Skylon

SpaceX Discussion Thread

Recommended Posts

14 minutes ago, tater said:

They're a business, and they keep doing it. You don't lose money on each product, but make it up in volume, lol. Their investors see real data. I'm confident that reuse is a good idea (because it's self-evidently true that it is).

How bout we start a GoFundMe to see those numbers? (If law allows)

Share this post


Link to post
Share on other sites
3 minutes ago, Nothalogh said:

One thing you'll notice about all of Musk's side ventures, is that they all tie in to the end goal of SpaceX.

On another hand, all Musk's ventures have something similar: financial losses and fantasy plans, why SpaceX should differ?

Share this post


Link to post
Share on other sites
56 minutes ago, tater said:

Their investors see real data.

Maybe.  Try telling that to Disney investors right now.

You need to see enough financials *and* have an independent forensic auditor vet them.  Because if you're worried about deception, you need the right sort of magician to check for porkies.

Share this post


Link to post
Share on other sites
2 hours ago, kerbiloid said:

why SpaceX should differ?

And why should anyone dignify your disingenuous insinuations and outright absurdity with a response?

Share this post


Link to post
Share on other sites
2 minutes ago, Nothalogh said:

And why should anyone dignify your disingenuous insinuations and outright absurdity with a response?

Noone should. They should dignify available numbers. If any.

Share this post


Link to post
Share on other sites
Posted (edited)
5 minutes ago, kerbiloid said:

They should dignify available numbers.

You're asking for what nobody in the industry publishes, and then insinuating that lack thereof is proof that SpaceX is swindling everybody.

It's disingenuous, to say the least.

Edited by Nothalogh

Share this post


Link to post
Share on other sites
Posted (edited)
10 minutes ago, Nothalogh said:

You're asking for what nobody in the industry publishes, and then insinuating that lack thereof is proof that SpaceX is swindling everybody.

It's disingenuous, to say the least.

I'm afraid you've misunderstood.
I don't ask for the numbers, as I'm sure nobody knows them except several best people of SpaceX.
I just notice that there is no available numbers.
And the history teaches us that any secrecy usually hides absence or lack of something, rather than a presence of what can be stolen.
So, I just notice that there is just no available numbers on Falcon reusability and self-sustainability, no objective data, so any opinion about their success is based on believes.
As it's said above, a positive claim needs an evidence (or so). Space-X makes positive claims ("the stage is reusable", "the launch became cheaper"), but doesn't provide with any evidence.
So, of course you can bet on if this is so (maybe, it's really so), but a science deals with facts, not with claims. No facts.

Edited by kerbiloid

Share this post


Link to post
Share on other sites
1 hour ago, kerbiloid said:

I'm afraid you've misunderstood.
I don't ask for the numbers, as I'm sure nobody knows them except several best people of SpaceX.
I just notice that there is no available numbers.
And the history teaches us that any secrecy usually hides absence or lack of something, rather than a presence of what can be stolen.
So, I just notice that there is just no available numbers on Falcon reusability and self-sustainability, no objective data, so any opinion about their success is based on believes.
As it's said above, a positive claim needs an evidence (or so). Space-X makes positive claims ("the stage is reusable", "the launch became cheaper"), but doesn't provide with any evidence.
So, of course you can bet on if this is so (maybe, it's really so), but a science deals with facts, not with claims. No facts.

My guess is SpaceX is losing money. 

The reusable booster stunt hasn't been shown to save any money. To reuse a booster you must pay a lot of money in recovery and getting it back to flight. I think SpaceX has only reused boosters up to 3 times so that can't be enough to save money.

Elon Musk is wasting so much money on that dumb "Starship" rocket to nowhere that you know investors must be getting nervous. 

Even early this year SpaceX let go 10% of its workers so you know things can't be going great. I think SpaceX will have fewer launches this year too. 

Musk is probably driving SpaceX into a ditch of bankruptcy. Just like Tesla.

Share this post


Link to post
Share on other sites
Posted (edited)
20 minutes ago, Kerbal7 said:

The reusable booster stunt hasn't been shown to save any money. To reuse a booster you must pay a lot of money in recovery and getting it back to flight. I think SpaceX has only reused boosters up to 3 times so that can't be enough to save money.

It would be really odd if they kept recovering them instead of building new ones since reusability doesn't save you that much money.

That being said, Musk himself said that a rocket company is the opposite of profitable. I don't remember the exact quote but he was implying that you have to be really naive if you are starting one and your main goal is to make money.

At the same time: reusability is already studied by other companies and nations. So, maybe it's not that bad of an idea after all? If he was just a big reusability troll the math would show that's it's not profitable. Yet, we are about to see a lot of Falcon 9-like rockets with legs attached in the following decade. I'm sure the Chinese and Europeans can count money too.

20 minutes ago, Kerbal7 said:

Elon Musk is wasting so much money on that dumb "Starship" rocket to nowhere that you know investors must be getting nervous. 

AFAIK it's being paid, at least in part, by Maezawa. Does SpaceX even have any investors? I thought it was private, or something?

20 minutes ago, Kerbal7 said:

Even early this year SpaceX let go 10% of its workers so you know things can't be going great.

That doesn't mean they are on the brink of bankruptcy though. Maybe you need fewer people when you are mostly reusing rockets instead of building them? Maybe you don't need to produce X engines each week and instead you produce less than X because they aren't thrown away into the sea each time you launch? I can easily imagine maintenance needing much less people and resources than constant production.

20 minutes ago, Kerbal7 said:

I think SpaceX will have fewer launches this year too. 

Fewer compared to what exactly?

20 minutes ago, Kerbal7 said:

Musk is probably driving SpaceX into a ditch of bankruptcy.

Maybe he is. Maybe he isn't. All I care about is seeing people land on Mars before I'm old. And he seems to be the closest one to achieving this, it seems.

Edited by Wjolcz

Share this post


Link to post
Share on other sites
Posted (edited)

I guess, just the reusability can be a thing for bigger rockets, and when they:
1) do not disassemble the rocket between flights, like they don't do this in airports; and spend several hours, not several months;
2) the rocket is enough thick to be dumb;
3) the same human resources and their salaries are spent not for a 15 t payload flight, but for, say, 500 t.

I.e. just size matters.
I don't know if Starship is enough big and thick for reusability, but as I can see, it almost matches the GK-175/Energy-2 project pictured above, so I would expect its reusability is same doubtful.

Probably, only rockets with > 300 t payload make sense to be reusable, and rockets of 50..100 t may be reusable if do tens ;launches per years, just because you avoid melting a mountain of metal scrap.

3 minutes ago, Wjolcz said:

That being said, Musk himself said that a rocket company is the opposite of profitable.

Which one of his companies is not?

Edited by kerbiloid

Share this post


Link to post
Share on other sites
10 minutes ago, Kerbal7 said:

My guess is SpaceX is losing money. 

The reusable booster stunt hasn't been shown to save any money. To reuse a booster you must pay a lot of money in recovery and getting it back to flight. I think SpaceX has only reused boosters up to 3 times so that can't be enough to save money.

Elon Musk is wasting so much money on that dumb "Starship" rocket to nowhere that you know investors must be getting nervous. 

Even early this year SpaceX let go 10% of its workers so you know things can't be going great. I think SpaceX will have fewer launches this year too. 

Musk is probably driving SpaceX into a ditch of bankruptcy. Just like Tesla.

How can reuse don't save money? 
The engines is majority of the cost, the engines are also used many times before a launch because of static fires. 
Assume they refurbish the engines to be sure but this is still cheaper than making new ones.
50% saving sounds a little low to me, probably because lots of refurbish and testing to make sure stage is good as payloads tend to be much more expensive than the rocket. 
For starlink they can take more risks so can probably cut this. 

But yes their loosing money because they building two gigant rockets now. 

Rocketlab on the other hand don't think they will save so much on recovery, they rocket is much cheaper, engines are cheap because no turbo pump. However they can keep the launch frequency up 

Share this post


Link to post
Share on other sites
Posted (edited)
7 minutes ago, kerbiloid said:

Which one of his companies is not?

Is he still a co-owner of PayPal?

Edited by Wjolcz

Share this post


Link to post
Share on other sites
4 minutes ago, magnemoe said:

How can reuse don't save money? 

1. 2nd stage is not reusable. So, minus its cost.
2. 1st stage is heavier due to legs and other landing-related things (more complicated restartable engines). Requires more fuel.
3. 1st stage part should be more reliable. Not "0.97", but "0.99" probability, because 0.993 = 0.97, so instead of sending to trash 2 manufactured parts, they must 3 of them (after the primary control)
4. They need to deliver the stage (amortize the barge), disassemble (salaries, equipment amortization, energy), check everything (same, same, same).

3 minutes ago, Wjolcz said:

Is he still a co-owner of PayPal?

I don't know, but: he was a co-, not the.
PayPal doesn't manufacture something, it's a financial organization.

Share this post


Link to post
Share on other sites

Can we perhaps just open a topic to argue about spacex and say negative things so that we can use this one for updates and positive things?

 

I really feel like this topic has been going downhill and i used to enjoy reading this but now i don't.

Share this post


Link to post
Share on other sites
39 minutes ago, kerbiloid said:

1. 2nd stage is not reusable. So, minus its cost.
2. 1st stage is heavier due to legs and other landing-related things (more complicated restartable engines). Requires more fuel.
3. 1st stage part should be more reliable. Not "0.97", but "0.99" probability, because 0.993 = 0.97, so instead of sending to trash 2 manufactured parts, they must 3 of them (after the primary control)
4. They need to deliver the stage (amortize the barge), disassemble (salaries, equipment amortization, energy), check everything (same, same, same).

I like how some people in this thread go all "where's the data and numbers, they are not sharing it so obviously reusability doesn't work" then there's a post like this one without any data either somehow trying to prove it doesn't work.

So there's this post versus Shotwell's quote. But she obviously has things to hide, right?

We don't know. But they are pursuing it. Other companies do too. That's what matters since it seems to be driving costs down significantly.

43 minutes ago, kerbiloid said:

I don't know, but: he was a co-, not the.
PayPal doesn't manufacture something, it's a financial organization.

It doesn't matter. If he has a constant income from that then he can spend all that money on whatever he wishes.

Share this post


Link to post
Share on other sites
12 minutes ago, kerbiloid said:

1. 2nd stage is not reusable. So, minus its cost.
2. 1st stage is heavier due to legs and other landing-related things (more complicated restartable engines). Requires more fuel.
3. 1st stage part should be more reliable. Not "0.97", but "0.99" probability, because 0.993 = 0.97, so instead of sending to trash 2 manufactured parts, they must 3 of them (after the primary control)
4. They need to deliver the stage (amortize the barge), disassemble (salaries, equipment amortization, energy), check everything (same, same, same).

I don't know, but: he was a co-, not the.
PayPal doesn't manufacture something, it's a financial organization.

1 Second stage reach orbit so its goes much faster and is much harder to brake, its also much cheaper as its just one engine. 
2 this is true however most satellites don't 100% of an falcon 9 performance. If one does like an recent launch they use rocket disposable they can also use falcon heavy, the extra fuel is also nice if you lose one of your engines and need more fuel because lower TWR
3 this one I did not get, however its quite likely an reused stage is more reliable than an new one as an common cause for fails are manufacturing fails who was not spotted. 
Yes use also generate wear who can result in fails but most products has an bath tube graph where you have plenty of fails on new products then fail rate falls off before starting raising again as product get old. 

4 the recovery prosess should be easy to calculate the cost for, all the testing is hard to get figures for but is likely to go down as they get experience in who parts who tend to generate problems. 


 

Share this post


Link to post
Share on other sites
46 minutes ago, Wjolcz said:

I like how some people in this thread go all "where's the data and numbers, they are not sharing it so obviously reusability doesn't work" then there's a post like this one without any data either somehow trying to prove it doesn't work.

So there's this post versus Shotwell's quote. But she obviously has things to hide, right?

We don't know. But they are pursuing it. Other companies do too. That's what matters since it seems to be driving costs down significantly.

It doesn't matter. If he has a constant income from that then he can spend all that money on whatever he wishes.

Extremists get more extreme, not less, as they lose rational ground to stand on. The ones who can read and do the math fall away, accepting the facts, leaving only the "persecuted minority" who hold their beliefs against all logic.

Share this post


Link to post
Share on other sites
44 minutes ago, Wjolcz said:

I like how some people in this thread go all "where's the data and numbers, they are not sharing it so obviously reusability doesn't work" then there's a post like this one without any data either somehow trying to prove it doesn't work.

So there's this post versus Shotwell's quote. But she obviously has things to hide, right?

We don't know. But they are pursuing it. Other companies do too. That's what matters since it seems to be driving costs down significantly.

If an company is not public its rare that they show the budget as they have no reason to.
Let say they are down to 30% cost of disposable launch by now. If this is known you are likely to get some in congress demanding that NASA pay them less for launches 

Yes that is part of why launches is so expensive, back in the start some companies made huge profit launching for the air force. 
Limited number of companies who provided and they might well have talked. 
Pricing model changed to cost+ profit, however this made it no reason to cut costs, high cost might be better for launching company.

Share this post


Link to post
Share on other sites
Posted (edited)
53 minutes ago, magnemoe said:

1 Second stage reach orbit so its goes much faster and is much harder to brake, its also much cheaper as its just one engine. 

Second stage is not reusable, so its cost is not saved.

53 minutes ago, magnemoe said:

2 this is true however most satellites don't 100% of an falcon 9 performance.

So, it flies underloaded, but this isn't about the reusability. Any rocket would.
I mean, they have to make the stage for "25%? 50%?" heavier than it could be, but use it three times. And spend additional fuel per launch to lift the legs, fins, and other mechanics.
Also this needs more engines per launch, as in fact 1-2 of 9 carry not the cargo but the legs.
This takes away some (unknown) part of the saved money.

53 minutes ago, magnemoe said:

this one I did not get, however its quite likely an reused stage is more reliable than an new one as an common cause for fails are manufacturing fails who was not spotted. 

You need a type of rocket with 0.97 reliability. Its reliability consists of its part reliabilities (nuts, screws, panels, sticks, etc).

You can't adjust your metal-cutting machine to produce only reliable parts.
Metal, plastic, or resin have some defects, some parts get damaged, temperature conditions may vary during their storing, and so on.

So, you should take a manufactured detail (nut, stick, panel, etc), measure its, say, ultrasonic characteristic (resonant frequencies and so on) and compare to an ideal characteristics.
Then if, say, its resonant frequency differs from the ideal value less than for, say, 3%, you consider it enough reliable. Otherwise you treat it as unusable and either drop to a trashcan, or use for less important needs than a rocket.

Now you want to have your rocket reusable, and it should be not less reliable than the expendable one. You are going to use it for, say, 3 flights.
So, a single flight reliability should be 0.971/3 ~= 0.99.

But you can't say to your metal-cutting machine: "Since now, make the nuts more reliable!". She always does her best.
You have either to buy a better equipment (so, distribute its amortization cost between the future rocket flights), or scrap more manufactured parts, setting a new treshold for their primary control.
So, now you should sort out the manufactured nuts and bolts with resonant frequency differing from ideal not >3%, but >2%.
This means, instead of scrapping, say, 2 details of 10 manufactured, you have to drop 3 of 10 (which differ from ideal for 2.5%, now inappropriate).
But as you have first to manufacture them before scrapping, you anyway must include their cost in the flight cost, though you just scrapped them and didn't use.

So, the rocket reusability means either more expensive equipment and materials (giving less defective parts), or scrap more manufactured parts as defective. This is just inevitable.

Manufacturing a reusable rocket, you inevitably make more expensive every its part. The more additonal flights - the more expensive should be every nut.

This also raises a reusable stage cost, as you should still pay for the scrapped ones like for good ones.

53 minutes ago, magnemoe said:

the recovery prosess should be easy to calculate the cost for,

The recovery process currently looks like a half-year of job for tens of best engineers who probably have high salaries.
Maybe I'm wrong, but yet nobody have shown this isn't so with numbers.

44 minutes ago, magnemoe said:

If an company is not public its rare that they show the budget as they have no reason to.
Let say they are down to 30% cost of disposable launch by now. If this is known you are likely to get some in congress demanding that NASA pay them less for launches 

I absolutely agree that SpaceX has a right to not declare the numbers.
But this doesn't make these numbers known. I don't say, they are bad, I say they are unknown, so any guessing that they are good, is just a guessing based only on subjective believes.

This in turn raises a question: how to estimate the believability.
Someone considers the SpaceX managers words enough significant arguments to believe that the untold numbers are good.
Another one looks at Tesla and Hyperloop profitability, and stays sceptic.

Edited by kerbiloid

Share this post


Link to post
Share on other sites
17 minutes ago, kerbiloid said:

Second stage is not reusable, so its cost is not saved.

Falcon 9 second stage dry mass is 1/5 of that of a first stage. It also has nine times fewer engines. Should be around ~15% of the total rocket cost. Expending a second stage every time is not a major hit really.

Share this post


Link to post
Share on other sites
1 minute ago, sh1pman said:

Falcon 9 second stage dry mass is 1/5 of that of a first stage. It also has nine times fewer engines. Should be around ~15% of the total rocket cost. Expending a second stage every time is not a major hit really.

Everything listed above is a minor hit. The question is if the sum of minor hits exceeds the economy.

Share this post


Link to post
Share on other sites
Just now, kerbiloid said:

Everything listed above is a minor hit. The question is if the sum of minor hits exceeds the economy.

Ok, next point: legs and fins. They’re not that heavy. They add around 2 tons total to the first stage. Which is 425t full, 22t empty. I checked the payload penalty in my rocket calculator, and it’s really unnoticeable. 

Requires more fuel: what it means is that Falcon 9 expendable can launch 8ish tons to GTO, and around 6 with far droneship landing. BUT! There’s very few satellites heavier than 6 tons that need to go to GTO. Most of the time they’re much lighter. And if it’s not GTO but LEO or SSO, then reusable F9 can launch practically anything that can fit into its fairing. 15t reusable payload limit to LEO, there’s no sat even remotely as heavy in existence.

 

Share this post


Link to post
Share on other sites

@kerbiloid and nothing beats the simple argument: if it wasn’t profitable, they wouldn’t be doing it. They’re business after all, not a charity, not a roscosmos. Keeping two drone ships, a huge recovery fleet, investing god knows how much into reusability R&D and Falcon upgrades. I imagine it all costs quite a bit. So the fact that they’re doing it, and haven’t gone broke yet, suggests that their math works.

Share this post


Link to post
Share on other sites
Posted (edited)
26 minutes ago, sh1pman said:

Ok, next point: legs and fins. They’re not that heavy. They add around 2 tons total to the first stage. Which is 425t full, 22t empty.

Add 9 heavier (restartable and reusable) engines and the fuel to accelerate them.
Then add several tonnes to stop the horizontal motion after separation and to accelerate back, the for aerobraking (without the shield, so afaik the engines are partially on) and landing.
Will it in total add ~20 t? Here you get at least +5%. A minor loss, too.

Then add the reassembling and testing procedures. We don't have numbers (as usually), but if, say 20 engineers are doing this for 5000 USD/month (I don't know Texas salaries, it's random) for 6 months, it's already 0.6 mln.
As they are using equipment and spending energy, probably we can presume 2..3 mln in total, so another +5%.

As the detailes should be manufactured more reliable than for a single use (99% vs 97%) we can probably add at least +20% (I would not be surprised if +50%, though) for the hardware cost itself.

So, the question is if unknown_value (15% + 5%? + 5%? + 20%? + other %s) lesser than another unknown_value (told ">50%").
I would presume these values are just comparable, so the reusability of such lightweight rocket is just between the "loss" and "profit".

26 minutes ago, sh1pman said:

Requires more fuel: what it means is that Falcon 9 expendable can launch 8ish tons to GTO, and around 6 with far droneship landing. BUT! There’s very few satellites heavier than 6 tons that need to go to GTO. Most of the time they’re much lighter.

The underloading is even worse. They spend 1 flight of possible 3 and can't change this by using a lighter vehicle.

15 minutes ago, sh1pman said:

if it wasn’t profitable, they wouldn’t be doing it.

https://www.theverge.com/2019/4/24/18514427/tesla-q1-2019-loss-model-3-elon-musk-earnings

https://www.torquenews.com/1083/tesla-lost-about-billion-dollars-2018-there-good-news

Like these ones (every year)? Unlike the Mars, this is actually a business.
Making the things doesn't mean this is profitable. Rockets as well.

Edited by kerbiloid

Share this post


Link to post
Share on other sites
3 minutes ago, kerbiloid said:

Add 9 heavier (restartable and reusable) engines and the fuel to accelerate them.
Then add several tonnes to stop the horizontal motion after separation and to accelerate back, the for aerobraking (without the shield, so afaik the engines are partially on) and landing.

Heavier, Merlins? lol. They have godlike thrust to weight and thrust to cost ratios. They are VERY light. Everyday Astronaut did a video with numbers about different engines, but in short, Merlins mass is definitely not a problem.

About extra fuel I said already. It’s about 10-15% of fuel reserved for braking and landing. Not an issue in 90% of actual real launches. 

11 minutes ago, kerbiloid said:

The underloading is even worse. They spend 1 flight of possible 3 and can't change this by using a lighter vehicle.

I don’t understand this. What do you think is cheaper? One 747 flight but paid for entirely by one person, or a small but expendable private jet Cessna that you throw away after the first flight?

17 minutes ago, kerbiloid said:

Like this one? Unlike the Mars, this is actually a business.

You didn’t address my argument at all, please do

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.