SpaceX Dragon 2 Updates and Discussion - Thread 3

[yg1968]

A very clever enhancement of the experience. I don’t think there has ever been a transparent bubble like this for human Spaceflight before.

I wonder if this cupola will be made of transparent aluminum. Elon has spoken about using transparent aluminum for Starship but it would be cool if they used it for this crew Dragon.

[cuddihy]

Sorry if this has been asked already and if it's in the wrong section. Is Crew Dragon capable of delivering Astronauts to the Gateway space station as is, or would it need upgrades?

Upgrades to LAS to launch on FH and whole additional list which should be in a Lunar Dragon thread.

I still like the F9 launched Dragon with extra prop in the trunk, that docks to an FH launched S2 with a lot of residual Prop for the TLI burn. Probably cheaper than man rating a FH. And more performance.

That's quite a lot of extra prop...it's ~830 m/s to insert to NHRO from TLI. If I assume:
-storables are used to do both NHRO insertion and earth return
-830 m/s needed for NHRO insertion = 880 m/s needed for margin
Draco Isp of 300s to burn,

and work backwards from the NHRO -->
return to earth burn requirement w/ margin total- 430 m/s,  budget works out like this:

Dry Dragon crew at Earth Entry Interface: 12.1 t (weak assumption, the big storable tanks would increase this)
Dragon at NHRO gateway with Earth return prop: 14 t
Dragon at TLI with NHRO insertion 880 m/s: 18.9 t
So it takes a Dragon at LEO of ~19 t to be able to insert & return from NHRO.
Assuming the rest of the delta V comes from a FH upper stage which somehow required no additional mass for RPO with the Dragon
- so ~4 t dry & Isp of 311s, TLI ~3.26 km/s delta v.
-TLI burnout stack mass is 23 t
-LEO wet mass is 67 t. (19t DragoneXtended + 48t second stage)

-So you can indeed rough cut do this with 1 F9 crew + 1 FH with an extended trunk /storables.
-but the NHRO insertion deltaV needs to come up with the FH to keep Dragon crew weight below 16 tons. so a 14-15t Dragon Crew with ~54t FH + extended Dragon trunk + RPO support.

[Comga]

A very clever enhancement of the experience. I don’t think there has ever been a transparent bubble like this for human Spaceflight before.

I wonder if this cupola will be made of transparent aluminum. Elon has spoken about using transparent aluminum for Starship but it would be cool if they used it for this crew Dragon.

"Transparent Aluminum" is more a Star Trek quote than a material description.

Once confined to the world of Star Trek, transparent aluminum is now very much a reality, and can have significant real-world applications. 

Transparent aluminum, also known as aluminum oxynitride, is a transparent polycrystalline ceramic with a cubic spinel crystal structure made of nitrogen, oxygen and aluminum.

It is optically transparent in the near-ultraviolet, visible and infrared regions. It is four times harder than fused silica glass, 85% harder than sapphire and 15% harder than magnesium aluminate spinel. The material remains solid up to 1200°C (2190°F). It has good corrosion resistance and resistance to damage from radiation and oxidation. It is about three times harder than steel of the same thickness.

Domes, tubes, transparent windows, rods and plates can be produced from this material using conventional ceramic powder processing methods. Methods for manufacturing transparent aluminum remain refined. The cost of this material is similar to that of synthetic sapphire.

"four times harder than fused silica" and I have been immensely impressed by the toughness of fused silica.
One problem is that the ultraviolet transmission is high and broadband. 
It will need a UV blocker/absorber to prevent extreme sunburn.
But this looks really neat.

[abaddon]

Fascinating, and makes sense in that it isn't going to be docking anywhere.  Seems like a rather substantial modification and... I'm going to guess it is a one-way modification, i.e. this capsule will be reused for free-flying tourist flights and is not going to go back to the ISS.

Why would it be a one-way modification? Seems like an odd assumption to make.

Because I doubt it is a simple parts swap that would be easy to reverse, I doubt SpaceX and NASA want to certify the capsule for ISS transport after modification and restoration?  Because spacecraft aren't legos?  Lots of other possible reasons?

So, why would it not be a one-way modification?  Seems like an odd assumption to make.

[king1999]

Fascinating, and makes sense in that it isn't going to be docking anywhere.  Seems like a rather substantial modification and... I'm going to guess it is a one-way modification, i.e. this capsule will be reused for free-flying tourist flights and is not going to go back to the ISS.

Why would it be a one-way modification? Seems like an odd assumption to make.

Because I doubt it is a simple parts swap that would be easy to reverse, I doubt SpaceX and NASA want to certify the capsule for ISS transport after modification and restoration?  Because spacecraft aren't legos?  Lots of other possible reasons?

So, why would it not be a one-way modification?  Seems like an odd assumption to make.

It is not one-way.
"In terms of the engineering, the safety ... we've done all the engineering work," he added. "We will continue to go through all the analysis and testing and qualification to ensure everything is safe, and that it doesn't preclude any use of this spacecraft for other missions."

[Lars-J]

Fascinating, and makes sense in that it isn't going to be docking anywhere.  Seems like a rather substantial modification and... I'm going to guess it is a one-way modification, i.e. this capsule will be reused for free-flying tourist flights and is not going to go back to the ISS.

Why would it be a one-way modification? Seems like an odd assumption to make.

Because I doubt it is a simple parts swap that would be easy to reverse, I doubt SpaceX and NASA want to certify the capsule for ISS transport after modification and restoration?  Because spacecraft aren't legos?  Lots of other possible reasons?

So, why would it not be a one-way modification?  Seems like an odd assumption to make.

Because doing it that way would be ... not smart. Weklding it onto Dragon? What for? Do you think the docking adapter is permanently welded as well and and that it cannot be taken off to be replaced?

[DiskOperatingSystem]

Just a note, I think that they are going to modify the nosecone as well. Although it's just a render, if you zoom in on the picture released today, it seems like they are going for a ball-and-socket design to fit the glass cupola. I adjusted the lighting so you can see it better, but you can see that the black holes near the top and bottom show some curvature, as well as the entire ring structure. It's totally the perspective as we are viewing a circle from the side. I think that they have to have two nose cone variants, especially as the current one flattens out. I feel like the inside will also be padded to protect the glass on launch.

[jstrotha0975]

Why couldn't the cupola be a hatch that fits in the docking port and is removable like the hatches on an aircraft?

[Coastal Ron]

A very clever enhancement of the experience. I don’t think there has ever been a transparent bubble like this for human Spaceflight before.

I wonder if this cupola will be made of transparent aluminum.

Aluminum Oxynitride ceramic is the modern day personification of the reference to "transparent aluminum" in the 1986 Star Trek movie.

The company that makes this modern version is called Surmet, and they call their material ALON® Optical Ceramic. And yes, they do make panels that might be the right size for future Starship use, and it looks like they do make domes, but I think the size dome needed for the Dragon 2 would be something new for them - if they could make it.

However there are other materials that could be used, such as monolithic polycarbonate, which is used for the F-22 pilot canopy. And the advantage with polycarbonate is that it would be lighter weight - maybe half the weight of a glass or ceramic version.

[DiskOperatingSystem]

Just a note, I think that they are going to modify the nosecone as well. Although it's just a render, if you zoom in on the picture released today, it seems like they are going for a ball-and-socket design to fit the glass cupola. I adjusted the lighting so you can see it better, but you can see that the black holes near the top and bottom show some curvature, as well as the entire ring structure. It's totally the perspective as we are viewing a circle from the side. I think that they have to have two nose cone variants, especially as the current one flattens out. I feel like the inside will also be padded to protect the glass on launch.

Looking at the real Dragon, I'd like to correct myself from earlier and say that there seems to be plenty of room in the actual nosecone. A cupola/dome could perfectly fit in the Resilience as is. This has probably been a planned capability for a long time, but SpaceX had no reason to talk about it until now. 

[LastWyzard]

A very clever enhancement of the experience. I don’t think there has ever been a transparent bubble like this for human Spaceflight before.

I wonder if this cupola will be made of transparent aluminum. Elon has spoken about using transparent aluminum for Starship but it would be cool if they used it for this crew Dragon.

Aluminum Oxynitride is no more "transparent aluminum" than sapphire (an aluminum oxide).  It's a molecular compound and not a metal.  The property that makes aluminum a conductor, loosely bonded electrons, is the same property that makes it opaque.  The electrons absorb visible light, so no transparency.  As mentioned above there are plenty of options for a transparent dome.

[jarmumd]

Because doing it that way would be ... not smart. Weklding it onto Dragon? What for? Do you think the docking adapter is permanently welded as well and and that it cannot be taken off to be replaced?

The docking system is significantly integrated into the capsule.  It is not trivial to remove it.  Removing it also introduces significant documentation, as now you need to prove that something which was working properly, was removed and re-assembled and still functions properly.

It would make the most sense if the soft capture system stayed in place, and the dome mounted over it or around it somehow.

[Lars-J]

Because doing it that way would be ... not smart. Weklding it onto Dragon? What for? Do you think the docking adapter is permanently welded as well and and that it cannot be taken off to be replaced?

The docking system is significantly integrated into the capsule.  It is not trivial to remove it.  Removing it also introduces significant documentation, as now you need to prove that something which was working properly, was removed and re-assembled and still functions properly.

Of course it is not trivial to remove. But it can be removed. That is the point.

It would make the most sense if the soft capture system stayed in place, and the dome mounted over it or around it somehow.

Doubtful based on the image released. it would also limit visibility and room quite a bit. (see image)

[jarmumd]

Of course it is not trivial to remove. But it can be removed. That is the point.

Doubtful based on the image released. it would also limit visibility and room quite a bit. (see image)

I guess we will see if it's worth it for them to.

Your picture shows the soft capture ring deployed, I'm saying the dome could cover it when stowed.

[abaddon]

Of course it is not trivial to remove. But it can be removed. That is the point.

Your point is a little pointless.  Anything can be changed.  How hard it is to change and how much possible impact there is on certification are separate questions.  I'm open to the idea it can be done in a way that works for everyone involved, but I think it's reasonable to think it might not be that simple, either.

[su27k]

Of course it is not trivial to remove. But it can be removed. That is the point.

Your point is a little pointless.  Anything can be changed.  How hard it is to change and how much possible impact there is on certification are separate questions.  I'm open to the idea it can be done in a way that works for everyone involved, but I think it's reasonable to think it might not be that simple, either.

Note this is going to use the Crew-1 capsule which will return by the end of April, and Inspiration4 launch is in September, this doesn't give SpaceX much time to do the modification (on top of the refurbishment of Dragon itself), so the process can't be too complicated.

[cohberg]

An excellent video by Soichi on the D2 IVA suit.

Lots of great closeups and details in this video, some quick notes below.

There is a storage bag for the suits. When folded, they are surprisingly very compact.
We get better detail on the heel sliders.
We see the umbilical connector for the first time. Soichi provides new information about the various functions: a high pressure nitrox port (to provide pressure during depressurization), the conventional air circulation / cooling port, and the 14 pin data connector.
We see the integrated microphone in the helmet + color coded custom molded earpieces.
We see the zippers and the "white tooth" denoting when the zipper is closed. We also see how the astronauts enter from the bottom of the suit.
Suit is three layers. White outer layer is Teflon, the gray 2nd layer is Nomex, and then the inner layer that is airtight.



edit: Parallel discussion on reddit with a transcription of the video

00:00 Yes, Hello, everyone. I'm Soichi Noguchi, an astronaut.
00:13 This time, I'm sure there are many people who have been waiting for this time.
00:17 SpaceX spacesuit! I would like to introduce you.
00:21 Last November, when I came up here, well ... take it off ... and then 5 months ...! I haven't worn it for 5 months, but for the first time in 5 months ... I'd like to bring SpaceX spacesuit to the ISS side for the first time and introduce it from now on.
00:42 Actually, SpaceX's space suit looks like this. This is a bag that contains a suit, but it has my name on it. It's written in kanji. Thank you! Soichi Noguchi is written here ...
01:03 There are all the suits in this. After all, SpaceX suits have an integrated structure (ONE PIECE). I'm introducing you.
01:16 It's real! Genuine! Everyone!
01:22 I came out ... How is it? ... I can't help bragging about it.
01:39 Here it is. Integrated, gloves integrated (Integrated) Helmet integrated (Integrated). This is ... It is made of polycarbonate like a so-called motorcycle helmet. It is a nice shape that is said to have been designed using a 3D printer.
02:10 And the boots have an integrated structure like this. Clip it to the spacecraft seat with the heel slider. There is also a JAXA mark on the chest.
02:34 The only way to wear this is in the crotch. I will enter from here. It feels like you're wearing it from your head, and all communication with the spacecraft is connected here. When you remove the lid, there is a connector here.
03:07 So I went in from here, put my head out of here, and what to do with my hands. Actually, there is a zipper doorway here, and I can get my hands out from here.
03:18 So the gloves are supposed to be put on later.
03:25 The open areas of this spacesuit are the face, wrists, and crotch.
03:34 It is the innermost layer that prevents air from leaking. This is the zipper (closed with a red string) to close it. The outer layer is Teflon-coated to make it slippery when entering spacecraft seats. The inner layer (the gray part of the neck) uses fibers to increase strength. It has such a three-layer structure.
04:14 The innermost airtight layer is guaranteed to be airtight by closing the red zipper and closing to the white mark on the farthest edge.
04:45 We put on our spacesuits and do a Leak Check at the end, but the zippers make sure there are three places between each hand and crotch. Then close the helmet.
05:08 The back is flat, isn't it? This part is in close contact with the sheet, but the impact of water landing is applied here, so it is important how smooth this part is. It's very smooth.
05:35 This helmet, but one thing to say is that the earphones are attached to the earphones that you can put in your ears separately from the helmet. I'm on another. The microphone is on the inside, and the earphone and microphone are connected to the spacecraft via a connector.
06:08 Furthermore, things that cool the spacesuit also come in from here.
06:15 This is the air for circulation.
06:18 The small one on this side adds a little high pressure air in an emergency, but for that ... the name Nitrox? Comes in from here.
06:29 This side is for circulation. This side is for air supply (or intake?).
06:31 The metal chips here are supposed to be exchanged in various ways.
On the screen, it is written as "Cooling air / Emergency oxygen / Electrical connector".
06:45 How was it? So in the first half, I introduced the space suit itself. In the second half, I would like to introduce you to the place where you actually wear this space suit. See you again.

[FutureSpaceTourist]

Interesting update from Crew-2 on Dragon changes and positive impact on launch criteria:

Interesting explanation earlier of changes to Crew Dragon. 10% increase in abort engine performance has doubled the ground wind speeds that they can safely launch in. Also Dragon now has a go around capability of ISS that enables the exterior of the ISS to be surveyed / inspected / photographed. I think they said this is the only vehicle currently able to do that.

At post-launch news conference Steve Stich said that without the Dragon improvements made since Crew-1, for dealing with on-shore winds, they would not have launched today.

[FutureSpaceTourist]

https://twitter.com/tylerg1998/status/1386094755541667842

What’s interesting is, in that first photo, you can see a lot of #CrewDragon’s nosecone hardware in great detail!

Red - Draco forward thrusters
Blue - electrical and data connections to ISS
Yellow - star trackers for attitude control
Green - LIDAR sensors
Purple - docking camera

[jarmumd]

https://twitter.com/tylerg1998/status/1386094755541667842

What’s interesting is, in that first photo, you can see a lot of #CrewDragon’s nosecone hardware in great detail!

Red - Draco forward thrusters
Blue - electrical and data connections to ISS
Yellow - star trackers for attitude control
Green - LIDAR sensors
Purple - docking camera

Not sure that's the docking camera, it certainly not the camera the astronauts would use for docking, and I've never seen a video feed from it.  I suspect that's something else.