[FranklinJabar]

> 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.

[bborud]

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.

[jacquesm]

'A mere matter of engineering'.

[bborud]

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.

[jacquesm]

That's so hilarious. I've had a couple that went in that direction but nothing to come close.

To be fair though, there is a lot of tech that to me seems like complete magic and yet it exists. SDR for instance, still has me baffled. Who ever thought you'd simply digitize the antenna signal and call it a day, hardware wise, the rest is just math, after all.

When you get used to enough miracles like that without actually understanding any of it and suddenly the impossible might just sound reasonable.

> Can't you do something creative? We heard you were clever.

Should be chiseled in marble.

[bborud]

The purely digital neighborhood of the SDRs is much easier to explain than the analog rat droppings between the DAC/ADC and the antenna. That part belongs to dark wizards with costly instruments that draw unsettling polar plots, and whose only consistent output is a request for even pricier gear from companies whose names sound an awful lot like European folk duos.

The digital end of SDRs are simple. Sample it, then once you have trapped the signal in digital form beat the signal into submission with the stick labeled "linear algebra".

(Nevermind that the math may be demanding. Math books are nowhere near as scary as the Sacred Texts Of The Dark Wizards)

"Rohde & Schwarz — live at the VNA, 96 dB dynamic range, one night only."

[jacquesm]

> whose names sound an awful lot like European folk duos.

That had me laughing out loud, you should have left the name out to make it more of a puzzler :)

I apparently have been drawn to the occult for a long time and feel more comfortable with coils, capacitors and transmission lines than I do with the math behind them. Of course it's great to be able to just say 'ridiculously steep bandpass filter here' and expect it to work but I know that building that same thing out of discrete components - even if the same math describes it - would run into various very real limitations soon.

And here I am on a budget SDR speccing a 10 Hz bandfilter and it just works. I know there must be some downside to this but for the life of me I can't find it.

[klaff]

I like your sales guy. Might have punched them after a while but that's right up there with the time someone tried to tell me there was no iron in steel because it wasn't in the ingredients list. And this someone sold stamped steel parts!

[verzali]

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?

[bborud]

Skippy the Magnificent will solve this for us.

(reference to a character in the Expiditionary Force series by Craig Alanson

Only a very small portion of his physical presence is in local spacetime, with the rest in higher spacetime. He can expand his physical presence from the size of an oil drum or shrink to the size of a lipstick tube. He can’t maintain that for long without risking catastrophic effects. If he did, he would lose containment, fully materialize in local spacetime and occupy local space equal to one quarter the size of Paradise. The resulting explosion would eventually be seen in the Andromeda Galaxy.)

[drtz]

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.

[Ajedi32]

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?

[verzali]

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.

[Ajedi32]

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.

[undersuit]

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...

[Ajedi32]

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.

[undersuit]

Article doesn't say the satellites stop working in their dark phase, it says they consume 300W in the dark phase based on some battery math.

[Ajedi32]

If the satellite requires ~3,000 W to work in the light phase (based on solar panel size), then reducing that to 300 W during the dark phase would most definitely require it to "stop working".

The battery math is based on purely speculative assumptions the author made about cycle lifetimes. It's not grounded in any real, concrete information like the solar panel power calculations are.