Assuming the mission succeeded – and we'll know in a few hours – New Horizons made an historic flyby of the farthest, and quite possibly the oldest, cosmic body ever explored by humankind.

This artist's illustration shows the New Horizons spacecraft encountering 2014 MU69 nicknamed Ultima Thule.
This artist's illustration shows the New Horizons spacecraft encountering 2014 MU69 nicknamed Ultima Thule.
(AP)
The NASA spacecraft New Horizons that yielded the first close-up views of Pluto opened the new year on Tuesday at an even more distant world, a billion miles beyond.
Flight controllers said everything looked good for New Horizons' flyby of the tiny, icy object at 12:33 am Tuesday (0533 GMT). Confirmation won't come for hours, though, given the vast distance.
The mysterious, ancient target nicknamed Ultima Thule is 6.4 billion kilometres (4 billion miles) from Earth.
Scientists wanted New Horizons observing Ultima Thule during the encounter, not phoning home. So they have to wait until late morning (in the US) before learning whether the spacecraft survived.

Highly anticipated close-ups soon With New Horizons on autopilot, Mission Control was empty on Monday night at Johns Hopkins University's Applied Physics Laboratory in Laurel, Maryland. 
Instead, hundreds of team members and their guests gathered nearby on campus for back-to-back countdowns.
The crowd ushered in 2019 at midnight, then cheered, blew party horns and jubilantly waved small US flags again 33 minutes later, the appointed time for New Horizons' closest approach to Ultima Thule.
A few black-and-white pictures of Ultima Thule might be available following Tuesday's official confirmation, but the highly anticipated close-ups won't be ready until Wednesday or Thursday, in colour, it is hoped.

A press conference prior to the flyby of Ultima Thule by the New Horizons spacecraft at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, US December 31, 2018.
A press conference prior to the flyby of Ultima Thule by the New Horizons spacecraft at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, US December 31, 2018.
(Reuters)
'We're a billion miles farther than Pluto' "We set a record. Never before has a spacecraft explored anything so far away," said the project's lead scientist who led the countdown to the close encounter, Alan Stern of Southwest Research Institute.
"Think of it. We're a billion miles farther than Pluto."
Stern called it an auspicious beginning to 2019, which will mark the 50th anniversary of Neil Armstrong and Buzz Aldrin's footsteps on the moon in July 1969.
"Ultima Thule is 17,000 times as far away as the 'giant leap' of Apollo's lunar missions," Stern noted in an opinion piece inThe New York Times.
New Horizons, which is the size of a baby grand piano and part of an $800 million mission, was expected to hurtle to within 3,500 kilometres (2,200 miles) of Ultima Thule, considerably closer than the Pluto encounter of 2015.
Its seven science instruments were to continue collecting data for four hours after the flyby. Then the spacecraft was to turn briefly toward Earth to transmit word of its success.
It takes over six hours for radio signals to reach Earth from that far away.Source: trtworld.com