Advanced COM Device

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The ACOM team is working to create a faster more reliable communication system to be deployed on a sub-orbital balloon, as well as prototyping more efficient enclosures.

Team Name ACOM
Duration Spring 2017 - Fall 2018
Faculty Adviser Dr. Feng Li
Duration Fall 2016 - Spring 2017
Team Members
  • Byron Bowles
  • Hanna Salian
  • Mellisa Dow
  • Peter Fetros
  • Trevor Morse
  • Tysen Buster
GitHub Page

Problem Definition[edit]


In the past NASA AMES has used Iridium Modems to establish communication between flight experiments and ground stations in order to facilitate the transfer of data. However in previous experiments the equipment used was based on the 9602 Iridium Modem which only supports short bursts data communication. In order to make missions more efficient they are seeking a way to increase the amount of data that can be received during a single missions.


  • Complete 9523 Iridium Modem Data Streaming System.
  • 3D printed and Fully Tested Tube Deployed Reentry Vehicle prototypes.
  • Zigbee Mesh Network Prototype.



  • 9523 Iridium Modem Development Board
    • Breaks out all 9523 functionality
    • Integrate Zigbee Wireless module


  • 9523 Iridium Modem interface Library
    • Interface with 9523 Iridium Modem
    • Data streaming capability
    • Unit Test
  • Zigbee interface library
    • TBD
  • Code Documentation


  • Create CAD designs of components
    • Space efficient design for modem assembly
    • Efficient strut deployment method
    • Fit into a 8”x8”x12” rectangular cavity
    • Reusable
  • 3D print prototypes
  • Deploy from High altitude balloon for testing

Electrical Design[edit]

The diagram below shows the high level overview of the interconnected devices found in the system, This is an example of how a single system would be connected within the TDRV.


The below diagram is an example of our altered RS232 connection protocol. While the black-box device we are using to interface with the Iridium Modem has the ability to utilize the normal RS232 standard, we must use a slightly altered version that uses less wires due to the limitations of our system.

2018 ACOM RS232Setup.png

Software Design[edit]

The software we're writing for this project will be running on top of an Arch Linux distribution. This platform was chosen because it allowed us to write operating-system-agnostic software so that, if the hardware requirements changed in the future, would make it easier for teams to change the type of hardware to something else as long as a Linux system could be loaded onto it.

Below is flow diagram that gives the overview of how our software will interface with the modem through the sending of AT commands. 2018 ACOM MODEM SOFTWARE DESIGN FLOW.PNG

Mechanical Design[edit]

The Mechanical Engineering focus will be to take the above parts and assemblies and redesign them to accomplish several goals.

  • Fit the iridium modem and associated hardware efficiently inside.
  • Find an efficient way to deploy the struts in order to deploy the wing.

A prototype will be created using 3D printing technologies for design validation. It will then be tested in flight on a high altitude balloon.

The final design while folded, has to fit into a 8”x8”x12” rectangular cavity and should be reusable.

Part Description
2017 ACOM TDRVFULL.png Figure 1: Original TDRV Fully assembled and open. This is what the TDRV would look like if no modifications where made.

This is what the final assembly will be compared to.

2017 ACOM TDRVEXPLODED.png TDRV Exploded view of assemble
2017 ACOM STRUTRING.png Strut Ring connecting arms to assemble. It is critical that this piece is high heat tolerant in final design (future project)
2017 ACOM MAINBODY.png The above image shows the changes made to the main body. First and it was made a ½ inch wider in diameter. This was done because it would have been impossible to fit a Raspberry Pi 3 Model B within the original body. Another reason it was done is because the original documents included a model that was 3 inches in diameter, so this seemed like a reasonable change. Another Change made to the main body was making the upper portion of the inner cavity rounded out to make more room for the parts. The bottom portion of the cavity was kept the same because this is where the Go Pro is placed, and it is kept at a tight fit.
2017 ACOM FULLASSEMBLY.png Final assembly Exploded Sub-Assemblies 00 (Left), 01 (Center), and 02 (Right). They are named Main Body Sub-Assembly, Center Holder Sub-Assembly, and Strut Ring Sub-Assembly, respectively.
2018 ACOM FLUIDTESTINGMODEL.png ANSYS Fluent testing model created in order to get a better understanding of how the model will behave in real world testing scenarios.

Digital File Repository[edit]

Xbee Code

Iridium Modem Code

Server Code

Team Information[edit]


Team members left to right
Member Biography Discipline
Hanna Salian I am a Computer Science major and Mathematics minor. I enjoy reading, writing, working on digital art, and learning mixed martial arts in my free time. Computer Science
Mellisa Dow I am majoring in Electrical Engineering with an interest in electromagnetics/antennas/microwaves. I also enjoy playing violin, swimming, walking around, and visiting the humane society. Electrical Engineer
Peter Fetros I'm a Computer Science and Computer Engineering double major with a passion for operating systems, embedded systems/software and Linux. Computer Engineer
Trevor Morse I am majoring in Computer Science with a minor in Mathematics. I enjoy exploring the fields of AI and ML as well as playing sports with friends. Computer Science
Byron Bowles My name is Byron Bowles I am a Mechanical Engineering Senior at the University of Idaho and enjoy 3d modeling and mechanics of material classes. Originally from Potlatch, Idaho, I enjoy skiing, tinkering, reading, and travelling with my wife and 2 dogs. Mechanical Engineer
Tysen Buster My name is Tysen and I'm majoring in mechanical engineering. I enjoy camping in the summer and snowboarding in the winter. Mechanical Engineer