Earlier this year, researchers declared the discovery of gravitational waves, Einstein’s waves in space-time, for the first time on Earth. Those waves are now deep through NASA, pushing the agency to restore fences with the European Space Agency (ESA) and rejoin an aspiring mission, called the Laser Interferometry Space Antenna (LISA), to discover gravitational waves from space. This week, at the 11th Laser Interferometry Space Antenna (LISA) conference in Zürich, Switzerland, a NASA official said he was prepared to rejoin the Laser Interferometry Space Antenna mission, which the agency left in 2011. For now, European Space Agency (ESA) states it is working to postpone the launch of the mission up few years from 2034.
David Shoemaker, a gravitational wave physicist at the Massachusetts Institute of Technology (MIT) in Cambridge, says, "This is a very important conference. It appears to be a turning point".
Tactics and plans for LISA date back more than twenty years. Three separate spacecraft, flying millions of km separately from each other at the vertices of a huge triangle, would exactly measure their common separations using complex lasers, and thus be capable of spotting low-frequency waves in space-time. The stuff causing these low-frequency waves, such as revolving supermassive black holes at the centers of distant galaxies, would not be the same from the higher frequency waves, radiated by impacts of much smaller black holes that have so far been spotted on Earth.
At first, LISA was considered as a joint ESA-NASA mission. Both partners (ESA and NASA) would pay 50 percent of the mission charges, predicted at some $2 billion. But in April 2011, NASA dropped out of the partnership because of economical problems, and the mission was nearly killed.
Astro-physicist Paul McNamara of ESA’s space research and technology center ESTEC in Noordwijk, in Netherlands, "The next year, the LISA session sensed like a funeral," remembers.
Then, in 2013, a cut-down, €1 billion type of LISA was nominated by ESA as its L3 mission, the third large mission in its Planetary Vision 2020 program. Called eLISA (where the “e” indirectly stands for “evolved”), it would have the fewer capability and sensitivity than the initial design. The launch was predicted in 2034. NASA expressed curiosity to become a minor partner, volunteering technological support.
But things are different a lot now, in the past few years. ESA’s technology demonstrator LISA Pathfinder, launched in December 2015, has performed perfectly, says McNamara, who is the mission’s project scientist. Then, in February, the ground founded Laser Interferometer Gravitational-Wave Observatory experiment stated that it had taken its first direct detections.
In June, a NASA-appointed L3 Study Team offered its interim report, proposing ways for the agency to rejoin the program as a high-ranking partner. And on 15 August, a mid-term assessment of the National Academy of Sciences’s (NAS) 2010 Decadal Report, which analyses U.S. priorities for astronomy and astrophysics, intensely recommended NASA to give back support to the space observatory this decade and to help rejoin the mission to its original complete capacity.
It now appears like the recommendations are taking effect. At the Zürich conference, Paul Hertz, the director of NASA’s astrophysics division, said: "2011 was the turning and as well finishing point of our Laser Interferometry Space Antenna (LISA) partnership. But I am here to go forward from that." NASA’s involvement may not get back to 50%, but according to the report of National Academy of Sciences (NAS), what’s compulsory is "a significantly larger U.S. partnership than the $150 million […] currently being measured."
For now, ESA’s Director of Science Alvaro Giménez in Madrid stated that the call for mission perceptions for eLISA will be carried forward from 2018 to next month. “We want to make your dreams come true,” he told the gravitational-wave researchers at the meeting. "Though 2029 is possibly too optimistic, we may be capable of launching the mission a few years earlier, somewhere in the early 2030s." According to Giménez, not re-establishing a much stronger corporation with NASA is now almost unthinkable.
Researchers at the conference were happy. Karsten Danzmann of the Albert Einstein Institute in Hannover, Germany, says, "When we launch 14 or 15 years from today, this meeting or session will be seen as the re-birth of LISA", he is LISA Pathfinder’s co-principal investigator.