NAST Instrument

National Polar - Orbiting Operational Environmental Satellite System Airborne Sounder Testbed - Interferometer
(NAST-I) Instrument

Part of the  CIMSS  Web

Proteus Aircraft


The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Aircraft Sounding Testbed (NAST) is comprised of a suite of airborne infrared and microwave spectrometers.

NAST is being developed for the Integrated Programs Office (IPO) as part of a risk reduction effort for future instruments proposed to fly on the future NPOESS satellites and in turn it will provide the scientific community with valuable measurements of the atmosphere and surface from a high altitude platform.

The objectives of NAST are to provide airborne infrared and microwave spectral radiances during field experiments sufficient to: ER-2 Aircraft

NASA ER-2 high altitude research platform at Patrick AFB, FL during CAMEX-3 activities.

Both NAST-I and NAST-MTS (microwave spectrometer) are housed in the superpod.

NAST-I resides in the forward compartment of the superpod while NAST-MTS resides in the aft compartment.



The NAST-I is a high resolution Michelson interferometer, developed at MIT Lincoln Laboratory, that derives its heritage from the non-scanning High resolution Interferometer Sounder (HIS) developed by researchers at the University of Wisconsin Space Science and Engineering Center (UW-SSEC).The infrared radiance measurements obtained from the NAST-I instrument provide detailed spectral characteristics of the atmosphere and land surface which yield detailed atmospheric temperature and water vapor profiles derived from either physical or regression based retrieval algorithms.

NAST-I Flight Instrument Specifications

Spectral Resolution 0.25 cm-1
Spectral Response: LW 645 - 1300 cm -1
Spectral Response: MW 1290 - 2000 cm-1
Spectral Response: SW 1980 - 2700 cm-1
Spatial Resolution 2.6 km @ 20 km
Scan Width +/- 48o
Number of Elements/Scan Line 13 earth spots
NEDT < 0.1 - 0.25 K @ 260 K
Size Fits Super Pod
Weight 127 kg
Power 970 W
ER-2 Flight Location Super Pod



<- NAST-I Interferometer in the right forward compartment
of the ER-2 superpod and the NAST-I electronics package

Just aft of the Interferometer.
Images taken during CAMEX-3 activities August 8, 1998. ->



The NAST-M is a scanning microwave radiometer, which has a nadir ground resolution of ~2.5 km and scans from -58 to +78 degrees from nadir.

NAST-M Flight Instrument Specifications

Spectral Bands


Range (GHz)



WF Altitude (mm H2O)

Oxygen Band
50.3 - 56.02
0.19 - 0.23
0.07 - 0.08
Surface to 100 mb
Oxygen Line
118.75 +- 0.45 - 3.5
0.19 - 0.61
0.07 - 0.22
Surface (50 mm) to 80 mb
Water Line
166, 183.3 +- 1 - 10
0.25 - 0.6
0.09 - 0.22
(30 - 0.5)
Oxygen Line
424.76 +- 0.28 - 3.25
0.34 - 1.0
0.12 - 0.35
600 mb (3 mm) to 60 mb

NAST-M data products include