University of Illinois - ION Cubesat Project

Illinois Tiny Satellite Initiative		University of Illinois @ Urbana-Champaign
ITSI	Home Welcome Latest News K-6 Webpage Subscribe Course Contacts Structure Payload Attitude Ctrl Power Comm Software Testing Media Photos/Video Articles ION Facts J-Track Technical ION Dashbrd Beacons Publications	UIUC

Structure

Satellite Components

Component	Placement Justification
Photometer	Positioned at the bottom of the satellite, in order to face the earth and take atmospheric readings.
Photometer Shutdown Diodes	Located next to the photometer facing in the same direction.
Camera	Positioned at the bottom of the satellite, in order to constantly face the and earth and take pictures of it.
Torque Coils	One torque coil is mounted perpendicular to each axis for proper attitude control.
Batteries	The batteries are the heaviest and largest object onboard, as such they are located on one side as close to the geometrical center as possible, minimizing both CG problems and the occupied space.
Antenna	Located at the top of the satellite, which maximizes its deployable length.
Thruster Power Processing Unit	This unit requires vibrational isolation and is mounted on four legs, this required a firm mount on the bottom of the satellite.
Thrusters	Four thrusters are located on opposite sides of the satellite at opposite corners to maximize control ability.
Separation Springs	The feet are the only part of CubeSats that contact other CubeSats, so springs are located there to help separate the satellites when deployed on orbit.
Switches	Switches are also located on the feet and will be depressed in the PPOD, upon deployment they will open up and allow the satellite to power up.
Pull Pin	The pull pin is located in the middle of the satellite, so that it is inline with one of the windows on the PPOD. This is a redundant switch that cuts power, and can be removed via the window before launch.
Power Board & Attitude Control Board	These boards are mounted together horizontally to minimize the occupied space.
SID Processor	Centrally located to minimize wire lengths.
Power Point Tracking Board	This board was sized to fit next to the antenna board to maximize the space at the top of the satellite.
Radio	The radio board is mounted in the middle of the satellite as close to the radio board as possible to minimize wire lengths.
Terminal Node Controller	This board was located on an adjacent face to radio board and the SID Processor to minimize wire lengths between the three boards.

Thermal Control

In order for the mission to succeed, the satellite must survive in the harsh space environment. The temperature in space ranges from 120° C in direct sunlight to -100° C in Earth's shadow making it one of the harshest environments imaginable. Unfortunately, the satellite's systems will not operate within this temperature range, so its thermal environment must be controlled. While the temperatures in space are brutal themselves, the rapid temperature fluctuations will also create problems. During each orbit of the Earth, the spacecraft may suffer both temperature extremes.

Three stages of the mission affect the thermal control system (TCS): the launch, the orbital placement by the launch vehicle, and the final orbit. The launch vehicle will provide a temperature adequate for the first two stages of this mission. The final orbit determines which TCS must be used for each component. Each component has its own operational temperature range. Even when not operational, it is not advised to fall outside of the operational temperature range for an extended amount of time.