacecraft will manage to accomplish the enormous list of science activities that it has been ordered to do. These pictures of Io are lovely -- I can't wait to see more from New Horizons!