LISA selected as ESA L3 mission
Decision by ESA’s Science Programme Committee puts mission on track for 2034 launch
June 22, 2017
“After 25 years of hard work, developing and planning our gravitational-wave detector in space, I am very pleased to witness this day which marks the birth of the LISA mission. LISA will be a unique observatory and will revolutionize our understanding of the Universe,” says Karsten Danzmann, director at the Max Planck Institute for Gravitational Physics Hannover and director of the Institut für Gravitationsphysik at Leibniz Universität Hannover. “With LISA we might be able to listen to the echo of the Big Bang, and will hear the sounds of supermassive black hole pairs merging anywhere in the entire Universe.”
Gravitational-wave observation from space
Einstein predicted the existence of gravitational waves from his theory of general relativity. They were – 100 years after their prediction – observed for the first time by the ground-based Advanced LIGO detectors in September 2015. Two other clear detections followed. Space-borne observatories such as LISA will complement the existing ground-based detectors by measuring low-frequency gravitational waves inaccessible from Earth.
The signals seen by ground-based detectors have frequencies between tens of Hertz and several kilohertz, but gravitational waves span a much wider spectrum. In particular, lower frequency waves are produced by events such as the mergers of supermassive black holes millions or billions times the mass of our Sun, millions of binary stars in our Galaxy, or exotic events such as cosmic strings.
LISA Pathfinder paved the way
Detecting the gravitational waves emitted from these events at frequencies between 0.1 millihertz and 1 Hertz requires measuring the distance changes between objects placed millions of kilometers apart to a picometer. This can only be achieved in space, where an observatory would also be free of the seismic, thermal, and terrestrial gravity noises that limit ground-based detectors.
LISA Pathfinder is an ESA satellite mission, designed to demonstrate key technologies needed to build LISA. It has proven those technologies beyond any doubt and has exceeded all expectations. At the end of June, after sixteen months of science operations, LISA Pathfinder will complete its mission.
Building and launching LISA
In 2013 ESA chose the “Gravitational Universe” science theme for its L3 mission. The 20th of June selection of the LISA mission is the second step towards a gravitational-wave observatory in space. Now, the design specifications of the mission will be completed and the costs will be evaluated. Finally, the mission will be proposed for “adoption” by ESA, followed by the construction of the spacecraft. The launch of the three satellites is scheduled for 2034. The science measurements of LISA would begin about one year after launch and the science mission is planned to last at least 4 years and could be extended to last for as long as 10 years.