'Dusk For Dawn': NASA's Only Mission To The Asteroid Belt Is Nearing Its End

After 11 years of trekking through a previously unexplored part of the inner solar system, the end is drawing near for NASA's Dawn mission.

The intrepid space probe has made history as the first spacecraft to venture inside the asteroid belt lying between the orbits of Mars and Jupiter.

There, Dawn gathered unique data on the two largest residents of the belt — the giant asteroid Vesta and the dwarf planet Ceres — thereby becoming the first-ever spacecraft to visit two extraterrestrial bodies during the same, albeit extended, mission.

During its remarkable journey through space, Dawn beamed back extraordinary photos of Vesta and Ceres, as well as a bounty of data that offered an unparalleled insight into the history and characteristics of the two alien worlds.

But the dauntless spacecraft, which uses a highly ingenious mode of transportation known as ion propulsion, is running out of fuel and is expected to completely deplete its hydrazine reserves sometime between September and October, NASA announced earlier today.

When this happens, Dawn will lose all means of getting in touch with Earth, as well as its ability to maintain its orientation — which is controlled by the space probe's hydrazine-fueled thrusters. This will leave Dawn suspended around Ceres, frozen in its final planned orbit, where the spacecraft can endure for at least another few decades.

NASA's Dawn spacecraft
3D illustration of the Dawn spacecraft approaching the dwarf planet Ceres.

Unlike the Cassini spacecraft, which met its end in the fiery embrace of Saturn's atmosphere, Dawn will not crash-land on its final flyby target. Since Ceres has no atmosphere, the only way to protect the dwarf planet — the only one in the inner solar system, as reported by the Inquisitr — from Earthly contamination is if Dawn never touches its surface.

Dawn Mission Highlights

Throughout its adventure inside the asteroid belt, the Dawn space probe has conquered previously unknown territories and has performed "unprecedented feats of spacecraft engineering," NASA officials said in a statement.

Its many achievements, one more impressive than the other, have made the mission team "intensely proud," according to Lori Glaze, acting director of the Planetary Science Division at NASA's Headquarters in Washington.

"Not only did this spacecraft unlock scientific secrets at these two small but significant worlds, it was also the first spacecraft to visit and orbit bodies at two extraterrestrial destinations during its mission. Dawn's science and engineering achievements will echo throughout history," Glaze pointed out.

The odyssey of the Dawn spacecraft started in September, 2007, when the space probe first soared to the heavens atop a Delta II-Heavy rocket launching from Cape Canaveral in Florida.

The first four years of its journey were spent traveling to Vesta, which it orbited for 14 months from 2011 to 2012. During this time, the Dawn mission mapped the entire asteroid from surface to core, collecting extensive data on its craters, canyons, and mountains.

After another two years of flying through the asteroid belt, Dawn set its sights on Ceres, where it arrived in 2015 and where it's still conducting science operations — and will continue to do so until all of its fuel is spent.

NASA's Dawn spacecraft
Artist's rendition of the Dawn spacecraft next to Vesta (left) and Ceres (right).

As the Inquisitr recently reported, the spacecraft made its closest approach to Ceres in late June, when Dawn came within 21 miles from its surface and snapped the closest-ever photo of the dwarf planet.

The spacecraft has also made momentous discoveries about the bright spots scattered over Ceres' surface, known as faculae and which eventually turned out to be massive salt deposits.

"The findings reinforce the idea that dwarf planets, not just icy moons like Enceladus and Europa, could have hosted oceans during their history — and potentially still do," notes NASA.

Another spectacular breakthrough of the Dawn mission was the realization that Ceres has abundant amounts of organic matter on its surface, the Inquisitr previously reported.

"Dawn's legacy is that it explored two of the last uncharted worlds in the inner Solar System," said Marc Rayman, Dawn mission director and chief engineer at of NASA's Jet Propulsion Laboratory in Pasadena, California. "Dawn has shown us alien worlds that, for two centuries, were just pinpoints of light amidst the stars. And it has produced these richly detailed, intimate portraits and revealed exotic, mysterious landscapes unlike anything we've ever seen."