BRIX-2 represents a joint effort to intercompare algorithms specifically for biomass mapping using current and future spaceborne missions (GEDI;NISAR and BIOMASS). These objectives shall be achieved by making available standardised test cases supported by the ESA/NASA MAAP (based on airborne campaign and spaceborne simulated data);inviting the scientific community to develop and apply retrieval algorithms based on this test case;and finally compare and evaluate the performance of submitted results. Two workshops will be conducted;the first one to define the exercise (in Jan/Feb 2021 - tbc) and the second one to discuss the results. The evaluation will be done by ESA/NASA following the CEOS WGCV LPV guidelines. The outcome of the exercise will be published in peer-reviewed literature.