After a nearly eight-year journey, a NASA spacecraft on Friday flawlessly slipped into orbit around Ceres in the first visit to a dwarf planet.
The robotic Dawn craft will circle the dwarf planet for more than a year, exploring its surface and unraveling its mysteries.
“It went exactly the way we expected. Dawn gently, elegantly slid into Ceres’ gravitational embrace,” said Marc Rayman, chief engineer for the $473 million mission managed by NASA’s Jet Propulsion Laboratory in Pasadena.
Ceres is the second and final stop for Dawn, which launched in 2007 on a voyage to the main asteroid belt, a zone between Mars and Jupiter that’s littered with rocky leftovers from the formation of the sun and planets some 4½ billion years ago.
Dawn will spend 16 months photographing the icy surface. It previously spent a year at Vesta exploring the asteroid and sending back stunning close-ups of its lumpy surface before cruising onto Ceres, the largest object in the asteroid belt.
The 3-billion mile trip was made possible by Dawn’s ion propulsion engines, which provide gentle yet constant acceleration and are more efficient than conventional thrusters.
As Dawn approached Ceres, it beamed back the best pictures ever taken of the dwarf planet. Some puzzling images revealed a pair of shiny patches inside a crater — signs of possible ice or salt.
Scientists hope to get a better glimpse of the spots when the spacecraft spirals closer to the surface. It’ll also study whether previously spotted plumes of water vapor continue to vent.
“There are a lot of secrets that will be revealed,” said mission scientist Lucy McFadden at NASA’s Goddard Space Flight Center in Maryland.
The spacecraft glided into place at 4:39 a.m. Friday and flight controllers received confirmation about an hour later. The maneuver occurred without a tense moment, unlike other captures that require braking to slow down.
“The real drama is exploring this alien, exotic world,” Rayman said.
Dawn is currently in Ceres’ shadows and won’t take new pictures until it emerges in April, he said.
Discovered in 1801, Ceres measures 600 miles across — as wide as Texas — and has a rocky core. It’s named after the Roman goddess of agriculture and harvest. It was initially called a planet before it was demoted to an asteroid and later classified as a dwarf planet.
Dwarf planets lately have become the focus of exploration. This summer, another NASA spacecraft — New Horizons — is set to make the first visit to Pluto, which was downgraded to dwarf planet.
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