Skylon

SpaceX Discussion Thread

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12 minutes ago, PB666 said:

Generally something to be avoided, ETOPs is a specification for single engine failure over water, for example a mid pacific glide to water landing is the same as a crash, few survivors expected. The hudson river is a bonafida runway, used to be used in the days of transatlantic flights, the pacific ocean is not.

The difference between space flight and air flight is that the risk is high, but you don't do it very often. For aircraft the risk is low and people travel alot. The risk of spaceflight still exceeds that of flight, but one expects that risk to fall over time as we learn more about how to manage risk. Where have we seen this problem before, with flight. Crashes of Airplanes back in the 70s was much more common today (in the west), but has gone down over time do to increased use of aircraft. But before the 70s . .going back to the 1930s . . .it was pretty dangerous.

It's about managing mitigatable risk and maximizing benign failure modes. Complete loss of power on a transpacific flight is not a mitigatable risk; if that happens, everyone is sharkbait whether they have parachutes or not. It's the same as a large meteor impact on orbit; there's no way to survive it, so there's no sense trying to mitigate it.

You also don't need to mitigate benign failure modes. A 747 with loss of power on landing is a big emergency to be sure, but it has a nominal recovery mode: land deadstick. Thus, no need to mitigate. Loss of power on landing in a BFS is not at all benign, but you CAN mitigate it with an abort capsule and chutes.

14 minutes ago, tater said:

I honestly think the “killer app” for commercial space is tourism. As has been said, most everything is better done by telepresence than humans (and chraper). 

If safety can get to early airline levels, which is still substantially more dangerous than current travel, then the market could grow if the price was also not impossible. Safer still and it becomes a huge, bottomless market (since there will always be new people wanting to experience it).

I don’t think it’s close, but it’s the only economic driver I see that involves decent numbers of people.

Only if maximizing the comsat market lowers access prices by orders of magnitude.

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Yeah, price for people to space needs to be at most like first class international travel for it to become a decent market. 

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12 minutes ago, tater said:

Yeah, price for people to space needs to be at most like first class international travel for it to become a decent market. 

Still, you need a destination that's not just "float around for a few hours or days".

BFR would be able to orbit components for a space hotel in just a couple of launches. How much do cruise ship companies lay out for a new cruise ship?

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main-qimg-2cf1055d57597eaf51161dcf9ec82e

Clearly a smaller passenger load per dollar. Still, not impossible.

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1 hour ago, tater said:

Yeah, price for people to space needs to be at most like first class international travel for it to become a decent market. 

I'm surprised noone else has mentioned this before... IF (big IF) you can get the cost of even a low dV but safe rocket down that low then you open up a brand new market.

Concord may have been nice and all, but it was pretty slow. For less dV, less fuel, less speed, less reentry heating, less price - than LEO you can make a suborbiter that can do USA to Europe in less than an hour from embarking to disembarking. Yes, you need to build your launchpad somewhere with quick access to a major city, and where falling rockets wont kill people and ascending rockets wont disrupt planes too much.

Still likely to be a huge market. I would go so far as to suggest that if you can do LEO for a first class price you can do suborbit for not much more than economy price.

Oh, and I'm in China until tomorrow with my Chinese girlfriend. I have some understanding of Chinese culture. Believe me there are a LOT of rich people here and also believe me that rich Chinese are even more stupid with wasting their money than rich westerners. So you can add China to USA and China to Europe as well to that market. (assuming that the government here hasn't stolen the plans and built their own)

EDIT- I know we are talking about a lot more than an airfare at the moment but like i said - rich people stupid deep pockets. I mean how much was a Concorde ticket anyway?

Edited by Antstar

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9 minutes ago, Antstar said:

I'm surprised noone else has mentioned this before... IF (big IF) you can get the cost of even a low dV but safe rocket down that low then you open up a brand new market.

Concord may have been nice and all, but it was pretty slow. For less dV, less fuel, less speed, less reentry heating, less price - than LEO you can make a suborbiter that can do USA to Europe in less than an hour from embarking to disembarking. Yes, you need to build your launchpad somewhere with quick access to a major city, and where falling rockets wont kill people and ascending rockets wont disrupt planes too much.

Still likely to be a huge market. I would go so far as to suggest that if you can do LEO for a first class price you can do suborbit for not much more than economy price.

Oh, and I'm in China until tomorrow with my Chinese girlfriend. I have some understanding of Chinese culture. Believe me there are a LOT of rich people here and also believe me that rich Chinese are even more stupid with wasting their money than rich westerners. So you can add China to USA and China to Europe as well to that market. (assuming that the government here hasn't stolen the plans and built their own)

EDIT- I know we are talking about a lot more than an airfare at the moment but like i said - rich people stupid deep pockets. I mean how much was a Concorde ticket anyway?

The big point-to-point transport thing was a key feature of Musk's 2017 IAC presentation.

Without LES it's hard to justify, safety-wise.

@tater -- to the space hotel idea:

You'd probably need to do them in individual cruises. Crew and cargo boards a BFR, heads to the station, preps everything. Then the passengers come up for the actual cruise. No day-night cycles, so you'd want artificial gravity in a spin-up/spin-down model, probably. After the "cruise", crew and passengers come back together.

Length of stay and number of passengers for a break-even profit margin will tell you how big it has to be, minimum, to be solvent.

 

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31 minutes ago, sevenperforce said:

The big point-to-point transport thing was a key feature of Musk's 2017 IAC presentation.

Without LES it's hard to justify, safety-wise.

This is why I think P2P is not anything that could realistically happen for a long, long time.

To take your family to Sydney on a rocket, the 30 minute travel time is awesome, but you want it as safe as it would be on a 777. A rocket flight is cool, but I have no desire to kill my kids for a cool rocket ride, lol. Nor does anyone else.

Point to point is SF for the foreseeable future unless the BFS can somehow function as a LES.

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23 minutes ago, tater said:

This is why I think P2P is not anything that could realistically happen for a long, long time.

To take your family to Sydney on a rocket, the 30 minute travel time is awesome, but you want it as safe as it would be on a 777. A rocket flight is cool, but I have no desire to kill my kids for a cool rocket ride, lol. Nor does anyone else.

Point to point is SF for the foreseeable future unless the BFS can somehow function as a LES.

Also:

 

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24 minutes ago, tater said:

This is why I think P2P is not anything that could realistically happen for a long, long time.

To take your family to Sydney on a rocket, the 30 minute travel time is awesome, but you want it as safe as it would be on a 777. A rocket flight is cool, but I have no desire to kill my kids for a cool rocket ride, lol. Nor does anyone else.

Point to point is SF for the foreseeable future unless the BFS can somehow function as a LES.

And the BFS cannot function as its own LES, after all, particularly on landing.

I still think that a BFS with a cluster of maybe 9-12 SL Raptors could do virtually all P2P routes as a single stage. But, at minimum, you'd want a breakaway cabin with solids and chutes. For landing if nothing else.

For the space hotel concept, you have to keep in mind that from a market perspective, you're competing on a cost-per-night basis. If you need to make more money while still remaining competitive, you can make the cruises longer. But then you decrease the number of potential customers. Same with accommodation size; you have to make regular flights so you can't afford to do 1000 passengers on the first flight or you'll eat up your whole market.

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34 minutes ago, tater said:

This is why I think P2P is not anything that could realistically happen for a long, long time.

To take your family to Sydney on a rocket, the 30 minute travel time is awesome, but you want it as safe as it would be on a 777. A rocket flight is cool, but I have no desire to kill my kids for a cool rocket ride, lol. Nor does anyone else.

Point to point is SF for the foreseeable future unless the BFS can somehow function as a LES.

You're forgetting cargo. :wink: I think that's where P2P is first going to be adopted. There's no shortage of demand out there when some things absolutely positively have to be there yesterday (literally, if shipping from Sydney to LA), no matter the cost. If the cost is also competitive, well...

I think here is where the reliability will be able to be demonstrated before moving to passenger travel well down the road.

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28 minutes ago, CatastrophicFailure said:

You're forgetting cargo. :wink: I think that's where P2P is first going to be adopted. There's no shortage of demand out there when some things absolutely positively have to be there yesterday (literally, if shipping from Sydney to LA), no matter the cost. If the cost is also competitive, well...

I considered that a while back. What?

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21 minutes ago, sevenperforce said:

I meant what cargoes?

Things that currently go via express airfreight and such. Also, things too big and heavy to fly, that right now have to go by ship (30 days min). 

Example my lovely wife just gave me is a CT machine. (She does traffic analysis in the industry). Too bulky to fit on a plane, plus it’s got big magnets and such that don’t play well with airplane instruments (presumably a radiation-hardened spacecraft could tolerate such).

Also, airplane parts themselves. If an airline needs a new engine from across the ocean, those 10 or 12 hours of air cargo travel time are extra lost revenue.

Not a huge market perhaps, at the moment, but it’s there. How big depends on the price. 

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Well, if the wrong part breaks at the factory I work at, it can shut the whole shop down until it is replaced. Some parts we have to order from Germany to BC. Super-rush will get it to us around noon the next day; in the meantime the shop isn't making money. While it may be overkill to use BFS to P2P-ship a part that fits in a grocery tote, it could conceivably save us several hours of downtime, depending how long it takes to get it on and off the BFS, what the flight schedule is, etc.. It also depends, of course, on how much more it costs compared to regular next-day service. But we don't have any parts that couldn't go on a plane, either. I can't imagine having to replace an entire curing chamber (autoclave) and we have two of those anyways. But it would certainly slow the max possible production if one broke.

Edited by StrandedonEarth

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Another significant barrier for point-to-point rocket transportation is going to be all-weather capability, serviceability, and reliability.

It doesn't matter how quickly the vehicle travels, it's how quickly the cargo itself travels. If it takes a day to load, fuel, roll it out to the pad, and launch, well guess what? The subsonic 747 is already unloading at the destination. While I suspect SpaceX might be able to devise loading procedures quick by rocketry standards, there's other issues:

Rockets are more sensitive to weather-induced delays than aircraft.

The current standards for payloads sent to space are much more strict than in the air industry: you need to make sure there's no outgassing, that it doesn't have any mechanical issues with rocketry (such as the "your protein cubes have now destroyed the entire rocket" scene from The Martian). Not impossible to solve, but right now rocketry benefits from payloads being produced by people familiar with aerospace, people who know how to avoid outgassing and mechanical issues.

In other ways, they're less strict: payloads put an an aircraft probably are never pulling more than 1.5G of acc

There are a huge number of airports currently existing: spaceports would have to be built from scratch.

 

Overall, I suspect rocketry has a long way to go before it can compete for point-to-point service with the air industry. It'll be a tough bar to clear, against an industry with proven service on the order of about 24 hours to anywhere in the world. In this arena, a HTHL hypersonic vehicle might make more sense, so long as it can still land on many airfields. The best way I could think of to shoehorn that onto the BFR design would be to replace the upper stage with something with conventional landing gear and aerodynamic surfaces: the first stage would retain VTVL and RTLS, while the upper stage would need HTHL capabilities.

For fueling such a design: either you'd be limited to airports equipped with LOX compressors and methane stores, or bang your head against the wall of designing a high-performance engine that runs on the evil rocket-destroying JP-1 jet fuel, plus onboard LOX compressors.

Edited by Starman4308

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I don't see cargo as being much of a thing, many of the regulatory issues of crew vehicles...

the only outfit interested in cargo might be the military, and then by "cargo" I mean things like spy telescopes that launch, and by the time anyone figures out the orbit, the pics are already taken.

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7 hours ago, tater said:

This is why I think P2P is not anything that could realistically happen for a long, long time.

To take your family to Sydney on a rocket, the 30 minute travel time is awesome, but you want it as safe as it would be on a 777. A rocket flight is cool, but I have no desire to kill my kids for a cool rocket ride, lol. Nor does anyone else.

Point to point is SF for the foreseeable future unless the BFS can somehow function as a LES.

Well, baring in mind I'm Austrialian, there is no demand for this in the southern hemisphere. So no Sydney trip for you.

 

Now, I do not know how well travelled you are, but I will tell you that two cultures I know of where the superrich would use this at the risk of thier lives.

1) Chinese. For the rich it is a matter of face to spend too much money. If anyone they knew had done it and they hadn't it would be embarrasing. Perhaps I'm not explaining this well, but they would do it.

2) Emirates. Without being too specific, there are a group of very rich young males there who regularly do things like 300kph in their Ferrari's and porches. They have the money, they would do this regardless of risk.

So the question then becomes, how much is the sue and be sued world of today different from early aviation (when again, the rich used the dangerous new planes). Can you make a profit after insurance when you lose 1 in 10000, or 1 in 1000, or 1 in 100??

(BTW, If you paid, I would take a 1% chance of catastrophic death - not for suborbit maybe, but for orbit)

 

EDIT: I don't mean to single out ANY cultures. These two are within my personal experience and examples of different cultures from, well, America but lets say westerners.

Edited by Antstar

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I think there is a market, with a size that scales inverse to the cost and the risk.

Low cost and low risk is a vast market. Increased cost and risk lowers the market. Where the balance point lives is another issue. P2P is different, as it would also require high regulatory hurdles---supersonic landings, ballistic overflights, etc, would be... non-trivial.

Still, space tourism, unlike any other possible human spaceflight suggestion could actually make money. I used to think it was silly, but what else is there? In the 1950s and 60s, the idea of a von Braun S-1, with hundreds of crew seemed reasonable, because you need workers. Heck, you probably needed astrogators with punch cards and slide rules to work out the trajectories to the Moon base, lol. People are less needed now, and will only become even more superfluous for getting any work done.

Tourism is the killer app.

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5 hours ago, Starman4308 said:

Another significant barrier for point-to-point rocket transportation is going to be all-weather capability, serviceability, and reliability.

It doesn't matter how quickly the vehicle travels, it's how quickly the cargo itself travels. If it takes a day to load, fuel, roll it out to the pad, and launch, well guess what? The subsonic 747 is already unloading at the destination. While I suspect SpaceX might be able to devise loading procedures quick by rocketry standards, there's other issues:

There's a similar competition going on with airplanes and intercity trains. P2P BFR is particularly egregious because it's going to be launched from and to locations even more far-flung than airports.

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P2P BFR would still have the range of a 787/A350 at best. (more is obviously idiotic - you have a circle, just go the other way).

I say that a 787/A350 combi can do better than P2P BFR still.

Not to mention there has been no rocket launches during a storm.

Edited by YNM

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2 hours ago, YNM said:

P2P BFR would still have the range of a 787/A350 at best. (more is obviously idiotic - you have a circle, just go the other way).

I say that a 787/A350 combi can do better than P2P BFR still.

Not to mention there has been no rocket launches during a storm.

There's one more thing. Well granted, on a long distance flight, it doesn't really matter but still, it is an inconvenience: You have to get to and from the point where your BFR flight takes off from and lands. I mean given how loud an F9 is, I imagine that the BFR is still a bit louder. You won't have that landing near any populated area (well not only from noise considerations, range safety as well, I guess). And I am not even taking about the effects of NIMBY-ism. So lets figure there is one place in Europe, three in the US, maybe four in Asia, one in the Gulf region and one in Australia. That still means that you first of all have to travel to whichever Airport is close to the launch site, then travel to the launchsite, have your 30min flight to wherever, and then travel to the nearest airport to fly to your ultimate destination. Whereas now you maybe have a feeder flight and then can relax on board your long distance flight. Granted it takes a bit longer, but I would guess with all the to and fro involving the BFR, your grand total travel time will not be that much shorter. No way that thing is landing anywhere near any city...

BTW, if compared to regular airline travel, whats the CO2 footprint of a BFR taking off and landing? Also a consideration to take into account...

Edited by StarStreak2109

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50 minutes ago, StarStreak2109 said:

...  whats the CO2 footprint of a BFR taking off and landing? ....

Outch.

Bad, very bad. Like 3 magnitudes higher than a B747 or A380 ? But there is no reliable data on bfr yet, could be 2.9 magnitudes ;-)

 

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6 minutes ago, Green Baron said:

Outch.

Bad, very bad. Like 3 magnitudes higher than a B747 or A380 ? But there is no reliable data on bfr yet, could be 2.9 magnitudes ;-)

 

Then why use it on Earth P2P in the first place?!?

https://translate.google.de/translate?hl=de&sl=de&tl=en&u=http%3A%2F%2Fwww.spiegel.de%2Fwissenschaft%2Fnatur%2Fklimawandel-so-lassen-flugreisen-die-arktis-schmelzen-a-1119451.html

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@StarStreak2109, stop making me ashamed of not elucidating enough on my own points.

5 hours ago, DDE said:

There's a similar competition going on with airplanes and intercity trains. P2P BFR is particularly egregious because it's going to be launched from and to locations even more far-flung than airports.

:wink:

29 minutes ago, StarStreak2109 said:

Then why use it on Earth P2P in the first place?!?

Agitprop. Never forget that Musk is driving a hype train; I'm not sure what SpaceX would have been without it.

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