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Unmanned U.S. Air Force space plane lands after secret, two-year mission

reuters.com

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Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission

#131

Post by pavement »

nradov wrote: post #111
mdorazio wrote: post #95

Earlier quoted context omitted.

I think you're forgetting a number of advantages. 1. Surprise. All land-based launch sites are actively monitored all the time, giving countries advance warning when a missile is launched. Submarine launches cut down this warning time, but still light up radar and thermal all over the place. A kinetic impactor falling from LEO can hit its target before the enemy even reports up the chain of command (we're talking sin…

No that's all wrong. Firing a missile from orbit has less surprise value than firing from a submarine because satellites can't hide. There's no difference in kinetic effects; a non-nuclear ballistic missile can hit just as hard at a lower cost (do the math). A kinetic projectile launched from a satellite is no harder to intercept than a ballistic missile in the terminal phase, and satellites themselves are highly vul…

Kinetic impactors are not missiles. Repeat: Kinetic impactors are not missiles.

https://en.wikipedia.org/wiki/Kinetic_bombardment

These are not things that get fired. You don't launch them.

They don't follow a trajectory. They might just travel straight down from a geostationary orbit, depending on implementation. Yes, a guidance package might be necessary (depending on target discrimination, and precision, which in warfare isn't always required). They aren't gliding like smart bombs though.

At the speed of re-entry, and with possibly just 100 short miles to close, a defensive interceptor would be unwarned, have to acquire possibly many targets (one need not drop only one). Intercepting vehicles would have to close on a target in an arc representing a distance longer than the hypotenuse of the right triangle between the kinetic slug, the interceptor's launch site, and the defended target.

The slug is simply released with no indication of ingress. From a geostationary orbit, it just starts getting closer very fast. Cover it with EM absorbant, non-reflective material, and there's even less hint of activity, until the re-entry burn at approximately 60 miles altitude. Unless the target itself is equipped with interceptors, and lots of them, it will be difficult to notice and recognize in time, and even harder to catch and defeat.

Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission

#132

Post by vl »

nradov wrote: post #79
tammer wrote: post #20

Surprised nobody's mentioned this possibility as it usually comes up re: the X-37B. Terrifying but I think not out of the question given the strategic potential of such a weapon. https://en.wikipedia.org/wiki/Kinetic_bombardment

Orbital kinetic bombardment is a silly concept suitable only for cheap sci-fi novels. There's no benefit in having kinetic weapons permanently positioned in orbit. The satellites would be easily tracked and vulnerable to ASAT weapons. They can't strike a target much faster than a ballistic missile launched from land or sea. And they would be much more expensive. Anything in orbit is out of reach of maintenance. It ta…

The main problem is that even 500kg at sub-7 km/s doesn't deliver that much energy. Conventional weapon of the same mass is way more effective (and this is why ICBMs now can deliver conventional warheads).

Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission

#133

Post by kobeya »

dotancohen wrote: post #119
kobeya wrote: post #86

Earlier quoted context omitted.

No, powered landings all the way down. At least on the Moon and Mars (from orbit). With more fuel you could do the same from Earth, but why bother?

Are you sure about the orbit? Could a Red Dragon not land directly from a Hohmann transfer?

It could land directly, yes, but it makes use of the aerobrake for slow-down. Without that aerobrake it would not have enough fuel to do a powered landing all the way down and then return to orbit (I think -- I don't actually work for SpaceX; I'm just a fan). But it is my understanding that it has enough fuel to do a full propulsive landing from orbit and back again, without an aerobrake.

Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission

#134

Post by rocqua »

pavement wrote: post #131
nradov wrote: post #111

Earlier quoted context omitted.

No that's all wrong. Firing a missile from orbit has less surprise value than firing from a submarine because satellites can't hide. There's no difference in kinetic effects; a non-nuclear ballistic missile can hit just as hard at a lower cost (do the math). A kinetic projectile launched from a satellite is no harder to intercept than a ballistic missile in the terminal phase, and satellites themselves are highly vul…

Kinetic impactors are not missiles. Repeat: Kinetic impactors are not missiles. https://en.wikipedia.org/wiki/Kinetic_bombardment These are not things that get fired. You don't launch them. They don't follow a trajectory. They might just travel straight down from a geostationary orbit, depending on implementation. Yes, a guidance package might be necessary (depending on target discrimination, and precision, which in…

> They don't follow a trajectory. They might just travel straight down from a geostationary orbit

That's not how orbiting works. If you want your projectile to travel straight down, you need to cancel all it's orbital velocity. For geostationary orbit, that's 3km/s of delta V needed.

Obviously, you can de-orbit with less delta-V, but then guidance starts becoming necessary.

> The slug is simply released with no indication of ingress. From a geostationary orbit, it just starts getting closer very fast. Cover it with EM absorbant, non-reflective material, and there's even less hint of activity, until the re-entry burn at approximately 60 miles altitude.

There is going to be some kind of burn to start de-orbit, you could simply monitor for that.

Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission

#135

Post by rocqua »

ceejayoz wrote: post #43
gibsjose wrote: post #18

Earlier quoted context omitted.

On-orbit satellite servicing and refueling has not been performed as of yet, but we are currently working on it: https://sspd.gsfc.nasa.gov/restore-l.html

> On-orbit satellite servicing and refueling has not been performed as of yet Declassified on-orbit satellite servicing and refueling has not been performed as of yet. I wouldn't be shocked if the X-37 has refueled a NRO bird or two (or just simulated it) as a test.

Wouldn't those that try to track satellites notice this?

Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission

#137

Post by ntelson1s »

compton_effect wrote: post #39
tammer wrote: post #20

Surprised nobody's mentioned this possibility as it usually comes up re: the X-37B. Terrifying but I think not out of the question given the strategic potential of such a weapon. https://en.wikipedia.org/wiki/Kinetic_bombardment

cool idea but I'm gonna assume its a lot more expensive to send up an X-37 and have it crash back down then it is too just send a few nukes at your target.

What nobody seems to be mentioning here is that under treaties, and especially the space treaties in effect, a kinetic bombardment follows all the guidelines and is completely allowed, while still potentially having the effects of a nuclear yield, especially pertaining to bunker busting.

Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission

#139

Post by alkonaut »

trothamel wrote: post #59
jessaustin wrote: post #48

Earlier quoted context omitted.

If the satellite has "local" sensing equipment, then sure there's nowhere to hide. How many satellites have that? If such sensors aren't installed, it's not like anyone down here on the ground will notice. If someone did notice, what could they do in response? Complain to the media?

Actually, it's pretty easy to keep track of the X-37. You could see where it would have been had it not landed here: http://www.heavens-above.com/orbit.aspx?satid=40651&lat=0&ln... If it was to get close to a non-US military satellite, one could expect people to complain diplomatically, at least.

If you wanted to rendezvous with a foreign spy satellite (I have no idea why you would) you couldn't do it in a huge space plane because diplomacy. You'd have to send a tiny non-trackable interceptor thing. If you needed a vehicle to deploy such things from, then perhaps the X-37 would make sense.

Re: Unmanned U.S. Air Force space plane lands after secret, two-year mission

#140

Post by daemin »

nradov wrote: post #77
mapt wrote: post #66

Earlier quoted context omitted.

The driving requirement of the Shuttle was that it should be feasible to steal a Soviet satellite sporting unknown new orbital technology, before the Soviets had the opportunity to intervene, and that it be prepared to fly fairly quickly whatever its faults to be ready for potential Soviet expansions into spaceflight as an area of competition. There were a lot of other requirements and stakeholders that were part of…

That's completely wrong. There was no serious consideration of stealing Soviet satellites. Everyone knew that we'd never be able to get away with that. The driving requirement was to act as a successor to the SR-71. Launch, make a single reconnaissance pass over the Soviet Union, and then utilize the cross-range capability to land immediately so that the film could be developed. But by the time the Shuttle was actual…

If the Russian satellite is a secret, and the Americans steal it secretly, then of course they would get away with it. It's like a thief stealing from another thief.
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