Modular Nanosatellites as Amateur Radio Communication Platforms Gus Moore; Todd Kerner, KB2BCT; Amish Parashar, KE6EZM Funded by the New Hampshire Space Grant Consortium

Project Concept

• Modularity by Design • A functional bus module providing Power, Control, Communications • Platform for Single-Purpose Research • Compatibility with other University Programs • Incremental Development

Evolution of DARTSAT

“Student Initiated, Student Designed, Faculty Mentored” • Conceived Fall ‘99 as Amateur Radio Communications Satellite • Desired Experimental Capabilities “A Modular Approach to Space Access”

CubeSat Program

• Stanford / CalPoly SLO providing opportunity for Thayer School’s Satellite Design Program Establishes standards for design

DARTSAT Specifications

• 10 cm cube pre-release, < 1 kg • 1 year functional life • Amateur radio communication • < $10,000 System Bus • Capability to support a wide variety of experiments at any time

Modularity

Low Earth Orbit

Functional Block Diagram

DARTSAT Functions

• CPU – FM repeater (J-mode) – DTMF control – Analog Measurements – Morse Code ID • Data Acquisition – Temperature – Solar Cell Power – Battery Status – Magnetic Fields (Orientation)

Power

• Batteries – 4.8V, 2A NiCds • Solar Panels – 6.0V, 200 mA • Distribution – Passive Diodes

Radio Specifications

• Receiver: 144 MHz uplink – Motorola MC13136 – FM, 1 uV sensitivity, 5 kHz bandwidth – 3.8 VDC, 50 mA Operation • Transmitter: 440 MHz download – Motorola MC13176, RF2117 Amplifier – FM, 125 to 500 mW RF Output, 5 kHz BW – 3.8 VDC, 500 mA max operation

Antennas

•Perpendicular Dipoles for Transmitter & Receiver •0 dB Gain •Omni directional since satellite is not stabilized •Using circularly polarized, high gain antennas on ground •Antenna deployment once space borne

Unique Challenges

• Wide Temperature Oscillation -40 to +50 C • Limited Power • Physically small package – SMT all parts if necessary • Extreme Vibrations  stabilized • Radiation Issues  circuitry high spin rates  not little mass protecting the

Testing DARTSAT

• Conducted at Lockheed / Sanders – Temperature – Vacuum – Vibration – Electrical Interference – Charging Case – Radiation Hardness

DARTSAT Status

• Satellite Design Complete – Radios – Mechanical – Power – Control • Prototype complete – January 2001 • Testing – February 2001 • Flight unit – March 2001

Conclusions

• New student program, inaugural to Dartmouth Space Programs • Provides a link between Amateur Radio and Academic Communities • Future – Standardized Bus  Plug and Play Science Experiments – Constellations  Low cost, large area communications

Recognition

• New Hampshire Space Grant Consortium • Lockheed Sanders • Stanford / CalPoly • Apple Computer • Thayer School and Dartmouth College Alumni