If you can read this, either the style sheet didn't load or you have an older browser that doesn't support style sheets. Try clearing your browser cache and refreshing the page.

•       •       •

666 clicks; posted to Geek » on 03 Oct 2017 at 10:20 PM (41 weeks ago)   |   Favorite    |   share:    more»

 Paginated (50/page) Single page, reversed Normal view Change images to links Show raw HTML
View Voting Results: Smartest and Funniest

Oldest | « | 1 | 2 | » | Newest | Show all

the_innkeeper: A Falcon 9 can carry 7 passengers, for an unknown number of flights. Let's assume 100, for now. Total of 700 passengers for \$60M.

I think that's one of the assumptions that needs to be changed. The Falcon 9 can carry 22 thousand kg to LEO, with a delta-v of about 9.2 km/s. But we're not going to orbit - these are sub-orbital flights. A sub-orbital trajectory at maximum range (halfway across the world) requires a delta-v of about 7.9 km/s, and an intercontinental flight (5500km) requires only a delta-v of 6.1 km/s. Let's split the difference and say 7 km/s is going to be average for these flights. That's a 23% reduction in delta-v. But since the rocket equation includes a natural log, the resulting increase in payload is around 3.5 times, or 77 thousand kg to an intercontinental sub-orbital trajectory as a payload.

Let's say that the average passenger and their luggage is 100kg (220 lbs). That's 770 passengers per flight, or about three 787s. And that seems not unreasonable, given the shot in the video of the tiny boat approaching the pad with the huge rocket.

Now, you're right that reusability is the key to cost savings. And I doubt it will be in the 10,000s range, but (i) that number may be a bit high when we're talking about Detroit to Tokyo flights, and (ii) it may be in the 1,000s range.
I think it's not unreasonable to suggest that the cost for a rocket ticket may get down to within an order of magnitude for a plane ticket.

Now, that said, with video chat and virtual reality getting better, I'm not sure how important intercontinental travel is going to be in the future anyway.

the_innkeeper:
Musk says that a falcon 9 costs the same to fuel as a large jet. If you look at a 787 and a380, you get anywhere from \$150000 to \$400000 for fuel costs.

We're not discussing Falcon 9. We're discussing BFR. Which has a 9m diameter and is in the same class as the Saturn V, the Mars passenger version's internal volume exceeding that of the Airbus 380 (so a sub-orbital version may even have a larger internal volume than that) and which burns methane, not kerosene, in a volume several times that of a Falcon 9 Heavy.

Theaetetus: the_innkeeper: A Falcon 9 can carry 7 passengers, for an unknown number of flights. Let's assume 100, for now. Total of 700 passengers for \$60M.

I think that's one of the assumptions that needs to be changed. The Falcon 9 can carry 22 thousand kg to LEO, with a delta-v of about 9.2 km/s. But we're not going to orbit - these are sub-orbital flights. A sub-orbital trajectory at maximum range (halfway across the world) requires a delta-v of about 7.9 km/s, and an intercontinental flight (5500km) requires only a delta-v of 6.1 km/s. Let's split the difference and say 7 km/s is going to be average for these flights. That's a 23% reduction in delta-v. But since the rocket equation includes a natural log, the resulting increase in payload is around 3.5 times, or 77 thousand kg to an intercontinental sub-orbital trajectory as a payload.

Let's say that the average passenger and their luggage is 100kg (220 lbs). That's 770 passengers per flight, or about three 787s. And that seems not unreasonable, given the shot in the video of the tiny boat approaching the pad with the huge rocket.

Now, you're right that reusability is the key to cost savings. And I doubt it will be in the 10,000s range, but (i) that number may be a bit high when we're talking about Detroit to Tokyo flights, and (ii) it may be in the 1,000s range.
I think it's not unreasonable to suggest that the cost for a rocket ticket may get down to within an order of magnitude for a plane ticket.

Now, that said, with video chat and virtual reality getting better, I'm not sure how important intercontinental travel is going to be in the future anyway.

Fiddling with your numbers gives the F9 the original cost of \$85000 cut down by a factor of 5500 (110 times more passengers * 50 times more flights (I picked 5000 as the mid-range plausible for your "1000s")) to a per-seat ticket price of \$15 bucks, and change.

I think your passenger maninfest is too large.

The wonderful travels of a turd: the_innkeeper:
Musk says that a falcon 9 costs the same to fuel as a large jet. If you look at a 787 and a380, you get anywhere from \$150000 to \$400000 for fuel costs.

We're not discussing Falcon 9. We're discussing BFR. Which has a 9m diameter and is in the same class as the Saturn V, the Mars passenger version's internal volume exceeding that of the Airbus 380 (so a sub-orbital version may even have a larger internal volume than that) and which burns methane, not kerosene, in a volume several times that of a Falcon 9 Heavy.

See Theaetetus' breakdown above. I will argue that a BFR may cost the same or less than a 787, and can carry those 700 passengers that Theaetetus spoke of.

What's the price comparison for Kerlox vs methalox?

the_innkeeper: Fiddling with your numbers gives the F9 the original cost of \$85000 cut down by a factor of 5500 (110 times more passengers * 50 times more flights (I picked 5000 as the mid-range plausible for your "1000s")) to a per-seat ticket price of \$15 bucks, and change.

I think your passenger maninfest is too large.

Could well be, but I think that, again, I'm within an order of magnitude. Suffice to say that it could potentially be affordable by regular folk, rather than just the five richest kings of Europe.

Theaetetus: the_innkeeper: Fiddling with your numbers gives the F9 the original cost of \$85000 cut down by a factor of 5500 (110 times more passengers * 50 times more flights (I picked 5000 as the mid-range plausible for your "1000s")) to a per-seat ticket price of \$15 bucks, and change.

I think your passenger maninfest is too large.

Could well be, but I think that, again, I'm within an order of magnitude. Suffice to say that it could potentially be affordable by regular folk, rather than just the five richest kings of Europe.
[img.fark.net image 316x174]

I would be more inclined to go with the 700 passengers on the BFR, but the flight count of 1000s still seems high to me. If Musk can get the reliability up, then he's golden. If not...

Mr. Eugenides: rcain: With his Hyperloop and Rocket Transportation Initiatives Musk stands to totally transform transportation around the world -- he also stands to monopolize it. These initiatives should NOT be Private, they should be done in concert with Local and National Governments to ensure the the Public is able to access these systems affordably and not be preyed upon by a Monopoly or Business Cartel

If he creates a faster, cheaper, safer alternative why shouldn't he become even more phenomenally wealthy?

That's not even remotely close to what I said

I said that it needs to be done in concert with Governments to make these PUBLIC FORMS OF TRANSPORTATION that are not the sole domain of a MONOPOLY

Or maybe you think it's a-ok to let one person or group of people to control means of transportation around the world? I would not be surprised if you said yes -- because it seems there are a lot of fascists these days that want to trample all over everyone else all in the name of "profit"

rcain: Mr. Eugenides: rcain: With his Hyperloop and Rocket Transportation Initiatives Musk stands to totally transform transportation around the world -- he also stands to monopolize it. These initiatives should NOT be Private, they should be done in concert with Local and National Governments to ensure the the Public is able to access these systems affordably and not be preyed upon by a Monopoly or Business Cartel

If he creates a faster, cheaper, safer alternative why shouldn't he become even more phenomenally wealthy?

That's not even remotely close to what I said

I said that it needs to be done in concert with Governments to make these PUBLIC FORMS OF TRANSPORTATION that are not the sole domain of a MONOPOLY

Or maybe you think it's a-ok to let one person or group of people to control means of transportation around the world? I would not be surprised if you said yes -- because it seems there are a lot of fascists these days that want to trample all over everyone else all in the name of "profit"

Actually, it's exactly what you said. Transportation options already exist. It's not like Musk would make those other options unavailable. If he makes something better, faster and cheaper, then so can anyone else.

But the way to prevent progress is to legislate it away.

Oldest | « | 1 | 2 | » | Newest | Show all

View Voting Results: Smartest and Funniest

Top Commented
Javascript is required to view headlines in widget.
1. Links are submitted by members of the Fark community.

2. When community members submit a link, they also write a custom headline for the story.