Joshua Laub Jake Tynis Lindsey Andrews

 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)

 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)

 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 (  km)  Orbital decay is controlled by atmospheric density using a characteristic ballistic coefficient BC = m/C d *A

 Develop a prototype CubeSat deorbiting system  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: 1. Inflatable device 2. Deployable frontal area device

 Modular inflatable structure to increase drag  Considerations:  Shape  Folding/Packaging  Inflation system  Material  Structural

 Spherical:  Overlap panels to create spherical shape  High reliability on the adhesion of panels  Pillow:  Bond two sheets at edges  Less dependence on adhesion (less room for error)

 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 low- pressure inflatable structure Bradford Engineering

 Conditions: Durability and low density  Polyethylene terphthalate (Mylar)  Resistant to punctures, low cost but vulnerable to radiation over long periods of time  Polyimides  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

 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 1Figure 2Figure 3

 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

 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)

 US Air Force Plug and Play prototype system  Develop interfaces (assuming on- board avionics) to determine CubeSat orientation  Develop software to activate drag device deployment via transmitted radio command  Demonstrate deployment

 Estimated Finish Date: March 23 rd  (Allows time for unexpected delays)

ITEMCOST  6061 T6 Al  Kapton © /Mylar  Elastosil © S 36 adhesive  Suva 236fa gas  Misc. Electronics  Testing/Labor  ~$0.10 /cm 3  $200 /lb  $18.00 /tube  Pending Supplier  ~$200+ /module  Location/trade specific

 Goal: Create de-orbiting device for CubeSat  Inflation structure  General increased surface area  Challenges:  Weight  Packaging  Folding (if inflation device selected)  Signaling (Ground signal or on-board circuitry)

 Bradford Engineering. "Sold Propellant Cool Gas Generator."  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.".  Lokcu, Eser. "Design Considerations for CubeSat Inflatable Deorbit Devices in Low Earth Orbit." Old Dominion University (2010).  NASA. NASA Orbital Debris Program Office  —. NASA's Cubesat Launch Initiative  Office for Outer Space Affairs. "Space Debris Mitigation Guidelines of the Committee on the Peaceful Uses of Outer Space." Vienna: United Nations,  R. Janovsky, M. Kassebom, H. Lubberstedt, O. Romberg. END-OF-LIFE DE- ORBITING Strategies for Satellites. Bremen: OHB System AG, 2002.

 Questions?