Author Topic: SpaceX Dragon Air Circulation System  (Read 8194 times)

Offline rdale

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SpaceX Dragon Air Circulation System
« on: 08/04/2011 02:37 AM »
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110014250_2011013540.pdf

The Dragon capsule is a reusable vehicle being developed by Space   
Exploration Technologies (SpaceX) that will provide commercial cargo transportation to the International Space Station (ISS). Dragon is designed to be a habitable module while it is berthed to ISS. As such, the Dragon Environmental Control System (ECS) consists of pressure control and pressure equalization, air sampling, fire detection, illumination, and an air circulation system. The air circulation system prevents pockets of stagnant air in Dragon that can be hazardous to the ISS crew. In addition, through the inter-module duct, the air circulation system provides fresh air from ISS into Dragon. To utilize the maximum volume of Dragon for cargo packaging, the Dragon ECS air circulation system is designed around cargo rack optimization. At the same time, the air circulation system is designed to meet the National Aeronautics Space Administration (NASA) inter-module and intra-module ventilation requirements and acoustic requirements. A flight like configuration of the Dragon capsule including the air circulation system was recently assembled for testing to assess the design for inter-module and intra-module ventilation and acoustics. The testing included the Dragon capsule, and flight configuration in the pressure section with cargo racks, lockers, all of the air circulation components, and acoustic treatment. The air circulation test was also used to verify the Computational Fluid Dynamics (CFD) model of the Dragon capsule. The CFD model included the same Dragon internal geometry that was assembled for the test. This paper will describe the Dragon air circulation system design which has been verified by testing the system and with CFD analysis.

Offline corrodedNut

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Re: SpaceX Dragon Air Circulation System
« Reply #1 on: 08/04/2011 03:19 AM »
This picture was taken over two years ago, but it looks pretty close:

Offline Lars_J

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Re: SpaceX Dragon Air Circulation System
« Reply #2 on: 08/04/2011 07:52 AM »
Part of the ducts can be seen in this more recent photo. (attached)

Offline SpacexULA

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Re: SpaceX Dragon Air Circulation System
« Reply #3 on: 08/04/2011 02:25 PM »
It boggles the mind all the things that must be accounted for in human factors.  Thank you rdale, that was fun reading.

I know this is a daft question, but why don't they fill the interior volume with the white bags you see all over the ISS?  Are the cabnets there to help with airflow, or is it because some of the delivered items are too fragile to be in a pile of bags?
« Last Edit: 08/04/2011 02:29 PM by SpacexULA »
No Bucks no Buck Rogers, but at least Flexible path gets you Twiki.

Offline Lars_J

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Re: SpaceX Dragon Air Circulation System
« Reply #4 on: 08/04/2011 04:24 PM »
I think the weight distribution is too critical in a smaller spacecraft to have loose bags in the capsule. Especially for reentry.

Offline Jim

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Re: SpaceX Dragon Air Circulation System
« Reply #5 on: 08/04/2011 04:50 PM »
It boggles the mind all the things that must be accounted for in human factors.  Thank you rdale, that was fun reading.

I know this is a daft question, but why don't they fill the interior volume with the white bags you see all over the ISS?  Are the cabnets there to help with airflow, or is it because some of the delivered items are too fragile to be in a pile of bags?

they will.  Those photo are of an empty capsule.  It will be stuffed with bags in supporting frames.  There will be no room for anyone to be in it like the photo.
« Last Edit: 08/04/2011 04:51 PM by Jim »

Offline joek

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Re: SpaceX Dragon Air Circulation System
« Reply #6 on: 08/04/2011 05:11 PM »
Nominally full load looks like...

edit: p.s. There was an SAA amendment to increase the usable volume last year, so the image may be dated.  (Don't have a link to the original presentation at the moment; will try to find one.)
« Last Edit: 08/04/2011 05:17 PM by joek »

Offline Pedantic Twit

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Re: SpaceX Dragon Air Circulation System
« Reply #7 on: 08/04/2011 05:26 PM »
(Don't have a link to the original presentation at the moment; will try to find one.)

It's from this presentation (Page 16) (video), which was part of this.

Online Robotbeat

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Re: SpaceX Dragon Air Circulation System
« Reply #8 on: 08/04/2011 05:40 PM »
Wow. Just packed. What does a full ISS rack look like next to that?
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Offline Lars_J

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Re: SpaceX Dragon Air Circulation System
« Reply #9 on: 08/04/2011 05:51 PM »
Wow. Just packed. What does a full ISS rack look like next to that?

In theory a standard ISS rack would fit inside a Dragon, basically taking up the entire central space where people are standing in the internal pictures.

But there doesn't seem to be any plan at the moment to use Dragon to take standard ISS racks to and from the station.

Offline Jim

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Re: SpaceX Dragon Air Circulation System
« Reply #10 on: 08/04/2011 05:57 PM »
Wow. Just packed. What does a full ISS rack look like next to that?

same, just different shape

Offline paycom

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Re: SpaceX Dragon Air Circulation System
« Reply #11 on: 08/06/2011 06:42 PM »
Wow. Just packed. What does a full ISS rack look like next to that?
But there doesn't seem to be any plan at the moment to use Dragon to take standard ISS racks to and from the station.
But Dragon would be the only vehicle that could return them. I'm wondering whether NASA plans to return the broken MELFI 2 and repair it?

Offline JayP

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Re: SpaceX Dragon Air Circulation System
« Reply #12 on: 08/08/2011 02:29 PM »
But Dragon would be the only vehicle that could return them. I'm wondering whether NASA plans to return the broken MELFI 2 and repair it?

Putting an ISPR in the center of the dragoon would require designing, analyzing and building a support structure for it. (remember, the rack has to mount by the four corners of the front face, the bottom isn't flat) They would also have to leave room for the crew to reach the bottom corners to secure it. That would mean leaving out most of the other storage in the drogoon to do this.

The ISPRs are replaceable. If they really want to recover MELFI 2, it would make more sense to build a new one and send it up on an HTV to swap it with the old one. That would also take up only one launch instead of two.
« Last Edit: 08/08/2011 02:30 PM by JayP »

Offline Jim

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Re: SpaceX Dragon Air Circulation System
« Reply #13 on: 08/08/2011 02:32 PM »
The MELFI 2 could be removed from the ISPR in the ISS and placed in a specialized frame in the Dragon.

Offline JayP

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Re: SpaceX Dragon Air Circulation System
« Reply #14 on: 08/08/2011 03:31 PM »
The MELFI 2 could be removed from the ISPR in the ISS and placed in a specialized frame in the Dragon.

True, But what would be the point of bringing it back besides doing an engineering evaluation of why it failed? Didn't they already determine that?
« Last Edit: 08/08/2011 03:33 PM by JayP »

Offline Jim

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Re: SpaceX Dragon Air Circulation System
« Reply #15 on: 08/08/2011 04:29 PM »
The MELFI 2 could be removed from the ISPR in the ISS and placed in a specialized frame in the Dragon.

True, But what would be the point of bringing it back besides doing an engineering evaluation of why it failed? Didn't they already determine that?

to repair and replace

Offline JayP

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Re: SpaceX Dragon Air Circulation System
« Reply #16 on: 08/08/2011 04:31 PM »
The MELFI 2 could be removed from the ISPR in the ISS and placed in a specialized frame in the Dragon.

True, But what would be the point of bringing it back besides doing an engineering evaluation of why it failed? Didn't they already determine that?

to repair and replace
But that was my point. It would probably be cheaper to just build a new one.

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