Four years and 117 million miles later, NASA's Dawn spacecraft has finally reached its landing point: the asteroid Vesta.
The space agency said the spacecraft has begun to orbit the asteroid. The asteroid's gravity is will be able to capture the spacecraft into orbit. This is unlike many other spacecraft missions, where a propulsive burn does the trick.
The asteroid lies in the main belt between the orbits of Mars and Jupiter. Once Vesta captured Dawn into is direct orbit, the spacecraft sat 9,900 miles away from the asteroid. From this distance, Dawn will study Vesta's surface.
It has taken nearly four years to get to this point, Robert Mase, Dawn project manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif, said in a statement. Our latest tests and check-outs show that Dawn is right on target and performing normally.
NASA says the spacecraft will take one year to study Vesta. The information collected by Dawn will help scientists understand the earliest chapter of our solar system's history.
Dawn's journey began back in September of 2007. Since then, engineers from the JPL ave been subtly shaping its trajectory. They goal is to get Dawn's orbit around Vesta to match Vesta's orbit around the sun.
The engineers have experienced bumps along the way. As recently as a week ago, Dawn experienced a loss of thrust. The engineers accounted it to an electronic circuit in the spacecraft's digital control and interface unit, a subsystem that houses the circuit and a computer that provides the brains to Dawn's ion propulsion system.
Once Dawn is finished with Vesta it will launch for its second mission where it will head to the dwarf planet Ceres. Like the asteroid Vesta, Ceres will be able to help scientists understand the early formations of the solar system.
By studying both these two distinct bodies with the same complement of instruments on the same spacecraft, the Dawn mission hopes to compare the different evolutionary path each took as well as create a picture of the early solar system overall, NASA said on its Dawn website.
Once it does this, it will become the first spacecraft to orbit two solar system destinations beyond Earth. Dawn will eventually be finished with its mission in 2017.
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