Category Archives: Comets and Asteroids
The first attempt by ESA and Rosetta to hear back from Philae has turned up only radio silence – but that doesn’t necessarily mean the lander is on permanent shutdown. It may just be that it’s still too cold and dark where Philae is to have sufficiently warmed up its components for reactivation.
“It was a very early attempt; we will repeat this process until we receive a response from Philae,” said DLR (Germany’s Aerospace agency) Project Manager Stephan Ulamec. “We have to be patient.”
After landing in an as yet unconfirmed location on comet 67P on November 12, 2014, Philae performed all of its primary science tasks before running out of battery power and entering a hibernation “safe” mode. Its reawakening is anticipated by mission engineers as the comet gets closer to the Sun over the next several months.
It’s official – NASA’s Dawn spacecraft has arrived at the dwarf planet Ceres! Today, March 6 2015, at 7:39 a.m. EST (12:39 UTC) Dawn was captured by Ceres’ gravity at a distance of 38,000 miles (61,155 km). Mission controllers at JPL received a signal from the spacecraft at 8:36 a.m. EST (13:36 UTC) that Dawn was healthy and thrusting with its ion engine, indicating Dawn had entered orbit as planned.
Over the next several weeks Dawn will move into a lower orbit around Ceres, making observations along the way.
Dawn is the first spacecraft to successfully enter orbit around two worlds* and the first to orbit a dwarf planet. Its first target was the asteroid Vesta, which it orbited from July 2011 to September 2012. Now at Ceres two and a half years later, it will remain in orbit both during its primary science phase and beyond… Ceres will be Dawn’s permanent home.
“Since its discovery in 1801, Ceres was known as a planet, then an asteroid and later a dwarf planet. Now, after a journey of 3.1 billion miles and 7.5 years, Dawn calls Ceres home.”
– Marc Rayman, Mission Director and Dawn chief engineer
Congratulations Dawn and the mission team! Follow the Dawn mission news here (and of course right here on Lights in the Dark!)
*The two worlds, Vesta and Ceres, are separate targeted worlds of a science mission. This does not include time spent orbiting Earth, for this mission or others, prior to departure burn.
See the image above? It’s the surface of a comet. Pretty cool. See the dark spot along the bottom? It’s the shadow of the spacecraft that took the image of the comet.
NASA’s Dawn spacecraft is just a few days away from getting snagged by the pull of Ceres, a dwarf planet existing amongst the asteroids. As it’s approaching via the slow but steady thrust of its ion engines Dawn is getting better and better images of Ceres, bringing the world’s features into focus. But on Friday, March 6 (at 7:20 a.m. EST / 12:20 UTC) it will finally feel the gentle tug of Ceres’ gravity and will soon become the first spacecraft to enter orbit around two different targets.
“Dawn is about to make history,” said Robert Mase, project manager for the Dawn mission at NASA’s Jet Propulsion Laboratory in Pasadena, California. “Our team is ready and eager to find out what Ceres has in store for us.”
One of the biggest mysteries that has arisen during Dawn’s approach to Ceres is the true identity of the two bright spots located within a crater on its northern hemisphere. Shining like the eyes of some nocturnal creature, the bright region was first seen in Hubble images captured in December 2003. Now Dawn has gotten close enough to resolve it into two separate spots, one brighter than the other… but not much more is known about its true nature yet. Read the rest of this entry
Here’s your weekly Ceres update! The dwarf planet’s features are coming into better and better focus for the approaching Dawn spacecraft, which will be captured by Ceres’ gravity on March 6. The image above is yet another “best-ever” of Ceres (as will be each one we see now), captured on Feb. 19, 2015, from a distance of about 29,000 miles (46,000 km).
This was one of a trio of images from Dawn released today. The others can be seen below, including one that shows the intriguing bright spot that has been observed for over a decade.
On Saturday, Feb. 14, 2015, the Rosetta spacecraft performed a bit of a barnstorming act, swooping low over the surface of comet 67P/C-G in the first dedicated close pass of its mission. It came within a scant 6 km (3.7 miles) of the comet’s surface at 12:41 GMT. The image above is a mosaic of four individual NavCam images acquired just shortly afterwards, when Rosetta was about 8.9 km from the comet.
Higher-resolution OSIRIS images should be downlinked from the spacecraft within the next few days.
The view above looks across much of the Imhotep region along the flat bottom of comet 67P’s larger lobe. (See a map of 67P’s named regions here.) At the top is the flat “plain” where the Cheops boulder cluster can be seen – the largest of which, Cheops itself, is 45 meters (148 feet) across.
After the close pass Rosetta headed out to a distance of about 253 km (157 miles) before beginning preparations to approach closer again. Over the course of Rosetta’s mission this year flybys will be the “new normal,” but none will be as close as the Feb. 14 pass.
Watch a video from ESA about the close pass below, and find more images from the flyby in my article on Universe Today here.