NASA's Dawn Mission has completed its High Altitude Mapping Orbit (HAMO) survey mission of dwarf planet Ceres, and is sending data back to Earth. The Dawn Twitter feed posts announcements and new images frequently.
I have completed my #Ceres mapping campaign at my current altitude! Beaming data back now; will start descending later this week.
— NASA's Dawn Mission (@NASA_Dawn) October 21, 2015
Later this year, the spacecraft it will spiral down from it's current altitude of 1,470 km (915 mi) to its fourth and final orbital altitude at about 375 km (230 mi) above Ceres; it will take two months to descend to this new Low Altitude Mapping Orbit (LAMO).
Once at its LAMO, Dawn will record spectra of visible & infrared light, neutrons & gamma rays, and measure the distribution of mass inside Ceres. And take pictures... lots and LOTS of pictures. Maybe then, we'll finally know what those bright spots in Occator crater are.
Next year, the spacecraft's supply of hydrazine will likely be exhausted, and the mission will come to an end. “Planetary protection” protocols require that the Dawn spacecraft may not reach the dwarf planet's surface for at least 50 years after its arrival; Dawn's orbit around Ceres will remain relatively stable for perhaps millennia.
The Dawn mission is a personal favorite of mine; my first lecture as a volunteer NASA/JPL Solar System Ambassador was given to the Warren Astronomical Society - about the Dawn mission at asteroid Vesta. I get very excited and animated when I discuss this mission!