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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]

#101

Post by [deleted] »

soared wrote: post #34
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…

20 minutes of discomfort to save 12+ hours of flight time? Sounds worth it to me.

[deleted]

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

#102

Post by jryle70 »

Retric wrote: post #35
CarVac wrote: post #30

Earlier quoted context omitted.

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.

Aircraft choice plays a role here. Airlines tend to use more efficient aircraft for longer flights.

Airlines use longer range aircrafts for longer flights. That should be obvious, shouldn't it?

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

#103

Post by Rebelgecko »

jerf wrote: post #26
Rebelgecko wrote: post #22

Earlier quoted context omitted.

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".

I guess "damage" is a judgement call I'm not really qualified to make. Someone could probably make the argument that humanity can't "damage" a natural system because we're part of nature. When half the electrons disappear over a few thousand square kilometers, it's not inherently better or worse. It may annoy someone at Arecibo Observatory or a HAM radio operator or a GPS user, but maybe there's also some positive aspects of that temporary depletion.

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

#104

Post by FullMtlAlcoholc »

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…

You seem to underestimate how annoying modern air travel is, at least in America. One has to stand in at least 3 different lines (baggage, security, boarding) before getting on the plane. Whether in the terminal or on the aircraft, the seating feels like it was designed to be as uncomfortable as possible.

I imagine that there will be people willing to travel via rocket just because of the 3+ G's. And I'd take a 30 minute roller coaster ride over a 10 hr first class flight any time, all the time. Less time spent flying > comfort while flying. One immediate benefit is that one doesn't have to take a week or more off of work for intercontinental travel. Weekend jaunts to Pattaya or the Alps are possible when you aren't spending 20+ hours in transit.

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

#105

Post by Retric »

jryle70 wrote: post #102
Retric wrote: post #35

Earlier quoted context omitted.

Aircraft choice plays a role here. Airlines tend to use more efficient aircraft for longer flights.

Airlines use longer range aircrafts for longer flights. That should be obvious, shouldn't it?

Efficiency is one way to increase range. Wingtip devices can reduce drag by inhibiting vortex formation, however they increase weight so there is a minimum flight distance before they are a net gain. https://en.wikipedia.org/wiki/Wingtip_device

There is a tradeoff of needing carry more fuel over a portion of the flight, but the aircraft also spends a higher percentage of it's fuel on flying vs taxiing etc.

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