As I recall, this was more or less the concept behind Brilliant Pebbles [0], except Starship makes it cost-effective to launch.
I'm not going to argue whether building it is a good idea, but it also seems like Starship has the potential to make launching a kinetic bombardment system [1] possible given the large payload capacity.
The brilliant pebbles were supposed to be stationed in orbit. What I'm talking about is simply an upgrade of the current ground based missile defense. The immense capacity of the Starship makes this possible. It also completely reverses the old cost calculus of offsense-defense in the ICBM space: in the past you could simply counteract an attempt at a comprehensive missile defense system by building one thousand more ICBMs, and if that was not enough, two thousand or ten thousand. It was cheaper to add one more ICBM than to add the capability to stop it.
In the near future that will stop being the case. The ICBM has to have, after all, a nuke, and a nuke will never be very cheap. The kill vehicle is simply a block of steel, or some other metal. A maneuverable one, but still, a much cheaper piece of equipment than a nuclear warhead. By the way, the fancy term for the nuclear warhead is "reentry vehicle", and, as the name implies, it has to be build to withstand the tremendous shocks of reentering the atmosphere. Not so with a kill vehicle: if it needs to reenter the atmosphere it means it failed to do its job and it's not needed anymore.
Of course, Russia and China have seen the writing on the wall, and that's why they started looking for alternate ways of delivering nukes. I'm talking here about hypersonic, nuclear capable, weapons.
Regardless, my point is that in the near future, SpaceX will get some eye-popping contracts from the Pentagon, and specifically for missile defense reasons.
Are you saying that there will be a large number of Starships on duty for immediate launch to deploy kill vehicles over an arbitrary area in space over and around the US? I'm no expert but this sounds pretty different form what Starship is designed to do. And not cheap at all.
I think u/credit_guy means that with Starship the U.S. could put a constellation of anti-missile missiles in orbit and keep them there for the long haul. If Falcon 9 can put up 5,500 sats in a few years, Starship could greatly increase the rate at which the U.S. can build not just comms constellations but also reconnaissance ("spy") constellations, missile defense constellations, anti-sat constellations, maybe even nuke constellations, who knows.
I suspect that missile defense constellations would have to be truly gargantuan though, because of some N thousand missile defense sats most will not be able to reach the missiles being launched at any given point, thus to counter a 1,000 ICBM/SLBM threat the missile def constellation might have to have 20x -maybe even 100x- that many space-launched anti-missile missiles. That seems prohibitively expensive even if internal Starship launch costs ever come down below $5 million each.
> The brilliant pebbles were supposed to be stationed in orbit. What I'm talking about is simply an upgrade of the current ground based missile defense
How would that work?
Starship uses cryogenic fuel, and thus isn't something you can keep on active standby for years at a time, ready to be launched with a few minutes notice. It takes hours for a Starship to be loaded with liquid oxygen and prepared for launch. By the time you finished getting it ready for launch, it would have been nuked by the other side's second wave.
The only way Starship could be practically useful for missile defense is by launching some kind of defense system stationed in orbit.
Kinetic bombardment is possible by launching a satellite with (for example, since its a popular description) heavy tungsten rods, that are parked in orbit. The launch can be years ahead, and disguised as a communications hub.
The satellite can “shoot” at targets from orbit. A rod carries no explosives, and is hard to stop.
The speed due to falling/gravity makes the kinetic impacts huge, its basically small asteroids.
They can even be guided, like the landing boosters.
And to go full circle: the concept of aero-flaps on Falcon-9 (and later Starship Booster) was inspired by designs for falling guided bombs, where fins did not perform at the speeds achieved.
The stated goal for the Starship is to be able to go to orbit and come back and then refuel and do another round trip within the same day. Sometimes twice a day. And to keep doing that for a long period of time.
Compared to that, just keeping a Starship fueled for a long period of time, then emptying it, performing various checks, and refueling it for another period of duty seems quite mild.
Space-based interceptor missiles would have their own propulsion. You could lift to orbit, I don't know, 500 of them at a time with Starship—but each of them would need their own, individual, storable propulsion systems to do their function, which is intercepting.
LEO mega constellations are the future of space militarization. NRO + Space Development Agency is relentlessly moving ahead here with Starshield, next gen recon programs and missile tracking layers.
Anyone who isn’t aggressively building production facilities to churn out tens of thousands of LEO satellites and the rockets necessary to launch them (ideally reusable rockets), and developing civilian commercial use cases from telecommunications to ADAS to spread some of the costs, might as well by living in the 2010s still.
Ideally reusable? I think given that SpaceX are now basically guaranteed to provide 100% reusability for the US, anyone trying to keep up, to even remotely match their capabilities, without reusability, will basically bankrupt themselves. I.e. falling in the same trap the Soviet Union did vs USA during the Cold War.
In other words: if a country wants to play this game, reusability is a hard requirement.
In the near future that will stop being the case. The ICBM has to have, after all, a nuke, and a nuke will never be very cheap. The kill vehicle is simply a block of steel, or some other metal. A maneuverable one, but still, a much cheaper piece of equipment than a nuclear warhead. By the way, the fancy term for the nuclear warhead is "reentry vehicle", and, as the name implies, it has to be build to withstand the tremendous shocks of reentering the atmosphere. Not so with a kill vehicle: if it needs to reenter the atmosphere it means it failed to do its job and it's not needed anymore.
Of course, Russia and China have seen the writing on the wall, and that's why they started looking for alternate ways of delivering nukes. I'm talking here about hypersonic, nuclear capable, weapons.
Regardless, my point is that in the near future, SpaceX will get some eye-popping contracts from the Pentagon, and specifically for missile defense reasons.