Dragon v2 Kremlinology from Helodriver's unveiling pics

[ThereIWas3]

Various fans listed:-
3x Cabin, with 2x operating, Average 7900 RPM (RPM numbers are from pic 353)
3x Booster, with 1x operating, Avg 20000 RPM
1x Waste, operating, Avg 10500 RPM
3x Suite, none operating
2x Cargo, both operating, Avg 8450 RPM

Those fan RPM numbers seem awfully high to me.  Do spacecraft fans typically spin that fast?
In "The Right Stuff" the sound level from all the fans in the Mercury capsule was described as
being quite high.

[Jim]

Common sense. Or do you really think that this is final flight control software UI, final seat design, and that the cabin walls won't be covered and the cabin filled with equipment?

Wall covering is not needed.

[Sean Lynch]

There's a 500 degree difference between sunlit and dark surfaces in space...8 Super Dracos may be a bit loud compared to the Harley with open pipes that just went by. There may be some external insulation, but I would guess there is something very special planned for interior insulation. Perhaps black velvet with paintings of Elvis in Space.
well this just posted as I was typing...

Common sense. Or do you really think that this is final flight control software UI, final seat design, and that the cabin walls won't be covered and the cabin filled with equipment?

Wall covering is not needed.

Too bad for Elvis.

[Bob Shaw]

I was intrigued by the lighting and the positioning of the (few) bits of pipework. No cabling was visible (eg around the windows with the blue lighting), and few pipes. This suggests to me that the interior we're seeing may not be the actual inside of the main pressure shell, but is instead an inner sleeve behind which utilities are run. So the final product might well be quite neat as compared to the usual mess we see in everything except the Boeing vehicle (and SpaceShip Two). Having multiple gas-tight layers makes a lot of sense to me.

[Bob Shaw]

Has anyone else noticed that Dragon 2's trunk isn't actually symmetrical, except in general form? In the video you can clearly see that the paintwork/surface differs between the sun-facing side and the dark-facing side, with solar panels and/or radiators only on dark/light sides. Presumably the craft is able to tolerate barbecue mode where required, and the varying insolation while docked to the ISS. (Yes, I *do* mean insolation!)

[Coastal Ron]

There are versions of the bulkhead mount portion of electrical connectors that are stainless steel and hermetically sealed for use in very harsh conditions - undersea systems for instance.  I used to work for one of the companies that made them back in the 80's, and some of the vehicles that our mil-spec connectors went into included cruise missiles and ballistic missiles.

Where the panel is mounted, maybe there isn't a lot of direct heat?

Keep in mind that a goal of Dragons is rerusability.  Not only must the link between trunk and capsule break cleanly it must also be able to be re made with a new trunk.

That rules out anything threaded but you do not necessarily have to rely on just the tight fit between pin and socket. The alignment pins could be grooved to take a cam follower which rotates down the pin and pulls capsule and trunk more tightly together.

There are different types of connection modes for these types of connectors, depending on their use.  One popular style uses bayonets on the side of the bulkhead mount and the mate has a ring with slots so you could do a quarter twist to engage and lock.  Threaded rings are an option too, and none of these are appropriate for this application since they are typically for racked equipment that is only removed for R&R.

Insertion force is also an issue depending on the type of o-ring used, and the style of electrical contacts.

But for this particular application we're talking about a mostly clean operating environment, with only water being a significant contaminant while on the pad and during takeoff (i.e. rain).  There are quick disconnect styles already in use for the rocket industry, so these might of the same design.

I would imagine the mating connector is made from pliable material (including some form of soft environmental seal) and the mating pins have a short connection depth so there is little resistance to what is likely to be a "ripping away" disconnect.

[Burninate]

Do we have any indications on how the *basic dimensions* of the Dragon v2 compare to the Dragon v1?

From this thread:


Does it conform to this early concept diagram?

[Herb Schaltegger]

Those fan RPM numbers seem awfully high to me.  Do spacecraft fans typically spin that fast?
In "The Right Stuff" the sound level from all the fans in the Mercury capsule was described as
being quite high.

Yes, small fans must spin fast to move a respectable volume of air. The fans in the ISS CDRA were spec'd as magnetic bearing fans and designed to spin at something like 20,000 RPM, IIRC. And yes, noise on spacecraft is a very big concern. The ISS isn't nearly as quiet as originally spec'd for the Space Station Freedom program; it was found almost impossible for designers to keep the average SPL low enough (they were aiming for <40 dbA to meet an "NC40" spec). The fans, pumps, clicking valves, etc. just made it too much - remember, all those acoustic waves can't just radiate off into infinity like they can on Earth ... instead, they eventually hit the pressure vessel, which then vibrates and reflects that energy back inside.

Anyway, this is just another reason that the pretty interior of DragonV2 will almost certainly be covered with storage compartments, survival kits for off-nominal landing, cloth bags for late-load cargo, and simple padding to avoid head bumps and bruised elbows, etc.

[Lars_J]

Do we have any indications on how the *basic dimensions* of the Dragon v2 compare to the Dragon v1?

From this thread:


Does it conform to this early concept diagram?

Yes, the interior volume and width of 3.1 m appears to be unchanged from that diagram. (which I made a while back based on the earlier mockup and SpaceX Dragon PDF)

[MP99]

Re quick disconnects of the umbilical section, this looks neat:-

http://www.souriau.com/range-presentation/mil-dtl-38999-series-platform/mil-dtl-38999-series-3-derived/8d9/

cheers, Martin

[Herb Schaltegger]

Re the QD issue ... I had quite a bit to do with the QD's used for fluid connections through the vestibules on the US/European/Japanese modules for SSF/ISS, as well as those used for the rack/standoff utility connections. As part of an ad hoc working group that got put together to hammer all this stuff out in the early 90's, we junior engineers became very intimately familiar with the specs and applications for this stuff. Some of my knowledge isn't relevant to the discussion (mostly because for our purposes, all the connectors had to be captive - no loose dust caps or fastener clips/pins to float around; had to be accessible for both gloved and ungloved crew members; and thus had to have certain minimum and maximum connection forces and torques). The specifics of a lot of that stuff isn't applicable to an automated utility disconnect panel.

That said, the mil specs cover all these things and then some ... There is very little new under the sun in spaceflight, at least in terms of basic stuff like a spacecraft interface panel. It's just a matter, literally, of going to through vendor catalogs and picking the right ones based on your needs - for data or power, it's number of pins and their order - plus cabling on either end; type/shape of housing; whether it's keyed or not; connection type and environmental sealing requirements, etc. For fluids it's diameter of the line; flow rates and specs for the fluid being carried; material compatibility for the fluid; and then the type/shape of the housing, orientation keying; and so forth. You can specify this stuff for just about ANYTHING if you just dig deeply enough into the catalogs of any number of aerospace suppliers, even highly toxic/corrosive nasties used in the nuclear industry. Nothing needed for spaceflight holds a candle to the crazy requirements of that industry.

Once you've settled on the number and kind of interfaces and spec'd out each one, you just arrange them as needed or wanted on your panel and build it up.

[Helodriver]

Just uploaded a few minutes of video which may help with some of the Kremlinology on the umbilical panel on the outside of the spacecraft among other things.

https://www.youtube.com/watch?v=nsnQyZCrjsM&feature=youtu.be

[docmordrid]

Looks like there be engines up those nostrils. So much for  the net trolls calling it a mockup.

[MP99]

Looks like there be engines up those nostrils. So much for  the net trolls calling it a mockup.

Hmm, my assumption was that it would be dark up there if engines were fitted. I assumed the light coming down through those ports meant SDs were not fitted?

cheers, Martin

[Lars_J]

Looks like there be engines up those nostrils. So much for  the net trolls calling it a mockup.

At the risk of being labeled a "net troll" , take a closer look. Or do you think flight engines have an internal light in the chamber? Something is mounted there, but real SD's - unlikely.

[Squid.erau]

Those fan RPM numbers seem awfully high to me.  Do spacecraft fans typically spin that fast?
In "The Right Stuff" the sound level from all the fans in the Mercury capsule was described as
being quite high.

Yes, small fans must spin fast to move a respectable volume of air. The fans in the ISS CDRA were spec'd as magnetic bearing fans and designed to spin at something like 20,000 RPM, IIRC. And yes, noise on spacecraft is a very big concern. The ISS isn't nearly as quiet as originally spec'd for the Space Station Freedom program; it was found almost impossible for designers to keep the average SPL low enough (they were aiming for <40 dbA to meet an "NC40" spec). The fans, pumps, clicking valves, etc. just made it too much - remember, all those acoustic waves can't just radiate off into infinity like they can on Earth ... instead, they eventually hit the pressure vessel, which then vibrates and reflects that energy back inside.

Anyway, this is just another reason that the pretty interior of DragonV2 will almost certainly be covered with storage compartments, survival kits for off-nominal landing, cloth bags for late-load cargo, and simple padding to avoid head bumps and bruised elbows, etc.

You memory is pretty good Herb, but you understated things.  CDRA fan right now is running at 115,000 rpm, and rack fans run  20,000 to 40,000.  Our various cabin and IMV fans run between ~3000 to ~8000 rpm.

Matt

[Helodriver]

Looks like there be engines up those nostrils. So much for  the net trolls calling it a mockup.

Hmm, my assumption was that it would be dark up there if engines were fitted. I assumed the light coming down through those ports meant SDs were not fitted?

cheers, Martin

Not light, reflection on silver metal from the illuminated white floor.

[docmordrid]

Looks like there be engines up those nostrils. So much for  the net trolls calling it a mockup.

At the risk of being labeled a "net troll" , take a closer look. Or do you think flight engines have an internal light in the chamber? Something is mounted there, but real SD's - unlikely.

Ask helodriver if his cam light was on. Could be the pintile reflecting it.

[Mongo62]

Since nobody else has done so, I would like to thank Helodriver for this new video. I loved seeing greater detail on this beautiful spacecraft!

Plus Helodriver stated on another thread that the light-colored circles are indeed reflections.

[Herb Schaltegger]

You memory is pretty good Herb, but you understated things.  CDRA fan right now is running at 115,000 rpm, and rack fans run  20,000 to 40,000.  Our various cabin and IMV fans run between ~3000 to ~8000 rpm.

Matt

Wowzer, I don't remember the CDRA running THAT fast but hey, it's been 21 years since I last worked on this stuff. 

Also, I was more concerned with interface hardware - stuff that goes between the CDRA, TCCS, TCM, MCA, OGA, the standoffs, vestibules, end cones ... all the "bits and pieces" that no one seemed too concerned about until they realized how much of it there was and how much it was gonna cost - and mass! - in the aggregate.

That said, I need to get hold of a flatbed scanner someday and post this thing to L2 ...