Can someone shed more light on this??
What is an ion thruster and what are its advantages??
Ion thruster - Wikipedia, the free encyclopedia
Energy efficiency
The actual overall system energy efficiency in use is determined by the
propulsive efficiency, which depends on vehicle speed and exhaust speed. Some thrusters can vary exhaust speed in operation, but all can be designed with different exhaust speeds. At the lower end of Isps the overall efficiency drops, because the ionization takes up a larger percentage energy, and at the high end propulsive efficiency is reduced.
Optimal efficiencies and exhaust velocities can thus be calculated for any given mission to give minimum overall cost.
Applications
Ion thrusters have many applications for in-space propulsion. The best applications of the thrusters make use of the long lifetime when significant
thrust is not needed. Examples of this include orbit transfers,
attitude adjustments,
drag compensation for
low earth orbits, transporting cargo such as chemical fuels between
propellant depots and ultra fine adjustments for more scientific missions. Ion thrusters can also be used for interplanetary and deep space missions where time is not crucial. Continuous thrust over a very long time can build up a larger velocity than traditional chemical rockets.
Operational missions
Ion thrusters are routinely used for station-keeping on commercial and military communication satellites in geosynchronous orbit, including satellites manufactured by Boeing and by Hughes Aerospace. The pioneers in this field were the Soviet Union, who used SPT thrusters on a variety of satellites starting in the early 1970s.
Two geostationary satellites (ESA's
Artemis in 2001-2003
[33] and the US military's
AEHF-1 in 2010-2012
[34]) have used the ion thruster for orbit raising after the failure of the chemical-propellant engine. Boeing
[35] have been using ion thrusters for station-keeping since 1997, and plan in 2013-2014 to offer a variant on their 702 platform, which will have no chemical engine and use ion thrusters for orbit raising; this enables a significantly lower launch mass for a given satellite capability.
AEHF-2 used a chemical engine to raise perigee to 10150 miles and is then proceeding to geosynchronous orbit using electric propulsion.
[36]
In Earth orbit
GOCE
ESA's
Gravity Field and Steady-State Ocean Circulation Explorer was launched on March 16, 2009. It used ion propulsion throughout its twenty month mission to combat the air-drag it experienced in its low orbit before intentionally deorbiting on November 11, 2013.
In deep space
Deep Space 1
NASA developed the
NSTAR ion engine for use in their interplanetary science missions beginning in the late-1990s. This xenon-propelled ion thruster was first space-tested in the highly successful space probe
Deep Space 1, launched in 1998. This was the first use of electric propulsion as the interplanetary propulsion system on a science mission.
[29] Based on the NASA design criteria,
Hughes Research Labs, developed the XIPS (Xenon Ion Propulsion System) for performing
station keeping on
geosynchronous satellites.[
citation needed].
Hughes (EDD) manufactured the NSTAR thruster used on the spacecraft.
Hayabusa
The Japanese space agency's
Hayabusa, which was launched in 2003 and successfully rendezvoused with the asteroid
25143 Itokawa and remained in close proximity for many months to collect samples and information, was powered by four xenon ion engines. It used xenon ions generated by microwave
electron cyclotron resonance, and a carbon / carbon-composite material (which is resistant to erosion) for its acceleration grid.
[37] Although the ion engines on Hayabusa had some technical difficulties, in-flight reconfiguration allowed one of the four engines to be repaired, and allowed the mission to successfully return to Earth.
[38]
Smart 1
The
European Space Agency's satellite
SMART-1, launched in 2003, used a Snecma
PPS-1350-G Hall thruster to get from
GTO to lunar orbit. This satellite completed its mission on 3 September 2006, in a
controlled collision on the
Moon's surface, after a trajectory deviation so scientist could see the 3 meter crater the impact created on the visible side of the moon.
Dawn
Dawn was launched on 27 September 2007 to explore the asteroid
Vesta and the dwarf planet
Ceres. To cruise from
Earth to its targets it uses three
Deep Space 1 heritage xenon ion thrusters (firing only one at a time) to take it in a long outward spiral. An extended mission in which Dawn explores other asteroids after Ceres is also possible. Dawn's ion drive is capable of accelerating from 0 to 60 mph (97 km/h) in 4 days, firing continuously.
[39]
