[tensor]

How much of that power is radiated as the radio waves it sends?

[hirsin]

Good point - the comms satellites are not even "keeping" some of the energy, while a DC would. I _am_ now curious about the connection between bandwidth and wattage, but I'm willing to bet that less than 1% of the total energy dissipation on one of these DC satellites would be in the form of satellite-to-earth broadcast (keeping in mind that s2s broadcast would presumably be something of a wash).

[adrian_b]

I am willing to bet that more than 10% of the electrical energy consumed by the satellite is converted into transmitted microwaves.

There must be many power consumers in the satellite, e.g. radio receivers, lasers, computers and motors, where the consumed energy eventually is converted into heat, but the radio transmitter of a communication satellite must take a big fraction of the average consumed power.

The radio transmitter itself has a great efficiency, much greater than 50%, possibly greater than 90%, so only a small fraction of the electrical power consumed by the transmitter is converted into heat and most is radiated in the microwave signal that goes to Earth's surface.

[mlyle]

I doubt half the power is to the transmitter, and radio efficiency is poor -- 20% might be a good starting point.

[synctext]

Is the SpaceX thin-foil cooling based on graphene real? Can experts check this out?

"SmartIR’s graphene-based radiator launches on SpaceX Falcon 9" [1]. This could be the magic behind this bet on heat radiation through exotic material. Lot of blog posts say impossible, expensive, stock pump, etc. Could this be the underlying technology breakthrough? Along with avoiding complex self-assembly in space through decentralization (1 million AI constellation, laser-grid comms).

[1] https://www.graphene-info.com/smartir-s-graphene-based-radia...

[PunchyHamster]

Entirely depends on band, at 10GHz more like 40%, at lower frequencies more, for example FM band can even go to 70%

[adgjlsfhk1]

the majority is likely in radio waves and the inter satellite laser communication

[hdgvhicv]

Inter sat comms cancels out - every kw sent by one sat is received by another.

[nosianu]

The radio receiver and transmitter are additional hardware and energy consumption. They add to the heat, not subtract from it.

[jeltz]

I think you missed the point. If you have a 100 MW communicstion satellite and a 100 MW compute satellite those are very different beasts. The first might send 50% of the energy away as radio communication making it effectively a 50 MW satellitefor cooling purposes.