Tradespace Investigation of a Telescope Architecture for Next-generation Space Astronomy and Exploration

Humanity’s endeavor to further its scientific understanding of the celestial heavens has led to the creation and evolution of increasingly powerful and complex space telescopes. Space telescopes provide a view of the solar system, galaxy, and universe unobstructed by Earth’s atmosphere and have profoundly changed the way people view space. In an effort to further advance space telescope capability and achieve the accompanying scientific understanding, the Massachusetts Institute of Technology (MIT), specifically, course 16.89 Space Systems Engineering, explored the tradespace of architectural enumerations encompassed within the design of an ultraviolet-optical-infrared (UVOIR) space telescope located at Sun-Earth Lagrangian Point Two (SE-L2). SE-L2 presents several advantages as an operating location for a UVOIR telescope such as a thermally stable environment and an orbit that allows the telescope to maintain a constant orientation with respect to all of the primary sources of heat and light. The main disadvantages associated with SE-L2 are caused by its relatively large distance from Earth, which marginalizes the effectiveness of real-time telerobotics because of latency and increases the cost of communications, launch, and servicing. Course 16.89 believes that, for this UVOIR application, the strengths of this operating location outweigh its weaknesses and therefore decided to explore the family of opportunities associated with SE-L2. This course used appropriate performance and system metrics to quantify the effectiveness of the aforementioned architectures and create a Pareto front of viable architectures. Evaluating the designs along the Pareto front allowed the course to characterize and group architectures and present these group-types to stakeholders for the selection of an optimal space telescope according to stakeholder requirements and resources. This course also developed sensitivity analysis, which allowed for a greater understanding of how architectural decisions affect the performance of the satellite. Segmentation, modularity, assembly, autonomy, and servicing were key aspects of this multidimensional analysis given the 16.8-meter class size and location of the telescope. Within the respective operating environment and for a spacecraft of similar characteristics, this model will allow stakeholders to predict the long-term operational effectiveness of different space telescope architectures and capture the synergistic effects of combining various architectural decisions into a spacecraft design. The following sections step through the aforesaid analysis and design efforts conducted in 16.89 beginning with Section III, which explicitly performs the stakeholder analysis and articulates the requirements of the mission. Section IV gives an overview of past designs and expands upon the architecture enumerations pertinent to this project, while Section V presents the methods and metrics by which those architectures will be evaluated and the system metrics which will be balanced and optimized in the creation of this space telescope. Section VI will present the model validation of this project and Section VII will discuss the results and analyses of the project. Finally, Section VIII will explore the future work opportunities of this project, while Section IX will present the conclusions and recommendations drawn from this project.MIT Department of Aeronautics and Astronautic

Effect of control interface implementation on operation of a multi degree of freedom telerobotic arm

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2017.Cataloged from PDF version of thesis.Includes bibliographical references (pages 109-115).In exploration, scenarios can include a human working along-side - or attached to - a robot. For example, concepts of Mars human-robot exploration teams, or extravehicular activity (EVA) on the International Space Station (ISS) with an astronaut fixed to the end of a large robot arm for stability. Robots in these scenarios must be able to be directed in real time to react to environmental unknowns. In this work, use of a fully-wearable gesture system was proposed to provide control of the robot to the human in the field. A wearable gesture interface would allow user mobility in the field, would allow the user full arm range of motion when not in use, and could be built into the user's clothing to avoid requiring them to carry additional equipment for robot control. This work used the Canadarm2 as a case study for exploring implementations and input mappings for robot operations with a gesture interface in complex environments. Manual control of the Canadarm2 is difficult, involving a complex twin-joystick interface. Although astronauts on EVA often stand fixed at the end of the robot arm for stability, EVA astronauts cannot control the arm themselves, instead relying on teleoperation by a second astronaut inside the ISS. A study was conducted with a simulated Canadarm2, comparing three different gesture implementations to the traditional joystick input method. In order to test gesture control mappings of this case, a gesture interface was needed for operation. The wearable gesture system selected used integrated surface electromyography sensors and inertial measurement units to detect arm and hand gestures.Two gesture mappings permitted multiple simultaneous inputs (multi-input), while the third was a single input method. One multi-input method was inspired and aligned with natural human reach while the other divided controls between different segments of the human arm kinematic chain. The single input method exhibited high workload in addition to reduced efficiency as compared to the joystick control group. The gesture mapping inspired by human motor control showed potential for performance equivalent to traditional joystick controls after training. The multi-input mapping less aligned with natural motor control showed reduced completion rate for certain tasks and higher overall workload as compared to the joystick interface. Unlike the joystick controls, the gesture interface was limited to one rotational input at a time. To investigate potential performance effects due to such limits on controller degrees of freedom (DOF), a second study was conducted that locked different DOF in the joystick interface. Four joystick interfaces were compared: full multi-axis (with nominal six DOF), rotation limited (one rotation at a time), translation limited (one translation at a time), and without simultaneous translation/rotation or "non-bimanual." This study found no statistically significant differences in performance or workload between traditional controls and reduced rotational DOF, which was comparable to the gesture interface mapping. For the non-bimanual condition, there was an increase in task time combined with decreased multi-rotation, highlighting that non-bimanual operation may have potential in training for rotation efficiency. Two different strategies were observed during translation limiting to overcome inability to visually track, align with, and move toward the target simultaneously. This work highlights the importance of multi-input control for complex robotic teleoperation and provides recommendations for the development of input mappings and implementations of gesture control interfaces, as well as any interfaces that require reduced DOF as compared to the operational environment or system being controlled.by Sherrie Alyssa Hall.Ph. D

Boeing Interns Panel

Panel discussion presented on September 13, 2011 from 06:00pm - 07:30pm in Student Success Center, Press Room A and B on the Georgia Tech campus.Runtime:43:40 minute