NASA space probe 'phones home' in landmark mission to solar system's edge

NASA’s New Horizons explorer successfully “phoned home” on Tuesday after a journey to the most distant world ever explored by humankind, a frozen rock at the edge of the solar system that scientists hope will uncover secrets to its creation. 

The nuclear-powered space probe has travelled 4 billion miles (6.4 billion km) to come within 2,200 miles (3,540 km) of Ultima Thule, an apparently peanut-shaped, 20-mile-long (32-km-long) space rock in the uncharted heart of the Kuiper Belt. The belt is a ring of icy celestial bodies just outside Neptune’s orbit. 

Engineers at Johns Hopkins Applied Physics Laboratory in Maryland cheered when the spacecraft’s first signals came through the National Aeronautic and Space Agency’s Deep Space Network at 10:28 am.  “We have a healthy spacecraft,” Mission Operations Manager Alice Bowman declared. 

The spacecraft will ping back more detailed images and data from Thule in the coming days, NASA said.   

Launched in January 2006, New Horizons embarked on its 4 billion-mile journey toward the solar system’s edge to study the dwarf planet Pluto and its five moons. 

“Last night, overnght, the United States spacecraft New Horizons conducted the farthest exploration in the history of humankind, and did so spectacularly,” New Horizons principal investigator Alan Stern told a news conference at the Johns Hopkins facility in Laurel, Maryland. 

An image of Thule, sent overnight and barely more detailed than previous images, deepens the mystery of whether Thule is a single rock shaped like an asymmetrical peanut or actually two rocks orbiting each other, “blurred together because of their proximity,” Stern said. 

During a 2015 fly-by, the probe found Pluto to be slightly larger than previously thought.