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This is an artists concept showing gravitational waves.

LISA and Changes in the Cosmic Vision Programme.

April 8, 2011. Based on discussions with the European Space Agency (ESA) at the recent ESA-NASA bilateral meeting, we can provide the following information concerning LISA. Readers should refer to this ESA posting for details and clarifications regarding the Cosmic Vision Programme.

LISA was competing with X-ray and outer-planets missions for the L1 opportunity in ESA's Cosmic Vision Programme (2015-2025). The U.S. decadal survey rankings and NASA's constrained out-year resources, as projected in the President's FY12 Budget Request, have led ESA to conclude that none of the three mission concepts were feasible within the Cosmic Vision L1 schedule.

ESA has ended the study of LISA and the other concepts as partnerships at the scale proposed in the New Worlds New Horizons decadal survey (NWNH). ESA has begun a rapid definition effort that includes the formation of a new science team (to be announced shortly). That effort will identify science goals and a mission concept that can be implemented as part of an ESA-led mission launching in the early 2020's. Revised mission concepts from the three science areas will be considered in a selection process commencing in February 2012.

A future minor role for NASA in the ESA-led mission has not been ruled out. NASA will participate in the new ESA science team through a "NASA-HQ empowered scientist." That representative will be a civil servant scientist who will act as conduit for input from and information to the US science community.

NASA's Astrophysics Division plans to continue basic funding for the LISA study team through FY11, assuming not-larger-than-anticipated cuts from Congress. The Division will engage the community about strategic investments in gravitational wave astrophysics and possible solicitations for new concept studies, in the context of NWNH recommendations and projected resources. A US science team will be asked to provide input from the community on the way forward in gravitational-wave astronomy including scientific and technical assessments.

Gravity is talking. LISA will listen.

The Cosmos sings with many strong gravitational voices, causing ripples in the fabric of space and time that carry the message of tremendous astronomical events: the rapid dances of closely orbiting stellar remnants, the mergers of massive black holes millions of times heavier than the Sun, the aftermath of the Big Bang. These ripples are the gravitational waves predicted by Albert Einstein's 1915 general relativity; nearly one century later, it is now possible to detect them. Gravitational waves will give us an entirely new way to observe and understand the Universe, enhancing and complementing the insights of conventional astronomy.

LISA, the Laser Interferometer Space Antenna, is a joint NASA–ESA mission to observe astrophysical and cosmological sources of gravitational waves of low frequencies (0.03 mHz to 0.1 Hz, corresponding to oscillation periods of about 10 hours to 10 seconds). This frequency band contains the emission from massive black-hole binaries that form after galactic mergers; the song of compact stellar remnants as they slowly spiral to their final fate in the black holes at the centers of galaxies; the chorus of millions of compact binaries in our own Galaxy; and possibly the faint whispers of waves generated shortly after the Big Bang.

LISA consists of three identical spacecraft flying in a triangular constellation, with equal arms of 5 million kilometers each. As gravitational waves from distant sources reach LISA, they warp space-time, stretching and compressing the triangle. Thus, by precisely monitoring the separation between the spacecraft, we can measure the waves; and by studying the shape and timing of the waves we can learn about the nature and evolution of the systems that emitted them.
Science title
LISA will unveil the dark side of the Universe by observing thousands of gravitational-wave sources.
Mission title
LISA will detect gravitational waves by accurately monitoring the separation between three widely separated spacecraft.
Technology title
LISA will employ laser interferometry and drag-free operation to measure the distances between freely-falling test masses protected by the spacecraft.

LISA under study as a European-only mission

Watch the new LISA movie at the AEI website

LISA Pathfinder passes critical design review