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 generate thrust to modify the velocity of a s ...
, in which an electrical discharge (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 toxic unless handled in solution as, for example, hydrazine ...
or
ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...
). 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 syst ...
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.
Chemical-reaction monopropellant rockets
For monopropellant rockets that depend on a chemical reaction, the power for the propulsive re ...
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 satell ...
satellites using hydrazine as a propellant, providing over 585s average specific impulse at 2
kW.
In
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
, researchers at the
University of Stuttgart
The University of Stuttgart (german: Universität Stuttgart) is a leading 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 wit ...
's Institute of Space Aviation Systems have been looking into these challenges for years and have developed various
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...
-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.[polytetrafluoroethylene
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemour ...]
PTFE propellant.
Bietigheim-Bissingen, 11/20/2008
References
Further reading
* ''Lichtbogenantriebe für Weltraumaufgaben'' (Arcjet propulsion systems for space applications), Prof. Monika Auweter-Kurtz, B.G. Teubner Stuttgart 199
Institute of Space Systems at the University of Stuttgart
External links
Aerojet Rocketdyne - Arcjet thruster vendor
{{DEFAULTSORT:Arcjet Rocket
Rocket propulsion