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What is a Satellite Bus?
A satellite bus, also referred to as a spacecraft bus or satellite platform, is the standardized, modular structure or framework that forms the core of a satellite. It carries and supports the primary systems and subsystems required for the satellite’s operation, while the payload, which varies depending on the satellite’s purpose and mission, is attached to the bus.
The main components of a satellite bus typically include:
Structural Subsystem
This provides the mechanical support for the entire satellite, including the payload and other subsystems. It is designed to withstand the stresses of launch and the harsh conditions of space.
Power Subsystem
This generates, stores, and distributes electrical power to the satellite’s various systems. Solar panels are often used to collect sunlight and convert it into electricity, while batteries store the power for use during periods when the satellite is in Earth’s shadow or during peak power demand.
Attitude Control and Determination Subsystem
This system maintains the satellite’s orientation and position in space, ensuring that antennas, sensors, and solar panels are correctly pointed. It usually consists of sensors to measure the satellite’s attitude and position, and actuators, such as thrusters or reaction wheels, to make adjustments as needed.
Thermal Control Subsystem
This regulates the temperature of the satellite to protect sensitive electronics and other components from extreme temperature fluctuations. It typically employs passive techniques, such as insulation, and active techniques, such as heaters and radiators, to maintain a stable temperature environment.
Propulsion Subsystem
This provides the capability to change the satellite’s orbit or maintain its position. Depending on the mission requirements, propulsion can include chemical, electric, or other propulsion technologies.
Communication Subsystem
This enables communication between the satellite and ground stations, facilitating the transmission of commands, telemetry, and payload data. The communication subsystem typically consists of antennas, transmitters, and receivers.
Pros and Cons of Using a Standardized Satellite Bus
Using standardized satellite buses offers several advantages and disadvantages, which are outlined below:
Pros
Cost Savings
Standardized satellite buses can significantly reduce the overall cost of satellite development and production by leveraging economies of scale, using off-the-shelf components, and reusing proven designs across multiple missions.
Faster Development
Since standardized satellite buses use pre-designed and tested components and subsystems, the satellite development process can be accelerated. This reduces the time from concept to launch and allows satellite operators to respond more quickly to market demands or technological advancements.
Modular Design
The modular nature of standardized satellite buses allows for easier integration of various payloads, catering to a wide range of applications, such as communication, Earth observation, navigation, and scientific research.
Reliability
Standardized satellite buses often have a track record of reliability due to their use in multiple missions, which can lower the risk of failures and increase confidence in the satellite’s performance.
Simplified Integration and Testing
Using a standardized satellite bus simplifies integration and testing processes, as the bus has established interfaces and compatibility with a variety of payloads and subsystems.
Cons
Limited Customization
Standardized satellite buses may not offer the same level of customization and flexibility as a bespoke satellite design, which could be a drawback for missions with unique requirements or constraints.
Potential for Obsolescence
As technology advances rapidly, standardized satellite buses may become outdated more quickly compared to custom-built satellites specifically designed with the latest technology. This can limit the satellite’s capabilities or lifespan.
Compatibility Challenges
In some cases, integrating a payload with a standardized satellite bus may require additional engineering efforts to ensure compatibility, which could offset some of the cost and time savings.
One-Size-Fits-All Approach
Standardized satellite buses may not always be the optimal solution for specific mission requirements, as they may not cater to unique needs such as specific orbit types, payload accommodations, or power requirements.
Market Limitations
The availability of standardized satellite buses can be limited to certain manufacturers, which might not cover the full range of satellite sizes and applications required by all customers.
Bottom Line
Using standardized satellite buses can provide significant cost and time savings, along with reliability and modularity. However, they may not always be the optimal solution for missions with unique requirements or rapidly advancing technology. Satellite operators must weigh the pros and cons based on their specific mission needs and objectives before choosing a standardized satellite bus.
Standardized Satellite Bus Products
Several companies offer standardized satellite bus products, here are some notable manufacturers:
- Northrop Grumman: They offer satellite buses such as the GEOStar and ESPAStar platforms for various applications.
- Lockheed Martin: They produce the LM satellite bus platform.
- Ball Aerospace: They offer the BCP (Ball Configurable Platform) series, such as BCP-100, BCP-500, and BCP-2000, for a range of satellite applications.
- Boeing: They produce the 702 satellite bus platform.
- Surrey Satellite Technology Limited (SSTL): They offer a range of small satellite buses, including the SSTL-Cube, SSTL-Micro, and SSTL-Mini.
- Sierra Nevada Corporation: They provide the SN-200, SN-100, and SN-1000 satellite bus platforms.
The above list is not exhaustive.
These companies cater to a diverse range of satellite applications and mission requirements, providing various sizes, capabilities, and customization options in their satellite bus offerings. Note that some companies also offer standardized payloads that can be integrated in with their standardized satellite bus.
Examples of Satellites That Use a Standardized Satellite Bus
Here are some examples of customer satellites that use a standardized satellite bus from various manufacturers:
| Manufacturer | Satellite Bus | Example Customer Satellite |
|---|---|---|
| Northrop Grumman | LEOStar-2 | TESS (Transiting Exoplanet Survey Satellite) |
| Airbus Defence and Space | Eurostar E3000 | Inmarsat-6 F1 and F2 |
| Airbus Defence and Space | OneSat | EUTELSAT QUANTUM |
| Lockheed Martin | A2100 | Advanced Extremely High Frequency (AEHF) satellites |
| Thales Alenia Space | Spacebus NEO | EUTELSAT KONNECT |
| Maxar Technologies (formerly SSL) | SSL 1300 | SES-12 |
| Ball Aerospace | BCP-5000 | WorldView-3 |
| Boeing | 702MP | Intelsat 29e |
| Surrey Satellite Technology Limited (SSTL) | SSTL-X50 | KazEOSat-2 (KazSTSAT) |
| Sierra Nevada Corporation | SN-100 | ORBCOMM Generation 2 (OG2) satellites |
| RUAG Space | SmallGEO | Hispasat 36W-1 |
Cost of Standardized Satellite Buses
The cost of a standardized satellite bus can vary widely depending on various factors such as the size, complexity, capabilities, and the manufacturer. Satellite buses can range from small, CubeSat-sized platforms to large geostationary satellite buses, which significantly impacts the price.
For small satellite buses, such as CubeSats or nanosatellites, the cost can range from tens of thousands to a few hundred thousand US dollars. For example, a basic 3U CubeSat bus might cost around $30,000 to $50,000, whereas more complex small satellite buses could cost several hundred thousand dollars.
For medium-sized satellite buses, often used for Earth observation or scientific missions, the cost can range from a few million to tens of millions of dollars.
For larger satellite buses, typically used for geostationary communication satellites, the cost can range from tens of millions to over a hundred million dollars.
It is important to note that these costs only cover the satellite bus itself and do not include the payload, launch costs, ground segment, or the operation and maintenance of the satellite. The total cost of a satellite mission would be significantly higher when considering all these factors.
Keep in mind that the prices provided here are rough estimates and may not accurately reflect the current market, as costs can change due to technological advancements, market conditions, or the specific requirements of a satellite mission.