Fall Final PowerPoint Presentation

Report
Joshua Laub
Jake Tynis
Lindsey Andrews
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Small, lightweight satellites
Developed by California
Polytechnic State University and
Stanford University
Relatively low cost
Short development time
Auxiliary payloads on larger
missions
Size = 10 cm cube (1 U up to 3U)
Total Mass < 1 kg
Orbital altitudes as great as 900 km
(ISS is about 350 km)
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Definition: Man-made objects in orbit
Around 19,000 objects > than 10 cm DIA
Velocities on the order of 7.4 km/s
NASA/IADC Guideline: Man-made orbital debris
must have lifetime of 25 years or less.
Challenger (Fleck of Paint)
Endeavor (unknown debris)
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Increasing volume of CubeSat missions contributes to
orbital debris
Due to their small size, mass, and frontal area
CubeSats have orbital lifetimes on the order of 500
years at typical deployment altitudes ( 1000 yrs @
900 km)
Orbital decay is controlled by atmospheric density
using a characteristic ballistic coefficient
BC = m/Cd*A
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Develop a prototype CubeSat deorbiting system
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Basis: Even at 900 km altitude, atmospheric density is
sufficient to create a small amount of aerodynamic drag (V
= 7.4 km/s). Increasing the cross sectional area will increase
the drag, decrease ballistic coefficient, and deorbit the
CubeSat faster.
Possible Solutions:
Inflatable device
2. Deployable frontal area device
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Modular inflatable structure to increase drag
Considerations:
Shape
 Folding/Packaging
 Inflation system
 Material
 Structural
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Spherical:
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Overlap panels to create spherical
shape
High reliability on the adhesion of
panels
Pillow:
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Bond two sheets at edges
Less dependence on adhesion (less
room for error)
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Gas cylinder initiated by ground signal or on-board
timing circuit
Must consider added weight and volume for power
source
Must be cautious of over-inflation or gas leaks
Gas: Liquid that vaporizes upon release into lowpressure inflatable structure
Bradford Engineering
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Conditions: Durability and low density
Polyethylene terphthalate (Mylar)
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Polyimides
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Resistant to punctures, low cost but vulnerable to radiation
over long periods of time
Good mechanical properties
External chemical coating necessary to prevent atomic
oxygen degradation
Kapton
Thicknesses of about 25 – 50 microns
Coatings of about 0.1 micron
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Insert a conductive strip inside the inflatable
structure to allow a ring of electrical current to flow,
which would interact with the Earth’s magnetic field
F = I*L x B
Figure 1
Figure 2
Figure 3
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Main challenges:
Orienting the CubeSat
 Controlling the current
(timing)
 Ensuring that the dissipated
heat does not degrade the
adhesive
 New folding characteristics
 Adequate battery life to
produce current
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Increase surface area for drag
Extending panels that can swing out to
increase CubeSat surface area
Panels could be used for solar power if
desired
Main challenge: Weight constraints
Benefits: No concerns about leaks or
folding patterns
Challenges: Additional mechanisms and
moving parts, requiring power and
volume (pointing at the sun may not
produce drag cross section)
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US Air Force Plug and Play prototype
system
Develop interfaces (assuming onboard avionics) to determine CubeSat
orientation
Develop software to activate drag
device deployment via transmitted
radio command
Demonstrate deployment
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Estimated Finish Date: March 23rd
(Allows time for unexpected delays)
ITEM
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6061 T6 Al
Kapton© /Mylar
Elastosil © S36 adhesive
Suva 236fa gas
Misc. Electronics
Testing/Labor
COST
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~$0.10 /cm3
$200 /lb
$18.00 /tube
Pending Supplier
~$200+ /module
Location/trade specific
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Goal: Create de-orbiting device for CubeSat
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Inflation structure
General increased surface area
Challenges:
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Weight
Packaging
Folding (if inflation device selected)
Signaling (Ground signal or on-board circuitry)
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Bradford Engineering. "Sold Propellant Cool Gas Generator." 2006.
<http://www.bradford-space.com/pdf/be_datasheet_spcgg_sep2006.pdf>.
California Polytechnic, State University. "CubeSat Design Specification Rev.12."
D.C. Maessen, E.D. van Breukelen, B.T.C. Zandbergen, O.K. Bergsma.
"Development of a Generic Inflatable De-Orbit Device for CubeSats." (n.d.).
DuPont. "Summary of Properties for Kapton Polymide Films."
<http://www2.dupont.com/Kapton/en_US/assets/downloads/pdf/summaryofpr
op.pdf>.
Lokcu, Eser. "Design Considerations for CubeSat Inflatable Deorbit Devices in Low
Earth Orbit." Old Dominion University (2010).
NASA. NASA Orbital Debris Program Office. 2009.
<http://orbitaldebris.jsc.nasa.gov/>.
—. NASA's Cubesat Launch Initiative. 2010.
<http://www.nasa.gov/directorates/somd/home/CubeSats_initiative.html>.
Office for Outer Space Affairs. "Space Debris Mitigation Guidelines of the
Committee on the Peaceful Uses of Outer Space." Vienna: United Nations, 2010.
R. Janovsky, M. Kassebom, H. Lubberstedt, O. Romberg. END-OF-LIFE DEORBITING Strategies for Satellites. Bremen: OHB System AG, 2002.
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Questions?

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