Todd Barber, Cassini Lead Propulsion Engineer (bio)
Monday greetings from the engineering side of the Cassini flight team! I’m very happy to report via this blog that we just decided to cancel the final Enceladus approach Orbit Trim Maneuver (OTM), OTM-148, and its back-up maneuver labeled JTM-148. Since these burns were scheduled after midnight local time in California last night and tonight, respectively, I don’t think many of us will mourn their cancellation. These final targeting maneuvers for Wednesday’s thrilling close flyby of Saturn’s icy companion were deemed unnecessary, largely due to excellent performance at OTM-147 four days ago. In fact, we were able to save a little bit of propellant for the mission overall by canceling these maneuvers!
We took an engineering image of Enceladus yesterday evening, a so-called “optical navigation” or “op-nav” image. Rather than being used for science, we actually used this image to measure the position of Enceladus very accurately with respect to known background stars. This helped us improve our knowledge of Enceladus’ location, and the result of this latest op-nav is that Cassini remains on target for its historic rendezvous with Enceladus and its icy south polar plumes in two short days. We in engineering wish our science colleagues on the mission a very fruitful and eye-opening close encounter with one of Saturn’s most intriguing moons.