Cubesat Comms Design Page
AX.25 Packet Transponder
US Naval Academy Satellite Lab,
Bob Bruninga, WB4APR
Student Experiments using Amateur Radio Commuinications Cubesats This page is an attempt to show how simple it is to build a Cubesat sized Comms payload using off-the-shelf AX.25 Packet Radio modules. With nothing more than a battery, some solar panels and a reset circuit, this can provide the basis for the design of many cubesats with a variety of primary missions.
The power point pages below were prepared in 2009, and represented the Naval Academy student comms satellites up through about 2007. Then we worked for several years on our next mission that was not launched until 2015 in the form of PSAT or NO-84.
Suffice it to say, that during this time we have reduced the size of the comms payload by a factor of 18 to 1. Although it will take some time to update this presentation to our current state of the art using our new SATT4 comms board, this presentation (as it is) will give you an idea of how we use Ham radio in space. In the meantime, you can view these web page links below to see how we are using them in 2015 through 2017:
PCsat-1 in orbit since 2001 semi-operational
ARISS on the ISS since 2007
Psat Operational since May 2015
BRICSAT-1 launched with PSAT, but insufficient power budget
QIKcom-1 IS ON ISS, but activation blocked by FCC SNAFU
QIKcom-2 with APRStt/Voice for launch Summer 2016
PSAT-2 With APRStt/Voice and PSK31 for launch spring of 2017
BRICSAT-2 APRS digi and thruster experiment for launch spring of 2017
ASTARS missions: Prior APRS missions on other spacecraft, ISS, Shuttle and MIR
ALL are Welcome! We need more of thse comm boards in space to help support the constellation of cummunications data relay cubesats for relaying student experimental and remote sensor data. These data transponders provide a "force-multiplier" because they allow for a multiplication of student access to space for their own aerospace and other science research projects which can use this constellation in the gathering of real-time data from experiments anywhere on earth.