NASA said last week that it has its spaceship New Horizons, the same craft with which humanity visited Pluto for the first time in 2015. The ship is still racing outward in our solar system. It is now approaching its next target, an object of the Kuiper Belt, located a billion miles beyond Pluto, called Ultima Thule. NASA said that after a three-week search, it found no visible obstacles in the optimal path of the spacecraft no rings, no small moons, no potential dangers. So New Horizons is now aligned with this optimal path for his encounter with Ultima Thule on January 1, 2019.
It will be another premiere of New Horizons, the farthest planetary flyby of human history.
And now we know that the spacecraft's path will be about 3,200 km from Ultima Thule instead of a bypass path that avoids the danger that would have driven it three times farther out. The last opportunity to maneuver the spacecraft on another trajectory was December 18th.
In the meantime, as New Horizons approaches Ultima Thule (officially designated the 2014 MU69), the mission's scientific team is puzzling over the reflected light object.
The spacecraft has taken hundreds of images to measure the brightness of Ultima, but these recent measurements seem to contradict a 2017 observation made when Ultima Thule viewed a star from Earth (hidden ) held. This observation from 2017 suggested that Ultima Thule could not be one but two bodies orbiting each other. If there are not two objects there, the science team said in 2017, then this small object on the Kuiper belt could have a pronounced oblong shape .
Now scientists are not sure what to think, because repeated observations over the past three months have not shown what brightness differences they would expect from two bodies or from a rotating elongated body. These brightness fluctuations call the scientists a light curve of . New Horizons senior investigator Alan Stern of the Southwest Research Institute (SwRI) in Boulder, Colorado commented on this in a statement:
I call the first mystery of the Ultima – why does it have such a tiny light curve that we do not even have can recognize it? I expect the detailed flyby images to provide many more secrets in the near future, but I did not expect this and so soon.
There are several possible explanations, including the fact that Ultima Thules spin poles can be aimed directly or close to the target incoming spacecraft. Or Ultima Thule may be surrounded by a cloud of dust that darkens the light and makes the observations hard to read. University of Virginia's Anne Verbiscer, Assistant to the New Horizons Assistance Project, suggested a still unknown option:
Ultima [may be] surrounded by many tiny monsters. If each moon has its own light curve, they could together create a jumbled overlay of light curves leading to New Horizons, as Ultima has a small light curve.
This explanation is plausible, she added, but it has no parallel in all other bodies of our solar system.
New Horizons will make a historical approach to Ultima Thule at 05:33 UTC (12:33) at the EST; Translate UTC to your time) on January 1, 2019. Stern comments:
The spacecraft is now aligned for optimal flyby, three times closer than we flew to Pluto. Ultima, here we come!
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For more information on the New Horizons mission, including leaflets, schedules, videos, and pictures, see: http://www.nasa.gov/newhorizons and http: // pluto .jhuapl.edu.
Follow the New Horizons mission on Twitter and use the hashtags #UltimaThule and #UltimaFly to join the conversation.
Live updates will also be available on the Mission Facebook page.
Conclusion: The New Horizons probe has given the starting signal to stay on the best path to Ultima Thule for their encounter on January 1, 2019.
About Johns Hopkins here and here.