Hot Rod Job For SpaceShipOne

rwven writes "MSNBC is reporting that the engine on SpaceShipOne has been modified to provide more thrust, for a longer amount of time. Mainly, the Nitrous Oxide tank has increased in size to lengthen the amount of time before the dropoff of thrust when it goes from a liquid to a gas. Also reporting is Space.com."

Comments

Green monster in space

[poptones]

Look at the cutaway - it really is a "hot rod." It appears the n2o tank is, like, six feet in diameter and right behind the crew with the engine right behind that. Yeesh, it's almost like one of those jet powered dragsters with wings - and some brave soul is gonna take it into space? I guess the next evolution will be nothing more than a good flight suit, an engine, and some carbon fiber bungee cords...

Still doesn't beat the DaVinci project

[markomarko]

Once fueled by Canadian ingenuity (and an old german rocket design), Canada's entry in the space race is now powered by faded dreams, bankruptcy, and lucky number seven!

That's right, we're powered by the online casino goldenpalace.com. One particularly enthusiastic Canadian space race supporter jumped off a diving board at the Olympics wearing a pink tutu to draw further support for the program. If only we could get goldenpalace.com to support our olympic athletes. 12 medals total. blech.

Re:Wasting precious resources

[Rei]

Yeah. It's an easy fuel/oxidizer combo, but not very scalable. The specific impulse is just too low, and the nitrous tank too heavy. I do find it funny that they described hybrid rocket engines as not being "conventional rockets" ;)

And before some of the posters here start going off on a "Specific impulse isn't everything!" line, I'll add: It's not everything, but it is *incredibly* important. And if you can't have lightweight tanks to compensate for your loss of specific impulse (which you can't with nitrous), you're not going to scale. Plus, using a carrier launch, you're not going to handle the spiralling mass increase very well.

In short, this type of design, while great for getting the X-prize (it's very simple - self pressurizing, no liquid/liquid combustion, etc), would never scale to orbit. I'd like to see a good tow-launch LOX/subcooled propane rocket; that should be scalable and yet still take advantage of air breathing power to get to altitude, and wouldn't have to deal with LH.

What everyone hopes for are some of the things that are on the horizon, that have high ISP without the various tank mass or cryogenic limitations. For example, alane (stabilized aluminum hydride) hybrid boosters, which have an ISP that even with a weaker oxidizer like H2O2, nears LOX/LH's isp, and a very high density. Everyone in rocketry would like such a panacea; however, for now, everyone has different opinions on what is the best way to go.

did they test it?

[bwy]

I wonder how much testing this new engine config has received? I don't believe it has gotten any flight time- it would have to be all ground tests.

Seems kind of concerning to me. When I finish working on my car, it sure as hell might crank up and idle okay in the garage but it is usually hit or miss the first time I take it on a road test. Obviously, these guys are better rocket scientists than I am a car mechanic, but you get the point...

What isn't said...

[RayBender]

is why they are hot-rodding the vehicle. I saw mention that the increased burn time would allow SpaceShipOne to achieve higher speed at lower altitude "where the control surfaces can bite into the air"; this tells me they are working to fix the near-disaster they had on the last flight. It sounds like they have no control authority outside the atmosphere - i.e. that whatever reaction-jet system they have isn't working well, and they are having to jury-rig a fix. Increasing the impulse of a rocket by 20% (which is what they are doing) is a significant, and risky, change. They wouldn't be doing it unless they had to.