Space Ship Two - General Thread

[Danderman]

Well at least you have to admit, that especially SpaceX had a big mouth up until now delivered nothing really substantial. If they succeed i will cheer them as well, but from todays standpoint.....

The same could have been said for the Boeing 787, which was over 3 years late.

Does this mean that you think the government should design and build all aircraft?

Not at all. All i wanted to say is that commercial space does not better up until now then goverment agencies. But many people act as if it would.

Again, condemning an economic system by virtue of a couple of years of observing is not appropriate; moreso when  you personally use that same economic system every day of your life.

90% of all new restaurants fail within 6 months of opening. Does this mean that commercial restaurants are a bad idea, and that we should all eat at government eateries?

Virgin Galactic is going slower than we hoped, but they are attempting something that no one has ever done - develop an operational space transportation system. Not an experimental system like Shuttle or even Soyuz, that flies occasionally; VG plans to fly a lot, which puts them closer to airliners than rockets.

[Olaf]

Some news
http://www.parabolicarc.com/2012/02/06/whitesides-powered-spaceshiptwo-flights-planned-for-summer/

[ChefPat]

Some news
http://www.parabolicarc.com/2012/02/06/whitesides-powered-spaceshiptwo-flights-planned-for-summer/

What's with the Smiley Face.

[Garrett]

Some news
http://www.parabolicarc.com/2012/02/06/whitesides-powered-spaceshiptwo-flights-planned-for-summer/

From that article

"... and then [will] try and start powered flight over the summer,” Whitesides told SPACE.com.

Of course, summer doesn't finish until September 21st, so that could mean at least another 7 months of waiting. 

[Moe Grills]

Some news
http://www.parabolicarc.com/2012/02/06/whitesides-powered-spaceshiptwo-flights-planned-for-summer/

From that article

"... and then [will] try and start powered flight over the summer,” Whitesides told SPACE.com.

Of course, summer doesn't finish until September 21st, so that could mean at least another 7 months of waiting. 

In this business, you have to be patient.
Don't even think of getting into the business of space if you have no patience.
BTW,
It's better than the 'news' I read that said the first powered-flight would occur near the end of the year or start of next year.

I'm reviving my prediction: SS2 goes supersonic on October, 14, 2012.
October, 14th.  Date sound familiar?

[astrobrian]

I'm reviving my prediction: SS2 goes supersonic on October, 14, 2012.
October, 14th.  Date sound familiar?

If memory serves, that was SS1s first suborbital flight date

[JMS]

The X-1 first flew beyond mach 1 on october 14 1947.

[Moe Grills]

The X-1 first flew beyond mach 1 on october 14 1947.

Exactly! It's the  65th anniversary of Chuck Yeager's flight this year.

Imagine! What he accomplished led to the today's military jets, X-15, Concorde, even the Space Shuttle.
Sorry, off topic.

But to get back on topic, I am concerned that what happened to Concorde may happen to Space Ship Two...eventually.
As you know, Concorde flew 1,000's of well-heeled passengers for over 20 years, then Concorde went under due to tragedy.

The SS2 could end up flying 1,000's of well-heeled passengers over a period of 20 years, then tragedy could ground it too.

[simonbp]

Some news
http://www.parabolicarc.com/2012/02/06/whitesides-powered-spaceshiptwo-flights-planned-for-summer/

What's with the Smiley Face.

More to the point, why are WK2's gear down during the drop?

[Namechange User]

More to the point, why are WK2's gear down during the drop?

My guess is a flight-envolope verification test to make sure if the gear did not retract for some reason that the air-flow did not disrupt the expected separation profile.

[Jason1701]

More to the point, why are WK2's gear down during the drop?

My guess is a flight-envolope verification test to make sure if the gear did not retract for some reason that the air-flow did not disrupt the expected separation profile.

The first few drop tests were done soon after WK2 had a gear extension problem, so they left the gear down for the whole flight. You can see it at the Spaceport runway dedication too.

[Garrett]

Tweet from VG

Our contractor team test-fired RocketMotorTwo, SS2's hybrid rocket motor, again on Tues. It went well! Details: http://bit.ly/qN1hwn
March 15th, 2012

The link points to the Scaled RM2 updates page. Here is the latest update:

Fire: 09
Date: 13 March 12

Objectives:
Ninth full scale flight design RM2 hot-fire.
Continued evaluation of all systems and components:
- Pressurization
- Valve/Injector
- Fuel formulation and geometry
- Nozzle
- Structure
- Performance

Results:
All objectives completed. Performed full 45 second hot fire as planned. Duration of burn chosen to allow examination of internal core geometry.

To understand what they mean by "examination of internal core geometry", I turned to Google, which inevitably led to Wikipedia:
http://en.wikipedia.org/wiki/Solid-fuel_rocket

Solid rocket fuel deflagrates from the surface of exposed propellant in the combustion chamber. In this fashion, the geometry of the propellant inside the rocket motor plays an important role in the overall motor performance. As the surface of the propellant burns, the shape evolves (a subject of study in internal ballistics), most often changing the propellant surface area exposed to the combustion gases.

I'm trying to understand, in my non-rocket specialist mind (but still with my professional engineering/scientist mind), why a rocket company is performing such a fundamental test so late in the program. Surely this is the type of thing they test from the start and compare with computer models?

Whatever the reason, this appears to tell us that the rocket is still not ready for installation into SS2. I'd love to be wrong about that.

[Robotbeat]

Tweet from VG

Our contractor team test-fired RocketMotorTwo, SS2's hybrid rocket motor, again on Tues. It went well! Details: http://bit.ly/qN1hwn
March 15th, 2012

The link points to the Scaled RM2 updates page. Here is the latest update:

Fire: 09
Date: 13 March 12

Objectives:
Ninth full scale flight design RM2 hot-fire.
Continued evaluation of all systems and components:
- Pressurization
- Valve/Injector
- Fuel formulation and geometry
- Nozzle
- Structure
- Performance

Results:
All objectives completed. Performed full 45 second hot fire as planned. Duration of burn chosen to allow examination of internal core geometry.

To understand what they mean by "examination of internal core geometry", I turned to Google, which inevitably led to Wikipedia:
http://en.wikipedia.org/wiki/Solid-fuel_rocket

Solid rocket fuel deflagrates from the surface of exposed propellant in the combustion chamber. In this fashion, the geometry of the propellant inside the rocket motor plays an important role in the overall motor performance. As the surface of the propellant burns, the shape evolves (a subject of study in internal ballistics), most often changing the propellant surface area exposed to the combustion gases.

I'm trying to understand, in my non-rocket specialist mind (but still with my professional engineering/scientist mind), why a rocket company is performing such a fundamental test so late in the program. Surely this is the type of thing they test from the start and compare with computer models?

Whatever the reason, this appears to tell us that the rocket is still not ready for installation into SS2. I'd love to be wrong about that.

Whether or not it's behind schedule, you need to examine things like this throughout a test program, not just at the beginning.

[Garrett]

Whether or not it's behind schedule, you need to examine things like this throughout a test program, not just at the beginning.

But isn't this a fundamental study they seem to be carrying out, i.e. something one would expect SNC to have known a lot about before they designed/built the rocket.
Also, aren't we supposed to be at the end of the test program? They've been performing hot-fires for almost three years now.

It just seems like a shame for both WK2 and SS2 to be more or less lying idle while waiting for RM2 to finally get the go.

[FuseUpHereAlone]

I suppose there must be some uncertainty as to how the oxidizer flows over the solid fuel grain.  CFD analysis can only go so far when dealing with combustion, especially if the boundary condition (solid fuel wall) erodes throughout the hot fire.  So it makes a whole lot of sense to me to sample what the fuel grain profile at various stages of the burn.

[Garrett]

I suppose there must be some uncertainty as to how the oxidizer flows over the solid fuel grain.  CFD analysis can only go so far when dealing with combustion, especially if the boundary condition (solid fuel wall) erodes throughout the hot fire.  So it makes a whole lot of sense to me to sample what the fuel grain profile at various stages of the burn.

I don't disagree that it makes sense to sample the internal geometry at various stages of the burn. I'm just surprised that they're still doing tests of this type this late in the program. But I have no expertise whatsoever with solid rocket motors to claim anything other than my personal surprise.

In the domain of science I work in, such sampling is usually only done during the fundamental research and development stage. It's not something one would do on a product just before delivery to a customer.

They could of course be simply making one final attempt to optimize the motor, to try to squeeze every last drop of power out of it. It might add several extra seconds to the weightless experience, which doesn't appear like it's gonna be that long (hints from VG of 4 minutes max).

[QuantumG]

I asked Mark Sirangelo similar questions on The Space Show. http://www.thespaceshow.com/guest.asp?q=977

He shut me down pretty quickly with a simple answer that I didn't expect: Sierra Nevada considers this motor to be "mature" already. There's not in a "test program" on this motor at all.

simply making one final attempt to optimize the motor

It seems that is the way they see it.. they're merely improving on a mature design.

[Jason1701]

I asked Mark Sirangelo similar questions on The Space Show. http://www.thespaceshow.com/guest.asp?q=977

He shut me down pretty quickly with a simple answer that I didn't expect: Sierra Nevada considers this motor to be "mature" already. There's not in a "test program" on this motor at all.

simply making one final attempt to optimize the motor

It seems that is the way they see it.. they're merely improving on a mature design.

Did you ask him about combustion stability?

[QuantumG]

Did you ask him about combustion stability?

The next caller did. His reply was something akin to "we're happy with it, but we're trying to iron out the last of it anyway" (not a quote, my memory may be fuzzy).

[AlanRex54]

Tweet from VG

Our contractor team test-fired RocketMotorTwo, SS2's hybrid rocket motor, again on Tues. It went well! Details: http://bit.ly/qN1hwn
March 15th, 2012

The link points to the Scaled RM2 updates page. Here is the latest update:

Fire: 09
Date: 13 March 12

Objectives:
Ninth full scale flight design RM2 hot-fire.
Continued evaluation of all systems and components:
- Pressurization
- Valve/Injector
- Fuel formulation and geometry
- Nozzle
- Structure
- Performance

Results:
All objectives completed. Performed full 45 second hot fire as planned. Duration of burn chosen to allow examination of internal core geometry.

To understand what they mean by "examination of internal core geometry", I turned to Google, which inevitably led to Wikipedia:
http://en.wikipedia.org/wiki/Solid-fuel_rocket

Solid rocket fuel deflagrates from the surface of exposed propellant in the combustion chamber. In this fashion, the geometry of the propellant inside the rocket motor plays an important role in the overall motor performance. As the surface of the propellant burns, the shape evolves (a subject of study in internal ballistics), most often changing the propellant surface area exposed to the combustion gases.

I'm trying to understand, in my non-rocket specialist mind (but still with my professional engineering/scientist mind), why a rocket company is performing such a fundamental test so late in the program. Surely this is the type of thing they test from the start and compare with computer models?

Whatever the reason, this appears to tell us that the rocket is still not ready for installation into SS2. I'd love to be wrong about that.

The report didn't actually say if the motor was in SS2 or not.  I thought there had already been a picture with a caption that the moter was at Scaled and was in the process of being placed into SS2?