[meteorite-list] Dawn Mission Extended at Ceres

[Ron Baalke]

https://www.jpl.nasa.gov/news/news.php?feature=6980

Dawn Mission Extended at Ceres
Jet Propulsion Laboratory
October 19, 2017

NASA has authorized a second extension of the Dawn mission at Ceres, the 
largest object in the asteroid belt between Mars and Jupiter. During this 
extension, the spacecraft will descend to lower altitudes than ever before 
at the dwarf planet, which it has been orbiting since March 2015. The 
spacecraft will continue at Ceres for the remainder of its science investigation 
and will remain in a stable orbit indefinitely after its hydrazine fuel 
runs out.

The Dawn flight team is studying ways to maneuver Dawn into a new elliptical 
orbit, which may take the spacecraft to less than 120 miles (200 kilometers) 
from the surface of Ceres at closest approach. Previously, Dawn's lowest 
altitude was 240 miles (385 kilometers).

A priority of the second Ceres mission extension is collecting data with 
Dawn's gamma ray and neutron spectrometer, which measures the number and 
energy of gamma rays and neutrons. This information is important for understanding 
the composition of Ceres' uppermost layer and how much ice it contains.

The spacecraft also will take visible-light images of Ceres' surface geology 
with its camera, as well as measurements of Ceres' mineralogy with its 
visible and infrared mapping spectrometer.

The extended mission at Ceres additionally allows Dawn to be in orbit 
while the dwarf planet goes through perihelion, its closest approach to 
the Sun, which will occur in April 2018. At closer proximity to the Sun, 
more ice on Ceres' surface may turn to water vapor, which may in turn 
contribute to the weak transient atmosphere detected by the European Space 
Agency's Herschel Space Observatory before Dawn's arrival. Building on 
Dawn's findings, the team has hypothesized that water vapor may be produced 
in part from energetic particles from the Sun interacting with ice in 
Ceres' shallow surface.Scientists will combine data from ground-based 
observatories with Dawn's observations to further study these phenomena 
as Ceres approaches perihelion.

The Dawn team is currently refining its plans for this next and final 
chapter of the mission. Because of its commitment to protect Ceres from 
Earthly contamination, Dawn will not land or crash into Ceres. Instead, 
it will carry out as much science as it can in its final planned orbit, 
where it will stay even after it can no longer communicate with Earth. 
Mission planners estimate the spacecraft can continue operating until 
the second half of 2018.

Dawn is the only mission ever to orbit two extraterrestrial targets. It 
orbited giant asteroid Vesta for 14 months from 2011 to 2012, then continued 
on to Ceres, where it has been in orbit since March 2015.

The Dawn mission is managed by JPL for NASA's Science Mission Directorate 
in Washington. Dawn is a project of the directorate's Discovery Program, 
managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. 
UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., 
in Dulles, Virginia, designed and built the spacecraft. The German Aerospace 
Center, Max Planck Institute for Solar System Research, Italian Space 
Agency and Italian National Astrophysical Institute are international 
partners on the mission team. For a complete list of mission participants, 
visit:

https://dawn.jpl.nasa.gov/mission

More information about Dawn is available at the following sites:

https://www.nasa.gov/dawn

https://dawn.jpl.nasa.gov

News Media Contact
Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
(818) 354-6425
Elizabeth.Landau at jpl.nasa.gov

2017-275