The design is similar to LISA, with four zero-drag satellite clusters (two colocated) in a triangular arrangement, but using a smaller separation of only 1000 km whose relative displacements are measured by a Fabry–Pérot Michelson interferometer.
[4] The first mention of the observatory as "DECIGO" was in a presentation given by Naoki Seto, Kawamura, and Takashi Nakamura at a September 2001 meeting of the Physical Society of Japan at Okinawa International University.
[5] It was designed as a follow-up project to KAGRA by the Japanese Gravitational Wave Community (JGWC), and it was originally planned to be launched in 2027.
[1] A 2008 paper in the Journal of Physics: Conference Series in 2008, authored by 135 scientists headed by Kawamura, went into significantly more detail, describing the basic initial design ideas.
It will consist of a single cluster of observatories, each having arm lengths of 100 kilometres (62 mi), a laser wattage of 1 (rather than the 10 watts used for DECIGO), and a mirror mass of 30 kilograms (66 lb).