Michael A. Johnson

A Review of NASA's Radiation-Hardened Electronics for Space Environments Project

NASAs Radiation Hardened Electronics for Space Exploration (RHESE) project develops the advanced technologies required to produce radiation hardened electronics, processors, and devices in support of the requirements of NASAs Constellation program. Over the past year, multiple advancements have been made within each of the RHESE technology development tasks that will facilitate the success of the Constellation program elements. This paper provides a brief review of these advancements, discusses their application to Constellation projects, and addresses the plans for the coming year.

Developments in Radiation-Hardened Electronics Applicable to the Vision for Space Exploration

The Radiation Hardened Electronics for Space Exploration (RHESE) project develops the advanced technologies required to produce radiation hardened electronics, processors, and devices in support of the anticipated requirements of NASAs Constellation program. Methods of protecting and hardening electronics against the encountered space environment are discussed. Critical stages of a spaceflight mission that are vulnerable to radiation-induced interruptions or failures are identified. Solutions to mitigating the risk of radiation events are proposed through the infusion of RHESE technology products and deliverables into the Constellation programs spacecraft designs.

High‐Performance, Radiation‐Hardened Electronics for Space and Lunar Environments

The Radiation Hardened Electronics for Space Environments (RHESE) project develops advanced technologies needed for high performance electronic devices that will be capable of operating within the demanding radiation and thermal extremes of the space, lunar, and Martian environment. The technologies developed under this project enhance and enable avionics within multiple mission elements of NASAs Vision for Space Exploration, including the Constellation programs Orion Crew Exploration Vehicle, the Lunar Lander project, Lunar Outpost elements, and Extra Vehicular Activity (EVA) elements. This paper provides an overview of the RHESE project and its multiple task tasks, their technical approaches, and their targeted benefits as applied to NASA missions.

Advanced Avionics and Processor Systems for Space and Lunar Exploration

NASAs newly named Advanced Avionics and Processor Systems (AAPS) project, formerly known as the Radiation Hardened Electronics for Space Environments (RHESE) project, endeavors to mature and develop the avionic and processor technologies required to fulfill NASAs goals for future space and lunar exploration. Over the past year, multiple advancements have been made within each of the individual AAPS technology development tasks that will facilitate the success of the Constellation program elements. This paper provides a brief review of the projects recent technology advancements, discusses their application to Constellation projects, and addresses the projects plans for the coming year.

Low temperature thermal cycle survivability and reliability study for brushless motor drive electronics

This paper presents a survivability and reliability investigation for integrated actuator and brushless motor drive electronics packaging and components under an extreme low temperature and high thermal cycle environment. A universal brushless motor drive electronics assembly has been designed, built, and thermal cycle tested for use in Mars, Moon, and asteroid type cold environments without the need for any active thermal control. The assembly uses electronic part types and chip-on-board electronic packaging technology that allow operation at temperatures down to -180degC. The thermal cycle capability of the assembly has been demonstrated to be in excess of 2010 cycles from -120degC to 85degC, over a 210degC total temperature swing. Future space missions will require electronic and actuator systems on a planet, asteroid or Moon surface to function beyond the established reliability limits of currently used components and materials systems. In support of this target application, the Jet Propulsion Laboratory (JPL) has performed a series of experiments to test the reliability of actuators, sensors, electronic components, and electronic packaging designs to provide input to the detailed flight design of a universal brushless motor drive electronics and integrated actuator assembly. These experiments started with the use of a chip-on-board electronic packaging strategy due to its inherent advantage of improved high functionality with minimal circuit board area compared with standard packaged electronic components. Initial electronic packaging experiments were comprised of various sized chip devices with gold wire bonds. The second phase of electronic packaging experiments conducted at JPL consisted of power devices with large diameter wire bonds as well as various surface mount resistor devices. Full factorial experiments were designed to find the most reliable combinations of substrate type, component attach method and encapsulation. The surviving material combinations after a minimum of 1500 thermal cycles were utilized to form the basis of the packaging and electronic component detailed design approach used in the universal brushless motor drive electronics design. Electrical failures were defined as open circuits. A failure analysis procedure was applied by defining the failure mechanism and applying a risk mitigation. After 1500 cycles, the packaged assembles were cycled to exceed 2010 cycles and additional material considerations were made. In addition, selected components were functionally tested over the temperature range of +100degC to -180degC and cold soaked at -150degC for 1000 hours for reliability. A design for reliability method was also developed at the component and circuit level for electronics operating at extreme low temperatures

Using model-based reasoning for autonomous instrument operation

Model-based reasoning has been applied as an autonomous control strategy on the Low Energy Neutral Atom (LENA) instrument currently flying onboard the Imager for Magnetosphere-to-Aurora Global Exploration (IMAFE) spacecraft. Explicit models of instrument subsystem responses have been constructed and are used to dynamically adapt the instrument to the spacecrafts environment. These functions are cast as part of a virtual Principal Investigator (VPI) that autonomously monitors and controls the instrument. In the VPIs current implementation, LENAs command uplink volume has been decreased significantly from its previous volume; typically, no uplinks are required for operations. This work demonstrates that a model-based approach can be used to enhance science instrument effectiveness. The components of LENA are common in space science instrumentation, and lessons learned by modeling this system may be applied to other instruments. Future work involves the extension of these methods to cover more aspects of LENA operation and the generalization to other space science instrumentation.

Advanced Avionics and Processor Systems for a Flexible Space Exploration Architecture

The Advanced Avionics and Processor Systems (AAPS) technology development project was established to foster and mature the avionic and processor technologies required to fulfill NASAs goals for future space and lunar exploration. Over the past year, multiple advancements have been made within each of the individual AAPS technology development tasks. This paper provides a brief review of the projects accomplishments over the past fiscal year, discusses the applicability of these accomplishments to the Constellation program and to future NASA exploration missions, and addresses the projects termination and re- establishment within the new Exploration Technology Development and Demonstration program.

Virtual Engineering and Science Team - Reusable autonomy for spacecraft subsystems

Addresses the design, development and evaluation of the Virtual Engineering and Science Team (VEST) tool. VEST supports the efficient and cost-effective realization of on-board subsystem/instrument autonomy and contributes directly to the realization of an intelligent autonomous spacecraft. VEST supports the evolution of a subsystem/instrument model which explicitly represents correct vs. anomalous behavior. From that model, it automatically generates the code needed to support the autonomous operation of what was modeled. VEST facilitates the integration of the efforts of engineers, scientists and software technologists. This integration of efforts will be a significant advance over current development processes. The model, developed through the use of VEST, will be the basis for the physical construction of the subsystem/instrument and the generated code will support its autonomous operation once in space. The close coupling between the model and the code, in the same tool environment, will help ensure the correct and reliable operational control of the subsystem/instrument.