Satellite Attitude Determination, Communication, and Control with AI

Orbiting the Earth alongside large objects like the Hubble Telescope or the ISS, small satellites, known as CubeSats, are flown for educational or experimental purposes and are about the size of a shoebox. Two integral components of these small satellites are the ADCS, the system that controls the satellite’s position, and the communication module, the system that sends and receives information. Integrated, commercial versions of these systems are generally cost-prohibitive for a CubeSat application. The goal is to instead use individual components to make a cheaper control system and to create a board that will apply existing technology to the CubeSat scale. The solutions we create will lead to better control of the satellite and increased ability to send information to ground. This larger rate of data transfer allows for more complex functionality, like running a Star Tracker, to occur.

=Problem Definition= Team Tardigrades' first primary goal will be to complete the development of the hardware and software for the Iridium 9523 Satellite Modem and its associated carrier module. This year will be the conclusive year on the project as it was started in the Fall of 2018 by the Capstone research team SCUBEE. The Iridium 9523 is capable of communications in the form of Short Burst Data (SBD) and stream network (RUDICS) modes. It has current use in NASA’s REBR program and The ESA’s QARMAN satellite. By completing this project, the effort put into the 9523 Satellite and its carrier will significantly improve the communication of smaller satellites in use. The design for this project is a fraction of the cost and complexity of standard satellite communication through radio modems. With progress already made on the project through the design team SCUBEE and team FIRE, a final flight-ready unit is a deliverable at the end of the project. If the project can uphold the deadline, the satellite could see a flight opportunity in 2021.

This portion of the project can be broken down into 3 main components:  The software necessary to provide encrypted communication from the ground server to the satellite. Managing firmware development between the dev board and the SAMD51. Designing a Radio Frequency power boost converter. 

The ACDS sub-team has the complementary goal of developing a modular Attitude Determination and Control system for a 6U satellite. The focus of this group will be to develop a unit with lower cost and lead time compared to a commercial ACDS system. The final ACDS system should have comparable pointing abilities to commercial models, utilizing a combination of instruments (flywheels, magnetorquers) for attitude control and attitude determination (magnetometers, sun sensors, and IMUs). The group is expected to perform component selection, prototyping, and testing of individual components, but not the combined system.

This portion of the project can be broken down into 4 main components:  Consult materials against radiation shielding Develop control and firmware needed Development of electronic components and firmware for Sun Sensors, Magnetometers, and IMU Consult components to research and manufacture including torque rods, PCB Magnetorquers and Reaction Wheels</li> </ul>

Background
The Nano Orbital Workshop (NOW) department at NASA Ames focuses on finding cost-efficient solutions to small satellite development. This department researches cutting-edge development in computer science and engineering to create novel low-cost technology. The NOW Group has partnered with the University of Idaho's research initiative for many years to introduce students to the innovations in satellite development. These interest groups can complete educational satellites and see demonstrations through flight. With the recent launch of the TES-10 satellite, the NOW group is focusing on the use of GPU processors in space. Some of the current interests in GPU processors can be seen in its ability for autonomous navigation, onboard network communications for data transfer, and guided reentry via Exo-Brake technology. This year, the team will be focusing on the continuation of the use of the TFLOP GPU processors and begin the design and prototype for a new electromechanical satellite system.



Guided Parafoil System (GPS)</li> A team in 2014 had completed the foundation of the project by creating the guided parafoil system that can move the returning payload to a pre-determined GPS location on its return.

SCUBEE: Space Communication Utilizing Backbone Existing Networks Fall 2018 - Spring 2019</li> Team SCUBEE had created a carrier module able to control and house the Iridium 9523 modem to integrate into the cube satellite. Team SCUBEE had also created the initial code for communicating over the Iridium satellite network using the Iridium 9523 via short bust data (SBD) messages.

FIRE: Firebox Iridium Re-Entry Fall 2019 - Spring 2020</li> Team fire built off of team SCUBEE's work by creating a building off of the communication system with the Iridium 9523, added the Canon BP-955 as a power source with a fireproof containment unit. Team FIRE had also re-designed the carrier module to host the Iridium 9523 in a more compact way. </ul>

Iridium 9523

 * Software / Firmware


 * Software for encrypted communication from the ground server to the Iridium 9523</li>
 * Updated firmware for the switch between the SAMD21 to the SAMD51</li>
 * Firmware for the initialization of power between the SAMD51 and the Iridium 9523</li>
 * Software to handle unexpected technology behavior</li>
 * Software for a ground server to communicate with the Iridium 9523</li>
 * Software to parse and analyze decrypted information at the ground server and on the Cube Satellite</li>

</ul>
 * Development Board


 * An updated schematic for the development board </li>
 * A Redesign of the Boost Converter </li>
 * Hookup the Development Board to the SAMD51</li>

</ul>

ADCS

 * Research


 * <li>Create a cost benefit analysis for Electrical Engineering components: sun sensors (coarse & fine), magnetometers, Inertial measurement unit (IMU)</li>
 * <li> Create a cost benefit analysis for Mechanical Engineering components: Torque Rods, Magnetorquers, Reaction Wheels </li>
 * <li> Research the best control device and firmware needed to control the selected hardware </li>

</ul>


 * Select Components

<ul>
 * <li> Select the best choice for satellite components and prepare for the assembly of a prototype </li>
 * <li> Select the best material for ware conditions with predictions on longevity </li>
 * <li> Select the best material for radiation shielding </li>

</ul>

AI in the Sky

 * Software

<ul>
 * <li>Research and develop an experiment to demonstrate machine learning on an active space craft</li>
 * <li>Develop software to determine the radiation effects of a running GPU</li>
 * <li>Develop a low bandwidth slow-paced interactive program to demonstrate GPU abilities</li>
 * <li> Design a better carrier for the Nvidia GPU </li>

</ul>

Specifications
The requirements as outlined by our client are shown below:

Iridium 9523 Main Requirements

 * Design and test firmware and ground software for SAMD51-based 9523 board
 * Need to update the SAMD1 board developed by SCUBEE to a SAMD51
 * Send schematic to our client for an updated development board with focus on updating the boost converter
 * Receive board back from client for final Development and testing

<ul> </ul>

ADCS Main Requirements

 * Research and select the ADCS components
 * Design a driver topology to enable control system growth

<ul> </ul>

AI in the Sky Main Requirements

 * Research and develop an experiment to demonstrate useful machine learning on an active spacecraft
 * Develop software to determine the radiation effects on a running GPU
 * Develop a low bandwidth slow-paced interactive program to demonstrate GPU abilities
 * Design a better carrier for the Nvidia GPU

<ul> </ul>

=Design Considerations=

Ground Server

 * The Hardware

The ground server was first considered to be located on the University of Idaho Network. When our team communicated that we needed an outward facing server on the network, they brought up multiple complications and documents that we would take longer than our time on this project. Because of this drawback, we setup our ground server through digital ocean as it provides our team an internet facing server with a static IP address.


 * The Software

The ground server software was straight forward. Our team understood we needed a simple socket connection that could receive communication on a binded port, but we initially struggled with implementing encryption with pre created code used on the Satellite RTOS firmware. After communicating with the team, we decided on using the wolfcrypt library to implement AES256 encryption across the internet.

Low Cost IMU Options

 * 9-Axis Inertial Navigation Module for Arduino
 * $32
 * Operating Voltage rang: 3-5 V
 * Gyroscopes range: ± 250, 500, 1000, 2000 ° / s
 * Acceleration range: ± 2 ± 4 ± 8 ± 16g
 * Field range: ± 4800uT


 * Sparkfun ICM-20948
 * $17
 * Operating Voltage rang: 1.71-3.6 V
 * Gyroscopes range: ± 250, 500, 1000, 2000 dps
 * Acceleration range: ± 2 ± 4 ± 8 ± 16g
 * Field range: ± 4900uT
 * Includes magnetometer features


 * Adafruit ICM-20948 9-DoF
 * $15
 * Operating Voltage: 1.8-5V
 * Gyroscopes range: ± 250, 500, 1000, 2000 dps
 * Acceleration range: ± 2 ± 4 ± 8 ± 16g
 * Field range: ± 4900uT


 * X-Nucleo-IKS01A2
 * $20
 * Gyroscopes range: ±125/±245/±500/±1000/±2000 dps
 * Acceleration range: ± 2 ± 4 ± 8 ± 16g
 * Magnetometer: ±50 gauss

DEV Board Schematic Component Information

 * SAMD32
 * $32

=Project Learning=

ADCS
In the project we have learned how to effectively manage a project budget as well as how to properly research different components. We’re trying to understand how components work so that we can choose an adequate but low-cost option. Grace Rosenvall needed to do research and calculations to understand how reaction wheels worked with regards to angular momentum and to ensure the feasibility of my design. Andrew Pilchard completed research on the selection for RF converters. With all of the teams selections we had to simulate them in the circuits to see if they could work with our design specifications.

9523
Over the past 10 months, the 9523 subgroup has overcame multiple challenges in developing the firmware and communication back to the ground server.

=Final Design=

ACDS

 * Reaction Wheel:
 * Stats:


 * Moment of Inertia = 26122.27 g*mm^2
 * Diameter = 58mm
 * Thickness = 11mm
 * Improvement from old stats:


 * Moment of Inertia: 11029.21 g*mm^2
 * Diameter = 48mm
 * Thickness = 9mm

=Validation=

Traceability Matrix
Example test: Simulating an overheating condition in software and verifying the device shuts off correctly. Program Protection Standards
 * We will create a Requirement Traceability Matrix to validate that all requirements given to us by NASA are checked via test cases such that no functionality is unchecked during Software testing and system testing.
 * The traceability matrix would cover the following standards:
 * 4.1.1 - Command Stack Protection
 * Commands to and from the ground server must be encrypted.
 * Must comply with the Federal Information Processing Standard (FIPS) 140
 * Refers to another document for encryption standards
 * 4.1.2 Backup Command Link Protection
 * A backup command process should be created that overrides command authority in an anomalous condition. This command authority should be encrypted form of authentication.
 * 4.1.3 Command Link Critical Program/Project Information (CPI)
 * encryption, authentication, and CPI protection of hardware commands, key-handling, and bit patterns of critical patterns.
 * 4.2 Ensure Positioning, Navigation, and Timing (PNT) Resilience
 * Position, Navigation, and Timing information should be protected as well as the communication path via secure protocols.
 * 4.3.1 Interference Reporting
 * We should report unexplained interference to SAPP or other notifying organizations
 * 4.3.2 Interference Reporting Training
 * Proficiency training to make sure we can detect interference

Flywheel Testing
​Controls System Testing​
 * Manufacturing a test stand to mount the flywheel to demonstrate its ability to correct to center when rotated by external force​
 * Manufacture and solder board that is capable of accurately detecting movement, spinning motor in the direction and speed indicated by a command sent to the system, and supplying correct voltage to all components of board.​

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=Team Members=

=Additional Documentation=

Presentations