An arcjet rocket or arcjet thruster is a form of

electrically powered spacecraft propulsion Spacecraft electric propulsion (or just electric propulsion) is a type of spacecraft propulsion technique that uses electrostatic or electromagnetic fields to accelerate mass to high speed and thus generating thrust to modify the velocity of a ...

, in which an

electrical discharge In electromagnetism, an electric discharge is the release and transmission of electricity in an applied electric field through a medium such as a gas (i.e., an outgoing flow of electric current through a non-metal medium).American Geophysical U ...

( arc) is created in a flow of propellant (typically

hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydraz ...

ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...

). This imparts additional energy to the propellant, so that one can extract more work out of each kilogram of propellant, at the expense of increased power consumption and (usually) higher cost. Also, the

thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that ...

levels available from typically used arcjet engines are very low compared with chemical engines. When the energy is available, arcjets are well suited to keeping stations in orbit and can replace

monopropellant rocket A monopropellant rocket (or "monochemical rocket") is a rocket that uses a single chemical as its propellant. Monopropellant rockets are commonly used as small attitude and trajectory control rockets in satellites, rocket upper stages, crewed spac ...

s. Aerojet MR-510 series arcjet engines are currently used on

Lockheed Martin A2100 The A2100 is a model of communications satellite spacecraft made by Lockheed Martin Space Systems. It is used as the foundation for telecommunications payloads in geosynchronous orbit, as well as GOES-R weather satellites and GPS Block IIIA satel ...

satellites using hydrazine as a propellant, providing over 585 s average

specific impulse Specific impulse (usually abbreviated ) is a measure of how efficiently a reaction mass engine, such as a rocket engine, rocket using propellant or a jet engine using fuel, generates thrust. In general, this is a ratio of the ''Impulse (physics), ...

at 2 kW. In

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

, researchers at the

University of Stuttgart The University of Stuttgart () is a research university located in Stuttgart, Germany. It was founded in 1829 and is organized into 10 faculties. It is one of the oldest technical universities in Germany with programs in civil, mechanical, ind ...

's Institute of Space Aviation Systems have been working with arcjets for years and have developed various

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

-powered arcjet engines capable of power outputs from 1 to 100 kW. The heated hydrogen reaches exit speeds of . An arcjet-propelled test satellite by the name of

Baden-Württemberg 1 Baden-Württemberg 1 (BW1) was a proposed lunar mission spacecraft. The mission was led by the University of Stuttgart. The basic design was for a cubical spacecraft 1 meter on a side, with a mass of about 200 kg (441 lb). It may us ...

(BW1) was scheduled to go to the Moon by 2010. No such launch has yet occurred. Baden-Württemberg 1 would have used

polytetrafluoroethylene Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene, and has numerous applications because it is chemically inert. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a corporate spin-of ...

(PTFE) propellant.Bietigheim-Bissingen, 11/20/2008

References

External links

Aerojet Rocketdyne - Arcjet thruster vendor
{{DEFAULTSORT:Arcjet Rocket Rocket propulsion

References

Further reading

External links