SIRAL: the radar altimeter for CryoSat mission, under development

SIRAL (SAR Interferometer Radar Altimeter) is the new spaceborne altimeter designed for CryoSat mission. The instrument is currently in the development phase, in ALCATEL SPACE, which encompasses an Engineering Model and a Flight Model. This ESA mission, planned for 2004, will be used to estimate - on a global scale - the fluctuations in mass of sea-ice and land-ice. This paper discusses the flexibility of the instrument and in particular its capability to operate in various modes (conventional altimeter, SAR and interferometer modes), and gives main results from the pre-developments and breadboard activities.