The NASA spacecraft New Horizons performed an historic, close-up flyby of the dwarf planet Pluto on Tuesday, after a 3 billion-mile journey that took nearly 10 years.
The New Horizons mission led by the Johns Hopkins University Applied Physics Laboratory and the National Aeronautics & Space Administration, has completed humankind’s robotic tour of the solar system: Spacecraft have now visited every planet.
Team scientists confirmed that New Horizons had collected the intended images and spectra during its close encounter of some 7,750 miles above Pluto’s surface. The craft is now speeding away from Pluto, but over the next 16 months will send back to Earth the data it took during the relatively brief flyby.
NASA planned a flyby instead of an orbiting mission around Pluto because the dwarf planet is so small—even smaller than Earth’s moon—and because its weak gravity would have required too much fuel, both costly and heavy, to keep the craft in orbit.
At a Tuesday briefing, John Grunsfeld, NASA’s associate administrator, told members of the media to expect spectacular new images beginning on Wednesday. The images should tell scientists more about Pluto’s surface composition and geology.
Telescopes, including NASA’s Hubble Space Telescope, have never been able to observe Pluto as much more than a smudgy ball. But recent images taken by as it approached Pluto show a detailed surface with a curious two-toned heart-shaped area. This large area is relatively unmarked by craters, which scientists suggest could mean Pluto has an active geology that produces smooth material that coats the surface.
New Horizons has also collected images of Pluto’s large moon, Charon, and its other smaller moons. A recent image of Charon shows an area on the north polar cap that is likely covered in sticky red-brown hydrocarbons, or tholins.
“I can’t express how it feels to have achieved a childhood dream of space exploration,” NASA’s Alice Bowman, missions operations manager, said to the exuberant audience at the briefing. “Tell your children, ‘Do what you’re passionate about.’ ”