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Passenger market for suborbital flights.



 
 
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  #1  
Old April 2nd 09, 02:14 PM posted to sci.astro,sci.physics,sci.space.policy,sci.materials
Robert Clark
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Posts: 1,150
Default Passenger market for suborbital flights.

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.
First 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_%...y_Canada_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
  #2  
Old April 5th 09, 02:28 PM posted to sci.astro,sci.physics,sci.space.policy,sci.materials
Robert Clark
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Posts: 1,150
Default Passenger market for suborbital flights.


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

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...space-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.


Bob Clark
  #3  
Old April 5th 09, 02:29 PM posted to sci.astro,sci.physics,sci.space.policy,sci.materials
Robert Clark
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Posts: 1,150
Default Passenger market for suborbital flights.

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
"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...m-flights.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


Bob Clark
  #4  
Old April 5th 09, 02:32 PM posted to sci.astro,sci.physics,sci.space.policy,sci.materials
Robert Clark
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Posts: 1,150
Default Passenger market for suborbital flights.

Another suborbital, tourism rocket plane based on a business jet
model:

Bristol Spaceplanes - Ascender.
http://www.bristolspaceplanes.com/pr...ascender.shtml

There have been several studies showing just for tourism there would
be a sufficient market for such suborbital flights 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:

================================================== =
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 fa 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.


Bob Clark
  #5  
Old April 8th 09, 12:50 PM posted to sci.astro,sci.physics,sci.space.policy,sci.materials
Robert Clark
external usenet poster
 
Posts: 1,150
Default Passenger market for suborbital flights.

On Apr 5, 9:32*am, Robert Clark wrote:
Another suborbital, tourism rocket plane based on a business jet
model:

Bristol Spaceplanes - Ascender.http://www.bristolspaceplanes.com/pr...ascender.shtml

There have been several studies showing just for tourism there would
be a sufficient market for such suborbital flights 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:

================================================== =
* * 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 fa 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.



In their usual good reporting, the BBC discusses directly the safety
issues for these suborbital tourism flights:

Space ships: the next generation - Space Tourist- BBC Science &
Nature.
http://www.youtube.com/watch?v=g_ROk...eature=related

Bob Clark
  #6  
Old April 8th 09, 01:20 PM posted to sci.astro,sci.physics,sci.space.policy,sci.materials
Robert Clark
external usenet poster
 
Posts: 1,150
Default Passenger market for suborbital flights.

On Apr 8, 7:50*am, Robert Clark wrote:

*In their usual good reporting, the BBC discusses directly the safety
issues for these suborbital tourism flights:

Space ships: the next generation - Space Tourist- BBC Science &
Nature.http://www.youtube.com/watch?v=g_ROk...eature=related


In this animation of the SpaceShipTwo suborbital flight, the
passengers do not appear to be wearing actual spacesuits, though they
do have helmets:

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


Bob Clark

  #7  
Old April 8th 09, 01:21 PM posted to sci.astro,sci.physics,sci.space.policy,sci.materials
Robert Clark
external usenet poster
 
Posts: 1,150
Default Passenger market for suborbital flights.

On Apr 8, 7:50*am, Robert Clark wrote:

*In their usual good reporting, the BBC discusses directly the safety
issues for these suborbital tourism flights:

Space ships: the next generation - Space Tourist- BBC Science &
Nature.http://www.youtube.com/watch?v=g_ROk...eature=related


Another suborbital tourism project was posted on the
SpaceFellowship.com forum:

Project Enterprise.
http://www.european-spacetourism.eu/index2.html

I noted in their simulated video of the trip, it has the passengers
wearing oxygen masks.


Bob Clark

  #8  
Old April 19th 09, 09:33 AM posted to sci.astro,sci.physics,sci.space.policy,sci.materials
Robert Clark
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Posts: 1,150
Default Passenger market for suborbital flights.

This site is an informative compendium of articles related to space
flight, and particularly space tourism:

SPACE FUTURE.
http://www.spacefuture.com/home.shtml

Here's an article re-printed on the site on commercial orbital and
suborbital flights:

New Commercial Opportunities in Space.
D M Ashford
The Aeronautical Journal, February 2007.
"Of aeroplanes that have actually flown, and with the possible
exception of SpaceShipOne, the one most suitable for providing the
basis of a space tourism industry is perhaps the Saunders Roe SR.53
rocket fighter that first flew in 1957. This is probably the most
practical rocket-powered aeroplane yet built.
If it had entered service, the RAF would soon have had a mature
rocketplane with long life and rapid turnaround. With straight-forward
development, the SR.53 could have had sub-orbital performance. Indeed,
when it was cancelled as a fighter in 1958, Saunders Roe did propose a
space research variant(17)."
http://www.spacefuture.com/archive/n...al_space.shtml

Note that that the example of the Saunders Roe SR.53 shows that an
aircraft can successfully operate with both rocket and jet engines.

Bob Clark
  #9  
Old April 20th 09, 04:46 AM posted to sci.astro,sci.physics,sci.space.policy,sci.materials
Robert Clark
external usenet poster
 
Posts: 1,150
Default Passenger market for suborbital flights.

On Apr 19, 4:33*am, Robert Clark wrote:
*This site is an informative compendium of articles related to space
flight, and particularly space tourism:

SPACE FUTURE.http://www.spacefuture.com/home.shtml

Here's an article re-printed on the site on commercial orbital and
suborbital flights:

New Commercial Opportunities in Space.
D M Ashford
The Aeronautical Journal, February 2007.
"Of aeroplanes that have actually flown, and with the possible
exception of SpaceShipOne, the one most suitable for providing the
basis of a space tourism industry is perhaps the Saunders Roe SR.53
rocket fighter that first flew in 1957. This is probably the most
practical rocket-powered aeroplane yet built.
If it had entered service, the RAF would soon have had a mature
rocketplane with long life and rapid turnaround. With straight-forward
development, the SR.53 could have had sub-orbital performance. Indeed,
when it was cancelled as a fighter in 1958, Saunders Roe did propose a
space research variant(17)."http://www.spacefuture.com/archive/new_opportunities_in_commercial_sp...

*Note that that the example of the Saunders Roe SR.53 shows that an
aircraft can successfully operate with both rocket and jet engines.



More on the Saunders-Roe SR.53:

Saunders-Roe SR.53.
http://en.wikipedia.org/wiki/Saunders-Roe_SR.53


Bob Clark
  #10  
Old April 20th 09, 04:58 AM posted to sci.astro,sci.physics,sci.space.policy,sci.materials
Androcles[_8_]
external usenet poster
 
Posts: 1,135
Default Passenger market for suborbital flights.


"Robert Clark" wrote in message
...
On Apr 19, 4:33 am, Robert Clark wrote:
This site is an informative compendium of articles related to space
flight, and particularly space tourism:

SPACE FUTURE.http://www.spacefuture.com/home.shtml

Here's an article re-printed on the site on commercial orbital and
suborbital flights:

New Commercial Opportunities in Space.
D M Ashford
The Aeronautical Journal, February 2007.
"Of aeroplanes that have actually flown, and with the possible
exception of SpaceShipOne, the one most suitable for providing the
basis of a space tourism industry is perhaps the Saunders Roe SR.53
rocket fighter that first flew in 1957. This is probably the most
practical rocket-powered aeroplane yet built.
If it had entered service, the RAF would soon have had a mature
rocketplane with long life and rapid turnaround. With straight-forward
development, the SR.53 could have had sub-orbital performance. Indeed,
when it was cancelled as a fighter in 1958, Saunders Roe did propose a
space research
variant(17)."http://www.spacefuture.com/archive/new_opportunities_in_commercial_sp...

Note that that the example of the Saunders Roe SR.53 shows that an
aircraft can successfully operate with both rocket and jet engines.



More on the Saunders-Roe SR.53:

Saunders-Roe SR.53.
http://en.wikipedia.org/wiki/Saunders-Roe_SR.53


Bob Clark
====================================
Note that the example of the 1940s German V1 shows that an
aircraft can successfully operate with both rocket and jet engines.
http://www.battlefield-site.co.uk/V1cutaway.gif
Big hairy deal.


 




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