Nasa said last week it has taken a step back to the New Horizons spacecraft, the same craft that made the first visit of humanity to Pluto in 2015. The spacecraft is still accelerating in our solar system. Now it is approaching the next target, an object of the Kuiper Belt a billion kilometers beyond Pluto, nicknamed Ultima Thule. NASA said that – after a three-week search – it found no apparent obstacles in the spacecraft's probe. great way, without rings, without small moons, without potential risks. Thus, New Horizons is now on the right track for their January 1, 2019 encounter with Ultima Thule.
It will be another novelty for the New Horizons, the most distant planetary flight in human history.
And now we know that the spacecraft's path will take about 2,200 miles (3,500 km) of Ultima Thule, instead of a diversion to avoid dangers that would have pushed three times further. The last chance to maneuver the spacecraft into another trajectory was December 18.
Meanwhile, as New Horizons approaches the Ultima Thule (which is officially designated as 2014 MU69), the mission's scientific team is intrigued by the light reflected by that object.
The spacecraft has taken hundreds of images to measure Ultima's brightness, but these recent measurements appear to be at odds with a 2017 observation made when Ultima Thule covered (concealed) a star seen from Earth. This observation of 2017 suggested that Ultima Thule could be not one but two bodies orbiting around them. If there are not two objects there, the science team said in 2017, then this little object of the Kuiper Belt may have a pronounced elongated form.
Now scientists are not sure what to think, since repeated observations over the past three months have not revealed the brightness variations they would expect from two bodies, or an elongated body spinning. These brightness variations are what scientists call light curve. New Horizons principal investigator Alan Stern of the Southwest Research Institute (SwRI) in Boulder, Colo. Commented in a statement:
I call this the Ultima Ultima's puzzle – why does it have such a small light curve that we can not even detect it? I hope the detailed images of flyovers will soon bring us much more mystery, but I did not expect this and so soon.
There are a number of possible explanations, including that the Ultima Thule's spinning post can be directed to or near the spacecraft. Or Ultima Thule may be surrounded by a cloud of dust that obscures its light and makes it difficult to read the observations. Anne Verbiscer of the University of Virginia, New Horizons assistant scientist, suggested an even stranger possibility:
Last [may be] surrounded by many small moons falling. If each moon has its own curve of light, then together they could create a confused superposition of light curves that make it look at New Horizons as Ultima has a small curve of light.
Although this explanation is also plausible, she added, it is unparalleled in all other bodies of our solar system.
New Horizons will make its historic approach to Ultima Thule at 05:33 UTC (12:33 EST, translate UTC for its time) on January 1, 2019. Stern commented:
The spacecraft is now directed to the ideal overfly, more than three times closer than we flew to Pluto. Ultima, here we go!
EarthSky's lunar calendars are cool! They make great gifts. Ask for it now. Going fast!
For more information on the New Horizons mission, including fact sheets, times, videos, and pictures, visit: http://www.nasa.gov/newhorizons and http://pluto.jhuapl.edu.
Follow the New Horizons mission in Twitter and use the hashtags #UltimaThule and #UltimaFlyby to join the conversation.
Live updates will also be available on the mission page on Facebook.
Conclusion: The New Horizons spacecraft received a "go" to stay on the right path to Ultima Thule in its January 1, 2019 encounter.
Via Johns Hopkins here and here.