This document summarizes a human factors engineering pathfinder activity for improving ground system designs. It discusses the importance of considering ground crew factors in system design. Sessions were held with design teams to identify human factors issues. Recommendations focused on improving workspaces, accessibility, controls and reducing potential for errors. The activity found that applying human factors principles early in design can help create safer, more usable ground systems.

1. 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

2. 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

3. 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

4. “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.

5. Ground Crew
Functions

6. 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

7. Flight System Example:
Waste Collection System Removal and
Re-Installation

8. Flight/Ground System Interface Examples
Quick Disconnects (QDs), Fluid and
Electrical Umbilicals:
- Flexhose connections inside the
spacecraft introduce risk of
collateral damage, additional work
content
- Human error potential (QD
mismates)
Spacecraft Handling Mechanisms

9. Personnel Protective Equipment Example
Self-Contained Atmosphere
Protective Ensemble (SCAPE) Suit
HSI Challenges:
- Dexterity/agility/flexibility
- Weight/bulkiness
- Heat stress/fatigue
- Negative pressure relief valve
- Electrostatic discharge
- Sizing/suit dimensions
- Visibility
- Communication

10. Similar Issues in Ground and Flight Systems
PREVIOUS
Comm
boxes near
crew module
ladder
NEW
ISS

11. Results of Human Factors Engineering
Pathfinder Activity for
Ground Systems

12. 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

13. 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

14. 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

15. 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

16. Let’s Design it Right the First Time!
Subject: CLV Mobile Launcher and access platforms with stairs and their impact to Ops
We just finished our ML PMR last week and I have attached a few of the slides that were
briefed. My concern is these show quite a few stairs that are now planned for access
from the ML to the Ares I vehicle once out of the VAB. I am concerned that this will
adversely affect the Operations for 20+ years and just might be a big impact. I
would like to get your take on how much of an impact this is. This will have a large
impact on the ML and the design, schedule, cost, etc., but I don’t want to look back
and 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 show
why the stairs will not work or why they may present an unsafe condition. So if you
could, 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% design
review on 11/29/07 with the final design due in December so this is getting very late in the
game 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

17. 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

18. 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

19. 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

20. Human Factors Concepts:
A Systems Perspective
Human-system interfaces include assemblers, maintainers,
operators, inspectors, and engineers

21. F-22 Example
"You've got to be kidding me....there
must be a handle in here somewhere!"

22. 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

23. Common Areas for Improvement in
Ground 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

24. Workspace
Some workspace positions may be difficult to reach.
In picture: Forward Reaction Control System (FRCS) work that
requires an awkward reach.

25. Damage/Error Prevention,
Detection and Recovery
Orbiter flex hoses and fluid lines
may get damaged during ground
operations, which can lead to
schedule delays and technical
issues.
Human Factors Design:
• Protect hardware during
inspection and processing
• Location, design of Before
temporary covers
After

26. Lifting, Work Envelope, Damage Prevention
SSME Dome Heat Shield Removal & Installation

27. Lifting, Work Envelope, Damage Prevention
SSME Dome Heat Shield Removal & Installation

28. Additional Modeling and Simulation Tools
 Posture, static strength, reach, clearance analyses
28

29. 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

30. 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

32. 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

33. Mobile Launcher Physical Data Interface (MPDI)
Human Factor Challenges (Examples) Recommendations & Potential Design Solutions
Work 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 reduce
connections. 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 lights
mismates, 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

34. Crew Access Arm (CAA)
Human Factor Challenges (Examples) Recommendations & Potential Design Solutions
Work envelope and access – actuator, energy For actuator area (motor/pulleys/cables): consider locating equipment
chain, 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 for
requirement). 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

35. Emergency Egress System (EES)
Human Factor Challenges (Examples) Recommendations & Potential Design Solutions
Controls – 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

36. Hypergol Servicing Systems
Human Factor Challenges (Examples) Recommendations & Potential Design Solutions
Work envelope – access arm at vehicle interface Provide adequate space on access arm to allow SCAPE personnel
needs 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 lift
servicing equipment and effort required to points. Minimize number of cables and hoses in higher traffic areas on
move/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
36
the level of redundancy and controls used by process escapes, process catches, and human errors.
the Shuttle system.

37. Upper Stage T-0 Tilt-Up Umbilical Arms (TUUAs)
(Includes updates after 30% design review)
Human Factor Challenges (Examples) Recommendations & Potential Design Solutions
Damage/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 the
umbilicals. 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 for
interface is only accessible by platforms in VAB (no maintenance and inspection of umbilical components and subsystem
on-pad access). Potentially limited platform area replacement items in nominal and vertical positions. Consider designing
during mating operation. custom access platforms.
Lifting, pushing, and pulling - ground plate Use lift assisting devices and guides to keep physical forces within
movement into mating position may require heavy recommended weight limits and protect from inadvertent, sudden arm
exertion 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 process
precision operation requiring 2 technicians; a escapes/catches (using HF-PFMEA or a similar method) and usability
mistake during the mating operation could cause 37
testing/evaluation using the prototype in the LETF to satisfy the requirement
incapacitating damage to the vehicle. for a human factors assessment in the 60% design review package.

38. Upper Stage Umbilical Plates
Human Factor Challenges (Examples) Recommendations & Potential Design Solutions
Connectors – if not connected properly, requires roll-back to Consider a trade study on number of guide pins or a custom
VAB. Limited space is available on the plate to access alignment tool. Extend crows feet to reduce the mating angle
connectors. 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) or
required. 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

39. Tilt-Up Umbilical Arm Visualization
39

40. 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

41. 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
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42. Human Factors Engineering Assessment Tool
Automatically Populated
after selecting section Free text
(Prev. Page)

43. 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

44. Thank you!
Questions?
44