Satellite EPS (Electrical Power Systems) on the market

In this post, we provide an overview of satellite EPS or Electrical Power Systems and share details of various products on the global market – if you’re familiar with this technology and would like to skip over the introductory material to get straight to the product listings, please click here.

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The primary role of the satellite EPS is to supply other systems in the satellite with the necessary electrical power to operate effectively.

The source of the power is the energy collected from the solar panels which are exposed to direct solar radiation or to indirect radiation from albedo.

Batteries are installed alongside the solar panels to store energy which can then be used when the satellite regularly passes through the shadow of the Earth. Batteries can also help to provide sufficient power during periods of peak demand by the payload on-board the satellite.

The collected and stored power must then be distributed to other systems throughout the satellite as needed by the EPS.

The satellite itself may need multiple voltage levels for different sensors and sub-systems. Managing these levels is another function of the system; the satellite EPS houses a power conditioning unit which is able to deliver the required amount of electrical power at several voltages. It also plays an important role in monitoring spacecraft status.

Subsystems such as power conversion boards and interface, Power Conditioning and Distribution Unit (PCDUs), and Maximum Power Point Trackers (MPPTs) all play a role in the power management and control process.

Alongside power provision and management, the EPS plays a crucial role in monitoring the satellite’s health, as discussed in the next section.

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Assessing satellite status

The health of the satellite needs to be checked regularly to make sure that there are no major problems in any sub-system during its operations in orbit.

Collecting routine information from various sub-systems and sensors is also a core function of the EPS. This involves measuring various important voltages, currents, and temperatures which are called the “Housekeeping Parameters.”

These are communicated back to the ground as a part of the telemetry of the satellite for operators to keep track of the overall health of their system and guard against potential faults or poor performance.

The high levels of radiation in space can cause ”single event latch-up” in the semiconductor devices on the satellite.

This can damage some of the components on the satellite if the power is not turned off quickly enough, so the EPS is also required to protect the satellite and its sub-systems against over-currents.

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Selecting an Electrical Power System for a space mission

When assessing whether a particular EPS is the best fit for your mission, the typical space hardware criteria of Size, Weight, and Power (SWaP) are particularly important.

• Size – power equipment can take up lots of spacecraft volume, relative to the overall size, and the power that can be generated by solar panels is a function of their surface area, meaning size is a very important characteristic.
• Weight – similarly, EPS hardware can account for a significant amount of the mass budget. Batteries in particular are relatively heavy compared to other subsystems. So weight is a key limiting factor.
• Power – obviously, selecting the most suitable EPS will require a clear indication of your satellite’s overall power budget range, and the operational power requirements of the EPS itself will also need to be factored in.

In addition to these usual criteria, some other important factors to weigh up are:

• EPS contents – note that different suppliers market different product formulations under the label “Electrical Power System” (e.g. solar panels, PCDUs, MPPTs, conversion cards etc.) so ensure that you know what setup is required for your mission.
• Heritage – a power system failure is fatal to a mission, so ensure that you de-risk this as much as possible by querying any system’s operational heritage.
• Interoperability – as an EPS can play such a key role in satellite health monitoring (as described in the previous section) the system’s interoperability and interface capacity with the spacecraft’s communications system and on-board computer is very important.

In addition, for the CubeSat form factor there are some additional design considerations and conventions that have emerged from the industry, take a look in the next section.

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Electrical CubeSat requirements

There are certain electrical requirements that are recommended for the standard CubeSat form factor which EPSs should adhere to:

• If the satellite features a rechargeable battery it should be fully discharged or deactivated for the launch.
• In order to avoid RF or electrical interference of primary payloads, or the launch vehicle itself, no CubeSat electronics should be active during launch.
• For each CubeSat at least one deployment switch is required, although two are recommended. These should be located at clearly designated points.
• If developers wish to perform testing and battery charging after integration they must provide ground support equipment (GSE) that connects to the CubeSat through designated data ports.
• A remove before flight (RBF) pin is usually required in order to deactivate the CubeSat during integration outside the P-POD or alternative launch separation system. This pin will then be removed once the CubeSats are placed inside the P-POD, and it must fit within the designated data port.

More information on these recommendations can be found in this paper on CubeSat Design Specifications [PDF].

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Satellite EPS products on the global market

In this section, you can explore Electrical Power Systems available on the global market. These listings will be updated when new satellite EPS products are added to the global marketplace for space at satsearch.co – so please check back for more or sign up for our mailing list to get all the updates.

We have also put together an overview of CubeSat solar panels and solar cells if you need additional power components to complete your satellite and an overview of on-board computers should you require ancillary control systems.

You can click on any of the links or images below to find out more about each of the products. You can also submit a request for information (RFI) on the product pages or send us a general query using our RFI tool to discuss your specific needs, and we will use our global networks of suppliers to find a system to meet your specifications.

Please note that this overview primarily includes integrated EPS products which may contain the following:

• Solar panels to generate power,
• Power regulation and power conversion systems for solar generation, such as Maximum Power Point Trackers (MPPTs),
• Batteries to store energy until needed, and
• Power Conditioning and Distribution Units (PCDUs) to manage energy output from the EPS to the satellite.

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Related technologies and further reading

At the links below you can find a range of satsearch articles that will be useful for learning more about this topic, or that feature other categories of technologies which you may need to consider in your mission.

• Satellite batteries on the market
• CubeSat thrusters and in-space propulsion
• Software-defined radios (SDRs) for space
• On-board computers (OBCs) for space
• Optical payloads for space
• Satellite software providers on the global market
• Payload processors for satellites
• A brief introduction to the space supply chain

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