Previously, NASA planned to lower the closest approach to Ceres [wikipedia.org] of the Dawn spacecraft to around 120 miles (200 km) from 239 miles (385 km). Now, the XMO7 orbit [nasa.gov] will reach an altitude of just 22 miles (35 km) above Ceres. The images returned should be over 9000 times better than what Hubble can capture. This is the final orbit planned [nasa.gov]:
NASA's Dawn spacecraft is maneuvering to its lowest-ever orbit for a close-up examination of the inner solar system's only dwarf planet.
In early June, Dawn will reach its new, final orbit above Ceres. Soon after, it will begin collecting images and other science data from an unprecedented vantage point. This orbit will be less than 30 miles (50 kilometers) above the surface of Ceres -- 10 times closer than the spacecraft has ever been.
Dawn will collect gamma ray and neutron spectra, which help scientists understand variations in the chemical makeup of Ceres' uppermost layer. That very low orbit also will garner some of Dawn's closest images yet.
The transfer from Dawn's previous orbit to its final one is not as simple as making a lane change. Dawn's operations team worked for months to plot the course for this second extended mission of the veteran spacecraft, which is propelled by an ion engine. Engineers mapped out more than 45,000 possible trajectories before devising a plan that will allow the best science observations.
Previously: Dawn Mission Extended at Ceres [soylentnews.org]
Related: Ceres May Have Had a Global Surface Ocean in the Past [soylentnews.org]
Evidence of a Seasonal Water Cycle and Surface Changes Found on Ceres [soylentnews.org]