NASA's long-roaming Dawn today became the first spacecraft to orbit a dwarf planet, and the space agency is using the mission to test technology that may one day transport supplies for an outpost to shelter astronauts on Mars.
At 7:39 a.m. ET Friday, March 6, Dawn, which has traveled 3.1 billion miles, achieved orbit around Ceres, the largest object in the asteroid belt that lies between Mars and Jupiter, NASA said.
The spacecraft, which launched in September 2007, came within 38,000 miles of Ceres and was captured by the planet's gravity.
At 8:36 a.m., the space agency received a signal from Dawn indicating that its systems were healthy and working normally.
"Since its discovery in 1801, Ceres was known as a planet, then an asteroid and later a dwarf planet," wrote Marc Rayman, Dawn's chief engineer and mission director at NASA's Jet Propulsion Laboratory, in a blog post. "Now, after a journey of 3.1 billion miles and 7.5 years, Dawn calls Ceres, home."
Today's event is the second time the spacecraft has entered orbit around an extraterrestrial target, making Dawn the first spacecraft to orbit two objects.
Voyager 1, for instance, may have traveled to enter interstellar space and flown past planets in our solar system, but it has never entered another object's orbit, let alone leave one orbit to move on to another.
From 2011 to 2012, Dawn orbited and explored Vesta, the first asteroid to be visited by a spacecraft and the brightest asteroid in our sky.
The spacecraft, which uses two radiation-hardened RAD6000 processors, sent back images and data about Vesta, which is also in the asteroid belt between Mars and Jupiter. Dawn's work gave scientists a huge amount of information about the asteroid, which has a mountain two and a half times taller than Mount Everest and 90 canyons.
"Dawn's spectacular exploration of Vesta reveals a fascinating world that's more like a small planet than an asteroid," Rayman told Computerworld. "It's more like Earth than just a chunk of rock."
Now Dawn, which carries three scientific instruments, including a camera and a gamma ray detector, is focusing its sights on Ceres. It is looking for signs that the dwarf planet once had the conditions needed to support life.
So what has enabled Dawn to fly so far?
Rayman explained that the spacecraft, which measures 65 feet from one solar array wing tip to the other, uses an ion propulsion system that gives the spacecraft the thrust it needs. With a conventional propulsion system, Dawn and the rocket that launched it would have had to be much larger -- and more expensive -- to have even reached Vesta.
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