SAFIRE-A (spectroscopy of the atmosphere by far-infrared emission--airborne): optimized instrument configuration and new assessment of improved performance

An upgraded configuration of the SAFIRE--A Fourier transform far-infrared spectrometer was recently set up, and significant improvements in instrument performance were attained during several testing and scientific flights onboard the high-altitude research aircraft M55-Geophysica. New features were implemented in specific instrument subsystems, such as the pointing system, the reference laser interferometer, and the onboard calibration unit, to increase the overall instrument functionality and to obtain reliable operation from both the high-frequency (-120 [cm.sup.-1]) and the low-frequency (-23 [cm.sup.-1])detection channels. Other changes, such as those made in the onboard recording system or in the postflight data-transfer procedure, were aimed at expanding the capability of unattended operation and at providing a user-friendly interface for data downloading and ground servicing. A detailed description of these modifications is given, along with a quantitative assessment of the SAFIRE--A instrument performance. [c] 2004 Optical Society of America OCIS codes: 300.6300, 300.2140, 280.0280, 010.1280.