Used with permission Infusing Human Factors in Ground System Designs Project Management Challenge 2010 Pat Simpkins, NASA/KSC Engineering Tim Barth, NASA Engineering and Safety Center
Outline Background Ground Crew Factors Ground Systems and Ground Support Equipment Pathfinder Activities Human Factors Overview Design Team Sessions Sample Results and Feedback Recommendations and Lessons Learned Current Status Discussion
Why are Ground Crew Factors Important? Space transportation systems involve many ground and flight systems. A Flight & concurrent engineering, “system of Ground Crew Launch, Landing & Recovery systems” development approach is Training Systems Systems required to optimize life-cycle performance. Apollo and Shuttle lessons learned Vehicle Flight Vehicle Systems Range Processing Systems Systems Exploration systems must be safe, sustainable, and affordable Payload NASA safety stakeholders: public, Processing Systems flight crews, workforce (including ground crews), and high-value capital assets (including spacecraft) Majority of life-cycle cost is People are the critical typically in operations, including ground crew operations elements of the system of Exploration systems: flight crews and ground crews
“Ground systems represent the largest overall cost for most space programs. However, testing of ground systems does not always get the same visibility as vehicle testing, for example. This is a major concern because problems with ground systems are just as likely to cause a mission failure as are vehicle problems. Also, ground systems tests are more prone to human error…” Excerpts from “Ground Systems Testing” by Norm Strang, Aerospace Corp.
Ground Crew Functions
Ground Crew Human-System Integration Challenges Flight systems Launch vehicles, spacecraft, payloads Flight/ground system interfaces Mechanical, fluid, and electrical connectors Ground systems Ground support equipment, ground crew training systems, launch control workstations, facility systems, personnel protective equipment (PPE), ground crew work instruction systems, repair/refurbishment workstations, and more
Flight System Example:Waste Collection System Removal and Re-Installation
Flight/Ground System Interface ExamplesQuick Disconnects (QDs), Fluid andElectrical Umbilicals: - Flexhose connections inside the spacecraft introduce risk of collateral damage, additional work content - Human error potential (QD mismates)Spacecraft Handling Mechanisms
Similar Issues in Ground and Flight SystemsPREVIOUS Comm boxes near crew module ladder NEW ISS
Results of Human Factors Engineering Pathfinder Activity for Ground Systems
Human Factors Pathfinder Core Team KSC Engineering KSC Constellation Ground Ops Project Office KSC S&MA KSC Spacecraft/Payload Processing Ames Human System Integration NASA Engineering and Safety Center 12
Pathfinder Goals Improve KSC designs by improving ground and flight crew interfaces with ground systems and GSE Tremendous opportunity to influence designs early Apply lessons learned from current ground ops to Constellation Demonstrate value of effectively using HFE capabilities in GSE design teams The expected outcomes are: Ground systems/GSE that are safer and easier (and therefore cheaper) for ground crews to operate and maintain during 20+ years of Constellation launch operations Fewer mishaps during ground processing where ground system/GSE designs are cited as contributing factors or causes 13
Shuttle Ground Operations Mishap Data Major Category Comparison 1254 Cause/Contributor Findings in 335 Mishaps 11-08-1996 to 09-30-2007 Design Issues (flight & ground systems) 17% Design Issues 23% Team Behaviors Procedures 4% Decision Process 4% Training Issues 4% Individual Attitude/Moods Task Specific Experience 5% 20% Supervisory Controls 5% Cultures and Policies 8% Other 10% Courtesy of USA Industrial and Human Engineering 14
Mishaps in Ground Operations For 11 NASA/KSC mishap investigation boards in FY06 and FY07: Several million dollars in direct costs (includes civil service board member labor and travel, board procurement costs, and estimated hardware damage costs) Plus additional direct costs such as contractor labor for amelioration, contractor labor for investigation boards, corrective actions (new procedures, training, etc.) Plus indirect costs Plus schedule impacts Plus personnel injuries 15
Let’s Design it Right the First Time!Subject: CLV Mobile Launcher and access platforms with stairs and their impact to OpsWe just finished our ML PMR last week and I have attached a few of the slides that werebriefed. My concern is these show quite a few stairs that are now planned for accessfrom the ML to the Ares I vehicle once out of the VAB. I am concerned that this willadversely affect the Operations for 20+ years and just might be a big impact. Iwould like to get your take on how much of an impact this is. This will have a largeimpact on the ML and the design, schedule, cost, etc., but I don’t want to look backand say we should have stopped the design and fixed this regardless.I am sure folks in my LX group are going to want some hard requirements that showwhy the stairs will not work or why they may present an unsafe condition. So if youcould, please respond with specifics as to why these stairs will impact specific operations.We plan to receive the 90% design on the ML structure on 11/14/07 and 90% designreview on 11/29/07 with the final design due in December so this is getting very late in thegame but we will need this system for 20+ years. Better to do it right the first time! • Systems engineering requires a system lifecycle perspective • Designing to requirements is necessary but not sufficient
Pathfinder Activities Day 1 Two-hour Human Factors Overview for GS/GSE Designers Days 2-4 Working Sessions with Design Teams Wrap-Up Session with Design Team Leads 17
Human Factors Overview Two-hour panel discussion designed to familiarize designers with basic HF principles before their working sessions First HF course developed specifically for ground system/GSE designers Target audience: fluid and mechanical systems Included KSC mishap data and examples Topics: Goals and Background Historical Perspective Design Topics and Examples Shop Floor Perspective Approximately 100 participants Sponsored by KSC Engineering Academy Prerequisite for the working sessions
Human Factors Engineering“The design of tasks, tools, systems and (work) environments that enhance the abilities and accommodate the limitations of people to produce safe and effective systems.” - Human Factors and Ergonomics Society (one of many definitions) 19
Human Factors Concepts: A Systems PerspectiveHuman-system interfaces include assemblers, maintainers, operators, inspectors, and engineers
F-22 Example"Youve got to be kidding me....theremust be a handle in here somewhere!"
Robust Designs Help Prevent Human Errors and Collateral Damage Unintentional human errors and collateral damage can occur in the design, development, operation, and vulnerable maintenance of any system A poorly designed (vulnerable) system enables average workers to make errors and/or damage systems A well designed (robust or resistant) system enables resistant workers to avoid errors and collateral damage
Common Areas for Improvement inGround Crew/Ground System Integration Workspace and work envelope Tool clearances Functional work areas Visual access Displays within field of view Lifting, pushing, and pulling Damage/error prevention, detection, and recovery Connectors Interface controls and information displays Labels and communications Consistent work practices Personal Protective Equipment (PPE) Work environment 23
WorkspaceSome workspace positions may be difficult to reach.In picture: Forward Reaction Control System (FRCS) work thatrequires an awkward reach.
Damage/Error Prevention, Detection and RecoveryOrbiter flex hoses and fluid linesmay get damaged during groundoperations, which can lead toschedule delays and technicalissues.Human Factors Design:• Protect hardware during inspection and processing• Location, design of Before temporary covers After
Lifting, Work Envelope, Damage Prevention SSME Dome Heat Shield Removal & Installation
Lifting, Work Envelope, Damage Prevention SSME Dome Heat Shield Removal & Installation
Human Factors (HF) Overview: Survey Feedback Things that were most liked: Specific design examples Application of HF principles to GSE designs Varied perspectives of speakers Looking at life cycle and integrated product teams User input to designs, designing with users in mind HF specialist as part of the design team Ground system/GSE Design Evaluation Worksheet Additional topics to address: How to force HF issues to be addressed in design approvals/reviews HF specs and standards HF for software, human-computer interaction (HCI) 29
GSE Design Team Sessions 9 design team sessions conducted 7 mechanical systems 1 fluid system 1 electrical system All teams completed the evaluation worksheet in advance Most teams were able to access current design packages/files during their working session Human factors workbook and reference guide provided Worked with team leads to identify the most significant HF issues that need to be addressed by the design teams Potential HF issues were documented Observation: different/overlapping perspectives were valuable SMA Professional Technician (end users) Operations Engineers Systems Engineers Human Factors Engineer 30
GSE Design Teams Mobile Launcher Physical Data Interface Crew Access Arm Emergency Egress System Mobile Launcher Hypergol Servicing System Upper Stage T-0 Tilt Up Umbilical Arms Upper Stage Umbilical Plates Mobile Launcher Access Platforms SRB Forward Skirt Umbilical First Stage Aft Skirt Umbilical 32
Mobile Launcher Physical Data Interface (MPDI)Human Factor Challenges (Examples) Recommendations & Potential Design SolutionsWork envelope – cable congestion. Increase spacing between connectors within a panel and between panels. Consider location of connectors on panels to be compatible with procedural sequence (start with inside connectors and work out to edge of panels). Make the most frequently used connections the most accessible.Functional work areas – high or low Consider using a horizontal configuration of smaller panels to reduceconnections. above-the-head or below-the-waist connections.Damage/error prevention and detection – Color code and label cables with large, bold fonts. Consider built-in lightsmismates, misalignments. for the MLP, possibly LED. Reduce/eliminate blind connections. Use keyed connectors. Provide visual feedback (color rings) and/or audible feedback for good connections.Damage/error prevention and detection – Separate more delicate fiber optic cables from the other cables.fiber optic cables. 33
Crew Access Arm (CAA) Human Factor Challenges (Examples) Recommendations & Potential Design SolutionsWork envelope and access – actuator, energy For actuator area (motor/pulleys/cables): consider locating equipmentchain, blast doors, access arm. on platforms with maintenance/inspection access for at least two workers. For energy chain: provide catwalk for access. Ensure blast doors can be accessed for inspection/maintenance via mobile platforms. Ensure there is access for maintenance/inspection underneath the crew access arm. Ensure adequate connection points for fall protection equipment in all areas.Lifting – actuator motor, ALAS hatch (potential Provide overhead attach point for motor (150-175 lbs) removal forrequirement). maintenance. Allow at least two people access to motor for positioning of hoist for removal. Possibility of ALAS hatch removal requirement (approx. 175 lbs in a confined space).Damage/error prevention – actuator. Provide guards on actuator motor and cables to limit cable wear & tear. Install a machine guard around motor for personnel safety. 34
Emergency Egress System (EES) Human Factor Challenges (Examples) Recommendations & Potential Design SolutionsControls – rail car brake release. Ensure brake release in car requires intentional activation (like ejection seats in aircraft).Personal protective equipment (PPE) – suited personnel. Levers/handles should accommodate personnel in flight suits, SCAPE suits, and fire/rescue suits.Functional work areas – track maintenance. Ensure easy access is provided for inspection/maintenance of track. Minimize inspection/maintenance tasks that require work overhead or below the waist. 35
Hypergol Servicing Systems Human Factor Challenges (Examples) Recommendations & Potential Design SolutionsWork envelope – access arm at vehicle interface Provide adequate space on access arm to allow SCAPE personnelneeds to accommodate at least two SCAPE maneuverability. Include SCAPE technicians on the design team.personnel and the control panel.Lifting, pushing, and pulling – weight/size of Consider hoist or rail crane to assist with equipment lifts. Include liftservicing equipment and effort required to points. Minimize number of cables and hoses in higher traffic areas onmove/maneuver the equipment. the platform.Connectors – quick disconnects vs. B-nuts. Perform a formal usability analysis in the SCAPE lab as part of the connector trade study.Damage/error prevention – fundamentally Perform an in-depth task analysis of hypergol servicing (HF-PFMEA,different hypergol servicing approach without ST- PRA, or other method). Proactively identify and mitigate potential 36the level of redundancy and controls used by process escapes, process catches, and human errors.the Shuttle system.
Upper Stage T-0 Tilt-Up Umbilical Arms (TUUAs) (Includes updates after 30% design review) Human Factor Challenges (Examples) Recommendations & Potential Design SolutionsDamage/error prevention – need reliable system Have one technician run the motor to lower umbilical to a marked position.feedback when technician lowers arm and mates the Use lock- out pins so umbilical can’t go below horizontal position and so theumbilicals. umbilical end does not over-extend and damage the vehicle.Work envelope – ground plate to flight plate Coordinate platforms used for vehicle access so they can also be used forinterface is only accessible by platforms in VAB (no maintenance and inspection of umbilical components and subsystemon-pad access). Potentially limited platform area replacement items in nominal and vertical positions. Consider designingduring mating operation. custom access platforms.Lifting, pushing, and pulling - ground plate Use lift assisting devices and guides to keep physical forces withinmovement into mating position may require heavy recommended weight limits and protect from inadvertent, sudden armexertion from technicians. movements. Provide carts to transport and maneuver air tuggers if VAB shop air is used.Umbilical placement and mating operation is a Include a systematic analysis of VAB processing tasks for potential processprecision operation requiring 2 technicians; a escapes/catches (using HF-PFMEA or a similar method) and usabilitymistake during the mating operation could cause 37 testing/evaluation using the prototype in the LETF to satisfy the requirementincapacitating damage to the vehicle. for a human factors assessment in the 60% design review package.
Upper Stage Umbilical Plates Human Factor Challenges (Examples) Recommendations & Potential Design SolutionsConnectors – if not connected properly, requires roll-back to Consider a trade study on number of guide pins or a customVAB. Limited space is available on the plate to access alignment tool. Extend crows feet to reduce the mating angleconnectors. and use a centering feature. Consider self-alignment approaches, a laser alignment system, and/or a linear mating system (vs angled mating system). Note: in the Feb 08 baseline, a “linear engagement after angular mate” design with centering feet is used. The alignment pins were eliminated. Consider a full design mockup and thorough usability testing to predict/demonstrate human reliability of aligning the plates and ensuring a correct mate.Lifting, pushing, and pulling - manual alignment of pivot feet is Consider hand grips (machined into plate or attached) orrequired. temporary handles so there is an easy way to hold/manipulate the plate without grabbing cables.Damage/error prevention and detection. Provide a visual indication on the collet engagement so that it is not overrun but fully connected. Need verification that feet are properly seated. 38
Tilt-Up Umbilical Arm Visualization 39
Recommendations Utilize experience and expertise of KSC technicians, as appropriate Continue soliciting design inputs from SMA and Ops Engineers Integrate human factors engineering into the systems engineering process Establish a KSC Engineering Human Factors POC to integrate HF support for GSE design teams Track and help resolve significant HF issues, including those identified during the pathfinder activity Lead development of HF tools, guidance, and additional resources Acquire additional HF expertise to provide embedded support to design teams, including completion of HF assessments and requirement verifications Determine criteria for a complete, valid human factors assessment HF assessment methods and approaches vary with GSE complexity, criticality/hazards, frequency of ground crew/GSE interfaces, etc. Address need for adequate consideration/evaluation of human factors in software and computer system designs Increase use of KSC modeling and simulation capabilities for evaluating designs from a HF perspective 40
Current Status Pathfinder core team members supported ongoing GSE design reviews Human factors worksheet and workbook were widely distributed KSC Engineering Directorate has obtained new contractor and NASA human factors engineering capabilities Formal human factors assessments are required products in the KSC Technical Review Process (KDP-P-2713) Human factors section in the KSC Engineering Design Handbook Also infusing human factors in Ground Operations Planning Task designs to complement hardware designs Operability enhancements HFE improvements to the NASA GSE design standard (NASA STD 5005) and the KSC design standard for Ground Systems (KSC STD 512) New section in the NASA Space Flight Human System Standard (NASA STD 3001) and Human Integration Design Handbook (HIDH) devoted to ground support activities Upper Stage mockup and simulations at MSFC to evaluate human- system integration issues with temporary GSE installed inside the vehicle Spreadsheet-based Human Factors Engineering Assessment Tool (HFEAT) developed to assist human factors engineers in verification of GSE design requirements 41
Human Factors Engineering Assessment Tool Automatically Populated after selecting section Free text (Prev. Page)
Primary Lessons Learned Proactive consideration of ground crew factors enhances the designs of ground and flight systems by: Reducing the risks of undetected ground crew errors and collateral damage that compromise vehicle reliability and flight/ground crew safety Ensuring compatibility of specific vehicle to ground system/GSE interfaces Optimizing the safety of ground systems/GSE Optimizing the operability of ground systems/GSE (reducing error potential, task complexity, task timelines, and total labor hour requirements) Improving task designs for ground operations that use the ground systems/GSE Reducing future re-design costs, such as system upgrades as a result of mishap investigations Many human-system integration challenges associated with flight systems/flight crews also exist with ground systems/ground crews HFE expertise is most effective when embedded in ground system design teams HFE methods, processes, and tools need to be part of the systems engineering process over the entire system life-cycle HFE concepts need to be infused as early as possible during the design phases and reinforced during all milestone reviews 43