SpaceShipOne Rockets To 68,000 Feet

ehartwell writes "According to Space.com, Scaled Composite's SpaceShipOne flew its first rocket-powered flight today, the 100th anniversary of the Wright Brothers' 12-second first flight. SpaceShipOne's engine burned for 15 seconds, pushing it to Mach 1.2 (930 mph) and a peak altitude of 68,000 feet. To win the X-Prize they need to reach 330,000 feet twice within 2 weeks."

Comments

Re:Looks bad for Carmack

[savuporo]

they're nowhere near completing assembly of their full-size rocket

On the contrary

IMO, they are quite far along, i'd expect a hover test in a week or two ( if not for the _damn_ holidays )
BTW, as you probably know, official X-Prize flight attempt has to be announced at least two months in advance, so everybody still has a chance, as Rutan hasnt made such announcement yet.

On the landing gear failure

[Woutepout]

It appears that White Knight had a landing gear problem on the previous flight as well. Knowing that most systems on the two craft are identical, this could mean that there is a (serious?) problem with the landing gear design. So they're probably in for a very thorough re-examination of the relevant systems. But they're probably on top of things and it's hard to say anything sensible about it without inside-information.

PRIVATE commercial supersonic flight yet to happen

[Julian Morrison]

Concorde was a state funded project, almost exclusively flown by state subsidised airlines bearing national badges (Air France and British Airways).

Re:What's the big deal about rocket science?

[Dr. Zowie]

It's not hard in principle. As they say, ``the Devil's in the details''. You've got a very hot, combusting mixture under high pressure, right next to large tanks of explosive rocket fuel, and everything has to be light, light, light to fly well -- so you use the lightest, thinnest metal you think you can get away with. And, of course, the metal has to operate at much higher temperatures than you normally encounter, and still have enough strength to avoid blowing up during thrust.

If the rocket didn't have to fly, you could just put loads of engineering margin into every part, and end up with something big and heavy but reliable. But you can't, because "big and heavy" won't get off the ground.

The sheer amount of power that has to converted from chemical to mechanical energy is staggering. In a liquid-fueled rocket engine, you have to push fuel into the chamber against the pressure of combustion. That turns out to be very hard, since you have to move a LOT of fuel and the pressure has to be HIGH for good efficiency. Just the pumping requires a major engineering effort to handle the power required to drive the pumps.

If you have cryogenic liquid propellants (the most efficient for tankage), you have all kinds of material-science problems from the temperature extremes. If you fly less exotic materials, like nitrous oxide, you have less mass margin because the tank is heavier.

Then there are all kinds of weird pitfalls like uneven distribution within the combustion chamber; uneven fuel/oxidiser mixing; choked fuel flow; accumulation of large volumes of fuel mix (which have an alarming tendency to explode later if they don't burn instantly); quenching of the burn by the amazing volume of stuff flowing into the chamber; eddies and cavitation in the turbulent flow out the throat of the engine; detonation (makes your car engine knock, makes your rocket explode); things shaking loose because of the engine's vibration; the nozzle itself starting to combust, ablate, or burn-through; and making a poorly designed nozzle that limits your thrust.

None of those things is unsurmountable -- it's having to get everything more or less right the first time that is the real kicker.