Although conceived about 30 years ago as part of NASA’s “Mission to Planet Earth”, the routine monitoring of temporal and spatial variation in the Earth’s soil moisture at global scale is just becoming a reality. In November 2009 the European Space Agency launched the first-ever satellite dedicated to the measurement of soil moisture, known as the Soil Moisture and Ocean Salinity (SMOS) mission, and NASA is developing the Soil Moisture Active and Passive (SMAP) mission that will provide soil moisture at higher spatial resolution, with a planned launch of 2014. However, data from the SMOS satellite need to be validated using detailed field campaign data, and techniques must be matured to increase the spatial resolution and depth of this soil moisture information from SMAP. Using a unique airborne simulator, the pre-launch soil moisture retrieval algorithms for SMOS have been extensively tested using detailed ground measurements and airborne observations from a series of intensive field campaigns undertaken in Australian soil moisture observatories. Moreover, an extensive validation campaign has just been undertaken in the Murrumbidgee soil moisture observatory, representing a typical slice of Australia. By accurately mapping the spatial variability across an area comprising more than 20 independent SMOS pixels, this extensive airborne campaign provides not only the first, but likely also the most comprehensive validation of observed brightness temperatures and derived soil moisture from the SMOS mission. Likewise, pre-launch development and testing of the SMAP algorithms are under way using Australian campaign data. Once validated, the soil moisture monitoring information that these satellites provide will be used to constrain numerical model predictions, thus providing a real-time soil moisture monitoring and prediction capability for Australia, leading to improvements in weather prediction, flood forecasting, drought monitoring, water accounting and agricultural productivity.