[Colonol Dekker]

We need to hypnotise Gates somehow into funnelling his bank interest into this being mass produced.
 
On a semi related note (future-now etc) I saw at edenproject.com that you can buy a toy car with a tiny hydrogen fuel cell and a tiny solar hydrogen plant. For ninety quid.
 
Discuss take two.

[Thaeris]

I see these projects as first steps to attaining practical, economical, mass space operations. Regardless of whether or not the SpaceShipTwo project continues, the launch platform is undeniably a terriffic system for experiments or ferrying other launch vehicles... and it's stressed to carry a payload greater than the current launch vehicle... 

The real prize is getting an air-launched vehicle to enter orbit with a useful/living payload. When we can do that, we'll be one step closer to expanding our presence in the solar system, and maybe just a hair closer to expanding in our galaxy. 

[Kosh]

The time saved in crossing the ocean in the spaceship would be eaten into by the ime it'd take to get from your destination (say,  New York) to New Mexico, and then from wherever China's theoretical spaceport might be (presumablythe south of the country, although near-equatorial launches might not be neccesaryfor spaceplanes the way they are for rockets) to where you want to go. Not to mention the inonvenience of changing planes twice or more. It'd all add up - even conservatively, giving yourself say, an hour and a half in the air for each sub trip, half an hour to board each plane and get takeoff clearance, you're looking at a 6 or 7 hour trip. Time's saved for sure, but is it enough to justify the presumably massive price tag for the individual flights and the facilitys to launch these vessels? (The new mexico one is costing 200 illion) I just don't see there being enough of a market for it, even if you're dual using facilities for tourism and travel.

That presumes a lot of things. You're assuming there would only be one spaceport per country, which may not neccisarily be the case. Spaceports also do not have to be near the equator, it makes things easier but it isn't a requirement. It just means they will take a smaller number of people.

Also I don't know about you, but if it takes 6-7 hours to go to say beijing from san francisco, that's still a 50% time savings, many people consider it significant.

[Nuke]

Awesome. But $200,000 is a bit more than I can afford

Although... If they can make more than just the prototype, I wouldn't be surprised if the costs went down significantly.

space ship one was the prototype, this is the actual production model.

Spaceports also do not have to be near the equator, it makes things easier but it isn't a requirement. It just means they will take a smaller number of people.

i was actually kinda shocked that i found out my icy state has a spaceport out on kodiak island. probibly for launching satellites into those trickey polar orbits. still it doesnt change the fact that space ship two's technology is not really suited to any kind of long range operation. realistically speaking if you wanted to save time flying id first eliminate all the stops. start by getting rid of the idea of a centralized hub. you could instead come up with a small jet aircraft with stol capability which can operate out of small airports and private airstrips with global range. then you think you can probibly charter a gulfstream 5 for a lot less than an ss2 ticket.

[Janos]

The time saved in crossing the ocean in the spaceship would be eaten into by the ime it'd take to get from your destination (say,  New York) to New Mexico, and then from wherever China's theoretical spaceport might be (presumablythe south of the country, although near-equatorial launches might not be neccesaryfor spaceplanes the way they are for rockets) to where you want to go. Not to mention the inonvenience of changing planes twice or more. It'd all add up - even conservatively, giving yourself say, an hour and a half in the air for each sub trip, half an hour to board each plane and get takeoff clearance, you're looking at a 6 or 7 hour trip. Time's saved for sure, but is it enough to justify the presumably massive price tag for the individual flights and the facilitys to launch these vessels? (The new mexico one is costing 200 illion) I just don't see there being enough of a market for it, even if you're dual using facilities for tourism and travel.

That presumes a lot of things. You're assuming there would only be one spaceport per country, which may not neccisarily be the case. Spaceports also do not have to be near the equator, it makes things easier but it isn't a requirement. It just means they will take a smaller number of people.

Also I don't know about you, but if it takes 6-7 hours to go to say beijing from san francisco, that's still a 50% time savings, many people consider it significant.

Do you consider time spent in airports in obligatory security bull**** etc. as a part of travel time?

[Kosh]

I was using his numbers, so I dont know.

[Thaeris]

We'll still have to wait a while for practical space planes. These little tourism hops don't really have much practical range - they expend their energy going up, not in any particular lateral direction. That's why they're sub-orbital. They get to a high alt above the planet, but then they just come back down afterwards. They just don't have the capacity within them to travel farther or get into orbit.

So no, SpaceShipTwo does NOT have the potential to take you to china in two hours from a distant point. It just flies up, then glides down. 

[Nuke]

like i said, charter a gulfstream 5, its cheaper (and they haul ass).

[BengalTiger]

100 years ago, when aviation enthusiasts said that some day planes would go across the Atlantic in a single day, many times faster than an ocean liner and even took over the role of shipping people from Europe to the USA and back, some people didn't believe, others said it would be too expensive, and everything else that was written in this thread was also said back then.

I won't be surprized if 20 years from now my flight flight from Poland to the US lasted 3 hours and reached 50-70 km above sea level.

[redsniper]

I don't think anyone's saying we won't have 3 hour flights from US to Poland someday. They're just saying it won't be with Spaceship Two.

[Thaeris]

Yalp. SS2, like all these other little commercial tourism jobs, just goes up a little... It doesn't have the longitudal velocity to go any useful distance over land. It just flies up and comes down, as said before. However, it's a fantastic step forward. Now, if you could combine a light, cheap air-launched vehicle with the neccessary propulsion systems, you might just get a great orbital delivery vehicle.

Here's a cool thought: Manufacture a ramjet with what amounts to a solid propellant. The propellant is fairly light, it already has an oxidizer (the atmosphere), and all it needs is a little additional forward velocity and to be ignighted once at speed. You get the additional velocity you need via JATO/RATO, though the acronym is a little inaccurate as you're not taking off. Once at speed, the solid fuel in the ramjet is ignighted, burning off as the previous layer has been burned... you get the idea. Once at critical altitude, the ramjet drops off the ship and the main engine is engaged. Congratulations, now you've managed the velocity you need to get into orbit... 

[Kszyhu]

Well, there is an interesting project of single-stage to orbit spaceplane, which probably everyone knows about: http://en.wikipedia.org/wiki/Skylon. I think that SS2 and following planes will be focused on small-scale personnel transport, with Skylon or similar designs as cargo hauler.

[headdie]

i read about that a few months ago, the concept for the engines is brilliant and if they pull it off means Britain might actually have a notable contribution to space flight

[Nuke]

pretty impressive engine. looks way better than scram. also unlike scram you could fly the whole mission only on one set of engines.

[Thaeris]

I almost forgot that I had this...

[attachment deleted by admin]

[Nuke]

whats witht he funky shape of the engine nacelles? is that to direct thrust downward or to allow the structure to generate aerodynamic lift?

[Thaeris]

I can't say, Nuke.

This is an X-Plane model, and I believe the author of the model did his research to a fairly extensive degree with the available published materials. The nacelle design might have also been to angle the exhaust down a little, allowing the craft's AoA to remain at a more reasonable angle while still providing thrust at a greater degree upwards.

[Nuke]

that might be so. when you have high power at high altitude an aircraft can become rather lift happy. you may not want to rise up to high while you accelerate. flying scram engines in orbiter for example, you kinda have to stay in a certain sweet spot, which is not easy because all the ship wants to do is climb. this would allow the vehicle to keep its nose below zero aoa to keep it in the zone while it accelerates to the desired velocity. essentially you want to get as close to orbital velocity as you can while using the airbreathers.

http://en.wikipedia.org/wiki/Reaction_Engines_SABRE
heres an article on the engine. it has a good cutaway image, but with the odd shape its kinda hard to tell if the engines are angled down or not. it might also be to better angle the shock cones into the airstream.

[Thaeris]

Hmmm...

Well, as you are imaginably well aware, at high alts the atmosphere is quite thin, so your AoA might have more to due with the lift you're getting than anything else. Furthermore, most high-speed aircraft use symmetrical, close to symmetrical, or other types of "neutral" airfoils, so lift is generally closely related to your angle of attack, barring fuselage lift, of course. At extreme speeds and high altitudes, the rise the aircraft is experiencing might be due to (a.) the reduced gravitational attraction between the aircraft and the planet and (b.) the fact that the aircraft's speed is so great that it's starting to pull away from the planet - as you said, you're trying to attain extreme velocities while still remaining in the atmosphere. Condition (a.) is somewhat arbitrary, as you really need to get far out to have that as a factor, but I think (b.) is a likely case, especially when you're going like, oh, Mach 8 or greater...

The whole "lift-happy" thing is assumably just an incorrect assessment based on a reasonable observation.

[Nuke]

both airspeed (squared) and air density are proportional to the lift produced by the airfoil. the basic lift formula is pretty much Cl * V^2 * D * A * 0.5, where Cl is the coefficient of lift, V is the airspeed, D is the air desnity, and A is the wing area, so velocity plays a much larger role hin how much lift is produced than density. aoa increases the Cl by about 0.11 per degree over 0 (and inversely for negative aoa) until a stall occures. 0.11 is pretty much used as a slope constant for non-stall wing operation since all airfoils seem to have the same slope for some reason.  as for gravity, it basically follows the inverse square law. gravity doesnt very by much within the atmosphere. still it is a factor. i learned all this stuff while working on my atmospheric flight script. most of it works but im sure theres some flaws in my understanding of the physics.