totm nov 2023 SpaceX Discussion Thread

[Wjolcz]

51 minutes ago, DAL59 said:

Exactly.  Wouldn't that be a lot simpler than a parafoil boat catching scheme?

The fairing would need a parafoil and they would need a boat to recover it anyway, so what difference does it make if they try catching it?

11 hours ago, SaturnianBlue said:

SpaceX's Propulsion Chief Technology Officer, Tom Mueller is speaking at the ISDC tomorrow. Since I'll be there, it's possible I could ask questions on this thread's behalf.

Will BFR have legs or will the landing pad have some sort of catching device?

Edited May 24, 2018 by Wjolcz

[tater]

 

12 hours ago, SaturnianBlue said:

SpaceX's Propulsion Chief Technology Officer, Tom Mueller is speaking at the ISDC tomorrow. Since I'll be there, it's possible I could ask questions on this thread's behalf.

Someone will certainly ask about the status of full sized Raptor testing, which is what I am interested in from him, I suppose.

What technique will Raptor use for starts/restarts?

[sevenperforce]

2 hours ago, DAL59 said:

4 hours ago, sh1pman said:

Should just make the fairings waterproof. 

Exactly.  Wouldn't that be a lot simpler than a parafoil boat catching scheme?

Waterproofing would be easier said than done. It's probably a lot easier to waterproof a cellphone than it is to waterproof bespoke fairings.

1 hour ago, Wjolcz said:

Will BFR have legs or will the landing pad have some sort of catching device?

I thought Elon already said the latter.

12 hours ago, StrandedonEarth said:

Maybe confirm Merlin can still run non-densified propellants?

We know Merlin can still run non-densified propellants. Please don't ask this!

12 hours ago, SaturnianBlue said:

SpaceX's Propulsion Chief Technology Officer, Tom Mueller is speaking at the ISDC tomorrow. Since I'll be there, it's possible I could ask questions on this thread's behalf.

1. Now that Block 5 is flying, how soon do you expect we will see more than one reflight of a booster?
2. Is the upper-stage recovery plan intended for research or for actual reuse?
3. Has any development been done on the auxiliary systems for BFR, like the RCS thrusters?

[wumpus]

On 5/22/2018 at 4:30 PM, MinimumSky5 said:

I love how there are lights in the spacecraft, just so we can get beauty shots!

Anyone know if SpaceX has Bob Fitch as a consultant?

[NSEP]

23 minutes ago, sevenperforce said:

 

1. Has any development been done on the auxiliary systems for BFR, like the RCS thrusters?

I have seen an article about people referring the BFR's RCS thusters as 'SuperDracos'. There might be a slight chance that the BFR thrusters are based on the SuperDraco engine, although i doubt it. I don't exactly know wich article i read though.

[Rakaydos]

14 hours ago, SaturnianBlue said:

SpaceX's Propulsion Chief Technology Officer, Tom Mueller is speaking at the ISDC tomorrow. Since I'll be there, it's possible I could ask questions on this thread's behalf.

It's been said that you joined SpaceX because you were getting bored. With the worlds first production Full flow stage combustion nearing completion... What's next for you? What comes after Raptor?

[tater]

 

[CatastrophicFailure]

2 hours ago, sevenperforce said:

Now that Block 5 is flying, how soon do you expect we will see more than one reflight of a booster?

IIRC he mentioned this around the time the first B5 launched, would most likely be some time next year I think.

 

[Barzon]

15 hours ago, SaturnianBlue said:

SpaceX's Propulsion Chief Technology Officer, Tom Mueller is speaking at the ISDC tomorrow. Since I'll be there, it's possible I could ask questions on this thread's behalf.

Can you ask if BFR will have a centrifuge? (because surely if you are going to Mars you will need a centrifuge or something)

[sh1pman]

8 minutes ago, Barzon Kerman said:

Can you ask if BFR will have a centrifuge? (because surely if you are going to Mars you will need a centrifuge or something)

Even BFR isn't big enough to house a hab ring. 

[Barzon]

How big is BFR compared to the ISS modules? Diameter wise?

[Ultimate Steve]

11 minutes ago, Barzon Kerman said:

How big is BFR compared to the ISS modules? Diameter wise?

We know this - BFR is 9m, the smallest pressurized ISS component (Pirs) is 2.55m, and the largest (Leonardo) is 4.57m.

Image for scale:

[Barzon]

Thanks @Ultimate Steve. I was thinking about the planned ISS centrifuge module, and if something like that would be incorporated into the BFR.

[CatastrophicFailure]

1 minute ago, Barzon Kerman said:

Thanks @Ultimate Steve. I was thinking about the planned ISS centrifuge module, and if something like that would be incorporated into the BFR.

I think the eventual plan is to use a Mars transfer that cuts the flight down to only 3 months or so instead of 6. Even at 6, it's possible for travelers to still be functional once they arrive there, especially if they have support waiting.

[Barzon]

Ah, OK, I have been thinking about this for a while and this has certainly helped.  

[Damien_The_Unbeliever]

6 hours ago, DAL59 said:

Exactly.  Wouldn't that be a lot simpler than a parafoil boat catching scheme?

I think you vastly overestimate how easy it is to make something waterproof when it's a complex piece of equipment that also has to deal with re-entry issues. As with most things discussed here, your everyday experiences are unlikely to be directly relatable to the issues experienced by aerospace equipment. Say we could make the fairing waterproof by spraying a thick layer of plastic over it - but now the outside layer doesn't have the characteristics required whilst it's still acting as a fairing during powered ascent and we can no longer mate the two halves of the fairing in the manner in which they need to work.

Okay, so a thick layer of plastic won't work to make this thing waterproof. You have to come up with a design (as indicated above) that works *both* whilst in use during normal flight regime *and* works during re-entry *and* doesn't significantly degrade through all phases of use and means it's actually reusable. Do you have such a scheme in mind beyond believing that a lot of fairly smart people have ignored common everyday experiences?

Edited May 24, 2018 by Damien_The_Unbeliever

[Wjolcz]

4 hours ago, sevenperforce said:

I thought Elon already said the latter.

But I thought it's only for the booster? When I said BFR I meant the ship.

[CatastrophicFailure]

 

wat. 

[Wjolcz]

3 hours ago, NSEP said:

I have seen an article about people referring the BFR's RCS thusters as 'SuperDracos'. There might be a slight chance that the BFR thrusters are based on the SuperDraco engine, although i doubt it. I don't exactly know wich article i read though.

I remember (though I might be wrong) Elon saying that the RCS nozzles would be scaled down Raptors. How would they restart them each time they need to adjust the approach or anything? I have no idea.

Edited May 24, 2018 by Wjolcz

[sh1pman]

14 minutes ago, Damien_The_Unbeliever said:

I think you vastly overestimate how easy it is to make something waterproof when it's a complex piece of equipment that also has to deal with re-entry issues. As with most things discussed here, your everyday experiences are unlikely to be directly relatable to the issues experienced by aerospace equipment. Say we could make the fairing waterproof by spraying a thick layer of plastic over it - but now the outside layer doesn't have the characteristics required whilst it's still acting as a fairing during powered ascent and we can no longer mate the two halves of the fairing in the manner in which they need to work.

Okay, so a thick layer of plastic won't work to make this thing waterproof. You have to come up with a design (as indicated above) that works *both* whilst in use during normal flight regime *and* works during re-entry *and* doesn't significantly degrade through all phases of use and means it's actually reusable. Do you have such a scheme in mind beyond believing that a lot of fairly smart people have ignored common everyday experiences?

Waterproof, reusable and space-capable. Impossible, for sure.

[Ultimate Steve]

2 minutes ago, sh1pman said:

Waterproof, reusable and space-capable. Impossible, for sure.

Waterproof, reusable, and space capable while originally being designed for only one? Difficult, but not impossible.

[Brotoro]

Does seawater damage the composite structure of the fairing? If a fairing gets dunked in the sea, can SpaceX strip off and reinstall all the other systems, and at least save the cost of building a new shell? 

[sevenperforce]

17 minutes ago, sh1pman said:

Waterproof, reusable and space-capable. Impossible, for sure.

As I understand it, the outer shell of the capsule has been replaced in all cases so far.

[NSEP]

2 minutes ago, Wjolcz said:

How would they restart them each time they need to adjust the approach or anythin? I have no idea.

The Raptor is ignited by sparks instead of hypergolic ignition fluids, wich means the Raptor doesn't have a very limited amount of ignitions. Using TEA/TEB makes no sense for a rocket intended to go colonize Mars. Its extremely difficult and expensive to make, (especially on Mars) and limits the amount of ignition.

https://forum.nasaspaceflight.com/index.php?topic=41363.700

 

[magnemoe]

1 hour ago, Brotoro said:

Does seawater damage the composite structure of the fairing? If a fairing gets dunked in the sea, can SpaceX strip off and reinstall all the other systems, and at least save the cost of building a new shell? 

Does not think so, water rarely damage composite, and at least the outside must handle some water as they are transported uncovered. 

Now the inside however must be able keep the clean room requirements for the satellite. 
This might be the hard part