After the great success of LISA-Pathfinder, the pioneering mission launched on 3 December 2015 and set to conclude at the end of the month, the European Space Agency (ESA) has announced its plan to continue hunting for gravity waves.
The next step, officially confirmed a few days ago during a meeting of ESA’s Science Program Committee, is the actual construction of LISA - Laser Interferometer Space Antenna, scheduled to be launched in 2034. LISA will be among the large-scale missions included by ESA in its Cosmic Vision development program over the next twenty years.
ESA’s commitment to the study of gravitational waves is good news also for the University of Trento, where Stefano Vitale works as full Professor of Physics and member of TIFPA - Trento Institute for Fundamental Physics and Applications of the INFN, the principal investigator of LISA-Pathfinder who has been very involved in the project since the beginning.
«ESA’s green light is crucial for the mission», he commented. «LISA Pathfinder demonstrated that we can build a big interferometer, like the ground-based VIRGO-LIGO, but a thousand times bigger and, above all, space-born. And it will be more efficient and precise, not just more powerful. It will be able to detect waves from much heavier but also far more distant systems, like the collision of super-massive black holes which, it seems, played a key role in the history of the universe. This observatory, available to all researchers worldwide, will be a turning point in space observation».
This is also a personal accomplishment for Stefano Vitale, who has recently been appointed President of ESA’s Science Program Committee for his dedication and the successes achieved by the LISA mission. The Committee, which comprises a delegation from every European country, oversees ESA’s mandatory science program. The appointment as president is one of great significance. A position held in the past by prominent physicist Edoardo Amaldi, one of the first to conduct research on gravitational waves who was responsible for the renaissance of Italian physics and the launch of important transnational projects (among which, in particular, CERN).
With Vitale as President, there could be more good news coming for the physics department in Trento. First of all, Vitale will hand the leadership of the Italian effort to Bill Weber, a physicist at the University of Trento, who will be co-principal investigator of the project. The research group, embedded in the Physics department of the University of Trento and in the Trento Institute for Fundamental Physics and Applications (TIFPA), will continue to play an important role in the Lisa mission too, thanks to Rita Dolesi who, working closely with INFN, will be part of ESA’s task force for the development of the gravitational sensor provided by Italy.
LISA: looking forward to 2034
LISA Pathfinder, the pioneering mission, will come to an end in June, while the LISA mission will begin the study phases that precede the second decision-making round, which will be followed by the go-ahead to the construction and launch of the mission. These are therefore fundamental steps for the three crafts that will detect gravitational waves. They will work together, each 2.5 million kilometres from the next, in a triangular formation orbiting around the Sun, some 50 million kilometres from the Earth, looking for ripples in the space-time generated by incredibly massive objects, like two merging black holes.
Each of the three satellites on LISA will contain two free-floating test masses, totally isolated from external or internal forces, and linked by a laser beam, like in the Lisa Pathfinder mission. This is a key technology to detect any distortion caused by the passage of gravitational waves. To reveal any sign of gravitational waves, the test masses must be protected from all possible sources of distortion while free-floating and must be isolated from external or internal forces, except gravity. The purpose of the project is to identify with the utmost precision these minuscule changes in the space-time, on scales less than a millionth of a millionth of a metre.
For more information on LISA, read ESA’s press release