The PARASOL mission intends to characterize the radiative properties of clouds and aerosols by exploiting its complementarity with the other instruments in the A-Train formation, which include the CERES and MODIS radiometers on the AQUA satellite, the lidar on CALIPSO and the radar on CLOUDSAT.
The AQUA, CALIPSO and CLOUDSAT missions are intended to fulfil this purpose by collecting measures in differents spectral domaines (optical and microwave) accessibles to spatial observation, and by combining measures covering larges fields of viewwith punctual measures.
PARASOL, with its ability to measure directional charactéristics and light polarization reflectances from land surfaces, will complete the measures collected by the other missions.
The PARASOL mission purpose is to perform measurements of the polarized and multi-directional reflectances, on areas observed by the LIDAR on board CALIPSO as a priority.
The synergy between the AQUA, CALIPSO, CLOUDSAT and PARASOL missions imply three major constraints on this mission, which are :
the orbit characteristics that are set to :
a 705 km altitude,
a 98,21° declination (AQUA) or a 98,08° declination (CALIPSO),
the equator time crossing which must be in concordance with the AQUA (13h30) and CALIPSO time crossing (set between 14h10 at the beginning of the mission and 12h50 at the end),
the launch, which must take place during the activity phase of the constellation other satellites,
the synergies to achieve on the mission centers, for the orbit control as well as the scientific data processing.