SpaceX Dragon 2 Updates and Discussion - Thread 3

[FutureSpaceTourist]

twitter.com/thesheetztweetz/status/1593699861295435776

SpaceX director of mission management Sarah Walker says the company "recently decided" to build another Crew Dragon spacecraft, which will round out its fleet of eight Dragon capsules in total.

5 Crew Dragon
3 Cargo Dragon

https://twitter.com/thesheetztweetz/status/1593700080682504198

Walker: The decision to build an additional Crew Dragon capsule was to "make sure we can support as many flights as our customers want to fly."

twitter.com/thesheetztweetz/status/1593700352796172288

Walker said this during a briefing for SpaceX's CRS-26 mission for NASA, which is the company's fifth Dragon mission of 2022.

https://twitter.com/thesheetztweetz/status/1593701406480875521

Walker: The 5th Crew Dragon that SpaceX is building "should be ready in the 2024 timeframe."

[FutureSpaceTourist]

https://twitter.com/thesheetztweetz/status/1593703691076468737

Walker: SpaceX is targeting to reuse each Dragon capsule for about 15 flights, with caveats between missions  such as swapping out "soft goods" and "a  couple of hardware items" such as parachutes.

[JayWee]

So that's 13-24 months to build a Crew Dragon. Didn't expect it takes that long.

[FutureSpaceTourist]

Crosspost with more detail on possibly going as high as 15 flights per Dragon:

Near the end it was said that SpaceX is hoping to get “the vast majority of the components” of the Crew Dragons up to “about 15 flights”.
The one stated example of reused elements that might NOT make it to 15 flights was the parachutes, and even that dependent on post-flight inspections.
With five capsules and 15 flights each thats a fleet service life of 75 flights.

Just to add to this, it was also said that currently both cargo and crew Dragons are certified with NASA for 5 flights, but SpaceX are looking to work with NASA to significantly increase that. No number was put on that target NASA increased certification, other than SpaceX is assuring components as high as 15.

[DanClemmensen]

The existing four Crew Dragons would provide twenty flights total before the extension, but they already have flown or committed to a total of nineteen. Even a modest extension would probably cover any reasonable projection of the CCP + commercial model we have seen so far. An extension to eight flights would add twelve new missions. A larger extension plus a new capsule seems to imply a new business opportunity of some sort. An extension to ten missions with a fleet of five gives a total of 50 missions, which is 31 new missions above the ones we know about. So what are these new missions?

As a separate issue, each Crew dragon mission is also an F9 mission, so SpaceX will end up committing to extending the life of F9, including its entire retrieval and refurbishment infrastructure.

IDLE SPECULATION WITH NO BASIS WHATSOEVER: maybe SpaceX intends to use Crew Dragon to take drew to and from Starships in orbit until they can finally crew-rate Starship for EDL? Polaris 3 would be the first one of these. This opens the way for Lunar landing missions using Crew Dragon and HLS with no SLS/Orion.

[gemmy0I]

The existing four Crew Dragons would provide twenty flights total before the extension, but they already have flown or committed to a total of nineteen. Even a modest extension would probably cover any reasonable projection of the CCP + commercial model we have seen so far. An extension to eight flights would add twelve new missions. A larger extension plus a new capsule seems to imply a new business opportunity of some sort. An extension to ten missions with a fleet of five gives a total of 50 missions, which is 31 new missions above the ones we know about. So what are these new missions?

As a separate issue, each Crew dragon mission is also an F9 mission, so SpaceX will end up committing to extending the life of F9, including its entire retrieval and refurbishment infrastructure.

IDLE SPECULATION WITH NO BASIS WHATSOEVER: maybe SpaceX intends to use Crew Dragon to take drew to and from Starships in orbit until they can finally crew-rate Starship for EDL? Polaris 3 would be the first one of these. This opens the way for Lunar landing missions using Crew Dragon and HLS with no SLS/Orion.

I'm starting to wonder if the motivation for building a fifth capsule is more about having a big enough fleet to support an increased mission cadence than it is about extending the fleet's total service life.

Right now, supporting the ISS program full-time requires only two Crew Dragons in rotation, since the U.S. is only responsible for transporting ~half of the station's crew. But that's not going to be the case for the future commercial stations that will be coming online this decade. Even just looking at the Axiom Segment that'll be added to the ISS, I wouldn't be surprised if Axiom starts maintaining its own full-time four-member expeditionary crew rotation, above and beyond the 7 crew of the legacy ISS, once they have enough modules to support that many crew. But at the very least, they'll be flying short-duration private missions a lot more often.

There certainly seems to be enough market demand to support as much, even just from national space programs; NASA itself has expressed strong interest in buying commercial seats from Axiom to fly agency astronauts on (for instance) month-long missions to the ISS, if only they had the docking ports to do so (which Axiom Segment will bring). Despite NASA's contractual requirements (which are only a minimum) specifying just two full-time agency astronauts per private station in the CLD program, the agency's astronaut corps is awfully big relative to the limited number of flight opportunities they have. Their crew could be much better utilized if they could get back to a shuttle-era cadence of flying multiple tens of people every year. And that's not even counting the interest from ESA, JAXA, and rising space programs like the UAE's and Saudi Arabia's (who have already been eagerly snapping up Axiom seats).

Thinking through the logistics of this paints a picture of why SpaceX would want to have five Crew Dragons in the fleet. Supporting two 4-member crews at ISS/Axiom Station full-time would, in and of itself, require a fleet of at least three Dragons: two at the station and a third during handovers. Four would be ideal to allow some "wiggle room" in handover and refurbishment scheduling. And this is just for ISS/Axiom, not even counting free-flier missions like Polaris and the several other independent commercial stations that are supposed to come online within the decade.

Five Dragons feels like it would comfortably handle the market as it is likely to develop in the medium term (~2025-27 timeframe). Beyond that, they could find themselves needing several more capsules if all the credibly envisioned commercial LEO space stations (Axiom, Orbital Reef, and Nanoracks/Lockheed's Starlab) come to fruition. So I think even with five capsules, they are still very much expecting Starship to take over in the second half of the decade.

[cohberg]

Dragon's nosecone locking ring support structure was updated between Crew-3 (November 21') and CRS-25 (July 22')
^{(I could not find good video of CRS-24, Axiom 1, and Crew 4).}

Endurance, C210, was updated between Crew 3 and 5 which denotes that older Dragons do get retrofitted with this change.

^{Video Links below:
Crew-3 - C210 Old style (November 2021)
CRS-25 - C208 New Style (July 2022)
Crew 5 - C210 New Style Retrofit (October 2022)}

edit: (responding to post #1707)

If you look at the latter two, there are four exposed bolt heads in a rectangular pattern on the curved surface. They match with four threaded *unused* bosses on the 'original' image 1. This indicates to me at least that the curved piece is a panel is mounted over the original structural design.

The area with the 4 empty bosses (crew-3) that is referenced is 2 "bulkheads" over on the left.
The area with the 4 exposed screws (crew-5) only has 2 bosses in the crew-3 design.
See the quick overlay video where i take the transparency of the crew 5 image from 0-100% + annotated image with some reference ports



So, still a redesign (though subtler).  I didn't notice the empty bosses on the original, good catch.

[AstroWare]

Dragon's nosecone locking ring support structure was updated between Crew-3 (November 21') and CRS-25 (July 22')
^{(I could not find good video of CRS-24, Axiom 1, and Crew 4).}

Endurance, C210, was updated between Crew 3 and 5 which denotes that older Dragons do get retrofitted with this change.

^{Video Links below:
Crew-3 - C210 Old style (November 2021)
CRS-25 - C208 New Style (July 2022)
Crew 5 - C210 New Style Retrofit (October 2022)}

I dont have any reason to doubt you, but are you sure it's not just a new cover? One that was omitted on your 11/2021 photo above?

If you look at the latter two, there are four exposed bolt heads in a rectangular pattern on the curved surface. They match with four threaded *unused* bosses on the 'original' image 1. This indicates to me at least that the curved piece is a panel is mounted over the original structural design.

[mn]

Interesting tidbit about getting crewed Dragon operations (specifically loading crew before fuelling the rocket) approved by NASA:

Sounds to me like Eric is doing research for his next book:

https://twitter.com/sciguyspace/status/1590389834979463168

It is becoming axiomatic that any new medium or heavy lift rocket that is proposed without some element of reuse is doomed to fail.

twitter.com/elonmusk/status/1590391902662455296

Finally

https://twitter.com/sciguyspace/status/1590394239170404352

This one is entirely on you. I've been researching load-and-go, and no one wanted that but SpaceX. NASA official: "We tortured SpaceX for more than three years before we finally approved load-and-go. Had it been up to NASA, we would not have had the reusability revolution."

Edit to add:

https://twitter.com/spaceabhi/status/1590408817954947073

Very true.  There were studies NASA had done two decades prior that said it wasn't do-able. So it was an uphill task.

How is one related to the other? Why would we not have had reusability if NASA hadn't approved load and go?

[matthewkantar]

I am guessing because load-n-go is needed for densified propellant? Reuse seems doable with out the extra performance though.

[su27k]

How is one related to the other? Why would we not have had reusability if NASA hadn't approved load and go?

I think the relation is indirect: The load and go example shows NASA is conservative and does not like new things, thus it's natural to conclude SpaceX's style of reusability using propulsive landing would not come from NASA since it's new.

[Coastal Ron]

I am guessing because load-n-go is needed for densified propellant? Reuse seems doable with out the extra performance though.

Sure, densified propellant was a reason, but I think it was also the situation that with expendable rockets no one really knew how safe they were until you put propellant in them and launched them.

With reusable rockets, after the first time the rocket has launched, there is a degree of risk that has been retired. And while new risk could have been added from the recovery process, SpaceX was able to demonstrate that very little new risk was being introduced in the recovery process, and that if anything a previously flown rocket should not have the same degree of launch risk that an expendable rocket would have.

So loading crew first, then propellant, knowing that the Launch Abort System (LAS) was active just in case, allowed SpaceX to speed up the launch process, reduce risk to crew and support staff (not inserting crew when the vehicle is full of explosive propellant), and show that previously flown vehicles could be inherently safer than an expendable rocket that has never flown.

My $0.02

[Jim]

In researching a theoretical "how to bring all 7 down with crew dragon and no additional launches", I found out that SpaceX is using commercially available Collins Sweep-On Full-face O₂ masks

What good would those be in a spacecraft on orbit?

[cohberg]

What good would those be in a spacecraft on orbit?

Fire / Smoke without significant depressurization

In the context of Sokol suits and a theoretical party bus dragon:

After learning more about the Sokol and its connectors, I think that they would forgo trying to manufacture a cable and instead just thread the Dragon's O₂ mask ^{(a Collins Sweep-On Fullface[1][2] mask)} through the Sokol's entry hole, then tie it off with the cable coming through. It provides both O2 and comms and still allows you to have a pressure suit.

[Asteroza]

For the current situation on ISS, would it be feasible and make any sense to send up 3 IVA suits and some sort of emergency seat+rack set on the next cargo dragon, such that the ISS astronauts can assemble/install the emergency seat set within the currently docked crew dragon for party bus mode?

That would accelerate a lifeboat timeline in the face of difficulty accelerating Soyuz and crew dragon prep, but obviously create a number of interesting new schedule issues. The relevant question being, can the original crew dragon design for 7 seats form a design basis for this, or is the current 4 seat arrangement too different and requires a very different layout for squeezing in three jumpseats and an attachment rack?

[DanClemmensen]

For the current situation on ISS, would it be feasible and make any sense to send up 3 IVA suits and some sort of emergency seat+rack set on the next cargo dragon, such that the ISS astronauts can assemble/install the emergency seat set within the currently docked crew dragon for party bus mode?

That would accelerate a lifeboat timeline in the face of difficulty accelerating Soyuz and crew dragon prep, but obviously create a number of interesting new schedule issues. The relevant question being, can the original crew dragon design for 7 seats form a design basis for this, or is the current 4 seat arrangement too different and requires a very different layout for squeezing in three jumpseats and an attachment rack?

I think it would be faster to just turn C206.4 into the party bus before it flies. It is scheduled to fly in February for CRS-6 Crew-6. I don't think anything else that could carry those supplies is available or scheduled to fly any sooner. But why?

[Asteroza]

For the current situation on ISS, would it be feasible and make any sense to send up 3 IVA suits and some sort of emergency seat+rack set on the next cargo dragon, such that the ISS astronauts can assemble/install the emergency seat set within the currently docked crew dragon for party bus mode?

That would accelerate a lifeboat timeline in the face of difficulty accelerating Soyuz and crew dragon prep, but obviously create a number of interesting new schedule issues. The relevant question being, can the original crew dragon design for 7 seats form a design basis for this, or is the current 4 seat arrangement too different and requires a very different layout for squeezing in three jumpseats and an attachment rack?

I think it would be faster to just turn C206.4 into the party bus before it flies. It is scheduled to fly in February for CRS-6. I don't think anything else that could carry those supplies is available or scheduled to fly any sooner. But why?

Wait, wasn't the next flight up cargo dragon, not crew dragon? If the next is crew, yes, it makes sense to do a direct mod in terms of expediency.

[DanClemmensen]

For the current situation on ISS, would it be feasible and make any sense to send up 3 IVA suits and some sort of emergency seat+rack set on the next cargo dragon, such that the ISS astronauts can assemble/install the emergency seat set within the currently docked crew dragon for party bus mode?

That would accelerate a lifeboat timeline in the face of difficulty accelerating Soyuz and crew dragon prep, but obviously create a number of interesting new schedule issues. The relevant question being, can the original crew dragon design for 7 seats form a design basis for this, or is the current 4 seat arrangement too different and requires a very different layout for squeezing in three jumpseats and an attachment rack?

I think it would be faster to just turn C206.4 into the party bus before it flies. It is scheduled to fly in February for CRS-6 Crew-7. I don't think anything else that could carry those supplies is available or scheduled to fly any sooner. But why?

Wait, wasn't the next flight up cargo dragon, not crew dragon? If the next is crew, yes, it makes sense to do a direct mod in terms of expediency.

The totally infallible Wikipedia (  ) claims that the next cargo Dragon (CRS-27)  will fly on 19 February, and the next Crew Dragon (Crew-6) will also fly on 19 February. Somehow I doubt it.   If they nee a party bus quickly, I speculate that converting a Crew Dragon on the ground will be the quickest way to do it.

[DanClemmensen]

1. A fifth Crew Dragon is being constructed as we speak. Not because it is needed to serve the CCP contract, but because SpaceX sees a booming private-spaceflight market coming.
2. Crew Dragon is already in the process of being certified for at least 10 flights each. Initial certification for 5 flights had nothing to do with the spacecraft's complexity, but everything with it landing in salt water. But the combined experience from Dragon 1 and Dragon 2 (both Crew and Cargo variants) has shown that flying Dragon 2 for more than 5 flights per vehicle (both cargo and crew variants) is not a problem.

Thanks. I believe you, but I have not seen this in the press. The most recent I've seen for the fifth capsule is:
    https://spacenews.com/spacex-to-launch-last-new-cargo-dragon-spacecraft/
The most recent I have seen for the five-flight limit is quite old:
    https://spaceflightnow.com/2019/08/02/spacex-to-begin-flights-under-new-cargo-resupply-contract-next-year/

[Zed_Noir]

1. A fifth Crew Dragon is being constructed as we speak. Not because it is needed to serve the CCP contract, but because SpaceX sees a booming private-spaceflight market coming.
2. Crew Dragon is already in the process of being certified for at least 10 flights each. Initial certification for 5 flights had nothing to do with the spacecraft's complexity, but everything with it landing in salt water. But the combined experience from Dragon 1 and Dragon 2 (both Crew and Cargo variants) has shown that flying Dragon 2 for more than 5 flights per vehicle (both cargo and crew variants) is not a problem.

Thanks. I believe you, but I have not seen this in the press. The most recent I've seen for the fifth capsule is:
    https://spacenews.com/spacex-to-launch-last-new-cargo-dragon-spacecraft/
The most recent I have seen for the five-flight limit is quite old:
    https://spaceflightnow.com/2019/08/02/spacex-to-begin-flights-under-new-cargo-resupply-contract-next-year/

You have comment on this before in the "Commercial Crew - Discussion" thread and got my reply.

<snip>
SpaceX may also be able to build out one more Crew Dragon, which extends the total missions to 25. If 5 missions is a hard limit, they will need this anyway to fly that last mission. They seem to have at least the skeleton of an additional Crew Dragon already available.
<snip>

FYI, SpaceX is building a fifth Crew Dragon capsule. Also that SpaceX plans to increase the number of missions for each capsule to about 10. From one of the Crew Dragon pre-launch press briefing by SpaceX's Sarah Walker.