Rods from god, how are they “dropped” from orbit?


Veritasium recently did a video on this subject, not one of his best, about objects “dropped” from orbit as a weapon with a high destructive potential. The destructive part is easy enough to understand, but I don’t get how the objects would be released and “fall” from an orbiting platform. Wouldn’t the rods just continue to orbit? To make them fall, you’d have to cancel out all or most of the orbital velocity. If you just fired them downwards, they’d still go sideways and you’d have a harder time aiming them. What am I missing?

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8 Answers

Anonymous 0 Comments

Yeah you would have to fire them backward with some rockets. You wouldn’t have to cancel out all the orbital velocity necessarily, the things could enter the atmosphere at a pretty decent angle but yeah. Definitely can’t just ‘drop’ one straight down.

Anonymous 0 Comments

You’re not missing anything, those are just a concept weapon designed by never made as it’s not worth it for reasons you stated (expensive to get them to space, expensive to keep there until you need them, once you need them, they’re kinda hard to aim accurately (which probably wouldn’t matter since the crater they’d leave would be so big) )…

But the idea is gravity would just pull them down (as far as i remember)

Anonymous 0 Comments

These don’t actually exist and the details about their design would be confidential, so there isn’t a lot of info available about them. However, there would likely be some set of thrusters on the satellite and/or rods to ensure that the rods get pushed out of the satellite in the proper direction. The rods wouldn’t need to go straight down; they’d just need to fall at an angle where their downward movement combined with their momentum from the orbit results in them falling on the proper target.

Anonymous 0 Comments

Orbits have to be maintained through some type of Rocket or thruster.

An orbital drop kinetic bombardment weapon would have neither thrusters nor Rockets so as soon as it detaches from the object that it’s launched from its orbit will begin to decay.

Figuring out when and where to release it and calculating the orbital Decay is how you would aim the weapon

Anonymous 0 Comments

Either they are in a low orbit, in which case you really don’t need to cancel that much of their velocity, or they are in a high orbit and they pick up a ton of speed from falling.

The ISS orbits close to Earth at 420km. It moves at 7660 m/s. To drop its ~~apogee~~ perigee to ground, it would have to slow to 7530 m/s. By the time it reaches ground, barring any air in its way, it will be moving at 8030 m/s.

It will have *more* energy, despite slowing down.

Anonymous 0 Comments

You’re right that they’d just stay in orbit. If they’re in a low orbit then atmospheric drag will slow them down eventually, but rods from god are useless if you need to plan where it’ll hit a decade in advance so you need something that can abruptly force it into a suborbital trajectory

There are a couple potential options. Most straightforward is to have a rocket fire in the opposite direction of the orbit to slow it down and drop it down. This one still has a bit of lag time to it

Other option is to fire it downwards *hard* either with a rocket or a magnetic launcher like a coilgun. If you launch it down at a few hundred meters per second it’ll pretty quickly get deep in the atmosphere and burn off it’s orbital velocity so it doesn’t pop back up a half orbit later. Downside, still super hard to aim so it’d likely need a continuously burning rocket engine to provide terminal guidance so yet more mass included in orbit

Anonymous 0 Comments

All the satellites we have are probably much closer to earth than you are expecting. In fact they are already all falling and it requires thrusters to realign them to keep them from a degrading orbit. To drop a rod you would simply unlatch it in a mathematically prudent angle and let gravity pull it in. With out thrusters gravity would pull in our satellites as well.

Anonymous 0 Comments

> To make them fall, you’d have to cancel out all or most of the orbital velocity.

Bingo. You would deorbit them the same way you would deorbit a space capsule or the second stage of a rocket for example. They no longer have enough speed to stay in orbit so they fall back to Earth.