Author Topic: How BFR Earth-to-Earth Might Actually Get Started  (Read 104083 times)

Offline su27k

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #440 on: 08/14/2018 01:10 am »
Luck is being prepared and then being in the right place.

It's not pure luck that COTS started during SpaceX's early years, SpaceX sued NASA for its sole source contract to Kistler, that's one of the reason COTS got started. Unlike Beal, Musk will fight tooth and nail for what he wants, he won't roll over just based on some words from a NASA administrator.

Offline TripleSeven

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #441 on: 08/14/2018 06:03 am »
Luck is being prepared and then being in the right place. Was Musk lucky? Ssure. But betting against him, as 777 does, here and in other threads? bad idea.

And getting back to "time" being what people are paying for, today the longest airline routes take 17 hours, so in order for a BFR point-to-point service to work there needs to be a large enough population of well off people that value time more than money.
Many consultants bill at 200, 300, even 500 USD an hour. Save 16 hours each way and you may be able to bill for a good part of that. That might, or might not, form part of the market.

you are spot on with luck...random chance operating in ones favor

as for beating against Musk...no not really ...I am just not caught up in the... oh what was the phrase about the stock market "irrational exuberance" Musk did make me money on his Tesla "going private" thing :) 

his approaching the Saudis bothers me


Offline TripleSeven

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #442 on: 08/14/2018 06:26 am »
Luck is being prepared and then being in the right place.

It's not pure luck that COTS started during SpaceX's early years, SpaceX sued NASA for its sole source contract to Kistler, that's one of the reason COTS got started. Unlike Beal, Musk will fight tooth and nail for what he wants, he won't roll over just based on some words from a NASA administrator.


it is pure luck and fate that COTS started during SpaceX early years...SpaceX involvement with it...is not pure luck, they worked at it...they had to have it...if they didnt get it they were in thehole money wise...but its "luck" it was going.


it is completely off topic but I would just say this about your statement on Andrew Beal.  Beal didnt roll over on anything....after spending some money and doing some development (they fired a large liquid engine) he looked at the "proposed market" and didnt see one.   Andy is above all a mathematician "poker" player and I think he approaches business like that...ie its a matter of the odds and chances  and what cards are being held by "others"  My  impression is that he figured he could build a rocket, make it fly and then have really no customers to make the money back.

in 1997 that was not in my view an unreasonable bet.  NASA was going to fly the shuttle forever, or some version of it; the USAF was pretty happy with its choices on the EELV and any effort had missed the Iridium etal depoyment window, in fact by 97 the mene, mene, tekel, upharsin of iridiums demise was already scratching out on the wall

As for fighting though, he keeps a certain lawyer and law firm fairly busy doing just that :) And he is known in Big D as a guy who will come at you fairly hard.    if you dont think he will fight for something he "needs to" you dont know Andy Beal.    Think JR. Ewing :)

« Last Edit: 08/14/2018 06:48 am by TripleSeven »

Offline meekGee

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #443 on: 08/14/2018 10:12 am »
TripleSeven, being skeptical is ok.

But when someone is skeptical of almost anything Musk/SpaceX, while at the same time exuberant about BO's prospects (or VGs) then it's "selective skepticism" and loses credibility.

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ABCD: Always Be Counting Down

« Last Edit: 08/14/2018 08:18 pm by meekGee »
ABCD - Always Be Counting Down

Offline Zed_Noir

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #444 on: 08/14/2018 07:52 pm »
Luck is being prepared and then being in the right place. Was Musk lucky? Ssure. But betting against him, as 777 does, here and in other threads? bad idea.

And getting back to "time" being what people are paying for, today the longest airline routes take 17 hours, so in order for a BFR point-to-point service to work there needs to be a large enough population of well off people that value time more than money.
Many consultants bill at 200, 300, even 500 USD an hour. Save 16 hours each way and you may be able to bill for a good part of that. That might, or might not, form part of the market.

you are spot on with luck...random chance operating in ones favor

as for beating against Musk...no not really ...I am just not caught up in the... oh what was the phrase about the stock market "irrational exuberance" Musk did make me money on his Tesla "going private" thing :) 

his approaching the Saudis bothers me

According to what I read online. It seems to me the Saudis approach Musk several time in the last 2 year. They wanted acquire some stocks from Tesla itself to diversified their investment portfolio. Instead Musk directed them to acquire from the market.

Of course Musk getting the opportunity to do a short squeeze on people shorting Tesla is just a happy coincidence.  ;)
« Last Edit: 08/16/2018 07:49 am by Zed_Noir »

Offline john smith 19

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #445 on: 08/14/2018 08:26 pm »
If the engines are no better than Merlins, or the structure is heavier than F9 percentage-wise, or the heatshield can only cope with 4km/s reentry, these do not make Mars particularly more expensive for the first few missions.
Excuse me? LEO to landing is about 8Km/sec. Surviving 4Km/sec means every BFR is a one way trip to Mars.
I find it incredible that somehow BO is assumed to have a superior to SpaceX orbital class product early next decade given that BO has zero experience launching anything orbital.  The kinetic energy difference from sub orbital to orbital is huge, so recovery of a suborbital vehicle is nowhere near the difficulty of recovering an orbital vehicle.
True, which is why F9 booster recovery is a (fairly) routine process at SX while F9 US recovery has been on hold since 2014.
Quote from: philw1776
For SpaceX to recover and reuse a 2nd stage of an orbital vehicle is not a huge step for them given their Dragon and F9 booster experience. 
No, it really is. The Dragon is (in passenger terms) Shuttle sized. BFS is sized (wheather it has that capacity on first launch) is close to 17x bigger.
Quote from: philw1776
BFS LEO isn't doing anything not done by the 1970s design Space Shuttle except powered landing (already done routinely by SpaceX) and most importantly economics.  Remains to be seen how much better the economics prove to be.

You missed the upper stage engine ignition.

it is completely off topic but I would just say this about your statement on Andrew Beal.  Beal didnt roll over on anything....after spending some money and doing some development (they fired a large liquid engine) he looked at the "proposed market" and didnt see one.   Andy is above all a mathematician "poker" player and I think he approaches business like that...ie its a matter of the odds and chances  and what cards are being held by "others"  My  impression is that he figured he could build a rocket, make it fly and then have really no customers to make the money back.
AS well as operating (at the time) the biggest filament winder in the world.

These puppies are built to order and the have long lead times. 

He doesn't sound like someone you want to get on the wrong side of.
« Last Edit: 08/15/2018 06:53 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline john smith 19

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #446 on: 08/14/2018 08:49 pm »
There's been lots of interesting points made on this thread but perhaps we could return to its title?

I will simply presume that BRF can be made to work well enough to meet the needed specs for a "ballistic transport."

SX are known for aiming to start revenue generation fairly quickly. This suggests they would seek sites within the entire US which have a (potentially) high number of passengers, while side stepping ITAR issues

I though NYC/LA/Hawaii/ and Washington DC. Alaska is suitably far away from other parts of the US but how many people actually go there?

Can anyone suggest any better options? How many sites do people think SX would need (two is obviously the minimum, or is it? Would a triangle be better?

Or do people think the best way forward is some kind of DoD transport contract to rack up flight hours with a customer who accepts things might not always go to plan but who has a lot of cargo to move? Obviously this is bit more tricky WRT ITAR. OTOH aren't overseas US bases US territory? So a flight would mean moving a BFR from one part of the US (in the US) to another part of the US (in a foreign country)?
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline speedevil

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #447 on: 08/14/2018 08:59 pm »
If the engines are no better than Merlins, or the structure is heavier than F9 percentage-wise, or the heatshield can only cope with 4km/s reentry, these do not make Mars particularly more expensive for the first few missions.
Excuse me? LEO to landing is about 8Km/sec. Surviving 4Km/sec means every BFR is a one way trip to Mars.
3km/s retroburn on earth, to enter at 4km/s. This uses about half the payload capacity. Being able to cope with a one-off entry is rather different.

If your vehicle cannot cope with 8km/s entry, you can land on Mars by going into a capture orbit using ~800m/s, then aerobrake down slowly to LMO - like mars global surveyor. This only requires your heatshield to be good to 4km/s or so. (this does not work for crewed landings on earth so well, due to the magnetic field and associated radiation belts.)

This costs around 50 tons of payload, or requires one to two extra refillings around earth escape velocity.

This would get you up to around 16 launches, not 7, for a BFS to Mars.

Returning from Mars would either require a more capable vehicle - or you end up around L2, and wait for pickup.

Operationally - the costs initially do not change much, as you are still going to have the same number of BFS on their way to Mars, for the same amount of time. The cost of launch goes from $30M to $80M - around half your vehicle cost, rising to perhaps 25% of the total cost of the mission launch. (Assuming $5M launches).

It would be a major pain if it's not worked out by (nominal) 2026.

Offline spacenut

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #448 on: 08/14/2018 09:06 pm »
I believe it will be a cargo transport first.  Probably for the military.  They have to get a lot of launches and landings before they transport passengers or troops to prove safety. 

I think they would have one facility at China, Japan, India, Middle East somewhere, Australia, somewhere in Europe.  Later other countries.  SpaceX, once they get BFR/BFS up and running may get these other countries to build the facilities to receive and launch these transport rockets. 

They still have to use it to get Constellation up and running, and make a trip to Mars or the Moon.  Transport of goods and people probably won't start until 10 years after that. 

Offline john smith 19

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #449 on: 08/15/2018 06:52 am »
I think they would have one facility at China, Japan, India, Middle East somewhere, Australia, somewhere in Europe.  Later other countries.  SpaceX, once they get BFR/BFS up and running may get these other countries to build the facilities to receive and launch these transport rockets. 
China, India, Middle East are all going to be very problematical for ITAR. That is also a lot of investment in infrastructure, given the comment that Vega's launch tower was described as "The Eiffel Tower..on wheels"
Quote from: spacenut
They still have to use it to get Constellation up and running, and make a trip to Mars or the Moon.  Transport of goods and people probably won't start until 10 years after that.
By "Constellation" I presume you mean Starlink. That has to be the first use case for BFR, constellation deployment.

IMHO BFR will go to the Moon if NASA pays for them.  In which case sure they'll go. OTOH either it takes a big payload hit and does not refuel on the Moon, or someone has to figure out ISRU using Lunar materials.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline speedevil

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #450 on: 08/15/2018 10:23 am »
IMHO BFR will go to the Moon if NASA pays for them.  In which case sure they'll go. OTOH either it takes a big payload hit and does not refuel on the Moon, or someone has to figure out ISRU using Lunar materials.
Going to the moon takes one full refuel in LEO, and you can drop 20 tons of material on the surface from rest 100m up and return. (or have a real close up view of the moon for a few dozen passengers).

The risk of this, in the context of a BFS where you are considering passenger service, is almost precisely the cost of seven launches.

If you have a landing site worked out, and have an extra BFS to orbit the moon, then for around eight launches you can pretty much take a third of a nominal passenger load (50 tons) to the moons suface and back.
ISRU is not required.
Lunar swingby flights are even cheaper, though these can only do a handful of people if unrefuelled, or a full load with a couple of refuellings.

Lunar tourism is almost a given, if P2P happens IMO.
It being reliable enough for P2P means that the cost of refuelling is simply the marginal cost of launching the flight, and no part of it is capital.

Lunar cargo is almost required to have some of it be able to be free, as you need to do extensive testing to get the statistics to be able to claim safety for passengers, and you're going to run out of things to launch.
At passenger transit prices, missions like 'grab 50 tons of moon rock for resale to the public' may be profitable - never mind any payment for deploying science missions.

Outline of BFR to moon, with no modifications or extra hardware required.
« Last Edit: 08/15/2018 10:34 am by speedevil »

Offline philw1776

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #451 on: 08/15/2018 04:25 pm »
I find it incredible that somehow BO is assumed to have a superior to SpaceX orbital class product early next decade given that BO has zero experience launching anything orbital.  The kinetic energy difference from sub orbital to orbital is huge, so recovery of a suborbital vehicle is nowhere near the difficulty of recovering an orbital vehicle.
True, which is why F9 booster recovery is a (fairly) routine process at SX while F9 US recovery has been on hold since 2014.
Quote from: philw1776
For SpaceX to recover and reuse a 2nd stage of an orbital vehicle is not a huge step for them given their Dragon and F9 booster experience. 
No, it really is. The Dragon is (in passenger terms) Shuttle sized. BFS is sized (wheather it has that capacity on first launch) is close to 17x bigger.
Quote from: philw1776
BFS LEO isn't doing anything not done by the 1970s design Space Shuttle except powered landing (already done routinely by SpaceX) and most importantly economics.  Remains to be seen how much better the economics prove to be.

You missed the upper stage engine ignition.


Remember that the context of my post where these were snipped from was relative to BO's future capabilities.

That said...
There were never executed "plans" that had the Shuttle carrying over 50 passengers.  By that bogus 17x passenger metric BFS is not much bigger.  A more rational engineering based comparison is the mass of the 1970 designed Shuttle to the 2020s designed BFS mass. 

US recovery for F9 makes zero economic sense since the payload delivered to orbit would be minimal.  Had SpaceX done a RUS, Raptor Upper Stage (not Rodents of Unusual Size) the extra payload capacity may have made stage 2 recovery marginally useful.  But as we all know the public position from SpaceX is that F9 is done and all speed ahead to BFR.  We'll see if this holds.

I didn't mention US ignition because it's not worth mentioning as I don't see upper stage ignition being a problem for anyone.


FULL SEND!!!!

Offline john smith 19

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #452 on: 08/16/2018 06:59 am »
That said...
There were never executed "plans" that had the Shuttle carrying over 50 passengers.  By that bogus 17x passenger metric BFS is not much bigger.  A more rational engineering based comparison is the mass of the 1970 designed Shuttle to the 2020s designed BFS mass. 
The correct comparison is not with the Shuttle orbiter, it's with the whole stack, including the SRB's and ET.
Which came to about 4 million lbs, or 1818 tonnes.
Quote from: philw1776
US recovery for F9 makes zero economic sense since the payload delivered to orbit would be minimal.  Had SpaceX done a RUS, Raptor Upper Stage (not Rodents of Unusual Size) the extra payload capacity may have made stage 2 recovery marginally useful.  But as we all know the public position from SpaceX is that F9 is done and all speed ahead to BFR.  We'll see if this holds.
Economic US reuse is indeed  a very hard problem, as SX have found out. But it's the only think that
has anywhere near the scale of the BFS and has to lose the full orbital amount of KE and PE.
Quote from: philw1776
I didn't mention US ignition because it's not worth mentioning as I don't see upper stage ignition being a problem for anyone.
Funny you should say that.
That's exactly the reason cited why SLS was re-designed (at considerable expense after NASA had chosen the original design, and both Boeing and LM had selected SSME as their 2nd stage engine).

Of course SSME is a very complicated Fuel Rich Stage Combustion cycle with a very complex start cycle that was only the 2nd SC designed in the US without any modern design tools and needing all 3 fuel rich combustion chambers to come up to pressure in the right sequence.

No doubt the Raptor, with it's Fuel rich preburner , Ox rich preburner and main combustion chamber will be much easier to start up with all those new design tools.

Since Raptor has been designed for Mars in principle "Attitude start" should have been designed in from day 1.

Has anyone any reports of any Raptor altitude start tests I might have missed?
« Last Edit: 08/16/2018 07:04 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline john smith 19

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #453 on: 08/16/2018 07:02 am »
If you have a landing site worked out, and have an extra BFS to orbit the moon, then for around eight launches you can pretty much take a third of a nominal passenger load (50 tons) to the moons suface and back.
ISRU is not required.
Lunar swingby flights are even cheaper, though these can only do a handful of people if unrefuelled, or a full load with a couple of refuellings.
It's an interesting (policy) question if an architecture without needing ISRU would get more or less support from NASA.

The upside would be that NASA could devote more budget to the actual Moon base and its core scientific mission.

The downside, less cutting edge surface engineering to do.

We might think that sounds like a pretty good way to go, but I think the NASA position is more complex.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline speedevil

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #454 on: 08/16/2018 10:35 am »
ISRU is not required.
It's an interesting (policy) question if an architecture without needing ISRU would get more or less support from NASA.

The upside would be that NASA could devote more budget to the actual Moon base and its core scientific mission.

The downside, less cutting edge surface engineering to do.

Cutting edge NASA mission architecture needs to be avoided for any commercial venture to make sense in the future where P2P is a reality.
If the space hotel that you're building costs $25M/ton to build, and $0.01M/ton to place on the moon, things have gone horribly, horribly wrong.

I don't see a place for NASA anywhere near mass passenger transport infrastructure, other than as a customer like any other.

Offline envy887

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #455 on: 08/16/2018 01:23 pm »
That said...
There were never executed "plans" that had the Shuttle carrying over 50 passengers.  By that bogus 17x passenger metric BFS is not much bigger.  A more rational engineering based comparison is the mass of the 1970 designed Shuttle to the 2020s designed BFS mass. 
The correct comparison is not with the Shuttle orbiter, it's with the whole stack, including the SRB's and ET.
Which came to about 4 million lbs, or 1818 tonnes.
Quote from: philw1776
US recovery for F9 makes zero economic sense since the payload delivered to orbit would be minimal.  Had SpaceX done a RUS, Raptor Upper Stage (not Rodents of Unusual Size) the extra payload capacity may have made stage 2 recovery marginally useful.  But as we all know the public position from SpaceX is that F9 is done and all speed ahead to BFR.  We'll see if this holds.
Economic US reuse is indeed  a very hard problem, as SX have found out. But it's the only think that
has anywhere near the scale of the BFS and has to lose the full orbital amount of KE and PE.
Quote from: philw1776
I didn't mention US ignition because it's not worth mentioning as I don't see upper stage ignition being a problem for anyone.
Funny you should say that.
That's exactly the reason cited why SLS was re-designed (at considerable expense after NASA had chosen the original design, and both Boeing and LM had selected SSME as their 2nd stage engine).

Of course SSME is a very complicated Fuel Rich Stage Combustion cycle with a very complex start cycle that was only the 2nd SC designed in the US without any modern design tools and needing all 3 fuel rich combustion chambers to come up to pressure in the right sequence.

No doubt the Raptor, with it's Fuel rich preburner , Ox rich preburner and main combustion chamber will be much easier to start up with all those new design tools.

Since Raptor has been designed for Mars in principle "Attitude start" should have been designed in from day 1.

Has anyone any reports of any Raptor altitude start tests I might have missed?

Starting an engine in free-fall is quite different than starting it on the ground or while under acceleration. However, it's not that difficult if included in the design from the beginning, which SSME was not.

Raptor has never been test fired in freefall. Neither was MVac before the F9 demo, nor any other air-start engine as far as I'm aware. Ground tests are sufficient.

Offline john smith 19

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #456 on: 08/16/2018 08:39 pm »
Cutting edge NASA mission architecture needs to be avoided for any commercial venture to make sense in the future where P2P is a reality.
If the space hotel that you're building costs $25M/ton to build, and $0.01M/ton to place on the moon, things have gone horribly, horribly wrong.
I agree totally.

but I'm pointing out that if NASA is the major customer for Lunar flights their "design competition" might penalize not having an ISRU system.

It makes no sense unless we're talking a long term Lunar outpost needing regular resupply.
Quote from: speedevil
I don't see a place for NASA anywhere near mass passenger transport infrastructure, other than as a customer like any other.
Again no argument here.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Online LMT

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #457 on: 08/27/2018 04:40 am »
you'd also want luxury flights, with 50, not 1000 people onboard, and going to a nice orbital or lunar resort.

1000 or 100?

Luxury tourism needn't limit flights to 50 passengers.  100 passengers can be ok, so long as the orbital destination is more spacious.  A SpaceX tail-docked Marsliner resort would have twice the volume of the transport, dividing tourists into accommodations for 2 x 50.  Luxury, yes?

Also it should be emphasized that a short-duration stay like the notional Marsliner 3-day package would be reasonable only in a partial-g resort.  In a low-g resort, many tourists would spend their brief stay fumbling, ricocheting, and being ill. 



In contrast, the Marsliner's partial g would be a stabilizing godsend for tourists.

When you think about it, it's rather interesting that SpaceX's current tail-dock config can be readily adapted to give comfortable partial-g tourism.  Coincidence or not, SpaceX settled on a system that's just big enough for use as the premier LEO resort - a system, moreover, that applies a bare minimum of complexity and reusable mass toward that potential purpose.
« Last Edit: 08/27/2018 04:50 am by LMT »

Offline mikelepage

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #458 on: 09/16/2018 11:22 am »
The preview pic for BFS apparently has 7 sea level raptors, and no vacuum raptors, but a skirt that is speculated to substitute for a vacuum nozzle - perhaps in combination with throttling down the outer 6 engines. This again puts fuel on the fire for BFS use as a single stage to orbit, which would greatly reduce the logistical challenges for P2P BFS transport around the Earth.

So much easier to see Earth to Earth happening if they donít need boosters at every launch location. They would only need to launch enough cargo BFSs for beyond LEO operations, while still getting a ton of experience operating the vehicle(s).

Offline su27k

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Re: How BFR Earth-to-Earth Might Actually Get Started
« Reply #459 on: 09/16/2018 11:37 am »
The preview pic for BFS apparently has 7 sea level raptors, and no vacuum raptors, but a skirt that is speculated to substitute for a vacuum nozzle - perhaps in combination with throttling down the outer 6 engines. This again puts fuel on the fire for BFS use as a single stage to orbit, which would greatly reduce the logistical challenges for P2P BFS transport around the Earth.

I hope this is true, but 7 Raptors is still not enough, the TWR at liftoff is ~1.02.
« Last Edit: 09/16/2018 11:38 am by su27k »

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