Some basic principles of a “LISA”

A Laser Interferometer Space Antenna (LISA) is a concept studied and developed since a few decades both by European and American teams. Its aim is to study the gravitational wave signals emitted by astrophysical sources such as supermassive black hole (SMBH) coalescences, captures of compact objects by SMBHs, compact galactic binaries, etc. The LISA mission has been first an ESA/NASA mission (1998–2011), then became an ESA mission under the name of NGO (2012): it could hopefully be proposed for selection in 2013. The very basic principles of such a mission still deserve a presentation, being quite generic: this is the aim of the present article.