page_title: Dawn (spacecraft)
section_title: Ceres orbit
hierarchical_section_title: Dawn (spacecraft) / Mission summary / Ceres orbit
caption_attribution_description: English: Animation of Dawn's trajectory around Ceres from 1 February 2015 to 6 October 2018 &#160;&#160;&#160;&#160;&#160;&#160;Dawn&#160;· &#160;&#160;&#160;&#160;&#160;&#160;Ceres
context_page_description: Dawn is a retired space probe launched by NASA in September 2007 with the mission of studying two of the three known protoplanets of the asteroid belt, Vesta and Ceres. It was retired on November 1, 2018, and it is currently in an uncontrolled orbit around its second target, the dwarf planet Ceres. Dawn is the first spacecraft to orbit two extraterrestrial bodies, the first spacecraft to visit either Vesta or Ceres, and the first to orbit a dwarf planet, arriving at Ceres in March 2015, a few months before New Horizons flew by Pluto in July 2015.
  Dawn entered orbit around Vesta on July 16, 2011, and completed a 14-month survey mission before leaving for Ceres in late 2012. It then entered orbit around Ceres on March 6, 2015. NASA considered, but decided against, a proposal to visit a third target. On October 19, 2017, NASA announced that the mission would be extended until the probe's hydrazine fuel supply was used up. On November 1, 2018, NASA announced that the Dawn spacecraft had finally exhausted all of its hydrazine fuel, thus ending its mission. The satellite is currently in an uncontrolled state about Ceres.
context_section_description: Dawn entered Ceres orbit on March 6, 2015, four months prior to the arrival of New Horizons at Pluto. Dawn thus became the first mission to study a dwarf planet at close range. Dawn initially entered a polar orbit around Ceres, and continued to refine its orbit. It obtained its first full topographic map of Ceres during this period.
  From April 23 to May 9, 2015, Dawn entered an RC3 orbit (Rotation Characterization 3) at an altitude of 13,500 km (8,400 mi). The RC3 orbit lasted 15 days, during which Dawn alternated taking pictures and sensor measurements and then relayed the resulting data back to Earth. On May 9, 2015, Dawn powered its ion engines and began a month-long spiral descent down to its second mapping point, a Survey orbit, three times closer to Ceres than the previous orbit. The spacecraft stopped twice to take images of Ceres during its spiral descent into the new orbit.
  On June 6, 2015, Dawn entered the new Survey orbit at an altitude of 4,430 km (2,750 mi). In the new Survey orbit, Dawn circled Ceres every three Earth days. The Survey phase lasted 22 days (7 orbits), and was designed to obtain a global view of Ceres with Dawn's framing camera, and generate detailed global maps with the visible and infrared mapping spectrometer (VIR).
  On June 30, 2015, Dawn experienced a software glitch when an anomaly in its orientation system occurred. It responded by going into safe mode and sending a signal to engineers, who fixed the error on July 2, 2015.  Engineers determined the cause of the anomaly to be related to the mechanical gimbal system associated with one of Dawn's ion engines.  After switching to a separate ion engine and conducting tests from July 14 through July 16, 2015, engineers certified the ability to continue the mission.
  On August 17, 2015, Dawn entered the HAMO orbit (High-Altitude Mapping Orbit). Dawn descended to an altitude of 1,480 km (920 mi), where in August 2015 it began the two-month HAMO phase. During this phase, Dawn continued to acquire near-global maps with the VIR and framing camera at higher resolution than in the Survey phase. It also imaged in stereo to resolve the surface in 3D.
  On October 23, 2015, Dawn began a two-month spiral toward Ceres to achieve a LAMO orbit (Low-Altitude Mapping Orbit) at a distance of 375 km (233 mi). Since reaching this fourth orbit in December 2015, Dawn was scheduled to acquire data for the next three months with its gamma-ray and neutron detector (GRaND) and other instruments that identified the composition at the surface.
  Having surpassed its mapping objectives, Dawn climbed to its fifth science orbit of 1,460 km (910 mi) beginning on September 2, 2016, to complete additional observations from a different angle. Dawn began raising its altitude to its sixth science orbit of 7,200 km (4,500 mi) on November 4, 2016, with a goal of reaching it by December 2016. The return to a higher altitude allowed for a second set of data at this altitude, which improves the overall science quality when added to the first batch. However, this time the spacecraft was placed where it was not spiraling and was orbiting in the same direction as Ceres, which reduced propellant consumption.
caption: Animation of Dawn's trajectory around Ceres from February 1, 2015 to October 6, 2018
     Dawn ·   Ceres