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#820
by
saliva_sweet
on 10 Apr, 2015 21:10
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Looks like they're testing some edge of the envelope scenarios there. A landing with such lateral velocity would probably only happen in very strong wind. Had this been a land landing the capsule would have toppled and gotten dragged as well IMO.
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#821
by
russianhalo117
on 10 Apr, 2015 21:18
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Looks like they're testing some edge of the envelope scenarios there. A landing with such lateral velocity would probably only happen in very strong wind. Had this been a land landing the capsule would have toppled and gotten dragged as well IMO.
These are testing abort and emergency scenarios. Landing on land is the intended goal.
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#822
by
Robotbeat
on 11 Apr, 2015 00:57
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Ah, shoot, I missed this one!
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#823
by
Rocket Science
on 11 Apr, 2015 01:20
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Stable 2...
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#824
by
arachnitect
on 11 Apr, 2015 01:38
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I do not think CST-100 is supposed to roll over after water landing, is it? Getting out of the capsule may be a bit difficult?
Sometimes capsules end up upside-down ("Stable 2" position). They right the capsule before recovering the crew.
Looks like they're testing some edge of the envelope scenarios there. A landing with such lateral velocity would probably only happen in very strong wind. Had this been a land landing the capsule would have toppled and gotten dragged as well IMO.
I'd guess that it's easier to flip the capsule in the water. If one side starts digging in before the lateral velocity has bled off, it's going to capsize. Out in the desert, the capsule will bounce and slide, which should help it stay upright.
I am curious though, were they expecting it to make it through this particular test without capsizing?
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#825
by
darkenfast
on 11 Apr, 2015 09:07
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I do not think CST-100 is supposed to roll over after water landing, is it? Getting out of the capsule may be a bit difficult?
The Apollo-shaped capsules (Apollo, Orion and CST-100), are stable in the water in two positions: upright and upside down. Which position the Apollo capsules ended up in depended on wind speed, wave size and timing of where in the wave cycle the capsule hit. Airbags deployed automatically and would right the capsule if needed. Capsules with steeper sides (such as Dragon and Soyuz), are only stable upright (as far as I know).
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#826
by
Mike Harris-Stone
on 11 Apr, 2015 16:34
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Just a bit of space trivia...
That gantry they are using to drop test Orion and CST-100 is at NASA Langley in VA.
It was originally called the "Lunar Landing Simulator" and was used to hang LM mockups in the air which the astronauts would pilot to a test landing. The ground under it at one point was made to look like the lunar surface. I grew up just a few miles from it and remember going to see it as a boy.
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#827
by
catdlr
on 14 Apr, 2015 18:55
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CST-100 Design Tested in Langley Wind Tunnel
Published on Apr 14, 2015
Boeing's CST-100 spacecraft design underwent wind tunnel testing at NASA's Langley Research Center in Hampton, Virginia, as the company continues to refine and evaluate the spacecraft, which is being prepared for upcoming flight tests and ultimately missions to carry astronauts to the International Space Station.
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#828
by
adrianwyard
on 15 Apr, 2015 16:51
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#829
by
Lars-J
on 15 Apr, 2015 17:14
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Good observation. That's very odd. Perhaps I could see them being some kind of passive drag stabilization (during abort), but would they be hidden behind a service module fairing during launch?
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#830
by
adrianwyard
on 15 Apr, 2015 17:52
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Good observation. That's very odd. Perhaps I could see them being some kind of passive drag stabilization (during abort), but would they be hidden behind a service module fairing during launch?
That was my first guess too (analogous to Soyuz grid fins), but I don't think they're in the right place: the center of mass for the system will be way aft of that during abort as the service-module is still attached.
My guess is it's something to do with scale-model effects: additional drag is needed to make it behave like the real thing at abort speeds/pressures.
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#831
by
GraniteHound92
on 15 Apr, 2015 18:57
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#832
by
simonbp
on 16 Apr, 2015 15:06
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My guess is it's something to do with scale-model effects: additional drag is needed to make it behave like the real thing at abort speeds/pressures.
No, that would rather defeat the point of a wind tunnel if you couldn't actually test the shape you are interested in. Wind tunnels handle scale-effects by matching the Reynolds and Mach numbers to the real thing.
I'm pretty sure your first guess is right, they are testing a Soyuz style deployable fins.
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#833
by
adrianwyard
on 16 Apr, 2015 15:25
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The 'grid' shown isn't deployable, though. Perhaps its effects in non-abort scenarios (i.e. its drag) are negligible?
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#834
by
DanielW
on 16 Apr, 2015 21:32
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My guess is it's something to do with scale-model effects: additional drag is needed to make it behave like the real thing at abort speeds/pressures.
No, that would rather defeat the point of a wind tunnel if you couldn't actually test the shape you are interested in. Wind tunnels handle scale-effects by matching the Reynolds and Mach numbers to the real thing.
I'm pretty sure your first guess is right, they are testing a Soyuz style deployable fins.
My first guess was that they could not get the reynolds number high enough for a particular test and are using the ring to modify the boundary layer. I have no idea why they would need that though.
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#835
by
Atomic Walrus
on 21 Apr, 2015 22:13
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My guess is it's something to do with scale-model effects: additional drag is needed to make it behave like the real thing at abort speeds/pressures.
No, that would rather defeat the point of a wind tunnel if you couldn't actually test the shape you are interested in. Wind tunnels handle scale-effects by matching the Reynolds and Mach numbers to the real thing.
I'm pretty sure your first guess is right, they are testing a Soyuz style deployable fins.
Matching Re and Ma is the usual first order approach for scaling. In practice, wind tunnel testing involves a wide array of techniques to achieve the correct fluid mechanical behaviours. A grid like that is usually used to induce a particular scale of turbulence in a flow. That suggests they can't achieve a sufficiently high Reynolds number in the tunnel, and had to trip the flow into the right range of turbulence. I did my graduate research using a wind tunnel - the gap between the theory they teach you regarding the Buckingham Pi theorem and the experimental reality is a bit like finding our there is no Santa Claus.
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#836
by
arachnitect
on 14 May, 2015 01:11
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Mildly interesting.
Boeing selects Augusta firm to build parts for spacecrafthttp://www.kansas.com/news/business/aviation/article20810853.htmlD-J Engineering is manufacturing eight different parts for the Crew Space Transportation-100 spacecraft that Boeing will provide to NASA as part of its Commercial Crew Program.
Ryan Hernandez, D-J’s vice president of engineering and technology, said parts that the privately held company is manufacturing for the spacecraft include the capsule door, the frame of the door and frangible joints – which allow stages of the rocket that propel the spacecraft to safely separate during flight.
Post #1000
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#837
by
arachnitect
on 18 May, 2015 13:39
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#838
by
gongora
on 18 May, 2015 14:58
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I did this rendering for the folks over at Something Awful, and thought I'd post it here since its not L2. CST-100 and an Extended Cygnus.
Nice rendering!
It does bring up a curious question, one I'm sure we've noted before. First, CST Cargo uses the IDA port, limiting the size of some supplies.
But more importantly is the reach of Canadarm 2 to get to the rear of the CST Cargo's service module-turned-unpressurized trunk from IDA 1. From the rendering, isn't that a longer reach that the arm can do? Or, would DEXTRE work for this?
In the CRS-2 RFP it said the pictured docking port had limited access for unpressurized cargo, but it could also dock at the other IDA port (zenith) which should be in reach.
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#839
by
Ronsmytheiii
on 20 May, 2015 23:08
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