A satellite or spacecraft could not function without a space bus. Space buses are the main structural components in this case. They carry payload and scientific instruments while ensuring an entire spacecraft functions properly. This is possible due to the many subsystems that make up a space bus, each with its distinct role. The functions and structural components of a space bus always depend on a space mission.
Why is it called a satellite bus?
A space bus, aka spacecraft platform, is called so because it works like a ground vehicle carrying passengers. Spacecraft platforms maintain all service systems of serial satellites. These satellites are connected to a platform, no matter if they are positioned in orbit. Besides, a spacecraft platform is the main body of a satellite or spacecraft, holding all the necessary components and scientific equipment necessary to accomplish the purpose of the space bus. Also, it looks exactly like a box or a bus, as you can see in satellite and spacecraft diagrams. The purpose of space bus doesn’t matter when it comes to design because in general they all look the same. They have a rectangle or cubic shape and house relevant systems for transferring data to remote terminals.
Experience the latest in space technology as you delve into the intricate world of space buses, the essential structural components that play a pivotal role in ensuring the proper functioning of satellites and spacecraft, carrying payloads and scientific instruments tailored to the unique demands of each space mission.
What does the spacecraft bus do?
There are many space bus functions, but a primary one is hosting satellite or spacecraft equipment such as cameras, electronics, and other components. Additional functions include:
- Acquiring data from the commanding center and sensors
- Distributing timely information
- Transferring data packets between control computers and onboard instruments
If a spacecraft platform wouldn’t ensure all these functions, a satellite would be useless, or its mission would be compromised. Spacecraft subsystems work in the background, but without these platforms, satellites, and spacecraft would not accomplish their missions in the harsh conditions of space. They would send erratic and faulty data that we couldn’t use for our exploration and research purposes.
Satellite bus details on major subsystems
Spacecraft bus technology is a home for six major subsystems. Each of these subsystems plays an important role in ensuring a given spacecraft can function properly. But let’s see which are these subsystems and what roles they play.
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- Electrical Power Subsystem (EPS). This subsystem converts the sunlight gathered by a satellite or spacecraft’s solar array panels into energy. This energy is necessary for the Science Instrument Payload, as well as other subsystems of the space vehicle, to operate.
- Command & Data Handling (C&DH) Subsystem. This system has a data storage/memory device, a Command Telemetry Processor (CTP), and Solid-State Recorder (SSR). Its purpose is to control how Science Instruments, Communication Systems, and SSR interact.
Attitude Control Subsystem (ACS), senses Observatory’s orientation and keeps it in a stable orbit. Without this subsystem, the Observatory course pointing to the spatial area that should be observed by Science Instruments would not work.
- Propulsion Subsystem (PS) ignites rockets and fuel tanks for maintaining the orbit after receiving commands from Attitude Control Subsystem (ACS).
- Communication Subsystem (CS). This subsystem acts like the Observatory’s mouth and ears, receiving commands from Operations Control Center (OCC) and sending the data back.
- Rocket Thrusters & Propellant Subsystem (RTPS). This subsystem is used for orbit station-keeping and orbit correction.
What are space buses used for?
As mentioned, the purpose of a spacecraft bus is to hold scientific instruments along with satellite or spacecraft payload. A satellite bus would not be useful if it couldn’t accommodate payloads or meet its mission’s requirements. Accommodation of payloads includes view fields, mechanical and thermal interfaces, duty cycles, data, volume, electromagnetic interference limits, contamination environments, spacecraft pointing control, etc. When it comes to mission requirements, these include communication and data memory links, onboard processing of data, orbit insertion and maintenance, radiation dose, redundancy degree, formation flying, etc.
All space missions depend on how the bus works and operates the satellite or spacecraft. For this reason, space companies are struggling to build the most advanced, durable buses that don’t break when space weather conditions are harsh. Most space buses are built in their basic version, while their customers can opt to enhance their performance depending on the mission for which they will be used.
All satellites and spacecraft have a space bus. Without it, they couldn’t work. While there are many types of space buses, they all have the same subsystems. However, we couldn’t use a space bus for a satellite that monitors the environment on a satellite that takes deep space images. Space companies struggle to build the most advanced space buses for us to have better exploration and research capabilities as a species.
