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SpaceX BFR [video]

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Re: SpaceX BFR [video]

#221

Post by Florin_Andrei »

drinchev wrote: post #91

I think if we measure the travel time from door to door the benefits of the fast rocket shrink in a relation to where is located. With airplanes this is solved, by the big infrastructure ( cities sometimes have even 2-3 airports ). Where I live ( Berlin ) with a flight to NYC would look like : 1. City center -> TXL - 20m 2. Check-in / security - 30m ( no joke, the airport is small ) 3. Flight - 9h 15m 4. Check-out /…

One thing you're missing:

For a very high profile requirement - say, some kind of huge emergency - you could land the BFR anywhere there's a solid surface the size of a soccer field. Zero infrastructure required.

Getting it out of there again would be difficult, but you could have a team of experts and a whole lot of material resources literally drop down from the sky anywhere on Earth in a matter of hours. Most of that duration would be spent loading the human and material cargo into the rocket.

We have no way of doing that currently.

P.S.: And if the emergency is big enough, you could drop the whole thing into the ocean near the shore and just jettison the passengers and cargo shortly before impact.

Rapid intervention anywhere on Earth. Literally.

Re: SpaceX BFR [video]

#222

Post by planteen »

OrwellianChild wrote: post #194
idlewords wrote: post #121

Earlier quoted context omitted.

They do, but the crux of every Musk fantasy is a radical drop in the cost of these things, a promise he has never delivered on.

Tesla Roof is cheaper than many traditional roofing materials and provides solar. See the chart here. [1] Air Force launches with SpaceX are less than half the price of ULA launches. [2] Can you clarify how you believe Musk's companies haven't delivered? [1] https://www.bloomberg.com/news/articles/2017-05-10/tesla-s-s... [2] https://www.engadget.com/2017/06/16/us-air-force-spacex-ula-...

To be fair, you couldn't get a solar roof delivered in the next month like you could a traditional one.

From their site "Initial trial installations are complete and undergoing evaluation, customer installations are about to start and will ramp up through 2017."

https://www.tesla.com/solarroof

Seems like it needs an update, 2017 is almost over...

Re: SpaceX BFR [video]

#224

Post by Florin_Andrei »

thesash wrote: post #151

There are three things that would factor into my decision about whether to strap myself to a rocket rather than fly in a plane: time, cost, and safety. Musk & SpaceX are talking a lot about time and cost, but safety is obviously a lot more important. Based on data I found on the internet (so it must be true!) the loss rate for rockets is 20k - 165k higher than the fatal crash rate for airplanes over the past 20 years…

> There are three things that would factor into my decision about whether to strap myself to a rocket rather than fly in a plane: time, cost, and safety.

It's a valid concern, but it's only a matter of time before each new technology is perfected and made safe.

The exact same debates took place when Stephenson built his locomotive.

Re: SpaceX BFR [video]

#225

Post by [deleted] »

drinchev wrote: post #91

I think if we measure the travel time from door to door the benefits of the fast rocket shrink in a relation to where is located. With airplanes this is solved, by the big infrastructure ( cities sometimes have even 2-3 airports ). Where I live ( Berlin ) with a flight to NYC would look like : 1. City center -> TXL - 20m 2. Check-in / security - 30m ( no joke, the airport is small ) 3. Flight - 9h 15m 4. Check-out /…

[deleted]

Re: SpaceX BFR [video]

#226

Post by simplicio »

1053r wrote: post #216
simplicio wrote: post #202

Earlier quoted context omitted.

The problem is that to increase flight rates by 5 orders of magnitude, you need demand to increase by that much. And people are unlikely to demand rocket flights until after they're as safe as plane flights. Early passenger planes were pretty dangerous to, but they got around the above problem by a) being much faster than trains, making the risk worth it, b) having clear military applications, the military being less…

You answered your own question: military applications. The US Armed Forces would pay a LOT of money to move 100+ tons of personnel and materiel anywhere on earth with a flat landing spot in under 60 minutes. You could have tanks on the ground that were fully operational in under 3 hours (probably half that if they left the BFR packed and fueled for takeoff at all times), or a disaster recovery base set up within 24 h…

Maybe, though the military has studied similar ideas before and nothing has ever come from it, so I'm sceptical they're going to throw the kind of funding at it that would be required here. As a general concern, actual travel time doesn't usually seem to be the main determinant of how fast military forces can be deployed.

But who knows. The idea of a big capsule coming down in a war zone and a bunch of tanks and marines rolling out certainly seems pretty cool, and I'm sure Musk and his lobbyists will at least try and convince the DoD that its something worth throwing a lot of $$ at.

Re: SpaceX BFR [video]

#229

Post by cheeko1234 »

grinich wrote: post #176
simonh wrote: post #138

Earlier quoted context omitted.

It’s a really good question. Supersonic jets were always heavily constrained due to noise pollution issues with the sonic boom. They weren’t allowed to fly over land at supersonic speeds, relegating them to trans-oceanic routes. Now yes this system will have such problems on launch, but as they go pretty much straight up out of the atmosphere compared to a jet, the vast majority of the journey is in space where that’…

After the Concord was built, NASA did some research into reducing sonic booms (the Shaped Sonic Boom Experiment) which showed you could modify the fuselage to reduce the noise shock by about 30%. This would have brought the Concord below the acceptable noise threshold. Unfortunately it was never built-out commercially and we now have legislation banning supersonic flight over land. https://en.wikipedia.org/wiki/Shape…

That's the goal of the current quesst program.

https://www.nasa.gov/press-release/nasa-begins-work-to-build...

Re: SpaceX BFR [video]

#230

Post by thinkcontext »

simplicio wrote: post #202
Robotbeat wrote: post #153

Earlier quoted context omitted.

Loss rate for space launches is largely due to the fact that the systems are essentially munitions (i.e. expendable, single-use) and flight rates are very low. Rocket failures for crewed rocket launches are extremely rare, occurring once every couple decades. It's hard to improve on that because low flight rates make data very hard to come by. Airplanes fail much more often in absolute terms, giving you a lot more da…

The problem is that to increase flight rates by 5 orders of magnitude, you need demand to increase by that much. And people are unlikely to demand rocket flights until after they're as safe as plane flights. Early passenger planes were pretty dangerous to, but they got around the above problem by a) being much faster than trains, making the risk worth it, b) having clear military applications, the military being less…

They can fly cargo. FedEx would definitely be able to market such a service.
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