Gravitational Waves

"An Ear to the Big Bang," by Ross D. Andersen, discusses various strategies being studied in the U.S. to develop space-based gravitational-wave observatories but fails to mention the eLISA mission concept, a strong candidate for the European Space Agency's next large mission. eLISA is a descendant of the Laser Interferometer Space Antenna (LISA) mission concept mentioned in the article. Europe has also made a particularly strong investment with the LISA Pathfinder mission, set to launch in 2015, which will demonstrate technological readiness and provide Europe with the opportunity to lead the first space-based gravitational-wave mission. No other competitive concept for such a mission currently exists.