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Routine_Shine_1921 t1_ixm18ja wrote

No. First of all, that's imaginary technology, a laser beam is highly focused light, which is the opposite of a shield, it's narrow, you can't really use it to cover a wide area.

Second, the energy requirements would be absolutely prohibitive.

Third, this particles are moving at orbital speeds, no matter how high powered your laser is, it won't be fast enough.

Finally, even if you could do it, it'd be far heavier than having shielding.

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fencethe900th t1_ixmp7g3 wrote

Lasers can be aimed.

The larger the cross section the more objects you'd need to deflect, but also the more space you have for something like a nuclear reactor. If it's in orbit of a planet and small then it could be in the protection of larger stations on the ground or in orbit.

Orbital speeds are practically stationary compared to the speed of light, and lasers can be aimed incredibly fast.

I'm not sure how a laser array would be heavier than shielding. A Whipple shield would be lighter but if you're getting serious about shielding it's probably because you have to shield against some serious objects.

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Routine_Shine_1921 t1_ixmr45e wrote

I mention this in another comment. I was answer OPs question, where he went for actual shielding, as in passive shielding. Which is basically impossible.

If you're instead going for detecting and tracking debris, and then aiming a laser at it, it's a different story. It's equally hard, and basically impossible with current technology once you take into account the size and mass of such a laser and its power requirements.

The point is that, if you can do this, then you don't need shielding. Same about the "serious objects" you talk about. If you have detected debris large enough to be detected, enough time in advance to point a laser at it, then you've detected it enough time in advance to maneuver and avoid it entirely. Shielding is precisely about smaller objects that you don't know about until they hit you.

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fencethe900th t1_ixn84jb wrote

Shifting a relatively small object with a laser is much easier than shifting an entire spaceship. Right now shielding is for small things, but not forever. Isaac Arthur has some really good videos dealing with this and other topics.

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Usernamenotta t1_ixm3hr0 wrote

Erm, lasers move at light speed, which, as far as we know, is the only constant speed. There is no such thing as 'orbital speed'. You could collide with a speck of stardust at 1km/h or at 36km/s, it all depends on how both of you are travelling

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Routine_Shine_1921 t1_ixm42nf wrote

You missed my point. Lasers aren't solid walls, a powerful enough laser could destroy a particle by heating it up. That energy transfer takes TIME. More often than not, that time is relatively long, which is why we don't have goddamn laser weapons.

A micrometeroid coming in at your ship would only cross that laser for an infinitesimal fraction of a second, and therefore no significant energy transfer would occur.

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Usernamenotta t1_ixma5k5 wrote

It kinda depends on how you design the stuff. I mean, light has kinetic energy as well. And here we are not talking about melting a tennis ball made of wolfram, but rather changing the energy of a speck of dust. A strong enough laser beam probably has enough kinetic energy to deviate that speck of dust and the laser beam impacting the speck would be the equivalent of a building taking a nuclear blastwave in the face.

Also, this is irrelevant for what I said. You missed my point. You could collide with that thing at 1m/h, meaning you could have the thing in the laser sights for quite some time, because you are travelling 'behind it', basically making it look stationary for your ship, or you could collide head on at 36km/s because your velocity vectors are opposed to each other.

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House13Games t1_ixmahh6 wrote

So at what range can you detect a dust particle? If you come creeping up behind it and gently nudge it, there's no need for lasers. And what if it IS a tennis ball sized bit of debris?

I posit that anything travelling at such high velocity as to endanger the ship, will not be detectable in time to get an energy weapon on it long enough to vaporize it and give it time to disperse.

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fencethe900th t1_ixmmz55 wrote

It all depends on how much power you have on hand for radar pulses. Provided you have the power requirements for the pulse you can detect anything that isn't made to evade radar, at pretty much whatever range you want.

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Routine_Shine_1921 t1_ixml7qe wrote

No. If you collide with it at 1m/h, then it doesn't bloody matter, that thing is almost in the same orbit as you, and it presents absolutely no threat to your spacecraft.

You care about micrometeoroids when they collide with you at any significant speed, at which point a laser can't do ANYTHING about it.

Unless we turn OP's idea on its head, and instead of trying to do something shield-like with passive lasers, we do an active system with just one laser, and some kind of tracking system that detects potential collisions, and then targets and eliminates those threats at a distance. Which is even more impossible from an energy usage perspective, and the detection and tracking would be insanely difficult.

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