A Geostationary Gravitational Wave Interferometer (GEOGRAWI)
  We propose a Geostationary Gravitational Wave Interferometer (GEOGRAWI) mission concept for making observations in the sub-Hertz band. GEOGRAWI is expected to meet some of LISA's science goals in the lower part of its accessible frequency band ($10^{-4} - 2 \times 10^{-2}$ Hz), and to outperform them by a large margin in the higher-part of it ($2 \times 10^{-2} - 10$ Hz). As a consequence of its Earth-bound orbit, GEOGRAWI is significantly less expensive than the interplanetary LISA mission and could be either an entirely US mission or managed and operated by NASA in partnership with the Brazilian Space Agency. 
Massimo Tinto, J. C. N. de Araujo, Odylio D. Aguiar, Eduardo da Silva   Alves
astro-ph.IM gr-qc