Transcript International Space Station Final Project

International Space Station
Earth Preservation and Space
Exploration
Joseph Bermudez
[email protected]
December 15, 2009
ISS as the gateway to mankind’s
continued exploration in space
• Extend ISS support and scientific participation to all nations
• Define two main missions:
(1) Earth environment - monitoring and analysis
(2) Space exploration - flexible mission training,
technology development, and equipment testing
(Maintain current ISS hardware – replace modular
sections when required)
Earth Science Content:
Environment Study Emphasis
• Define a SPECIFIC scientific mission of
the International Space Station as Earth
environmental observation
• Mission objective would attempt definitive
environmental analysis to continually
refine conclusions regarding global
warming and greenhouse gas fractions
Earth Science Mission Requires
Inspiring Worldwide Participation
• Develop a global mission strategy tailored for the SOLE
manned orbital station
* as global, astronaut-tended Earth-monitoring node
* focus on global warming problem
• astronaut ambassadors further the cause of all mankind
and symbolize respect for human diversity
Space Exploration Content:
Flexible Mission Systems
• International participation
• Development of a flexible mission landing
vehicle applicable to Moon and Mars mission
• Formal training for Mars mission begins with
Moon flights
Engineering Challenge:
Spacecraft Radiation Shielding
• Huge radiation vulnerability exists beyond
Earth’s magnetosphere
* solar particle events
* galactic cosmic radiation
• Radiation shielding absolutely required
* passive (mass)
* active (magnetic field)
Active Radiation Shielding
• Huge energy and structural requirements
• Large mass penalty
• Theoretically possible with high temperature (70 K)
superconductors
• Effective against charged particles
• No generation of secondary radiation
• No operational system exists
Passive Radiation Shielding
• Effective for all radiation types
• Highly dependent upon material selection
and thickness for adequate protection
• Requires a novel approach due to extreme
energies of space radiation (e.g. lead
causes secondary radiation)
Passive Radiation Shielding
Material Effectiveness
________________________________
dose in Sieverts = dose in Gray × RBE
RBE = relative biological effectiveness
Shielding Thickness
thickness = (mass/area)/(mass/volume)
= (mass/area)/density
30 cSv annual dose limit applicable to 3 year mission
Passive Radiation Shielding Material
for High Energy Particles
• DENSE METALS (lead) - allow high energy particles collisions to
create secondary radiation (neutrons and nuclear fragments)
• LIGHT METALS (aluminum) - offer adequate shielding only at
prohibitive mass penalty
• CARBON FIBER (carbon) - provides adequate shielding at less
mass penalty than aluminum
• HIGH HYDROGEN CONTENT MATERIALS (liquid hydrogen, water,
polyethylene) - provide optimum protection with minimum
secondary radiation and lowest mass penalty
Shielding Materials Comparison
Material Density Neutron Absorption gamma
(kg/m^3) Cross-section (barns) (MeV)
Hydrogen
67.8
0.3326
2.223
Lithium
534
70.5
0.476
Boron
2080
767
0.478
Carbon
2267
0.0035
0.511
Aluminum 2700
0.232
1.809
( 1 barn = 1e-28 m^2)
Passive Radiation Shielding for
Gamma Radiation
• Gamma rays may be produced by nuclear
interactions when high energy particles hit any
spacecraft surface
• High density metals (lead, tungsten) provide the
most effective shield per unit thickness
BUT
lighter materials (carbon) may be matched to
certain gamma radiation environments
0.5 MeV Gamma Shielding Strategy:
Use Structural Material as a Shield
Material
Water
Carbon
Aluminum
Lead
Density
(kg/m^3)
1000
2267
2700
11,340
LAC
(m^-1)
9.7
19.6
22.7
164.0
1000*LAC/Density
(m^2/kg)
9.699
8.646
8.407
14.46
(LAC = Linear Attenuation Coefficient, gamma)
Carbon fiber structure could serve a dual role as structural
material and gamma shield.
Potential Research Area for Passive
Radiation Shielding
• Possible application of the macroscopic Whipple
micrometeoroid shield effect to the atomic/molecular
scale using multi-layered shielding materials
* aluminum/borated aluminum
* carbon fiber nanotubes (hydrogen added)
* polyethylene (boron added)
* boron carbide (B4C)
• Different material interactions progressively diffuse
high energy through a series of nuclear collisions
gradually absorbed into polyethylene
Spacecraft Wall
(27.1 g/cm^2)
Magnesium Whipple Shield (blue)
2 mm thick
Carbon Fiber Struts (gray)
Vectran Sheet (green)
Carbon Fiber Outer Wall (gray)
1 cm thick
Borated Polyethylene (red)
7.6 cm thick
Carbon Fiber Inner Wall (black)
10.5 cm thick
International Starship
Hypothetical spacecraft serving
both as a space station and an
interplanetary spaceship
•
Demonstration project for
application of the passive radiation
shielded spacecraft wall
•
50 m radius rotating at 4 rpm to
generate 1g equivalent
•
•
Nuclear power
International Starship:
Physical Description
• Circular manned spacecraft
* Perimeter exercise track
* Exercise room
* Sick bay
* Agriculture (hydroponics)
• 50 meter radius
• Rotating at 4 rpm to create 1g equivalent
• 4 center spokes
• 4 engines mounted between spokes
• Passive radiation shielding with calculated 99% shield efficacy at 3
years due to boron burn-up
• Space Station AND Space Exploration Vehicle
• Nuclear power
Starship Calculations:
Empty Mass WITHOUT Engines
ITEM
MASS (kg)
Whipple Shield Bumper
39,124.4
Whipple Shield Stuffing
1,067.6
Whipple Shield Struts
1,000.0
Carbon Fiber Outer Wall
189,907.0
Borated Polyethylene Shield 751,716.0
Carbon Fiber Inner Wall
1,994,025.0
Titanium Central Spokes
20,000.0
___________
TOTAL
RATIONALE
micrometeoroids
micrometeoroids
micrometeoroids
radiation
radiation
radiation/structural
structural
2,996,840.0 kg
(compare to ISS completed mass of 471,736 kg)
References
1.
2.
3.
4.
Space Physiology, Jay C. Buckley, jr., (2006), Oxford
University Press, p. 54-74.
Space Biology and Medicine, Huntoon, Antipov,
Grigoriev, (1996), American Institute of Aeronautics
and Astronautics, p. 349-418.
Wilson, Cucinotta, Nealy, Clowdsley, Kim, Deep Space
Mission Radiation Shielding Optimization, (2001),
Society of Automotive Engineers, Paper Number
01ICES-2326,
Rapp D, Radiation Effects and Shielding Requirements
in Human Missions to the Moon and Mars, The
International Journal of Mars Science and Exploration,
(2006), p. 46-71.
References
5. Levy R, Sargent Janes G, Plasma Radiation Shielding,
American Institute of Aeronautics and Astronautics, Vol.
2, No. 10, 1964, p. 1835-1838.
6. Levy R, Radiation Shielding of Space Vehicles by Means
of Superconducting Coils, AVCO-Everett Research
Laboratory, ARS Journal, (1961), p.1568-1570.
7. Goksel B, Rechenberg I, Surface Charged Smart Skin
Technology for Heat Protection, Propulsion, and
Radiation Screening, Institute of Bionics and
Evolutiontechnique, TU Berlin, (2004), p. 1-7.
8. Shepard S G, Kress B T, Stormer theory applied to
magnetic spacecraft shielding, Space Weather, Vol. 5,
2007, S04001, p. 1-9.
References
9. Schimmerling W, Overview of NASA’s Space
Radiation Research Program, Gravitational and
Space Biology Bulletin,16(2), June 2003, p. 510.
10. Radiation Protection: A Guide for Scientists,
Regulators, and Physicians, Jacob Shapiro,
(2002), Harvard University Press, p. 1-100.
11. Radiation Shielding, J Kenneth Shultis,
Richard E Faw, (2000), American Nuclear
Society.
12. Atoms, Radiation, and Radiation Protection,
James E Turner, (2007),3rd Edition, Wiley VCH.
Credits
Image Credits
(www.yahoo.com)
•
•
Graphs from Yahoo images
* slide 7
* slide 9
* slide 10
Diagram from Yahoo images
* slide 8
Graphic Credits
(Will Russell)
•
•
Spacecraft Wall Section Diagram
* slide 18
Hypothetical Starship
* slide 19