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Dawn spacecraft becomes first to orbit a Dwarf Planet: NASA

Xinhua, March 7, 2015 Adjust font size:

After a journey of 7.5 years, Dawn spacecraft settled into orbit Friday around the mini-planet Ceres, a dwarf planet never visited before, NASA said in a statement.

It marks the first time that a spacecraft has ever orbited two targets of the solar system.

"Confirmed: I am in orbit around #Ceres," Dawn said in a Twitter message.

The spacecraft, was approximately 61,000 kilometers from Ceres that lies in the asteroid belt between Mars and Jupiter when it was captured by the dwarf planet's gravity at about 4:39 a.m. PST (1239 GMT) Friday.

Mission controllers at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, received a signal from the spacecraft at 5:36 a.m. PST (1336 GMT) that Dawn was healthy and thrusting with its ion engine, the indicator Dawn had entered orbit as planned.

"Since its discovery in 1801, Ceres was known as a planet, then an asteroid and later a dwarf planet," said Marc Rayman, Dawn chief engineer and mission director at JPL in a statement. "Now, after a journey of 4.9 billion kilometers and 7.5 years, Dawn calls Ceres, home."

In addition to being the first spacecraft to visit a dwarf planet, Dawn also has the distinction of being the first mission to orbit two extraterrestrial targets.

The spacecraft, launched in 2007, previously explored the Vesta for more than a year, from 2011 to 2012, delivering new insights and thousands of images from that distant world. Ceres and Vesta are the two most massive residents of the solar system's main asteroid belt between Mars and Jupiter.

Ceres, with an average diameter of 950 km, is the largest object in the main asteroid belt between Mars and Jupiter. By comparison, Vesta has an average diameter of 525 km, and is the second most massive body in the belt.

Ceres is of great interest to astronomers and scientists, who believe that the small dwarf planet may also be a large water reservoir in the inner solar system aside from the Earth. However, scientists are unsure how much of that water is actually liquid.

"We feel exhilarated," said Chris Russell, principal investigator of the Dawn mission at the University of California, Los Angeles (UCLA). "We have much to do over the next year and a half, but we are now on station with ample reserves, and a robust plan to obtain our science objectives." Endite