OPTIRAD (OPTImisation environment for joint retrieval of multi-sensor RADiances) aimed to advance the state of the art in EO data assimilation in land surface processes. The project built on existing tools and research results (EO-LDAS) to use EO data to improve estimation of some key environmental parameters, notably land surface and vegetation status, and carbon fluxes. The project implemented a Collaborative Research Environment for land data assimilation using ipython hosted on the Centre for Environmental Monitoring from Space (CEMS) computing environment.