Conducting high resolution field microscopy with coupled laser spectroscopy that can be used to selectively analyze the
surface chemistry of individual pixels in a scene is an enabling capability for next generation robotic and manned
spaceflight missions, civil, and military applications. In the laboratory, we use a range of imaging and surface
preparation tools that provide us with in-focus images, context imaging for identifying features that we want to
investigate at high magnification, and surface-optical coupling that allows us to apply optical spectroscopic analysis
techniques for analyzing surface chemistry particularly at high magnifications. The camera, handlens, and microscope
probe with scannable laser spectroscopy (CHAMP-SLS) is an imaging/spectroscopy instrument capable of imaging
continuously from infinity down to high resolution microscopy (resolution of ~1 micron/pixel in a final camera format),
the closer CHAMP-SLS is placed to a feature, the higher the resultant magnification. At hand lens to microscopic
magnifications, the imaged scene can be selectively interrogated with point spectroscopic techniques such as Raman
spectroscopy, microscopic Laser Induced Breakdown Spectroscopy
(micro-LIBS), laser ablation mass-spectrometry,
Fluorescence spectroscopy, and/or Reflectance spectroscopy. This paper summarizes the optical design, development,
and testing of the CHAMP-SLS optics.
Very high contrast imagery, required for exoplanet image acquisition, imposes significantly different criteria upon telescope architecture than do the requirements imposed upon most spaceborne telescopes. For the Eclipse Mission, the fundamental figure-of-merit is a stellar contrast, or brightness reduction ratio, reaching a factor of 10-9 or better at star-planet distances as close as the 4th Airy ring. Factors necessary to achieve such contrast ratios are both irrelevant and largely ignored in contemporary telescope design. Although contemporary telescoeps now meet Hubble Space Telescope performance at substantially lower mass and cost than HST, control of mid-spatial-frequency (MSF) errors, crucial to coronagraphy, has not been emphasized. Accordingly, roughness at MSF has advanced little since HST. Fortunately, HST primary mirror smoothness would nearly satisfy Eclipse requirements, although other aspects of HST are undesirable for stellar coronagraphy. Conversely, the narrow field required for Eclipse eases other drivers of traditional telescope design. A systematic approach to telescope definition, with primary and sub-tier figures-of-merit, will be discussed in the context of the Eclipse Mission.
The multi-angle imaging spectro-radiometer (MISR) instrument, which is scheduled to fly on the EOS AM1 platform, contains nine refractive cameras (four different lens designs) at preselected view angles which image in the push broom mode. Each focal plane contains four charge coupled device (CCD) line arrays consisting of 1504 active pixels; each array is preceded by one of the MISR spectral filters. In order to facilitate registration of the data generated by the 36 arrays during the initial phase of the mission, the crosstrack pointing angle of each pixel in each array was measured in the laboratory at the camera subsystem level. These measurements were particularly challenging because the pixels had to be calibrated under flight conditions (in a vacuum over the temperature range 0 to 10 degrees Celsius) to an accuracy of 1/8 pixel or 2.6 micrometer. Given the first order properties of the various lenses, this requirement implies that the distortion had to be calibrated to better than 10 arcsec. This paper will discusses the hardware and software techniques utilized to accomplish this stringent calibration.
A unique, highly automated thermal-vacuum facility for optical testing of lenses and cameras is described. In particular, measurements of MTF, boresight, and geometric image distortion over a large parameter space including wavelength, field of view and temperature will be discussed. Unique aspects of the facility include a 'virtual nodal bench' opto-mechanical metrology system and fiber-optic illumination of mechanical reference features.
Patricia Beauchamp, Robert Benoit, Robert Brown, Carl Bruce, Gun-Shing Chen, Michael Chrisp, J. Davidson, George Fraschetti, Stanley Petrick, David Rodgers, Bill Sandel, Cesar Sepulveda, Laurence Soderblom, Dexter Wang, Stanley Soll, Roger Yelle
The planetary integrated camera-spectrometer, PICS, is a highly integrated sensor system which performs the functions of three optical instruments: a near infrared (IR) spectrometer, a visible imaging camera, and an ultraviolet (UV) spectrometer. Integration serves to minimize the mass and power required to operate a complex suite of instruments, and automatically yields a comprehensive data set, optimized for correlative analysis. This approach is useful for deep space missions such as Pluto Express and will also enable Galileo/Cassini class remote observations of any object within the solar system. In our baseline concept, a single set of lightweight multiwavelength foreoptics is shared by a UV imaging spectrometer (80 spectral channels 70 - 150 nm), a two-CCD visible imaging system (shuttered in two colors 300 - 500 nm and 500 - 1000 nm), and a near-IR imaging spectrometer (256 spectral channels 1300-2600 nm). The entire structure, including its optics, is built from silicon carbide (SiC) for thermal and dimensional stability. In addition, there are no moving parts and each spectrometer covers a single octave in wavelength. A separate port is provided for measurement of a UV solar occultation and for spectral radiance calibration of the IR and visible subsystems. The integrated science that the PICS will yield meets or exceeds all of the Priority-1A science objectives, and many Priority 1-B science objectives as well, for the Pluto Express Mission. This paper provides details of the PICs instrument design, fabrication and testing, both at the sub-assembly and the instrument level. In all tests, including optical, thermal vacuum, and structural/dynamics, the PICS hardware prototype met or exceeded functional requirements.
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