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The LISA is the Laser Interferometer Space Antenna experiment. It was planned to be launched in 2015 or later, but in February 2006, the orientation of the NASA budget toward the exploration initiative caused the development phase of the mission to be infinitively deferred together with the other missions in the Beyond Einstein program. 2015 (MMXV) will be a common year starting on Thursday of the Gregorian calendar. ...
The NASA Beyond Einstein program is a program designed to explore the limits of Einsteins theory of General Relativity. ...
A selection of one mission in this program is expected to take place in 2008. 2008 (MMVIII) will be a leap year starting on Tuesday of the Gregorian calendar. ...
LISA is intended to measure gravitational waves by using laser interferometry over astronomical distances. It will use three spacecraft arranged in an equilateral triangle to form the arms of a giant Michelson interferometer with arms about 5 Gm (5 million kilometers) long. A Michelson interferometer consists of an L-shape with two long arms, each terminated with a mirror, and a corner station containing a light source, beam splitter, and combiner. When a gravitational wave disturbs the space-time field between two of the spacecraft, small differences in the relative lengths of the arms are measurable. In physics, gravitational radiation is energy that is transmitted through waves in the gravitational field of space-time, according to Albert Einsteins theory of general relativity: The Einstein field equations imply that any accelerated mass radiates energy this way, in the same way as the Maxwell equations that any...
Interferometry is the applied science of combining two or more input points of a particular data type, such as optical measurements, to form a greater picture based on the combination of the two sources. ...
The Michelson interferometer is the classic setup for optical interferometry and was invented by Albert Abraham Michelson and used for the famous Michelson-Morley experiment. ...
Since forming the arms in any case requires three widely separated spacecraft, the whole setup is made up of three identical spacecraft, each at the corner of a pair of arms, forming three complete interferometers; each arm is part of two interferometers. This requires that the arms be at 60 degrees to each other rather than the ideal 90 degrees, but it is easier to design and test only one type of spacecraft, and the redundancy helps to validate the data.
To eliminate non-gravitational forces such as light pressure and solar wind, each spacecraft is constructed as a zero-drag satellite. The end of each interferometer arm is defined by the mirrored surface of a free-floating internal "proof mass", and the surrounding spacecraft uses very precise thrusters to keep itself centered on the proof mass. Electromagnetic radiation exerts a pressure upon any surface exposed to it. ...
The plasma in the solar wind meeting the heliopause For the British comic, see Solar Wind (comic). ...
The entire arrangement, being ten times larger that the orbit of the Moon, will be placed in solar orbit, at the same distance from the Sun as the Earth, but trailing it by about 20 degrees. The mean linear distance between the constellation and the Earth will be 50 million kilometers. For other moons in the solar system see natural satellite. ...
A heliocentric orbit is an orbit around the sun. ...
The Sun is the spectral type G2V yellow star at the center of Earths solar system. ...
Earth is the third planet from the Sun. ...
The main goal of LISA is to study gravitational waves in detail. In this effort the LISA mission will test Einstein's theories about gravitational waves. Although most physicists believe that they do exist — there is indirect evidence by the increase of the orbital period of pulsars, such as the famous PSR 1913+16 — they have never been directly observed. The main reason for this is that their effect is extremely small. Observing them requires two things: a very large event generating the gravitational wave — such as a collapsing black hole — and extremely high detection sensitivity. The LISA instrument should be able to measure displacements with a resolution of 20 picometers over a distance of 5 million kilometers, yielding a strain sensitivity of better than 1 part in 10^20. Albert Einstein photographed by Oren J. Turner in 1947. ...
In physics, gravitational radiation is energy that is transmitted through waves in the gravitational field of space-time, according to Albert Einsteins theory of general relativity: The Einstein field equations imply that any accelerated mass radiates energy this way, in the same way as the Maxwell equations that any...
In 1993, the Nobel Prize in Physics was awarded to Russell Hulse and Joseph Taylor of Princeton University for their 1974 discovery of a pulsar, designated PSR B1913+16, in a binary system, in orbit with another star around a common center of mass. ...
A black hole is a concentration of mass so great that it takes forever to reach the surface. ...
Look up strain in Wiktionary, the free dictionary. ...
There are other gravitational wave telescopes already in operation on Earth, but their sensitivity at low frequencies is limited by practical arm lengths and interference from moving masses on the planet (e.g., logging operations and highway traffic around the telescope). Sine waves of various frequencies; the lower waves have higher frequencies than those above. ...
A single satellite ("LISA Pathfinder") is due to be launched in 2009 to validate the design and configuration of the definitive mission in 2012–2013. LISA Pathfinder is the revised name for SMART-2, an ESA space probe to be launched in 2008. ...
The mission is sponsored jointly between NASA (which will provide the launcher, the three spacecraft, and about half of the science payload) and the European Space Agency (providing the propulsion modules, and half of the science payloads through national contributions) under the Beyond Einstein program. NASA logo Listen to this article · (info) This audio file was created from an article revision dated 2005-09-01, and does not reflect subsequent edits to the article. ...
The European Space Agency (ESA), established in 1975, is an inter-governmental organisation dedicated to the exploration of space, currently with 17 member states. ...
The NASA Beyond Einstein program is a program designed to explore the limits of Einsteins theory of General Relativity. ...
See also The NASA Beyond Einstein program is a program designed to explore the limits of Einsteins theory of General Relativity. ...
The LIGO Hanford Control Room LIGO stands for Laser Interferometer Gravitational-Wave Observatory. ...
NASAs series of Great Observatories satellites were four large, powerful space-based telescopes. ...
Constellation-X, the Constellation X-ray Mission (formerly HTXS, the High Throughput X-ray Spectroscopy program) is a Next Generation X-ray Observatory dedicated to observations at high spectral resolution, providing as much as a factor of 100 increase in sensitivity over currently planned high resolution X-ray spectroscopy missions. ...
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