Comment by FranklinJabar
17 hours ago
> There is probably plenty of scope to optimize space radiators. It was never a priority until now and is "just" an engineering problem.
Well, it's a physics problem. The engineering solution is possibly not cost efficient. I'd put a lot of money that it isn't.
That bit reminded me of someone who wanted us to design a patch the size of a small postage stamp, at most 0.2mm thick, so you could stick on products. It was to deliver power for two years of operation, run an LTE modem, a GNSS receiver, an MCU, temperature and humidity sensor and would cost $0.10. And it would send back telemetry twice per day.
'A mere matter of engineering'.
The conversation went something like this (from memory):
- We can't do that
- Why not?
- Well, physics for one.
- What do you mean?
- Well, at the very least we need to be able to emit enough RF-energy for a mobile base station to be able to detect it and allow itself to be convinced it is seeing valid signaling.
- Yes?
- The battery technology that fits within your constraints doesn't exist. Nevermind the electronics or antenna.
- Can't you do something creative? We heard you were clever.
I distinctly remember that last line. But I can't remember what my response was. It was probably something along the lines of "if I were that clever I'd be at home polishing my Nobel medal in physics".
Even the sales guy who dragged me into this meeting couldn't keep it together. He spent the whole one hour drive back to the office muttering "can't you do something creative" and then laughing hysterically.
I think the solution they went for was irreversible freeze and moisture indication stickers. Which was what I suggested they go for in the first 5 minutes of the meeting since that a) solved their problem, and b) is on the market, and c) can be had for the price point in bulk.
6 replies →
All you need to do is make use of a higher dimension to pack stuff into. And then mass produce to bring costs down. How hard can that be?
1 reply →
Not only is it not cost-effective, it's pointless (in this context).
Radiators works almost just as well on Earth. Convection and conduction more than make up the difference.
What makes you so sure? SpaceX already has thousands of 6 kW networking racks flying around in LEO and they dissipate their heat just fine, and are plenty cost-effective. You think they can't do any better than that with a new design specifically optimized for computing rather than networking?
Probably, but they likely can't do better than we can do on Earth. Networking in space offers specific advantages that are not easy to replicate on Earth. Data centers in space don't have clear advantages beyond easily debunked ideas about cooling and power.
I'm not talking about the whole idea, just the heat dissipation part. So many people in this thread seem so sure this is impossible because you can't radiate heat in space, completely ignorant to the fact that SpaceX is already dissipating over 20 MW of solar power in LEO in a reasonably cost-effective manner.
The advantage of 24/7 solar power is clear, obvious, and undeniable, it's just a question of whether that's outweighed by the other disadvantages.
The solar panels on the newest satellites can deliver 6kW but the power that satellite actually uses is less. The satellite is only using 300W[1] during the dark phase of it's orbit when it can use it's entire mass to cool down. Is that limit because of the battery or is it because the satellite needs to radiate all the heat it acquired from the other half of the time in the sun?
[1] https://lilibots.blogspot.com/2020/04/starlink-satellite-dim...
Looks like that's a purely speculative assumption the blog author made, not a fact. I'm not sure why he made that assumption given that Starlink doesn't actually stop working at night.
Fair point that in SSO you'd need 2-3x the radiator area (and half the solar panels, and minimal/no batteries). I don't think that invalidates my point though.
1 reply →