The purpose of the `evolved Laser Interferometer Space Antenna (eLISA)` project is to detect gravitational waves.

Gravitational waves are ripples in the fabric of spacetime, predicted by Einstein`s theory of general relativity. These waves are generated by the motion of massive objects, such as black holes and neutron stars, and carry information about their properties and interactions. The detection of gravitational waves would provide a new way to study the universe, allowing us to observe phenomena that are invisible to traditional telescopes.

eLISA is a space-based gravitational wave observatory that is currently under development by the European Space Agency (ESA), in collaboration with NASA. It is an evolved version of the Laser Interferometer Space Antenna (LISA) mission, which was originally proposed in the 1990s but was never launched.

eLISA will consist of three spacecraft that will orbit the sun in a triangular formation, with arms that will extend over millions of kilometers. These arms will contain laser interferometers that will measure the tiny distortions in spacetime caused by passing gravitational waves. By detecting these waves, eLISA will be able to study a wide range of astrophysical phenomena, including the mergers of black holes and neutron stars, the formation of galaxies, and the evolution of the universe.

In summary, the purpose of the eLISA project is to detect gravitational waves and use them to study the universe in a new way, providing insights into some of the most mysterious and fascinating phenomena in astrophysics.