SpaceShipOne beats X-15

[Dr Mordrid]

IF confirmed the 358,000 ft. altitude reached by SpaceShipOne in flight 1 of its X-prize attempt will have exceeded the top altitude achieved by the X-15 in 1963: 354,200 ft.

Rock on guys

Dr. Mordrid

[Paddy]

nice

So they have to make the second flight within two weeks?

[Dr Mordrid]

Yes. In Rutans interview during the webcast he was talking Sunday or Monday with the latter being the most probable.

Interesting point is that in todays flight he stopped the engine 11 seconds early, so he likely could have exceeded 400,000 ft.

Also interesting is that they have even larger engines in the garage

Dr. Mordrid

[KRSESQ]

Next stop: LEO.

I recall hearing that the X15 pilots were ordered to keep it "low and slow" so as not to upstage NASAs Mercury 7.

Kevin

[Dr Mordrid]

The X-15's were ordered not to go faster/higher because they started burning through the fuselage. This was due to the Mach 6+ speeds achieved at the end of the program dispite a full-bird ablative coating.

Dr. Mordrid

[KRSESQ]

You're right, of course. the X-15s got beastly hot in flight. It was a major problem that probably contributed to the demise of the entire program more than anything else.

I wish I could remember the name of the documentary that put out the political angle. It aired (probably on Nova) back when "The Right Stuff" was big.

Which raises the question of what they intend to shield SpaceshipOne with when it makes the next big leap? Or do they have something new on the drawing boards?

Kevin

[Dr Mordrid]

My bet is that Rutan will come up with some solution NASA would never seriously consider. This seems to be his goal in life

Dr. Mordrid

[KRSESQ]

One possible solution explored during the X-30 (?) program of the early 90s was to pipe LH through the fusilage during reentry for cooling. I can imagine what a plumber's nightmare THAT would have been!

Kevin

[Dr Mordrid]

Well...SS1 certainly can get down from the altitude Columbia burned up at without a shield, but then it was only going 2,500+ mph and not 12,000+ mph.

Maybe having a large re-entry engine capable of a protracted burn long enough to get it down to manageable speeds, after which it could use the feather technique?

To my mind feathering is nothing short of a brilliant idea.

Let's not forget that they are using a a VERY lightweight construction mainly consisting of reinforced foam, which should decelerate rather easily. That combined with their very inexpensive hybrid engines, which seem to be getting better all the time, could provide just the kick to do this.

Blows my mind that you can do space flight using laughing gas and rubber for fuel and still be throttleable and re-startable. No finickey turbo pumps and no cryogenics. Amazing.

Dr. Mordrid

[KRSESQ]

Spacecraft on re-entry have typically relied on the atmosphere to provide braking. I've often wondered what effect a very-low-speed re-entry would have on spacecraft heating.

I'm inclined to believe that it would take almost as much fuel to decellerate the ship to the point that atmospheric heating would be negligable, as it would to boost it to orbital velocity in the first place!

My brother is a rocket scientist (!! ). I should pose the question to him.

Kevin

[KvHagedorn]

Originally posted by KRSESQ
One possible solution explored during the X-30 (?) program of the early 90s was to pipe LH through the fusilage during reentry for cooling. I can imagine what a plumber's nightmare THAT would have been!

Kevin

Why the hell do they always think up the most ridiculously expensive-sounding solutions? Yeah, I know, because the aerospace lobbiests tell "our" congress what to do and the taxpayers foot the bill.

[KRSESQ]

They're engineers. You should know engineers are always seduced by the most complicated solutions. Gives them a chance to show off.

Kevin

[Dr Mordrid]

Originally posted by KRSESQ
Spacecraft on re-entry have typically relied on the atmosphere to provide braking. I've often wondered what effect a very-low-speed re-entry would have on spacecraft heating.

I'm inclined to believe that it would take almost as much fuel to decellerate the ship to the point that atmospheric heating would be negligable, as it would to boost it to orbital velocity in the first place!

My brother is a rocket scientist (!! ). I should pose the question to him.

Kevin

It would take as much power to decelerate as to accelerate, but with the small size and simplicity of the hybrid engines and the lightweight construction they're using it could just work.

OTOH I'd never underestimate what Rutan's team can do when it comes to innovation, so suprises could still come out of their garage.

Hell...they might just decide to use a ballute for braking then dump it after they're slow enough to feather.

Dr. Mordrid

[KvHagedorn]

How's this for an impossibly complicated solution? Deploy 1000 miniature turbines which would catch the incipient atmosphere and twirl maniacally fast, generating electricity. Use the electricity to propel another turbine in the opposite direction to slow the aircraft.

[KRSESQ]

The spinning generator turbines would never provide enough energy to spin an electrically powered thruster turbine fast enough to have a signifigant effect on the spacecrafts velocity. Conservation of energy, you know.

On the other hand, just having the spinning turbines might be enough to signifigantly reduce the velocity, through drag.

Kevin