Pluto-bound probe faces its toughest task: finding Pluto
J Thoendell stashed this in Space
Only in the last few days before fly-by will the spacecraft be close enough to Pluto to spot it moving side-to-side against the background stars, revealing its distance. And by that point, mission engineers will not be able to make course adjustments.
If New Horizons turns out to be a little closer to or farther away from Pluto than engineers had thought, they will tell the spacecraft to start making scientific observations a little sooner or later than otherwise planned. That way they can be sure to get Pluto in the images and not just swathes of empty space.
The situation is so complex that New Horizons has, unusually, two navigation teams. KinetX Aerospace is the primary one in charge of getting the spacecraft to where it needs to be. But several years ago, NASA added an independent navigation team from JPL.“We’re too late to do any manoeuvres to change the trajectory,” says William Owen, the mission’s lead optical navigation engineer at the Jet Propulsion Laboratory (JPL) in Pasadena, California. “All we can do is figure out when the close approach to Pluto really is compared to when it was supposed to be, and take the time difference and apply that.”
“It’s a little extra incentive to sharpen your pencils and do well,” says Mark Holdridge, the mission encounter manager at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, which manages New Horizons. If the two approaches start to diverge as New Horizons approaches Pluto, NASA will decide whose solution to use.