Auxiliary/Maintenance Systems
Attitude Determination and Control Subsystems
In order to keep each CubeSat oriented with the camera aimed towards the Earth, an attitude control system was implemented in the form of a set of orthogonal magnetorquers. These are active electromagnetic devices that can align the satellite with respect to the Earth's own magnetic field lines; by using 3 such devices, each oriented along one of the 3 spatial axes, the satellite can slowly orient itself in nearly any position. Two of these are located in a pair of the solar panels, providing the "X" and "Y" axes, while a third independent magnetorquer is attached along the length of the satellite chassis to provide a "Z" axis.
Magnetorquers
http://www.clyde-space.com/cubesat_shop/adcs/mtq_rods/215_z-axis-magnetorquer
In order to control these devices, an Attitude Determination and Control board, separate from the main CPU board, constantly monitors the satellite's orientation using an array of onboard magnetomoters, and adjusts power to the magnetorquers to compensate. Additionally, a GPS daughterboard is included to aid in ground station tracking and in adjusting JPEG compression levels for specific areas according to customer specification.
ADCS and GPS
http://www.clyde-space.com/cubesat_shop/adcs/adcs_board/299_cubesat-adcs-module
http://www.clyde-space.com/cubesat_shop/adcs/adcs_board/330_gps-daughter-board-option
Station-keeping
According to Mars Space, inc., the average lifetime for a 3U cubesat at 450 km is approximately 4 years and 2 months, after which reentry is imminent. By adding a Pulsed Plasma Thruster, at an average power cost of 0.04 Watts and weight cost of 280 grams, the satellite's orbital lifetime can be extended up to 6 years. This is a crucial improvement, because it reduces the number of launches per 10 years from 3 to 2. [1]
PPT Module
http://www.clyde-space.com/cubesat_shop/propulsion/303_cubesat-pulse-plasma-thruster
CPU and Motherboard
The CPU and motherboard are designed by Pumpkin. The mainboard is designed with a modular system in mind; while Pumpkin provides pluggable packages for common processors such as PIC24, Pumpkin does provide specs to enable users to design their own modules in order to support other processors. The board itself provides breakout connections and buses (such as I2C) to the processor. For CPU, our choice was the commonly available PIC24 24-bit microcontroller. Together, this system will manage the and command all the major subsystems of the satellite.
Pumpkin Board
http://www.clyde-space.com/cubesat_shop/obdh/pumpkin_cubesat_obc/pumpkin_motherboard/146_motherboard
http://www.clyde-space.com/cubesat_shop/obdh/pluggable_processor_modules_pumpkin_motherboard/pic/272_pluggable-processor-module-d1-ppm-d1-with-microchip-pic24fj256ga110-64mbit-serial-flash-memory
[1] http://www.mars-space.co.uk/projects/pptcup
In order to keep each CubeSat oriented with the camera aimed towards the Earth, an attitude control system was implemented in the form of a set of orthogonal magnetorquers. These are active electromagnetic devices that can align the satellite with respect to the Earth's own magnetic field lines; by using 3 such devices, each oriented along one of the 3 spatial axes, the satellite can slowly orient itself in nearly any position. Two of these are located in a pair of the solar panels, providing the "X" and "Y" axes, while a third independent magnetorquer is attached along the length of the satellite chassis to provide a "Z" axis.
Magnetorquers
http://www.clyde-space.com/cubesat_shop/adcs/mtq_rods/215_z-axis-magnetorquer
In order to control these devices, an Attitude Determination and Control board, separate from the main CPU board, constantly monitors the satellite's orientation using an array of onboard magnetomoters, and adjusts power to the magnetorquers to compensate. Additionally, a GPS daughterboard is included to aid in ground station tracking and in adjusting JPEG compression levels for specific areas according to customer specification.
ADCS and GPS
http://www.clyde-space.com/cubesat_shop/adcs/adcs_board/299_cubesat-adcs-module
http://www.clyde-space.com/cubesat_shop/adcs/adcs_board/330_gps-daughter-board-option
Station-keeping
According to Mars Space, inc., the average lifetime for a 3U cubesat at 450 km is approximately 4 years and 2 months, after which reentry is imminent. By adding a Pulsed Plasma Thruster, at an average power cost of 0.04 Watts and weight cost of 280 grams, the satellite's orbital lifetime can be extended up to 6 years. This is a crucial improvement, because it reduces the number of launches per 10 years from 3 to 2. [1]
PPT Module
http://www.clyde-space.com/cubesat_shop/propulsion/303_cubesat-pulse-plasma-thruster
CPU and Motherboard
The CPU and motherboard are designed by Pumpkin. The mainboard is designed with a modular system in mind; while Pumpkin provides pluggable packages for common processors such as PIC24, Pumpkin does provide specs to enable users to design their own modules in order to support other processors. The board itself provides breakout connections and buses (such as I2C) to the processor. For CPU, our choice was the commonly available PIC24 24-bit microcontroller. Together, this system will manage the and command all the major subsystems of the satellite.
Pumpkin Board
http://www.clyde-space.com/cubesat_shop/obdh/pumpkin_cubesat_obc/pumpkin_motherboard/146_motherboard
http://www.clyde-space.com/cubesat_shop/obdh/pluggable_processor_modules_pumpkin_motherboard/pic/272_pluggable-processor-module-d1-ppm-d1-with-microchip-pic24fj256ga110-64mbit-serial-flash-memory
[1] http://www.mars-space.co.uk/projects/pptcup