The "Real Aerospace" Thread

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Arioch
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Re: The "Real Aerospace" Thread

Post by Arioch »

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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Re: The "Real Aerospace" Thread

Post by GeoModder »

Looks like they have roughly a launch each month?
Image

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Re: The "Real Aerospace" Thread

Post by Mjolnir »

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.

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Re: The "Real Aerospace" Thread

Post by Absalom »

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.

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Re: The "Real Aerospace" Thread

Post by Mjolnir »

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.

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Re: The "Real Aerospace" Thread

Post by Arioch »

This isn't aerospace exactly, but it's some pretty amazing high-tech fabrication.



http://carbon3d.com/

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Re: The "Real Aerospace" Thread

Post by Absalom »

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.

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Re: The "Real Aerospace" Thread

Post by Mjolnir »

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.

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Re: The "Real Aerospace" Thread

Post by Arioch »

The Juno probe performs its orbital insertion maneuver on July 4.


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Re: The "Real Aerospace" Thread

Post by ShadowDragon8685 »

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.

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Re: The "Real Aerospace" Thread

Post by Suederwind »

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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Re: The "Real Aerospace" Thread

Post by icekatze »

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.

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Re: The "Real Aerospace" Thread

Post by Absalom »

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.

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Re: The "Real Aerospace" Thread

Post by Mjolnir »

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.

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Re: The "Real Aerospace" Thread

Post by Absalom »

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.

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Re: The "Real Aerospace" Thread

Post by Mjolnir »

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.

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Re: The "Real Aerospace" Thread

Post by Absalom »

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.

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Re: The "Real Aerospace" Thread

Post by ShadowDragon8685 »

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.

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Re: The "Real Aerospace" Thread

Post by Mjolnir »

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

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Re: The "Real Aerospace" Thread

Post by Arioch »

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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