aupri t1_j57rxip wrote on January 21, 2023 at 12:10 AM

Reply to comment by kelldricked in TIL The famous "rods from god" concept of a space-based weapons system of orbiting tungsten rods was developed by science fiction writer Jerry Pournelle. by BitterFuture

There’s a recent Veritasium video about this where he talks about feasibility and the issue is that you’d need a ton of these in orbit to be able to strike anywhere in a reasonable amount of time. If you have one satellite in orbit loaded with these and it just passed the target zone you have to wait for it to come around the earth again, and it would only cover targets on a thin slice of the globe. You’d need a web of satellites, something like Starlink, but each loaded with really heavy rods, which gets pretty expensive

Nuffsaid98 t1_j5ae6p0 wrote on January 21, 2023 at 3:45 PM

I think you're ignoring orbital mechanics here.

If a satellite is orbiting the Earth at a given speed then anything dropped from it would continue at that speed. You would need to retro thrust to scrub off that speed or factor it in.

In other words, anything dropped from orbit has to fall in a curved path.

Avoiding burnup in the atmosphere dictates the angle of entry.

The payload would be dropped when the satellite is over a completely different part of the Earth, not the target.

If you are firing the weapon at high speed instead of using the gravity well to do the work, you still need to allow for the spin. Also recoil will throw your satellite around.

Not as simple as you might think.

f16f4 t1_j57w2d3 wrote on January 21, 2023 at 12:40 AM

I mean I doubt you’d really need to be able to strike anywhere, just sit the satellites over the countries you’re worried about.

Darrel-Yurychuk t1_j585po3 wrote on January 21, 2023 at 1:55 AM

The only satellites that "sit" over a fixed spot on earth are geostationary satellites are directly over the equator but orbit from such a large height from where nothing can be "dropped" back to earth. So you'd need a constellation of satellites to cover any given spot in the world which may be impractical depending on how much they can be steered.