An ion engine test

This article focuses on electrostatic ion thrusters - for a more general description, refer to electric propulsion. Ion engine in operation (from Great Images in NASA) File links The following pages link to this file: Spacecraft propulsion Ion thruster User:Patrick/w Categories: NASA images ... Ion engine in operation (from Great Images in NASA) File links The following pages link to this file: Spacecraft propulsion Ion thruster User:Patrick/w Categories: NASA images ... This article or section does not cite its references or sources. ...

An ion thruster (more specifically an electrostatic ion thruster) is one of several types of spacecraft propulsion, specifically electric propulsion. It uses beams of ions — electrically charged atoms or molecules — for propulsion. The precise method for accelerating the ions may vary, but all designs take advantage of the charge-to-mass ratio of ions to accelerate them to very high velocities using a high electric field. Ion thrusters are therefore able to achieve high specific impulse, reducing the amount of reaction mass required, but increasing the amount of specific power required compared to chemical rockets. Ion thrusters can generally deliver one order of magnitude greater propellant efficiency than traditional liquid fuel rocket engines, but are constrained to very low accelerations by the power/mass ratios of available power sources. A remote camera captures a close-up view of a Space Shuttle Main Engine during a test firing at the John C. Stennis Space Center in Hancock County, Mississippi Spacecraft propulsion is any method used to change the velocity of spacecraft and artificial satellites. ... This article or section does not cite its references or sources. ... This article is about the electrically charged particle. ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. ... This article or section is in need of attention from an expert on the subject. ... Specific impulse (usually abbreviated Isp) is a way to describe the efficiency of rocket and jet engines. ... Working mass is a mass against which a system operates in order to produce acceleration. ... In physics, power (symbol: P) is the rate at which work is performed or energy is transferred. ... A remote camera captures a close_up view of a Space Shuttle Main Engine during a test firing at the John C. Stennis Space Center in Hancock County, Mississippi Spacecraft propulsion is used to change the velocity of spacecraft and artificial satellites, or in short, to provide delta_v. ... An order of magnitude is the class of scale or magnitude of any amount, where each class contains values of a fixed ratio to the class preceding it. ... A propellant is a material that is used to move an object by applying a motive force. ... Liquid fuels are those combustible or energy-generating molecules which can be harnessed to create mechanical energy, which in turn usually produces kinetic energy, and which also must take the shape of their container. ...

The principles of Ion thrusters go back to the concepts developed by the German/Austrian physicist Hermann Oberth which were published in his famous 1929 work "Die Rakete zu den Planetenräumen" (The rocket to planetary space). Not to be confused with physician, a person who practices medicine. ... Oberth (in front) with fellow ABMA employees. ...

The first ion thrusters, known as Kaufman-type ion thrusters, were developed by Harold R. Kaufman, working for NASA in the 1960s, and were based on the Duoplasmatron. Harold R. Kaufman is an American physicist, noted for his development of ion beam thrusters for NASA during the 1950s and 60s. ... This article is about the American space agency. ... Duoplasmatron, an invention of Manfred von Ardenne, is a type of ion beam source. ...

Ion engines have enjoyed possibly the most "Hollywood press" of electric propulsion systems, most notably appearing as the propulsion system of the TIE fighters in the Star Wars universe, among other works. However, the maneuvering capabilities displayed in those fictional works are well beyond current ion engine technology in the real world, as these engines typically only produce low accelerations. Ion thrusters are operated over several hours to months to provide the desired change in velocity, delta-V, to compensate for this. ... TIE Fighter, see X-wing computer game series. ... Star Wars is an epic space opera saga and a fictional universe initially developed by George Lucas during the 1970s and expanded since that time. ... General In general physics delta-v is simply the change in velocity. ...

Types of ion thruster

The term ion thruster usually refers to Electrostatic ion thrusters, the earliest form of spacecraft electric propulsion. It can though be used to describe other types of spacecraft electric propulsion, that also use ions to accelerated by a high voltage grid to provide the change in momentum. Some of the types of ion thruster are: The electrostatic ion thruster is a kind of design for ion thrusters (a kind of highly-efficient low-thrust spacecraft propulsion running on electrical power). ...

• Electrostatic ion thrusters
• Hall effect thrusters
• Colloid thrusters. Generally though colloid thrusters use large charged droplets, rather than ions. They can produce ions though under certain conditions.
• Field Emission Electric Propulsion (FEEP)
• DS4G also known as the Dual-Stage 4-Grid^{[1] [2]}

Other forms of high-efficiency electric thruster have also been proposed; see spacecraft propulsion. The electrostatic ion thruster is a kind of design for ion thrusters (a kind of highly-efficient low-thrust spacecraft propulsion running on electrical power). ... 2 kW Laboratory Hall Thruster in operation at the Princeton Plasma Physics Laboratory A Hall effect thruster is a type of ion thruster in which the propellant is accelerated by an electric field in a plasma discharge with a radial magnetic field. ... 20 μN colloid thruster system[1] A colloid thruster is a type of ion thruster which uses electrostatic acceleration of charged liquid droplets for propulsion. ... Field Emission Electric Propulsion (FEEP) is an advanced electrostatic propulsion concept, a form of ion thruster, that uses liquid metal (usually either cesium or indium) as a propellant. ... A remote camera captures a close-up view of a Space Shuttle Main Engine during a test firing at the John C. Stennis Space Center in Hancock County, Mississippi Spacecraft propulsion is any method used to change the velocity of spacecraft and artificial satellites. ...

General design

A diagram of how an electrostatic ion engine works

In an electrostatic ion thruster, atoms of argon, mercury or xenon are ionized by exposure to electrons provided by a cathode filament. The ions are accelerated by passing them through highly charged grids. Electrons are also fired into the ion beam downstream of the grids as the positively charged ions leave the thruster. This keeps the spacecraft and the thruster beams neutral electrically. The acceleration uses up very little reaction mass (i.e., the specific impulse, or I_sp, is very high). In the 1970s and 1980s, research of ion propulsion first began with cesium, but this was found to erode the grid. After that, the mid-noble gases were mainly used as a propulsion source. Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ... The electrostatic ion thruster is a kind of design for ion thrusters (a kind of highly-efficient low-thrust spacecraft propulsion running on electrical power). ... General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18, 3, p Appearance colorless Standard atomic weight 39. ... General Name, Symbol, Number mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12, 6, d Appearance silvery Standard atomic weight 200. ... General Name, Symbol, Number xenon, Xe, 54 Chemical series noble gases Group, Period, Block 18, 5, p Appearance colorless Standard atomic weight 131. ... Ionization is the physical process of converting an atom or molecule into an ion by changing the difference between the number of protons and electrons. ... Diagram of a copper cathode in a Daniells cell. ... Filaments surrounding a solar flare, caused by the interaction of the plasma in the Suns atmopshere with its magnetic field. ... Specific impulse (usually abbreviated Isp) is a way to describe the efficiency of rocket and jet engines. ... General Name, Symbol, Number Caesium, Cs, 55 Series Alkali metals Group, Period, Block 1(IA), 6, s Density, Hardness 1879 kg/m3, 0. ... The noble gases are a chemical series. ...

Energy usage

Energetic efficiency as a function of vehicle speed compared to exhaust speed; for many missions Ion thrusters travel at about 1/10 of the exhaust jet speed

A major consideration is the amount of power required to run the thruster, partly to ionize the materials, but mostly to accelerate the ions to the extremely high speeds required to have any useful effect. Exhaust speeds of 30 km/s are not uncommon, which is far faster than the 3–4.5 km/s for chemical rockets, or the speed of the vehicle. This makes for notably low propellant usage. Image File history File links PropulsiveEfficiency. ... Image File history File links PropulsiveEfficiency. ...

The exhaust velocity attained by ions when they are accelerated inside an electric field can be calculated from the kinetic and electric potential energy:

E_p = QV

Where v_i is the velocity of the accelerated ion, Q is the charge of the ion, m_i is the mass of the ion, and V is the potential difference across with the electric field.

Rearranging gives a term for the exhaust velocity;

Thrust

Assuming that the amount of ions leaving the thruster is constant, then the thrust is given by;

where:

T = thrust (force) generated,

mass flow rate.

In practice, with currently practical energy sources of perhaps a few tens of kilowatts, and given a typical I_sp of 3000 seconds (30 kN·s/kg), ion thrusters give only extremely modest forces (often tenths or hundredths of a newton). Large ion propulsion engines require large electric power sources. Ion engines typically provide space craft acceleration rates of from 10⁻⁵ g to 10⁻³ g (0.000098 m/s² to 0.0098 m/s²). For other uses, see Newton (disambiguation). ... The term g force or gee force refers to the symbol g, the force of acceleration due to gravity at the earths surface. ...

Lifespan

Given the low thrust, the life of the thruster becomes important. Ion thrusters have to be kept running a large part of the time to allow the milligee acceleration to gain a useful velocity.

In the simplest ion thruster design, an electrostatic ion thruster, the ions often hit the grids, which leads to erosion of the grids and their eventual failure. Smaller grids lower the chance of these accidental collisions, but decrease the amount of charge they can handle, and thus lower the thrust. The electrostatic ion thruster is a kind of design for ion thrusters (a kind of highly-efficient low-thrust spacecraft propulsion running on electrical power). ...

Missions

Of all the electric thrusters, ion thrusters have been the most seriously considered commercially and academically in the quest for interplanetary missions and orbit raising maneuvers. Ion thrusters are seen as the best solution for these missions as they require very high change in velocity overall that can be built up over long periods of time. An Interplanetary Mission is a voyage or trip through space involving more than one planet. ...

SERT

Several spacecraft have operated with this technology. The first was SERT ^[3] in the 1970's. The Special Emergency Response Team (SERT) was the RCMP counter-terrorism unit which existed until 1993. ...

Smart 1

The Hall effect thruster is a type of ion thruster that has been used for decades for station keeping by the Soviet Union and is now also applied in the West: the European Space Agency's satellite Smart 1 used it (Snecma PPS-1350-G). This satellite completed its mission on September 3, 2006, in a controlled collision on the Moon's surface, after a trajectory deviation to be able to see the 3 meter crater the impact created on the visible side of the moon. 2 kW Laboratory Hall Thruster in operation at the Princeton Plasma Physics Laboratory A Hall effect thruster is a type of ion thruster in which the propellant is accelerated by an electric field in a plasma discharge with a radial magnetic field. ... In astrodynamics orbital stationkeeping is a term used to describe a particular set of orbital maneuvers used to keep a spacecraft in assigned orbit, either low earth orbit (LEO), or geostationary orbit (GEO). ... “ESA” redirects here. ... SMART-1 was a Swedish-designed European Space Agency satellite that orbited around the Moon. ... Two Snecma PPS 1350 at the Paris Air Show 2007 PPS-1350 is a Hall effect thruster, a kind of ion propulsion system for spacecraft. ... This article is about Earths moon. ...

Artemis

On 12 July 2001, the European Space Agency failed to launch their Artemis telecommunication satellite, and left it in a decaying orbit. The satellite's chemical propellant supply was sufficient to transfer it to a semi-stable orbit, and over the next 18 months the experimental onboard ion propulsion system (intended for secondary stationkeeping and maneuvering) was utilized to transfer it to a geostationary orbit. ^[4] “ESA” redirects here. ...

Deep Space 1

NASA has developed an ion thruster called NSTAR for use in their interplanetary missions. This thruster was tested in the highly successful space probe Deep Space 1. Hughes has developed the XIPS (Xenon Ion Propulsion System) for performing stationkeeping on geosynchronous satellites. These are electrostatic ion thrusters and work by a different principle than Hall effect thrusters. This article is about the American space agency. ... NSTAR is a private utility company that provides retail electricity and natural gas to customers in eastern and central Massachusetts. ... The spacecraft Deep Space 1 was launched October 24, 1998 on top of a Delta II rocket. ... Hughes logo adopted after his death Hughes developed the AIM-120 AMRAAM, one of the worlds most advanced air-to-air missiles Hughes Aircraft Company was a major defense/aerospace company founded by Howard Hughes. ... A geosynchronous satellite is a satellite whose orbital track on the Earth repeats regularly over points on the Earth over time. ... The electrostatic ion thruster is a kind of design for ion thrusters (a kind of highly-efficient low-thrust spacecraft propulsion running on electrical power). ...

Dawn

Dawn was launched on 27 September 2007 to explore the dwarf planet Ceres and the asteroid Vesta. To cruise from Earth to its targets it will use 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 0-60 mph in 4 days.^[5] The Dawn Mission is a NASA mission that will send the Dawn spacecraft, a robotic space probe, to the asteroid belt. ... is the 270th day of the year (271st in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... Spectral type: G[8] Absolute magnitude: 3. ... 4 Vesta (ves-ta) is the second most massive asteroid in the asteroid belt, with a mean diameter of about 530 km and an estimated mass 12% the mass of the entire asteroid belt. ... This article is about Earth as a planet. ... The spacecraft Deep Space 1 was launched October 24, 1998 on top of a Delta II rocket. ...

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, is powered by four xenon Ion Engines. It is using xenon ions generated by microwave ECR, and a Carbon / Carbon-composite material for acceleration grid which is resistant to erosion.^[6] For other uses, see Hayabusa (disambiguation). ... Image:25143 Itokawa 051101-2 ISAS-JAXA.jpg Hayabusa image of 25143 Itokawa. ...

LISA Pathfinder

LISA Pathfinder is an ESA spacecraft to be launched in 2009. It will not use ion thrusters as its primary propulsion system, but will use both colloid thrusters and FEEP for very precise attitude control - the low thrusts of these propulsion devices make it possible to move the spacecraft incremental distances very accurately. It is a test for the possible LISA mission. LISA Pathfinder is the revised name for SMART-2, an ESA space probe to be launched in 2008. ... This article is about the European Space Agency. ... 20 μN colloid thruster system[1] A colloid thruster is a type of ion thruster which uses electrostatic acceleration of charged liquid droplets for propulsion. ...

Development

In 2003 NASA ground-tested a new version of their ion thruster called High Power Electric Propulsion, or HiPEP. The HiPEP thruster differs from earlier ion thrusters because the xenon ions are produced using a combination of microwave energy and magnetic fields. The ionization is achieved through a process called electron cyclotron resonance (ECR). In ECR, a uniform magnetic field is applied to a chamber holding xenon gas. The small number of free electrons present in the neutral gas orbit around the magnetic field lines at a fixed frequency called the cyclotron frequency. Microwave radiation is applied that is carefully tuned to this frequency, supplying energy to the electrons, which then ionize more xenon atoms through collisions. This process is a highly efficient means of creating a plasma in low density gases. Previously the electrons required were provided by a hollow cathode. HiPEP Beam Extraction Test In 2003 NASA ground-tested a new version of their ion thruster called High Power Electric Propulsion, or HiPEP. Theory The HiPEP thruster differs from earlier ion thrusters because the xenon ions are produced using a combination of microwave and magnetic fields. ... General Name, Symbol, Number xenon, Xe, 54 Chemical series noble gases Group, Period, Block 18, 5, p Appearance colorless Standard atomic weight 131. ... This article is about the type of Electromagnetic radiation. ... Magnetic field lines shown by iron filings In physics, the space surrounding moving electric charges, changing electric fields and magnetic dipoles contains a magnetic field. ... Electron cyclotron resonance is a phenomenon observed both in plasma physics and condensed matter physics. ... Magnetic field lines shown by iron filings In physics, the space surrounding moving electric charges, changing electric fields and magnetic dipoles contains a magnetic field. ... For other uses, see Electron (disambiguation). ... A pair of Dee electrodes with loops of coolant pipes on their surface at the Lawrence Hall of Science. ... This article is about the type of Electromagnetic radiation. ... For other uses, see Plasma. ... For other uses, see Gas (disambiguation). ...

See also

energy Portal

• Electric propulsion
• Spacecraft propulsion
• Nuclear electric rocket
• Hall effect thruster
• Magnetoplasmadynamic thruster
• Electrodeless plasma thruster
• Field Emission Electric Propulsion
• Pulsed inductive thruster
• VASIMR
• EmDrive

Image File history File links Portal. ... This article or section does not cite its references or sources. ... A remote camera captures a close-up view of a Space Shuttle Main Engine during a test firing at the John C. Stennis Space Center in Hancock County, Mississippi Spacecraft propulsion is any method used to change the velocity of spacecraft and artificial satellites. ... In a nuclear electric rocket, nuclear thermal energy is changed into electrical energy that is used to power one of the electrical propulsion technologies. ... 2 kW Laboratory Hall Thruster in operation at the Princeton Plasma Physics Laboratory A Hall effect thruster is a type of ion thruster in which the propellant is accelerated by an electric field in a plasma discharge with a radial magnetic field. ... An MPD thruster during test firing The Magnetoplasmadynamic (MPD) thruster (MPDT) is a form of electric propulsion (a subdivision of spacecraft propulsion) which uses the Lorentz force (a force resulting from the interaction between a magnetic field and an electric current) to generate thrust. ... The Electrodeless Plasma Thruster is a spacecraft propulsion engine. ... Field Emission Electric Propulsion (FEEP) is an advanced electrostatic propulsion concept, a form of ion thruster, that uses liquid metal (usually either cesium or indium) as a propellant. ... Pulsed inductive thrusters or PITs as they are commonly abbreviated are a form of spacecraft propulsion that uses perpendicular electric and magnetic fields to accelerate a propellant. ... VASIMR test bed The Variable specific impulse magnetoplasma rocket (VASIMR) is a hypothetical form of spacecraft propulsion that uses radio waves and magnetic fields to accelerate a propellant. ... New Scientist. ...

References