Author Topic: SpaceX suborbital shuttle - Anywhere on Earth in 25 minutes?  (Read 22099 times)

Offline Ben the Space Brit

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Well, I turned on my compute this morning to be confronted with a surprise in my YouTube recommended videos! Check this out!



Yes, you saw  that right. SpaceX are proposing to use BFR and a crew vehicle derived from ITS as a city-to-city suborbital passenger shuttle! So, the question arising is this: Is this the 'killer app' that will turn ITS from a pipe dream into a real consumer product? What does everyone think?


[edit]
Typo corrected
« Last Edit: 09/29/2017 06:35 AM by Ben the Space Brit »
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Offline DreamyPickle

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I'm not buying it, not without major changes. I bet we'll see a major updates to this.

Do they really need the full-sized booster for point-to-point travel? That thing is huge and operating it from a floating platform would be a major effort. Also I couldn't hope but notice the pad crane is the same one from IAC 2016 and still not very realistic.

Suborbital point-to-point travel would make a lot more sense with a dedicated single stage-vehicle.

Offline BroncoBill

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Rockets bigger than Apollo launching, and landing at night, in the vicinity of major cities, makes Concorde's sonic boom issue seem trivial .....

Online MikeAtkinson

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Rockets bigger than Apollo launching, and landing at night, in the vicinity of major cities, makes Concorde's sonic boom issue seem trivial .....

Landing out at sea. Sonic boom footprint small and should be (mostly?) over water.

Offline Tonioroffo

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Won't ITAR cause issues for this? 

Offline tobi453

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CO2 emissions anyone?

Musk believes in global warming and now he is proposing something that will emit ~10 times more CO2 compared to a normal plane.


Offline biosehnsucht

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Elon mentioned using Sabatier + solar to manufacture CH4 and O2 from atmospheric CO2 and water.. So by then he'll just be redistributing it (with some of it going off-planet).

Offline meekGee

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You don't know how close to the city it lands.  I'd guess 20 miles off shore, at least - and no overflight.

An SSTO wouldn't be practical.  Rockets stage for a reason, and this is practically a fully orbital launch.

But the boosters remain in their home ports, and can launch ships more often.

IF the fuel load is $1M, this can work, both for people and for fast cargo.
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Online MikeAtkinson

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I'm not buying it, not without major changes. I bet we'll see a major updates to this.

Do they really need the full-sized booster for point-to-point travel? That thing is huge and operating it from a floating platform would be a major effort. Also I couldn't hope but notice the pad crane is the same one from IAC 2016 and still not very realistic.

Suborbital point-to-point travel would make a lot more sense with a dedicated single stage-vehicle.

Almost certainly will have major updates, currently is not optimised for point to point, booster is too big, though I think that single stage would not be efficient enough on the longer routes.

Floating platform is probably cheap compared to a major airport, the can reuse the same design, so unit cost reduced. Problem is that they need one per destination, so creating a network can be expensive.

Online MikeAtkinson

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CO2 emissions anyone?

Musk believes in global warming and now he is proposing something that will emit ~10 times more CO2 compared to a normal plane.

Only about the same as a plane for the same route. Methane is much easier to reusably manufacture than aviation fuel, so potentially could be C02 neutral.

Offline Jarnis

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Noise issues alone will probably make this a bad idea. Look at the mess of paperwork because of Seals at Vandenberg with just a teeny F9 booster landing...

Offline Ben the Space Brit

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Do they really need the full-sized booster for point-to-point travel?

That depends on the launch payload. The payload fraction on the suborbital shuttle may be much higher than you could expect on any orbital spacecraft. If you only carry contingency and landing prop on the shuttle, you're carrying far more revenue-generating passengers and cargo per flight.
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Offline tobi453

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CO2 emissions anyone?

Musk believes in global warming and now he is proposing something that will emit ~10 times more CO2 compared to a normal plane.

Only about the same as a plane for the same route.


Big no. This system goes near orbital velocity. This takes a lot more energy than a simple plane. Just look at the mass: 500 tonnes for an aircraft compared to 5000 tonnes for this system.

Online Pipcard

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Won't ITAR cause issues for this?
I was thinking of that when the destination shown in the video was China...

Online MikeAtkinson

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CO2 emissions anyone?

Musk believes in global warming and now he is proposing something that will emit ~10 times more CO2 compared to a normal plane.

Only about the same as a plane for the same route.


Big no. This system goes near orbital velocity. This takes a lot more energy than a simple plane. Just look at the mass: 500 tonnes for an aircraft compared to 5000 tonnes for this system.

You forget that most of that mass is O2 and methane has lower carbon content than aviation fuel (particularly when full account is taken of fuel manufacture), probably more passengers. the booster need not be fully fueled and there are a few other optimisations that can be made for point-to-point.

Offline Patchouli

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BFR being used in this manner reminds me of a similar system proposed by Philip Bono during the 1960s.
http://www.astronautix.com/p/pegasusvtovl.html
« Last Edit: 09/29/2017 07:47 AM by Patchouli »

Online calapine

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It's the most minute of the details, but I think typical to the Musk approach:

The video says "Paris to New York 30 minutes"

Where in (near) Paris would he launch a BFR-sized rocket? CNES must feel like idots shipping Ariane to Kourou all the years when they could just lift-off from Paris-Orly Terminal 1.  :o

Offline darkenfast

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While I don't think that there's that much of a market to justify multiple launch/landing sites, I do think that there is a tourist market for this.  Think about it: why would you want to spend $100K plus to spend a few minutes on a BO or Virgin Galactic vehicle, just breaking the Karman Line (or not, in the case of Virgin), when for a much smaller amount, you can spend between 30 to 60 minutes on a point to point  flight to a tourist destination on the other side of the globe, and with an apogee hundreds of kilometers higher?  If the interior space of the BFR can be reconfigured (as some commercial aircraft can be today), then this is another use for the vehicles between synods.

I'm not sure about the city-to-city routine flights as shown on the video, but I think there is enough market for the tourist aspect.  Or heck, why not a 24-hour "Day-in-Space" flight?

Offline Ben the Space Brit

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It's the most minute of the details, but I think typical to the Musk approach:

The video says "Paris to New York 30 minutes"

Where in (near) Paris would he launch a BFR-sized rocket? CNES must feel like idots shipping Ariane to Kourou all the years when they could just lift-off from Paris-Orly Terminal 1.  :o

It can be a few tens of miles outside of Paris (like many modern large commercial airports). Once you remove the need for a safe location to dispose of spent booster stages, the space requirements and debris hazard from a rocket launch site drops down precipitately. There is still a danger from anomalies but this is equally true for those living in the farmland around CDG.
"Oops! I left the silly thing in reverse!" - Duck Dodgers

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The time for words has passed; The time has come to put up or shut up!
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Online Nibb31

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I'm pretty sure that having suborbital hypersonic projectiles heading towards major cities is going to make some people nervous.

How far is far enough for the noise not to become an issue ? At the same time, you need to be close enough to a city for the transit time to make it worthwhile. Currently, you typically spend 3 hours to get to an airport, check in, go through TSA, customs, and board, and then 1 hour to collect your luggage and leave the airport on arrival. There is more to gain by streamiling those processes than developing P2P suborbital. Putting the landing site a hundred kilometers from your destination only increases the total transit time.

There is also quite some concern about manoeuverability. Once you're on a 30 minute parabolic trajectory, you are pretty much committed to landing at your destination. You don't have much time to divert if there is an incident at the destination, and you certainly don't have go around capability.

And doing P2P flights with the BFR design doesn't make much sense: you don't need the vacuum raptors or the header tanks, so it really needs a different vehicle. And once you are designing a new vehicle, you might as well optimize the pax capacity for the market, which probably means a smaller vehicle altogether.
« Last Edit: 09/29/2017 08:59 AM by Nibb31 »

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