We are developing a new remote sensing system at the University of Arizona called the Active Temperature, Ozone and Moisture Microwave Spectrometer (ATOMMS). ATOMMS combines many of the best features of GPS Radio Occultation (RO) and the Microwave Limb Sounder (MLS) by actively probing cm to sub-mm wavelength atmospheric absorption features via satellite-to-satellite occultation. ATOMMS will provide an unprecedented combination of features for monitoring climate from orbit. With funding from NSF and aircraft time from NASA, we will demonstrate the ATOMMS concept via high altitude aircraft-to-aircraft occultations in 2011. Here we summarize the ATOMMS concept and demonstration project and provide early test results from the instrument indicative of ATOMMS capabilities and performance.