totm nov 2023 SpaceX Discussion Thread

[sh1pman]

6 minutes ago, YNM said:

I'm referring to yours and @sh1pman as well.

Great Western ~ F9

Great Britain ~ FH

Great Eastern ~ BFR

Engineering-wise the last in the series are the best most possible. But economy-wise you need them to be somewhat full. Sending them with only a puny 3* 3U cubesat in it won't work, as was 3000 pax's Great Eastern with only 38 passengers onboard flopped.

Great engineering maybe, great economics it's not.

Any payload that's profitable to launch on a single F9, will be even more profitable on BFR, if their infographics is to be believed.

[YNM]

Just now, sh1pman said:

Any payload that's profitable to launch on a single F9, will be even more profitable on BFR, if their infographics is to be believed.

Read up history then.

[sh1pman]

12 minutes ago, YNM said:

Read up history then.

Can you just make your point without giving vague examples from more than a century ago that may or may not be relevant to BFR? 

I have no reason not to trust SpaceX's cost-per-launch estimates.

[YNM]

1 hour ago, sh1pman said:

Can you just make your point without giving vague examples from more than a century ago that may or may not be relevant to BFR? 

I have no reason not to trust SpaceX's cost-per-launch estimates.

(sorry for ranting... )

You have to realize the meaning of BFR.

"Big [BLEEP]in' Rocket".

Now, take into account these :

- Is a smaller rocket more expensive to make than a bigger one ? (should be clear)

- Is a smaller rocket more complex than a bigger one ? (should be clear)

- Is a smaller rocket more cost effective than a larger one ?

 

Of the 3, the last answer can vary wildly.

Now, some more basic economy question :

- Which one is cheaper per passenger, a flight on an all-standing crammed-full 747 or a 747 private jet ?

- Which one is cheaper for me to buy as a private boat, a dinghy or a cruiseliner ?

You'll see that the answer is clear : more carrying capacity, more better. More fitting-form to payload, more better.

Next question :

Which one is cheaper to make, a car made of steel or a car made of paper ? (the answer should be clear along with the expectation of what it affects)

One last question :

Which one is cheaper per journeys, a boat made of paper that can be only used once, or a boat made of slightly thicker paper that lasts 2 usage ?

The answer varies wildly; but we can see in rocketry the latter tends to be cheaper (F9 is pilot example).

 

Here is the real key to answer whether BFR is really far cheaper than F9 or Saturn V.

BFR is larger than Saturn V and F9.

> It's more expensive to build.

> It's more expensive to run (mind the emphasis - running costs != sunken costs).

> It can carry more stuff.

>> Extra difference is that it can be reused.

Now, presuming that this are the case, then :

● It is more expensive to make

BUT

○ It can spread it's costs over more payload.

Now, there's a limit in choosing how to spread them : Time vs. quantity.

In general, it takes more effort to make things lasts than to make them absolute big-ss.

BFR is threading around this threshold. -> Let's say it can handle 30 flights, after the threading.

Now, it's designed for 150,000 kg of payload each launch.

But what if there's only 3,000 kg of payload for each launches ?

# Number of payload to spread actually : 150,000 * 30 = 4,500,000 kg

# Number of actual payload to spread :

3,000 * 30 = 90,000 kg

So now, each payload has to pay :

(4,500,000/90,000) = 50x the projected cost.

 

 

 

It's basic arithmatics.

 

Now obviously they have a break-even margin. But we just don't know where.

But 10,000 kg GEO/GSO spacecrafts isn't it given the 150,000 kg projected capacity. That's only 7%.

 

That was exactly what happened to the SS Great Eastern, dear @sh1pman. Brilliant idea, superb calculation, but with only 38 passenger out of projected 3000, it flops.

Edited February 19, 2018 by YNM
sorry for the rant ! seriously !

[tater]

@YNM No, the cost to run it is the per use cost of the vehicle: (mfg cost, and amortized share of dev cost)/flights + (cost of operations) + (cost of propellants)

I did the math for the original ITS, then scaled it down a little someplace here once. I figured that the total cost to launch a BFS to orbit was around 2 million $.

That's still cheaper, even just launching 3000kg as the only payload.

Also, BFS is an SSTO for tiny payloads. Where tiny for BFS is ~10 tons.

So the launch cost could in fact be far lower than 2 M$, if they could service small payloads without the booster.

[YNM]

1 minute ago, tater said:

No, the cost to run it is the per use cost of the vehicle: (mfg cost, and amortized share of dev cost)/flights + (cost of operations) + (cost of propellants)

No refurb ?

How cheap a manufacturing are we talking about ? They're not just scaling a Coke can upwards right ?

[PB666]

Looks to me like we are diving into a deep pool of speculation.

A 737-800 is more complicated than a 737-100 although weights are not terribly different. An airbus A350 is more complicated than a 747-100 even though the 747 is bigger. This is simply due to the fact that we have complicated miniaturized electronics that we did not have when 747-100 was designed in the late 60's. But even at that an old airline might be upgraded with new features, satellite telephone system, in seat entertainement systems, smoke detectors, . . . . . . . 

I could think of a BFS shell that is only slightly more complicated than an F9, I suppose that the refueler will be like this.

[Jaff]

2 minutes ago, tater said:

@YNM No, the cost to run it is the per use cost of the vehicle: (mfg cost, and amortized share of dev cost)/flights + (cost of operations) + (cost of propellants)

I did the math for the original ITS, then scaled it down a little someplace here once. I figured that the total cost to launch a BFS to orbit was around 2 million $.

That's still cheaper, even just launching 3000kg as the only payload.

Also, BFS is an SSTO for tiny payloads. Where tiny for BFS is ~10 tons.

So the launch cost could in fact be far lower than 2 M$, if they could service small payloads without the booster.

So surely a larger payload ~20-30t that’s too heavy for the top bit to ssto and nowhere near the 150t possible is a waste of a bfr launch? 

 

Ie something a Falcon heavy or a mini bfr whatever the next big thing is is preferable (reusable too of course)

[Starman4308]

3 minutes ago, YNM said:

No refurb ?

How cheap a manufacturing are we talking about ? They're not just scaling a Coke can upwards right ?

That's essentially the plan: make BFR so robust it can go for a fair number of flights without significant refurbishment, and reuse the same vehicle for hundreds to thousands of flights.

I have my doubts as to whether they'll reach the critical thresholds in terms of ease of reuse and booster loss rate, but if you take Musk's projected values at face value, the economics work out.

Just now, Jaff said:

So surely a larger payload ~20-30t that’s too heavy for the top bit to ssto and nowhere near the 150t possible is a waste of a bfr launch? 

 

Ie something a Falcon heavy or a mini bfr whatever the next big thing is is preferable (reusable too of course)

It's a waste of a BFR launch in much the same way as putting a single passenger onto a 747 is a waste.

It is, however, less of a waste than putting that single passenger onto a Cessna that flies only once before getting discarded. The BFR will be overkill, but hopefully reusable overkill, and that's what will drive down the cost of space access even further... assuming SpaceX can get it to work the way they want.

Edited February 19, 2018 by Starman4308

[YNM]

30 minutes ago, Scotius said:

Don't overestimate any governing body's willingness to make tough calls. If it weren't the case, car transportation would be banned decades ago

Haven't you read the history on speed limits during the "Steam Locomotive" era ?

http://www.cbrd.co.uk/articles/limit/not-so-fast

Quote

The heady days of tearing around at a breakneck 10mph were short-lived. Just four years later, the Locomotive Act 1865 lowered speed limits to just 4 and 2mph. Presumably drivers would be convicted of speeding if a policeman couldn't overtake the engine at a gentle stroll.

The 1865 Act also introduced someone who, to this day, is oddly imprinted on the popular imagination: the red flag man. A 2mph limit meant that locomotives would often reach their destination faster by parking up and waiting for continental drift to take its course, but were still considered such an unimaginable danger that a man was obliged to walk 60ft (18m) ahead of them holding a red flag. The law is referred to, even now, as the "red flag act".

 

7 minutes ago, Starman4308 said:

That's essentially the plan: make BFR so robust it can go for a fair number of flights without significant refurbishment, and reuse the same vehicle for hundreds to thousands of flight

But how cheap ?

You know we have talked about Big Dumb Boosters in this very part of forum before. Which one would be better ?

 

Seriously, understand my "rant" (sorry ! absolute sorry !) or learn about Great Eastern. I smell a burn of economic-viability-misconduct.

Edited February 19, 2018 by YNM

[Jaff]

7 minutes ago, Starman4308 said:

That's essentially the plan: make BFR so robust it can go for a fair number of flights without significant refurbishment, and reuse the same vehicle for hundreds to thousands of flights.

I have my doubts as to whether they'll reach the critical thresholds in terms of ease of reuse and booster loss rate, but if you take Musk's projected values at face value, the economics work out.

It's a waste of a BFR launch in much the same way as putting a single passenger onto a 747 is a waste.

It is, however, less of a waste than putting that single passenger onto a Cessna that flies only once before getting discarded. The BFR will be overkill, but hopefully reusable overkill, and that's what will drive down the cost of space access even further... assuming SpaceX can get it to work the way they want.

By that analogy if Virgin Atlantic know that their Heathrow to New York flight is rammed they use a 747, and their Heathrow to Washington is barely used they use a 767 shouldn’t it be he same for space x, assuming all space x rockets are reusable like 747s and 767’s are. Big 100t payload = bfr - not so big 20t payload FH - smaller 10t payload F9 or SSTO bfr 

[ment18]

3 minutes ago, Jaff said:

So surely a larger payload ~20-30t that’s too heavy for the top bit to ssto and nowhere near the 150t possible is a waste of a bfr launch? 

 

Ie something a Falcon heavy or a mini bfr whatever the next big thing is is preferable (reusable too of course)

No, because full re-usability.  There is a huge difference between throwing away 10% of your rocket and 0%.  A smaller fully reusable rocket is not that much cheaper than a large one, and the development costs are going to be very similar.  Why would SpaceX spend billions of dollars to make a smaller BFR, when they will only save maybe a few million per launch, and their goal is to get people to make bigger payloads?  

Falcon family cannot remotely compete.  They are not large enough to have an efficient 2nd stage reuse, and cannot land on their launch mounts.  They require much more refurbishment than a larger rocket designed with their knowledge of re-usability and at least one booster needs to land on barges for significant payloads.

[Technical Ben]

I seriously hope nothing was hiding in that Tesla like they tried to hide many years ago using a different millionaire. http://www.bbc.co.uk/news/resources/idt-sh/deep_sea_mining

[Jaff]

1 minute ago, ment18 said:

No, because full re-usability.  There is a huge difference between throwing away 10% of your rocket and 0%.  A smaller fully reusable rocket is not that much cheaper than a large one, and the development costs are going to be very similar.  Why would SpaceX spend billions of dollars to make a smaller BFR, when they will only save maybe a few million per launch, and their goal is to get people to make bigger payloads?  

Falcon family cannot remotely compete.  They are not large enough to have an efficient 2nd stage reuse, and cannot land on their launch mounts.  They require much more refurbishment than a larger rocket designed with their knowledge of re-usability and at least one booster needs to land on barges for significant payloads.

I understand that but when most payloads these days are nowhere near 150t what’s the point? Surely it’s cheaper to keep wasting Falcon upper stages?

 

its a bit chicken and egg though? Make a big rocket in the hope people make big payloads, or make big payloads and design the rocket to lift them 

[magnemoe]

6 minutes ago, Starman4308 said:

That's essentially the plan: make BFR so robust it can go for a fair number of flights without significant refurbishment, and reuse the same vehicle for hundreds to thousands of flights.

I have my doubts as to whether they'll reach the critical thresholds in terms of ease of reuse and booster loss rate, but if you take Musk's projected values at face value, the economics work out.

It's a waste of a BFR launch in much the same way as putting a single passenger onto a 747 is a waste.

It is, however, less of a waste than putting that single passenger onto a Cessna that flies only once before getting discarded. The BFR will be overkill, but hopefully reusable overkill, and that's what will drive down the cost of space access even further... assuming SpaceX can get it to work the way they want.

This, yes the BFR is far larger than it need to be but an fully reusable metanol fueled rocket capable of putting up full sized communications satellites would still be large, larger than New Glenn and Musk has an agenda who require an oversize rocket.
An smaller launcher would be more economical but this rocket don't exist.
Closest we get would be new Glen with an reusable upper stage who should work if the 40 ton capacity is with reuse of first stage who makes sense. If that is true 

Main question is if BFR is robust enough for rapid and long term reuse. The good side is that they have lots of margins if weight goes up
 

[Elthy]

I think the biggest challenge in getting the economics work out lay in the heatshield. Its propably the limiting factor in reuses before refurbishment and its durability/servicability will determine most of the running costs. When SpaceX can show me a heatshield that either lasts dozens of reentrys (and doesnt wheight tons like the spaceshuttle one) or is easily replaced (on a gigant spacecraft) im sold...

[ment18]

Just now, Jaff said:

I understand that but when most payloads these days are nowhere near 150t what’s the point? Surely it’s cheaper to keep wasting Falcon upper stages?

 

its a bit chicken and egg though? Make a big rocket in the hope people make big payloads, or make big payloads and design the rocket to lift them 

Its not cheaper.  BFR will cost 1-10 million, falcon family cost 60-100 million.  It is chicken and egg.  SpaceX is biting the bullet because their purpose it to develop humanity into a much more capable spaceflight species, not to make the most profit possible from the status quo.  Yes, SpaceX will spend many billions of dollars to make BFR, but BFR will revolutionize spaceflight and that is what everyone at SpaceX is there to do.

[Jaff]

1 minute ago, ment18 said:

Its not cheaper.  BFR will cost 1-10 million, falcon family cost 60-100 million.  It is chicken and egg.  SpaceX is biting the bullet because their purpose it to develop humanity into a much more capable spaceflight species, not to make the most profit possible from the status quo.  Yes, SpaceX will spend many billions of dollars to make BFR, but BFR will revolutionize spaceflight and that is what everyone at SpaceX is there to do.

 

Dont get me wrong I admire it,  it I’m also a skeptic and don’t think I will see mars landings in my lifetime (and I’m not even 30 yet) let alone musk in his lifetime. So profitability must be top of the agenda to pave the way for the next generation of space travelers. So less rocket launches for me = less enjoyment of my lifetime 

 

yes I’m selfish 

[Starman4308]

16 minutes ago, Jaff said:

Surely it’s cheaper to keep wasting Falcon upper stages?

No. Each Falcon upper stage is still probably on the order of ~$10 million to build.

Compared to that, fueling up a BFR is peanuts.

[Terwin]

Just now, Jaff said:

 

Dont get me wrong I admire it,  it I’m also a skeptic and don’t think I will see mars landings in my lifetime (and I’m not even 30 yet) let alone musk in his lifetime. So profitability must be top of the agenda to pave the way for the next generation of space travelers. So less rocket launches for me = less enjoyment of my lifetime 

 

yes I’m selfish 

Why fewer launches when star-link will happily send up an extra 100-200(40t-80t) satellites as a secondary payload?

How else will they get to 12K satellites in orbit?

Even assuming a 10yr life-span on these VLEO satellites, that still means ~1200/year or ~100(~40t)/month of already booked secondary payloads(probably closer to 80t)

 

And if they get the manned BFR working, that could be less than 150K per couple to honey-moon for a week in space($10M launch /75 couples=$133K)

[YNM]

Just now, Terwin said:

Why fewer launches when star-link will happily send up an extra 100-200(40t-80t) satellites as a secondary payload?

I think you need more unique orbits than that.

 

Alright, if BFR isn't meant to be economical, you can even charge a tenner, but if it'meant to be economical, I still don't see how it's not going to be somewhat astronomical which means astronomical payloads are needed too.

[Terwin]

10 minutes ago, YNM said:

I think you need more unique orbits than that.

 

Alright, if BFR isn't meant to be economical, you can even charge a tenner, but if it'meant to be economical, I still don't see how it's not going to be somewhat astronomical which means astronomical payloads are needed too.

If you can afford to double the weight of your satellite for extra fuel capacity, it seems likely that the satellite could have a lot more lee-way in where it is dropped off and still get to it's preferred orbit.

 

Indeed the costs are astronomical, but not nearly as astronomical as everyone is currently paying to get anything into space.

When everyone is accustomed to paying $60M+ to get something into space, if you can do it for <$10M, you can undercut everyone else at $50M and still have >400% profit/investment recoup per launch.  Even if you are only launching something that would fit on a F9B3 with RTLS.(making those extra 100 double-weight star-link satellites basically free to get into LEO as a secondary, unless you already have a secondary which means even more profit per launch)

 

Note: if/when someone else gets a smaller fully-reusable rocket working, SpaceX may well have a more limited clientele,  but unless/until that happens, SpaceX will be basically printing money with every launch, and even after it happens, people will have had enough time to have designed bigger sattelites to make full use of the BFR capacity, so the market will probably not completely disappear(satellites are expensive to design and build($$B), so why not throw on an extra-large fuel tank if it makes it last that much longer in space, it will save money in the long run, especially if the marginal cost is trivial($$M))

Edited February 19, 2018 by Terwin

[Green Baron]

Depends on its intended use. If it is used to haul heavy stuff up for money then that is an economic act. If it is used to ship paying people to Mars than that has at least an economic coat. Whether its a good bargain for both sides remains to be seen ;-)

But first of all, it must be built. How long does it usually take to develop a spaceship ? A decade ? They started last year, so here's my bet on the time of the first successful missions, 2027.

Edited February 19, 2018 by Green Baron

[sevenperforce]

18 hours ago, CatastrophicFailure said:

So speaking of this... the concept of "man-rating" gets thrown around a lot, here. Obviously NASA has some very specific standards SpaceX has to live up to due to the contract, but if SX did want to man-rate the FH, independently of NASA, what would that involve? As far as I know, there's no FAA or other "legal" standard for man-rating a rocket for entirely private use.

I'm not 100% on this, but my understanding is that SpaceX itself actually volunteered for a 5-flight man-rating process because that was easier and quicker for them than going through an extensive modeling and analysis program. Other launch providers change the launch vehicle configuration from flight to flight (different number of boosters, etc.) to handle changing payload requirements, but SpaceX has a single vehicle configuration and meets payload requirements by adjusting reuse (from RTLS, which is very inexpensive, to boostback-ASDS, which is slightly more expensive, to no-boostback-ASDS, which is more expensive, to expendable). It costs SpaceX virtually nothing to man-rate Falcon 9 Block 5 this way.

I don't think there is any man-rating standard for private spaceflight.

15 hours ago, Kerbal7 said:

Even if he could get past all the massive engineering problems and find the money it wouldn't make sense.

What "massive engineering problems" are you thinking of, exactly? Lifting-body entry has been tested extensively with the Shuttle. SpaceX already has firsthand experience with blunt-lifting-body entry. Supersonic retropropulsion is figured out. BFR is smaller-diameter than Saturn V.

Quote

Even if a BFR is built, the plan is to refuel it after landing on Mars from local resources. Okay, so now before you even land a single BFR on Mars, you've got to build a substantial infrastructure on Mars.You're going to need some sort of big processing plant to produce the liquid oxygen and liquid methane rocket fuel. You'll need to build massive storage and refueling facilities too. Pipes, pumps tanks, the whole 9 yards. All of this would be a difficult construction on Earth and you want to do it on Mars! And how's all this material getting down to the surface of Mars so you can even start construction?

This makes me think you haven't even paid attention to the actual plans. The first few BFSs will be one-way and unmanned, and will carry a rudimentary ISRU rover and associated equipment that will be craned down to the surface. 

Quote

In orbit refueling has never even been done before and that's needed for this BFR plan too.

The Progress spacecraft has routinely refueled the Space Station through fluid transfer connections around the perimeter of the docking ring. It's been done. SpaceX has a solid plan to make it more effective.

But don't forget: even without the Mars aspirations and orbital refueling, the BFR/BFS system would be the most cost-effective LEO access vehicle in history. Cheaper per-flight than Falcon 1.

 

[sevenperforce]

14 hours ago, PB666 said:

Question: If BFR is to replace falcon and dragon. How do they plan to return the orbital vehicle back to Earth, all I that I have seen is there intent to land on Mars. I have just been under the assumption that once the orbital vehicle goes up, it will simply never come back to Earth (either via refueling, etc)

No, nothing like that. The BFS reaches orbit with significant fuel reserves. It deploys its payload, fires for a deorbit burn, conducts a biconic re-entry, and stall-flips to land on its tail and landing legs.

That's the reason for those winglets, actually. It's possible for the BFS to do what it needs to do on body lift alone, but not if it has to deal with entry on both Mars and Earth with a range of entry velocities. Winglets add enough aerodynamic control to handle that wide range.