New Horizon spacecraft spots next flyby target, explains study

NASA's New Horizons spacecraft has made the first detection of its next flyby target - an object nicknamed Ultima Thule located in the Kuiper Belt. The probe is scheduled to have a close encounter with Ultima Thule on Jaunary 1, 2019 . 

Scientists had not expected the New Horizons' telescopic Long Range Reconnaissance Imager (LORRI) to be able to see the small, dim object while still over 100 million miles away, against a dense background of stars. Taken on August 16 and transmitted home through NASA's Deep Space Network over the following days, the set of 48 images marked the team's first attempt to find Ultima with the spacecraft's own cameras.

"The image field is extremely rich with background stars, which makes it difficult to detect faint objects," said Hal Weaver, New Horizons project scientist. "It really is like finding a needle in a haystack. In these first images, Ultima appears only as a bump on the side of a background star that's roughly 17 times brighter, but Ultima will be getting brighter and easier to see as the spacecraft gets closer," said Weaver, LORRI principal investigator from the Johns Hopkins Applied Physics Laboratory in the US This first detection is important because the observations New Horizons makes of Ultima over the next four months will help the mission team refine the spacecraft's course toward a closest approach to Ultima.

That Ultima was where mission scientists expected it to be -- in precisely the spot they predicted, using data gathered by the Hubble Space Telescope -- indicates the team already has a good idea of Ultima's orbit. The Ultima flyby will be the first-ever close-up exploration of a small Kuiper Belt object and the farthest exploration of any planetary body in history, shattering the record New Horizons itself set at Pluto in July 2015 by about one billion miles.

These images are also the most distant from the Sun ever taken, breaking the record set by Voyager 1's "Pale Blue Dot" image of Earth taken in 1990. New Horizons set the record for the most distant image from Earth in December 2017.

"Our team worked hard to determine if Ultima was detected by LORRI at such a great distance, and the result is a clear yes," said Alan Stern, New Horizons Principal Investigator from the Southwest Research Institute in the US. "We now have Ultima in our sights from much farther out than once thought possible. We are on Ultima's doorstep, and an amazing exploration awaits!" said Stern.