Orbital Sciences Corporation

Dawn

Orbital is partnered with Principal Investigator Dr. Christopher Russell of UCLA and the Jet Propulsion Laboratory (JPL) for a never-before-attempted interplanetary mission funded by NASA's Discovery Program. The mission, Orbital's first planetary space science program, will culminate in the rendezvous, orbit and study of the two largest known asteroids in our solar system, Vesta and Ceres.

The primary scientific mission of the Dawn program is to advance our understanding of how the solar system was formed by studying the two asteroids located in the "main belt" between Mars and Jupiter. Earth-based studies indicate that the two protoplanets have very different compositions and have remained intact since their formation more than 4.6 billion years ago. The Dawn spacecraft will rendezvous with and orbit Vesta for eight months and conduct remote sensing observations using a suite of instruments. It will then leave Vesta and travel to Ceres and make the same types of measurements.

The Dawn spacecraft is NASA's first purely scientific mission powered by ion propulsion, the world's most advanced and efficient space propulsion technology. Ion propulsion is providing the velocity needed to reach Vesta and will also be used during asteroid proximity operations to raise and lower the spacecraft's orbit.

Performance:
Orbit (at target asteroids): As high as 4,500 km and as low as 25 km
Propulsion: Solar-electric (ion)
Power: 10kW at Earth, 1.4kw at Ceres
Mass: 1,237 kg (2,727 lbs.) at launch
Mission duration: 10 years


Status:
Successfully launched on September 27, 2007. Dawn continues to make progress on its journey deeper into space. Click here to find out where Dawn is now.

Customer:
Jet Propulsion Laboratory

Mission:
NASA Discovery program

Quick Facts
Vesta, the brightest asteroid, is named for the ancient Roman goddess of the hearth and is the only asteroid visible with the naked eye

Ceres, the largest asteroid and the first to be discovered, revolves around the Sun once every 4.6 terrestrial years and has a diameter estimated at about 960 km (575 miles)

The ion propulsion system to be employed by Dawn and pioneered on NASA's Deep Space 1 mission represents the culmination of over 50 years of development of electric engine systems in space begun by Dr. Wernher von Braun

Check Out
JPL Dawn web site

NASA Discovery Program website

More information on ion propulsion

Information on asteroids

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