Scheme design and key technology verification of Narrow Angle Sensor for small body mission

<p>   In small body exploration mission, the uncertainty of the target characteristics and the special weak gravitational environment put forward higher requirements for the optical autonomous navigation accuracy of the probe and the detection ability of the navigation sensor. Narrow Angel Sensor(Hereinafter referred to as NAS), as the key instrument of China’s first small body exploration mission, has both optical autonomous navigation function and scientific observation ability, and it must give consideration to both near and far, and achieve breakthroughs in dynamic range, detection sensitivity, pointing measurement accuracy, angular resolution and spectral observation ability. The specific performance is as follows: To capture and track Near Earth Asteroids 2016HO3 from tens of thousands of kilometers, NAS is required to have the ability of point target detection, and the detection sensitivity is better than MV10, and  the accuracy of pointing measurement is better than 1 ″. As the probe approaches the target, NAS must be able to clearly image the shape and surface texture of 2016HO3, so as to obtain the motion parameters such as the spin axis and rotation period of the target. In remote sensing and descending stage, the mission requires NAS to be able to carry out global centimeter scale and landing area millimeter scale multi-spectral observation of the target, and optical navigation uses high-resolution images to construct landmark feature library, so as to realize terrain relative navigation; meanwhile, the image is used to provide data support for the scientific research of the target topography, spectral characteristics and surface material composition analysis.</p> <p>   NAS adopts split design, and the detector part is composed of front door, baffle, focusing optical system, filter wheel, image processing circuit, and motor drive circuit, the algorithm is implemented in the image navigation processing unit. The prototype of the instruments has been developed, and the function and performances such as MTF, detection sensitivity, pointing measurement accuracy etc were verified. The instrument achieved expected design objectives,  and can meet the requirements of optical autonomous navigation and scientific observation for China’s small body exploration mission.</p>

The Herschel SPIRE Fourier Transform Spectrometer Spectral Feature Finder − II. Estimating radial velocity of SPIRE spectral observation sources

ABSTRACT The Herschel SPIRE FTS Spectral Feature Finder (FF) detects significant spectral features within SPIRE spectra and employs two routines, and external references, to estimate source radial velocity. The first routine is based on the identification of rotational 12CO emission, the second cross-correlates detected features with a line template containing most of the characteristic lines in typical far infrared observations. In this paper, we outline and validate these routines, summarize the results as they pertain to the FF, and comment on how external references were incorporated.

Spectral observation of agarwood by infrared spectroscopy: The differences of infected and normal Aquilaria microcarpa

Adi DS, Hwang SW, Pramasari DA, Amin Y, Widyaningrum BA, Darmawan T, Septiana E, Dwianto W, Sugiyama J. 2020. Spectral observation of agarwood by infrared spectroscopy: The differences of infected and normal Aquilaria microcarpa. Biodiversitas 21: 2893-2899. This study was conducted to evaluate and to determine the potential spectral band assignments that influenced the differentiation of normal and infected agarwood of Aquilaria microcarpa using Fourier Transform Infrared Spectroscopy (FTIR) and Fourier Transform Near-Infrared Spectroscopy (FTNIR). The results showed that the differences in band intensity on FTIR were identified as C=O stretching (lignin), COO-stretching (hemicellulose), aromatic skeletal vibration (lignin), and C-H bending vibration. The increasing absorbances of infected agarwood were supposed as the change on the wood tissues due to the releasing resinous compound. The C-O bond (aromatic alkane) and stretching (ether), C-C stretching (aromatic alkane), and C-H bond (aromatic ring) which related to the scented fragrance of agarwood have appeared on the FTIR spectra. Multivariate analysis with principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) of the second derivative NIR spectra at the wavenumber 8,000-4,000 cm-1 showed that normal and infected agarwood was successful to be separated. Discriminant model one-on-one classification exhibited good performances as the R2 performance (R2P) values was 0.99. There were eight major wood components which contributed to the separation based on NIR spectra, where lignin, hemicellulose, and xylans were the most valuable chemical compound.