This IRAD (Internal Research and Development) project was conceived as an aircraft instrument and designed with specifications that are closely aligned with the science requirements of the Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission. The work has been used to both advance the technology readiness as well as refine the discipline science measurement requirements for the GEO-CAPE effort. The project consisted of integrating a two-channel UV/VIS/NIR spectrograph with command and control hardware and environmental enclosure suitable for autonomous flight onboard the Langley B-200 and other airborne platforms.
The system has been used as a successor/upgrade to the Airborne Compact Atmospheric Mapper (ACAM) that has been deployed as part of the Discover-AQ Earth Venture program. The Air Quality science objectives of this program overlap nicely with GEO-CAPE science requirements. GCAS has successfully flown on two extended field missions for Discover-AQ.
The questions that an airborne simulator can answer fall into both technology advancement and scientific algorithm development categories, and are linked in an iterative process throughout the development cycle of a new mission concept. The GCAS can help steer technology development resources towards the most appropriate detector format and technology, for example. The high spatial and temporal resolution, and high dynamic range requirements of trace-gas and ocean radiances from a geostationary platform will require careful design and qualification of flight detectors. An airborne simulator will replicate all of the ground scene characteristics that a Geo instrument will have to contend with. In addition to the technology aspect, there are valuable test cases an airborne simulator can address in defining capabilities for science retrievals in the presence of clouds and aerosols with high-spatial-resolution measurements. Airborne campaigns are also invaluable as calibration and validation exercises, and have unique advantages in planning for post-launch Cal/Val and how to assemble and design a Cal/Val program around the appropriate ground and sub-orbital assets.
This work was done by Scott Janz and John Riley of Goddard Space Flight Center, and Matt Kowalewski of USRA. GSC-16961-1