JPL
Careers
Education
Science & Technology
JPL Logo
JPL Logo
Solar System
.

Dawn Observing Ceres; 3rd Reaction Wheel Malfunctions

Apr 26, 2017
Artist's concept of NASA's Dawn spacecraft orbiting dwarf planet Ceres.› Full image and caption
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

NASA's Dawn spacecraft is preparing to observe Ceres on April 29 from an "opposition" position, directly between the dwarf planet's mysterious Occator Crater and the sun.

Mission Status Report

NASA's Dawn spacecraft is preparing to observe Ceres on April 29 from an "opposition" position, directly between the dwarf planet's mysterious Occator Crater and the sun. This unique geometry may yield new insights about the bright material in the center of the crater.

While preparing for this observation, one of Dawn's two remaining reaction wheels stopped functioning on April 23. By electrically changing the speed at which these gyroscope-like devices spin, Dawn controls its orientation in the zero-gravity, frictionless conditions of space.

The team discovered the situation during a scheduled communications session on April 24, diagnosed the problem, and returned the spacecraft to its standard flight configuration, still with hydrazine control, on April 25. The failure occurred after Dawn completed its five-hour segment of ion thrusting on April 22 to adjust its orbit, but before the shorter maneuver scheduled for April 23-24. The orbit will still allow Dawn to perform its opposition measurements. The reaction wheel's malfunctioning will not significantly impact the rest of the extended mission at Ceres.

Dawn completed its prime mission in June 2016, and is now in an extended mission. It has been studying Ceres for more than two years, and before that, the spacecraft orbited giant asteroid Vesta, sending back valuable data and images. Dawn launched in 2007.

The Dawn operations team has been well prepared to deal with the loss of the reaction wheel. The spacecraft is outfitted with four reaction wheels. It experienced failures of one of the wheels in 2010, a year before it entered orbit around Vesta, and another in 2012, as it was completing its exploration of that fascinating world. (See issues with these devices). When a third reaction wheel stopped working this week, the spacecraft correctly responded by entering one of its safe modes and assigning control of its orientation to its hydrazine thrusters.

Today, Dawn's elliptical orbit will bring it from an altitude of 17,300 miles (27,900 kilometers) to 15,800 miles (25,400 kilometers) above Ceres.

The Dawn mission is managed by NASA's Jet Propulsion Laboratory in Pasadena, California, 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

Headquarters, Washington

202-358-0845

elandau@nasa.gov

2017-125

Related News

Mars .

NASA’s Perseverance Mars Rover Extracts First Oxygen From Red Planet

Mars .

NASA’s Ingenuity Mars Helicopter Succeeds in Historic First Flight

Mars .

NASA to Attempt First Controlled Flight on Mars As Soon As Monday

Mars .

NASA’s Mars Helicopter to Make First Flight Attempt

Mars .

NASA’s Odyssey Orbiter Marks 20 Historic Years of Mapping Mars

Solar System .

Probing for Life in the Icy Crusts of Ocean Worlds

Mars .

NASA’s First Weather Report From Jezero Crater on Mars

Mars .

NASA Invites Public to Take Flight With Ingenuity Mars Helicopter

Mars .

NASA’s Mars Helicopter Survives First Cold Martian Night on Its Own

Mars .

Sensors Collect Crucial Data on Mars Landings With Arrival of Perseverance

Explore More

Image .

Goldstone Radar Observations of Asteroid 2001 FO32

Video .

What's Up - April 2021

Image .

Europa Clipper Spacecraft (Illustration)

Image .

Europa Imaging System Wide Angle Camera

Image .

Faraday Cups Up Close: NASA's Europa Clipper

Image .

Europa Clipper's Thermal Tubing

Image .

Europa Imaging System Narrow Angle Camera

Image .

Europa Clipper REASON Testing on the Mesa

Image .

Europa Clipper's Europa Imaging System in the Works

Image .

Preparing NASA's Europa Clipper's Plasma Instrument

About JPL
Who We Are
Executive Council
Directors of JPL
JPL History
Documentary Series
Virtual Tour
Annual Reports
Missions
All
Current
Past
Future
News
All
Earth
Mars
Solar System
Universe
Technology
Galleries
Images
Videos
Audio
Podcasts
Infographics
Visions of the Future
Slice of History
Engage
JPL and the Community
Lecture Series
Public Tours
Events
Team Competitions
JPL Speakers Bureau
Topics
Solar System
Mars
Earth
Climate Change
Stars and Galaxies
Exoplanets
Technology
JPL Life
For Media
Contacts and Information
Press Kits
More
Asteroid Watch
Robotics at JPL
Subscribe to Newsletter
Universe Newsletter
Social Media
RSS
Get the Latest from JPL
Follow Us

JPL is a federally funded research and development center managed for NASA by Caltech.

More from JPL
Careers Education Science & Technology Acquisitions JPL Store
Careers
Education
Science & Technology
Acquisitions
JPL Store
Related NASA Sites
Basics of Spaceflight
Climate Kids
Earth / Global Climate Change
Exoplanet Exploration
Mars Exploration
Solar System Exploration
Space Place
NASA's Eyes Visualization Project
Voyager Interstellar Mission
NASA
Caltech
Privacy
Image Policy
FAQ
Feedback
Site Manager: Veronica McGregor
Site Editors: Tony Greicius, Randal Jackson, Naomi Hartono