[moeadham]

In fairness, solar cells can be about 5x more efficient in space (irradiance, uptime).

[ben_w]

The quoted "1 TW of photovoltaic cells per year, globally" is the peak output, not the average output. They're only about 20% higher peak output in space… well, if you can keep them cool at least.

[pantalaimon]

But there are no clouds in space and with the right orbit they are always facing the sun

[cowsandmilk]

It is more than 5x less expensive to get surface area on earth’s surface.

[schiffern]

The dominant factor is "balance of system" aka soft costs, which are well over 50%.[0]

Orbit gets you the advantage of 1/5th the PV and no large daily smoothing battery, but also no on-site installation cost, no grid interconnect fees, no custom engineering drawings, no environmental permitting fees, no grid of concrete footers, no heavy steel frames to resist wind and snow loads. The "on-site installation" is just the panels unfolding, and during launch they're compact so the support structure can be relatively lightweight.

When you cost building the datacenter alone, it's cheaper on earth. When you cost building the solar + batteries + datacenter, it (can be) cheaper in space, if you build it right and have cheap orbital launch.

[0] https://en.wikipedia.org/wiki/Balance_of_system

[bob1029]

Right now it is.

However, the amount of available land is fixed and the demand for its use is growing. Solar isn't the only buyer in this real estate market.

[philistine]

Does that include all the required radiators to vent heat?

[chartisma]

and of course, the continuous opposite boost needed to prevent the heat vent from knocking them out of orbit.

[sltkr]

Fortunately there are no downsides to launching solar cells into space that would offset those gains.

[__alexs]

Solar cells have exactly the same power rating on earth as in space surely? What would change is their capacity factor and so energy generation.

[crabmusket]

Solar modules you can buy for your house usually have quoted power ratings at "max STC" or Standard Testing Conditions, which are based on insolation on Earth's surface.

https://wiki.pvmet.org/index.php?title=Standard_Test_Conditi...

So, a "400W panel" is rated to produce 400W at standard testing conditions.

I'm not sure how relevant that is to the numbers being thrown around in this thread, but thought I'd provide context.

[kortex]

Satellites can adjust attitude so that the panels are always normal to the incident rays for maximum energy capture. And no weather/dust.

You also don't usually use the same exact kind of panels as terrestrial solar farms. Since you are going to space, you spend the extra money to get the highest possible efficiency in terms of W/kg. Terrestrial usually optimizes for W/$ nameplate capacity LCOE, which also includes installation and other costs.

[bastawhiz]

The atmosphere is in the way, and they get pretty dirty on earth. Also it doesn't rain or get cloudy in space

[Waterluvian]

Atmospheric derating brings insolation from about 1.367KW/m2 to about 1.0.

And then there’s that pesky night time and those annoying seasons.

It’s still not even remotely reasonable, but it’s definitely much higher in space.

[tenuousemphasis]

Now do waste heat.

[DoctorOetker]

Here you go:

https://news.ycombinator.com/item?id=46862869

[bastawhiz]

And how much of that power would be spent on high speed communications with Earth that aren't, you know, a megabit or two per second

[chaos_emergent]

I grew up on a rural farm in California with a dial-up connection that significantly hampered my ability to participate in the internet as a teenager. I got Starlink installed at my parents' house about five years ago, and it's resulted in me being able to spend considerably more time at home.

Even with their cheapest home plan, we're getting like 100 Mbps down and maybe 20 to 50 up. So it's just not true at all that you would have connections that are a megabit or two per second.

[tootie]

The intractable problem is heat dissipation. There is to little matter in space to absorb excess heat. You'd need thermal fins bigger than the solar cells. The satellite's mass would be dominated by the solar panels and heat fins such that maybe 1% of the mass would be usable compute. It would be 1000x easier to leave them on the moon and dissipate into the ground and 100000x easier to just keep making them on earth.

[crote]

That's pretty much a solved problem. We've had geostationary constellations for TV broadcast at hundreds of megabytes for decades now, and lasers for sat-to-sat comms seems to be making decent progress as well.

[chartisma]

and, of course and inter-satellite comms and earth base station links to get the data up and down. Starlink is one thing at just above LEO a few hundred km and 20km apart, but spreading these around 10s of thousands of km and thosands of km apart is another thing