Author Topic: SpaceX COTS Demo 1 Updates  (Read 408186 times)

Offline arnezami

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Re: SpaceX COTS Demo 1 Updates
« Reply #1460 on: 02/10/2011 06:25 AM »
Nice  :)

Thanks.

Offline Lars_J

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Re: SpaceX COTS Demo 1 Updates
« Reply #1461 on: 02/10/2011 06:32 AM »
Here is an image showing some fluid dynamic simulation for Dragon reentry. Note how it is angled such that one of its sidewalls (the more scorched one) is almost paralell to the air flow - at a 15.5 degree angle:

http://www.spacex.com/00Graphics/Images/Dec07%20Web%20Update/17.jpg

EDIT: Hmm - I never noticed it is this image until now - but note that the model has 4 extruded areas modeled, just like the most recent image of the crew Dragon.
« Last Edit: 02/10/2011 06:38 AM by Lars_J »

Offline Antares

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Re: SpaceX COTS Demo 1 Updates
« Reply #1462 on: 02/10/2011 04:41 PM »
Note on the second picture on 1456 that it looks like the SpaceX logo was strategically placed to be on the "rare" side rather than the well-done side.
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Offline yg1968

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Re: SpaceX COTS Demo 1 Updates
« Reply #1463 on: 02/10/2011 04:56 PM »
This video at 6:45 shows part of the Dragon landing:

« Last Edit: 02/10/2011 04:57 PM by yg1968 »

Online ugordan

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Re: SpaceX COTS Demo 1 Updates
« Reply #1464 on: 02/10/2011 05:06 PM »
This video at 6:45 shows part of the Dragon landing:

That's from the parachute drop test earlier.

Offline stockman

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Re: SpaceX COTS Demo 1 Updates
« Reply #1465 on: 02/10/2011 05:10 PM »
This video at 6:45 shows part of the Dragon landing:

I don't think that is the actual landing from COTS 1 - I think they spliced together highights from COTS 1 and the Dragon Drop test done a few months previously... The splashdown capsule looked a little too clean to be the one that actually flew...

Nice video video overall however.. thanks
« Last Edit: 02/10/2011 05:11 PM by stockman »
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Online corrodedNut

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Re: SpaceX COTS Demo 1 Updates
« Reply #1466 on: 02/10/2011 05:16 PM »
With every passing day it seems more and more likely that there is simply no video of the splashdown, which I find disappointing. I also expected there would be video through-the-window during reentry, and perhaps a camera on the CBM hatch for an upward angle view of parachute deployment.

Oh well, maybe next time.
« Last Edit: 02/10/2011 05:16 PM by corrodedNut »

Offline yg1968

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Re: SpaceX COTS Demo 1 Updates
« Reply #1467 on: 02/10/2011 05:33 PM »
This video at 6:45 shows part of the Dragon landing:

That's from the parachute drop test earlier.

I stand corrected. They made it seem like it was from the splashdown since it was shown right after liftoff of Falcon 9. Their little video trick worked on me...
« Last Edit: 02/10/2011 05:37 PM by yg1968 »

Online Comga

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Re: SpaceX COTS Demo 1 Updates
« Reply #1468 on: 02/11/2011 04:45 AM »
It just occurred to me that the charred side of Dragon is where the parachute lines run.

That means that is is the "down" side when reentering, but the "up" during the descent under the parachutes.  The drop test footage shows the capsule hanging about thirty degree off of level.

When flying a reentry with lift, would the orientation be felt by the passengers?

Would the direction of the acceleration force be different on launch and reentry?

Would they do reentry with their feet "down", but finish with their heads down?  Or the other way around?
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Online HMXHMX

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Re: SpaceX COTS Demo 1 Updates
« Reply #1469 on: 02/11/2011 05:52 AM »
It just occurred to me that the charred side of Dragon is where the parachute lines run.

That means that is is the "down" side when reentering, but the "up" during the descent under the parachutes.  The drop test footage shows the capsule hanging about thirty degree off of level.

When flying a reentry with lift, would the orientation be felt by the passengers?

Would the direction of the acceleration force be different on launch and reentry?

Would they do reentry with their feet "down", but finish with their heads down?  Or the other way around?

See attached.

Offline Proponent

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Re: SpaceX COTS Demo 1 Updates
« Reply #1470 on: 02/11/2011 06:03 AM »
What the passengers will feel is the acceleration:  "down" will be in the direction opposite the acceleration vector, which in turn is the vector sum of the lift and drag vectors in the diagram posted by HMXHMX.  If, for example, the capsule is flying at an angle of attack of 15 degrees and the resulting drag force is 5 degrees off of the direction of flight, then the passengers will sense that the capsule is tilted by 10 degrees.

Post-splashdown pictures of Dragon seem to show that the hatch was on the rare side of the capsule.  So, as one expect and as is consistent with, for example, Apollo, passengers would feel that their feet were "lower" than their heads during re-entry.

Which photo is it that shows the parachute lines on the crispy side?  I agree this would suggest that the capsule splashes down with the passengers' heads lower than their feet, but this seems odd.  It's also at odds with Gemini and Apollo practice:  see this photo, for example. 
« Last Edit: 02/11/2011 06:04 AM by Proponent »

Online Ben the Space Brit

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Re: SpaceX COTS Demo 1 Updates
« Reply #1471 on: 02/11/2011 07:21 AM »
It just occurred to me that the charred side of Dragon is where the parachute lines run.

That means that is is the "down" side when reentering, but the "up" during the descent under the parachutes.  The drop test footage shows the capsule hanging about thirty degree off of level.

Not up but 'backward'.  If you watch the COTS-D video, you can see that, due to the fact the parachutes are in the lower SIM ring, they come out of the 'back' of the capsule, actually the downward-aligned part, during the initial phase.  It isn't until the parachute lines come clear of the vehicle that the vertical axis aligns with the parachutes.

When flying a reentry with lift, would the orientation be felt by the passengers?

The main force felt on the crew and passengers would be along the vehicle's vertical axis towards Earth due to deceleration.  The 'head-up/heads-down' is an illusion.  Down is 'forwards' (the direction of flight) for the entire re-entry/recovery phase.

Would they do reentry with their feet "down", but finish with their heads down?  Or the other way around?

The heads-down posture is simply so that the crew can see the horizon in case of having to manually steer the vehicle.  As stated above 'down' (the direction of perceptible gravity-like acceleration) would be along the line of flight towards Earth throughout this phase.

Which photo is it that shows the parachute lines on the crispy side?  I agree this would suggest that the capsule splashes down with the passengers' heads lower than their feet, but this seems odd.  It's also at odds with Gemini and Apollo practice:  see this photo, for example. 

Actually, it's the other way around.

Think about it: The parachutes are attached on the burnt side (the side over the crew's heads).  So, that end will actually be slightly higher up as the line from the attachment point to the centre of gravity would tilt the capsule slightly towards the hatch or 'foot' side.
« Last Edit: 02/11/2011 07:25 AM by Ben the Space Brit »
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Offline JayP

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Re: SpaceX COTS Demo 1 Updates
« Reply #1472 on: 02/11/2011 02:24 PM »

Actually, it's the other way around.

Think about it: The parachutes are attached on the burnt side (the side over the crew's heads).  So, that end will actually be slightly higher up as the line from the attachment point to the centre of gravity would tilt the capsule slightly towards the hatch or 'foot' side.

What are you basing your assumption that the crew's heads are away from the hatch on? All of the images on SpaceX's website indicate that their heads will be aligned just to the left of the hatch (The hatch will be just to the right of streight overhead when seen from inside the vehicle).

Plus, feet towards the hatch would make escape on the pad much more difficult.
« Last Edit: 02/11/2011 02:25 PM by JayP »

Online Ben the Space Brit

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Re: SpaceX COTS Demo 1 Updates
« Reply #1473 on: 02/11/2011 03:21 PM »
What are you basing your assumption that the crew's heads are away from the hatch on? All of the images on SpaceX's website indicate that their heads will be aligned just to the left of the hatch (The hatch will be just to the right of streight overhead when seen from inside the vehicle).

Plus, feet towards the hatch would make escape on the pad much more difficult.

It doesn't really matter; The only thing that matters in terms of this discussion is that the primary force would always be downwards through the TPS (deceleration).
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Offline JayP

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Re: SpaceX COTS Demo 1 Updates
« Reply #1474 on: 02/11/2011 05:09 PM »
What are you basing your assumption that the crew's heads are away from the hatch on? All of the images on SpaceX's website indicate that their heads will be aligned just to the left of the hatch (The hatch will be just to the right of streight overhead when seen from inside the vehicle).

Plus, feet towards the hatch would make escape on the pad much more difficult.

It doesn't really matter; The only thing that matters in terms of this discussion is that the primary force would always be downwards through the TPS (deceleration).

A. The decleration force will be opposite of the drag force, which this discussion has established will be at some angle to the axis of the vehicle. The magnitude and radial direction of the force is the question. A large enough latteral component of that force would cause blood flow in that direction. After 6 mounths in freefall, red-out, with the possability of a hemorrhagic stroke, is nothing to take litely.

B. Your statement I quoted above was in reguards to the vehicles attitude while under the chutes, not during the high drag reentry phase. With the parachute bridle on that side, the  direction of the offset vector would reverse when the chutes open.

C. Your missing the point of my question. I was just curious what information you had seen which would indicate that the couches are oriented that way. I have seen nothig of the sort.
« Last Edit: 02/11/2011 05:09 PM by JayP »

Online Comga

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Re: SpaceX COTS Demo 1 Updates
« Reply #1475 on: 02/15/2011 05:23 AM »
C. Your missing the point of my question. I was just curious what information you had seen which would indicate that the couches are oriented that way. I have seen nothig of the sort.

The CAD drawing on the left from the SpaceX website shows the astronauts' heads towards the hatch.  (You can see the faint image of the hatch with its window.) Comparing to the photo on the right side this will put them feet down during reentry, but head down when the Dragon is descending under the parachutes.

Yuck.  I wonder why they chose this?  There appear constraints about keeping the hatch out of the parachute shroud lines, but is there no other choice?
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline JayP

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Re: SpaceX COTS Demo 1 Updates
« Reply #1476 on: 02/15/2011 02:41 PM »
C. Your missing the point of my question. I was just curious what information you had seen which would indicate that the couches are oriented that way. I have seen nothig of the sort.

The CAD drawing on the left from the SpaceX website shows the astronauts' heads towards the hatch.  (You can see the faint image of the hatch with its window.) Comparing to the photo on the right side this will put them feet down during reentry, but head down when the Dragon is descending under the parachutes.

Yuck.  I wonder why they chose this?  There appear constraints about keeping the hatch out of the parachute shroud lines, but is there no other choice?

Yeah, that is what I saw too. Of course, the CAD image shows a different Draco arangement than was flown and it shows a standard, passive CBM, which would indicate a mode II docking (SSRMS grapple and berth with no back-up option) so it is a little suspect to begin with. I was wondering if there was any other info out there.

Offline yg1968

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Re: SpaceX COTS Demo 1 Updates
« Reply #1477 on: 02/15/2011 04:46 PM »
An update on the combination of COTS-2 and 3.
http://www.spaceflightnow.com/falcon9/003/110213cots2/
« Last Edit: 02/15/2011 04:46 PM by yg1968 »

Online Comga

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Re: SpaceX COTS Demo 1 Updates
« Reply #1478 on: 02/16/2011 03:27 AM »
An update on the combination of COTS-2 and 3.
http://www.spaceflightnow.com/falcon9/003/110213cots2/

Little new here.

Flight still nominally in July.  Hardware ready by June, including the berthing adapter.

One interesting, but not new, item is that the ISS crew for COTS-2 will be trained and prepared for the rendezvous mission, but the subsequent crew will be trained for the berthing COTS-3 mission.
« Last Edit: 02/16/2011 03:28 AM by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

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