An electronic control unit has been fabricated and tested that can be replicated as a universal interface between the electronic infrastructure of a spacecraft and a brushless-motor (or other electromechanical actuator) driven mechanism that performs a specific mechanical function within the overall spacecraft system. The unit includes interfaces to a variety of spacecraft sensors, power outputs, and has selectable actuator control parameters making the assembly a mechanism controller. Several control topologies are selectable and reconfigurable at any time. This allows the same actuator to perform different functions during the mission life of the spacecraft. The unit includes complementary metal oxide/semiconductor electronic components on a circuit board of a type called “rigid flex” (signifying flexible printed wiring along with a rigid substrate). The rigid flex board is folded to make the unit fit into a housing on the back of a motor. The assembly has redundant critical interfaces, allowing the controller to perform time-critical operations when no human interface with the hardware is possible. The controller is designed to function over a wide temperature range without the need for thermal control, including withstanding significant thermal cycling, making it usable in nearly all environments that spacecraft or landers will endure. A prototype has withstood 1,500 thermal cycles between –120 and +85 °C without significant deterioration of its packaging or electronic function. Because there is no need for thermal control and the unit is addressed through a serial bus interface, the cabling and other system hardware are substantially reduced in quantity and complexity, with corresponding reductions in overall spacecraft mass and cost.
This work was done by Greg Levanas, Thomas McCarthy, Don Hunter, Christine Buchanan, Michael Johnson, Raymond Cozy, Albert Morgan, and Hung Tran of Caltech for NASA’s Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Electronics/Computers category.
In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:
Innovative Technology Assets Management
JPL
Mail Stop 202-233
4800 Oak Grove Drive
Pasadena, CA 91109-8099
(818) 354-2240
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Refer to NPO-41776, volume and number of this NASA Tech Briefs issue, and the page number.
This Brief includes a Technical Support Package (TSP).
Universal Controller for Spacecraft Mechanisms
(reference NPO-41776) is currently available for download from the TSP library.
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Overview
The document is a Technical Support Package from NASA's Jet Propulsion Laboratory, focusing on the development of a Universal Controller for Spacecraft Mechanisms, specifically designed for use in Martian environments. It outlines the objectives, features, and technological advancements related to spacecraft actuators, which are critical components for the operation of various mechanisms in space missions.
One of the primary goals of the actuator development effort is to create flight actuators that can survive and function effectively in the extreme conditions of Mars, where surface temperatures can range from -130°C to +20°C. The document emphasizes the need for these actuators to operate without thermal control, which is a significant challenge given the harsh Martian climate. Additionally, the aim is to extend the mechanical life of these actuators by more than a factor of 20 compared to current capabilities, thereby enhancing the longevity and reliability of missions.
Key features of the actuators include a long operational life of at least two years, with a roving range capability of up to 100 kilometers. The design considerations focus on reducing system interfaces to minimize signal cabling and achieving mass reduction through miniaturization. This is crucial for space missions where weight is a critical factor.
The document also details the actuator capabilities, which include a stall current range from 100 milliamps to 15 amps, and the use of various motor types such as brushless DC, synchronous, and stepper motors. The actuators are designed to accommodate most types of feedback sensor inputs, enhancing their versatility and functionality.
Furthermore, the document provides insights into the integrated motor and drive electronics, highlighting the various wires and interfaces necessary for communication and power supply within the actuator system.
Overall, this Technical Support Package serves as a comprehensive overview of the advancements in actuator technology aimed at improving the performance and reliability of spacecraft mechanisms for future Mars missions. It reflects NASA's commitment to innovation in aerospace technology and the pursuit of long-term exploration goals.
