Intelligent Optical Systems Using Adaptive Optics

Until recently, the phrase adaptive optics generally conjured images of large deformable mirrors being integrated into telescopes to compensate for atmospheric turbulence. However, the development of smaller, cheaper devices has sparked interest for other aerospace and commercial applications. Variable focal length lenses, liquid crystal spatial light modulators, tunable filters, phase compensators, polarization compensation, and deformable mirrors are becoming increasingly useful for other imaging applications including guidance navigation and control (GNC), coronagraphs, foveated imaging, situational awareness, autonomous rendezvous and docking, non-mechanical zoom, phase diversity, and enhanced multi-spectral imaging. The active components presented here allow flexibility in the optical design, increasing performance. In addition, the intelligent optical systems presented offer advantages in size and weight and radiation tolerance

Advanced Optical Technologies for Space Exploration

NASA Langley Research Center is involved in the development of photonic devices and systems for space exploration missions. Photonic technologies of particular interest are those that can be utilized for in-space communication, remote sensing, guidance navigation and control, lunar descent and landing, and rendezvous and docking. NASA Langley has recently established a class-100 clean-room which serves as a Photonics Fabrication Facility for development of prototype optoelectronic devices for aerospace applications. In this paper we discuss our design, fabrication, and testing of novel active pixels, deformable mirrors, and liquid crystal spatial light modulators. Successful implementation of these intelligent optical devices and systems in space, requires careful consideration of temperature and space radiation effects in inorganic and electronic materials. Applications including high bandwidth inertial reference units, lightweight, high precision star trackers for guidance, navigation, and control, deformable mirrors, wavefront sensing, and beam steering technologies are discussed. In addition, experimental results are presented which characterize their performance in space exploration systems

Design and Performance Evaluation of Sensors and Actuators for Advanced Optical Systems

Current state-of-the-art commercial sensors and actuators do not meet many of NASA s next generation spacecraft and instrument needs. Nor do they satisfy the DoD needs for satellite missions, especially micro/nano satellite missions. In an effort to develop advanced optical devices and instruments that meet mission requirements, NASA Langley recently completed construction of a new cleanroom housing equipment capable of fabricating high performance active optic and adaptive optic technologies including deformable mirrors, reconfigurable lenses (both refractive and diffractive), spectrometers, spectro-polarimeters, tunable filters and many other active optic devices. In addition to performance, these advanced optic technologies offer advantages in speed, size, weight, power consumption, and radiation tolerance. The active optic devices described in this paper rely on birefringent liquid crystal materials to alter either the phase or the polarization of the incoming light. Design considerations and performance evaluation results for various NASA applications are presented. Applications presented will include large space telescopes, optical communications, spacecraft windows, coronagraphs, and star trackers. Keywords: Photonics, Adaptive Optics, Tunable Filters, MEMs., MOEMs, Coronagraph, Star Tracke

Design and Performance Evaluation of an Intelligent Star Tracker

Current state-of-the-art commercial star sensors typically weigh 15 pounds, attain 5 to 10 arcsecond accuracy, and use roughly 10 watts of power. Unfortunately, the current state-of-the-art commercial star sensors do not meet many of NASA’s “next-generation” spacecraft and instrument needs. Nor do they satisfy Air Force’s needs for micro/nano-satellite systems. In an effort to satisfy micro/nano satellite mission needs the Air Force Research Laboratory is developing an intelligent star Tracker, called IntelliStar, which incorporates several novel technologies including Silicon carbide optical housing, MEMs based adaptive optic technologies, smart active pixels, and algebraic coding theory. The design considerations associated with the development of the IntelliStar system are presented along with experimental results which characterize each technologies contribution to overall system performance. In addition to being light weight, the IntelliStar System offers advantages in speed, size, power consumption, and radiation tolerance

Stature Estimates of the Classic Period Maya from Chac Balam and San Juan, Ambergris Caye, Belize

This thesis presents updated sex and stature estimates for ancient Maya females and males who lived in San Juan and Chac Balam in northern Ambergris Caye from approximately AD 700-900. The regression formulae used in this study reflect a closer population affinity to the Maya compared to the equations used in the original analysis by Glassman (1995). Del Angel and Cisneros’ (2004) formulae were used when estimating stature based on a complete long bone. In Steele and Bramblett (1988), Steele and McKern (1969) and Steele (1970) regression formulae were used when estimating stature based on an incomplete humerus, femur, or tibia. Population specific stature formulae (del Angel and Cisneros 2004) were compared to nonspecific stature population formulae (Trotter 1970; Steele and Bramblett 1988). Bass (1995) cited Stewart (1979) for sex estimates based on the maximum diameter of the humeral and femoral heads; Frutos (2005) and Miller Wolf (personal communication) also provided metrics for the maximum humeral head diameter. The results from this study show statistically significant shorter stature for these individuals than initially estimated by Glassman (1995), but similar sex estimations. These updated analyses can provide further insight into the daily lives and overall health of the ancient Maya from Ambergris Caye. Conclusions drawn from this research include how different, population specific, regression formulae create a significant difference in the stature estimation for individuals from San Juan and Chac Balam during the Classic Period. Also, it is possible for stature to be estimated using regression analyses for fragmented long bones, although it is not always as accurate as using a complete bone measurement. Population specific metrics for the humeral and femoral heads can alter the results of sex estimation as well. Accurate stature formulae are an important foundation for estimating stature and understanding the health of modern and past populations

Physical Activity in Secondary School Pupils: Headline Indicators 2014

In 2013, GoWell East commenced a cohort study of physical activity among secondary school pupils in Glasgow. The study will run from 2013 to 2017, following a group of pupils in six Glasgow secondary schools throughout their school careers from S1 to S5. The study tracks pupils’ participation in physical activity, including sports, as well as other types of activity (including travel to and from school), during their school time and leisure time, during the week and at the weekend. The research is done by asking pupils to complete the Youth Physical Activity Questionnaire (YPAQ)1 .   A group of S5 pupils were also asked to complete the survey in 2013 in order to provide a benchmark with which to compare the S1 study cohort when they reach S5 in 2017

“Melq'ilwiye” Coming Together: Reflections on the journey towards Indigenous social work field education

This article shares the reflections, based on exploratory research and practice in the Interior of British Columbia (BC), Canada, of social work and human service field education coordinators on reconciling field education programs. Drawn from a larger study, the authors present the findings from in-depth interviews, using an Indigenous intersectional storytelling approach to understand the experiences of Indigenous and non-Indigenous field coordinators in moving towards an Indigenous field education model. There is limited research on Indigenous field education and few publications on the experiences of field education coordinators about this important area of practice. This article draws from the study's previous publications and focuses specifically on the narratives of field education coordinators in order to contribute to the development of new literature on the process of reconciling field education practices. The findings of the study call for a transformation of field education policies and practices in order to support Indigenous intersectional and culturally safe field education

Polarization Compensation of Fresnel Aberrations in Telescopes

Large aperture space telescopes are built with low F# s to accommodate the mechanical constraints of launch vehicles and to reduce resonance frequencies of the on-orbit system. Inherent with these low F# s is Fresnel polarization which affects image quality. We present the design and modeling of a nano-structure consisting of birefringent layers to control polarization and increase contrast. Analysis shows a device that functions across a 400nm bandwidth tunable from 300nm to 1200nm. This Fresnel compensator device has a cross leakage of less than 0.001 retardance

Delivery of patient education and support using an online digital platform for patients undergoing primary hip and knee replacement: The patient’s perspectives

The aim of the present evaluation was to evaluate the use of an online digital platform (ODP) to deliver patient education and support (PES) to patients undergoing total hip replacement (THR) and total knee replacement (TKR) surgery. Six objectives were outlined to assess the following areas: patient engagement; ease of use; understanding of information; quantity of information; aid of recovery; suggestions for improvements. A qualitative service evaluation of the ODP. Participants included patients who were registered to the platform for THR or TKR, were at least 90 days post-surgery and had accessed at least one carepac. Interviews followed a semi-structured schedule and were transcribed and analysed using thematic analysis. A total of 14 participants were interviewed. Three main themes were identified, each with subsequent sub-themes. (1) Health behaviours – internal control of own health, external email prompts, social support. (2) Contribution to recovery – quantity and quality of information available, structured program, suggestions of improvements to better aid recovery. (3) PES delivery – ease of use and accessibility of an ODP, technology advancements, alternative methods of PES. The online PES platform was beneficial for patients undergoing THR and TKR surgery. It aided their understanding of and preparedness for joint replacement surgery, as well as being a supportive tool for rehabilitation and recovery. All patients actively engaged with the ODP and in doing so, developed a greater understanding as a result of the detailed and structured carepacs assigned. Experience Framework This article is associated with the Patient, Family & Community Engagement lens of The Beryl Institute Experience Framework (https://www.theberylinstitute.org/ExperienceFramework). Access other PXJ articles related to this lens. Access other resources related to this lens

Intelligent Star Tracker

We describe our Intelligent Star Tracker System. Our Intelligent Star Tracker System incorporates an adaptive optic catadioptric telescope in a silicon carbide housing. Leveraging off of our active optic technologies, the novel active pixel position sensors (APPS) enable wide dynamic range and allows simultaneous imagery of faint and bright stars in a single image. Moreover, the APPS, in conjunction with the adaptive optics technologies, offer unprecedented accuracy in altitude and navigation applications