Following the Bouncing Lander


OSIRIS_spots_PhilaeThis mosaic was assembled from a series of images captured by Rosetta’s OSIRIS camera taken over the half-hour spanning the first touchdown of the Philae lander Comet 67P/CG. The time of each of image is marked on the corresponding insets and is in UTC. A comparison of the touchdown area shortly before and after first contact with the surface is shown at the top.

The images were taken with the OSIRIS narrow-angle camera when the spacecraft was 17.5 km from the comet centre, or roughly 15.5 km from the surface. The enlarged insets cover a 17 x 17 m area.

From left to right, the images show Philae descending towards and across the comet before touchdown. The image taken after touchdown, at 15:43 GMT, confirms that the lander was moving east at a speed of about 0.5 m/s as it bounced across the surface of the comet.

Philae‘s actual final landing spot still hasn’t been found. After touching down and bouncing again at 17:25 UTC, it finally landed at 17:32. The mission imaging team believes that by combining the CONSERT ranging data with OSIRIS and navcam images from the orbiter and images from near the surface with data from Philae’s ROLIS and CIVA cameras they will be able to determine the lander’s whereabouts.

Image Credit: ESA

On the Surface of a Comet


Welcome_to_a_cometThe Rosetta mission lander is “safely” on the surface of its comet. One of Philae‘s feet can be seen at the bottom left of this picture of the surface of C67/P Churyumov-Gerasimenko. Philae bounced twice before settling and returning images from the surface, traveling a kilometer or so after ricocheting off of its desired target. A surface panorama suggests that the lander has come to rest tilted and near a shadowing wall. The lander’s solar panels are getting less illumination than if it had landed in the open. The science instruments are working as planned and data is being relayed when the main Rosetta spacecraft is above the lander’s new horizon. However, with good recharging from the solar array, the batteries will not last as long as had been hoped.

Image Credit: ESA

Philae-ing a Comet


Video Credit: ESA

NGC 4762


ngc 4762This is a disk galaxy seen almost perfectly edge on. The image from the Hubble Space Telescope shows us just how thin disk galaxies can be. NGC 4762, a galaxy in the nearby Virgo Cluster of Galaxies, is so thin that it is actually difficult to determine what type of disk galaxy it is. Its lack of a visible dust lane suggests that it is probably a low-dust lenticular galaxy, but it is still possible that a view from another angle would reveal spiral structure. The galaxy spans about 100,000 light years from end to end, with its center showing a slight bulge of stars. Most galaxies don’t appear this thin because our point of view from Earth doesn’t line up well enough with the planes of their thin galactic disks. However, galaxies this thin are common. Indeed, our own Milky Way Galaxy is thought to have roughly the same overall dimensions as NGC 4762.

Image Credit: NASA / ESA