Spacecraft must be lightweight yet robust enough to navigate both through atmospheric layers and space without losing speed or efficiency. Their components must also withstand both very high and very low temperatures while fuel tanks must contain liquids with extreme pressures such as cryogenic liquids.
Aluminum and titanium are two of the primary metals utilized for spacecraft components, though other materials such as fiberglass and Kevlar (the same tough fabric found in bulletproof vests) may also be employed to shield.
Structural Subsystem
The structure subsystem ensures the physical integrity of a spacecraft. It must support components during integration, testing, free fall flight and operation of propulsion systems as well as antennae, booms and other devices onboard the spacecraft.
Communication subsystem components include radio transmitters and receivers, signal processing units for modulation/demodulation operations and data encoding/decoding operations, as well as communication channels between mission operators and ground control. Telemetry data are sent back through these channels while missions operators receive instructions via radio transmitter/receiver pairing.
Telecommunications subsystems connect spacecraft with Earth through communication satellites and mission control on the ground. It often plays an integral part of their missions, acting as the main interface between spacecraft and mission control. Telecommunications systems may feature high gain antennas capable of transmitting high rates over long distances.
Payload Subsystem
The payload subsystem comprises the spacecraft’s primary sensors or instruments used for collecting data, transmitting that information back to its home satellite and relaying this information for analysis by other parts of its mission.
This subsystem manages on-board computers and performs various other functions such as system housekeeping, component telemetry data management and failure isolation and recovery. Using space qualified radiation-hardened components.
Navigation payloads are essential components of many NewSpace missions and use radio signals to precisely locate satellites in space. Navigation sensors may either be active or passive sensors – active sensors fire down towards Earth to collect surface characteristics and atmospheric patterns while passive ones collect reflected signals back from it. On STRATHcube’s advanced design telecommunications subsystem is equipped with a PMAD capable of supplying power as well as signal processing capabilities for power delivery and signal processing capabilities.
Thermal Control Subsystem
The TCS ensures that spacecraft operate within specific temperature limits, protecting its electronics and mechanical systems. Its task involves overseeing heat generation, dissipation and distribution.
TCS is necessary because the equipment onboard a spacecraft must meet specific temperature stability requirements to function optimally; otherwise it could become permanently damaged and lose functionality.
The TCS regulates the thermal environment by controlling radiators, internal insulation, rear-surface mirrors and passive radiators. It selects materials with absorptive, emissive and reflective properties for radiator surfaces as well as multilayer insulation blankets (MLI) with thermal control coatings to regulate their conductivity properties. Furthermore, mechanical louvers and shutters regulate how much heat radiates out into deep space.
Electrical Subsystem
The Power Subsystem generates, stores and distributes electrical energy throughout a spacecraft. Solar panels and batteries serve as sources of power while power regulators ensure each onboard component receives their appropriate voltage/current levels.
The Command and Data Subsystem receives commands sent from Earth to the satellite, which are executed according to time intervals determined by its spacecraft clock. Additionally, engineers on earth use this telemetry data for monitoring purposes in order to assess its health status.
This system regulates the satellite’s movement in space. It employs engines or thrusters that release fuel for thrust production, as well as systems to calculate how much thrust will be necessary for maneuvers such as orbit insertion, station-keeping or end-of-life disposal. Furthermore, avionics enable communication with ground control and launch vehicles.
Navigation Subsystem
The navigation subsystem or guidance and control subsystem (GNC) identifies the spacecraft’s position and velocity within space. This is typically accomplished using atomic clocks to measure distance from satellite signals to spacecraft before deriving coordinates x, y and z based on these measurements.
GNC also houses a communication system designed to relay science data back to Earth via radio waves – known as telescience data – as well as engineering/housekeeping information known as telemetry; the latter can include switch positions or subsystem state information like voltage and temperature values.
Telescience and telemetry data is transmitted by a spacecraft’s command and control system in response to commands uplinked from ground controllers, with each command executed at specific clock counts on board the spacecraft and stored temporarily in memory until transmission can take place.