Under WRC-07 Agenda item 1.7, Resolution 744 (WRC-03) requests studies into sharing between the mobile satellite service and space research(passive) service in the band 1 668-1 668.4 MHz. Two relevant space-VLBI (Very Long Baseline Interferometry) systems have been identified. The HALCA system began operation in 1997 and ceased operation in 2005. A proposed system, Radioastron, is planned for this band and characteristics have been made available.