SpaceX News

Point out news stories, on the net or in mainstream media, related to polywell fusion.

Moderators: tonybarry, MSimon

paperburn1
Posts: 2454
Joined: Fri Jun 19, 2009 5:53 am
Location: Third rock from the sun.

Re: SpaceX News

Postby paperburn1 » Fri Sep 29, 2017 7:51 pm

concord cost would be about 5-6000 in today's dollars for the "cheap seats"
For about 1000 dollars I can fly to the philippines (20 to 36 +hours)
nonstop to sydney about 2 grand 27 hours
make those flights in under 1 hour..... priceless
I am not a nuclear physicist, but play one on the internet.

Skipjack
Posts: 6045
Joined: Sun Sep 28, 2008 2:29 pm

Re: SpaceX News

Postby Skipjack » Sat Sep 30, 2017 6:21 am

ladajo wrote:It was in the article on BFR that I linked (I think, much water under my bridge since then...)

Sooo... rough napkin math, stealing from a comment at the BFR video link...
~$100K in fuel per flight
Say 50% overhead on that per flight
100 pax (200lbs avg weight per pax = 20,000lbs pax cargo weight...hmmm...)
Roughly $1,500 per pax cost...

If I was an international airline, I would be really worried...
especially if he can fly 150 or 200 pax per flight... more a volume than cargo mass issue I think...

Musk mentioned 40 cabins for up to 120 passengers to mars. I am sure that assuming the extremely short flight time, he can fit in a lot more passengers. It has a pressurized volume of 825 m3, greater than an A380 cabin. So it should theoretically be able to carry close to 800 passengers.

paperburn1
Posts: 2454
Joined: Fri Jun 19, 2009 5:53 am
Location: Third rock from the sun.

Re: SpaceX News

Postby paperburn1 » Sat Sep 30, 2017 8:21 am

Personally I think the big problem is the regulations. Currently the FAA requires the ability to evacuate a plane within 90 seconds of the deployment of the evacuation slides. That in itself has been one of the reasons why planes haven't moved to more internal capacity. The airlines are pushing back; Airbus built the A380 (600 passengers 9500 miles range) because it believes in the hub and spoke concept of flying. That is, airlines will have smaller cities connect to main hub cities before flying to other large cities. Boeing’s 787 Dreamliner( 242 to 335 passengers 9100 miles range ) , on the other hand, is built under the idea of a point to point system. Which is exactly like it sounds, if you want to go from Hartford to London, you just go from Hartford to London. The 787 has a fuel efficiency of 102 miles-per-gallon per seat, while the A380 can only manage 74 mpg per seat. Those savings turned out to matter more than having more passengers. Even though that route is less popular than New York to London, airlines are able to fly it because they have a more nimble and fuel efficient plane in the 787. Another feature of the point-to-point aircraft is that in the summer time people wish to fly to Rome all the airline does the shuffle aircraft over to departure points for that trip to Europe and in the wintertime when people wish to fly to Mexico or other one warm destinations you can easily shuffle the airplanes to points to accommodate that flow of traffic and have muli flights in a day to better conform to passenger preference of flight departure time.. Hub traffic cannot do that easily. Note their variants of each type airplane hold more passengers and different ranges but basically the numbers work out the same regardless of size of variations. What really matters the airline is that the number of seats filled is at its maximum to maximize product profitability(this explains overbooking) and is a whole lot easier to fill a dream liner several times a day than it is to fill an A380 once. Also there is the cost and usability issue of the spacecraft. You can build an A380 $500 million and dreamliner for $300 million that have millions of miles service life and flight cycles. This is a tough market to break into. So while the rocket ship game sounds great on paper in reality the majority of the flying public does not care about the cost savings versus the time savings,but departing when they want to,where they want to and with as few plane changes as possible. The paperwork nightmare getting certified to run a rocketship point-to-point instead of hub to hub rocket transportation system leaves this rocket transportation system in the realm of little boys sci-fi books and ultrarich where time is literally money.
NOTE I choose these two AC because they both have the range to fly LA to anywhere in australia nonstop regulation / crew rest not factored in.
Last edited by paperburn1 on Sat Sep 30, 2017 12:33 pm, edited 1 time in total.
I am not a nuclear physicist, but play one on the internet.

paperburn1
Posts: 2454
Joined: Fri Jun 19, 2009 5:53 am
Location: Third rock from the sun.

Re: SpaceX News

Postby paperburn1 » Sat Sep 30, 2017 12:32 pm

I am not a nuclear physicist, but play one on the internet.

ladajo
Posts: 6204
Joined: Thu Sep 17, 2009 11:18 pm
Location: North East Coast

Re: SpaceX News

Postby ladajo » Sat Sep 30, 2017 1:07 pm

Great argument, however an hour is tough to beat. Even in a hub based model, which then uses, for example, hypertubes to spoke...
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)
What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)

Betruger
Posts: 2310
Joined: Tue May 06, 2008 11:54 am

Re: SpaceX News

Postby Betruger » Sat Sep 30, 2017 2:21 pm

At the very least the video's a best case scenario. The rest of the world will get iterations - between less optimal and nothing. E.G. Russia or China (ITAR?) and Caracas or Timbuktu (no market).

This would be a new Internet moment though. And elsewhere someone argues that rockets are still too pricey, because reality (as in above vid) adds the army of labor supporting their reusability etc. Like cars have the price of commuting (time spent not working etc), etc.
But this is what I'm instantly curious about, from that argument. Doesn't this, such an orbital access and worldwide travel costs decimator, comparably to what the internet did, enlarge the world's economy to make off world industrialisation a thing, even if as its very small first step?

For instance another person (iirc Jon Goff, Altius Space Machines, @ NSF forums) argued that it strains common sense to do this all SpaceX; that cooperation intercorporate and international is better. But does the scheme presented actually exclude that? It seems more like it says what SpaceX will do, fill in the business blanks as you will.
And also argues that unsegmented (just BFR+BFS in a few versions, e.g. no dedicated fuel depots) would be better. But again there's no such exclusion implied (is there?) and again if the BFS can cargo equivalent of a batch of Falcon 1's, errr, doesn't that kind of imply you can in fact put a serious industrial footprint up there in space?

Someone else (?) argues likewise the non lunar ISRU approach. But again? How does landing a BFS worth, so readily, exclude someone else using that BFS as means to bootstrap their Lunar ISRU ? Win-Win?? Doesn't the "Moon Base Alpha" quip sort of imply it?


TLDR
How close to the classic worldwide rules not applying anymore would we be, with the immediate implications of BFR/BFS access to space?
Is Musk expecting too little future shock from everyone else?
You can do anything you want with laws except make Americans obey them. | What I want to do is to look up S. . . . I call him the Schadenfreudean Man.

ladajo
Posts: 6204
Joined: Thu Sep 17, 2009 11:18 pm
Location: North East Coast

Re: SpaceX News

Postby ladajo » Sat Sep 30, 2017 2:52 pm

On a serious note, if he builds these, and is able to point cost per ticket in the same realm as airliners, and improves seat spacing, long haul aircraft are pointless, and the seating comfort argument alone is going to drive many a self promoting passenger to ditch airliners.

BFS + Hypertube is going to be a hard combination to beat for long haul options.

On another note, as I understand, passengers on airliners pay for gas, and air cargo pays the profit. Musk's BFRs are also going to attack air cargo viscously. However, to date, if time is less or not a factor, then ships and trains still can not be beat for large scale cargo moves.

My personal idea regarding the tube approach is to start it as port to distribution or manufacturing to port/distribution points cargo service before moving humans. The ROI would seem to be faster and you get a lower risk option to work out bugs and improve engineering based economy of scale.
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)

What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)

paperburn1
Posts: 2454
Joined: Fri Jun 19, 2009 5:53 am
Location: Third rock from the sun.

Re: SpaceX News

Postby paperburn1 » Sat Sep 30, 2017 9:59 pm

.Hypertube is something that could change the game. And the Chinese tourist trade would probably be a huge user this product. They tend to want to get their vacation started instantly, Mass. consume whatever products are available. And then jump back home. So I do see a potential market for this more like flying first class. At one point in time cars were just for the rich, trains just for the rich, ocean liners were just for the rich, planes were just for the rich. So I could see a point in the future or rocket travel slowly migrate is way down to the masses especially if we started having destinations that were off planet. Because somebody did say one hour is hard to beat :D
I am not a nuclear physicist, but play one on the internet.

happyjack27
Posts: 1435
Joined: Wed Jul 14, 2010 5:27 pm

Re: SpaceX News

Postby happyjack27 » Sun Oct 01, 2017 4:54 pm

if we compare BFR to traditional airline, all things being equal, the primary costs per passenger are fuel and maintenance.
if we set maintenance equal, we're down to fuel costs.

and now one can see that BFR saves fuel over an airline by going to a higher altitude and thus less air friction.

however, BFR uses rocket fuel whereas an airline uses jet fuel.

furthermore, airline engines are air-breathing, so they don't need to carry oxygen, thus reducing the mass significantly.

one wonders whether adding air breathing functionality to BFR could lessen the fuel cost without adding to much mass and maintenance. especially given that it only ever goes to LEO.

though the return trip would all be retro-propulsion, so would you need a reversable intake? OTOH, your mass would be less 'cause you've spent fuel, so your fuel need per delta-v would be less, so the payoff from air breathing wont be as great on the return trip.

ladajo
Posts: 6204
Joined: Thu Sep 17, 2009 11:18 pm
Location: North East Coast

Re: SpaceX News

Postby ladajo » Sun Oct 01, 2017 9:35 pm

BFR burns LOX (Cheap) and Kerosene (Fairly cheap). The kerosene is actually not that much different from Jet A-1.

While a rocket burns more fuel on a rate basis, it does so for significantly less time, and only really on the boost. There we find the big difference for long haul I think. Plus, from a maintenance perspective, rocket engines are much less complex than modern jets. My sense is that the longer term maintenance is going to be much less. Also, with economy of scale, and relative simplicity in comparison, replacement costs may well be much lower, and furthered by re-manufactured engines being used down the road. Probably the biggest expense will be in the turbo-pumps. This is all new ground, so it is hard to tell. Not enough data yet.
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)

What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)

kurt9
Posts: 562
Joined: Mon Oct 15, 2007 4:14 pm
Location: Portland, Oregon, USA

Re: SpaceX News

Postby kurt9 » Sun Oct 01, 2017 10:35 pm

Where is the information that shows that BFR sub-orbitals can compete with conventional sub-sonic airliners for intercontinental travel. Is it the NIAC presentation? What is the link?

I find it difficult to believe the economics of this sub-orbital transport (although having done my share of 10-14 hour flight, would certainly welcome it). Another issue that has not been brought up is the damage to the launch pad by the rocket both departing and landing. Airliners do not put this kind of stress on runways.

When I think of sub-orbital travel, I think of Phillip Bono's Rombus, Pegasus, and Ithaca designs for 30 minute travel from LAX to China. Does Musk really think he can pull this off?

happyjack27
Posts: 1435
Joined: Wed Jul 14, 2010 5:27 pm

Re: SpaceX News

Postby happyjack27 » Mon Oct 02, 2017 2:05 am

Another thing to consider is that a rocket's velocity at a given altitude is optimized for maximum fuel efficiency, considering the air pressure and thus friction. Basically it goes as fast as it can so long as that's below terminal velocity. The available thrust-to-weight ratio can then be taken into account so that you never have more acceleration than you need. This informs the number of rocket engines at each stage, and is why higher vertical stages have lower thrust-to-weight ratios.

(Thanks Kerbal Space Program.)

Not sure how this compares with an aircraft, but presumably one could optimize a rocket to reach LEO and then de-orbit, and then that optimization works the same between any two points on the planet, give or take the rotational velocity of the planet.

The launch trajectory is the optimized to get the most efficient angle, considering gravity and friction and target apopsis and eccentricity. At this point wings are useless because you're already at optimal lift (vertical) vs forward ratio the whole way.

On re-entry, however, aero-braking is your huge fuel-saver. Presumably the lower opportunity for aerobraking because of the smaller profile is a disadvantage to the rocket. Though after subtracting that, or rather adding that in fuel, the final difference is the deceleration on the runway by breaking, vs the cost to do that much deceleration propulsively, which is small.

Meanwhile on the airplane you have all that air friction as you're approaching the runway that is still working AGAINST you, hence your engines are still powered and providing FORWARD thrust. After you compensate for the advantage in aerobraking - which isn't that great because you're not going that fast -- all that forward thrust on the airplane after it passes the midpoint is done at a loss.

Maui
Posts: 577
Joined: Wed Apr 09, 2008 12:10 am
Location: Madison, WI

Re: SpaceX News

Postby Maui » Mon Oct 02, 2017 4:07 am

paperburn1 wrote:Personally I think the big problem is the regulations. Currently the FAA...


When first reading about Earth-to-Earth, I assumed the offshore platforms had to do with safety, noise, and lack of real estate for a launch site. But reading your post, I realize another very important reason... regulations. More than 12 nautical miles offshore, the FAA has no jurisdiction. Perhaps the US (or other country) has no jurisdiction at all, this is a little less clear to me. Certainly fewer regulations whatever the case. (Even if a county wanted to do something about sonic booms and launch noise, would they have the legal authority for launches in international waters?)

On this note, I've seen much made of the 30 min boat ride, but with less security regulations, I could see the security checks being done by teams that came to each cabin on the way out, and likewise for customs on the way in. This would actually be quite efficient and convenient.

Skipjack
Posts: 6045
Joined: Sun Sep 28, 2008 2:29 pm

Re: SpaceX News

Postby Skipjack » Mon Oct 02, 2017 12:22 pm

paperburn1 wrote:Personally I think the big problem is the regulations. Currently the FAA requires the ability to evacuate a plane within 90 seconds of the deployment of the evacuation slides. That in itself has been one of the reasons why planes haven't moved to more internal capacity. The airlines are pushing back; Airbus built the A380 (600 passengers 9500 miles range) because it believes in the hub and spoke concept of flying. That is, airlines will have smaller cities connect to main hub cities before flying to other large cities. Boeing’s 787 Dreamliner( 242 to 335 passengers 9100 miles range ) , on the other hand, is built under the idea of a point to point system. Which is exactly like it sounds, if you want to go from Hartford to London, you just go from Hartford to London. The 787 has a fuel efficiency of 102 miles-per-gallon per seat, while the A380 can only manage 74 mpg per seat. Those savings turned out to matter more than having more passengers. Even though that route is less popular than New York to London, airlines are able to fly it because they have a more nimble and fuel efficient plane in the 787. Another feature of the point-to-point aircraft is that in the summer time people wish to fly to Rome all the airline does the shuffle aircraft over to departure points for that trip to Europe and in the wintertime when people wish to fly to Mexico or other one warm destinations you can easily shuffle the airplanes to points to accommodate that flow of traffic and have muli flights in a day to better conform to passenger preference of flight departure time.. Hub traffic cannot do that easily. Note their variants of each type airplane hold more passengers and different ranges but basically the numbers work out the same regardless of size of variations. What really matters the airline is that the number of seats filled is at its maximum to maximize product profitability(this explains overbooking) and is a whole lot easier to fill a dream liner several times a day than it is to fill an A380 once. Also there is the cost and usability issue of the spacecraft. You can build an A380 $500 million and dreamliner for $300 million that have millions of miles service life and flight cycles. This is a tough market to break into. So while the rocket ship game sounds great on paper in reality the majority of the flying public does not care about the cost savings versus the time savings,but departing when they want to,where they want to and with as few plane changes as possible. The paperwork nightmare getting certified to run a rocketship point-to-point instead of hub to hub rocket transportation system leaves this rocket transportation system in the realm of little boys sci-fi books and ultrarich where time is literally money.
NOTE I choose these two AC because they both have the range to fly LA to anywhere in australia nonstop regulation / crew rest not factored in.

I think Musk is looking towards the military there, even if he is not saying it.
I am sure the DOD is very interested in the ability to rapidly deploy 800 soldiers to anywhere in the world within less than an hour. And on top of that, the thing lands vertically. It does not need a runway.

ladajo
Posts: 6204
Joined: Thu Sep 17, 2009 11:18 pm
Location: North East Coast

Re: SpaceX News

Postby ladajo » Mon Oct 02, 2017 1:57 pm

Maui wrote:
paperburn1 wrote:Personally I think the big problem is the regulations. Currently the FAA...


When first reading about Earth-to-Earth, I assumed the offshore platforms had to do with safety, noise, and lack of real estate for a launch site. But reading your post, I realize another very important reason... regulations. More than 12 nautical miles offshore, the FAA has no jurisdiction. Perhaps the US (or other country) has no jurisdiction at all, this is a little less clear to me. Certainly fewer regulations whatever the case. (Even if a county wanted to do something about sonic booms and launch noise, would they have the legal authority for launches in international waters?)

On this note, I've seen much made of the 30 min boat ride, but with less security regulations, I could see the security checks being done by teams that came to each cabin on the way out, and likewise for customs on the way in. This would actually be quite efficient and convenient.


The platform would need to be registered/flagged, and is subject to US regulations when operating within the US EEZ (200nm). So two approaches would drive regulatory requirements flag or EEZ operations. There are other regulatory requirements for operation on the seas both distance from shore driven as well as high seas UNCLOS and Customary International Law driven. One would NOT want to be considered stateless and operating on the High Seas. You would become a target of whomever wished to go after you...
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)

What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)


Return to “News”

Who is online

Users browsing this forum: No registered users and 17 guests