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Historical Spaceflight / Re: Apollo 16 -- an odd what-if
« Last post by Kansan52 on Today at 10:43 PM »
My guess is 16 would be cancelled if swaps seemed needed because of fiscal and political policies at the time.
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But, besides the theoretical reasons, there is not a single reproducible experiment where someone has been able to extract energy from the Quantum Vacuum.


Even if one were to set aside the concerns about the experimental claims (i.e. Shawyer has never performed a single experiment in vacuum), and the theoretical problems (with the concept of extracting energy from the QV) explaining the EM Drive with an explanation that itself is the only experiment where someone has been able to extract energy from the Quantum Vacuum sounds like a circular argument.




Well, there is the Universe - it continues to expand, and that expansion is being driven by the energy of the Quantum Vacuum. From that, one would understand that this expansion is then using up energy from the Quantum Vacuum, while increasing Entropy. If we insist that energy cannot be taken from the Quantum Vacuum, then we must also insist that the Universe cannot be expanding, since such expansion requires it.

So just like Voyager depended upon stealing momentum from Jupiter, and like Mach Effect drive depends on stealing momentum from the Rest of the Distant Universe, likewise EMdrive would depend upon stealing momentum from the Quantum Vacuum.

Dr Rodal, I was also eager to hear your comments on what I said in the Woodward Effect thread.   :)

1) It is easy to show that the acceleration claimed by EM Drive proponents is a huge number of orders of magnitude larger than the cosmological constant term responsible for the accelerated expansion of the Universe.

2) It is also straight forward to show that the dark energy acts like a spring, such that the accelerated expansion of the universe is only felt over huge distances: billions of light years, and completely negligible over distances like  the size of the EM Drive. 
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A company can submit up to two proposals, but only one family of vehicles can get chosen according to the documents.  That would mean SpaceX could get funding for either Falcon or BFR family, not both.  I assume the Air Force would lean towards the one that actually exists already.

A fair assumption, no doubt.

I'm torn; BFR could be a boon to all  forms of space access, including military space needs. The AF Space Command is downright enamored with reusable rockets at the moment, and SpaceX will almost certainly submit proposals for both the Falcon family and BFR. FH is definitely the obvious choice given its maturity, but it doesn't look like FH can accomplish all the example missions while recovering all three cores.

I'm sure SpaceX is still somewhat open to expendable missions if there is no alternative, but not 100% sure when we're talking about the '20s. I'd love to see some official numbers on payloads with an expendable center core, but there's also the reality that SpaceX would likely rather recover center cores over side cores.
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But, besides the theoretical reasons, there is not a single reproducible experiment where someone has been able to extract energy from the Quantum Vacuum.


Even if one were to set aside the concerns about the experimental claims (i.e. Shawyer has never performed a single experiment in vacuum), and the theoretical problems (with the concept of extracting energy from the QV) explaining the EM Drive with an explanation that itself is the only experiment where someone has been able to extract energy from the Quantum Vacuum sounds like a circular argument.



Well, there is the Universe - it continues to expand, and that expansion is being driven by the energy of the Quantum Vacuum. From that, one would understand that this expansion is then using up energy from the Quantum Vacuum, while increasing Entropy. If we insist that energy cannot be taken from the Quantum Vacuum, then we must also insist that the Universe cannot be expanding, since such expansion requires it.

So just like Voyager depended upon stealing momentum from Jupiter, and like Mach Effect drive depends on stealing momentum from the Rest of the Distant Universe, likewise EMdrive would depend upon stealing momentum from the Quantum Vacuum.

Dr Rodal, I was also eager to hear your comments on what I said in the Woodward Effect thread.   :)
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Em, this is a bit random, but I was watching a video today about a supposed hypersonic missile that Russia is developing. I have no idea about the veracity of the story, but at 49 seconds in the video it looks like a cut-away of a SABRE engine.

It doesn't just look like a cut-away of a SABRE engine, the guy who made the video has literally just pasted in a cutaway of a SABRE engine. And he says seconds later that the missile is powered by a scramjet, whereas SABRE definitely is not a scramjet. In other words, it's just some guy using a fancy picture to have some nice-looking video material, nothing to do with the real Zircon missile.
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Historical Spaceflight / Re: Apollo 16 -- an odd what-if
« Last post by MATTBLAK on Today at 09:59 PM »
He definitely would have - in the Moon's shadow he'd be fine and in sunlight, could turn the Service Module with it's big structure and propellant tanks toward the Sun. The guys on the surface would have to terminate their EVA if it happened in the middle of one and get back in the LM with only a grab sample from their most recent EVA, stay in their suits and liftoff for rendezvous with the CSM asap.

In James Michener's novel 'Space' just such a thing was dramatized.
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Is there some possibility of a Maxwell's Demon here?

ie. some kind of Quantum Feedback Loop whereby you're able to push off the Vacuum fluctuations in a directionally biased way

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

(so the Dynamic Vacuum would be the external field)
If the Quantum Vacuum is the zero energy point, that means that you should not be able to extract momentum or energy from it, because the momentum/energy gained by the EM Drive would be subtracted from the QV, which contradicts its zero point nature. 

But you are pumping up the Vacuum inside the cavity with RF/microwaves. So the state of the Vacuum inside the cavity is not the same as outside the cavity (the true zero point)

So regarding stealing momentum (asymmetrically), if you're stealing it from a pumped-up vacuum, that's not the same as stealing it from regular zero-point vacuum.
But, besides the theoretical reasons, there is not a single reproducible experiment where someone has been able to extract energy from the Quantum Vacuum.

Even if one were to set aside the concerns about the experimental claims (i.e. Shawyer has never performed a single experiment in vacuum), and the theoretical problems (with the concept of extracting energy from the QV) explaining the EM Drive with an explanation that itself is the only experiment where someone has been able to extract energy from the Quantum Vacuum sounds like a circular argument.  Not compelling  ;)
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Is there some possibility of a Maxwell's Demon here?

ie. some kind of Quantum Feedback Loop whereby you're able to push off the Vacuum fluctuations in a directionally biased way

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

(so the Dynamic Vacuum would be the external field)
If the Quantum Vacuum is the zero energy point, that means that you should not be able to extract momentum or energy from it, because the momentum/energy gained by the EM Drive would be subtracted from the QV, which contradicts its zero point nature. 

But you are pumping up the Vacuum inside the cavity with RF/microwaves. So the state of the Vacuum inside the cavity is not the same as outside the cavity (the true zero point)

So regarding stealing momentum (asymmetrically), if you're stealing it from a pumped-up vacuum, that's not the same as stealing it from regular zero-point vacuum.
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SpaceX General Section / Re: BFS is an SSTO?
« Last post by QuantumG on Today at 09:45 PM »
BFS *is* an SSTO... when launched from Mars, as intended.

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This doesn't particularly make sense. Why spend half a billion dollars to put a space station and propellant depot in such a difficult to reach location? This looks more like is a marketing move with both companies wanting to showcase their capabilities with a pretty video. There was a vaguely similar announcement in 2016 but no actual contracts.

I doubt it will actually happen, not unless new LLO transport options appear. Or maybe it could switch to NRHO and get attached to the DSG instead? What's sad is that a date of 2022 is *too soon* and would race with the power and propulsion bus on EM-2.

If Bigelow is serious then just deploy in LEO alone and go straight for the space tourism market. Two commercial manned spacecraft are becoming operational soon and they're even using the same docking system. Being compatible with both Boeing and SpaceX crew vehicles would help keep costs under control.

Yea...whats the point of having inflatable station orbiting the moon?  It does not go to surface, they arent controlling surface rovers, they aren't housing some great telescope...heck there dont appear to be windows even to see the moon!  So hard to know what the payoff is of this. 

Now if they sent it to the moon surface then i see the point.
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