SpaceShipTwo

I will be happy to send small parcels by matter transporter, but if I have to send myself somewhere else on the planet ....



this sounds like the best ride!

I would think they are conventional, in the way he used the term. They are all chemical combustion rockets. Where as Buck rogers' engine is fusion.

White Knight should fly higher. Say 70 thousand feet. Would save on SS1's fuel.

It would if it could.

or a turbo-ramjet . it would weigh a lot less than a rocket because it wouldn't carry its own oxygen.

Bit of a problem when you run out of oxygen higher up in the atmosphere.

not necessarily-it can accelerate up to orbital velocity using the ramjet.
otherwise,maybe a small rocket to provide the necessary delta V out in space

Point to point suborbital, either packages or passengers, is a hard mission both for technical reasons and business reasons. You need to be able to go a long way downrange. 6000km minimum for transatlantic routes. Anything shorter won't close the business case. 20000km for antipodal range, the point directly on the opposite side of the earth. This takes a lot more delta V, and more reentry heating, than just going 100km straight up. It's not as hard as orbital, but its well out of reach for an x-prize vehicle.

On the business side you have to remember that customers want to buy point to point service where they specify the points. So you will need to be able to launch and land at a lot of different locations. Existing airports sound good? How are you going to launch and land? VTVL? You'll have to get a new regulatory and air traffic control regime accepted in every country where you want to operate. HTHL under existing regulations? Your wings, wheels, airbreathing engines, and 45 minutes of loiter fuel are now deadweight during the balistic portion of your flight, and your structures and TPS are heavier because they have to be aerodynamically shaped. Good luck making the delta V.

I'm sure you could make something that would work, but would it be profitable? Point to point will pay less per kg than orbital, although volume and revenue may be higher. And you have competition from conventional subsonic airplanes. With orbital you can charge what it costs because all of your competition is just as expensive. Point to point can't charge any more than the dollar value of the customer's time because there's already a much slower, much cheaper way.

It's certainly not impossible, but it's hard enough that no one's been willing to put down the cash to try. There's probably another Frederick W. Smith (founder of FedEx) out there somewhere who will figure out how to make it profitable. If it piques your interest I would encourage you to try if only as an excercise to the reader.

First - steps are discussed here. The first step are the XPRIZE vehicles. Once they are ready to fly the XPRIZE CUP will be an incentive to improve them as the second step. Some of the teams will find other incentives to improve their vehicles for other goals. Step by step point-to-point suborbital will be approached and then reached by some teams and the orbit by other teams.

Second - all development und step require finance, money. The teams will have to do marketing, advertisment, acqisition etc. I mentioned a special marketing consultant in other discussions here. He says that the teams first have to get the interest of visioneers, enthusiasts and one or two other groups I don't remember this moment. These persons don't ask for business or practical use. Look at Scaled Composites and The da Vinci Project and you see Visioneers and Enthusiasts. Look at other teams and you will see more of them. And the XPRIZE Foundation is a visioneer around all teams together.

Third - all that's going on today is research and development, testing. But the way of testing etc. is providing revenues too. This is making all a little bit easier and there is more potential service that might be sold. One day in the near future the vehicles will have matured up to providing significant practical use. And I mentioned coming oil shortness because of exhaustion in the near future earlier in this message board. So competition from subsonic airplanes might not be the point and additionaly time is a factor of competition too - suborbital point-to-point-flights are much fast than conventional subsonic flights. And it will be sufficient if suborbital vehicles form an integrated part of the world wide traffic infrastracture - the customers don't need to specify the points the suborbital have to land at. They consider the freight only and - if the customers are passengers - to reach the goal. They might be satisfied if the suborbital vehicle lands at a traffic node providing cars, busses, short-distance airplanes etc. carrying the customers to their final destination.



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)