Spectral Sciences Incorporated

About: Spectral Sciences Incorporated is a company organization based out in Burlington, Massachusetts, United States. It is known for research contribution in the topics: Hyperspectral imaging & Radiance. The organization has 114 authors who have published 342 publications receiving 10875 citations.

Photometric analysis of a space shuttle water venting

Abstract: Presented here is a preliminary interpretation of a recent experiment conducted on Space Shuttle Discovery (Mission STS 29) in which a stream of liquid supply water was vented into space at twilight. The data consist of video images of the sunlight-scattering water/ice particle cloud that formed, taken by visible light-sensitive intensified cameras both onboard the spacecraft and at the AMOS ground station near the trajectory's nadir. This experiment was undertaken to study the phenomenology of water columns injected into the low-Earth orbital environment, and to provide information about the lifetime of ice particles that may recontact Space Shuttle orbits later. The findings about the composition of the cloud have relevance to ionospheric plasma depletion experiments and to the dynamics of the interaction of orbiting spacecraft with the environment.

Automated remote monitoring of toxic gases with diode-laser-based sensor systems

Abstract: Spectral Sciences has developed a family of automated remote gas sensors including a long-path absorption system, and a fiber- optic-based system utilizing multiple remote-sensing heads. Results are presented from initial field tests of the long-path sensor.

Diode laser system for monitoring chemical species

Abstract: An off-line-locked laser diode species monitor system comprises: reference means (52) for including at least one known species having a first absorption wavelength; a laser source (12) for irradiating the reference means and at least one sample species having a second absorption wavelength differing from the first absorption wavelength by a predetermined amount; means (2) for locking the wavelength of the laser source to the first wavelength of the at least one known species in the reference means; a controller (50) for defeating the means for locking and for displacing the laser source wavelength from said first absorption wavelength by said predetermined amount to the second absorption wavelength; and a sample detector device (40) for determining laser radiation absorption at the second wavelength transmitted through the sample to detect the presence of the at least one sample species.

Enhanced Target Detection Under Poorly Illuminated Conditions

Abstract: We demonstrate an enhanced ACE target detection algorithm for poorly illuminated and shadowed pixels in which image segmentation based on illumination is performed prior to target detection. This enhanced ACE detection method (ACE-shadow) relies on FLAASH-based scene atmospheric correction and MODTRAN-calculated direct to diffuse illumination ratios to model shadowed target spectra. Improvements to target detection were realized using our ACE-shadow detection algorithm because SNR characteristics of shadowed pixels dominate the segmented covariance.

Chemical and Flowfield Modeling for Enhanced Analysis of Contamination Experiments

Abstract: This paper describes the application of a new Direct Simulation Monte Carlo (DSMC) code, the Molecular Beam Simulator (MBS), which is designed to analyze laboratory scale molecular beam-surface (and crossed-beam) experiments. The MBS is primarily intended to model experiments associated with spacecraft contamination effects, but it can also be used to simulate a variety of surface chemistry and reactive flow measurements. The MBS code is fully three-dimensional, includes a wide-range of chemical processes, and can model one or multiple pulsed (non-steady) sources. As an example application of the MBS code, a fast, pulsed, oxygen atom-surface experiment which examines the chemistry behind erosion of graphite by oxygen atoms is analyzed. Unsteady DSMC simulations show that experimental observations of excited molecular states after the pulse has hit the surface are consistent with two distinct chemical mechanisms: a direct one where the excited molecules are formed on the surface, and a two-step mechanism where ground state molecules formed on the surface are collisionally excited after they leave the surface by trailing oxygen atoms in the pulse. Further DSMC calculations suggest experiments which can distinguish between these mechanisms.