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Passenger market for suborbital, hypersonic transports.

Posted by: RGClark - Fri Apr 03, 2009 4:22 pm
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Passenger market for suborbital, hypersonic transports. 
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Post Passenger market for suborbital, hypersonic transports.   Posted on: Fri Apr 03, 2009 4:22 pm
I saw that this weeks Space Access '09 conference, http://www.space-access.org/ , will have several presentations by companies working on suborbital flights for tourism.
According to this article, Virgin Atlantic is planning on marketing just suborbital flights at $200,000 and it reports a survey said orbital flights might be commercially viable at $500,000:

Space tourism survey targets cost factor.
Online results hint at future price points for suborbital and orbital flights.
By Leonard David
Senior space writer
updated 4:53 p.m. ET, Tues., Oct. 3, 2006
"Pricey seats.
"So far, orbital space tourism has been the propelled
province of well-heeled millionaires. Even for projected
suborbital jaunts — up to the edge of space and return to
Earth — the price tag for a Virgin Galactic spaceliner
seat slaps your purse or wallet for roughly $200,000.
Several key results of the space tourism survey point out:
The prices of current space treks into suborbital and
orbital are generally too high at present, with only 7
percent registering for a suborbital flight and 4 percent
for an orbital adventure at current price levels.
Suborbital flights would really take off at $25,000, and
orbital flights at $500,000, if such price levels were
compatible with an operator’s business plan. If price were
not an issue, nearly two-thirds of the respondents would
want to go on a round-the-moon adventure."
http://www.msnbc.msn.com/id/15120091/

I want to argue here that it would be feasible to provide service also for a much larger market: suborbital, hypersonic passenger flights for transcontinental and intercontinental transportation.
A round trip cross-Atlantic ticket on the Mach 2 Concorde cost around $10,000. I don't think it's out of the question that a substantial number of business executives and wealthy vacationers would be willing to pay $100,000 to make a cross-Atlantic or cross-U.S. trip that took less than an hour, especially when it included making a short stint to space in the process.
Likewise I think there would be a substantial market at $100,000 per ticket for a trip to Asia that only took 2 or 3 hours, compared to a full day as it does now.

You can make a calculation for how much fuel you would need for a rocket flying horizontally to reach a certain distance by using the rocket equation for velocity:

Vf -Vi = Ve*ln(Mi/Mf), where Vf, Mf are the final velocity and final mass, and Vi, Mi are the initial velocity and initial mass, and Ve is the exhaust velocity. The formula still works for intermediate points in the trip where you burned only a portion of the fuel, where Vf and Mf are the values at these intermediate times.
Let's say you're burning propellant at a rate r kgs/sec. Then the mass of the vehicle at time t will be Mf = Mi-rt. I'll say the initial velocity Vi is zero, and let the velocity at time t be V(t). Then the formula becomes:

V(t) = Ve*ln[Mi/(Mi-rt)]. Then we can integrate this formula for velocity to get the distance traveled, S(t):

S(t) = Ve*t - (Ve/r)*(Mi-rt)*ln[Mi/(Mi-rt)]

This formula is for the case of constant thrust, where the acceleration will gradually increase since the mass is decreasing as the fuel is used up. It might be more comfortable for the passengers if instead we used a constant acceleration flight. This would be accomplished by making the fuel flow rate, and therefore thrust, decrease as the weight decreases. The formulas for this case can be constructed in an analogous fashion to those of the classic rocket equation. I haven't calculated it but my guess is the total fuel usage would be the same as for using the fuel at a constant rate.
In any case, I will assume that just as for SpaceShipOne it will have aerodynamic shape to allow lift so that most of this propulsion can go towards providing horizontal thrust. I didn't include the drag in this first order calculation of the constant fuel rate case, but it can be added in a more detail examination. You can reduce the drag by having the craft undergo the hypersonic flight at high altitude. You can save fuel to reach this altitude by using a carrier craft such as the White Knight for SpaceShipOne. Note that you don't have to use the fuel on the carrier craft or suborbital vehicle to get to a height of say 100 km, but only to get to high enough altitude to reduce the drag and heating on the vehicle at the hypersonic velocities.
XCOR is planning on using kerosene and LOX for their engines so I'll use this type of engine for getting the Ve number. Kerosene/LOX engines can have Isp of 360 s at high altitude, which I am assuming will be the only time the rocket will be used. So Ve will be in the range of 3600 m/s at high altitude.
Let's say you want to go across the continental U.S., 4500 km. For a first generation transport vehicle let's say it's comparable in size to SpaceShipOne about 1,000 kg empty and 3,000 kg fully loaded with fuel to carry one pilot and two passengers.
Let's put in some numbers in order to calculate the distance, S(t): say t = 2500 s, about 42 minutes, r = 1 kg/s, and Mi consists of a 1000 kg vehicle with passengers and 2500 kg fuel, for a total of 3500 kg. Then we calculate: S(t) = 3600*2500 - (3600/1)*(1000)*ln(3500/1000) = 4,490,000 meters, or 4,490 km. The time of 42 minutes compares to about 6 hours for a normal passenger jet to travel this distance.
The maximum speed would be Vf = 3600*ln(3500/1000) = 4500 m/s, or Mach 15, quite a high speed. The X-15 was able to reach Mach 6.7 and was planned on being able to reach Mach 8. It had an Inconel skin with a titanium frame to resist the heat loads at these high Mach numbers.
Still for Mach 15 you might need materials even more heat resistant. In this article Burt Rutan says SpaceShipOne's carbon composite structure would not be sufficient for even the Mach 6.7 speeds of the X-15:

X-15 and today’s spaceplanes.
by Sam Dinkin
Monday, August 9, 2004
http://www.thespacereview.com/article/204/2

Still carbon-carbon composites are used for the leading edges of the wings for the Space Shuttle which have to withstand the highest temperatures of re-entry even at Mach 25, so presumably would also work at Mach 15. These carbon-carbon composites became infamous though for how they fractured under impact by foam in the Columbia accident. It turned out they are even more brittle than fiberglass.
This is a bit puzzling because the type of carbon composites used extensively for example in modern race cars is actually more fracture resistant than steel. This makes them an ideal material for race cars since they have greater strength than steel while being more fracture resistant and at a fraction of the weight. I can only assume that at the time the shuttle was being designed, these highly fracture resistant carbon composites were not available. Then the recommendation for the thermal protection is the carbon-composites of this highly fracture resistant type.
For the vehicle to be useful as a transport craft it will have to be able to take-off and land at least at international airports. Airport safety managers might not be too enthusiastic about rocket takeoff at their airports, and certainly not enthusiastic towards deadstick landings. At least for the takeoffs this uncertainly be could ameliorated by the jet engine carrier craft.
For the landings I suggest these rocket craft also have their own small jet engines so that they can do powered landings. There are some lightweight jet engines that could work for our 1000 kg first generation craft. For instance there is the TRS-18-1 engine that can produce 326 pounds of thrust and only weighs 85 pounds:

Microturbo TRS-18-1
Engine Specifications.
http://www.bd-micro.com/FLS5J.HTM#ENGINE

Two of these would probably be sufficient for landing our 1000 kg rocket plane assuming at subsonic speeds the craft had a lift/drag ratio typical for jets, which can be at 10 and above.
A more high performance and more extensively tested jet engine to use might be the PW610F. This weighs 260 pounds and can produce 900 pounds of thrust:

Pratt & Whitney Canada PW600.
http://en.wikipedia.org/wiki/Pratt_%26_ ... nada_PW600

One of these would probably sufficient for our purposes. For this more high performance engine we might even be able to use it for takeoff to reach high altitude for the rocket plane, dispensing with the need for the carrier craft.
At this early stage, we would have separate jet engines and rocket engines. The jet intakes would be closed off when the rocket is operating and opened to be used only during low speed, subsonic flight. However, we can imagine with further development we would get a type of hybrid engine, as for example envisioned for the Skylon craft, where the jet and rocket engine are combined into one.


Bob Clark


Last edited by RGClark on Sun Apr 05, 2009 2:19 pm, edited 2 times in total.



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Post    Posted on: Sat Apr 04, 2009 11:03 am
Heating isn't much of an issue if you Scram while in the thin upper atmosphere, and decelerate there. The Space Shuttle decelerates in the thick lower atmosphere, and so needs a lot more shielding.


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Post    Posted on: Sat Apr 04, 2009 2:29 pm
Just saw this article on Rocketplane XP, which plans to offer suborbital, tourism rocket flights, while using jet engines for take-offs and landings:

Rocketplane reset
by Jeff Foust
Monday, November 5, 2007
Image
The revised Rocketplane XP design (above) is intended ultimately to be more competitive in the emerging suborbital space tourism conference.
http://www.thespacereview.com/article/994/1

The Second Space Age.
March 6, 2008
Patrick Mahoney
"Ready for a space cruise? The technology is taxiing to the runway."
http://machinedesign.com/article/the-se ... e-age-0306

Rocketplane XP's current design was modified from the original Lear Jet base airframe but still has the look of a passenger business jet, with a rocket in the tail.
It has some titanium and steel portions to withstand the heat of reentry in addition to an aluminum frame. This makes it heavier than a Lear Jet and it has to use a long military base runway for take-offs and landings. However, quite likely if it used all composite materials, as does SpaceShipOne, to replace the heavy steel, titanium, and aluminum it could take off and land from a standard sized airport runway.


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Last edited by RGClark on Sat Apr 04, 2009 10:33 pm, edited 1 time in total.



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Post    Posted on: Sat Apr 04, 2009 2:33 pm
The Europeans have also proposed a business jet model for a suborbital tourism rocket:

DATE:14/06/07
SOURCE:Flightglobal.com
PICTURES: Astrium aims for 2012 suborbital tourism flights.
By Rob Coppinger
Image
The space jet will take off from a conventional runway, powered by two jet engines, and fly to 39,300ft (12,000m), where it will ignite its liquid oxygen, methane rocket engine providing an ascent acceleration of 3g. After 80s the jet will reach 196,000ft and coast to its apogee.
http://www.flightglobal.com/articles/20 ... ights.html

Interestingly, they consider this as a precursor to a point-to-point transport.

Another article on the proposed Astrium rocketplane:

Space planes 'to meet big demand'.
By Jonathan Amos, Science reporter, BBC News
Monday, 17 March 2008, 13:38 GMT
"Aerospace giant EADS says it will need a production line of rocket planes to satisfy the space tourism market."
http://news.bbc.co.uk/2/hi/science/nature/7298511.stm

There is a link to a nice video of a simulated flight on this page. In the video the passengers are wearing helmets with closed visors. But it doesn't look like they are wearing actual spacesuits with independent air supplies because the helmets are not connected to the rest of the suits. The helmets have more the look of motorcycle helmets. I don't know if this is really supposed


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Post    Posted on: Sat Apr 04, 2009 3:00 pm
I think the global market for intercontinental rocket trips at $100k is substantially smaller than people suppose. Why in the age of ever improving vido conferencing and beter international communications do business people need to travel in person?

While there is probably a market for the super rich elite this will probably not translate into thousands of fare paying customers travelling daily.

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Post    Posted on: Sat Apr 04, 2009 4:02 pm
Andy Hill wrote:
I think the global market for intercontinental rocket trips at $100k is substantially smaller than people suppose. Why in the age of ever improving vido conferencing and beter international communications do business people need to travel in person?
While there is probably a market for the super rich elite this will probably not translate into thousands of fare paying customers travelling daily.


Thanks for the response. And also for the pic of the Ascender which I hadn't seen before:

Bristol Spaceplanes - Ascender.
Image
http://www.bristolspaceplanes.com/proje ... nder.shtml

There have been several studies showing just for tourism there would a sufficient market for it to be profitable. I have to think there would be a bigger market for cases where the traveler would actually want to go somewhere and this method could get him there in 1/10th the time.
As a point of comparison I did a search on the Japan Airlines site for round trip business class tickets from my town of Philadelphia to Tokyo.
It ranged from $6,600 to $21,000:

Quote:
Select Your Flights

Philadelphia to Tokyo Thursday, April 9, 2009
Tokyo to Philadelphia Tuesday, April 14, 2009
Travelers: 1
Travel class: Business and First

Select your fare: Price differences within a fare type may be due to flight connections or availability. Prices are per adult passenger and include Taxes and Surcharges.

Fare type Fare description Lowest price
Business Saver Special Restricted. Bed-style seating on most long-haul routes -
Executive Class. more details $6,672.48
Business Saver Restricted. Bed-style seating on most long-haul routes -
Executive Class. more details $7,611.48
Business Normal Flexible. Bed-style seating on most long-haul routes -
Executive Class. more details $12,330.48
First Normal Flexible. World-renowned service and comfort - First Class.
more details $21,589.48



Note also, that the $200,000 ticket price mentioned for suborbital flights on SpaceShipOne is only for the first few flights. After, a few years the price is expected to come down to $20,000.


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Post    Posted on: Sun Apr 05, 2009 10:01 am
Hey guys

Just seen this video, may be of some interest!
http://www.european-spacetourism.eu/index2.html

Enjoy!

:)

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Post    Posted on: Sun Apr 05, 2009 10:52 am
RGClark wrote:
Note also, that the $200,000 ticket price mentioned for suborbital flights on SpaceShipOne is only for the first few flights. After, a few years the price is expected to come down to $20,000.


I think that, like Elon Musk, Virgin Galactic will find that there is unlikely to be huge savings for each seat flight, that's not to say that there wont be some cost reductions; probably something like a factor of three would be my guess (though I must stress that is based on my own gut feeling). All companies claim future reductions but an order of magnitude saving is not realistic IMHO.

Another thing to consider is that we are all looking from a space enthusiast point of view, most business men would not wish to strap themselves in a small light weight rocket powered craft just to save a few hours and probably their personal insurance would not cover such an activity.

So from my point of view I see no market for business travel and only a small one for space enthusiasts ( I myself would be tempted at a low enough price, but even $20,000 is to much to spend on a joy ride for most people).

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Post    Posted on: Sun Apr 05, 2009 1:42 pm
Rob Goldsmith wrote:
Hey guys

Just seen this video, may be of some interest!
http://www.european-spacetourism.eu/index2.html

Enjoy!

:)



Thanks for that. I hadn't heard of them before. I noted in their simulated video of the trip, it has the passengers wearing oxygen masks.

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Post    Posted on: Sun Apr 05, 2009 1:52 pm
Andy Hill wrote:
RGClark wrote:
Note also, that the $200,000 ticket price mentioned for suborbital flights on SpaceShipOne is only for the first few flights. After, a few years the price is expected to come down to $20,000.


I think that, like Elon Musk, Virgin Galactic will find that there is unlikely to be huge savings for each seat flight, that's not to say that there wont be some cost reductions; probably something like a factor of three would be my guess (though I must stress that is based on my own gut feeling). All companies claim future reductions but an order of magnitude saving is not realistic IMHO.
Another thing to consider is that we are all looking from a space enthusiast point of view, most business men would not wish to strap themselves in a small light weight rocket powered craft just to save a few hours and probably their personal insurance would not cover such an activity.
So from my point of view I see no market for business travel and only a small one for space enthusiasts ( I myself would be tempted at a low enough price, but even $20,000 is to much to spend on a joy ride for most people).


Possibly. But I would like to see a market study on the possibility.
I presume that if Japan Airlines gives that $21,000 ticket price on their ticketing site, then that is an actual option available, not for show. Notice you get "bed-like" seating on these day-long flights. Then it would be quite understandable that a business exec might want to pay $20,000 each way for a straight-flight that takes only 2 hours rather than using up a whole day each way and paying $20,000 round trip costs.


Bob Clark


Last edited by RGClark on Sun Apr 05, 2009 2:27 pm, edited 1 time in total.



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Post    Posted on: Sun Apr 05, 2009 2:14 pm
In this animation of the SpaceShipTwo trip, the passengers also do not appear to be wearing actual spacesuits, though they do have helmets:

Virgin Galactic SpaceShipTwo Animation.
http://www.youtube.com/watch?v=Cw1WaW8JsFs


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Post    Posted on: Sun Apr 05, 2009 2:59 pm
i think the helmets will be equipped with cameras etc, so the person gets a dvd of their experience from their perspective.

Rob

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Post    Posted on: Sun Apr 05, 2009 4:06 pm
A couple of things:

- The carrier plane needs time to get up to altitude. WK2 takes about an hour I think. So for all the advantages you get an extra hour of flight time as well.

- During this 26 hour trip, the modern executive can get a heck of a lot of work done if (s)he has a bit of private space, a network connection (even if it's just email) and a phone line. So those 26 hours don't go to waste. I don't see anyone working while strapped into a tiny spaceplane. Spending time in an aeroplane isn't so bad as long as you can be useful, and you can be useful for most of the trip.

- The economics of business trips are quite different from the economics of tourism. For tourism, all you need is someone willing and able to burn a lot of money. And since part of the attraction is that you're doing something pretty unique, the value will go up with the price to some extent. For a business trip, it has to make economic sense. I don't see why the reports for space tourism would say anything about business trips, and I don't see the wow-factor entering into business trips. These people fly so much that even a suborbital hop gets boring quickly.

- Formula 1 crashes used to end with bent steel in the old days, and injured or killed drivers. Today they end in a cloud of carbon dust, and the drivers are fine, because the pulverisation of the carbon absorbs energy much more efficiently. Carbon flexes less than steel, but as a consequence is more brittle. Another good example was the stage from Singapore to Qingdao in this year's Volvo Ocean Race. Slamming the hull on the waves in a storm led to three boats seeking shelter in Taiwan with serious hull damage. Of the other four, only one successfully sailed through the storm, all the others took shelter and waited it out. It must be said though that these VO70 boats aren't designed for sailing upwind or in that much breeze. Anyway, I'm not seeing much evidence of this carbon's ability to stay in one piece under the shock of impact. And then you're assuming that the RCC in the Shuttle's wing, which is presumably engineered for heat resistance, is the same material as that used in Formula 1 cars, which is probably engineered for strength vs. weight. Will a Formula 1 car survive reentry? Will the Shuttle survive an F1 crash?

- How many times has Rocketplane changed their design now? Are they ever going to fly anything, or do they only do design changes? I know, easy for me to say sitting at my desk, but I'll believe it when I see it.


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Post    Posted on: Sun Apr 05, 2009 11:15 pm
Also, Virigin can support Virign Galactic for the same reason VW supports the Buggati Veyron. VW *loses* $2 million everytime they sell a Veyron. So why do they do it? It boosts the VW brand enormously to be makers of the world most powerful production car.

If Virgin Galactic can even just break even witha small passenger population it will have more than justified itself by associating Virgin with advanced aeronautics and the future of human space flight.

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Post    Posted on: Mon Apr 06, 2009 8:04 am
idiom wrote:
If Virgin Galactic can even just break even witha small passenger population it will have more than justified itself by associating Virgin with advanced aeronautics and the future of human space flight.


Why would that be important to Virgin? VW support an expensive sports car because it improves people's perception of their other cars. Virgin is a service provider not a manufacturer so this wont work in the same way. At the moment the publicity gained from the venture will be worth the cost but this will not last indefinitely and will soon fade when flights become regular and should there be a fatal accident then the adverse publicity will make Virgin Galactic a liability to the parent company.

This is what I was saying with regard to looking at things from the view point of a space enthusiast without making an allowance that others do not see space in the same way. Virgin does not want to push the frontiers of space travel, they want to make money and if this venture is not profitable they will stop it.

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