Dawn Spacecraft

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Dawn Mission is a NASA robotic mission to explore asteroid Vesta and dwarf planet Ceres in the Asteroid Belt. Dawn spacecraft is NASA’s first purely scientific mission to be powered by ion propulsion and is Orbital’s first planetary mission. It was launched on 27 September, 2007 from Cape Canaveral Air Force Station Launch Complex 17 on a Delta II rocket.

Dawn Spacecraft - Dawn Mission Picture

Dawn is the first spacecraft to orbit two planetary bodies on a single voyage.


Mission Overview

Dawn is a planetary space science mission funded by NASA’s Discovery Program. Orbital is partnered with Principal Investigator Chris Russell of UCLA and the Jet Propulsion Laboratory (JPL).

Dawn’s main scientific aim is to advance our understanding of the origin and evolution of the solar system by studying two of the largest asteroids, Vesta and Ceres which appear to have remained intact since their formation 4.6 billion years ago. Earth-based studies indicate that these two protoplanets have very different and complementary compositions, which may provide clues to the conditions and processes of planetary formation.

Dawn Spacecraft used solar electric ion propulsion to first rendezvous and orbit Vesta and then travelled to Vesta. The spacecraft conducted remote sensing observations using its suite of science instruments .


Dawn Mission Timeline

* Launch: 27 September, 2007 (previous launch date was 30 June) from Cape Canaveral Air Force Station Launch Complex 17.
* 10.09.07 NASA’s Dawn spacecraft successfully completed the first test of its ion propulsion system in early October 2007.
* Mars gravity assist: March 2009
* Vesta: entered orbit on 16 July 2011
* Vesta: departure April 2012
* Ceres: entered orbit 6 March 2015
* End of primary mission July 2015
* Mission still active in July 2016


Spacecraft Specs:

Mass: 1,210 kg (2,668 lb.) at launch, 740 kg (1,631 lb.) dry
Communications: Deep Space Network – compatible with science downlink rates of 41-128 kbps
Dimensions: 20 m (65 ft) tip-to-tip, spacecraft body is 2 m (6 ft) high from separation plane to instrument deck.
Propulsion: Solar-electric propulsion using three gimballed NSTAR ion engines and monopropellant reaction control system.
Power: Gallium Arsenide triple junction solar arrays, 10 kW at Earth and 1.4 kW at Ceres
Orbit Altitude: At target asteroids: As high as 4,500 km and as low as 25 km
Reliability: Redundant and cross-strapped spacecraft bus electronics
Mission Life: 10 years


Instruments

Framing Camera (MPS/DLR) Visible
Gamma Ray and Neutron Detector (LANL)
Infrared Mapping Spectrometer (ASI/INAF)


About Dawn’s Ion Propulsion

Dawn spacecraft is NASA’s first purely scientific mission powered by solar electric ion propulsion. Ion propulsion provided the additional velocity needed to reach Vesta once the spacecraft separated from the Delta II Rockt. Ion propulsion was also used during asteroid proximity operations to raise and lower the orbit altitude. Dawn’s ion propulsion system is based on the technology successfully demonstrated by Deep Space 1.


Key Mission Partners

– Principal Investigator: Dr. Christopher Russell, UCLA
– Jet Propulsion Laboratory (JPL), Pasadena, CA (Project management, system engineering, ion propulsion subsystem, science operations and spacecraft flight operations)
– Kennedy Space Center, Cape Canaveral, Florida (Launch services via NASA Launch Services Contract).
– Orbital Sciences Corporation, Dulles, VA.
– Italian space agency/National Institute for Astrophysics, Rome, Italy
– Max Planck Institute for Solar System Research/German Space Agency


Did you know?

* Dawn carried a silicon chip containing the names of asteroid, space and other enthusiasts from around the world. People submitted their names for this historic one-way mission by visiting JPL’s Dawn Web site in 2006.

* In the mid 1980s a Multiple Asteroid and Comet Fly-By French Soviet Vesta Mission was proposed for 1991. Not approved.


Related Space Books

Asteroids and Dwarf Planets and How to Observe Them (Astronomers’ Observing Guides)
by Roger Dymock
From Amazon.comAmazon.co.ukAmazon.caeCampus.com

Impact!: The Threat of Comets and Asteroids
by Gerrit L. Verschuur
From Amazon.comAmazon.co.ukAmazon.ca


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