The Area Defense Anti-Munitions (ADAM) is a low cost and effective high power laser weapon system. It’s designed to address and negate important threats such as short-range rockets, UAVs, and small boats. Many critical optical components operate in the system. The optics and mounts must accommodate thermal and mechanical stresses, plus maintain an exceptional wave front during operation. Lockheed Martin Space Systems Company (LMSSC) developed, designed, and currently operates ADAM. This paper covers the design and development of a key monolithic, flexured, titanium mirror mount that was manufactured by CalRAM using additive processes.
The optics train of the Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST)
includes a pick-off mirror (POM) mounted in the focus and alignment mechanism (FAM). Over the course of the
mission, the POM will have a narrow view of the L2 space environment. Charged particles will impinge and collect on
the mirror surface increasing the possibility of arcing to the adjacent baffle. A technique to ground the POM and remove
accumulated charge has been qualified and implemented on the flight instrument. This paper will provide an overview of
the qualification process including cryogenic resistance measurements, vibration testing and optical surface error
measurements. To measure the efficiency of this grounding technique, a POM engineering model was exposed to
representative mission electron fluence and results with the POM grounded and ungrounded will be presented.
The Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST) has an optical prescription which terminates at two focal plane arrays for each module. The instrument will operate at 37K after experiencing launch loads at 293K. The focal plane array housings (FPAHs), including stray light baffles (SLBs) must accommodate all associated thermal and mechanical stresses. In addition, the stray light baffles must be installed in situ on the previously assembled flight modules. The main purpose of the FPAH SLBs is to effectively attenuate mission limiting stray light on the focal planes. This paper will provide an overview of the NIRCam stray light baffle design, mechanical and optical analysis, hardware implementation and test results.
The Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST) has an optical
prescription which includes numerous fold mirror assemblies. The instrument will operate at 35K after experiencing
launch loads at ~293K. The optic mounts must accommodate all associated thermal and mechanical stresses, plus
maintain exceptional optical quality during operation. Lockheed Martin Space Systems Company (LMSSC) conceived,
designed, analyzed, assembled, tested, and integrated the mirror assemblies for the NIRCam instrument. This paper
covers the design, analysis, assembly, and test of two of the instruments key fold mirrors.
The Pick Off Mirror (POM) is the business end of the Focus and Alignment Mechanism (FAM) of NIRCam. The POM
harnesses the light delivered by the telescope and steers it into the Near Infrared Camera. At strategic points during the
build and test of the Pick Off Mirror and its mechanism (the FAM) the surface figure error (SFE) of the mirror was
monitored. This metric was used to track the health of the mirror throughout this testing regime. For example, the team
ran an SFE test before and after Vibration testing the FAM. In this paper, we will provide an overview of the testing
regime and the results of these periodic SFE tests. These results lead to the qualification of the POM and FAM designs
for flight on the James Webb Space Telescope.
The Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST) includes numerous
optical assemblies. The instrument will operate at 35K after experiencing launch loads at ~293K and the optic mounts
must accommodate all associated thermal and mechanical stresses, plus maintain exceptional optical quality during
operation. Lockheed Martin Space Systems Company (LMSSC) conceived, designed, analyzed, assembled, tested, and
integrated the optical assemblies for the NIRCam instrument. With using examples from NIRCam, this paper covers
techniques for mounting small mirrors and lenses for cryogenic space missions.
The Focus and Alignment Mechanism (FAM) is an opto-mechanical, cryogenic mechanism that positions the Pick-Off
Mirror (POM) for the Near Infrared Camera of the James Webb Space Telescope. The POM is used to direct the light
collected by the telescope into the Near Infrared Camera. The POM is a spherical, fused silica mirror. In order to retain
high surface quality at cryogenic temperatures, the POM is attached to the mechanism via a titanium flexure-mount
assembly. Three linear actuators are employed to position the POM in tip, tilt and piston. These linear actuators are
stepper motor driven, with harmonic drive gear reduction. In this paper, we will summarize the design and role of this
opto-mechanical mechanism and present the results of the environmental testing of the Engineering Test Unit. The tests
performed were thermal-vacuum cryogenic cycling, and vibration testing.
KEYWORDS: Titanium, Interfaces, Optical fabrication, Composites, Manufacturing, Finite element methods, James Webb Space Telescope, Aerospace engineering, Design for manufacturability, Epoxies
Two optical modules, mounted back to back, comprise JWSTs NIRCam (Near Infrared Camera) instrument. Each
module contains a short wavelength (SW) and long wavelength (LW) path. The instrument will be mounted to the ISIM
(Integrated Science Instrument Module) of the spacecraft via a mechanical support structure. Within a fourteen month
timeframe this aerospace structure was conceived, designed, analyzed, manufactured, integrated, tested and qualified for
flight. This paper describes the technical product and its fast, affordable, and successful evolution from concept design
to flight qualification, including critical decision points and lessons learned.
The pupil imaging lens (PIL) assembly is one component within the NIRCam instrument, which is the primary imaging
instrument on the James Webb Space Telescope (JWST). The main purpose of the PIL assembly is to form an image of
the eighteen primary mirror segments of the JWST onto the NIRCam focal plane arrays (FPAs). NIRCam is the only
instrument on the JWST observatory with wave front sensing (WFS) capability, and will use the PIL in conjunction with
the WFS measurements1.
The purpose of this paper is to introduce the audience to a monolithic PIL assembly created from five unique lenses
mounted to an optical baseplate. The lenses are assembled using a direct bonding method, with the aid of a diluted
potassium hydroxide solution. Described in this paper is a simple, yet precise method for aligning and assembling the
PIL optics.
This paper describes the design of the compact, lightweight, and athermalized Pick Off Mirror and Mount. Structural and thermal analysis as well as actual prototype testing are also described.
This paper describes the design of the compact, lightweight, and athermalized Pick Off Mirror and Mount as well as similar mounts for other NIRCam fold mirrors, including the Focal Plane Assembly Fold Mirror Mount. Structural and thermal analysis as well as actual prototype testing is also described.
A sensitivity evaluation of mounting 100mm optics using elastomer or bipod flexures was completed to determine the relative effects of geometry, structure, material, thermal and vibration environment as they relate to optical distortion. Detailed analysis was conducted using various finite element-modeling methods. Parts were built and the results were verified by conducting brassboard tests.
What makes this evaluation noteworthy is the two vastly different approaches, and how they both exhibited athermal properties and minimized optical distortion. Materials were carefully selected while the geometry and structure were optimized through analytical iteration.
The elastomeric optical mount consists of 12 equally spaced pads of RTV placed around the circumference of the optic. These pads were sized to maximize stiffness and minimize surface deformations. The surrounding material was appropriately selected in order to contribute to an athermal design.
The bipod flexure optical mount uses three flexures cut from a single piece of material. Each flexure is a bipod oriented to comply radially with changes in temperature. This design is monolithic and uses conventional epoxy at the optical interface. The result is a very stiff athermal design.
This paper covers both opto-mechanical designs, as well as analytical results from computer modeling and brassboard tests.
Optical systems, which operate over a wide range of Fresnel numbers, are often times performance-limited by diffraction effects. In order to characterize such effects at the 40-100 picometer level, a diffraction testbed has been built which has the capability of measuring diffraction effects at this level. Concurrently, mathematical diffraction modeling tools have been developed that propagate an input wavefront through an optical train, while retaining amplitude and phase information at a grid resolution sufficient for yielding picometer-resolution diffraction test data. This paper contains a description of this diffraction hardware testbed, the diffraction modeling approach, and a comparison of the modeled and hardware test results, which then serves as validation of the diffraction modeling methodology.
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