totm nov 2023 SpaceX Discussion Thread

[StrandedonEarth]

Perhaps they should be using elephants or grey whales for scale?

[Deddly]

But how did Vanamonde get on board?

4 hours ago, tater said:

 that banana for scale is actually much bigger than a real banana.

Which banana? The banana holding the banana, the banana being held by the banana or both bananas?

[tater]

28 minutes ago, Deddly said:

But how did Vanamonde get on board?

Which banana? The banana holding the banana, the banana being held by the banana or both bananas?

Dude for scale. The little banana is pretty large.

 

[Flavio hc16]

8 hours ago, grawl said:

There even is a banana, for scale !

Ho god, my meme days are coming back to haunt me...

And the funniest part is: SpaceX Banana is bigger than ULA's banana  

 

https://www.reddit.com/r/SpaceXMasterrace/s/MMFx9VS3ca

[Flavio hc16]

I will do a copypasta from my reddit post:

 

So, thinking from the rumor/news that Berger got us, about the cancellation of the SLS program. Not the block 2 (was never going to happen) or block 1b, even the block 1.

 This spurred the conversation about how to change the plans, and the fact that the rumor talked about SLS, and not Orion.

 IMHO Orion is here to stay for the foreseeable future ( 4-8 years), because making the architecture work with Dragon adds complexity and as of right now Orion is unique because is capable of direct-from-the-moon-reentry (allegedly). In 4-8 years we can probably let also Orion die

 And this the made everyone say " human rating a starship is a nightmare'

 IMHO... They are wrong.

And this time, the fact that SLS was designed they way it was will help us:

 Just stack the whole ( already built) Icps-esm-Orion-LES combo on top of a disposable starship.

 And what will help us with the human rating?

The fact that SLS was born with Solid rocket boosters and so to escape from that we have Orion with a stupidly overbuilt Launch Escape System

 This will mean that Spacex will make a starship stage disposable, that is basically SN5 with a 9 to 8.4 meters adapter, and then just stack the whole ICPS stack on top.

 You need to build an hidrogen facility, but pad 39A Had that, and making H2 from methane (CH4) isn't that hard. Ofc they will need to rework some plumbing on the tower, but IMHO people are making it way more problematic that it really is. We are talking SpaceX here, they move fast.

 IMHO they will have enough performance margin that they will be even able to reuse the booster.

 275 tons booster with 100 tons of remaining props has enought DV to land (1000ms)

 Reusable Booster gives the stack around 3.1 km/s of DV

The disposable starship (V2, 1500 tons of propellant), weighting in at 100 tons gives the whole ICPS/Orion stack (66tons) 8.7 km/s, this give you 11.5 km/s -+ 500 Ms/s for the naked starship to do a deep decor it burns

 This gives the whole ICPS/Orion stack 1500 m/s of DV more than SLS.

 SLS can be replaced quite easily, as rocket replacement goes.

 

 

Edit: on a 2nd thought, expending also the superheavy would actually give enough margin to send Orion to TLI without even an ICPS

Just two stages: expendable SuperHeavy + expendable Starship. Expendable SuperHeavy gives ~3.7 km/s of delta-v. 100t expendable Starship, 1500 propellant, 27t of Orion, Isp 370s, this gives 9.2 km/s of delta-v. Total delta-v is 12.9 km/s, enough to send Orion to the Moon.

 

This way we don't need to worry about running out of ICPS, no need to worry about LH2 at LC-39A, everything is much much easier.

 

 

Edited yesterday at 11:12 AM by Flavio hc16

[Nuke]

7 hours ago, tater said:

An earlier image had a worker in the frame near it—and that banana for scale is actually much bigger than a real banana.

the banana for scale thing i always thought was kind of dumb, because there is quite a big difference from an african wild banana and a plantain (which is good sliced, fried and used as a side for jerk chicken). its kind of a cursed unit of measure. perhaps as a radiation source, but im not sure how size affects banana radioactivity.

[Deddly]

Is that a metric banana, an imperial (US) banana or an imperial (UK) banana?

[darthgently]

7 hours ago, Deddly said:

Is that a metric banana, an imperial (US) banana or an imperial (UK) banana?

Who knows?  Could be either.   Another quandary, it could be in radians or degrees if going for arc length.

8 hours ago, Flavio hc16 said:

I will do a copypasta from my reddit post:

 

So, thinking from the rumor/news that Berger got us, about the cancellation of the SLS program. Not the block 2 (was never going to happen) or block 1b, even the block 1.

 This spurred the conversation about how to change the plans, and the fact that the rumor talked about SLS, and not Orion.

 IMHO Orion is here to stay for the foreseeable future ( 4-8 years), because making the architecture work with Dragon adds complexity and as of right now Orion is unique because is capable of direct-from-the-moon-reentry (allegedly). In 4-8 years we can probably let also Orion die

 And this the made everyone say " human rating a starship is a nightmare'

 IMHO... They are wrong.

And this time, the fact that SLS was designed they way it was will help us:

 Just stack the whole ( already built) Icps-esm-Orion-LES combo on top of a disposable starship.

 And what will help us with the human rating?

The fact that SLS was born with Solid rocket boosters and so to escape from that we have Orion with a stupidly overbuilt Launch Escape System

 This will mean that Spacex will make a starship stage disposable, that is basically SN5 with a 9 to 8.4 meters adapter, and then just stack the whole ICPS stack on top.

 You need to build an hidrogen facility, but pad 39A Had that, and making H2 from methane (CH4) isn't that hard. Ofc they will need to rework some plumbing on the tower, but IMHO people are making it way more problematic that it really is. We are talking SpaceX here, they move fast.

 IMHO they will have enough performance margin that they will be even able to reuse the booster.

 275 tons booster with 100 tons of remaining props has enought DV to land (1000ms)

 Reusable Booster gives the stack around 3.1 km/s of DV

The disposable starship (V2, 1500 tons of propellant), weighting in at 100 tons gives the whole ICPS/Orion stack (66tons) 8.7 km/s, this give you 11.5 km/s -+ 500 Ms/s for the naked starship to do a deep decor it burns

 This gives the whole ICPS/Orion stack 1500 m/s of DV more than SLS.

 SLS can be replaced quite easily, as rocket replacement goes.

 

 

Edit: on a 2nd thought, expending also the superheavy would actually give enough margin to send Orion to TLI without even an ICPS

Just two stages: expendable SuperHeavy + expendable Starship. Expendable SuperHeavy gives ~3.7 km/s of delta-v. 100t expendable Starship, 1500 propellant, 27t of Orion, Isp 370s, this gives 9.2 km/s of delta-v. Total delta-v is 12.9 km/s, enough to send Orion to the Moon.

 

This way we don't need to worry about running out of ICPS, no need to worry about LH2 at LC-39A, everything is much much easier.

 

 

Well done, and I’m betting highly predictive

11 hours ago, tater said:

Dude for scale. The little banana is pretty large.

 

Zoom in, banana is holding a more realistically scaled banana, ha

[tater]

29 minutes ago, darthgently said:

Zoom in, banana is holding a more realistically scaled banana, ha

The banana held by a banana is also holding a banana?

[darthgently]

53 minutes ago, tater said:

The banana held by a banana is also holding a banana?

Nope, thought you meant the big one.  Y’all must have smaller bananas or something!

[magnemoe]

10 hours ago, Nuke said:

the banana for scale thing i always thought was kind of dumb, because there is quite a big difference from an african wild banana and a plantain (which is good sliced, fried and used as a side for jerk chicken). its kind of a cursed unit of measure. perhaps as a radiation source, but im not sure how size affects banana radioactivity.

Yes its stupid, now an banana is not an horrible way to show the scale of something 10-40 cm long, and all is thinking standard bananas here not some special type who its lots of. 
But for something large its an nonsense measurement. 

[darthgently]

17 hours ago, Nuke said:

the banana for scale thing i always thought was kind of dumb

I gather that is the entire point.  That and it is the prime feedstock in the diet of spherical cows bred for research purposes.   Grass confounds the results and bananas don’t for complicated reasons.   I know, it surprised me too.

iirc, the banana for scale thing started in an off color way with the advent of selfies

[Vanamonde]

Some comments removed. Please remember to avoid politics. The subject is important, however, nobody seems to be able to discuss it without getting angry and turning it into bitter arguments. Please try to keep this as a friendly little space game forum away from all that unpleasantness. 

[tater]

About to land booster

[Exoscientist]

On 11/13/2024 at 4:37 AM, Flavio hc16 said:

I will do a copypasta from my reddit post:

 

So, thinking from the rumor/news that Berger got us, about the cancellation of the SLS program. Not the block 2 (was never going to happen) or block 1b, even the block 1.

 This spurred the conversation about how to change the plans, and the fact that the rumor talked about SLS, and not Orion.

 IMHO Orion is here to stay for the foreseeable future ( 4-8 years), because making the architecture work with Dragon adds complexity and as of right now Orion is unique because is capable of direct-from-the-moon-reentry (allegedly). In 4-8 years we can probably let also Orion die

 And this the made everyone say " human rating a starship is a nightmare'

 IMHO... They are wrong.

And this time, the fact that SLS was designed they way it was will help us:

 Just stack the whole ( already built) Icps-esm-Orion-LES combo on top of a disposable starship.

 And what will help us with the human rating?

The fact that SLS was born with Solid rocket boosters and so to escape from that we have Orion with a stupidly overbuilt Launch Escape System

 This will mean that Spacex will make a starship stage disposable, that is basically SN5 with a 9 to 8.4 meters adapter, and then just stack the whole ICPS stack on top.

 You need to build an hidrogen facility, but pad 39A Had that, and making H2 from methane (CH4) isn't that hard. Ofc they will need to rework some plumbing on the tower, but IMHO people are making it way more problematic that it really is. We are talking SpaceX here, they move fast.

 IMHO they will have enough performance margin that they will be even able to reuse the booster.

 275 tons booster with 100 tons of remaining props has enought DV to land (1000ms)

 Reusable Booster gives the stack around 3.1 km/s of DV

The disposable starship (V2, 1500 tons of propellant), weighting in at 100 tons gives the whole ICPS/Orion stack (66tons) 8.7 km/s, this give you 11.5 km/s -+ 500 Ms/s for the naked starship to do a deep decor it burns

 This gives the whole ICPS/Orion stack 1500 m/s of DV more than SLS.

 SLS can be replaced quite easily, as rocket replacement goes.

 

 

Edit: on a 2nd thought, expending also the superheavy would actually give enough margin to send Orion to TLI without even an ICPS

Just two stages: expendable SuperHeavy + expendable Starship. Expendable SuperHeavy gives ~3.7 km/s of delta-v. 100t expendable Starship, 1500 propellant, 27t of Orion, Isp 370s, this gives 9.2 km/s of delta-v. Total delta-v is 12.9 km/s, enough to send Orion to the Moon.

 

This way we don't need to worry about running out of ICPS, no need to worry about LH2 at LC-39A, everything is much much easier.

 

 

 

 Nice calculation. I’d like to get some feedback on these estimates I made after I heard Robert Zubrin say Elon told him the Starship, i.e., the upper stage only, could be made for ~$10 million production cost:

https://twitter.com/spacewatchgl/status/1855925836932841756

I was surprised that Elon estimates a Starship only cost of ~$10 million. At a ~$10 million Starship cost, SpaceX should investigate it as 1st stage of a smaller system, with a mini-Starship as the 2nd stage at perhaps only ~$2 million additional cost, due to its proportionally smaller size. Get ~100 ton to LEO Saturn V-class launcher at only ~$12 million cost(!) 

 As the first stage now, Starship loses only a proportionally small payload by reusing if you land it down range. Then close to a 100 ton partially reusable launcher for only ~$3 million(!) Say, payload reduced to 80 tons with partial reusability. Then price per kilo only $3 million/80,000kg = $37.5 per kilo(!)

  Bob Clark

[Exoscientist]

9 hours ago, tater said:

About to land booster

  

 How are you getting twitter links to embed?

  Bob Clark

[Deddly]

1 hour ago, Exoscientist said:

a mini-Starship as the 2nd stage at perhaps only ~$2 million

I don't think things are necessarily cheaper just because they are smaller. Compare, for example, the price of a good mobile phone with a good tablet or a laptop. 

A theoretical mini Starship (basically an X-37B,I suppose?) would still need the same parts and software development, so the only savings would be fuel and the volume of materials, which must be a pretty small fraction of that cost. Also, when Elon says something could be done in a certain amount of time or for a certain amount of money, it's almost always - as he puts it - aspirational and doesn't reflect any actual timeline or current cost.

[darthgently]

On 11/13/2024 at 1:57 AM, Deddly said:

But how did Vanamonde get on board?

Which banana? The banana holding the banana, the banana being held by the banana or both bananas?

It’s bananas all the way down

[Deddly]

7 minutes ago, darthgently said:

It’s bananas all the way down

Spoiler