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Dan, Nick, and Silverio in the SPACE HAUC laboratory

SPACE HAUC Subsystems

Silverio demonstrating use of the gyroscope in conjunction with the Intel Edison processor Photo by Becky Campelli

Attitude Determination and Control System

The attitude of a satellite is its orientation in space. To determine the current attitude, magnetometers measure the intensity and direction of Earth's geomagnetic field while sun sensors measure the intensity of sunlight. By sending current to three separate electromagnetic coils (commonly known as magnetic torquers), we can command the satellite to a desired orientation.

Antennas

A patch antenna is a flat, low-profile patch of conductive metal etched onto a dielectric substrate, or a nonconductive, insulating material. An omnidirectional antenna radiates power in all directions, but an array of patch antennas can radiate power with more selective directivity when phased (see Beam Steering).

Beam Steering: the max electric field per unit radian for Photo by Will Chambers

BEAM STEERING

The directivity of the patch antenna array's signal is possible through a principle called beam steering, or beam forming. Instead of commanding all patch antennas to radiate simultaneously, the phase of each antenna element is precisely controlled using a device called a phase shifter. This causes the signal from each element to be produced at a slightly different time. The resultant mixing of signals in constructive and destructive interference "steers" the signal in the chosen direction.

TELEMETRY

The data collected by the satellite is transmitted via the telemetry subsystem. Data is embedded into a signal (a process called modulation) and this signal is sent back to Earth through the phased antenna array with a transmitter. Signals are also received from Earth through the receiver, demodulated, and then sent to the central processor.

Intel Edison - Command and Data Handling Photo by Becky Campelli

COMMAND AND DATA HANDLING

The "brain" of the satellite is the processor, which connects all other subsystems of the CubeSat to manage the flow of data. This flow includes commands sent to the satellite by controllers on Earth, health and status of subsystems or "housekeeping" data, and images captured by the camera to be sent back down to Earth.

GROUND STATION

A ground station is composed of the software and hardware here on Earth that will allow us to communicate with the satellite once it is in orbit. A roof-mounted television antenna is one such example of a simple ground station which could only receive telemetry.

POWER

Several CubeSat components need power to be operational. The most common method of power generation in orbit is the use of solar panels. The generated power must then be managed and distributed throughout the satellite.

Rendering of an early concept for the CubeSat frame

STRUCTURES

All the CubeSat components will be housed in the structure, which must be strong enough to ensure that the satellite safely reaches orbit. There are several methods to reach low Earth orbit, but the most common method for CubeSats is to piggyback on another rocket as a secondary payload. During launch, rockets are subject to very large forces and vibrations.

THERMAL CONTROL

On Earth, we are protected by an atmosphere. In low Earth orbit, the atmosphere is below us and that protection is no longer present. Satellites are subject to intense thermal radiation, such as direct solar energy, albedo (solar energy reflected off the Earth), and infrared energy produced by the Earth itself. Keeping the CubeSat and its components within operational temperature ranges is achieved by maintaining a thermal balance throughout the satellite.