NASA spacecraft Dawn first to orbit dwarf planet Ceres

A NASA spacecraft for the first time has arrived at a dwarf planet to begin a 16-month exploration.

Thia NASA image obtained March 6, 2015 shows Ceres, taken by the Dawn spacecraft on March 1, just a few days before the mission achieved orbit around the previously unexplored world. The image shows Ceres as a crescent, mostly in shadow because the spacecraft's trajectory put it on a side of Ceres that faces away from the sun until mid-April. When Dawn emerges from Ceres' dark side, it will deliver ever-sharper images as it spirals to lower orbits around the planet. The image was obtained at a distance of about 30,000 miles (about 48,000 kilometers) at a sun-Ceres-spacecraft angle, or phase angle, of 123 degrees. Image scale on Ceres is 1.9 miles (2.9 kilometers) per pixel. Ceres has an average diameter of about 590 miles (950 kilometers). The probe will stay over the mysterious body for sixteen months to better study its structure and gather clues to help mankind better understand how the planets were created. AFP PHOTO/NASA/JPL-CALTECH/UCLA/MPS/DLR/IDA/HANDOUT = RESTRICTED TO EDITORIAL USE / MANDATORY CREDIT: "AFP PHOTO HANDOUT-NASA/JPL-CALTECH/UCLA/MPS/DLR/IDA"/ NO MARKETING - NO ADVERTISING CAMPAIGNS/ – NO A LA CARTE SALES / DISTRIBUTED AS A SERVICE TO CLIENTS / =

A NASA spacecraft for the first time has arrived at a dwarf planet to begin a 16-month exploration.

The space agency has confirmed that the Dawn craft entered orbit around Ceres in the asteroid belt between Mars and Jupiter.

“It went exactly the way we expected. Dawn gently, elegantly slid into Ceres’ gravitational embrace,” said mission chief engineer Marc Rayman at NASA’s Jet Propulsion Laboratory, which manages the $473 million mission.

Ceres is the last and final stop for Dawn, which launched in 2007 on a voyage to the main asteroid belt, a zone littered with rocky leftovers from the formation of the sun and planets some 4.5 billion years ago.

Dawn will spend the next 16 months photographing the icy surface. It previously spent a year at Vesta exploring the asteroid and sending back stunning close-ups of the lumpy surface before cruising onto the Texas-sized Ceres, the largest object in the asteroid belt.

NASA pic ... The dwarf planet Ceres, taken by the space agency's Dawn spacecraft, in February. Picture: AP

The 5-billion-kilometre 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 had beamed back puzzling images revealing a pair of shiny patches inside a crater — signs of possible ice or salt.

Scientists hope to get a better glimpse when the spacecraft spirals closer to the surface to study whether previously spotted plumes of water vapour continue to vent.

Dawn is currently in Ceres’ shadows and won’t take new pictures until it emerges in April, Rayman said.

“The real drama is exploring this alien, exotic world,” he said.

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 demoted to dwarf planet.

Dawn almost never made it out to the inner solar system. The mission endured funding-related project cancellations and launch delays before it received the green light to fly.