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I'm curious about how spacecraft would benefit having much more power for the same total mass. Solar panels are getting lighter, but would the extra power they could generate bring benefits to space missions?

I guess interplanetary missions using electric propulsion would benefit in having more power available for the thrusters, leading to shorter mission times. What about commercial or scientific satellites? Are their capabilities limited by power, or by other constraints such as volume and mass?

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    $\begingroup$ More power = more need for heat rejection $\endgroup$
    – Organic Marble
    Commented Oct 27, 2022 at 12:30
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    $\begingroup$ Everything is limited by one or more of size, weight and power (SWAP tradeoffs in engineering). $\endgroup$
    – Jon Custer
    Commented Oct 27, 2022 at 13:04

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In essence, satellites and other spacecraft are just computers in orbit, with their processing power limited by the amount of available electrical power. Either increasing the processing electrical efficiency or simply increasing the electrical power will therefore free up more processing power available within the spacecraft. This can have major consequences in spacecraft and mission design.

Some examples of the impact can be illustrated with the case of an Earth observation satellite. In many cases, the main instrument may require more power than is able to be generated. This is especially the case in active instruments such as radar systems. Because of this the instrument has to be operated in bursts. With more overall power available, the instrument can be operated for longer bursts or just more bursts overall.

With more processing power available, more processing of sensor or instrument payload data can be performed on board. Combining optical bands in images and performing compression may reduce the amount of data that has to be downlinked. This also makes it possible to operate the instrument longer or more often. It also may reduce response times when wanting to act on the data.

Staying with the downlink, having more electrical power available can increase the availability of the link and increase the link's bandwidth. This again can increase the usability of the instrument or increase the availability of the entire spacecraft. In the case of telecommunication satellites, this will also increase their availability and throughput.

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    $\begingroup$ Keeping in mind that with greater power comes greater waste heat, and cooling things in space is a nontrivial task, so even as solar panels become lighter and more efficient, you will find yourself mass and volume constrained by needing ever larger radiators as your power consumption goes up. $\endgroup$
    – Tristan
    Commented Oct 27, 2022 at 15:27
  • $\begingroup$ Thank you for your detailed answer! All these things you mention were exactly what I wanted to know about what could be done with additional power. I didn't know that space radars (and I guess all active RF imaging systems?) only operated in bursts due to power limitations. $\endgroup$
    – James Craft
    Commented Oct 28, 2022 at 0:10
  • $\begingroup$ By the way, @stefanlinden, do you have any sources where I could read further about this, or where this operation by bursts is mentioned? Thanks! $\endgroup$
    – James Craft
    Commented Oct 28, 2022 at 3:17
  • $\begingroup$ @JamesCraft I haven't been able to find one nice unified source of general information on this subject (yet), however for most historic and current satellite instruments you can find their so-called duty cycle. E.g. for ESA's Sentinel-1, most instrument modes are only active for 25 minutes within each ~99 minute orbit. $\endgroup$
    – stefanlinden
    Commented Oct 28, 2022 at 9:42
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    $\begingroup$ These are definitely very good resources to start on this subject, @JamesCraft. Especially SMAD ties all the different subsystems and their interlinks together, showing why many of these tradeoffs are necessary. $\endgroup$
    – stefanlinden
    Commented Oct 31, 2022 at 7:33

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