December 4, 2013
NASA Releases Schedule Details For Dawn Mission
Brett Smith for redOrbit.com - Your Universe Online
NASA officials have just announced the schedule for the spacecraft Dawn’s approach and activities at the dwarf planet Ceres, the largest object in the asteroid belt between Jupiter and Mars.The NASA probe is slated to arrive at Ceres in late March or the beginning of April 2015 – 30 months after investigating a similar proto-planet called Vesta.
"Our flight plan around Ceres will be choreographed to be very similar to the strategy that we successfully used around Vesta," said Bob Mase, the project manager for Dawn. "This approach will build on that and enable scientists to make direct comparisons between these two giants of the asteroid belt."
Space agency officials said they plan to perform approach operations in late January 2015. In February 2015, Ceres will be visible from Dawn. At that point, the probe will take images and send them back to Earth for use in the navigation process. Ceres' gravity will capture the probe a little more than a month later.
Later in April, Dawn will make its first complete, albeit preliminary, characterization of Ceres from an altitude of about 8,400 miles above the surface. Next, it is scheduled to drop down to an altitude of nearly 2,800 miles to obtain a global view of Ceres with Dawn's framing camera and global maps using its visible and infrared mapping spectrometer (VIR).
In August 2015, Dawn is scheduled to drop down to an altitude of about 920 miles, also known as a high-altitude mapping orbit. During this stage, the spacecraft will continue to use the VIR and framing camera, but at higher resolutions than in the earlier survey phase. The spacecraft will also capture stereo images to capture the surface of Ceres in 3-D.
In late November, Dawn will begin its closest orbit around Ceres at a distance of just over 230 miles. NASA will set its probe at this low-altitude mapping orbit to record data with its gamma ray and neutron detector (GRaND). GRaND is designed to detect signatures of the elements on and near the object’s surface. The craft will also conduct a gravity experiment designed to measure the pull of the dwarf planet.
NASA officials said they have inserted extra days into the schedule to account for the various uncertainties.
"We are expecting changes when we get to Ceres and, fortunately, we built a very capable spacecraft and developed flexible plans to accommodate the unknowns," said Marc Rayman, Dawn's chief engineer and mission director. "There's great excitement in the unexpected - that's part of the thrill of exploration."
"This transition makes us eager to see what secrets Ceres will reveal to us when we get up close to this ancient, giant, icy body," said Christopher Russell, Dawn's principal investigator. "While Ceres is a lot bigger than the candidate asteroids that NASA is working on sending humans to, many of these smaller bodies are produced by collisions with larger asteroids such as Ceres and Vesta.”
“It is of much interest to determine the nature of small asteroids produced in collisions with Ceres,” Russel added. “These might be quite different from the small rocky asteroids associated with Vesta collisions."