Earth 's first probe to Pluto is beginning its long encounter with the icy world . It weighed 1,054 pounds ( 478 kilograms ) at launch . New Horizons will let us see the tiny planet for the first time ; it will arrive at Pluto in orbit .
Earth 's first probe to Pluto is beginning its long encounter with the icy world . New Horizons will let us see the tiny planet for the first time ; it will arrive at Pluto in orbit .