zlacker

What about sourcing and the cost of energy? Solar Panels more efficient, no bad weather, and 100% in sunlight (depending on orbit) in space. Not that it makes up for the items you listed, but it may not be true that everything is more difficult in space.

>>WillPo+(OP)
I'm stretched to think of one thing that is easier in space. Anything I could imagine still requires getting there (in one piece)

>>WillPo+(OP)
Solar panels in space are more efficient, but on the ground we have dead dinosaurs we can burn. The efficiency gain is also more than offset by the fact that you can't replace a worn out panel. A few years into the life of your satellite its power production drops.

>>WillPo+(OP)
Let's say with no atmosphere and no night cycle, a space solar panel is 5x better. Deploying 5x as many solar panels on the ground is still going to come in way under the budget of the space equivalent.

>>edoceo+W1
Achieving a zero-gravity environment, or a vacuum?

>>edoceo+W1
Death, and some science. That's it?

>>pclmul+f2
> Solar panels in space are more efficient...

... if you completely ignore the difficulty of getting them up there. I'd be interested to see a comparison between the amount of energy required to get a solar panel into space, and the amount of energy it produces during its lifetime there. I wouldn't be surprised if it were a net negative; getting mass into orbit requires a tremendous amount of energy, and putting it there with a rocket is not an efficient process.

>>duskwu+gc
My sketchy napkin math gives an order of magnitude of a few months of panel output to get it in space.

5kg, 500W panel (don’t exactly know what the ratio is for a panel plus protection and frame for space, might be a few times better than this)

Say it produces about 350kWh per month before losses.

Mass to LEO is something like 10x the weight in fuel alone, so that’s going to be maybe 500kWh. Plus cryogenics etc.

So not actually that bad

>>WillPo+(OP)
just take cost of getting kg in space and compare it to how much solar panel will generate

Current satellites get around 150W/kg from solar panels. Cost of launching 1kg to space is ~$2000. So we're at $13.3(3)/Watt. We need to double it because same amount need to be dissipated so let's round it to $27

One NVidia GB200 rack is ~120kW. To just power it, you need to send $3 240 000 worth of payload into space. Then you need to send additional $3 106 000 (rack of them is 1553kg) worth of servers. Plus some extra for piping

>>3eb798+c3
That's with current launch costs, right? Nobody is claiming it's economic without another huge fall in launch costs, but that's what SpaceX is doing.

>>esquiv+xb
Horseshoes.

>>pclmul+f2
If they plan to put this things in a low orbit their useful life before reentry is low anyway.

A quick search gave me a lifespan of around 5 years for a starlink satellite.

If you put in orbit a steady stream of new satellites every year maintenance is not an issue, you just stop using worn out or broken ones.

>>3eb798+c3
And it's not the same at all. 5x the solar panels on the ground means 5x the power output in the day, still 0 at night. So you'd need batteries. If you add in bad weather and winter, you may need battery capacity for days, weeks or even months, shifting the cost to batteries while still relying on nuclear of fossil backups in case your battery dies or some 3/4/5-sigma weather event outside what you designed for occurs.

>>cmenge+Yz
Or you put the data centers at different points on earth?

Or you float them on the ocean circumnavigating the earth?

Or we put the datacenters on giant Zeppelins orbiting above the clouds?

If we are doing fantasy tech solutions to space problems, why not for a million other more sensible options?

>>Punchy+Xu
Over 10 years ago, the best satellites had 500W/kg [2]. Modern solar panels that are designed to be light are at 200g per sqm [1]. That's 5sqm per kg. One sqm generates ca. 500W. So we're at 2.5kW per kg. Some people claim 4.3kW/kg possible.

Starship launch costs have a $100/kg goal, so we'd be at $40 / kW, or $4800 for a 120kW cluster.

120kW is 1GWh annually, costs you around $130k in Europe per year to operate. ROI 14 days. Even if launch costs aren't that low in the beginning and there's a lot more stuff to send up, your ROI might be a year or so, which is still good.

[1] - https://www.polytechnique-insights.com/en/columns/space/ultr... [2] - https://space.stackexchange.com/questions/12824/lightest-pos...

>>Certha+gD
> Or you put the data centers at different points on earth? > Or you float them on the ocean circumnavigating the earth?

What that does have to do with anything? If you want to solar-power them, you still are subject to terrestrial effects. You can't just shut off a data center at night.

> Or we put the datacenters on giant Zeppelins orbiting above the clouds?

They'd have to fly at 50,000+ ft to be clear of clouds, I doubt you can lift heavy payloads this high using bouyancy given the low air density. High risk to people on the ground in case of failure because no re-entry.

> If we are doing fantasy tech solutions to space problems, why not for a million other more sensible options?

How is this a fantasy? With Starlink operational, this hardly seems a mere 'fantasy'.

>>cmenge+wD
What if you treat that launch costs goal as just a marketing promise. Invest in reality, not in billionaire's fantasies.

>>mike_h+Dx
It wouldn't make sense if launch was free and it will never be

>>cmenge+WI
> You can't just shut off a data center at night.

Why not?

A capacity problem can be solved by having another data center the other side of the earth.

If it's that the power cycling causes equipment to fail earlier, then that can be addressed far more easily than radiation hardening all equipment so that it can function in space.

>>serall+my
Terrestrial data centers save money and recoup costs by salvaging and recycling components, so what you're saying here is that space-based datacenters are even less competitive than we previously estimated.

>>edoceo+W1
Noise insulation.

>>mkespe+FK
> What if you treat that launch costs goal as just a marketing promise.

Then it's roughly 10x-15x and still works.

> Invest in reality, not in billionaire's fantasies.

SpaceX has dramatically reduced payload cost already. How is that a fantasy?

>>ndsipa+eQ
Because GPUs are expensive, much more expensive than launch costs if they get starship to the low end of the range they’re aiming for, and you want your expensive equipment running as much as possible to amortize the cost down?

>>pclmul+f2
No idea how quickly they wear out in space with 24x7 irradiance and space temps, but on the earth, they’re at something like 80% capacity after 25 years. So seems like you could control how long they have via overpanelling?