# Presentation: 033297

## Challenges for Electronics in the Vision for Space Exploration*

**Kenneth A. LaBel**
**ken.label@nasa.gov **
**Co-Manager, NASA Electronic Parts and Packaging (NEPP) Program**
**Project Technologist, Living With a Star Space Environment Testbed (LWS SET)**
**Group Leader, Radiation Effects and Analysis Group, NASA/GSFC**
**** Radiation effects are the prime consideration in this talk. Reliability must ALSO be considered.***

## Outline

**Background – Radiation Effects on Electronics**
**Uniqueness of Exploration Systems Missions**
**Types of missions**
**Comparison to traditional missions**
**Electronic Parts and Exploration**
**Sample Electronics Radiation and Reliability Issues that Impact Space Exploration**
**Four-pronged Infrastructure Approach**
**Parts Management Process**
**Parts Reliability Capability**
**Radiation Effects Knowledge and Capabilities**
**Exploration-specific Technology Evaluation**
**Recommended Investment Areas**
**Summary Comments**

## Radiation Effects and Spacecraft

**Critical areas for design in the natural space radiation environment**
**Long-term effects causing parametric and /or functional failures**
**Total ionizing dose (TID)**
**Displacement damage**
**Transient or single particle effects**** (Single event effects or SEE)**
**Soft or hard errors caused by proton (through nuclear interactions) or heavy ion (direct deposition) passing through the semiconductor material and depositing energy**

***An Active Pixel Sensor (APS) imager***
***under irradiation with heavy ions at Texas***
***A&M University Cyclotron***

## Total Ionizing Dose (TID)

**Cumulative long term *****ionizing***** damage due to protons & electrons**
**keV to MeV range**
**Electronic Effects**
**Threshold Shifts**
**Leakage Current**
**Timing Changes**
**Functional Failures**
**Unit of interest is krads(material)**
**Can *****partially***** mitigate with shielding**
**Reduces low energy protons and electrons**

**Erase Voltage vs. Total Dose for 128-Mb ****Samsung Flash Memory**

## Displacement Damage (DD)

**Cumulative long term *****non-ionizing***** damage due to protons, electrons, and neutrons**
**keV to MeV range**
**Electronic Effects**
**Production of defects which results in device degradation**
**May be similar to TID effects**
**Optocouplers, solar cells, charge coupled devices (CCDs), linear bipolar devices**
**Lesser issue for digital CMOS**
**Unit of interest is particle fluence for each energy mapped to test energy**
**Non-ionizing energy loss (NIEL) is one means of discussing**
**Can *****partially***** mitigate with shielding**
**Reduces low energy protons and electrons**

## Single Event Effects (SEEs)

**An SEE is caused by a *****single charged particle***** as it passes through a semiconductor material**
**Heavy ions (cosmic rays and solar)**
**Direct ionization**
**Protons(trapped and solar - >10 MeV)/neutrons (secondary or nuclear) for sensitive devices**
**Nuclear reactions for electronics**
**Optical systems, etc are sensitive to direct ionization**
**Unit of interest: linear energy transfer (LET). The amount of energy deposited/lost as a particle passes through a material.**
**Effects on electronics**
**If the LET of the particle (or reaction) is greater than the amount of energy or ****critical charge**** required, an effect may be seen**
**Soft errors such as upsets (SEUs) or transients (SETs), or**
**Hard (destructive) errors such as latchup (SEL), burnout (SEB), or gate rupture (SEGR)**
**Severity of effect is dependent on**
**type of effect**
**system criticality**

***Destructive event ***
***in a COTS 120V ***
***DC-DC Converter***

## Uniqueness of Exploration Systems Missions

**The Vision for Space Exploration creates a new paradigm for NASA missions**
**Transport (Crew Exploration Vehicle – CEV), and**
**Lunar and Mars Exploration and Human Presence**
**If one considers the additional hazards faced by these concepts versus more traditional NASA missions, multiple challenges surface for reliable utilization of electronic parts.**
**The true challenge is to provide a risk as low as reasonably achievable (ALARA – a traditional biological radiation exposure term), while still providing cost effective solutions.**
**The following chart tabulates the exploration environmental challenges for electronic parts relative to traditional NASA missions.**

## Summary of Environment Hazards for Electronic Parts in NASA Missions

**Yellow indicates significant Exploration hazards**

## Discussion of the Hazard forElectronic Parts and Exploration

**As can be observed from the previous chart, Exploration Systems faces a unique electronic parts challenge not only for radiation exposure, but for reliability challenges as well.**
**Harsher environment than recent human presence missions (ISS, Shuttle)**
**Potentially, the combined hazard of traditional earth science (LEO) and space science (interplanetary) missions**
**Cost effectiveness may drive use of innovative commercial electronics usage to meet performance constraints**
**Is this unique to Exploration? No, but with the hazard faced, one must be careful to plan for radiation and electronic parts reliability**

## Types of Electronic Parts for Exploration

**One may view electronic parts for Exploration as meeting needs in three categories**
**Standard electronics**
**E.g., capacitors**
**Basic components**
**Standard building blocks**
**E.g., Field Programmable Gate Arrays (FPGAs)**
**Widespread usage in most systems**
**Custom devices not available as “off-the-shelf”**
**E.g., nuclear power or EVA**
**Needed for a specific application**
**Note: Commercial-of-the-shelf (COTS) assemblies (e.g., commercial electronic cards or instruments) also may be considered**
**Screening is more complicated than with ISS due to more extreme environment faced**
**In any case, coordination of the parts needs and parts management can be daunting for such a program**
**Infrastructure required to provide a cost-effective basis for electronic parts for Exploration**

## A Critical Juncture for Space Usage – Commercial Changes in the Electronics World

**Over the past decade plus, much has changed in the semiconductor world. Among the rapid changes are:**
**Scaling of technology**
**Increased gate/cell density per unit area (as well as power and thermal densities)**
**Changes in power supply and logic voltages (<1V)**
**Reduced electrical margins within a single IC**
**Increased device complexity, # of gates, and hidden features**
**Speeds to >> GHz (CMOS, SiGe, InP...)**
**Changes in materials**
**Use of antifuse structures, phase-change materials, alternative K dielectrics, Cu interconnects (previous – Al), insulating substrates, ultra-thin oxides, etc...**
**Increased input/output (I/O) in packaging**
**Use of flip-chip, area array packages, etc**
**Increased importance of application specific usage to reliability/radiation performance**

## Slide 12

## Implications for Electronics in Space

**With all these changes in the semiconductor world, what are the implications for usage in space? Implications for test, usage, qualification and more**
**Speed, power, thermal, packaging, geometry, materials, and fault/failure isolation are just a few for emerging challenges for radiation test and modeling.**
**Reliability challenges are equally as great**
**The following chart (courtesy of Vanderbilt University) looks at some of the recent examples of test data that imply shortfalls in existing radiation performance models.**
**Technology assumptions in tools such as CREME96 are no longer valid**

## Sample Modeling Shortfalls

***Reed-05***

## Current Status of Radiation Knowledge Maturity for Electronics

## Approach to Electronic Parts Assurance for Exploration

**What follows is a recommended four-prong approach with alliances to existing programs**
**The main alliance is with the NASA Electronic Parts and Packaging (NEPP) Program (OSMA) that provides limited ground-based technology evaluation and Parts Assurance on a “One NASA” basis.**
**NEPP works generic technology issues that are NOT specific to a Program, but of general NASA interest**
**Note: NEPP budget is ~ 1⁄2 of FY2000 levels due to cuts and full-cost implementation**
**What is being recommended is ****complementary**** to NEPP**
**Other alliances with flight testbeds such as LWS SET and New Millenium are also encouraged**
**The four prongs for electronic parts assurance are**
**Parts management and control**
**Reliability test and analysis capability**
**Radiation effects test and analysis capability**
**Exploration-specific technology evaluation**
***Environment models for electronics are outside of traditional parts assurance, but recommendations will be made later in presentation***

## Parts Management and Control

**Support coordination, management, and control of electronic parts as related to Exploration Missions**
**Support infrastructure issues required for successful electronic parts utilization**
**Vendor audits, standards committees, etc**
**Recommendation**
**Provide parts support at each center (min. 1 FTE/WYE per)**

**Complex new FPGA architectures include hard-cores: processing, high-speed I/O, DSPs, programmable logic, and configuration latches**

## Reliability Test and Analysis

**Goal: Provide dedicated infrastructure to support new and existing device evaluation**
**Provide a quick-turn capability for performing failure analyses on technologies of interest to Exploration**
**Keep evaluation capabilities on par with commercial technology advances**
**Allows cost-effective evaluation of space-specific issues**
**Keeps labs “state-of-the-art”**
**Recommendation**
**Utilize existing strengths at GSFC, JPL, GRC, MSFC, ARC, LaRC, and JSC. Examples,**
**GSFC and JPL are MAIN strengths for parts reliability efforts for the agency**
**GRC has capability for extreme temp, power, and RF**
**MSFC and JSC have historical base for electronics for human presence missions**
***Note: the cost for the capability to evaluate “state of the art” is on a rapid upwards spiral. Test equipment for state-of-the-art can run $Ms!***

## Radiation Effects Test and Analysis

**Goal: Provide dedicated infrastructure to support new and existing device evaluation for radiation specific issues**
**Provide a quick-turn capability for gathering radiation knowledge on technologies of interest to Exploration**
**Keep evaluation capabilities on par with commercial technology advances**
**Allows cost-effective evaluation of space-specific issues**
**Keeps labs “state-of-the-art”**
**Provide a heavy ion test capability on par with that developed for protons at IU for ISS for device evaluation**
**Recommendation**
**Utilize existing strengths at GSFC, JPL, and JSC**
**GSFC and JPL are recognized strengths for radiation effects for the agency (and the aerospace industry)**
**JSC has historical base for human presence coupled with electronics**
**Support high energy heavy ion test facility at MSU (National Superconductin Cyclotron Laboratory – NSCL) for commercial device/assembly evaluation**
**Includes purchase of time for Exploration technologies evaluations**

## Evaluation of TechnologiesSpecific to Exploration

**Goal: Provide evaluation of technologies of specific interest to Exploration**
**High and cold temperature**
**Long-life**
**Nuclear exposure, etc.**
**Recommendation**
**Utilize strengths at GSFC, JPL, GRC, MSFC, LaRC, ARC, and JSC**
**GSFC and JPL have traditional “One NASA” experience for electronic parts reliability leadership**

**Sample 100 MeV proton reaction**
**in a 5 um Si block.**
**Reactions have a range of types**
**of secondaries and LETs.**
***(after Weller, 2004)***

**P+**

## Electronics and Radiation Environment Investment Areas

**Understanding extreme value statistics as it applies to radiation particle impacts**
**Small probability risk analysis (if 1 in 1e9 particles can cause an effect, how do we test, model, and interpret for system risk?)**
**System Radiation Risk Tools**
**Interpreting device effects at the system level**
**High-Energy SEU Microbeam and Two-Photon Absorption Laser**
**Ability to determine fault cause in modern devices**
**Portable High-Speed Device Testers**
**Required to provide a cost-effective meaningful answer**
**Physics Based Modeling Tool**
**Provide an answer to shortfalls in tools such as CREME96**
**Radiation hardening of devices**
**Development of substrate engineering processing methods to decrease charge generation and enhance recombination in CMOS**
**Improved radiation hardening of sensors/detectors**
**Improved solar heavy ion model**
**System risk analysis requires this**
**Update to AE-8 and AP-8**
**Important to CEV and phasing orbits**
**Standard radiation environment “engineering-grade” sensor for all missions for long-term technology performance tracking and anomaly resolution. Commensurate technology database.**

## Summary

**This presentation has been a brief snapshot discussing electronics and Exploration-related challenges.**
**Radiation effects have been the prime target, however, electronic parts reliability issues must also be considered.**
**Modern electronics are designed with a 3-5 year lifetime typical.**
**“****Upscreening” does not improve reliability, merely determine inherent levels.**
**To cope with the uniqueness of the Exploration missions’ hazard, a program infrastructure and commensurate targeted research are suggested.**