Extra Vehicular Activity

Suits and Devices

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

EVA Suit Requirements Camera for exterior shots and face shots Direct voice com independent of rover Support EVA time of up to 10 hours EVA suits will be provided by HERCULES staff

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Technology Development Targets Skin tight suits Hard suits – “inflate” soft suit inside carbon fiber

shell Joint technology challenges Anti-dust coatings – electrostatic approach Vacuum/abrasion resistant coatings

EVA mobility EVA tools Garage and Resupply Aids

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Custom Suits – The old way

Apollo 17 Suit – Harrison Schmitt – Photo Courtesy of NASA

Gemini 4 Suit - Ed White – Photo Courtesy of NASA

The Apollo suit, including the life support backpack, weighed about 180 pounds.

(Source NASA http://history.nasa.gov/spacesuits.pdf)

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Modular Suit - Now

Shuttle EMU - Modular – Courtesy of NASA

(Source NASA http://history.nasa.gov/spacesuits.pdf)

Shuttle suit with the life support system, weighs about 310 pounds. The suit itself weighs about 110 pounds.

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Suit Mass/Life Support Requirements The life support system design goal - 10 hours EVA

Water: 2.4 kg Oxygen: 0.35 kg Food: 0.25 kg Waste Products Removal/Handling:

CO2: 0.4 kg Urine: 0.66 kg Solid Waste: 0.09 kg

Mass is in fabric, pumps, electronics, etc.

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Rover Suit Design Concepts/Sizing Mass < 100 pounds + modular life support for variable duration Straw man design:

One standard COTS pressure tank (0.727 kg of O2) + 1 smaller reserve tank, + third nitrogen tank

CO2 Removal: Lithium hydroxide or rechargeable metal oxide cartridges.

Food, Water, Waste Water ~ 90-100 ounces (ref. NASA STD-3000 Food dispenser – small built into helmet Waste collection: derived from the Shuttle Waste

Contamination System (WCS)(Reference: AIAA2003-

6276.SCOUT.pdf)

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Hard Suit Prototype

Hard Suit Prototype – not enhanced

Mark III Suit – Evaluation Unit - Photo Courtesy of NASA

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Skin Tight Suits – The Choice for Rovers Skin tight suits – Biosuit 1

Use mechanical counter pressure (MCP) for pressure production Active materials/piezo-electric

based pressure production Suit is donned like conventional

clothes – then shrinks to fit Smaller, more mobile Duration extension with recharge

packs on cart

Figure: http://mvl.mit.edu/EVA/biopics/DJN_MarsTwoView.jpg

Note 1: As described in “An Astronaut ‘Bio-Suit’ System for Exploration Missions, Newman, D. J.; Hoffman, J.; et al - Presentation to NIAC by MIT (ref. http://mvl.mit.edu/EVA/workshop.html)

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Augmented Hard Suit – Construction and Serious EVA

Dust free EVA/hardsuits mounted on habitat walls (thus system must clean a minimal area before re-dock) – Scaled lander docking technology – Suit docks

Enhanced mobility through movement amplifiers

Spring based hopper and gyroscopic stability options

Training required for use! Race Support/Rescue Personnel,

but probably not for rover teams

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Space Suit Feature Trades Trade of

Suit Types and suitability

Based on: ASTRONAUT PERFORMANCE: IMPLICATIONS FOR FUTURE SPACESUIT DESIGN: Frazer, A. L, et al, IAC-02-G.5.03

Type Advantages Disadvantages

Mechanical Counter Pressure

Ease of use, manueverable,

small

Less protection than other suits, waste collection

Modular Suits (Hard/Soft)

Current conventional

design, modular, low risk to design

Poor dust resistance, mass, size, pre-breathe

Hard Suit (not enhanced)

1 atm design, protection for

wearer

Reduced mobility. Increased size,

dust

Hard Suit (enhanced)

Enhance user capabilities, dust

free interior, 1 atm

Complexity, size, training

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Suit Technology – Race will Accelerate and Prove Concepts

Electrostatic charging effects – use dust properties to repel rather than attract dust Cleaning station – baghouse with electrostatic

precipitator components built into suit – plug in? Electrostatic dust removal from rover surfaces –

hatch areas, viewports, solar cells Skin Suits that integrate self-cleaning fabrics Disposable covers for contingency use suits

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Backpack to Dock

Suit docks 1

Adaptable to soft or hard suit designs

Note 1: “Suitport” - the NASA-Ames Hazmat vehicle, and the Hamilton-Sundstrand “Ready to Wear” Marssuit (Hodgeson & Guyer, 1998, 2000)

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Helmet Incorporates Video Features + Stereoscopic cameras Work lights Interior camera for facial

shot - video appeal Multiband Radio/suit

controls – Radio links to Rover Earth-comm link (satellite) Other EVA

Food/Water dispenser

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Rover Competion Drives Spiral Development of rover concepts will drive,

and in some cases, be driven by suit design

Race will serve to force suit evolution for focused needs and lead to diversified suit choices

Race will accelerate tool/EVA aid design

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

EVA Tools Design of suitable tools and EVA aids

facilitates competition goals Design for simplicity and utility and… Video appeal

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Lunar Crossbow Simple, effective, photogenic Ideal for projecting rescue, tow,

comm or even power lines Max Range = v0

2/g, where gmoon = 1.62 m/s2

A projectile launcher capable of 105 meters/second initial velocity will have a max range of ~ 6.8 km. Off the shelf sporting crossbows can propel 26 gram projectiles at this velocity

Future study: Review designs for fishing crossbows, FOG/M missiles for lunar use

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Regolith Hammer Simple hammer

device filled with regolith to aid in hammering stakes, etc., into the lunar surface

Bipod stabilization

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

EVA Scooter vs. Nonconventional Personal Locomotion

Trade – Amplified foot transport, conventional scooter, Segway type devise

Vendor/sponsor developed “common cycle” for all rovers

All will face dust challenges

Area needs more study!

Device Advantages Disadvantages

Scooter Fore/aft balance, ease of use

Size, front wheel dust

Amplified walker/hopper

Pogo or two footed spring devices

Training, safety

Segway™ Fast, easy to use, compact

Slopes, traction in 1/6 g and on regolith

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Garage and Way Station Technologies En route solar storm protection desirable for

team safety Way Stations need crew resupply and rescue

aids Way stations demonstrate autonomous

helpers

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Inflatable Way Station Garage

Self-erecting structure

Unmanned landing pod

Completed Garage

Unfolding two layerpetal-like structure with embedded inflatable beams

Regolith “pumps” while inflating

Idea adapted from: Chow, P. Y., and Lin, T. Y. ~1988:. ‘‘Structures for the Moon.’’ Engineering, construction, and operations in space, S. W. Johnson and J. P.Wetzel, eds., ASCE, New York, 362–374.

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Way Station Resupply/Rescue

LSRU – Lunar Surface Replaceable Units

Way station has drive under resupply device Dock port on top or

side of rover Resupply cannister

plugs in

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Resupply/Rescue/Transfer Concept

Way station automatically cleans rover dock area and attaches tunnel, crew crawls through and manually collects resupply

Could serve as crew transfer/rescue aid

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Autonomous Helpers Way stations will be deployed with an autonomous or remote

controlled mini-rover. Remote control or autonomous

Drive to some local high point (perhaps within 5 km - approx line of site) of the waypoint to aid in location of the waypoint once a rover gets close.

Provides rover inspection and damage assement utility Camera link to way station for video transmission to earth Minimal supply cache transportation to nearby rover Power from solar/battery combination Size (small enough to go underneath most rovers for inspection)

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Autonomous Helpers – Utility and Advertising

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Conclusion EVA Capability,

events crucial to race appeal

Race provides stimulus for EVA development

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Backup Charts

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

Inflatable Structure

Graphic from: Engineering, Design and Construction of Lunar Bases H. Benaroya; L. Bernold; and K. M. Chua, ASCE 0893-13212002

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

EVA-Lunar Soil Properties References http://rtreport.ksc.nasa.gov/techreports/2001repo

rt/200/206.html Key milestones: Experiment with actual lunar dust. Determine the charge generated on dust particles by

photoemission due to ultraviolet absorption. Expose materials to charged and uncharged lunar

dust under simulated lunar environmental conditions. Contact: Dr. C.I. Calle (Carlos.Calle-

1@ksc.nasa.gov), YA-F2-T, (321) 867-3274

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

EVA-Electrostatic Charging http://debye.colorado.edu/ZoltansJGR.pdf Contact charging of Lunar and Martian dust

simulants Quotes: “Our experiments demonstrated that both

regolith analog samples (JSC-1 and JSC-Mars-1) can become highly charged from a contact with either an insulating or conducting surface. The dust charge from contacts thus can be comparable or even exceed the charge a dust particle collects in a typical low temperature space plasma environment where the equilibrium charge is on the order of the electron temperature, Te, which is typically few eV [Horányi, 1996].”

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

EVA-Electrostatic Charging (cont’d) “The large contact charges described here

for planetary regolith analogs JSC-1 and JSC-Mars-1 suggest that grains lifted off airless planetary surfaces will carry a significant charge, regardless of ambient plasma conditions.”

2-Dec-04 USC 2004 AME 557 Space Exploration Architecture

EVA-Dust Properties – Research and Simulation

Minnesota Lunar Dust Simulant: “This simulant reproduces the chemical composition of lunar dust as well as its microscopic morphology. It does not reproduce well the mechanical properties of in situ lunar dust, due to the absence of Van der Waals (intermolecular level attraction) forces between grains at ambient pressure.”

Klinkrad H., U. Fuller, J.C. Zarnecki, "Retrieval of Space Debris Information from ESA's DISCOS Catalogue", Proc. ESA Workshop on Space Environment Analysis, Noordwijk, 9-12 October 1990 (ESA WPP-23)