Title: Approaching the finish line with GeoSTAR
Presenting Author: Bjorn Lambrigtsen
Organization: Jet Propulsion Laboratory
Co-Author(s): Todd Gaier, Alan Tanner, Pekka Kangaslahti, Boon Lim (JPL); Chris Ruf, Mike Flynn (U. Michigan

Abstract:
The Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR) is a microwave sounder intended for the Precipitation and All-weather Temperature and Humidity (PATH) mission. PATH is one of 15 missions that the National Research Council (NRC) recommended in 2007 that NASA undertake in the ensuing decade and consists of placing a microwave sounder on a geostationary satellite to observe rapidly evolving atmospheric processes such as hurricanes and other severe weather. The NRC further recommended that the PATH sensor be implemented with a "microwave array spectrometer". The GeoSTAR design then under development through the Instrument Incubator Program, IIP-03, was and still is the only array spectrometer solution, and NASA has therefore continued to fund advancement of the technology required to implement GeoSTAR for PATH, in IIP-07 and now in IIP-10. By the end of IIP-10 in early 2015 the maturity of all key technologies will be sufficient that the development of the PATH mission can commence. The toughest challenge has been to develop a correlator ASIC that can meet the PATH requirements for speed and power consumption. Such a chip has now been developed with the help of our colleagues at the University of Michigan. Secondary goals have been to build a complete fully functional 183-GHz array of miniature high performance receivers, which are assembled by NexGen through an SBIR contract, using LNAs developed in collaboration with NGC and fabricated by them. While the IIP-10 developments are needed to fully enable the PATH development, the technology is already sufficiently advanced that the development of a small pre-PATH mission can be initiated now, and we anticipate that such a mission could be funded through the Venture program in the near future. The full PATH mission is currently classified as a tier-3 mission, but with the rapid progress in the technology development, it is now feasible to advance PATH to the pre-formulation phase. We will discuss the specific advances in the technology achieved so far. Copyright 2014 California Institute of Technology. Government sponsorship acknowledged.