New Horizons is locked on target for its Jupiter encounter
Alan Stern just posted a detailed update on the status of New Horizons in his PI's Perspective blog on the mission website. Among other things, he wrote that they will not need to fire the spacecraft's thrusters at all to meet their Jupiter aim point for the flyby on February 28. He writes: "We got a formal [navigational] solution telling us we should make a mid-December course correction of about 0.4 meters/second (0.9 miles/hour), but the effort to design and test this engine burn wasn't worth the time it would take away from more important activities, like planning the best possible Jupiter encounter. Moreover, the error induced by skipping this maneuver will be small -- only about 870 kilometers (550 miles) at Jupiter....we'll accept this tiny aim-point error up for now, and then make it up in our planned post Jupiter trajectory flyby clean up engine burn next spring." For perspective, Jupiter is 142,984 kilometers in diameter.
Apart from being an impressive feat of navigation, their cancellation of this trajectory correction maneuver is important for another reason. The mission must have budgeted some amount of fuel for this maneuver. Since they're not using any of that fuel, that means there'll be that much more fuel available for the Kuiper belt phase of the mission. Remember that New Horizons hasn't picked their Kuiper belt targets yet, because, first of all, the targets they're going to pick may not even have been discovered yet, and second of all, they don't yet know how much fuel they'll have available after passing Pluto for aiming New Horizons at those targets. The cancellation of one maneuver may not result in a huge incremental change in their fuel budget, but every drop of fuel widens the cone of possibilities for their route through the Kuiper belt, which has the potential to bring in more choices for targets.
Alan also describes the science highlights from the Pluto sessions at the recent Division of Planetary Sciences meeting in Pasadena, and mentions that Pluto will be going in to solar conjunction from November 19 to 27, limiting communications with New Horizons.