Launch News Blue Origin Suborbital Test [FAILURE]

[Thunder Chicken]

Blue Origin had to destroy its vehicle during a suborbital test flight at 45,000 ft (13,700 m) and Mach 1.2:

http://www.blueorigin.com/letter.htm

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My two cents: It sounds to me that the control system got overwhelmed at maximum dynamic pressure. Seeing how blunt this vehicle is I wouldn't be surprised to find that the air flow was separating off the nose cone, rendering the stabilizing fins ineffective.

The whole tail-sitter concept is pretty interesting though, and apparently they have had some successful hop flights. I do have to say though that I would worry about the whole thing toppling over on landing during a wind event.

They do score bonus points for having a great logo and motto:

Gradatim Ferociter ~ "Small Steps with Fierce Determination"
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[ky]

Well, all the air builds up on the nose cone, creating drag which slows it down, rendering the guidance system pretty much useless.

 

[Hlynkacg]

Well, all the air builds up on the nose cone, creating drag which slows it down, rendering the guidance system pretty much useless.

???

Speed and the acompanying Atmospheric drag should not be a guidance issue unless there is an associated aerodynamic intabilty.

Blunt bodies tend to be stable, a more likely problem is, (as TC hypothesiszed) that at Max-Q the craft did not have enough control authority overcome it's own moment of inertia.

 

[ky]

If as you said, a blunt body tends to be stable, why do most of the rockets I see are streamlined?

 

[Hlynkacg]

The short answer is that most designs are expendable and as such they are optimised for the first 2 minutes of flight. For an expendable launcher initial dV savings are a far greater concern than aerodynamic stability. (If it gets up who cares how it comes down, notice that re-entry capsules are NOT pointy)

If you plan to re-use your booster, structural integrity and stability become much more important.

The long answer would be a physics paper.

Convair Nexus Addon

 

[Notebook]

Shame, always liked this vehicle. Hopefully they'll get it going.

N.

 

[boogabooga]

Blunt Bodies-> Less sever aerodynamic heating. Used in the past when you want to travel through the atmosphere at very high speed and not burn yourself to a crisp. (Think Thor IRBM, Apollo command module, space shuttle orbiter). If these guys expect to launch this thing into space and get it back in one piece, then that is probably why they went with a blunt body.

Pointed conical, sharp, etc. bodies-> minimizes aerodynamic drag and maximizes stagnation pressure recovery at speeds greater than about Mach 1. Used when you want to efficiently travel through the atmosphere and aren't worried about the heating for whatever reason. Perhaps you aren't going fast enough for heating to be a problem with conventional materials. Perhaps you won't be in the atmosphere for very long. Perhaps you are going to be going very fast but have great materials to deal with it.

I would think that stability is always a concern. Efficiency on the other hand, could be compromised. While it appears that this craft was not stable, there are examples of "stable" vehicles using both blunt and pointy leading surfaces, so I doubt if that factor alone explains the problem.

 

[Tacolev]

Shortest short answer: Rockets are streamlined for going up capsules are blunt for coming down.

 

[boogabooga]

But this thing is meant to do both.

 

[Zeehond]

But this thing is meant to do both.

From what I read, this thing is meant to do suborbital hops.

We can't say what the problem was, as these guys are pretty secretive. It will most likely not be an obvious problem, as they are rumored to have a pretty decent team.

 

[Hlynkacg]

Remember that stability is not the same thing as efficiency or drag. Afterall, the most aerodynamically stable shape possible would be a homogeneous sphere.

As others have stated above, a vessels's body-shape is a compromise between multiple competing concerns.

 

[orb]

Aviation Week: Blue Origin Vehicle Loss Shows Its Progress:

The inflight failure of Blue Origin’s second test vehicle isn’t necessarily a failure of the secretive company’s efforts to begin launching scientists and space tourists on a reusable suborbital rocket, and won’t affect NASA’s plans to use private launchers to get cargo and crew to the International Space Station (ISS)

The company’s VTVL test vehicle reached 45,000 ft. and Mach 1.2 before “flight instability” triggered the range safety system and shut down the vehicle’s engines, letting it crash in the desert near its West Texas test site. Based on an FAA notice to airmen for the area, the high-altitude test occurred on Aug. 24.

Jeff Bezos, the Amazon.com founder who is bankrolling the Kent, Wash.-based startup, posted a notice on the Blue Origin website Sept. 2 vowing to continue working. The team had already flown a short “hop” with the vehicle that crashed, Bezos says. The parameters of its second and final flight demonstrate that the new vehicle was a significant step forward over the initial “New Shepard” craft that flew on Nov. 13, 2006.

The crash was “not the outcome any of us wanted, but we’re signed up for this to be hard, and the Blue Origin team is doing an outstanding job,” Bezos wrote after the Wall Street Journal broke the story of the crash. “We’re already working on our next development vehicle.”

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