totm nov 2023 SpaceX Discussion Thread

[satnet]

30 minutes ago, DAL59 said:

Is this the same thing as Vapor Lock caused by lack of ullage?  

As I understand it no, though they are similar and likely to have similar (dire) consequences. Cavitation occurs is when voids form in a liquid due to forces acting on it. It generally occurs in the pumps themselves (though any condition that causes a rapid change in pressure can produce it) and doesn't require a pre-existing void. Vapor lock due to ullage occurs because the liquid is separated from the fuel system by voids in the tank. They both produce voids that interrupt the flow, but are produced by different phenomena.

Cavitation is particularly nasty since it generally occurs right next to moving parts and when these voids collapse they often produce shock waves powerful enough to damage parts. This can cause micro-pitting that eats away at blades and other parts of the pump. This is in addition to mass flow and combustion issues.

[Spaceception]

Just recently came out

 

 

[tater]

 

[Racescort666]

I suggested this up thread but I'm making the claim now: Aerial recovery. A Black Hawk has more than enough payload capacity to nab one of these out of the sky.

Now, if ULA would get their act together, we would have CONVERGENCE!!!

[Damien_The_Unbeliever]

Nope. I think they're still planning the "catchers mitt" net recovery. They're using a helicopter for the practice *drops*.

[tater]

It's odd unless they get the arms back on Mr. Steven, pronto (or they'll miss a recovery opportunity).

[DAL59]

(not mine)

[CatastrophicFailure]

5 hours ago, DAL59 said:

(not mine)

Reminds me of the end of Space Cowboys... 

[Toonu]

Hi guys, will BFR with two side Falcon 9s work as bigger Falcon heavy or is it more efficient to send the core than spend more fuel on side boosters? (I know...speculation...)

[MinimumSky5]

AFAIK, there is no plan to do a droneship recovery for the BFB, so it's likely a wasted exercise. It would also require the BFB to be modified to accept the lateral boosters and transmit the extra force to the BFS, and we saw with Falcon Heavy how difficult that is.

[Xd the great]

51 minutes ago, Toonu said:

Hi guys, will BFR with two side Falcon 9s work as bigger Falcon heavy or is it more efficient to send the core than spend more fuel on side boosters? (I know...speculation...)

If you mean a BFR with the booster boosted by falcon 9s, I say no. Falcon 9 would not increase the payload that much, but will instead add costs to refurbrishment and recovery.

If you mean a bfs (the ship) boosted by falcon 9 like how the space shuttle was boosted by solid rocket boister, I say no. Also. The cost of refurbrishment and fuel of a bfr booster is lower than that of 2 falcon 9s.

If you start thinking about a big falcon heavy, aka 3 boosters with a ship like th FH, no. The load on the centre core will rip it apart, and elon hates reuseable core for reasons such as higher reentry heat and aerodynamic forces.

Still, 93 rocket engines firing is so kerbal, Imma try it out tonight.

[ChrisSpace]

On 22 September 2018 at 7:44 AM, Spaceception said:

So, 2028... Does that mean the date for a crewed Mars landing has slipped 4 years? Because I imagine a base can be built in the first crewed mission. Gives them more time to test everything though, which is good. And a date I was honestly expecting.

He meant the level of development in that picture, with four BFRs on the surface at once and proper construction underway.

On 23 September 2018 at 3:48 AM, Mad Rocket Scientist said:

Great video simulating the lunar flyby trajectory:

Well that answers my other questions.

[tater]

6 hours ago, Toonu said:

Hi guys, will BFR with two side Falcon 9s work as bigger Falcon heavy or is it more efficient to send the core than spend more fuel on side boosters? (I know...speculation...)

That's never going to happen.

One, they're not going to have both propellant types on the same pad, it's needlessly complex.

Two, part of the point of BFR is orbital refilling operations. That is a capability that vastly multiplies what we can do in space.

[sh1pman]

36 minutes ago, tater said:

That's never going to happen.

One, they're not going to have both propellant types on the same pad, it's needlessly complex.

Two, part of the point of BFR is orbital refilling operations. That is a capability that vastly multiplies what we can do in space.

Also, pretty sure that 2 BFR launches will be way cheaper than one BFR-FH hybrid (+R&D, modified core, assembly, pad upgrades, etc). 

[DAL59]

What about a BFR superheavy?  With 7-3-1 asparagus staging?  slightly sarcastic

[CatastrophicFailure]

 

[Ultimate Steve]

"ispace"

Apple is invading the moon...

[tater]

3 minutes ago, DAL59 said:

What about a BFR superheavy?  With 7-3-1 asparagus staging?  slightly sarcastic

No.

Stage 1 of BFR (from images on talks) has MECO and stage sep about when F9 does. Stage 2 (BFS in this case) is always going to do most of the work.

If lower stages get any craft above ~2.5 km/s, then the boosters are no longer easy to recover, and have to be far more complex (and heavy).

[NSEP]

21 minutes ago, DAL59 said:

What about a BFR superheavy?  With 7-3-1 asparagus staging?  slightly sarcastic

Launch date: 4th of July

[Terwin]

2 hours ago, DAL59 said:

What about a BFR superheavy?  With 7-3-1 asparagus staging?  slightly sarcastic

For when you really *NEED* to loft something that weighs as much as the ISS and takes less then 1000m^3 all in one go

(at ~420tons, ISS could plausibly be lofted by 3 BFR-cargo launches)

[sh1pman]

 

[Scotius]

Hehehe. I would bring a sack of potatoes. Hermetically sealed and covered in thermal insulation. You never know when extra sack of potatoes might come in handy.

[Xd the great]

2 hours ago, Scotius said:

Hehehe. I would bring a sack of potatoes. Hermetically sealed and covered in thermal insulation. You never know when extra sack of potatoes might come in handy.

Potatoes are good , but you will get bored over time.

Worms.

Carrot. Did someone say that martian soil is probably suitable for carrots?

Fungus, mushrooms.

[magnemoe]

4 hours ago, Terwin said:

For when you really *NEED* to loft something that weighs as much as the ISS and takes less then 1000m^3 all in one go

(at ~420tons, ISS could plausibly be lofted by 3 BFR-cargo launches)

Yes, note that you can refuel in orbit so no need to launch fuel. its only an issue if you launch stuff who can not be broken down to pieces less than 150 ton. 
Nuclear reactors? note that you can add shielding in orbit if reactor is not started. 

[kerbiloid]

We have a whole thread devoted to the Martian baggage.