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[martinuzz]

You know what we need? A God old fashioned alien invasion (a winable one of course).

Lol impossible. Any alien civilization advanced enough to cross the distance between stars to attack the naked ape planet will roflstomp us with ease.

[LordBaal]

I know, but we can get creative and find something. You know, the usual movie stuff, they are not invaders but miners/refugees/survivors of a disaster. Or maybe automated probes not programmed to cope well with anything beyond feral animals?

I know all of those have its own pitfalls, but use your imagination!

[dragdeler]

a

[Starver]

You know what we need? A God old fashioned alien invasion (a winable one of course).

Lol impossible. Any alien civilization advanced enough to cross the distance between stars to attack the naked ape planet will roflstomp us with ease.

Depends upon how trivial their Wifi security is...

[dragdeler]

a

[Iduno]

https://www.nydailynews.com/opinion/ny-oped-biden-plays-hardball-with-black-lives-matter-20211019-37fgfctxorhzpcvvnpf7wqrmh4-story.html

No surprise, but the racist in chief is trying to punish people more harshly for opposing racism.

[Lord Shonus]

If you actually read the article, everything about the case, including the terrorism specification, was decided long before Biden took office. He is nit demanding the specification, and even the author of the article is not claiming he is.

The criticism is that his appointee has not stepped in and overruled the lower prosecutors in charge of the case. This is valid, but is orders of magnitude different from your claim.

[Dorsidwarf]

China's recent hypersonic tests got the US rattled.
Not only their missiles' high velocity is worrisome (8000km/h), also the fact that they are not ballistic missiles, but orbital missiles.
They gain high speed while circling the earth a few times before re-entry.

This is a concern, because most of the US' missile shield and interception technology is based on ballicstic missiles approaching from the northpole side of the earth.
Orbital missiles like the new Chinese hypersonic missile can come from anywhere, making them extremely hard to detect and intercept.

Hmm, issue with orbital missiles that circle earth repeatedly is you're looking at like, 4-5 hours between launch and impact. That's not great for "surprise attack" capability because by the time your first strike hits, the target has obliterated you with an all-counts missile counter attack. I guess that does kinda make them more attractive to a regional hegemon like china that wants to assert its power projection and world-class dangerousness, but without creating a USSR-like fear that they're seriously going to strike first.

[Starver]

The ISS orbits the Earth in 90 minutes. A suitably modern FOBS flight would probably be: a) lower, thus quicker to do so, and b) not expected to do a full orbit[1].

Though I get the impression these are more "hypersonic cruise-missiles" than merely ICBM tracks artificially flattened with additional delta-V added to what could otherwise have been a thousand-km-or-so apogee of a much simpler suborbital arc.

(The air-breathing propulsion-system could be an early part of the ALTO booster system, like the Pegasus or Virgin Orbital platforms, and maybe even retained for further use during the redeorbitted final trajectory phase, but technical requirements might make that more difficult to justify than just scramjetting most of the way in the upper atmosphere.)

[1] Less than half 'direct', the counterpart greater-than-half if taking the long way round, probably closer to half way if planned to launch a limited sneak attack during a known surveillance 'blind spot' period and sending it via the airspace of a convenient potential scapegoat-'beligerant' you are happy to frame/muddy the waters with, at least to deny or defer the blame going immediately upon you. (There are probably better ways to execute such a strike, but while we're considering the ability we are considering, we could at least suggest some further misdirection measures.)

[Dorsidwarf]

The ISS orbits the Earth in 90 minutes. A suitably modern FOBS flight would probably be: a) lower, thus quicker to do so, and b) not expected to do a full orbit[1].

Though I get the impression these are more "hypersonic cruise-missiles" than merely ICBM tracks artificially flattened with additional delta-V added to what could otherwise have been a thousand-km-or-so apogee of a much simpler suborbital arc.

(The air-breathing propulsion-system could be an early part of the ALTO booster system, like the Pegasus or Virgin Orbital platforms, and maybe even retained for further use during the redeorbitted final trajectory phase, but technical requirements might make that more difficult to justify than just scramjetting most of the way in the upper atmosphere.)

[1] Less than half 'direct', the counterpart greater-than-half if taking the long way round, probably closer to half way if planned to launch a limited sneak attack during a known surveillance 'blind spot' period and sending it via the airspace of a convenient potential scapegoat-'beligerant' you are happy to frame/muddy the waters with, at least to deny or defer the blame going immediately upon you. (There are probably better ways to execute such a strike, but while we're considering the ability we are considering, we could at least suggest some further misdirection measures.)

Yeah but the concept I was responding to was explicitly "Multiple orbits before re-entry".

[martinuzz]

Yeah, at least that's what my newspaper article said.

Doesn't make them any easier to detect though, detecting small, fast objects in orbit realtime is quite hard.

[Starver]

Yeah but the concept I was responding to was explicitly "Multiple orbits before re-entry".

Apologies, but it's so obvious that this is a bad idea for a launch system[1] even vs. the logical (treaty-breaking) alternative[2] that I read it all as an error in describing the FOBS approach[3]. Sorry, clearly my wrong assumption.

Swarm attacks might be hard to do without come-back (too much chance of launch detection, or piecing it together afterwards) and even targetted attacks (Earth-observation satellite, still connected to its partially fuel-filled upper-stage, just happens to malfunction and deorbit without burning up so as to land on another country's seat of power?), but those problems would also exist in atmosphere-only cruise-style delivery systems, even/especially at high-Machs. (Maybe you could steer those to appear they're popping up from a scapegoat "enemy's enemy" territory, or even contrive to suggest the E's E had done the same to yourself, just to delay retaliation until it doesn't matter any more.)

With whatever it is that is the Chinese system, with China's position, I'm not saying they'd try obfuscation (contrive to blame Iran?) and it'd probably be more useful as "We back our words with uninterceptable NUCLEAR WEAPONS!" than anything of a first-/second-strike actuality ("The only winning move is not to play..."). Possibly some machiovellian plans might involve a US overseas/on-the-seas resource disappearing in an 'accident', that is not easy to investigate, but you couldn't expect a carrier group to not spot a hypermach bogey incoming and without at least some ability to instantly report this to home.

But if it raises from a capability to being seriously considered for use (beyond mere just-in-case preparation) we're already well beyond a political/military sanity that I'd feel comfortable attempting too much precogniscence upon.



[1] Press the button, at a time of great tension, to send your single/multiple warhead-carriers up for a limited number of whole orbits before landing - all the while being tracked.

[2] Sending up an 'innocent' satellite up as 'routine', even to look like a spysat, that orbits for indeterminate amount of peacetime then suddenly acts as a launch-platform (and/or de-orbits its whole self) as and when "the button is pressed".

[3] "Press button" to launch to orbit, in anger, preconfigured with no intention to complete that orbit but instead re-enter just in time to surprise the target - or at least get through gaps in any of the now alerted defensive measures.

[martinuzz]

Yeah, the article mentioned it being a hypersonic FOBS.
The Chinese test was a glider craft launched into low orbit, circling the earth, and then re-entering space shuttle style.
It missed it's target by some tens of kilometers though.

[Starver]

Shallow entry at orbital-like re-entry velocities is always going to be tricky. Local atmospheric changes can extend the overshoot/undershoot window (probably beyond passive aerofoil adjustment[1]). Perhaps spare thrust/retrothrust could help[2], but not without adding some new risk of interception[3].

Independent of a willing target site there's also a lot of necessary self-reliance on a vehicle working out itself how to apply such changes as well. They could have cheated a bit on the test, but it wouldn't prove as much. And, just like they got the first Shuttle landing's aerodynamic predictions wrong (based upon the Real (Equilibrium) Gas Model rather than a more complex Real (Non-Equilibrium) Gas Model) there's probably a few things to learn - and if it didn't start tumbling and destroy itself in mid-aid in trying to over-adjust then it's probably a good first test.
 

(Ballistic trajectories via space have far less passage time in the atmosphere, and not as oblique. Still not trivial, but tried and tested by most of the capabilities in this field.)


[1] The Shuttle took the opportunity to do turns, to ensure they reach the runway but also adjust the slack. Does destroy the element of surprise, though.

[2] SpaceX's platform is using that, which means flipping from the 'dynamic flappy deceleration/attitude control', but we've yet to see a full orbit-to-tower-catch accuracy of landing, as clearly desired.

[3] Deliberate aiming-off would be possible to misdirect, knowing that it could be recorrected, but cuts down on the available adjustment of non-deliberate drift going further in the wrong direction.

[MaxTheFox]

I will probably regret looking at this thread again but as long as it's not Trump supporter genocide (yes many of them are bad people but still) I'm fine.

There is no way an alien invasion would be repelled by humans. An interstellar species, as martinuzzz said, would have technology beyond our comprehension. Honestly if they don't want to genocide/enslave us I'd just surrender immediately rather than lose possibly billions of lives. If it's like an automated probe that's nevertheless hostile, disable it in a way as harmless as possible and dissect it for tech.

Joe Biden just promised to defend Taiwan if China attacks it. In an interview with CNN, he stated that he feels an obligation to do so.

Based.