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Gwynne Shotwell: SpaceX's Plan to Fly You Across the Globe in 30 Minutes [video]

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Re: Gwynne Shotwell: SpaceX's Plan to Fly You Across the Globe in 30 Minutes [video]

#21

Post by bluGill »

cthulhujr wrote: post #2

>This is the only time I've out-visioned Elon ... I want to meet other people in other solar systems. You're not out-visioning Elon; it's a petty attempt at one-upmanship. It just doesn't seem genuine. I want to meet people in other Superclusters. Now she's been out-visioned!

You will never meet anyone from another solar system. Even if we assume such life exists (it might or might not - either is extraordinary), there is every reason to believe it is far away. It would be extraordinary again if that life is close enough to earth that the round trip of a radio transmission is within a human lifetime. There are just a few hundred (I wasn't able to find an exact number) starts within 25 light years - 50 year round trip time for a radio signal. We know of hundreds of earth like planets, but only by a definition that includes mars which is pretty much dead.

Re: Gwynne Shotwell: SpaceX's Plan to Fly You Across the Globe in 30 Minutes [video]

#22

Post by Rebelgecko »

Semirhage wrote: post #5

What would be the environmental impact of ubiquitous rocket launches for business travel?

Most people replies are focusing on carbon footprint, but it might also be worth considering noise (e.g. how does the sound of a rocket launching off the coast of California affect whales?) and any atmospheric perturbations caused by the rocket. Launches damage the ionosphere, which hasn't been an issue in the past because as far as we know the damage doesn't have a huge impact, and the ionosphere usually is back to normal within a few hours (or even less depending on trajectory and some other factors). If launches are happening every hour in the same area, that might cause some problems with things like radios.

Re: Gwynne Shotwell: SpaceX's Plan to Fly You Across the Globe in 30 Minutes [video]

#23

Post by aphextron »

Rocket based travel will never ever ever happen on a widespread scale simply because of the G forces involved. Passengers on an airliner will begin feeling uncomfortable at around 1.2 G's and > 20 degrees of bank angle. The thought of subjecting regular paying passengers to 3+ G's and a full 360 degrees of pitch/roll is absurd. It could definitely be a niche thing for people that are physically fit, but this just isn't the way to go for high speed transportation. More traditional airframes and scramjets are far more likely to make hypersonic travel a reality.

Re: Gwynne Shotwell: SpaceX's Plan to Fly You Across the Globe in 30 Minutes [video]

#24

Post by sandworm101 »

larrydag wrote: post #18

As a business model I think SpaceX should be a manufacturer and not in the transportation business akin to Boeing or Airbus. There is a ton of logistics involved in transporting people globally. Of course there is the safety issues as well.

>> safety issues as well.

And vomit. 4+G on launch. Freefall during cruise. 5+ G on reentry. Give me the first class ticket on a BA flight any day.

Re: Gwynne Shotwell: SpaceX's Plan to Fly You Across the Globe in 30 Minutes [video]

#26

Post by jerf »

Rebelgecko wrote: post #22
Semirhage wrote: post #5

What would be the environmental impact of ubiquitous rocket launches for business travel?

Most people replies are focusing on carbon footprint, but it might also be worth considering noise (e.g. how does the sound of a rocket launching off the coast of California affect whales?) and any atmospheric perturbations caused by the rocket. Launches damage the ionosphere, which hasn't been an issue in the past because as far as we know the damage doesn't have a huge impact, and the ionosphere usually is back to…

Does it damage the ionosphere? According to what definition of "damage"?

I honestly don't know, so if someone can explain how it really is damage, please do so by all means. But despite some popular suppositions to the contrary, "affects" != "damage". I know it affects it, probably from the same article from a week or so back as you, but that doesn't mean it's "damaged".

Re: Gwynne Shotwell: SpaceX's Plan to Fly You Across the Globe in 30 Minutes [video]

#27

Post by ceejayoz »

aphextron wrote: post #23

Rocket based travel will never ever ever happen on a widespread scale simply because of the G forces involved. Passengers on an airliner will begin feeling uncomfortable at around 1.2 G's and > 20 degrees of bank angle. The thought of subjecting regular paying passengers to 3+ G's and a full 360 degrees of pitch/roll is absurd. It could definitely be a niche thing for people that are physically fit, but this just isn…

If John Glenn could do a Shuttle flight at 77, I suspect you're overstating the difficulties here. People voluntarily subject themselves to 3+ Gs and 360 degrees pitch/roll at amusement parks daily, with fairly minimal levels of physical fitness being required.

Re: Gwynne Shotwell: SpaceX's Plan to Fly You Across the Globe in 30 Minutes [video]

#28

Post by btcindivist »

Retric wrote: post #16
btcindivist wrote: post #7

Earlier quoted context omitted.

Depends on how many. Flying airplanes is around 1-2% of our total CO2 footprint. Of course, for an individual, doing 1 intercontinental flight with a full plane is equivalent to months if not a year of driving a car to work every day, but in total, not many people fly. Depending on the efficiency of the rocket and the reduced number of people doing this, the numbers shouldn't be that much higher.

That's not really the case. Per passenger mile commercial aircraft get ~70MPG with longer flights tending to have better fuel economy. The trend is really interesting: http://www.slate.com/content/dam/slate/articles/business/the... So, they are actually very efficient transportation for long trips. Absolute worst case flying around the world is 24,901 mi which uses the same fuel per person as a 35 MPG car commuting 2…

What is not the case? 1-2% of total CO2 footprint? That flying a full plane is equivalent to months if not a year of driving a nontrivial distance every day?

I'm not saying cars are more efficient. It's just that the distance travelled is huge when one uses an airplane.

Re: Gwynne Shotwell: SpaceX's Plan to Fly You Across the Globe in 30 Minutes [video]

#29

Post by ceejayoz »

bmcusick wrote: post #14

The main thing I'm thinking of is noise pollution. You think living near an airport is loud? I cannot even imagine what living near a BFR spaceport would be like. For coastal cities maybe it would be worth it to build a landing pad on an ocean platform some miles out to sea, but what about for cities like Atlanta or Beijing? There's nowhere around them to build that isn't already a suburb.

I'd expect a city like Atlanta to be served by an off-shore landing zone, with high speed rail (hyperloop!) as the connection.

Re: Gwynne Shotwell: SpaceX's Plan to Fly You Across the Globe in 30 Minutes [video]

#30

Post by CarVac »

Retric wrote: post #16
btcindivist wrote: post #7

Earlier quoted context omitted.

Depends on how many. Flying airplanes is around 1-2% of our total CO2 footprint. Of course, for an individual, doing 1 intercontinental flight with a full plane is equivalent to months if not a year of driving a car to work every day, but in total, not many people fly. Depending on the efficiency of the rocket and the reduced number of people doing this, the numbers shouldn't be that much higher.

That's not really the case. Per passenger mile commercial aircraft get ~70MPG with longer flights tending to have better fuel economy. The trend is really interesting: http://www.slate.com/content/dam/slate/articles/business/the... So, they are actually very efficient transportation for long trips. Absolute worst case flying around the world is 24,901 mi which uses the same fuel per person as a 35 MPG car commuting 2…

Longer flights have better fuel economy only in short range regimes where the BFR is definitely not a consideration.

https://commons.m.wikimedia.org/wiki/File:777-224_fuel_burn-...

Fuel economy improves at first due to reduced overhead of taxiing, takeoff, and ascent, but as you go farther the fuel consumption increases due to the need to actually carry the fuel.

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