Dragon 2 on display at Newseum in DC on Wed June 11, 2014

[meekGee]

Pure conjecture and speculation - for a radical design idea - the door can have a simple groove, and the hatchway can have a flexible seal with a "cinching" band that pushes that seal into the groove.

The thing that enables strange seal designs like this is that overall this is a very low-performance seal, in terms of pressure, temperature, motion, corosivity, allowed leak rates, longevity....  so many things that are non-starters in hard seal environments become possible here.

[douglas100]

Dragon 2 shows no sign of any kind of docking window. Dream Chaser seems to be the same.

Obviously external cameras next to the docking mechanism can give a view for final alignment and the vehicle is able to dock automatically anyway.  But a year or so back there was some discussion that a docking window was a NASA requirement for a manned VV. Was that ever the case? And if so, has it changed?

[ThereIWas3]

Dragon 2 shows no sign of any kind of docking window. Dream Chaser seems to be the same.

Obviously external cameras next to the docking mechanism can give a view for final alignment and the vehicle is able to dock automatically anyway.  But a year or so back there was some discussion that a docking window was a NASA requirement for a manned VV. Was that ever the case? And if so, has it changed?

Musk is pretty clear that the Dragon2 is fully automatic and will dock itself.  SpaceX had a LIDAR experiment on the shuttle years ago in the early days of developing the technology.   Some of those NASA requirements are from the Astronaut Office who awlays wanted to make sure that manned NASA vehicles were complicated to fly, NOT automated, and you had to be a graduate of Test Pilot school to be Commander, all to preserve the requirement that there be an Astronaut Office.  A holdover from the "No SPAM in a can" days.

Welcome to the return of SPAM.  Dragon2 is not an experimental vehicle; more like an elevator.  You get in, you ride to ISS, you get out.  This is all about making it inexpensive.

[douglas100]

...Some of those NASA requirements are from the Astronaut Office who always wanted to make sure that manned NASA vehicles were complicated to fly, NOT automated, and you had to be a graduate of Test Pilot school to be Commander, all to preserve the requirement that there be an Astronaut Office.  A holdover from the "No SPAM in a can" days....

Thank you for your reply. But my question was: are these requirements still in effect? Do you have any insight?

[eriblo]

After looking closely at excellent pictures taken by Alpha Control and Heliodriver I'll add a post to the rampant hatch speculation:

I think the hatch shown is at least the same design as the actual flight hardware, but not completely in flight ready configuration. The attachment points of the hinges (red) and the thickness of the hatch (hard to judge due to angle and curvature) suggest that the smooth metal inner portion of the hatch does not insert significantly into the machined metal portion of the frame (green). If this is the case then the current configuration is:

The 4 linked Teflon tipped latches (yellow) extend into the frame and engage the outermost rib, i.e. the pressure vessel skin (the handle rotates the bottom one directly or through a gear). These will hold the hatch closed (against loads outward). There are no seals visible on the inside of the hatch or on the frame and there are two deep grooves and a small ridge along the inner edge of the hatch (blue). The loads directed in and sideways are therefore

1) taken up by these contacting the frame or a raised portion thereof. I have not seen any clear pictures of the "outside" of the frame around the opening but it appears to be coated/painted (not bare metal) and not completely smooth. The other alternative is that

2) these loads are counteracted by the wider white outer panel of the hatch resting on the dark lips visible at the top and bottom of the opening and sealing against the rest of the outer shell with the seal around the edge. This seal looks good enough for handling the capsule and weather (and possibly reentry plasma?).

My guess would therefore be that the hatch will have two o-ring type seals added in the grooves and that a matching surface will be added to the frame around the opening (possibly with a third seal corresponding to the surface between the groves and the innermost ridge). The current latches are likely only meant to provide easy closing/opening for now and will be replaced by sturdier mechanisms. These could possibly use the 12 sets of 1 + 2 holes around the hatch (cyan). These don't currently appear to have a use, unless the outside parts of the hatch is mounted on screws/bolts through the pressure vessel (unlikely?).

If one looks really deep into the tea leaves one might even see the drill holes in the frame (arrows) as mounting points for the "bolt holes" for these latches


I apologize for the wall of text and anybody who has superior hatch related wisdom is of course free to shoot my speculation down at any time

[ThereIWas3]

...Some of those NASA requirements are from the Astronaut Office who always wanted to make sure that manned NASA vehicles were complicated to fly, NOT automated, and you had to be a graduate of Test Pilot school to be Commander, all to preserve the requirement that there be an Astronaut Office.  A holdover from the "No SPAM in a can" days....

Thank you for your reply. But my question was: are these requirements still in effect? Do you have any insight?

That I can't say.  Just that bureaucracies tend to perpetuate themselves.  The last data point I have is STS-121 when they finallly started flying with the data cable on board that would allow, after being manually installed, a shuttle to be landed entirely by remote control.  I don't know whether it was ever tested.

[meekGee]

After looking closely at excellent pictures taken by Alpha Control and Heliodriver I'll add a post to the rampant hatch speculation:

I think the hatch shown is at least the same design as the actual flight hardware, but not completely in flight ready configuration. The attachment points of the hinges (red) and the thickness of the hatch (hard to judge due to angle and curvature) suggest that the smooth metal inner portion of the hatch does not insert significantly into the machined metal portion of the frame (green). If this is the case then the current configuration is:

The 4 linked Teflon tipped latches (yellow) extend into the frame and engage the outermost rib, i.e. the pressure vessel skin (the handle rotates the bottom one directly or through a gear). These will hold the hatch closed (against loads outward). There are no seals visible on the inside of the hatch or on the frame and there are two deep grooves and a small ridge along the inner edge of the hatch (blue). The loads directed in and sideways are therefore

1) taken up by these contacting the frame or a raised portion thereof. I have not seen any clear pictures of the "outside" of the frame around the opening but it appears to be coated/painted (not bare metal) and not completely smooth. The other alternative is that

2) these loads are counteracted by the wider white outer panel of the hatch resting on the dark lips visible at the top and bottom of the opening and sealing against the rest of the outer shell with the seal around the edge. This seal looks good enough for handling the capsule and weather (and possibly reentry plasma?).

My guess would therefore be that the hatch will have two o-ring type seals added in the grooves and that a matching surface will be added to the frame around the opening (possibly with a third seal corresponding to the surface between the groves and the innermost ridge). The current latches are likely only meant to provide easy closing/opening for now and will be replaced by sturdier mechanisms. These could possibly use the 12 sets of 1 + 2 holes around the hatch (cyan). These don't currently appear to have a use, unless the outside parts of the hatch is mounted on screws/bolts through the pressure vessel (unlikely?).

If one looks really deep into the tea leaves one might even see the drill holes in the frame (arrows) as mounting points for the "bolt holes" for these latches


I apologize for the wall of text and anybody who has superior hatch related wisdom is of course free to shoot my speculation down at any time

So IIUC:

What you're highlighting is a simple face seal (double), where the arms mechanism lies outside the seal, between it and the outer face.  (so is in vacuum)

The four rotating dogs are spiraled, and so create the force to tighten the seal.

----

For whatever reason, I was looking for a concentric seal mechanism, not a face seal, but this is simple enough.

I still wonder if there isn't another seal outside of the actuating mechanism, maybe not to hold pressure, but to prevent hot plasma for getting into the volume where the actuating mechanism is.

(So two pressure seals on the inner side, and a high-temperature low-pressure seal on the outside)

---

Especially with a face seal, you're sensitive to any warping, and so maybe you're right about the final mechanism  having more latches.  Maybe the four rotating cams (as shown) to do the first compression (under equa-pressure) and then 12 more latch-only mechanisms to secure it.

[CuddlyRocket]

Dragon 2 shows no sign of any kind of docking window. Dream Chaser seems to be the same.

Obviously external cameras next to the docking mechanism can give a view for final alignment and the vehicle is able to dock automatically anyway.  But a year or so back there was some discussion that a docking window was a NASA requirement for a manned VV. Was that ever the case? And if so, has it changed?

We know that the top of the Dragon V2 hinges to expose the docking mechanism and may well expose a docking window at the same time. I don't recall any pictures taken internally of the docking hatch area; did anyone take any? They might well show such a window.

[douglas100]

Dragon 2 shows no sign of any kind of docking window. Dream Chaser seems to be the same.

Obviously external cameras next to the docking mechanism can give a view for final alignment and the vehicle is able to dock automatically anyway.  But a year or so back there was some discussion that a docking window was a NASA requirement for a manned VV. Was that ever the case? And if so, has it changed?

We know that the top of the Dragon V2 hinges to expose the docking mechanism and may well expose a docking window at the same time. I don't recall any pictures taken internally of the docking hatch area; did anyone take any? They might well show such a window.

The animation shows no sign of a window when the Dragon nosecone opens. There appear to be only small devices beside the docking mechanism which could be cameras, sensors or both. Also, the position of the seats and instrument panel in the cabin do not appear to be positioned to allow the commander a view through a forward (upward) window, if one existed.

[docmordrid]

Dragon 2 shows no sign of any kind of docking window. Dream Chaser seems to be the same.

Obviously external cameras next to the docking mechanism can give a view for final alignment and the vehicle is able to dock automatically anyway.  But a year or so back there was some discussion that a docking window was a NASA requirement for a manned VV. Was that ever the case? And if so, has it changed?

We know that the top of the Dragon V2 hinges to expose the docking mechanism and may well expose a docking window at the same time. I don't recall any pictures taken internally of the docking hatch area; did anyone take any? They might well show such a window.

Found these online. Boosted the gamma on one to bring out the hatch. Could those two boxes house (stereo?) cams?

Top image from americaspace.com,

http://www.americaspace.com/?p=61314

[douglas100]

Good pictures. These boxes could indeed hold cameras and sensors, but if I've got the orientation of the cabin right, they don't align with the features on the docking collar shown in the animation.

[oiorionsbelt]

The final hatch design, is Falcon Wing.

[yg1968]

Dragon 2 shows no sign of any kind of docking window. Dream Chaser seems to be the same.

Obviously external cameras next to the docking mechanism can give a view for final alignment and the vehicle is able to dock automatically anyway.  But a year or so back there was some discussion that a docking window was a NASA requirement for a manned VV. Was that ever the case? And if so, has it changed?

We know that the top of the Dragon V2 hinges to expose the docking mechanism and may well expose a docking window at the same time. I don't recall any pictures taken internally of the docking hatch area; did anyone take any? They might well show such a window.

The animation shows no sign of a window when the Dragon nosecone opens. There appear to be only small devices beside the docking mechanism which could be cameras, sensors or both. Also, the position of the seats and instrument panel in the cabin do not appear to be positioned to allow the commander a view through a forward (upward) window, if one existed.

Heliodriver said that there was a window in the middle of the hatch and they were showing a movie of the ISS through that window.

http://forum.nasaspaceflight.com/index.php?topic=34841.msg1207024#msg1207024

[Elmar Moelzer]

Yes, there is a tiny circular window in the center of the "hatch". I am a bit skeptical about the docking port being final though. It does not seem to have a way to open at all. It might be a placeholder.

[cuddihy]

Yes, look at the center of the docking hatch in the pictures Doc Mordrid posted above. you can see the lower half the center window (viewing port really) in the first pic and the whole thing in the second.

[douglas100]

Heliodriver said that there was a window in the middle of the hatch and they were showing a movie of the ISS through that window.

http://forum.nasaspaceflight.com/index.php?topic=34841.msg1207024#msg1207024

I never thought to look at the hatch. The reason was I seem to remember that the NASA requirements were that the docking window should not be in the hatch. Yeah, that's right, and the hatch window appears as a spot in the animation as well. But it's not clear if the hatch window would be much use for manual docking. I imagine cameras are perfectly good for that, if required.

[rpapo]

Could those two boxes house (stereo?) cams?

They are positioned correctly to be the mortars they are using to kick out the drogue chutes.  Check out the NASA test video from last fall for reference.

[moralec]

A short youtube video from the event

www.youtube.com/embed/19Y3eZa337o

[Kabloona]

Was that Rep. Dana Rohrabacher leading the cheer for SpaceX?

[Prober]

Was that Rep. Dana Rohrabacher leading the cheer for SpaceX?

yes, on RT America no less