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Comment by KRAKRISMOTT | Hacker News Reader

Not likely. The re entry tech is a critical component of ICBMs. Satellites are relatively easy in comparison, they are just a orbiting computer with a sophisticated radio/signaling processing stack. Most countries can build satellites, but the countries that can put them into orbit are all significant powers. I doubt major powers would be willing to transfer smaller players the technology for controlling re-entry.

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My understanding is most of ICBMs don't go to orbit anyways, mostly because it'd just delay the strike. Why would anything from a suborbital launch be needed to control re-entry?

FOBSs go to orbit.

Lots of satellites have thrusters to stabilize and adjust their orbits. Especially those at lower orbits since they do have to counter the effects of atmospheric drag.

All that's really needed is a convention for those satellites than can, to use the last remaining propellant to perform a de-orbit maneuver.

I think tech for gradual reentries (stuff like electromagnetic tethers) is not useful for ICBMS

The reentry tech in ICBMs has nothing to do with satellite disposal, and, in fact, would make satellite disposal more hazardous (because it would mean the satellite would reenter in one piece rather than breaking up into smaller pieces that are more likely to burn up/melt in the atmosphere).

An ICBM warhead reaches space but at suborbital speeds. It never reaches orbital velocity and will reenter no matter what; it has a heat shield so that the warhead remains intact when descending through the atmosphere.

For satellite disposal, the satellite starts off at orbital velocity and needs to be decelerated above the atmosphere to drop the low point in the orbit far enough that the atmosphere will decelerate it below orbital velocity.

https://what-if.xkcd.com/58/ has a good overview of the difference between suborbital and orbital velocity.

Would it be possible that whoever launches the satellite (in a major power) somehow adds to it a re-entry module, so the knowledge and sensible devices stay out of the reach of lesser powers?

It would take a lot of trust. You can basically stick a bug in there and siphon the radio data (yes there is encryption etc. but you probably don't want another actor's hardware being permanently attached to your satellite, opens up all sorts of vulnerabilities. It's close enough for nearfield attacks like EMP or explosives or even wrong sensor data).

It would make more sense to ensure that any sensitive technology on board is in a demisable subunit that will melt during reentry, so nobody has a chance to snag it after it reenters.

This is also a safety consideration in satellite design - see, for instance: https://spectrum.ieee.org/spacex-claims-to-have-redesigned-i...

If the whole thing comes apart into tiny pieces, you have no chance that anyone/anything on the ground will be injured/damaged by falling debris..

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