A NASA spacecraft is set to make a New Year's Day rendezvous with a tiny, icy world a billion miles farther than Pluto, in what would make it the most distant cosmic body ever explored by humankind. New Horizons was on course to fly past the mysterious, primitive object nicknamed Ultima Thule at 12:33am. Tuesday. The close encounter comes over 3 years after the probe's swing past Pluto, which until now was the farthest object visited by a spacecraft from Earth. This time, the drama was set to unfold more than 4 billion miles from Earth, so far away that it will be 10 hours before flight controllers find out whether the spacecraft survived the flyby. A few black-and-white pictures might be available within an hour or two of that official confirmation, but the highly anticipated close-up shots won't be ready until later Tuesday or Wednesday, in color, it is hoped.
New Horizons--the size of a baby grand piano--was expected to hurtle to within 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 success. Radio signals take over six hours to cover the distance to Earth. Scientists believe there should be no rings or moons around Ultima Thule that might endanger New Horizons. At a speed of 31,500 mph, New Horizons could easily be knocked out by a rice-sized particle. Ultima Thule was unknown until 2014, eight years after New Horizons departed Earth. It was discovered by the Hubble Space Telescope and added to New Horizons' itinerary.
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