[dexen]

A doomsday weapon in space.

As the article mentions, the station will beam the collected energy down to Earth. Whether in visible light, microwave or any other spectral band, it will need two things for everyday operations:

- ability to point the beam at an arbitrary point on Earth, to track the collector ground installation, and

- ability to focus the beam to proper size

The second capability is crucial; if it's fixed focus - and one with sufficiently large footprint at that - and fixed orbit, it would be safe.

However having either adjustable focus, or adjustable orbit[1] makes this a proper weapon, due to the possibility of pointing multi-megawatt beam of energy at any point on the ground, with little to no countermeasures available. Whether "rogue hackers", or actual owners of the station, somebody would have the capability to destroy, without warning, large swaths of infrastructure on the ground.

I sure hope I'm very wrong about this - that somebody have figured out a way of inherently neutralizing the danger. But for now I treat the project as a doomsday weapon in space.

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[1] the later is a given to an extent, due to the need for orbital stationkeeping, and only possible to limit via provision of weak engines and/or limited fuel loadout

[adrianN]

It's a pretty shitty weapon because many countries have the capability to launch a bomb to the satellites and the satellites are way more expensive than the bomb.

[gotocake]

Depending on how close it is, you could destroy or at least damage the sattelite without even needing to launch anything. As a weapon, it would be downright silly to threaten a major world power with it. Of course if your goal is just to terrorize countries and groups without a space program, and assuming (big assumption granted) that other countries don’t interfere, then it would be a fairly exotic way of terrifying people. VERY expensive though, and diverting it from power generation to “kill” mode would be even more expensive.

All told, a country that could use this as a weapon doesn’t need to use this as a weapon.

[dexen]

It takes a good while to detect preparations for an attack with this kind of weapon & take the decision ("Mr President, the station has slightly shifted around, should we nuke it now?"), and it takes long time for any physical weapon to reach it.

A decent weapon would be space-burst version of ICBM. For intercontinental ground attack, the flight time is typically 20 minutes, but the most reasonable spot for the station is a geostationary orbit - some 36'000 km above equator. With a sensible speed on the order of 8km/s, it would take our missile around 1h25m to reach geostationary orbit assuming a naive straight-up trajectory; with any realistic trajectory it would take way longer. The space weapon would be able to rain terrible destruction in the meantime with impunity.

An alternative would be using ground- or space-based lasers, which give near instantaneous hit, but you'd need to precisely hit a proper part to guarantee fast disabling of the weapon. Merely hitting a random spot on the dish would probably not destroy it outright. You still have to account for the time to make the observations & take the decision. And the current breed of [high power] lasers is single-use only due to the destructive nature of generation of the large energy needed.

[adrianN]

That's all true, but a 2h window for destruction of single targets is not very useful against a modern military. There are enough ICBM silos that you can't destroy all of them before someone kills you DEATH STAR and then you still have to win the war that follows.

[AstralStorm]

Indeed, it is not a useful weapon in an all out war. I'd expect it to be used as surgical strike capability instead. Special operations. You can blame its use on inclement weather due to amount of electric charge this will paint on anything in path and resulting lightning storm.

[rurounijones]

And this is how we end up with https://en.m.wikipedia.org/wiki/Kessler_syndrome

[DennisP]

Based on a book I read on the subject, there's a way to make a phase-array microwave transmitter, which achieves the required focus by tuning into a reference signal from the receiving station on Earth. Using this system, if you try to transmit to an arbitrary spot you'll have a much more diffuse beam, and even the tight beam is only concentrated enough to raise the temperature several degrees. The receiving station is about the size of a ground-based solar array, but cheaper because it's just microwave antenna.

Another approach is to use a laser, at a frequency that gets absorbed by the atmosphere. Beam it to a high-altitude receiver station, which beams microwaves to a receiver directly below. But that way is a lot more expensive.

https://www.amazon.com/Case-Space-Solar-Power-ebook/dp/B00HN...

[JoeAltmaier]

It'll be the largest most fragile thing in the sky - kilometers wide and trivially destabilized/neutralized. Think black paint.

We seem to be arguing It'll be terribly expensive and difficult to make work, on one hand, and It'll be trivially easy to make into a weapon, on the other.

[AstralStorm]

Relatively easy to make work and quite uneconomical compared to ground solar fields. (Multiple.)

[JoeAltmaier]

But indefinitely expandable - up to millions of square kilometers. Try that next to a big city!

[JetSpiegel]

> pointing multi-megawatt beam of energy at any point on the ground, with little to no countermeasures available.

Can't you use a mirror to reflect a significant part of that energy back, wrecking the transmitter? If it is several mirrors focusing on the same point on earth (like a solar thermal power station), just jiggle the mirror on land to sweep the mirrors with a beam of energy.

[audunw]

> with little to no countermeasures available.

In the short term, maybe. But it wouldn't take much time to put in place comprehensive defense for such a system.

In a world with ICBMs, a weapon like this is not really something I'd be worried about. It'd be a pretty stupid weapon to use for an initial attack

The only thing I'm worried about is accidents or hacks.. if that's made impossible it should be fine

[dexen]

>In a world with ICBMs

Quite the opposite. ICBMs have somewhat symmetrical threat and defense model. You use similar technologies for both, and you have actionable amount of time - some 20 minutes - for observation, decision taking, and deployment of countermeasures.

Assuming the station is deployed on geostationary orbit (some 36'000 km above equator), the flight time of the electromagnetic waves is just over 0.1 second. Good luck deploying any countermeasures.