Future In-Space Operations Colloquium B Griffin Benefits of a Single-Person Spacecraft for Weigh less Operations

Brand Griffin

August 15, 2012

1 Why Look at a Single-Person Spacecraft? B Griffin

Past EVA Contributions Future NASA Plans Emphasize Weightless Operation Weightless Operations 13+ years

Add New Capability Samples Current to Improve Weightless Operations

5 to 11 yrs L1 Moon L2

Retrieval/ Repair

13 yrs Asteroid

20 yrs (weightless transit) Mars Assembly

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 2 Idea is Not New B Griffin

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 3 Single-Person Spacecraft B Griffin

No Reentry Venues ISS Operations

Weightless Operations

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 4 Implications of Low Pressure B Griffin

User Design ISS Atmosphere Low pressure space suit •Range of motion •Gas retention 101.3 kPa (14.7 psi) 29.6 kPa (4.3 psi) •Tactile feedback •Restraint •Low forces •Thermal •Minimum fatigue •Micrometeoroid •Comfort •Puncture Prebreathe

Glove pressure determines suit pressure

O O 29.6 kPa 2 Prebreathe O 2 21 % 2 100% (4.3psi)

Purge N2 101.3 kPa N (14.7psi) 2 N 79 % 2 Risk of Decompression

Sickness “Bends”

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 5 Less Overhead Time

Better Work Efficiency Index (WEI) B Griffin

EMU EVA Overhead Time

Gone Away Egress WEI 12.5-14 hr

Ingress + 2.5 hr

2.0 0.43 (ISS) 12.0

Direct access without prebreathing minimizes overhead

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 6 Many Parts and Adjustments are

Required for Proper Suit Fit B Griffin

Sizing Required to fit Avoid suit arms One Size Fits All Population Extremes • Sizing • Pressure

Common Eye Position

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 7 Displays and Controls B Griffin

Space Suit FlexCraft Minimal displays (20 character LCD) Multiple displays Pressure glove dexterity (full color flat panels) Out-of-sight controls Bare hand dexterity Sleeve mounted mirror Direct visibility of displays Sleeve mounted checklist Operate controls while Take hand off job to operate manipulators on the job Displays subject to local lighting Cockpit-type environment Alphanumeric Display

Cuff Check List

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 8 Getting to and from the Worksite B Griffin

Fly direct to worksite Hand-over-hand or SSRMS Emergency return is less than one minute Hand holds and worksites require rigid structure

Translation path required to/from airlock

Asteroids, Satellite & Telescope To be determined: Included: Propulsion Propulsion Tools ? Tools No MMUs ORUs ORUs Experiments Experiments SAFER is for emergency recovery Why Walk When You Can Fly

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 9 Translation Time B Griffin

Space Suit FlexCraft

Translation time is…affected by the crewmembers1 “MMU can return to the airlock from • Spacesuit configuration the furthest point on Space Station • Tools carried (about 146.30 m (480 ft)) in less • Tethers which must be moved than 1 minute.”2 • The “landscape” over which one is traveling MMU ~ FlexCraft Performance Increment 9 PRCM Replacement EVA MMU FlexCraft

Activity Time Delta V (m/s) 20* 19.5** (min.) Nom. Range (m) 137 same Hatch to Strella 9 Operation (hr) 6 same Translation to PMA1 15 Elapsed EVA Translation Propellant GN2 same Translation to SO 5 times Prop mass (kg) 5.9 14.2 Tool config, trans to worksite 14 No. Thrusters 24 same Stow tools, trans to SO 21 Thrust (N) 7.56 same Translation to PMA1 10 Tank Press (kpa) 20,684 23,442 Translation to Piers 16 * 13.7 m/s useful delta v ** At 450 kg mass 1 Extravehicular Activity Task Work Efficiency, C Looper and Z. Ney, SAE 2005-01-3014 2 Role of the Manned Maneuvering Unit for the Space Station, C. E. Whitsett, SAE

Quicker Translation is Safer and Means More Time on the Job

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 10 Foot Restraint Positioning Required

for Two Free Hands B Griffin

Prime Work Envelope Prime Vision and both hands in Work Envelope same location for all astronauts ISS Not all areas EVA accessible Max Prescribed translation paths Reach Requires worksite set up SSRMS slow (for EVA support 15 cm/sec) SSRMS not a cherry picker (requires IVA operations) Foot restraint adjusted to position astronaut’s Prime Work Envelope Asteroid (Near Earth Object) Little to no gravity No translation aids No EVA propulsion (MMU retired) Potential suit hazards

Satellite/Telescope Only HST EVA serviceable No translation aids Potential suit hazards Foot Restraint Allows two hand operations Reaction point for work loads

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 11 Low Cost Simulator Training

with in-Flight Refreshers B Griffin

Space Suits FlexCraft Neutral Buoyancy Laboratory Conventional Office

•Large unique facility •Conventional Office Projection Dome •Many skilled staff •Available projectors Field of View Divers •Available computers Suit techs •Simulation software Overhead crane •Few test personnel •Special equipment •No unique training •Many test personnel •No certification •Safety issues •No safety issues Two Simultaneous Tests On-orbit training •Certification Training •On-orbit training •Pressurized gases •Laptop platform •Control room •No on-orbit training

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 12 Grasp Limits and Protection B Griffin

Thermal Micrometeoroid/Debris and Radiation Even with active heating, touch temperatures are limited to short durations and narrow ranges (-140 to +240oF or –96 to 116oC)1

2

No Known Grasp Limits

30 Min. Grasp Limit EVA Thermal Grasp Limits 10 Min. Grasp Limit

-200 deg. F -100 deg. F 160 deg. F 320 deg. F

1. Advanced EVA Roadmaps and Requirements, Richard K. Fullerton, ICES01-2200 2. EMU Specification SVHS 7800, Rev BZ, pg 83 3. EMU Specification SVHS 7800, Rev BZ, 3.1.1.4.1 8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 13 Suit-Induced Trauma

B Griffin

FlexCraft Space Suit No trauma anticipated Suit induced trauma can occur even with minimal EVA time1

Delaminated Fingernails2

Swelling, Inflammation Knee abrasion

Restraint Vest (No work loads)

1 Extravehicular Activity – Challenges in Planetary Exploration, Carl Walz / Mike Gernhardt, 27 February, 2008, Third Space Exploration Conference and Exhibit, Denver, CO 2 Opperman RA, Waldie JM, Natapoff A, Newman DJ, Jones JA , Probability of spacesuit-induced fingernail trauma is associated with hand circumference, Aviation Space Environ Med 2010 Oct; 81(10):907-13. 8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 14 Operations Flexibility Mission length with alternating crew members B Griffin

ISS Operations

Day 1 Day 2 Day 3 Overhead Excursion Extensive overhead encourages long EVAs

Crew Rest Day Crew A Re-charge PLSS A

2 Astronauts Suits

Minimal overhead with no pre-breathe allows short or long excursions

Re- Re- Re- charge charge charge A B C (Auto- C A A (Auto- B (Auto- mated) mated) mated)

Different Astronauts Multiple Excursions FlexCraft Short or long excursions No day of rest between EVA Single-Person Not physically demanding No suit re-sizing for different crew Spacecraft : No strength or conditioning requirements No suit cleaning

No prebreathe with automated checkout allows rapid and frequent space access

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 15 Impact of Oxygen Environment

Space Suits and Host Spacecraft B Griffin 1980 Oxygen Suit Fire Fire and Materials in Different Oxygen Environments

Low Pressure Spiral Glove Drives Host Requirements

1

2 3

Dr. Michael D. Pedley, NASA/JSC/ES5, Dennis E. Griffin, NASA/MSFC/EH02

* Examples: (from Designing for EVA Applications, Gene Lutz, EVA Systems Project Office. Johnson Space Center, 13 February 2007) – A $150 Polar heart rate monitor may require $200K (or more) of engineering testing, analysis and certification before it can be used in the Space Suit – An emergency room EKG may require significant modifications to ensure the electrode leads do not detach from the crewmember in the Space Suit

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 16 Mass Comparison B Griffin

1012 kg (with airlock) 452 kg 460 kg (Wet) (Dry) 844 kg (without airlock (Orion), 4 EMUs)

440 kg

Shuttle Airlock The 1965 Cessna 150E 1,010 lb (460 kg)

286 kg (Dry with std equip) 136 kg (each)

Extravehicular Mobility Unit (EMU)

150 kg (each)

New Skykit Savannah 630 lb (286 kg) Manned Maneuvering Unit (MMU) (Representative, no longer available)

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 17 Step Function Capability B Griffin

Faster Horses? New Capability

“If I asked the people what they wanted, they would have said faster horses.”

Henry Ford

Better “Weightless” Suits? New Capability

8/15/2012 Benefits of a Single-Person Spacecraft for Weightless Operations 18