totm nov 2023 SpaceX Discussion Thread

[StrandedonEarth]

13 minutes ago, KSK said:

He who does not properly research his references has forgotten the face of his father. But... back on topic.  

See the Raptor, ain't it keen? All things serve the SpaceX team...

*ducks and runs*

[CatastrophicFailure]

44 minutes ago, StrandedonEarth said:

See the Raptor, ain't it keen? All things serve the SpaceX team...

*ducks and runs*

 

Not like there’s much else to discuss at the moment, what with Block V static fire delayed another day.  

so does this make Bezos the Crimson Azure King?

[StarStreak2109]

At this stage all these "artists impressions" are IMHO of a notional character only. I'd say that if it happens, the final BFR (whatever it'll be called eventually), will look significantly different. But first it'll have to get beyond the PowerPoint stage and actually / literally get off the ground...

PS: I am not an engineer, but how they will get several tens of tons of potentially bulky cargo in and out of the cargo hold that high up, I cannot imagine. Of course on Moon and Mars, the gravity is lower, so you'd get a way with a smaller crane. But on Earth? And that cargo bay door pictured above may make sense for large satellite deployment, but again, I have my doubts it is practical. Too many points where cargo could bump into edges and stuff (what happens then with the heat shield?).

As I said, it'll probably redesigned half a dozen times before any (if any) prototype lifts off...

Edited May 1, 2018 by StarStreak2109

[StrandedonEarth]

6 hours ago, CatastrophicFailure said:

so does this make Bezos the Crimson Azure King?

Why yes, I think it does....

It would be great of some cartoonist could make a satirized showdown between the Musk the Gunslinger and the Bezos  the Azure King...

[NSEP]

Maybe they are going to test a mechanical arm system for the BFR on the Dragon?

There is also a possibility we are taking his drunk tweets to seriously.

[cubinator]

2 minutes ago, NSEP said:

 

There is also a possibility we are taking his drunk tweets to seriously.

Maybe, but Elon is notorious for following through on them.

[Delay]

5 minutes ago, NSEP said:

There is also a possibility we are taking his drunk tweets to seriously.

We're talking about Elon Musk here.

He will find a way to do what he wants to do.

[kerbiloid]

If they were having aerospike with a wide central body, they could just place an axial elevator inside the rocket.

Like in films about flying saucers: the ship lands, the heatshield covering the central body extends down, and we can see a door in a cylinder's side.

Like here, but aerospike.

Spoiler

 

Edited May 1, 2018 by kerbiloid

[Wjolcz]

4 hours ago, StarStreak2109 said:

At this stage all these "artists impressions" are IMHO of a notional character only. I'd say that if it happens, the final BFR (whatever it'll be called eventually), will look significantly different. But first it'll have to get beyond the PowerPoint stage and actually / literally get off the ground...

PS: I am not an engineer, but how they will get several tens of tons of potentially bulky cargo in and out of the cargo hold that high up, I cannot imagine. Of course on Moon and Mars, the gravity is lower, so you'd get a way with a smaller crane. But on Earth? And that cargo bay door pictured above may make sense for large satellite deployment, but again, I have my doubts it is practical. Too many points where cargo could bump into edges and stuff (what happens then with the heat shield?).

As I said, it'll probably redesigned half a dozen times before any (if any) prototype lifts off...

I dunno. I remember seeing one of these artist impressions of landing rocket boosters and thinking the same. Then they started landing these boosters for real. Having said that, I wouldn't be suprised too if it changed in some way.

If NASA could assemble Saturn V and can do the same with SLS (it will probably fly sooner than this one tbh) then SpaceX can probably assemble BFR and put the payload in it. Not like crane technology is super secret or illegal.

About that payload: what's wrong with taking the doors off, putting the payload in and then mounting them back on?

Cargo could bump into edges? I'm not sure if I understand. You could say the same about cargo being in fairing.

[NSEP]

Detaching a the cargo bay door might require a little bit of work but i do see it becoming practical in some cases. Another option might be for it to have shuttle like cargo bay doors.

[sevenperforce]

10 minutes ago, NSEP said:

Detaching a the cargo bay door might require a little bit of work but i do see it becoming practical in some cases. Another option might be for it to have shuttle like cargo bay doors.

Aye on the latter point, but that might limit payload volume because of the curvature around the nose.

Then again, BFS is not exactly volume-limited.

[CatastrophicFailure]

Ginormous cargo bay doors and a reliable way of manipulating payload on orbit with a reusable vehicle have all been done before. Seems to me this is one of the least of the engineering challenges facing BFS. Like @sevenperforce just said, volume and mass limits on this bird are a relatively minor concern, that gives SpaceX a lot of leeway to figure out something that merely works first, then make it elegant later. 

[StarStreak2109]

4 hours ago, Wjolcz said:

I dunno. I remember seeing one of these artist impressions of landing rocket boosters and thinking the same. Then they started landing these boosters for real. Having said that, I wouldn't be suprised too if it changed in some way.

Sure, it is best never to underestimate the will of those truly convinced by their own ideas.

Quote

If NASA could assemble Saturn V and can do the same with SLS (it will probably fly sooner than this one tbh) then SpaceX can probably assemble BFR and put the payload in it. Not like crane technology is super secret or illegal.

My impression was that SpaceX is going for the quick turn-around here. Maybe at some stage we'll get to see an animation showing the cargo loading process in detail. Right now it seems overly complicated and cumbersome to me. Just imagine you have to crane possibly delicate cargo some hundred meters up and into the cargo hold. So yeah, they probably have some super ingenious idea on doing it (wouldn't be surprised), which will amaze us all, when we see it. Right now I am just a bit sceptical about the practicality.

Quote

About that payload: what's wrong with taking the doors off, putting the payload in and then mounting them back on?

Nothing at all. Just that it probably isn't the quick turn-around that is advertised currently...

Quote

Cargo could bump into edges? I'm not sure if I understand. You could say the same about cargo being in fairing.

I was just thinking the following. You have this cargo bay, which goes up around the edges to allow for the heat shield to cover the areas affected by reentry. Then there's the cargo bay door, which is - at least in the render - not opening to 90° but somewhat less. Now you have to deploy the cargo, i.e. have it move out of the cargo bay. My point was that the egress way is somewhat constricted, more so than a payload mounted on a payload adapter. There the fairing does not matter, since it was jettisoned after leaving the dense parts of the atmosphere. Again my point is that I as a non-engineer would probably go for a solution with a less constricted egress way.

[tater]

 

[Wjolcz]

3 hours ago, StarStreak2109 said:

My impression was that SpaceX is going for the quick turn-around here. Maybe at some stage we'll get to see an animation showing the cargo loading process in detail. Right now it seems overly complicated and cumbersome to me. Just imagine you have to crane possibly delicate cargo some hundred meters up and into the cargo hold. So yeah, they probably have some super ingenious idea on doing it (wouldn't be surprised), which will amaze us all, when we see it. Right now I am just a bit sceptical about the practicality.

Meh. I wouldn't be too worried about that:

The shuttle was 8.7 meters in diameter.

3 hours ago, StarStreak2109 said:

I was just thinking the following. You have this cargo bay, which goes up around the edges to allow for the heat shield to cover the areas affected by reentry. Then there's the cargo bay door, which is - at least in the render - not opening to 90° but somewhat less. Now you have to deploy the cargo, i.e. have it move out of the cargo bay. My point was that the egress way is somewhat constricted, more so than a payload mounted on a payload adapter. There the fairing does not matter, since it was jettisoned after leaving the dense parts of the atmosphere. Again my point is that I as a non-engineer would probably go for a solution with a less constricted egress way.

I actually never thought about how they would load it, but if the cargo door opened at 90° they could probably just put it in horizontal position and load the cargo shuttle-style.

Edit: actually, why not have van-like doors. They would pop out and slide down keeping it out of the way of cargo while being lowered. Mechanism like this would probably add weight because the rail would have to be telescopic. But since it's meant to lift about 155t into LEO then they probably could get away with some additional weight?

Edit 2: Nevermind the telescopic rail. I forgot how sliding doors work. If the door had rails on itself they would only need a wheel rotating and moving it up or down.

Edited May 1, 2018 by Wjolcz

[kerbiloid]

Spoiler

9 hours ago, StarStreak2109 said:

Maybe at some stage we'll get to see an animation showing the cargo loading process in detail.

 

[Nibb31]

8 hours ago, Wjolcz said:

Meh. I wouldn't be too worried about that:

The shuttle was 8.7 meters in diameter.

The Shuttle took several days to mate/demate.

Not really rapid turnaround.

Payload integration is not like loading a truck. There are reasons why it typically takes weeks rather than hours.

 

[CatastrophicFailure]

 

[Jaff]

3 hours ago, CatastrophicFailure said:

 

Such a kerbal picture - I love it! 

[Wjolcz]

7 hours ago, Nibb31 said:

The Shuttle took several days to mate/demate.

Not really rapid turnaround.

Payload integration is not like loading a truck. There are reasons why it typically takes weeks rather than hours.

 

What if they had the payload in 'cages' of sorts. So you take the payload and it stands in that 'cage' in a warehouse for a couple of days, then when BFS lands you just open its cargo bay, take the empty 'cage' from the previous flight and load in a new one? Wouldn't that solve the issue of payload integration?

I'm not sure what to call the cage thing. I'll search the internet for something like it.

Edit: Ok so I guess I could also call it an evolved payload adapter or something like that. Basically anything that holds the payload and can be attached to the inside of the cargo bay in hours.

Edited May 2, 2018 by Wjolcz

[Barzon]

The shuttle had something similar to that. 

EDIT:

Found a link https://www.nasa.gov/mission_pages/shuttle/flyout/PCR.html about it.

Edited May 2, 2018 by Barzon Kerman

[NSEP]

14 minutes ago, Wjolcz said:

What if they had the payload in 'cages' of sorts. So you take the payload and it stands in that 'cage' in a warehouse for a couple of days, then when BFS lands you just open its cargo bay take the empty 'cage' from the previous flight and load in a new one? Wouldn't that solve the issue of payload integration?

I'm not sure what to call the cage thing. I'll search the internet for something like it.

Edit: Ok so I guess I could also call it an evolved payload adapter or something like that. Basically anything that holds the payload and can be attached to the inside of the cargo bay in hours.

Sounds like an interesting idea! Another advantage of this might be protection from bumping and crashing and a closed cage could maybe give protection from bacteria that can contaminate the payload. Maybe a closed version of the cage as a space-station module!

[Wjolcz]

2 hours ago, Barzon Kerman said:

The shuttle had something similar to that. 

EDIT:

Found a link https://www.nasa.gov/mission_pages/shuttle/flyout/PCR.html about it.

If I understand correctly this sounds kind of complicated. So they would put the payload in the container (PCR?) and then transport it to the shuttle on the pad and then transfer the payload from the container to the shuttle?

Sounds complicated but that's because, in the shuttle, every kilogram mattered so they couldn't simply just put it in with the container (which would probably make things easier). Given its LEO capability I don't think this will be a problem for BFS.

Edited May 2, 2018 by Wjolcz

[tater]

 

[wumpus]

3 hours ago, Wjolcz said:

What if they had the payload in 'cages' of sorts. So you take the payload and it stands in that 'cage' in a warehouse for a couple of days, then when BFS lands you just open its cargo bay take the empty 'cage' from the previous flight and load in a new one? Wouldn't that solve the issue of payload integration?

Hmm, I don't know.  Pallet, shipping container, how about orbit container?

Granted, assuming you are launching the cage, that "cage" costs at least a buck a gram for Falcon, but might make sense on BFR.  I wonder if you could make them "stackable", so you could buy a certain amount of vertical space relatively easily (I'm guessing not, unless you were willing to meet critical center of mass requirements and be willing to pay for ballast).

But if you want to really make shipping to space crank up into high gear, this is what you need (try imagining modern shipping without shipping containers).  Eat the efficiency loss (presumably with BFR or similar) and do it.