ODU CubeSat MAE 435 Midterm Presentation – June 21, 2016 Cornelius Aaron Malcom-Scott Edwards Heather Culley Josh Frechem Jonathan DeGroff Owen Parkinson Project Manager: Tevon Taylor

Purpose The purpose of this project is to perform scientific research, for a 1U CubeSat incorporating an aerobrake, to predict orbital decay, and build prototype elements that can demonstrate communication and data transmission capabilities.

What is a CubeSat? Described by Cal Poly CubeSat Design Specifications 10 cm cube up to 1.33 kg mass Relatively low cost and development time Makes space more accessible to universities and private interests

Typical “1U” CubeSat Image source:

Chassis style/size comparison Image source:

Virginia CubeSat Constellation Proposed by Virginia Space Grant Consortium (VSGC). Project includes undergraduate teams from ODU, Virginia Tech, the University of Virginia, and Hampton University. Constellation will consist of three CubeSats with common objectives. Selected for NASA funding as of April 2016.

Science Investigation Measure orbital decay of constellation to develop database of atmospheric properties. Region of interest is “thermosphere” (90 to 600 km altitude). Atmospheric density varies appreciably both with solar time of day and as a result of solar activity. Understanding the relationship is necessary to predict orbital lifetimes. Accelerometer data collected by constellation will help model atmospheric activity with respect to both time and location.

Science Investigation (cont.) UVA and VT CubeSats will be similar to each other. ODU CubeSat will feature a deployable drag brake and will achieve a different ballistic coefficient.

Science Investigation (cont.) Data will be transmitted directly to ground-based receiving station. Data may also be uploaded to the Globalstar telecommunications constellation. This approach offers improved coverage compared to a ground link.

Technology Investigation Develop a system to determine and communicate satellite position across constellation. Will enable constellations to make multi-point observations of atmospheric phenomena. Can be used to develop collision avoidance systems.

Chassis Main structure of satellite (a.k.a. frame or bus)

Chassis Size is constrained by P-POD launcher

Chassis The ODU team has chosen to design and additively manufacture our CubeSat chassis for several reasons: Lower cost Lower weight Demonstration of effort/innovation Proven by previous NASA CubeSat missions

Chassis Windform XT Polyamide reinforced with carbon Manufactured through selective laser sintering Can be machined after fabrication

Chassis

NASA 3U Windform CubeSat

Drag Brake Design concept from the NASA Echo Satellite Project Sublimating benzoic acid as gas generator Mylar inflatable to prevent from atomic oxygen degradation. Cross sectional of area 1 m^2

Drag Brake (cont.)

Drag Brake – Vacuum Chamber Testing Vacuum Chamber at NASA

Power System Clyde Space 3G 1U EPS Clyde Space solar panels Clyde Space integrated battery

Clyde Space 3G 1U EPS The Clyde Space third generation (3G ) electrical power system (EPS) manages electrical power generation, storage and management and commonly makes up one-third of total spacecraft mass.

Clyde Space solar panels The Clyde Space solar panels utilize the photoelectric effect to generate electrical current. Solar cells, are made out of thin wafers of semiconductors that produce electric current when exposed to light. Their primary function is to charge the battery and power the electrical loads through the EPS.

Clyde Space integrated battery The Clyde Space integrated battery is used for energy storage and is equipped with an internal heater. It Is a lithium-based battery which is commonly used in portable electronic devices because of their ability to recharge, their low weight, and their high energy capacity. Commonly used in CubeSat missions; Clyde Space integrated batteries are generally connected to a primary energy provider such as a solar array, are able to provide power on demand, and recharge on their own.

CubeSats Constellations Currently in Orbit (3D)

CubeSats Constellations Currently in Orbit (2D)

Orbital Drag Simulations Direct Simulation Monte Carlo (DSMC) Thermospheric variations cause premature deorbit Highly rarefied above 150km Free molecular, nearly collisionless flow (mean free path ~ 20-40km) Navier-Stokes Equations do not provide good solutions Monte Carlo Simulations are used to stochastically solve the Boltzmann equation

Orbital Drag Simulations - Issues Mean Free Path calculations are not developed Exponential signs are incorrect for some values Large simulation times for fully developed solutions Little to compare to for LEO using DSMC

Future Work FEA Analysis Build Prototype Testing at NASA