Author Topic: What is the curve down the side of the Dragon capsule  (Read 8434 times)

Offline Micahgtb

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I've done searches but can't seem to find anything. But my question is can someone tell me the purpose of the curved stripe down the side of the capsule. It is obviously removed at some point in the flight but I can't think of a good enough guess. Any facts? Thanks!

Photo is attached.

Offline Robotbeat

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Re: What is the curve down the side of the Dragon capsule
« Reply #1 on: 01/08/2012 04:18 AM »
Parachute lines.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Micahgtb

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Oh my guesses were good enough, thanks!

Offline edfishel

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Re: What is the curve down the side of the Dragon capsule
« Reply #3 on: 01/08/2012 08:56 PM »
Check the Space X web site for videos of their Dragon flights recently and you will see the parachute lines snap out of that holding area on the side of the capsule. Nifty.

Offline apace

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Re: What is the curve down the side of the Dragon capsule
« Reply #4 on: 01/08/2012 08:59 PM »
Check the Space X web site for videos of their Dragon flights recently and you will see the parachute lines snap out of that holding area on the side of the capsule. Nifty.

It's really a clever design!

Offline HMXHMX

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Re: What is the curve down the side of the Dragon capsule
« Reply #5 on: 01/09/2012 01:42 AM »
Check the Space X web site for videos of their Dragon flights recently and you will see the parachute lines snap out of that holding area on the side of the capsule. Nifty.

It's really a clever design!

No more clever than the McDonnell-Douglas Gemini bridle arrangement.

Offline Comga

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Re: What is the curve down the side of the Dragon capsule
« Reply #6 on: 01/09/2012 01:52 AM »
No more clever than the McDonnell-Douglas Gemini bridle arrangement.

No more clever, but a very clever adaptation. This fascinating illustration has the parachute up front and the bidle in back.  Because of the docking adapter up front, Dragon has no room there for the parachutes or drogue chutes.  SpaceX mirrored the Gemini system to put the chutes where they had volume, in back, and reversed the bridal run to the anchors forward so that the capsule hangs appropriately. 

Possibly no more clever, and not new, but clever enough.  SpaceX may have started with a blank sheet, but not an empty bookshelf.

Offline HMXHMX

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Re: What is the curve down the side of the Dragon capsule
« Reply #7 on: 01/09/2012 03:56 AM »
No more clever than the McDonnell-Douglas Gemini bridle arrangement.

No more clever, but a very clever adaptation. This fascinating illustration has the parachute up front and the bidle in back.  Because of the docking adapter up front, Dragon has no room there for the parachutes or drogue chutes.  SpaceX mirrored the Gemini system to put the chutes where they had volume, in back, and reversed the bridal run to the anchors forward so that the capsule hangs appropriately. 

Possibly no more clever, and not new, but clever enough.  SpaceX may have started with a blank sheet, but not an empty bookshelf.

"We stand on the shoulders of giants..."

FYI, I also used the same technique for both the XV and CXV spacecraft concepts.  (In the attached XV phantom, the orange lines are the bridle tunnels.)

Offline JayP

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Re: What is the curve down the side of the Dragon capsule
« Reply #8 on: 01/09/2012 04:11 AM »
Cirrus aircraft does the same thing on their CAPS full airframe parachute system.

Offline john smith 19

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Re: What is the curve down the side of the Dragon capsule
« Reply #9 on: 01/09/2012 07:46 AM »
SpaceX may have started with a blank sheet, but not an empty bookshelf.

A brilliant line. Their taking the idea and reversing it also demonstrate they are students of history (which given the number of ideas that seem to be reinvented every few years is very sensible) but not *slaves* of history.
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Offline apace

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Re: What is the curve down the side of the Dragon capsule
« Reply #10 on: 01/09/2012 09:54 AM »
As most technical solutions out there, something is always based on something else ;-) but I like the general idea of this heavy integrated capsule to put as much as possible in the lower section of dragon. But if they integrate more and more there (LAS) I have my questions if they have enough space or if they need to enhance this section. Question will be, if they already had LAS an other elements in mind at the drawing phase of dragon or not. If you look at the early animations of dragon, you see the LAS as a standard tractor tower and not integrated.

Offline JayP

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Re: What is the curve down the side of the Dragon capsule
« Reply #11 on: 01/09/2012 03:03 PM »
As most technical solutions out there, something is always based on something else ;-) but I like the general idea of this heavy integrated capsule to put as much as possible in the lower section of dragon. But if they integrate more and more there (LAS) I have my questions if they have enough space or if they need to enhance this section. Question will be, if they already had LAS an other elements in mind at the drawing phase of dragon or not. If you look at the early animations of dragon, you see the LAS as a standard tractor tower and not integrated.

But you've got to remember that similar looking engineering solutions can have vastly different rationales. If you compare Dragon to Gemini for instance, they were solving completely different engineering problems. Gemini was to accommodate a horizontal (slightly nose up) landing attitude with an eye towards a future paraglider recovery system with a high forward velocity component. Dragon on the other hand was dealing with the fact that the fore-deck is almost completely taken up by the CBM leaving no place to mount the parachutes or mortars like Apollo did. Without radically changing the size or outer mold line of the vehicle, what they came up with is the most logical choice.

As far as your question about packaging the LAS in the aft compartment, that is really a question of packing density and mass distribution. Right now, there are a lot of spherical tanks and cylindrical components back there. Spherical tanks don’t really pack all that well, a sphere in a cube of the same size (the length of one edge of the cube equals the diameter of the sphere) takes up only 52% of the volume of the cube. The engineers will need to find a way of fitting the supper Draco’s in the space available or figure out a way to get more volume, but that is what they’re paid for.
« Last Edit: 01/09/2012 03:03 PM by JayP »

Offline simonbp

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No more clever than the McDonnell-Douglas Gemini bridle arrangement.

Of course, that was a hold-over from the original Gemini recovery system...

Offline HMXHMX

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Re: What is the curve down the side of the Dragon capsule
« Reply #13 on: 01/09/2012 09:08 PM »
No more clever than the McDonnell-Douglas Gemini bridle arrangement.

Of course, that was a hold-over from the original Gemini recovery system...

Correct.  But the vestigial bridle arrangement for Gemini's paraglider reorientation meant that under a round parachute the airbag method of landing shock mitigation required for Mercury could be eliminated.  Gemini would impact the water at its edge rather than flat on.  Apollo had to do the same thing to reduce impact loads, and as far as I know, so does Dragon.

Offline Robotbeat

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Re: What is the curve down the side of the Dragon capsule
« Reply #14 on: 01/09/2012 09:12 PM »
No more clever than the McDonnell-Douglas Gemini bridle arrangement.

Of course, that was a hold-over from the original Gemini recovery system...

Correct.  But the vestigial bridle arrangement for Gemini's paraglider reorientation meant that under a round parachute the airbag method of landing shock mitigation required for Mercury could be eliminated.  Gemini would impact the water at its edge rather than flat on.  Apollo had to do the same thing to reduce impact loads, and as far as I know, so does Dragon.
And I believe so does Orion?
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline HMXHMX

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Re: What is the curve down the side of the Dragon capsule
« Reply #15 on: 01/09/2012 11:31 PM »
No more clever than the McDonnell-Douglas Gemini bridle arrangement.

Of course, that was a hold-over from the original Gemini recovery system...

Correct.  But the vestigial bridle arrangement for Gemini's paraglider reorientation meant that under a round parachute the airbag method of landing shock mitigation required for Mercury could be eliminated.  Gemini would impact the water at its edge rather than flat on.  Apollo had to do the same thing to reduce impact loads, and as far as I know, so does Dragon.
And I believe so does Orion?

I'n not following Orion, but I believe so.  Meanwhile I believe CST-100 wants to land parallel with the ground, since it uses airbags.

Offline Jorge

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Re: What is the curve down the side of the Dragon capsule
« Reply #16 on: 01/10/2012 12:14 AM »
No more clever than the McDonnell-Douglas Gemini bridle arrangement.

Of course, that was a hold-over from the original Gemini recovery system...

Correct.  But the vestigial bridle arrangement for Gemini's paraglider reorientation meant that under a round parachute the airbag method of landing shock mitigation required for Mercury could be eliminated.  Gemini would impact the water at its edge rather than flat on.  Apollo had to do the same thing to reduce impact loads, and as far as I know, so does Dragon.
And I believe so does Orion?

I'n not following Orion, but I believe so.

You're right.
JRF

Offline simonbp

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So, weirdly enough, CST-100 with its airbags and flat rigging is the closest vehicle since to the Mercury landing technique...

Offline ppb

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Re: What is the curve down the side of the Dragon capsule
« Reply #18 on: 06/01/2012 05:41 AM »
I've been thinking about this parachute suspension design for a while.  Maybe this has been discussed on other threads, but while it's an elegant packaging solution, I believe it introduces a potential failure mode absent on fore-packaged parachute designs (Mercury, Apollo).  That "rip-tunnel" has to be thin enough to zip apart at the right time, but stout enough to hold together during ascent and entry.  The smallest damage to that area during those latter times would cause LOC ala Columbia.  Has this been discussed?
Quam celerrime ad astra

Offline AS-503

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Re: What is the curve down the side of the Dragon capsule
« Reply #19 on: 06/01/2012 06:07 AM »
Not necessarily.

What about the strength of the bridle itself regardless of the tunnel sheath?

Are you suggesting micro-meteoroid damage for the LOC scenario?

If so, the potential for many other potential system failures (other than chutes) applies (but this is true for any spacecraft).

Planes hit birds sometimes. There is still some dice rolling.

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