Photo: NASA
In September 2007, NASA’s Dawn spacecraft departed Earth heading for the asteroid belt, with the mission to study two protoplanets located there, Vesta and Ceres.
The probe is currently in its final stages of the mission, provided it doesn’t prove as resilient as the agency's Mars rovers, which exceeded their life expectancy by far. Dawn is to spend the next few months gathering science data and transmitting it to Earth from the orbit of Ceres.
This week, NASA fired the craft’s engines for the last time, saying that it does not expect to fire them up again.
Dawn is powered by what NASA calls a hyper-efficient ion propulsion system. This system allowed the probe to go into orbit around two different solar system bodies, a feat never achieved before.
The engine is comprised of three 30-centimeter-diameter (12- inch) ion thrust units that can move in two axes to allow for migration of the spacecraft's center of mass during the mission. Two of the thrusters are used every time they are needed, while the third acts as a spare.
The engines are powered with xenon fuel. An electrical charge is used to accelerate xenon ions to a speed 7-10 times that of chemical engines. About 10 ounces of xenon are used over 24 hours at maximum thrust.
During its 11 year mission, Dawn used its engines for a total of 5.87 years and reached a total effective velocity of 25,700 mph (41,360 km/h).
"Dawn's remarkable ion engines have taken us on an exciting extraterrestrial expedition that would have been impossible without them," said in a statement Marc Rayman of NASA's Jet Propulsion Laboratory.
"The engines are healthy and ready in case we ever need them again, but they have taken Dawn exactly where we want it to be. We will remember the engines and their cool blue glow with fondness and gratitude."
This week, NASA fired the craft’s engines for the last time, saying that it does not expect to fire them up again.
Dawn is powered by what NASA calls a hyper-efficient ion propulsion system. This system allowed the probe to go into orbit around two different solar system bodies, a feat never achieved before.
The engine is comprised of three 30-centimeter-diameter (12- inch) ion thrust units that can move in two axes to allow for migration of the spacecraft's center of mass during the mission. Two of the thrusters are used every time they are needed, while the third acts as a spare.
The engines are powered with xenon fuel. An electrical charge is used to accelerate xenon ions to a speed 7-10 times that of chemical engines. About 10 ounces of xenon are used over 24 hours at maximum thrust.
During its 11 year mission, Dawn used its engines for a total of 5.87 years and reached a total effective velocity of 25,700 mph (41,360 km/h).
"Dawn's remarkable ion engines have taken us on an exciting extraterrestrial expedition that would have been impossible without them," said in a statement Marc Rayman of NASA's Jet Propulsion Laboratory.
"The engines are healthy and ready in case we ever need them again, but they have taken Dawn exactly where we want it to be. We will remember the engines and their cool blue glow with fondness and gratitude."
Google News