Title: The NASA Enhanced MODIS Airborne Simulator (eMAS)
Author: Jeff Myers
Organiztion: University of California, Santa Cruz
Co-Authors: Thomas Ellis

The NASA Enhanced MODIS Airborne Simulator (eMAS) is scheduled for completion in late 2011. Partly based on the legacy MAS system, in use since 1995 by the NASA Earth Observing System program, eMAS consists of two separate instruments (eMAS-IR and eMAS-HSI) designed to fly together on the NASA ER-2 and Global Hawk high altitude research aircraft.

The eMAS-IR instrument is an upgraded version of the legacy MAS line-scanning spectrometer, with 38 spectral bands in the wavelength range from 0.47 to 14.1 µm. The original LN2-cooled MAS MWIR and LWIR spectrometers are replaced with a single vacuum-sealed, Stirling-cooled assembly, having a single MWIR and twelve LWIR bands. This spectrometer module contains a cold optical bench where both dispersive optics and detector arrays are maintained at cryogenic temperatures to reduce infrared background noise, and ensure spectral stability during high altitude airborne operations.

The EMAS-HSI instrument is a stand-alone push-broom imaging spectrometer, with 202 contiguous spectral bands in the wavelength range from 0.38 to 2.40 mm. It consists of two Offner spectrometers, mated to a 4-mirror anastigmat telescope. The system has a single slit, and uses a dichroic beam-splitter to divide the incoming energy between VNIR and SWIR focal plane arrays. It will be synchronized and bore-sighted with the IR line-scanner, and includes an active source for monitoring calibration stability.

eMAS is intended to support future satellite missions including the Hyperspectral Infrared Imager ( HyspIRI,) the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP,) and the follow-on Joint Polar Satellite System (JPSS.) This is an ARRA-funded project, through the NASA Earth Science Technology Office.