|Blue Line's differential sensing systems and actuator designs have been employed in a wide variety of aerospace and research projects. Several of our past projects are described below.
Hobby-Eberly Space Telescope
Blue Line Engineering is currently engaged in a joint project with NASA's Marshall Space Flight Center to design, build, and install the Segment Alignment Maintenance System (SAMS) for the Hobby-Eberly Telescope (HET) at the McDonald Observatory outside Fort Davix, TX. Blue Line is solely responsible for all critical sensing and data acquisition elements of HET's SAMS. This joint venture with NASA is a direct result of Blue Line's technical expertise in the area of active figure maintenance of segmented mirror telescopes. Click here to view more information on the HET project and to see photos of the telescope.
Fully Active Segmented Telescope (FAST)
Under a two-phase NASA SBIR grant, Blue Line designed and produced an optically correct 1/8 scale replica of the planned 8-meter Next Generation Space Telescope (NGST), also known as the James Webb Space Telescope. In Phase I, Blue Line developed a design for a segmented 1-meter astronomical telescope with fully active figure control. The design incorporated hinged mirror petals and a deployable secondary mirror, both features of the planned NGST, and utilized Blue Line's Shear Sensing technology to align and correct mirror segment positions. Phase II funded construction of a working telescope employing Blue Line's FAST design. The telescope, which is currently in production, will serve as a testbed for adaptable active telescope structures and dynamics. The telescope will be compatible with commercial off-the-shelf software, allowing implementation of a variety of control algorithms. Blue Line's FAST technology may lead to the development of an entirely new class of fixed-site and field-portable research tools for observational astronomy, which would be of great interest to researchers, government agencies, aerospace contractors, and others. A PowerPoint presentation on this project is also available, as well as a QuickTime demonstration showing how FAST technology could be applied in advanced space telescope operations.
AI-Based Self-Correcting, Self-Reporting Edge Sensors
In 2000, Blue Line began assessing the feasibility of a new class of super-enhanced edge sensors for segmented mirror telescopes. Edge sensors may be used to deploy, align, and phase-match the primary mirror segments of space-based instruments such as the Next Generation Space Telescope. Through our research, we have developed edge sensors that are suitable for operational environments ranging from moderately hot (373ºK) to cryogenic (well below 30ºK). In developing the technology, fuzzy logic was used to provide health and status monitoring and to equip each sensor with a self-reporting capability. Artificial neural networks were employed to provide self-correcting and self-tuning capabilities. New error methods were devised for superb accuracy, including multi-mode measurement of both phasing errors and gap separation between neighboring segments. The results of this research are also directly applicable to a broad range of sensors and actuators other than edge sensors. It is expected that the same hardware and software may be applied to industrial sensors and controls for greatly enhanced performance and reliablility in factory automation.
Levitated Segmented Mirror Array
In 1999, Blue Line conducted research to establish the feasibility of a radically different approach to construction of high-precision large aperture mirrors in space. The concept was based on a deployable phased array mirror system that would meet or exceed the most demanding requirements for NASA's Next Generation Space Telescope. The most remarkable aspect of this innovative approach is that the entire mirror array is held captive in a controlled grid of local magnetic fields such that the segmented primary mirror is virtually free-floating, and thus free from mechanical and thermal distortions. Under this project, we developed the necessary actuators, edge sensors, and control methodologies to demonstrate the ability to phase-match a magnetically levitated array in an Earth-based laboratory environment. The research demonstrated the high degree of mechanical and thermal isolation between reaction structure and segmented mirror array, introducing extremely low-mass mirror substrates for a variety of applications.
Superconducting Non-contact Actuators
A two-phase NASA SBIR grant was awarded to Blue Line in 1996 to fund the design and development of a new class of non-contact actuators, which employ high-temperature superconducting (HTSC) materials to control the position of small, low-mass objects such as mirror segments. HTSC materials are bonded to the back surface of a low-mass object, and the object and HTSC materials are cooled to cryogenic temperatures. When electromagnetic flux fields are applied to the diamagnetic superconducting material, the material is repelled and the object is levitated. By varying the magnitude of the current flowing though the electromagnet, the amount of force exerted on the levitated object can be controlled. This technology creates a new approach to control of active optic elements at extremely cold temperatures (below 40¡K). Phase I produced design analyses, parametric trade studies, laboratory testing, and fabrication of a proof-of-concept demonstrator. In Phase II, actuators were built and characterized, then fitted to a low-mass mirror segment to demonstrate levitated tip, tilt, and piston control. Novel actuator drive electronics and self-sensing closed-loop controls were also employed. The research culminated in the delivery of a testbed to MSFC for precision pointing and control of two mirrors in a cryogenic chamber. The actuators provide an answer to the current lack of simple, moderately priced magnetic levitation platforms in the commercial marketplace. This innovation can also provide a very high degree of thermal and mechanical isolation in industrial applications where the need for cryogenic cooling is not a limitation.
Active Segmented Mirror Technology Development
In 1994, Blue Line received a Phase I NASA Small Business Innovation Research (SBIR) grant to design and develop precision active mirror segments for use in astronomy and laboratory research in adaptive optics. The segments developed by Blue Line were intended to serve as building blocks for continuous mirror surfaces, enabling low-cost construction of very large adaptive mirrors in astronomical telescopes. Phase I research resulted in a number of significant accomplishments:
Phase II of the project refined the designs and techniques developed in Phase I, reflecting input from the NASA review committee, and moved the application from concept to practice in the form of a small cluster of prototype active mirror segments. Calibration and initial testing were performed before the hardware was transferred to NASA for full characterization and performance assessment.
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