Dischinger, Charlie

Griffin, Brand

NASA Technical Reports Server

Low Cost Space Demonstration
for a Single-Person Spacecraft
Brand Griffin
Gray Research/NASA, MSFC Engineering, Science, and Technical Services Contract
Charlie Dischinger
NASA, MSFC
41st ICES, 17–21 July 2011, Portland, Oregon
<Company Logo>
https://ntrs.nasa.gov/search.jsp?R=20120016674 2019-08-30T23:07:34+00:00Z
What is a Single-Person Spacecraft?
2
1954 2003
Bottle Suit SCOUT
19851968
MAWSPod
2010
FlexCraft
(née MAWS)
Key attributes of baseline concept:
Operates with a host spacecraft
Cabin atmosphere is the same as the host
Includes a propulsion system
Uses manipulators
Baseline:  FlexCraft (Multiple Venues with Human and Robotic Operations)
Idea is not new and there are many configurations
FlexCraft Configuration
3
Multiple Venues with Human and Robotic Operations
Venues Operations
1.28 m (50 in.)
ISS Hatch Opening
Mission and Launch Vehicle
4
Two Launch Vehicle Options
Vehicle Falcon 1e
Minotaur I w/ 
61” fairing
Data source Guide Guide
Launch Site RTS CCAFS*
Inclination 9.1 28.5
Notes: 1,3,4 1,2
Circular Orbit Alt 
(km) Payload to orbit (kg)
200 1005 577
250 970 565
300 975 553
350 955 541
400 940 527
Max longitudinal 
CG offset for 
500kg payload 
(m)
1[8] 1.0 [7]
Upper Stage Target
ISS, NEO and Satellite tasks 
Bare bones Demonstrator Significant Margin to 350 km
Short Mission
(Reduced Cost)
1-3 days
on-orbit
Within mass and cg limits
DAS estimate for frontal area
Area (m2) Area/Mass
Fixed 3.04 0.00869
Grav grad 3.03 0.00866
Tumbling 2.83 0.00809
Addnl area protrusions (m2) 0.1
Area/Mass for analysis 0.00897
Falcon 1e    30 days
Minotaur 1   20 days
Safe Re-entry
Minotaur 1 Falcon 1e
Configuration
5
Pressure Vessel Secondary Structure Subsystem Packaging MMOD Shield
System Demonstrator TRL
1 2 3 4 5 6 7 8 9
Structures
Electrical
Thermal
Propulsion
GN&C
Comm
Robotics
FlexCraft
Predicted Mass 
(kg) inc MGA
1.0 Structures 123.86
2.0 Propulsion 52.20
3.0 Power 46.78
4.0 Avionics 53.13
5.0 Thermal 23.38
6.0 Separation Ring 8.87
Dry Mass 309.26
7.0 Non-Prop Fluids 1.22
8.0 Cargo/Payload 65.49
Inert Mass 59.22
Total Less Propellant 368.48
9.0 Propellant 14.25
Total Gross Mass 382.73
Mature Technologies
AIAA Standards for MGA
Mockups
6
Pressure Vessel Enclosure
5th % Female
99th % Male
Full Scale Sizing Mockup
Adjustable
Adjustable
MMU and FlexCraftSizing Mockup
Systems are Available to Support Launch in 3 yrs.
7
Longest Lead Times:
Flight Computer (up to 16 months)
Thruster Triads (12 months)
Primary Battery (12 months)
GPS System (12 months)
“Design to Availability”
• Cold gas (nitrogen) propulsion system
• Eight thruster triads
– Provides rotational and translational control
– Redundant A and B sets
• Total maneuver propellant = 14.2 kg (31.4 lbm)
– Assumes tank drain from 3400-to-250 psi
– Total loaded nitrogen = 15.5 kg (34.1 lbm)
Overview
• VACCO 2 lbf thrusters (same as MMU)
• COTS tank:  1900 in3, 3400 psi
• Structural Composites Industries
(Worthington Cylinders Company)
• Redundant A and B systems
• High TRL
Key Features
Component Qty
Unit 
Mass
(kg)
Basic 
Mass
(kg)
AIAA 
Category
& Code
MGA
Predicted 
Mass
(kg)
Comments/Informatio
n
Thruster Triad 8 1.41 11.28 A5 2% 11.51 VACCO 2 lbf cold gas thruster triad
Pressure Vessel 2 15.65 31.30 A5 2% 31.93 Worthington Cylinders Tank
Regulator/Relief 
Valve 2 0.36 0.72 C4 4% 0.75 MMU component
Crossfeed Valve 2 0.45 0.90 E2 12% 1.01 MMU component
Isolation Valve 2 1.20 2.40 C4 4% 2.50 MMU component
Quick 
Disconnect 2 0.41 0.82 C4 4% 0.85 MMU component
Filter 2 0.25 0.50 E1 18% 0.59 Estimate
Pressure 
Transducer 2 0.20 0.40 C4 4% 0.42 Typical Value
Pressure Gauge 2 0.08 0.16 C3 8% 0.17 MMU Component
Service Valve 2 0.21 0.42 C4 4% 0.44 MOOG Low Pressure Valve
Lines & Fittings 1 1.74 1.74 E1 18% 2.05 Estimate
Total Dry Mass: 50.64 kg 3.1% 52.20 kg
Propulsion System   (Repackaged MMU)
Pressure Vessel Stress Plot
TABLE 4‐1. PAYLOAD CG 
PARAMETRIC DESIGN LIMIT 
LOADS
Payload Mass
1600 lbm (725.7 kg)
Axial (G) 
max/min Lateral (G)
Liftoff 3.83/0.27 0.62
Pre‐Transonic Resonant Burn 5.05/0.83 0.02
Transonic 5.13/1.52 1.23
Supersonic 3.41/3.40 1.96
Stage 2 Ignition 3.93/‐0.35 4.05
Stage 3 Ignition 6.79/0.00 0.78
Stage 3 Burnout See Figure 4‐3 TBS
Stage 4 Burnout See Figure 4‐3 TBS
Launch Vehicle & Loads:
Minotaur loads from Payload Planner’s Guide
Integrate with standard Payload Attach Fairing 
Minimum Natural Frequency > 25Hz
Factors of Safety
Yield: 1.25
Ultimate: 1.4
Pressure Vessel: 2.0
Materials:
AL 2219 – T87: Pressure Vessel Structure
AL 7075 – T651: Ringframes & Spars
Lexan 1500 Polycarbonate: Dome
Minotaur Launch Loads
Structures
Avionics
11
After the Demonstration
12
Acknowledgement
The authors wish to thank the technical contributions 
from Jerod Andrews, Mike Baysinger, Pete Capizzo, 
Leo Fabisinski, Terrie Gardner, Randy Hopkins, 
Linda Hornsby, David Jones, Dauphne Maples, Andy 
Philips, Clay Robertson, David Reynolds, Dan 
Thomas, John Smith, David Smitherman, and Janet 
Washington.
In addition, the authors wish to acknowledge Reggie 
Alexander and Don Krupp for management 
guidance throughout the study.


Low Cost Demonstration for a Single-Person Spacecraft

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