LISA Pathfinder is the revised name for SMART-2, a NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

/ESA space probe to be launched in June 2013. SMART stands for Small Missions for Advanced Research in Technology. The aim of the LISA Pathfinder is to test technologies needed for the Laser Interferometer Space Antenna

Laser Interferometer Space Antenna

The Laser Interferometer Space Antenna is a planned space mission to detect and accurately measure gravitational waves from astronomical sources. LISA was originally conceived as a joint effort between the United States space agency NASA and the European Space Agency...

, a joint NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

/ESA gravitational wave

Gravitational wave

In physics, gravitational waves are theoretical ripples in the curvature of spacetime which propagates as a wave, traveling outward from the source. Predicted to exist by Albert Einstein in 1916 on the basis of his theory of general relativity, gravitational waves theoretically transport energy as...

 detector. It will contain one arm of the LISA interferometer

Laser Interferometer Space Antenna

The Laser Interferometer Space Antenna is a planned space mission to detect and accurately measure gravitational waves from astronomical sources. LISA was originally conceived as a joint effort between the United States space agency NASA and the European Space Agency...

, shortened from 5 Gm (5 million km) to 35 cm. In particular, it will verify:

• Drag-free attitude control of a spacecraft with two proof masses,
• The feasibility of laser interferometry in the desired frequency band (which is not possible on the surface of Earth), and
• The reliability and longevity of the various components—capacitive sensors, microthrusters, lasers and optics.

Spacecraft design

LISA Pathfinder is being built by EADS Astrium Ltd.

EADS Astrium

Astrium Satellites is one of the three business units of Astrium, a subsidiary of EADS. It is a European space manufacturer involved in the manufacture of spacecraft used for science, Earth observation and telecommunication, as well as the equipment and subsystems used therein and related ground...

 of Stevenage, UK under contract to the European Space Agency. It will carry a European 'LISA Test Package' comprising inertial sensors, interferometer and associated instrumentation as well as two drag-free control systems: a European one using field emission electric propulsion

Field Emission Electric Propulsion

Field-emission electric propulsion is an advanced electrostatic propulsion concept, a form of ion thruster, that uses liquid metal as a propellant. A FEEP device consists of an emitter and an accelerator electrode...

 (FEEP) thrusters, and a US-built 'Disturbance Reduction System' using slightly different sensors and colloid thruster

Colloid thruster

]A colloid thruster is a type of thruster which uses electrostatic acceleration of charged liquid droplets for propulsion. It is closely related to electrospray ionization and other hydrodynamic spraying processes. In a colloid thruster charged liquid droplets are produced by an electrospray...

s that use ionised droplets of a colloid accelerated in an electric field

Electric field

In physics, an electric field surrounds electrically charged particles and time-varying magnetic fields. The electric field depicts the force exerted on other electrically charged objects by the electrically charged particle the field is surrounding...

.

Instrumentation

The LISA Test Package is being integrated by Astrium Germany, but the instruments and components are being supplied to Astrium by contributing institutions across Europe. The noise rejection technical requirements on the interferometer are very stringent, which means that the physical response of the interferometer to changing environmental conditions, such as temperature, must be minimised.

Orbit

The spacecraft will first be launched into an elliptical LEO

Low Earth orbit

A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...

 parking orbit. From there it will execute a short burn each time perigee

Perigee

Perigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...

 is passed, slowly raising the apogee closer to the intended halo orbit

Halo orbit

A halo orbit is a periodic, three-dimensional orbit near the , , or Lagrange points in the three-body problem of orbital mechanics. A spacecraft in a halo orbit does not technically orbit the Lagrange point itself , but travels in a closed, repeating path near the Lagrange point...

 around the Earth–Sun point. If this mission is successful, it is hoped that the LISA mission will be launched a few years later, current estimates are around 2018.

Spacecraft operations

Mission control for the LISA Pathfinder mission will be at ESOC

European Space Operations Centre

The European Space Operations Centre is responsible for controlling ESA satellites and space probes. The centre is located in Darmstadt, Germany. It is Mission Control for most of the space projects of the ESA. Since its creation in 1967, the centre has operated 60 European space missions...

 in Darmstadt, Germany with science and technology operations controlled from ESAC in Madrid, Spain

Madrid

Madrid is the capital and largest city of Spain. The population of the city is roughly 3.3 million and the entire population of the Madrid metropolitan area is calculated to be 6.271 million. It is the third largest city in the European Union, after London and Berlin, and its metropolitan...

.