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The "Real Aerospace" Thread 
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Post Re: The "Real Aerospace" Thread
icekatze wrote:
hi hi

I'll have to hunt down the article again, but I remember reading a little piece once about how spinning up rocky asteroids for gravity will potentially cause them to break apart. Probably not impossible to make it work, but could involve some interesting engineering challenges.
I meant in the sense of using a rocky asteroid as the source of the materials that you process and assemble into a habitat station, not in the sense of digging a cave in it and using it directly. After all, a lot of rocky asteroids are thought to just be rubble piles, so they won't even hold an atmosphere if you dig wrong. The main reason to use a rocky asteroid instead of a metallic one is that you can use the silicon-based rocks as radiation shielding (which doesn't need to spin, but which you'll build to stand some acceleration regardless).

icekatze wrote:
As for myself, I expect that if we ever do manage to colonize space, it will at first be incidental. Habitats will pop up around whatever industry we manage to first operate in space, and will go from there. Whether that's on another planet or one of those insanely rich asteroids, I suppose it could go either way. Unfortunately, as it stands, the people with the money and wealth to personally fund space colonization are the ones who have the best living arrangements on the entire face of the Earth already.
Several of them actually want to see it happen though, and that is what will eventually make it possible for everyone else.


Sat Jan 09, 2016 9:55 pm
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Post Re: The "Real Aerospace" Thread
SpaceX launched a Dragon ISS supply mission today and stuck the experimental landing of the Falcon first stage booster at sea on an automated barge named Of Course I Still Love You.



(Click this link for the moment of landing)
https://youtu.be/7pUAydjne5M?t=1647

It's still fun to hear the crowd of SpaceX employees going absolutely berserk as if they're watching a rock concert.

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Sat Apr 09, 2016 2:27 am
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Post Re: The "Real Aerospace" Thread
They act like they get a raise or extra vacation day each time a first stage makes a succesful return. :lol:

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Sat Apr 09, 2016 11:49 am
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Post Re: The "Real Aerospace" Thread
https://www.theguardian.com/science/201 ... tar-voyage

$100 million for Breakthrough: Starshot. Build a giant laser and melt propel a child's kite (sized) sail to high velocity carrying a microchip sized package to distant locales.


Still waiting on Breakthrough: Lunar Resourcing or Breakthrough: Orbital Manufacturing.


Wed Apr 13, 2016 9:11 am
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Post Re: The "Real Aerospace" Thread
Orbital manufacturing probably depends on metal 3D printing (as a bootstrap technology, not as the main implementation), and exo-Earth resourcing.

At any rate, the only real barrier to Lunar resourcing is someone putting up the money. Even I know how to do it, and I'm neither metalurgist, nor chemist (see, you start with aluminum, because the only basic purposes it isn't useful for are ones you need to bootstrap towards anyways...).


Wed Apr 13, 2016 4:17 pm
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Post Re: The "Real Aerospace" Thread
SpaceX stuck another Falcon booster landing on the barge Of Course I Still Love You, this time from a much higher peak velocity (the JSAT payload being launched into a Geostationary Transfer Orbit).



https://youtu.be/L0bMeDj76ig?t=28m22s

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Fri May 06, 2016 4:02 pm
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Post Re: The "Real Aerospace" Thread
Looks like they have roughly a launch each month?

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Sat May 07, 2016 2:27 pm
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Post Re: The "Real Aerospace" Thread
Arioch wrote:
SpaceX stuck another Falcon booster landing on the barge Of Course I Still Love You, this time from a much higher peak velocity (the JSAT payload being launched into a Geostationary Transfer Orbit).


Note that due to the low margins available for landing, this one did a ballistic arc to reentry with no boost-back burn, taking it 650 km down-range, and it did a 3-engine landing burn to reduce gravity losses. It's not clear to me exactly when the engines burned or what their throttle settings were, but it looks like the stage was supersonic about 5 seconds before landing.

GeoModder wrote:
Looks like they have roughly a launch each month?


Their target is 18 launches this year, with a cadence of 1 launch every 2 weeks by the end of the year.


Mon May 09, 2016 3:23 pm
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Post Re: The "Real Aerospace" Thread
Mjolnir wrote:
It's not clear to me exactly when the engines burned or what their throttle settings were, but it looks like the stage was supersonic about 5 seconds before landing.
That sound like a rather energetic landing.


Mon May 09, 2016 8:51 pm
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Post Re: The "Real Aerospace" Thread
Better video of the landing now available, three separate angles: https://www.youtube.com/watch?v=LHqLz9ni0Bo

Judging from the lighting, the overall burn took roughly 10-15 seconds. I'm pretty sure the three-engine segment couldn't take more than a few seconds of that, or it would have reversed direction before reaching the ASDS (that, or it was coming in at closer to Mach 2-3). I'm guessing it lit up the center engine at low throttle to provide some more control and then fired the side engines for a short braking burn before landing on the center engine as usual. Unfortunately, I don't think there was any aircraft watching this one from a distance.

Also, the Merlins can now throttle down to 40%, an improvement over the earlier 70%. Not record setting or anything, but a nice increase in margin for correcting errors during descent.


Tue May 10, 2016 4:36 am
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Post Re: The "Real Aerospace" Thread
This isn't aerospace exactly, but it's some pretty amazing high-tech fabrication.



http://carbon3d.com/

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Mon May 16, 2016 6:28 pm
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Post Re: The "Real Aerospace" Thread
Arioch wrote:
This isn't aerospace exactly, but it's some pretty amazing high-tech fabrication.

[snip]

http://carbon3d.com/
Looks to me like all that's left is cheap metal deposition, and stewart-platform mounted multi-extruder printer designs.


Mon May 16, 2016 8:24 pm
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Post Re: The "Real Aerospace" Thread
SpaceX is starting to make this look easy: https://www.youtube.com/watch?v=4jEz03Z8azc
Another satellite sent on its way to GEO, another first stage brought back, this time with video from the stage on the way in. This one omitted the boostback burn again, and probably was another three-engine landing. It also apparently landed a bit hard, and used up all the crushable shock absorbing material in the legs.

And after some initial trouble, NASA's slowly expanding the Bigelow module that was attached to the ISS a month ago. From what I've heard, it sounds like the issues are down to it being a smaller-scale article that was kept packed for 15 months instead of the 5 months it was designed for. Watching it is about as exciting as watching grass grow, and NASA seems to want to do as little as possible with it before throwing it away, but it's a major step forward in habitat technology, and it's nice to see some movement on it again...it's been a while since the Genesis modules were launched.


Sat May 28, 2016 2:14 pm
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Post Re: The "Real Aerospace" Thread
The Juno probe performs its orbital insertion maneuver on July 4.


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Post Re: The "Real Aerospace" Thread
Arioch wrote:
The Juno probe performs its orbital insertion maneuver on July 4.



Damn, it must feel cool to be a rocket scientist. They're really hamming it up, though, like they're sending humans on a prototype FTL jump.


Tue Jun 28, 2016 10:09 pm
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Post Re: The "Real Aerospace" Thread
Read an interessting article about the so called "Em-Drive". Unfortunatelly it was in German.
Nevertheless, the paper it was based on, can be found here: Link
I guess someone here might find it interessting.

A google translated version of the German article I mentioned: Link

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Thu Jun 30, 2016 8:35 am
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Post Re: The "Real Aerospace" Thread
hi hi

Judging from the article, they ran some tests and didn't find any evidence one way or another. Although, a likely culprit emerges, in the form of an electromagnetic field from the microwave's power source.


Thu Jun 30, 2016 9:29 am
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Post Re: The "Real Aerospace" Thread
icekatze wrote:
Judging from the article, they ran some tests and didn't find any evidence one way or another.
And this, ladies and gentleman, is how we know it was an EM-Drive test! Seriously, every actual EM-Drive test ever.

icekatze wrote:
Although, a likely culprit emerges, in the form of an electromagnetic field from the microwave's power source.
If that's the actual source it'll be a bit disappointing, though not too surprising: the idea of getting usable mass dilation from just charging some ordinary capacitors was always a little odd, so any vaguely related experiments seemed questionable too. At any rate, the big ruccus in the scientific community wasn't quite that it might have worked, but instead that they thought the thrust was too high for the energy input: it had higher thrust than the equivalent photonic drive, which is assumed to require "hidden energy", e.g. via propellant.

Though someone did supposedly come up with a theory that accurately describes the thrust, so maybe that'll go somewhere.


Thu Jun 30, 2016 7:43 pm
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Post Re: The "Real Aerospace" Thread
Absalom wrote:
icekatze wrote:
Judging from the article, they ran some tests and didn't find any evidence one way or another.
And this, ladies and gentleman, is how we know it was an EM-Drive test! Seriously, every actual EM-Drive test ever.


And they for some strange reason never manage to come up with a measurement setup that makes a serious attempt to rule out forces from air currents, magnetic fields, outgassing, etc.

Apply sensitive-enough measurement instruments to a sloppy experimental setup and you're going to measure something. They keep setting things up in ways that can only give inconclusive results, while working with equipment they clearly don't understand. For example, the Eagleworks tests had problems with nylon bolts melting inside the RF cavity during the test, and don't appear to have considered that this might release gases that could produce a thrust or even to be aware that they need to use a material that doesn't absorb the microwaves, and they burned out RF amplifiers by operating them at low pressures where they were subject to corona discharge. Every other experiment I've looked at was a similar display of incompetence on the part of the experimenters.

The whole thing has a lot of similarities with cold fusion, perpetual motion, etc. Look at E-Cat for a particularly good recent example.


Absalom wrote:
Though someone did supposedly come up with a theory that accurately describes the thrust, so maybe that'll go somewhere.


If you mean the "quantum vacuum thruster" stuff, it's just technobabble. "Quantum vacuum virtual plasma" is a mishmash of technical terms that sounds impressive.


Fri Jul 01, 2016 4:36 pm
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Post Re: The "Real Aerospace" Thread
Mjolnir wrote:
Absalom wrote:
Though someone did supposedly come up with a theory that accurately describes the thrust, so maybe that'll go somewhere.


If you mean the "quantum vacuum thruster" stuff, it's just technobabble. "Quantum vacuum virtual plasma" is a mishmash of technical terms that sounds impressive.
I don't recall. What I remember of it was that it was built around a principle of inertia (I think it was inertia) being a side-effect of the cumulative full-spectrum EM-flux experienced by an object. Specifically, something about the design was supposed to produce a differential, and thus produce a thrust if energy was provided. I don't see how this was supposed to produce better-than-photon-drive performance, but hey, I'm not a theoretic physicist, and I do know that "differential sails" are supposed to be desirable if they're even possible, so maybe there's something there.

As for Eagleworks, technically I believe that capacitor thing should be sort-of workable. I just doubt that you'd get measurable thrusts with the setup I've heard of (admittedly they're testing for photon displacement instead). In fact, I suspect that you'd need a very large and light configuration to get any measurable thrust: mass-dilation for available capacitor densities (or even battery densities!) strikes me as likely to be exceptionally minuscule. I wouldn't be surprised if the thrust of an ion-engine would require the capacitors to be replaced with some fairly light-weight blackholes.


Sun Jul 03, 2016 11:04 am
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Post Re: The "Real Aerospace" Thread
Absalom wrote:
As for Eagleworks, technically I believe that capacitor thing should be sort-of workable. I just doubt that you'd get measurable thrusts with the setup I've heard of (admittedly they're testing for photon displacement instead). In fact, I suspect that you'd need a very large and light configuration to get any measurable thrust: mass-dilation for available capacitor densities (or even battery densities!) strikes me as likely to be exceptionally minuscule. I wouldn't be surprised if the thrust of an ion-engine would require the capacitors to be replaced with some fairly light-weight blackholes.


I haven't seen any reason to think a full analysis wouldn't show it's just another oscillating-mass "Dean drive" type contraption, with the changes in mass of the capacitors/inductors involved exactly countered by the effects of the electrical current flowing through them. At best you could produce a gravitational wave drive, which would be just like a photon drive, just far more complicated and very low power due to the difficulty of producing gravitational radiation.


Mon Jul 04, 2016 2:38 pm
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Post Re: The "Real Aerospace" Thread
Mjolnir wrote:
Absalom wrote:
As for Eagleworks, technically I believe that capacitor thing should be sort-of workable. I just doubt that you'd get measurable thrusts with the setup I've heard of (admittedly they're testing for photon displacement instead). In fact, I suspect that you'd need a very large and light configuration to get any measurable thrust: mass-dilation for available capacitor densities (or even battery densities!) strikes me as likely to be exceptionally minuscule. I wouldn't be surprised if the thrust of an ion-engine would require the capacitors to be replaced with some fairly light-weight blackholes.


I haven't seen any reason to think a full analysis wouldn't show it's just another oscillating-mass "Dean drive" type contraption, with the changes in mass of the capacitors/inductors involved exactly countered by the effects of the electrical current flowing through them. At best you could produce a gravitational wave drive, which would be just like a photon drive, just far more complicated and very low power due to the difficulty of producing gravitational radiation.
Agreed.


Mon Jul 04, 2016 7:57 pm
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Post Re: The "Real Aerospace" Thread
Arioch wrote:
The Juno probe performs its orbital insertion maneuver on July 4.




The burn is scheduled for Under three minutes, guys. Granted, we won't know much about it for a while longer.


Mon Jul 04, 2016 8:16 pm
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Post Re: The "Real Aerospace" Thread
SpaceX is getting a bit more aggressive with their first stage recovery maneuvers, with less waiting around in case something's gone wrong. With their latest launch, the first stage pitched back and did the boostback burn just seconds after separation, while still inside the second stage's exhaust plume. The interaction of their exhausts, two 3 km/s streams of rarefied gases colliding head on, produced this sight:
https://scontent-vie1-1.xx.fbcdn.net/t3 ... 7982_o.jpg


Sat Jul 23, 2016 4:00 pm
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Post Re: The "Real Aerospace" Thread
Mjolnir wrote:
SpaceX is getting a bit more aggressive with their first stage recovery maneuvers, with less waiting around in case something's gone wrong. With their latest launch, the first stage pitched back and did the boostback burn just seconds after separation, while still inside the second stage's exhaust plume. The interaction of their exhausts, two 3 km/s streams of rarefied gases colliding head on, produced this sight:
https://scontent-vie1-1.xx.fbcdn.net/t3 ... 7982_o.jpg

It also produced an interesting trail:
http://apod.nasa.gov/apod/ap160721.html

They could try this on this particular flight (I assume) because it was an ISS supply mission, which is in a very low orbit.

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