NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
In-Flight Operation of the Dawn Ion Propulsion System Through Orbit Capture at VestaThe Dawn mission, part of NASA's Discovery Program, has as its goal the scientific exploration of the two most massive main-belt asteroids, Vesta and Ceres. The Dawn spacecraft was launched from Cape Canaveral Air Force Station on September 27, 2007 on a Delta -II 7925H-9.5 (Delta-II Heavy) rocket that placed the 1218 kg spacecraft into an Earth-escape trajectory. Onboard the spacecraft is an ion propulsion system (IPS) developed at the Jet Propulsion Laboratory which will provide most of the ?V needed for heliocentric transfer to Vesta, orbit capture at Vesta, transfer among Vesta science orbits, departure and escape from Vesta, heliocentric transfer to Ceres, orbit capture at Ceres, and transfer among Ceres science orbits. The first 80 days after launch were dedicated to the initial checkout of the spacecraft which was followed by about ten months of full-power thrusting leading to a Mars gravity assist in February 2009 that provided 1 km/s of heliocentric energy increase and is the only part of the mission following launch in which a needed velocity change is not accomplished by the IPS. Deterministic thrusting for heliocentric transfer to Vesta resumed in June 2009 and was concluded with orbit capture at Vesta in July 2011. IPS was operated for approximately 23,400 hours, consumed approximately 250 kg of xenon, and provided a delta-V of approximately 6.7 km/s to achieve orbit capture at Vesta. IPS performance characteristics are very close to the expected performance characteristics based on analysis performed pre-launch. The only significant problem to have occurred over the almost four years of IPS operations in flight was the temporary failure of a valve driver board in DCIU-1, resulting in a loss of thrust of approximately 29 hours. Thrusting operations resumed after switching to DCIU-2, and power cycling conducted after orbit capture indicates DCIU-1 is completely operational. After about three weeks of survey operations IPS will be used to maneuver the spacecraft as needed for science operations including orbit transfers. After approximately one year of science operations IPS will then be used for escape from Vesta and begin thrusting for cruise to Ceres with a planned arrival date at Ceres in February 2015. This paper provides an overview of Dawn's mission objectives and the results of Dawn IPS mission operations through orbit capture and the start of science operations at Vesta.
Document ID
20150008816
Acquisition Source
Jet Propulsion Laboratory
Document Type
Conference Paper
External Source(s)
Authors
Garner, Charles E.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Rayman, Marc D.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Brophy, John R.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Mikes, Steven C.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
May 26, 2015
Publication Date
July 31, 2011
Subject Category
Spacecraft Propulsion And Power
Meeting Information
Meeting: AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit
Location: San Diego, CA
Country: United States
Start Date: July 31, 2011
End Date: August 3, 2011
Sponsors: American Society for Engineering Education, American Inst. of Aeronautics and Astronautics, American Society of Mechanical Engineers, Society of Automotive Engineers, Inc.
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available