Last week, NASA said it had given "go" to its New Horizon spacecraft, the same craft that made humanity's first visit to Pluto in 2015. The craft is still advancing in our solar system. It is now approaching its next goal, a Kuiper Belt object, billions of miles beyond Pluto, named Ultima Thule. NASA said that after three weeks of searching, no clear barriers in spacecraft's optimum path found no rings, no small moons, no potential hazards. Thus, New Horizons is now focused on the optimal path for its January 1, 2019, meets Ultima Thule.
It will be another first for New Horizons, the longest planet's flying village in human history.
And now we know the spacecraft's path, it takes about 2,200 miles (3,500 km) from Ultima Thule, instead of a risk-filled detour that would have printed it three times further out. The last opportunity to maneuver the spacecraft on another course was December 18th.
While New Horizons is approaching Ultima Thule (officially designated in 2014 MU69), the mission's science team is puzzling over the light reflected from this object.
The Spacecraft has taken hundreds of images to measure Ultima's brightness, but these latest measurements seem to conflict with a 2017 observation made when Ultima Thule covered (occulted) a star seen from Earth. The 2017 observation suggested that Ultima Thule may be not one, but two bodies that orbit each other. If there are no two objects there, the science team said in 2017, then this little Kuiper Belt object may have a pronounced elongated shape .
Now, scientists are not sure what to think, since repeated observations over the past three months have not revealed the variations in brightness that they would expect from two bodies or from a spinning elongated body. These variations in brightness are what scientists call a light curve . New Horizon chief investigator Alan Stern of the Southwest Research Institute (SwRI) in Boulder, Colorado, commented in a statement:
I call this Ultima's first puzzle – why does it have such a small light curve that we can't even detect It? I expect the detailed flying pictures will soon give us many more mysteries, but I didn't expect that, and so soon.
There are various possible explanations, including that Ultima Thule's rotation rod can target at or near incoming spaceships. Or Ultima Thule can be surrounded by a cloud of dust that conceals its light and makes the observations difficult to read. University of Virginia Anne Verbiscer, a researcher at New Horizon's assistant, proposed an even stranger opportunity:
Ultima [may be] surrounded by many small tumbling moons. If each month has its own light curve, they can together create a jumbled superposition of light curves that makes it look like new horizons that Ultima has a small light curve.
Although that explanation is likely, she added that it has no parallel in all other bodies in our solar system.
New Horizons will make their historical approach to Ultima Thule at 05:33 UTC (12:33) is EST; translate UTC to your time) January 1, 2019. Stern commented:
The spacecraft is now focused on the optimal airplane flight, over three times closer than we flew to Pluto. Ultima, here we come!
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For more information on New Horizon's mission, including fact sheets, schedules, video and images, visit http://www.nasa.gov/newhorizons and http: // pluto .jhuapl.edu.
Follow New Horizon's mission on Twitter and use hashtags #UltimaThule and #UltimaFlyby to join the conversation.
Live updates will also be available on the mission's Facebook page.
Bottom line: New Horizon's spacecraft has been given a "go" to be on the optimal path to Ultima Thule for its January 1, 2019 meeting.
Via Johns Hopkins here and here.