Introduction | Mission Description | All About Gravitational Waves | Mission Benefits
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Artist's concept of the LISA mission.
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How
did the Universe begin? Does time have a beginning and an end? Does
space have edges? These are the questions we've struggled to answer for
centuries. Science and technology have now reached the point where
answers to these questions are finally within our grasp. The Laser
Interferometer Space Antenna (LISA) may supply some of these answers as
the mission studies the mergers of supermassive black holes, tests Einstein's Theory of General Relativity, probes the early Universe, and searches for gravitational waves——the primary objective.
As the first dedicated space-based gravitational wave observatory, LISA will detect waves generated by binaries within our Galaxy, the Milky Way,
and by massive black holes in distant galaxies. Although gravitational
wave searches in space have previously been made, they were conducted
for short periods by planetary missions that had other primary science
objectives. Some current missions are using microwave Doppler tracking to search for gravitational waves. However, LISA will use an advanced system of laser interferometry for detecting and measuring them. And, LISA will directly
detect the existence of gravitational waves, rather than inferring it
from the motion of celestial bodies, as has been done previously.
Additionally, LISA will make its observations in a low-frequency band
that ground-based detectors
can't achieve. Note that this difference in frequency bands makes LISA
and ground detectors complementary rather than competitive. This range
of frequencies is similar to the various types of wavelengths applied
in astronomy, such as ultraviolet and infrared. Each provides different
information.
In
space, LISA won't be affected by the environmental noise that affects
ground detectors on Earth's surface. Due to earthquakes and other
vibrations, ground detectors can only make observations at frequencies
above 1 hertz. However, other environmental factors will impact
LISA. Such factors include the drift of the spacecraft, charging of the
test masses, and buffeting by the solar wind. Making these small
disturbances negligible is a technological challenge of the mission.
Meeting this challenge will help to ensure the detection of
gravitational waves.
LISA is jointly sponsored by the European Space Agency (ESA), as a Cornerstone mission in ESA's Cosmic Vision Programme, and NASA's Astronomy and Astrophysics Division, as part of the Structure and Evolution of the Universe 2003 roadmap, "Beyond Einstein: From the Big Bang to Black Holes." This program studies the building blocks of our own existence at the most basic level: the matter, energy, space, and time that make up the Universe. LISA is one of the program's Great Observatories.
In
this cooperative venture, ESA is providing the three spacecraft and
their propulsion modules, the gravitational reference sensors, some
interferometry components, and the laser subsystems. NASA is providing
the launch vehicle, some interferometry components, and the
spacecraft's telecommunications systems. NASA will also perform payload
integration and testing. Goddard Space Flight Center is managing the project. The mission will be operated from the Jet Propulsion Laboratory.
NASA and ESA have had a formal agreement to jointly pursue LISA formulation since 2001. The LISA mission is currently under study at NASA, where it is part of the Physics of the Cosmos theme. The ESA formulation study started in 2006. The two agencies anticipate launch in the 2019-2020 time frame, with a total mission duration of five to eight years. Once in
orbit, LISA's observations will help us to better understand the
fundamental physical laws of the Universe, as well as how it began.
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