Thrusters

A thruster is a propulsive device which is utilized by watercraft and spacecraft for attitude control, station keeping, and long duration low thrust acceleration or in the reaction control system.

The growing demand for communication, navigation and research satellites during the next decade and beyond provides an opportunity for plasma thrusters to be employed for orbit correc­tions. One successful example of the application of an ion thruster sustained by solar energy was the Deep Space 1 launched October 24, 1998 and retired December 18^th, 2001 which was used for the investigation of comets. The useful lifetime of today's satellites could be enhanced by a factor of 5, if the spacecraft had sufficient fuel for required orbit corrections. If the mass equivalent of this fuel could be fed into a plasma thruster, more thrust could be produced by e.g. using an E x /J-plasma thruster which produces higher kinetic energies than the particles of chemical thrusters. Since additional equipment for the plasma thruster may burden the pay load, an economic gain of the equivalent of two satellite missions per rocket launched might be realistic. Depending on the annual demand for new satellites, an economic value in the billions of Euro per year by plasma technology could be obtained E x /J -thrusters have been under study since the 1960s.

Thrusters were essential to success in several missions. They were essential in the following cases:

NR-1 had to be held against a cross current and bottoming was not an option (because of bottom conditions).

• Thrusters were needed to maneuver NR-1 safely out of tight spaces, such as sinkholes.
• Thrusters were used to help keep NR-1 bottomed against wave action in shallow water.

Questionnaire:

• What is thruster?
• What are the uses of the thruster?
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