Title: The Ocean Radiometer for Carbon Assessment (ORCA)
Author: Mark Wilson
Organization: NASA Goddard Space Flight Center
Co-Authors: Charles McClain, Michael Behrenfeld, Kenneth Blumenstock, Steven Brown, James Butler, Alan Holmes, Brian Martin, Timothy Madison, Gerhard Meister, Bryan Monosmith, Manuel Quijada, Peter Shu, Leroy Sparr, Eugene Waluschka

A design concept for an advanced ocean color radiometer, the Ocean Radiometer for Carbon Assessment (ORCA) has been underway at NASA Goddard Space Flight Center (GSFC) since 2002. In that time, the design has undergone a number of revisions and is now configured to meet all the measurement requirements for the Decadal Survey Aerosol, Cloud, and Ecology (ACE) ocean ecosystem radiometer (OES) and the PACE climate data continuity mission. With ROSES 2007 Instrument Incubator Program (IIP) support, the ORCA development team has pursued four objectives: (1) develop accurate sensor performance requirements and component specifications, (2) finalize the design and fabricate a functional prototype, (3) develop the sensor characterization test specifications and protocols that correspond to the performance requirements, and (4) conduct the component and system level characterizations. The prototype currently has flightlike fore and aft optics and scan mechanisms, but, due to cost constraints, nonflightlike commercial off-the-shelf (COTS) focal plane detector arrays including three shortwave infrared bands that have been added as required for ACE and PACE. While the COTS arrays cannot handle flight data rates, they are adequate for optical alignment and performance testing. Flightlike arrays and associated electronics will be designed, fabricated, and integrated into the prototype with funding from the ROSES 2010 IIP (work began in February). To date, all four objectives of the first IIP have been completed and the results are being documented. Complete sensor characterization was conducted at GSFC and The National Institute of Standards and Technology (NIST). The presentation will review the ORCA performance requirements, the basic design concept, and performance test results to date.