HS-1 Subsystems Info

Attitude Determination

The ADCS uses an array of sensors, including an Inertial Measurement Unit (IMU), a sun sensor, and a magnetometer to determine the current kinematic state of the satellite. This is used in combination with physical models and the previously known kinematic state to produce a precise pointing vector in an algorithm called a Kalman filter.

Attitude Control

Knowing the satellite's pointing direction, the ADCS will then decide the optimal direction to point the satellite. After computing this direction, the ADCS computers will send commands to the satellite's actuators, the magnetorquers. By passing current through an electromagnet, we can generate a magnetic dipole in the satellite, which will exert a torque against Earth's magnetic field, allowing us to aim the body of the satellite.

The CDH team is responsible for most software and command definitions, whether it be the code the flies with the satellite on orbit, or the code that controls our operations center on the ground.

On HS-1, we use a CAN bus is used to interconnect a distributed system of 9 MSP430 MCUs and 2 Raspberry Pi. Each of the MCU's has SPI/UART/ADC/I2C exposed for special functions, from monitoring battery temperature to driving the magnetorquers.

COM1

The COM-1 Subsystem is responsible to provide a reliable relay link with the spacecraft

The primary components on the spacecraft:

• 1. Deployable ISIS UHF/VHF dipole antennas

  2. AMSAT Linear Transponder

The primary components on the ground station:

• 1. Circular polarized UHF/VHF antennas

  2. G5500 rotator

  3. Advanced Receiver LNA

  4. IC9100 and FunCube Dongles

  5. SatPC32 for tracking and Dopplar control

  6. FoxTelemetry for decoding

COM2

COM2 is a K/Ka-band communication system developed at UW.

Its aim is to enable university CubeSat's to access high performance communication systems without the steep price tag.

The primary components are:

• 1. Deployable high-gain reflectarray

     1. • 100x circularly polarized elements

  2. RF Front End

     1. • frequency up-conversion

        • solid-state power amplification

  3. Baseband

     1. • GNU Radio operation

The EPS design was driven by powering the 50W thruster module as well as the 24GHz communication system. The solar array provides up to 18W, and the energy is stored in 4x 18650 cells. Centralized power distribution and monitoring is implemented across 8 power domains.

EPS is broken up into 3 boards:

• Generation board: measures solar panel voltages and currents, and converts panel voltage to bus voltage

• Distribution board: provides power toggling and current monitoring for all power domains

• Battery assembly: tracks battery state, balances cells, and controls battery heaters

The Structures team is responsible for the design of a robust, vibration resistant chassis and for the development of deployable hardware

The Thermal subsystem works to ensure satellite components operate within allowable temperature ranges