totm nov 2023 SpaceX Discussion Thread

[Spaceception]

30 minutes ago, Clamp-o-Tron said:

Given that Super Heavy is taking a while (as expected) and Raptor production is (as far as we can tell) still to low to supply an orbital booster, I can see an anxious and impatient Elon deciding to just throw caution and patience to the wind and just give orbit a go.

Starship can't be reused if in SSTO mode. And this contract is something like a year away, while SpaceX seems to be specifically aiming for orbit by July. Which I think is a more reasonable prediction than this time last year when they vaguely predicted the end of 2020, while they were still dealing with cryo issues, Raptor was less developed, and only Starhopper had been flown. At this point, they're flying full scale prototypes every month or so, and finally have a couple boosters on the way.

Raptor production seems okay. If last summer's tweets about its development are any indicator, it looked like they were making 10 Raptors a month. This attempt to orbit is a bit more than 3 months away, and might slip out to fall anyway (either because of hardware issues, or general testing delays), so between that and their current stockpile (if needed), it should be enough.

Edited March 16, 2021 by Spaceception

[RCgothic]

Anyone got any clue what this might be?

 

 

 

TFR for Friday, possibly Static Fire Wednesday.

 

 

 

[RCgothic]

Photo from another angle prior to assembly.

 

 

Looks a little like a hydraulic thrust simulator?

Edited March 16, 2021 by RCgothic

[Elthy]

13 minutes ago, RCgothic said:

Anyone got any clue what this might be?

Maybe a rig to help with the construction of the launchpad. They still need some sort of ring on top of the six legs, dont they? It could be to cast concrete on there.

[kerbiloid]

1 hour ago, RCgothic said:

Anyone got any clue what this might be?

This.
To launch things.

Spoiler

First they were laughing, but now follow the wise advice.

 

[magnemoe]

1 hour ago, Spaceception said:

Starship can't be reused if in SSTO mode. And this contract is something like a year away, while SpaceX seems to be specifically aiming for orbit by July. Which I think is a more reasonable prediction than this time last year when they vaguely predicted the end of 2020, while they were still dealing with cryo issues, Raptor was less developed, and only Starhopper had been flown. At this point, they're flying full scale prototypes every month or so, and finally have a couple boosters on the way.

Raptor production seems okay. If last summer's tweets about its development are any indicator, it looked like they were making 10 Raptors a month, this attempt to orbit is a bit more than 3 months away, and might slip out to fall anyway (either because of hardware issues, or general testing delays), so between that and their current stockpile (if needed), it should be enough.

This, superheavy is not that hard, yes they need to get the engines not shaking each other apart and stuff like that but they probably overbuild the first versions. 
Landing it should be one of the easiest part, no flipping its basically and larger falcon 9 first stage. 
They figured out why they had problems with the engines. the flip stirred the header thanks dropping pressure and creating bobbles in the fuel. 
You can test this without an rocket, just flip and shake an header tank. as I understand the baffles helped creating bubbles. 

The real challenge is probably reentry. 

[zolotiyeruki]

12 minutes ago, kerbiloid said:

This.
To launch things.

  Hide contents

First they were laughing, but now follow the wise advice.

 

Or to catch them!

[RCgothic]

Launch Platform Phobos updates:

 

 

 

 

 

[RyanRising]

Official SpaceX SN10 recap video is up:

Plenty of new views, and we get to see more of that shot (yes!), but they didn't acknowledge it blowing up afterwards. I guess that wasn't part of the flight.

Edited March 17, 2021 by RyanRising

[tater]

 

[Brotoro]

If everything goes perfectly. Otherwise...later.

[CatastrophicFailure]

Death Star Elevator: confirmed. 

 

Imperial Guards meet you at the top... and show you to your table... 

[RealKerbal3x]

7 hours ago, RyanRising said:

but they didn't acknowledge it blowing up afterwards. I guess that wasn't part of the flight.

They did acknowledge it on their website:

"As if the flight test was not exciting enough, SN10 experienced a rapid unscheduled disassembly shortly after landing."

https://www.spacex.com/vehicles/starship/

[RyanRising]

1 hour ago, RealKerbal3x said:

They did acknowledge it on their website:

"As if the flight test was not exciting enough, SN10 experienced a rapid unscheduled disassembly shortly after landing."

https://www.spacex.com/vehicles/starship/

I know, I meant in the video I linked. Surely SpaceX has some up close & personal footage of that kaboom. I guess they’re saving it for the eventual “How not to Fly a Mars Rocket” (or your preferred title) montage that I really hope is going to show up eventually.

[kerbiloid]

                                                                                                                                                                                       (A post in Q&A thread reminded the old idea)

Phase A.

1.
Take Crew Dragon, make it uncrewed, remove/shrink the pressurized compartment, and increase fuel tanks instead. 
Call it Tug Dragon.

2.
Take the Dragon XL cargo compartment
Put it under the Tug Dragon capsule instead of trunk.
Attach a CBM berthing adaptor to its lower end.

3.
Launch this to ISS or LOP-G.
Self-dock with the Dragon IDSS port.

4.
With Canadarm take the XL Cargo Trunk, detach it from Tug Dragon.
Berth to a CBM port of the station.

5. 
Return the Tug Dragon to the Earth, prepare to the next flight.

6.
Unload goods from the berthed XL Cargo Trunk, fill it with bads, unberth and send it away with solid boosters.

***

Phase B.

1.
As the Tug Dragon and the XL Cargo Trunk always have same dimensions, put a Lyappa-style grappling fixture  on the XL Dragon Boxcar.

2.
Instead of manual detaching of the XL Dragon Boxcar with Canadarm, make a simplified big Lyappa matching the Tug/Trunk size and the station CBM port position.
Unlike Lyappa, put it on the station, not on the vessel.

3.
When Tug Dragon has docked, unfold/extend the Big Lyappa, grab the grappling fixture on the XL Dragon Boxcar hull, detach from Tug Dragon and berth to the CBM without manual operations, robotically.

4.
Have a Spacelab-derived logistics module of the station with axial IDSS port, four radial CBM ports, and two BigLyappas to automatically reposition the brought XL Dragon Boxcars from the docked Tug Dragon to any of the CBM radial ports.

***

Phase C.

As all berthed Trunks and the station are connected with same 1.25-wide CBM-compatible hatches, make the automatic logistics system.

1.
Put a coaxial wheel between the radial ports.
Put radially an extendable railway truss on it (like the one they actually use to move cargos through these hatches).
Put a grappling carriage on the rails.

2.
When the XL Dragon Boxcar is berthed, rotate the wheel towards this hatch.
Radially extend the railway truss attached to the wheel, to let it get through the hatch into the XL Dragon Boxcar.

3.
Automatically position the grappling carriage on the rails, take a cargo container from required place in the rack, bring it into the station module.
Automatically grab it with another carriage on the fixed axial railway and move this way to another part of the station, to automatically put it in the rack.

4.
Retract the extendable railway.

So, there is an uncrewed Starship-derived dry workshop orbitatl station with automatical Tug Dragon supply ship.

 

***

Phase D.

Use the same Tug Dragon with any other payload.
Including the Crew Dragon (launch it overturned in this case).

[MKI]

11 hours ago, RyanRising said:

I know, I meant in the video I linked. Surely SpaceX has some up close & personal footage of that kaboom. I guess they’re saving it for the eventual “How not to Fly a Mars Rocket” (or your preferred title) montage that I really hope is going to show up eventually.

If I had to guess when such a montage appears, it probably will be after the full stack of Starship was tested successfully. As I imagine they will have A LOT more content by then 

[tater]

Another NASA image of Dragon XL

[Guest]

wow that looks really cool

Previous rendering for reference

[RCgothic]

The bridge crane for the high bay has finally arrived!

 

Edit: huh, YouTube link is dead. Thumbnail still works though.

 

Edited March 18, 2021 by RCgothic

[RyanRising]

1 hour ago, RCgothic said:

The bridge crane for the high bay has finally arrived!

 

Edit: huh, YouTube link is dead. Thumbnail still works though.

 

I think the story with that is they forgot to include credits the first time around, and reuploaded it to fix that.

[sevenperforce]

16 hours ago, tater said:

Spoiler

Another NASA image of Dragon XL

Interesting that it appears to have a Canadarm grapple target on the side for berthing but an LIDS/NDS-compliant docking port on the nose like Dragon 2.

Does anyone have any idea what the three white boxes on the outside are supposed to be? Is that radar or coms? And what is that half-ring of six black cylinder things? Presumably they are sensors of some kind, probably star trackers, but why would you need that many of them in that kind of cluster?

It looks like there are no aft thrusters so Dragon XL will have 12 Draco thrusters on its body plus the four inline thrusters around the docking port, just like Dragon 2. Dragon 1 had 18 thrusters.

@Barzon said upthread that Anatoly Zak puts Dragon XL at 13 tonnes. I'm assuming that's the full mass with payload injected by FH onto TLI, including props and payload. 

Getting from TLI to NRHO efficiently requires a 180 m/s burn during the lunar slingshot and a 251 m/s insertion burn at NRHO. Those four inline docking port thrusters generate a combined 1.6 kN which is...............not a lot. The burn at flyby will take 24 minutes and burn 782 kg of propellant. The insertion burn will take a whopping 31 minutes and burn 1,013 kg of propellant. That's already significantly more propellant than the 1,388 kg carried by Crew Dragon.

If we assume Dragon 2 needs another 350 m/s of dV or so for docking, orbital maneuvers, and disposal/deorbit,  then we are looking at another 1,160 kg of propellant. If it can deliver around 5.5 tonnes to the Lunar Gateway then that puts its dry mass at around 3.5 tonnes. Dragon 1 had a dry mass of 4.2 tonnes but that included the heat shield.

Given that the total amount of propellant Dragon XL needs is just slightly greater than double the propellant capacity of Dragon 2 (and my estimate of 350 m/s for disposal is probably generous), SpaceX may simply reuse the exact same propellant tanks as Dragon 2...just in pairs.

[tater]

18 minutes ago, sevenperforce said:

And what is that half-ring of six black cylinder things? Presumably they are sensors of some kind, probably star trackers, but why would you need that many of them in that kind of cluster?

I assume krypton thrusters like Starlink. If they are asymmetrical (white boxes unpressurized cargo?), then the 3 that are orthogonal could be to keep the (low) thrust through the CM. They have a moment arm off the centerline for the arc of thrusters turning it to starboard in that image, and the 3 firing to port might correct for that? Seems bizarre vs just centering the thrusters, though.

[Clamp-o-Tron]

Looking at the top left, could it be ion thrusters? Ballistic capture into lunar orbit and then long firings to move to NHRO and rendezvous?

[tater]

Clearly the solar side is opposite the berthing port. The berthing side has forward thrusters like Dragon.

There are also 2 more cylinders facing aft (one visible above, the other between the 2 other white boxes).

Or payload mounts?

TBH, if I were to design this thing for a KSP station, I would put docking ports on both sides of the pressurized part, and when done, I'd detach the propulsion part and dispose of it. Every delivery would then build more station.

Of course every unique section is a possible failure I suppose (poor seal, etc). There's also trash to consider.

Apparently the XL will include a toilet and crew space to add to habitable volume on Gateway.

[sevenperforce]

11 minutes ago, tater said:

I assume krypton thrusters like Starlink.

I don't think so -- krypton thrusters are much flatter and concentric:

Spoiler

 

These look more like star trackers, intended for navigation:

Spoiler

 

 I just can't imagine needing that many of them in that small of a space.

12 minutes ago, tater said:

Clearly the solar side is opposite the berthing port. The berthing side has forward thrusters like Dragon.

Is it a berthing port or a docking port? It looks pretty clear to me that it's a docking port.