SpaceX Falcon 9/Dragon COTS Demo (C2+) GENERAL DISCUSSION

[sanman]

Tell me, what's that gash or deep groove in the side of Dragon?



Is that some sort of damage caused by re-entry?

[Chandonn]

Tell me, what's that gash or deep groove in the side of Dragon?



Is that some sort of damage caused by re-entry?

That's been asked a hundred times in the SpaceX threads.  That's where the lines go for the parachutes.


[EDIT: I'm attaching a shot of the COTS-1 Dragon (after recovery) for comparison]

[mr. mark]

The grooves in the spacecraft are where the parachutes deploy lines go. There appears to be slight damage to the upper portion of the spacecraft. I'm wondering if this was related to the deploy.

[sanman]

The grooves in the spacecraft are where the parachutes deploy lines go. There appears to be slight damage to the upper portion of the spacecraft. I'm wondering if this was related to the deploy.

Yeah, that's what made me suspicious. Because I certainly don't remember the top circular portion of the craft looking chewed on like that. That white circular ring near the top looks like someone took a bite out of it.

A real dragon perhaps? 

[Chandonn]

The grooves in the spacecraft are where the parachutes deploy lines go. There appears to be slight damage to the upper portion of the spacecraft. I'm wondering if this was related to the deploy.

If you look up to the right of the COTS 1 Dragon I pictured above, the top also seems to have a "nick" in it.  Not sure if that's normal or not.  Just looks like it's in the same, or similar, condition.


[EDIT: SOLVED in the LIVE thread: it covers the parachutes:
http://forum.nasaspaceflight.com/index.php?topic=29037.msg909309#msg909309 ]

[sanman]

But boy, the whole surface of the thing seems to be charred. I thought the heat shield at the bottom takes nearly all the punishment, but even the upper parts of the capsule seem quite singed. If that GNC door were to have stayed open, I'm thinking the capsule wouldn't have made it.

[baldusi]

The grooves in the spacecraft are where the parachutes deploy lines go. There appears to be slight damage to the upper portion of the spacecraft. I'm wondering if this was related to the deploy.

If you look at the picture without any zoom, you'll see that every side of the groove looks like a foam. In fact, the whole top part, that appears "damaged", looks like pure foam. Which wouldn't be that strange, if you think about it. None of it is structural, and the top hat covers it from aerodynamic stress. So it might well be pure thermal foam. At least, that's my theory.

[SiriusGrey]

They mention 16-18 ft/s which is 4.9-5.5 m/s. This is equivalent to a fall from 2.4-3.1 m.

Assuming for simplification that they sink ~0.5m into the water (guesstimate) at constant deceleration, that deceleration would be around 2.5g-3g.

I had a closer look at the drop test video and did some frame-by-frame measurements. Using the published dragon dimensions for scale i'd say the splashdown velocity in that test was ~4.4 m/s (15 ft/s) and the  deceleration on splashdown up to 2g, my best guess being 1.5 g (for 0.2 seconds). (This gives a "zero g" load of 2.5g - 3g, as specified).

From the video, the Dragon seems to benefit from entering the water at an angle. This helps with keeping the instantaneous acceleration low (no "belly flop").

[sanman]

Anybody know where I can catch today's post-mission press conference online?

[Lars_J]

Anybody know where I can catch today's post-mission press conference online?

http://www.space-multimedia.nl.eu.org/index.php?option=com_content&view=article&id=7628

But beware... audio quality is horrible to epic levels of incompetence from some journalists. (unable or unwilling to mute their background sounds)

[butters]

But boy, the whole surface of the thing seems to be charred. I thought the heat shield at the bottom takes nearly all the punishment, but even the upper parts of the capsule seem quite singed. If that GNC door were to have stayed open, I'm thinking the capsule wouldn't have made it.

My understanding: as the outer surface of ablative heatshield burns away, some of the charred material is collected by the airstream and deposited on the sidewalls.

[Lars_J]

But boy, the whole surface of the thing seems to be charred. I thought the heat shield at the bottom takes nearly all the punishment, but even the upper parts of the capsule seem quite singed. If that GNC door were to have stayed open, I'm thinking the capsule wouldn't have made it.

My understanding: as the outer surface of ablative heatshield burns away, some of the charred material is collected by the airstream and deposited on the sidewalls.

Yes, and I also get the impression that the side wall exterior material ablates some as well. If the capsule was reused, they whole exterior layer would likely have to be re-applied anyway.

As for the GNC door not closing leading to LOM - I'm not so sure. Note that this door (and the front hatch) are on the side that receives the least amount of heating - and would be mostly protected from the worst effects by the angle of the reentry. (see image below)

[Nomadd]

 
 Guess I better take all those 3 mbs ku band dishes back off my boats.

That is for downlink.  Pointing requirements for uplink quite different

I'm not talking about Directtv internet or something. My uplink speeds are the same. Just plain, very expensive, Seatel 4010s. The motors are actually tiny. It's having a perfectly balanced dish that's the key to sub 1/2 degree point. The money came from unnamed companies wanting good real time video from places they'd rather not be.

 If they were worried about the door staying open they could just have it spring loaded with a heat fusible link. Latching it would be a little more complicated.

[mheney]

Latest main page article lists splashdown at 8:42am Central.  Shouldn't that be Pacific?

[DirtyDigger]

Anyone hear if there was an attempt to recover the first stage of the Falcon 9, on this test?  And what happened to it?

[QuantumG]

Anyone hear if there was an attempt to recover the first stage of the Falcon 9, on this test?  And what happened to it?

There was not. It burns up in the upper atmosphere.

[yg1968]

Anyone hear if there was an attempt to recover the first stage of the Falcon 9, on this test?  And what happened to it?

Somebody asked that question at a previous press conference and they said that they were not going to try this anymore. Their efforts are now concentrated on landing the first stage propulsively.

[manboy]

Latest main page article lists splashdown at 8:42am Central.  Shouldn't that be Pacific?

Houston uses central time.

[punder]

SpaceX, please add a ReEntryCam!   

[QuantumG]

SpaceX, please add a ReEntryCam!   

Or show us the video of the one you already have onboard!