NASA's Dawn spacecraft has provided the closest-yet views of Ceres, mapping its features in unprecedented detail, including the 6 km high 'pyramid' spotted on the dwarf planet. "Dawn is performing flawlessly in this new orbit as it conducts its ambitious exploration," said Marc Rayman, Dawn's chief engineer and mission director, based at NASA's Jet Propulsion Laboratory, Pasadena, California. "The spacecraft's view is now three times as sharp as in its previous mapping orbit, revealing exciting new details of this intriguing dwarf planet," he said.
The new image of the 'pyramid', taken from around 1,470 kilometres away, shows its conical shape and a series of bright streaks on its surface. The image was taken on August 19, 2015. The spacecraft also imaged a mountain ridge that lies in the centre of Urvara crater on Ceres. The crater's diameter is 163 kilometres. Another photo of the Gaue crater, a large crater on Ceres, shows the centre of this crater is sunken in. Its diameter is 84 kilometres.
Its perimeter is sharply defined, with almost no accumulated debris at the base of the brightly streaked slope
At its current orbital altitude of 1,470 kilometres, Dawn takes 11 days to capture and return images of Ceres' whole surface. Each 11-day cycle consists of 14 orbits. Over the next two months, the spacecraft will map the entirety of Ceres six times. The spacecraft is using its framing camera to extensively map the surface, enabling 3-D modelling. Every image from this orbit has a resolution of 450 feet per pixel, and covers less than 1 per cent of the surface of Ceres. At the same time, Dawn's visible and infrared mapping spectrometer is collecting data that will give scientists a better understanding of the minerals found on Ceres' surface.
Engineers and scientists will also refine their measurements of Ceres' gravity field, which will help mission planners in designing Dawn's next orbit - its lowest - as well as the journey to get there. In late October, Dawn will begin spiralling toward this final orbit, which will be at an altitude of 375 kilometres. Dawn is the first mission to visit a dwarf planet, and the first to orbit two distinct solar system targets. It orbited protoplanet Vesta for 14 months in 2011 and 2012, and arrived at Ceres on March 6, 2015.
