Modular Nanosatellites as Amateur Radio Communication Platforms

Funded by the

New Hampshire Space Grant Consortium

Gus Moore; Todd Kerner, KB2BCT; Amish Parashar, KE6EZM

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 high spin rates not stabilized

• Radiation Issues little mass protecting the circuitry

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