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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

#111

Post by nradov »

mdorazio wrote: post #95
nradov wrote: post #79

Earlier quoted context omitted.

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…

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 vulnerable. A big chunk of mass landing near a target won't have much effect. And the projectiles couldn't be just rods. Due to the variability in rockets used for de-orbit burns as well as atmospheric conditions they would need fragile and sensitive guidance packages.

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

#112

Post by knz »

mdorazio wrote: post #97
taneq wrote: post #65

Earlier quoted context omitted.

People always talk about kinetic strikes in the context of big flashy things like rockets and spaceplanes. I'd be a lot more worried about them being dropped from stratospheric balloons - maybe not so useful for full scale bunker busting but extremely cheap to make and almost indefensible against as a strategic strike system.

This reminds me of a novel weapon from the Daemon novels. Basically, small semi-guided darts dropped from weather balloons that were used as antipersonnel weapons rather than as a replacement for conventional explosives.

https://en.m.wikipedia.org/wiki/Flechette and https://en.m.wikipedia.org/wiki/Lazy_Dog_(bomb)

Something similar has already been used here since​ WW1.

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

#113

Post by sandworm101 »

gibsjose wrote: post #104
sandworm101 wrote: post #54

Earlier quoted context omitted.

Refuelling sats won't ever be a thing. There is no real need. Any refuelling vehicle will need it's own propulsion/rcs system and a docking scheme. Once docked and/or latched onto the target ... job done. The refuelling vessel becomes the new orbital manoeuvring system for the depleted sat. Cost wise, that makes more sense than having a large tanker bouncing around between clients. With the switch to ion propulsion t…

Refueling satellites will absolutely be a thing :) Restore-L is going to do just that in 2020-2021, and do it autonomously to boot. I work on Restore-L and believe me, there is a huge need for on-orbit satellite refueling and reservicing. The vast majority of satellites reach their end of life due to depletion of fuel, not due to electrical problems or sensor issues. This will be a huge business one day.

But will sats be refueled or will they simply have new service modules attached to them, bypassing all the tricky plumbing issues?

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

#114

Post by dingaling »

jjoonathan wrote: post #108
dpc59 wrote: post #78

Earlier quoted context omitted.

The ressources required to shoot stuff that's in the stratosphere are on a whole other ballpark than what your average revolutionaries can do.

Intercepting stratospheric balloons is child's play, possibly literally, compared to intercepting chunks of metal flying at 10km/s, which are the alternatives under discussion. > I'd be a lot more worried about them being dropped from stratospheric balloons - maybe not so useful for full scale bunker busting but extremely cheap to make and almost indefensible against as a strategic strike system. If you meant to spea…

The Soviet Union spent 40+ years, and many pilots' lives, trying to devise a means of destroying CIA balloons operating at 30km altitude. SAMs, AAMs, artillery and even ramming all mostly failed.

Eventually by the late 1980s they developed the Myasishchev M-17 balloon interceptor aircraft, with a dorsal cannon-turret and able to loiter for hours at 22km. Still not quite sufficient.

Now increase the balloon altitude to 50km and they should be safe against any opposing force with early-2000s levels of military capability.

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

#115

Post by zipwitch »

knz wrote: post #110
dogma1138 wrote: post #55

Earlier quoted context omitted.

Look at the payload capacity of the X37 it would do about as much damage as a bunker buster.

If the X37 is public they probably have something bigger and better tucked away in a hanger somewhere remote. Think about how long the F-117, SR-71, U-2, B-2, or RQ-170 were kept secret. There is no way they haven't thought about how to use this in a military capacity.

If they do, it's almost certainly never been put into orbit. The guys who track satellites as a hobby are good.

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

#116

Post by njarboe »

blackguardx wrote: post #99
jessriedel wrote: post #94

Earlier quoted context omitted.

> Not using fuel while landing saves precious cargo capacity Those wings are also a lot of mass, and hence take away from payload. In fact, propulsive landing always takes less mass than wings in the limit of large craft size. (You can see this by taking an equivalent limit, the limit of thin atmosphere; for sufficiently thin atmosphere, the amount of surface area you need to brake diverges but the amount of fuel to…

I won't argue with that, but that isn't true in the case of the X-37, which is why it glides into landing. Elegance in engineering is fulfilling the requirements in the simplest, cheapest way possible.

Following this principle I sometimes think the new east span of the Bay Bridge is/was a $6 billion boondoggle. The historical (and I thought, beautiful) original span was not retrofitted because Caltrans said they could build a new span for less that would have a longer lifespan. The simple, cost effective viaduct design was rejected as not grand enough for a Bay Area bridge and a short decorative, self-anchored suspension bridge was added to the viaduct for an extra $5 billion. It would sure have been nice if that money had been spent on a couple of additional bridges across the bay. One from the 101/380 to the 880 near the Oakland airport would sure help the traffic problems some. With interest rates near zero, I'm sure the finances for a toll bridge would work out. Just need the political will.

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

#117

Post by knz »

zipwitch wrote: post #115
knz wrote: post #110

Earlier quoted context omitted.

If the X37 is public they probably have something bigger and better tucked away in a hanger somewhere remote. Think about how long the F-117, SR-71, U-2, B-2, or RQ-170 were kept secret. There is no way they haven't thought about how to use this in a military capacity.

If they do, it's almost certainly never been put into orbit. The guys who track satellites as a hobby are good .

For sure. I've read that the RQ-170 was seen quite quickly by plane spotters - likewise with the planes used for extraordinary rendition.

Never underestimate passionate nerds and their ability to notice unusual things!

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

#119

Post by dotancohen »

kobeya wrote: post #86
hughes wrote: post #67

Earlier quoted context omitted.

Powered landings after an intense atmospheric deceleration.

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?

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

#120

Post by colechristensen »

sandworm101 wrote: post #113
gibsjose wrote: post #104

Earlier quoted context omitted.

Refueling satellites will absolutely be a thing :) Restore-L is going to do just that in 2020-2021, and do it autonomously to boot. I work on Restore-L and believe me, there is a huge need for on-orbit satellite refueling and reservicing. The vast majority of satellites reach their end of life due to depletion of fuel, not due to electrical problems or sensor issues. This will be a huge business one day.

But will sats be refueled or will they simply have new service modules attached to them, bypassing all the tricky plumbing issues?

They will be refueled.

https://sspd.gsfc.nasa.gov/restore-l.html

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