New Horizons completes flyby of Ultima Thule


New Horizons completes flyby of Ultima Thule

Bryan Dyne

4 January 2019

NASA’s New Horizons spacecraft successfully completed its flyby of the Kuiper Belt object, informally known as Ultima Thule, in the early hours of New Year’s Day 2019. The probe broke off contact with Earth in the 24 hours before closest approach in order to perform its primary scientific investigations and reestablished communications 10 hours afterwards, to the jubilation of its controllers and people worldwide.

The first high resolution of Ultima Thule. Credit: NASA/JHUAPL/SWRI

Ultima Thule is 6.4 billion kilometers from Earth (about 2 billion kilometers more distant than Pluto), the most distant astronomical body ever explored up close by a vehicle launched from our planet. This record was previously set when New Horizons flew past Pluto in July 2016 and one that will hopefully be broken by further New Horizons missions in this remote part of the Solar System. It is also the smallest asteroid to be visited by one of humanity’s robotic explorers.

All data received by the spacecraft so far indicates that every instrument performed as expected and that every system is healthy. Downloads from the spacecraft are currently paused as it passes behind the Sun as seen from Earth. On January 10 it will begin beaming back the full set of data collected and continue for a further 20 months as the data is slowly and steadily beamed back to scientists on the ground. The most high-resolution images will be sent first, followed by other data, including particle and magnetic field densities far away from the Sun.

Unlike virtually every other target for a close encounter with a manmade spacecraft, Ultima Thule was only selected for a flyby after New Horizons was launched. In the years preceding the…

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