1. EVA and Mobility Systems Engineering
Michael Rouen
Robert C. Trevino
Joe Kosmo
NASA Johnson Space Center

2. Agenda EVA Challenges for Exploration Space Suit Assembly
System Requirements
Cardinal Elements
Human/Robotics & Analog Testing
Portable Life Support
Next Generation PLSS Development – Story of a Design Effort
Lessons Learned
Conclusion

3. EVA Challenges for Exploration
Robert C. Trevino
NASA JSC

4. EVA Systems Content Suit Systems EVA Tools and Mobility Aids
Life support systems and pressure garments required to protect crewmembers from ascent/entry, in-space, and planetary environmental conditions
EVA Tools and Mobility Aids
Equipment necessary to perform in-space contingency and planetary exploration EVA tasks
For CEV contingency EVA, may include drives, ratchets, sockets, restraint equipment, etc.
For planetary exploration, may include drills, hammers, walking sticks, geological test equipment, etc.
For planetary exploration, may include rovers, “assistant” robots, etc.
Vehicle Support Systems
Equipment necessary to interface the EVA system with the Constellation vehicles
May include suit mounting equipment, consumable recharge hardware, airlock subsystems, etc.
Ground Support Systems
Equipment and facilities required to test and verify EVA development and flight systems

5. EVA Suit Technology Challenges
Flexible, open architecture which can support multi-use and multi-destination operations with minimal system reconfiguration
Lightweight, highly mobile suits and dexterous gloves to increase crew productivity, minimize crew injury, and enable long-duration missions and high EVA use rates
Easily sizeable garments to fit a wide range of anthropometric sizes
Advanced life support systems to minimize weight and decrease consumables
Advanced power systems to minimize weight and increase cycle and shelf life
Advanced thermal control to increase crew comfort, decrease consumables, and enable multiple destinations
Dust and radiation protective materials and concepts
State of the art communications and computing capability for multi-media crew-ground interaction (e.g., integrated communications, high tech information systems, and heads-up displays)
Integrated human-robotic work capability to increase safety, efficiency, & productivity

6. Constellation EVA and Crew Survival Capabilities Needed
CEV to ISS
Constellation EVA and Crew Survival Capabilities Needed
Crew protection and survivability during launch, entry and abort (LEA) scenarios
**Apollo Program example: Cabin depressurization protection
Zero-gravity EVA capability for In-space Contingency EVA.
**Apollo Program example: Return from LEM to CM Contingency EVA
CEV to Lunar
Lunar Sortie/Outpost/Mars
Surface EVA capability for planetary exploration

7. EVA and Suit Systems Interfaces
CEV
Airlocks
Other Constellation Vehicles
Tools & Mobility Aids
Robotic Assistants
Power System
Comm System
Life Support
System
Thermal
System
Rovers
Habitat
Mobility
System
Structure/
Materials
Environmental
Protection
System
Emergency
System
Earth, In-space & Planetary Environments
Ground Support System
Lander
■Testing ■ Processing
■ Simulators/Analogs
■ Trainers■ MCC

8. Historical perspectives
Pressure (emergency only)
Umbilical only
pressure suit
Autonomous Surface
pressure suit
Simplified Apollo
PAST
Mercury
Gemini
Apollo
Skylab
Launch, entry suit
Autonomous 0-G EVA
Orlan (rear entry)
Launch, entry suit
PRESENT
Shuttle ACES
Shuttle/ISS EMU
ISS Russian Orlan
Russian Sokol
Soft upper body joints
Hard/Soft Hybrid
w/multi-axis mobility joints
Soft, lightweight
FUTURE
D Suit
I Suit
H Suit

9. Human Planetary Surface Exploration Experience
When Last Accomplished: 34 Years Ago!
Total number of 2-man EVAs 14
Total Duration of EVAs
81 hrs (3.4 days)
Average EVA duration
6 hrs
Total EVA traverse distance
59.6 miles
Shortest EVA distance
.16 miles Apollo 11
Longest EVA distance
21.9 miles Apollo 17
Apollo Mission 11 12 14 15 16 17
Number of EVAs conducted 1 2 3
Duration of EVAs (hrs.) per crewmember
2.8
7.8
9.4
18.6
20.2
22.1
Total traverse distance (miles)
0.16
1.25
2.1
17.4
16.8
21.9

10. Design Challenges
Early experiences with pressure suits on Gemini, Mercury and Apollo, along with non-existent Shuttle suit requirements in the programs early stages, led to the dual pressure suit approach that currently supports the Shuttle program.
The Advanced Crew Escape Suit (ACES) and the Extravehicular Mobility Unit (EMU) have served as the crew escape and extravehicular activity (EVA) pressure suits for quite some time.
The EMU, over 25 years old and facing significant obsolescence issues, is not compatible with the planetary environments of either the Moon or Mars and does not support the logistical requirements of long term missions. The ACES was not designed to perform EVAs.
The Russian Orlan and Sokol, while slightly varied in design, have many of the same limitations.
To support the Vision for Space Exploration (VSE) and Constellation objectives, it is necessary to develop a new pressurized suit system. One that is smart and evolvable.

11. Design Challenges (1 vs 2 vs 3 suits…)
The broad range of operational environments that this new suit system will be required to support poses some new challenges in selecting and designing the appropriate suit architecture.
However, the potential programmatic benefits of developing, operating and sustaining a common/evolvable single suit system architecture warrant a more thorough examination.
Development of a single integrated IVA/EVA suit system that satisfies all of the Constellation capability requirements versus a multiple suit approach is a programmatic decision that is at the forefront of the Exploration pressure suit development activity.

12. Design Challenges (1 vs 2 vs 3 suits…)
Some basic design challenges that need to be examined include
For IVA un-pressurized periods, the suit needs to support the crew for long periods of time (i.e. launch/entry/abort and in-flight powered phases). These phases alone would lean towards a lightweight, low-bulk, all fabric-based garment structure, minimizing hard-contact points.
For EVA, more gross mobility is necessary to support planetary exploration. For surface EVA alone, this would lean towards a more rigid, high bulk suit for operating in an upright position but could be uncomfortable to wear in a recumbent position as necessary for IVA phases.

13. The overall NASA goal is to get to Mars by using LEO and Lunar missions as stepping stones
Initial Prove-Out
System Verification
Improve Design
Etc.
Long Term Testing
Planetary EVA
Habitat
Etc.
Final Goal
Long Term Use
Reliability
Maintainability

14. Maintenance Goal = 4% of EVA Time Repair Goal = 1% of EVA Time
The number of EVA’s between overhauls will need to significantly increase in order to support future missions
Shuttle
ISS
Lunar/Mars(1)
Recertification 5X
Redesign
20X
5 EVA
25 EVA
300 – 500 EVA
Maintenance Goal = 4% of EVA Time
Repair Goal = 1% of EVA Time
Notes: (1) Assumes 2 year mission, EVA every other day

15. Schematic Need Statement
EVA Challenges
Schematic Need Statement
PLSS Packaging Driver
There are many technology components and system options already in development that may support VSE EVA requirements
Shuttle/ISS EMU
Component Weight: 73 lbs
Packaging Weight: 79 lbs
Total: 152 lbs
Mars: lbs
PLSS design objectives
Flexible (upgradeable & evolvable)
Mission maintainable
Small
Reliable
Lightweight
Robust
NASA must determine the optimum combination of these life support technologies (i.e., a functional support schematic) that meets the mission requirements

16. Technology Options to Consider
CO2/Humidity Control
Vent Flow and Pressure Control
Thermal Control
Oxygen
Power
Electronics
Packaging Concepts

17. Shuttle Extravehicular
Challenges
SSA
129 lbs.
PLSS
200 lbs.
Total
329 lbs.
PF: 2.20
SSA
xxx lbs.
PLSS
145 lbs.
Total
PF: 1.59
SSA
35 lbs.
PLSS
65 lbs.
Total
100 lbs.
PF: 1.24
Shuttle Extravehicular
Mobility Unit
Mk. III / DO2
Study
Advanced Technology
Spacesuit
XX% Reduction in
SSA Mass
XX% Reduction in
SSA Mass
51% Reduction in PLSS
Packaging Factor
59% Reduction in PLSS
Packaging Factor
0% Reduction in PLSS
Component Mass
43% Reduction in PLSS
Component Mass
XX% Reduction in PLSS Maintenance
XX% Reduction in PLSS Maintenance

18. Environmental Challenges to Consider
Thermal Control
Need for cooling
Need for thermal insulation
Dust Mitigation
Need for dust collection and/or removal
Radiation Protection
Need for human body protection

19. EVA Technologies Needed
Environmental Protection
Radiation protection technologies that protect the suited crewmember
protection technologies that provide self-sealing capabilities
Dust and abrasion protection materials or technologies to exclude or remove dust, withstand abrasion, and prevent dust adhesion
Flexible space suit thermal insulation suitable for use in vacuum and low ambient pressure

20. EVA Technologies Needed
Life Support System
Long-life and high capacity chemical oxygen storage systems for an emergency supply of oxygen for breathing
Low-venting or non-venting regenerable individual life support subsystem concepts for crewmember cooling, heat rejection, and removal of expired water vapor and CO2
Lightweight convection and freezable radiators for thermal control
Innovative garments that provide direct thermal control to crewmembers
CO2 and humidity control devices that, while minimizing expendables function in CO2 environment

21. EVA Technologies Needed
Sensors, Communications, Cameras, and Informatics Systems
Space suit mounted displays for use both inside and outside the space suit
CO2, biomed, radiation monitoring, and core temperature sensors with reduced size, lightweight, increased reliability, decreased wiring, and packaging flexibility
Lightweight sensors systems that detect N2, CO2, NH4, O2, ammonia, hydrazine partial pressures

22. EVA Technologies Needed
EVA Mobility
Spacesuit low profile bearings for partial gravity mobility requirements and are lightweight
Integration
Minimum gas loss airlocks providing quick exit and entry
EVA Navigation and Location
Systems and technologies for providing an EVA crewmember real-time navigation and position information while traversing on foot or a rover.

23. Space Suit Assembly
Enhancing the Capabilities of Space-Suited Planetary Surface Crewmembers
Potential Application of SOA & Emerging Technologies
Information Provided by: Joe Kosmo, JSC

24. Limitations of Existing EVA Architecture
The mass & mobility of current Shuttle/ISS space suit is not acceptable for use in a partial gravity environment due to the following:
Not capable of kneeling, bending, or prolonged walking
No dust control/protection
Chest-mounted display degrades arm/hand work envelop and foot visibility
Thermal protection (vacuum environments only) is too bulky, thus impeding mobility and glove dexterity/tactility
PLSS consumables require frequent replenishment or time & power to re-charge
Spacesuit and PLSS not totally serviceable by astronauts 24

25. Generic EVA System Needs
Space Suit System
Protection from hazards of new mission environment
Appropriate pressure to eliminate “bends” risk & pre-breathe requirements
Long-term durability & reliability to function over mission life cycle
Minimize weight and bulk
Simple re-sizing capability to accommodate various ranges of anthropometry
High degree of mobility & comfort
Provisions to accommodate & interface ancillary support elements (cooling garment, bio-sensors, communications system, PLSS, etc.)
Accommodate mission vehicle interface requirements
Portable Life Support System
Minimize use of expendables (water, oxygen, power)
Provide high level of reliability & safety
Minimize weight & volume by efficient component packaging
Provide ease of maintenance & repair during the mission
Maintain normal range of physiological aspects of crew during wide range of metabolic activities (O2 level, CO2 level, ventilation flow-rates, temperature conditions)
Provide integration capability with spacesuit system 25

26. Cardinal Elements of a Planetary Surface Spacesuit
MOBILITY:
Mandatory for walking (EVA traverses) and for negotiating rough terrain (rock fields, slopes, gullies)
Mandatory for EVA tasks, geologic exploration, deployment of surface equipment , maintenance & repair tasks
Mandatory for center-of-gravity control
Mandatory for ingress/egress airlocks and rovers (seated position)
Goal ; achieve near shirtsleeve range with low force required to reduce fatigue
ROBUSTNESS:
DURABILITY/LONG SERVICEABLE LIFE
High mission cycle life capability for multiple EVA’s (daily operations)
Abrasion/dust resistance
Impact/tear resistance
Incorporate long-term shelf-life/operational-life materials
WEARABILITY
Don/doff use (daily operations over long mission periods)
Handling capability (cleaning/storage)
LIGHTWEIGHT:
Reduce crewmember fatigue (assisted by low Lunar & Mars gravity)
Mass handling control (primarily “on-back” carry weight - - PLSS)
Reduce mission launch cost impact
SIMPLICITY:
Reduce system element complexity (incorporate modularity)
Ease of maintenance & repair 26

27. Cardinal Elements of a Planetary Surface Spacesuit
MOBILITY:
Mandatory for walking (EVA traverses) and for negotiating rough terrain (rock fields, slopes, gullies)
Mandatory for EVA tasks, geologic exploration, deployment of surface equipment , maintenance & repair tasks
Mandatory for center-of-gravity control
Mandatory for ingress/egress airlocks and rovers (seated position)
Goal ; achieve near shirtsleeve range with low force required to reduce fatigue
ROBUSTNESS:
DURABILITY/LONG SERVICEABLE LIFE
High mission cycle life capability for multiple EVA’s (daily operations)
Abrasion/dust resistance
Impact/tear resistance
Incorporate long-term shelf-life/operational-life materials
WEARABILITY
Don/doff use (daily operations over long mission periods)
Handling capability (cleaning/storage)
LIGHTWEIGHT:
Reduce crewmember fatigue (assisted by low Lunar & Mars gravity)
Mass handling control (primarily “on-back” carry weight - - PLSS)
Reduce mission launch cost impact
SIMPLICITY:
Reduce system element complexity (incorporate modularity)
Ease of maintenance & repair 27

28. Human/Machine Interactive & Sensory Capabilities
Voice and gesture actuation and command of EVA robotic assistant vehicles & systems
“Head’s up” helmet-mounted information display systems for space suit integration
On-suit computer and advanced informatics systems for voice-video-data transmission
EVA traverse mapping and route planning displays w/obstacle and hazards avoidance alerts
EVA robotic assistants w/manipulator arms and end-effectors that can be remotely teleoperated
“Smart” sensor systems for geologic sampling or environmental monitoring by humans or robots 28

29. Intelligence Enhancement Concepts “Smart Spacesuit”
Portable or suit/glove-mounted miniature, low-power environmental monitoring sensors:
External environment – radiation, UV levels, electromagnetic fields, contamination levels
Geologic/astrobiological sampling
Tactile feed-back
Helmet-mounted interactive “hand’s-free” visual display & voice activation systems:
Capability for system monitoring and control functions; “real-time” content
Autonomous terrain EVA traverse path mapping, navigation and crew tracking system:
Target recognition to include specified “land marks” or “science stations” and obstacle/hazards avoidance based on development of localized 3-D topographic map with appropriate “over-lays”
Non-invasive, low-power, wireless, oxygen compatible, medical/physiological sensors:
Blood N2, ECG, CO2, body-core temperature, muscle fatigue level
Adaptive collaborative system for documenting, recording, labeling, cataloguing and retrieval of EVA collected science data:
Geology/astrobiology science samples, photos, video, technical notes, etc. - - “smart” field data-log book
Autonomous system for EVA equipment monitoring, trend analysis, “self-diagnostics”, and malfunction response applicable to:
Life support system, airlock, rovers, robotic agents
Small, low-power, high intensity portable & suit-mounted lighting systems
Ultra Wide Band (UWB) communications system integrating voice, video, and data transmission capability 29

30. Current Analog Testing Efforts
Desert Research and Technology Studies (started in 1997)
Desert “RATS” is a combined group of inter-NASA center scientists & engineers, collaborating with representatives of industry and academia, for the purpose of conducting remote field exercises
For the future of space exploration, human/robotic interactive testing in a representative planetary environment is essential for proper development of specific technologies, & integrated operations
Provides the capability to validate experimental hardware/software, mission operational techniques & identify & establish technical requirements applicable for future planetary exploration
Currently, D-RATS remote field testing is being conducted in high desert areas adjacent to Flagstaff, Arizona & “dry-run” tests conducted at JSC

31. EVA Human/Robotic Testing
DRATS first started human/robotic testing in 1999 with the Astronaut/Rover (ASRO)
Study of human/robot interactive tests & investigating the division of labor between human & robot for planetary EVA exploration operations

32. EVA Human/Robotic Testing
Human/Robotic DRATS Testing
1999: EVA Robotic Assistant (ERA)
2002: Enhancement of human/robotic interaction with the Geological science trailer and the EVA Information pack
2003: USGS 1-G Lunar Rover Training Vehicle, 2nd Gen. science trailer and EVA Info. Pack
2004: Human/robot system evaluation of EVA informatics technologies & user interfaces, assessment of the electric tractor & Chariot functional performance characteristics
2005: Demonstrate large mass transport & handling, SCOUT systems evaluations
2006: “Day-in-the-life” EVA Crewmember tasks, regolith excavation, demonstration of combined robots (ATHLETE, Centaur, SCOUT, and K-10 w crewmembers

33. EVA Human/Robotic Testing
Human/Robotic DRATS Testing 2006
ESMD Surface Mobility
Development and demonstration of combined robot (ATHLETE, Centaur, SCOUT, and K-10) and two suited crewmember planetary activities in an appropriate terrestrial environment
SCOUT
To test the SCOUT vehicle while being driven by an onboard operator, a tele-operator at a remote location (base camp, ACES, ExPOC), and an autonomous system
To test advanced technologies that may prove useful in future SCOUT or planetary/Lunar rover development projects
SCOUT/Suit Objectives:
Evaluate cockpit design
Evaluate on-board suit recharge
Evaluate Communications, Avionics, and Informatics Pack (CAI-pack) system, functions, and user interaction

34. Michael Rouen Advanced PLSS Design Effort to Reduce Weight and Volume
Portable Life Support
Michael Rouen
Advanced PLSS Design Effort to Reduce Weight and Volume

35. PLSS Packaging Definition Function
Any item performing a major, useful life support function is a component to be packaged and is not packaging.
Harnesses, connectors, switches, brackets, wiring, and plumbing are packaging.
Structure is packaging, even in such special cases as the Shuttle valve module housing.
Function
Protect, Connect and Hold the PLSS and its components together internally and externally while providing access to PLSS components internally for maintenance and for technology change without extensive redesign impact.

36. Weight Pareto for STS PLSS & SOP

37. Goal
Seek ways to reduce the weight (mass) of PLSS packaging, and at the same time, develop a packaging scheme that would make PLSS technology changes less costly than the current packaging methods.

38. Packaging Dynamic Target Component Mass, lb 1 1.1 1.2 1.3 1.4 1.5 1.6
Interaction of Packaging Factor, Functional Component Mass and PLSS Total Mass 30 40 50 60 70 80 90
100
110
PLSS Total Mass
100#
95#
90#
85#
80#
75#
70#
65#
60#
Component Mass, lb
Target 1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9 2
Mass Packaging Factor

39. Mass Management: Mass vs. Weight
People on Mars will condition to Martian gravity.
So, people on Mars can only carry the same mass they can carry on Earth.
Backpacker’s rule % of person’s lean body mass for a full day.
Current suit system = the person’s mass
Need to reduce suit system mass by 2/3 or limit the work day.
Mass or Weight? Which is the concern?
Mass
Weight
EARTH
150 lbm = 68 kg
150 lbf = 667 N
MARS
57 lbf = 253 N

40. Evaluation & Mock-up
Decision Matrix Method Evaluation to identify weak and strong points of each concept to guide future work.
The lightest weight concept was selected for further work & a mock up was included in the plan to validate the concept and to assure the concept was indeed realizable.
The mockup will be used to evaluate
flexibility for technology change
In-use maintenance

41. Lessons Learned 3 2 1 2 3 4 5 VPF vs. MPF Frequent Overhauls
Specialized
Designs
Optimized
Designs
Flexible
Designs
A monument
Long-term Use 3
Shuttle
EMU
(2.3, 2.2)
Mass Packaging Factor 2
Apollo
(3.0, 1.7)
Orlan
(3.1, 1.5)
NASA
(2.9,1.3) 1 2 3 4 5
Volume Packaging Factor
Disposable
Monuments
Difficult to Maintain
Technology Specific
Mission Specific
Modular
Easy to Maintain
Technology Adaptable
Mission Adaptable
Fewer Overhauls

42. Mass Reduction Techniques
1) Breakthrough design concepts
Examples are: the gasbag outer cover, the combined base plate / hatch with through bolt mounted LRU’s.
2) Detail part weight optimization
This technique involves tradeoffs, material selection, changing requirements, reducing wall thickness, etc.
This needs to be done for every detail part in greatest weight order.
3) Minimizing volume and surface area
This technique became obvious in this effort.
The volume and surface area contributes to the overall mass.

43. Design Tools During the concept phase During the detail design phase
Pro-e® and Mechanica® used to rough out the concept.
Important to keep the modeling simple,
Mechanica stress analysis for stress in major structural members,
Local stress concentrations worked during the detail design.
Mathcad® for automation of trade study iterations.
MS EXCEL® spreadsheets for bookkeeping tasks.
Dytran® for the non-linear analysis of the fall cases.
During the detail design phase
Same tools used in more depth.
Possibly NASTRAN® instead of Mechanica for analysis in some situations. Nastran more versatile but demands more training.
SINDA® used for thermal analysis.

44. Lessons Learned Spend the time to get the concept right up front.
The more detailed the concept or design gets before it is found to be unacceptable, the more costly will be the recovery effort.
Prove out a new idea/concept with first cut analysis unless,
The basic concept depends on a unique idea – then a test must be run before concept approval.
In the conception phase the program needs experienced, inventive, engineers that won’t get bogged down in detail that is not needed until later in the process.

45. Lessons Learned The weight target is very difficult to meet.
Develop a weight control plan early with estimated or calculated weights so that corrective actions can be taken as soon as possible.
The concepts generated resulted in unacceptably high component operating temperatures.
Thermal analysis personnel available early in the concept phase.
Complexity of the heat transfer within PLSS prevents designer from doing own analysis.
Document the importance of the key requirements and re-evaluate periodically.
We lost sight of the weight goal even though that was the primary reason for the entire effort.

46. PLSS Development Conclusions & Products
Removing 2/3 of the PLSS mass is as hard as we expected.
Creativity is still needed.
Requirements conflict strongly in the problem.
Significant progress has been made - but, the concept requires further development.
Products
Design guideline document created in Task Two.
Extensive documentation of effort; contains proven procedures and design and analysis tools.
Concept Mockup

47. EVA Engineering Conclusion
The space suits and EVA systems needed to meet the requirements for sustainable and extended Lunar exploration present new challenges to NASA, other government agencies, academia, and industry. Innovative technologies and cooperation among the many involved organizations to address these challenges will be one of the keys to success for future space exploration.