Spacecraft design

The design of spacecraft covers a broad area, to include unmanned spacecraft design (satellites and planetary probes), and manned spacecraft design (spaceships and space stations). The design and engineering of spacecraft is somewhat related to that of rockets and missiles. An important difference though is that spacecraft operate part or all of their life in vacuum and interplanetary space environment.

Related Topics:
Spacecraft - Unmanned spacecraft - Satellite - Planetary probe - Spaceship - Space station - Rocket - Missile

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Spacecraft design brings together aspects of various techniques and technologies, namely:

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• Astronautics for mission design and derivation of the design requirements,
• Systems engineering for maintaining the design baseline and derivation of subsystem requirements, said subsystems listed below:
• Telemetry, Telecommand, and Communications (TTC) subsystem, which uses technologies and techniques of terrestrial radio and digital communications to communicate with the ground,
• On-Board Data Handling (OBDH) subsystem, which includes on-board computers and computer buses. Again this subsystem is based on terrestrial technologies,
• Software which runs all the on-board applications and also low-level software. This subsystem is very similar to terrestrial real-time and embedded software designs,
• Electrical subsystem, which generates, stores and distributes the electrical power to all the on-board equipments,
• Attitude and Orbit Control (AOCS) subsystem, which uses control theory to point the spacecraft correctly, and maintain or change the orbit according to the mission profile; Although the techniques in AOCS design are common with terrestrial methods, the hardware used for actuation and sensing in space is usually very specific to spacecraft,
• Thermal Control subsystem, which maintains environmental conditions compatible with operations of the spacecraft equipments; This subsystem has very space-specific technologies, since in space, radiation and conduction usually dominate as thermal effects, by opposition with Earth where convection is typically the main one,
• Propulsion subsystem, which provides means of transporting the spacecraft from one orbit to another. This is the only technology which is really specific to spacecraft design. Popular culture has made a cliche of spacecraft propulsion engineers, as embodied by the term rocket science,
• Mechanical and Structure subsystem, which addresses the structural components and mechanisms within the spacecraft configuration. These include for instance beams, panels, and deployable appendages or separation devices (to eject from the launcher rocket).

Spacecraft design was born as a discipline in the 50s and 60s with the advent of American and Russian space exploration programs. Since then it has progressed, although typically less than comparable terrestrial technologies. This is for a large part due to the challenging space environment, but also to the lack of basic R&D, and to other cultural factors within the design community.

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