Author Topic: SpaceX Dragon 2 Updates and Discussion - Thread 2  (Read 221040 times)

Offline docmordrid

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #40 on: 10/12/2016 04:58 AM »
In 1977 UK Formula One driver David Purley crashed at 173 kmh, stopping in 66 cm - 178g.
« Last Edit: 10/12/2016 05:01 AM by docmordrid »
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Offline Chris_Pi

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #41 on: 10/12/2016 09:14 PM »
Think you can remove "pretty much" - that's well over 300 g, aka pink jelly territory  :o

Didn't feel like double-checking it right then, And If I don't it always turns out I'm wrong about something.  ;D So "pretty much".

Offline whitelancer64

Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #42 on: 10/12/2016 10:15 PM »
The record seems to be 214 g in a racecar crash in 2003 by Kenny Br臘k, though worth noting: "He suffered multiple fractures, breaking his sternum, femur, shattering a vertebra in his spine and crushing his ankles. He spent 18 months recovering from his injuries."

That said, I think we would all agree that sustaining high g forces would rapidly be lethal.
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Offline renclod

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #43 on: 10/12/2016 10:29 PM »

Dragon, yes. I'm not too sure about the trunk surviving intact though. ...just a hollow cylinder sitting on its rim on top of the second stage...

I guess most zero-zero abort scenarios consider a 1st stage RUD, not so much an upper stage issue. A LAS is a 90% insurance policy anyway, so yeah... a 3/4 trunk will probably quickly induce wild gyrations

Online envy887

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #44 on: 10/12/2016 10:43 PM »

Dragon, yes. I'm not too sure about the trunk surviving intact though. ...just a hollow cylinder sitting on its rim on top of the second stage...

I guess most zero-zero abort scenarios consider a 1st stage RUD, not so much an upper stage issue. A LAS is a 90% insurance policy anyway, so yeah... a 3/4 trunk will probably quickly induce wild gyrations

The fairing survived the anomaly quite well, and the trunk is similarly strong. I don't see it being an issue in this case.

Offline renclod

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #45 on: 10/12/2016 11:08 PM »

The fairing survived the anomaly quite well, and the trunk is similarly strong. I don't see it being an issue in this case.

All right, per NASA standard when a LAS has to fire, it must save the day 9 out of 10. Strong trunk ? no dispute here.

Online gongora

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #46 on: 10/13/2016 10:05 PM »
Tweets from Jeff Foust: One Two Three Four Five

Quote
[Benji] Reed [SpaceX]: SpaceX has delivered 15,800 kg of cargo to ISS, returned 12,100 kg to date. 11 more missions remaining on CRS-1 contract.

Reed: we値l use Dragon 2 for our CRS-2 missions, with propulsive landing (vs. splashdown). #ISPCS2016

Reed: we値l re-fly our first Dragon capsule on the SpX-11 mission, so relatively soon. #ISPCS2016

Reed: reusing Dragon capsules will allow us to close down the Dragon 1 production line and focus on Dragon 2. #ISPCS2016

Reed: biggest issue for reusing Dragon was dealing with water intrusion. Worked hard to update capsule to avoid it. #ISPCS2016

« Last Edit: 10/13/2016 10:52 PM by gongora »

Offline RoboGoofers

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #47 on: 10/14/2016 03:11 PM »
What does 'water intrusion' entail? Is it water getting into the pressure vessel, or just water in cracks and crevices outside the pressure vessel?

Offline king1999

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #48 on: 10/14/2016 03:13 PM »
What does 'water intrusion' entail? Is it water getting into the pressure vessel, or just water in cracks and crevices outside the pressure vessel?

Outside the pressure vessel but into the instruments and components around the bottom.

Offline Herb Schaltegger

Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #49 on: 10/14/2016 07:53 PM »
What does 'water intrusion' entail? Is it water getting into the pressure vessel, or just water in cracks and crevices outside the pressure vessel?

Outside the pressure vessel but into the instruments and components around the bottom.

There was at least one CRS mission where water evidently entered the pressure vessel (probably through a cabin vent or pressure relief valve). That's the kind of thing they were most concerned with.

http://aviationweek.com/space/water-found-inside-dragon-after-splashdown
« Last Edit: 10/14/2016 07:54 PM by Herb Schaltegger »
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Offline guckyfan

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #50 on: 10/14/2016 09:09 PM »
What does 'water intrusion' entail? Is it water getting into the pressure vessel, or just water in cracks and crevices outside the pressure vessel?

Outside the pressure vessel but into the instruments and components around the bottom.

There was at least one CRS mission where water evidently entered the pressure vessel (probably through a cabin vent or pressure relief valve). That's the kind of thing they were most concerned with.

http://aviationweek.com/space/water-found-inside-dragon-after-splashdown

I think that was the easy part. Water getting into the pressure vessel is entirely unnecessary.

The problem was the "service section", the part below the pressure vessel. Someone on reddit who said he was an intern with SpaceX has worked on the problem. That section is not completely watertight and they installed something like a bilge pump that pumps water out and protects the interior.

Offline Aerospace Dilettante

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #51 on: 10/16/2016 01:03 AM »

[Benji] Reed [SpaceX]:

Reed: we値l use Dragon 2 for our CRS-2 missions, with propulsive landing (vs. splashdown). #ISPCS2016



Thought Musk or Shotwell had flat out said that they weren't going to make a cargo version of Dragon 2, though I applaud the decision as it will give them experience propulsively landing, perhaps enough to make NASA comfortable with the idea of allowing manned prop landings.

Offline docmordrid

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #52 on: 10/16/2016 02:17 AM »

[Benji] Reed [SpaceX]:

Reed: we値l use Dragon 2 for our CRS-2 missions, with propulsive landing (vs. splashdown). #ISPCS2016


Thought Musk or Shotwell had flat out said that they weren't going to make a cargo version of Dragon 2, though I applaud the decision as it will give them experience propulsively landing, perhaps enough to make NASA comfortable with the idea of allowing manned prop landings.

IIRC CRS2 was originally going to use Dragon 1 for most flights for the CBM and Dragon 2 for fast return propulsive landings. IF the landing tests went (or go) well perhaps that's now inoperative. Need info if the upper mount now comes in NDA and CBM flavors
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Offline yg1968

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #53 on: 10/16/2016 04:03 AM »
SpaceX gave NASA the option of Dragon1 or Dragon2 for CRS2. It's up to NASA to decide. It's possible that NASA prefers Dragon2.

Offline sdsds

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #54 on: 10/16/2016 05:56 AM »
Need info if the upper mount now comes in NDA and CBM flavors

Isn't it clear from an ISS operational perspective that all cargo flights need to be berthed at a CBM? Because the docking ports must be kept available for crew rotation vehicles?
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Offline guckyfan

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #55 on: 10/16/2016 06:30 AM »
Need info if the upper mount now comes in NDA and CBM flavors

Isn't it clear from an ISS operational perspective that all cargo flights need to be berthed at a CBM? Because the docking ports must be kept available for crew rotation vehicles?

There will be two ports and only 1 is strictly necessary for crew.

I think that both options with IDA and CBM are in the contract and NASA can call for the one they need for every flight. It would be usually IDA but if there is a bulky item that does not fit through IDA they can have a Dragon 1 with CBM too.

Offline Roy_H

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #56 on: 10/16/2016 02:38 PM »

[Benji] Reed [SpaceX]:

Reed: we値l use Dragon 2 for our CRS-2 missions, with propulsive landing (vs. splashdown). #ISPCS2016



Thought Musk or Shotwell had flat out said that they weren't going to make a cargo version of Dragon 2, though I applaud the decision as it will give them experience propulsively landing, perhaps enough to make NASA comfortable with the idea of allowing manned prop landings.

My memory is quite different. I thought it was clear all along that Dragon 2 would replace Dragon 1 for both human and cargo versions. i.e. there would be a Dragon 2 variant with the CBM berthing port.
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Offline yg1968

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #57 on: 10/16/2016 06:05 PM »
Cargo Dragon2 can only dock.

See below:

Kirk notes Dragon and Dragon 2 involved. "One berths, one docks"
« Last Edit: 10/16/2016 06:58 PM by yg1968 »

Offline yg1968

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #58 on: 10/16/2016 06:14 PM »

Online gongora

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 2
« Reply #59 on: 10/16/2016 07:01 PM »
The CRS-2 contracts are posted here:

http://www.nasa.gov/centers/johnson/news/contracts/index.html

All of the useful parts are redacted.

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