Aqua, runs 4 minutes behind GCOM-W1, launched for NASA on May 4, 2002. CALIPSO, a joint effort of CNES and NASA, follows CloudSat by no more than 15 seconds, launched on April 28, 2006. Aura, a multi-national satellite, lags Aqua by 15 minutes, crossing the equator 8 minutes behind due to different orbital track to allow for synergy with Aqua, launched for NASA on July 15, 2004.