Title of Paper: AIRS-Light Instrument Concept and Critical
Technology Development
Principal Author: Dr. Kevin Maschhoff
Abstract: Understanding Earth's climate, atmospheric
transport mechanisms, and the hydrologic cycle requires a precise knowledge of
the global atmospheric circulation, temperature profiles, and water vapor
distribution. The accuracy of advanced sounders such as AIRS/AMSU/HSB on NASA's
Aqua spacecraft can match radiosonde accuracy. It is essential to fold those
capabilities fully into the NPOESS, enabling soundings of radiosonde accuracy,
every 6 hours around the globe on an operational basis. However, the size,
mass, power demands, and thermal characteristics of the Aqua sounding
instrument suite cannot be accommodated on the NPOESS spacecraft.
AIRS-Light is an instrument concept, developed under the Instrument
Incubator Program, which provides IR sounding performance identical to the AIRS
instrument, but uses advances in HgCdTe FPA technology and pulse tube cooler
technology, as well as design changes to dramatically reduce the size, mass,
and power demand, allowing AIRS-Light to meet all NPOESS spacecraft interface
requirements. The instrument concept includes substantial re-use of AIRS
component designs, including the complex AIRS FPA, to reduce development risk
and cost. The AIRS-Light Instrument Incubator program fostered the development
of photovoltaic-mode HgCdTe detector array technology for the 13.5-15.4
micrometer band covered by photoconductive-mode HgCdTe arrays in AIRS, achieved
state of the art results in this band , and substantially reduced the
development risk for this last new technology needed for AIRS-Light
implementation.
A demonstration of a prototype 14.5-15.4 micrometer band IRFPA in a reduced
heat-load dewar together with the IMAS pulse tube cryocooler is in progress.
This paper will include a summary of the AIRS-Light instrument concept and of
the advances in very long wavelength PV HgCdTe technology which enable
AIRS-Light.