VgGalactic press release thread

[8900]

Has the shape of SS2 being finalized this time?
I think yes because there are photos showing actual hardware construction.....

[meiza]

Uh, it takes 3 hours because of the very slow ascent with the subsonic White Knight II carrier. The Spaceshiptwo flight can be counted in minutes.

The 100 km VERTICAL hop doesn't travel much horizontally (which is also intentional). Even if launched at an angle (with a lower apogee) it would only travel a few hundred kilometers. And there's the whole cocking and configuration issue. It can't fly very fast or in dense air and have much lift at the same time. Even if one quickly tried to optimize the spaceshiptwo design for maximum range with the existing powerplant, it would still suck.
New York to Chicago is 1000 km. New York to Paris is 6000 km. And Los Angeles to Tokyo across the Pacific is 9000 km. A 100 km vertical hopper is as far from these intercontinental ranges as a rowboat from a ferry.

[todd5ski]

Looks good. I hope they can get the mother ship finished and flight tested this year, maybe get as far as the drop testing/ gliding of the spaceship. I read they need to wait for the rocket engine itself until the cause of the accident is finialized.

As for the vertical hop, they would likely have to remove 4 of the 6 passenger seats for more fuel, and even strap on a couple of booster rockets on the wings. Even then they might not have enough.

[William Barton]

Interestingly, one of the idiot talking heads on Fox News was ridiculing the whole enterprise as a "flight to nowhere," and said, "If I go to all the trouble to travel in space, I want to go to a planet."

[marshallsplace]

In the BBC article Branson says "The fact that this system will have the capability to launch small payloads and satellites at low cost is hugely important,"

How does he intend to do this? does he know something we don't  

[aero313]

CuddlyRocket - 24/1/2008  5:46 AM

Branson needs to stress the environmental aspects of the design, as private space-flights are already drawing flak as polluting joy-rides for the rich.

"Environmental aspects"  Right, because burning rubber is SOOO environmentally friendly.

It's undoubtedly unfair to compare it to the STS, but it's also undoubtedly true that it will be much less polluting than the latter!

A moped is less polluting than a Mack truck.  What's your point?

Intersting that they're already thinking of different markets for the system.

Yeah, because the small satellite market has been such a moneymaker for everyone involved.  I especially like the quote about taking heat out of the planet by putting servers in orbit.  I guess it takes no energy to beam data back and forth from the ground.

[clongton]

William Barton - 24/1/2008  10:30 AM

Interestingly, one of the idiot talking heads on Fox News was ridiculing the whole enterprise as a "flight to nowhere," and said, "If I go to all the trouble to travel in space, I want to go to a planet."

Typical far right idiotic group talk. What are they going to do when their talking head goes away next January? Nobody to tell them what to think.

[todd5ski]

aero313 - 24/1/2008  10:04 AM



Yeah, because the small satellite market has been such a moneymaker for everyone involved.  

It will depend on the costs to launch from the WhiteKnight 2 mothership compared with the current costs of launching small satelites. It will also depend on the demand for small satelites.

[kevin-rf]

todd5ski - 24/1/2008  12:19 PM

aero313 - 24/1/2008  10:04 AM



Yeah, because the small satellite market has been such a moneymaker for everyone involved.  

It will depend on the costs to launch from the WhiteKnight 2 mothership compared with the current costs of launching small satelites. It will also depend on the demand for small satelites.

So you launch a peagasus from white knight 2 instead of orbitals tri-star. You save how much?

[jongoff]

Comga,

Has anyone found in the release the loaded mass of SS2?  It would be interesting to compare it to a Pegasus and the proposed t-Space Quickreach.  The release does mention using White Knight 2 for this kind of operation.

I've been curious about such things myself (particularly due to my recent interest in Air-Launched RLVs), so I did a little digging.  What I found wasn't as enlightening as I hoped, but here's what I have:

http://selenianboondocks.blogspot.com/2008/01/mass-confusion-and-white-knight-2.html

Short version:
Will Whitehorn has publicly given the payload capacity of WK2 on two different occasions (one in at a presentation at Oshkosh this year, and one to Rob Coppinger of Flight Global).  Unfortunately the two numbers don't match.  One was 30,000lb, one was ~30 tons (or tonnes)...While he may have been talking about different numbers both times (for instance maybe ~30 tonnes is the max carrying capacity, while 30klb is the carrying capacity needed for SS2), it's more likely that he just misspoke one of these times.  Alas, I fear the smaller number is the right one.  If so, it wouldn't be able to do much more than microsat launches, which as Aero313 put it, doesn't really look like that lucrative of a market.

~Jon

[JMS]

meiza - 23/1/2008  4:57 PM

Could someone knowledgeable in the composite business explain about the build process?
http://www.virgingalactic.com/pressftp/content/Photographs/SpaceShipTwo%20Construction/SpaceShipTwo%20Construction.%20wing%20assembly.jpg
What's the black material? And the yellow section?

The "black" dark grey material in the fuselage and spar structure is carbon fiber.
The yellow structure appears to be a part of the construction stand/cradle.
Have a look at this picture for a different view.
http://tinyurl.com/36bppd

[meiza]

JMS - 24/1/2008  6:22 PM

meiza - 23/1/2008  4:57 PM

Could someone knowledgeable in the composite business explain about the build process?
http://www.virgingalactic.com/pressftp/content/Photographs/SpaceShipTwo%20Construction/SpaceShipTwo%20Construction.%20wing%20assembly.jpg
What's the black material? And the yellow section?

The "black" dark grey material in the fuselage and spar structure is carbon fiber.
The yellow structure appears to be a part of the construction stand/cradle.
Have a look at this picture for a different view.
http://tinyurl.com/36bppd

I meant the mid section of the fuselage, which is not black like the rest of the vehicle. It seems the oxidizer tank should be right there.

The more I look at this, it seems like the fuselage halves are "real stuff" but the duct tape was used just to mount them together for a fit test and photo shoot. There must be a reason that these were not done in one piece. There probably wasn't a big enough autoclave for that and the winding would have been more complicated.

[JMS]

meiza - 24/1/2008  1:25 PM

I meant the mid section of the fuselage, which is not black like the rest of the vehicle.

I don't have an answer for what the different material is mid fuselage.
My best bet is that that material is overlaying the same carbon fiber structure as the rest of the fuselage, though. Perhaps for thermal reasons if that is indeed where the oxidizer tank is located.
If you zoom in on the High Res picture, that area does appear to be a raised overlay application.

I would also venture a guess that it's possible the nose section is produced in two pieces because that area might need to be accessed for routine instrumentation maintenance.
It appears from looking at the rest of the structure that SC's autoclave is large enough to produce the nose section in one piece if that were desirable.

Perhaps someone here can answer those questions definitively.

[CuddlyRocket]

Jim - 24/1/2008  12:49 PM

CuddlyRocket - 24/1/2008  5:46 AM

...but at some point in development the cost/range/time of flight equation will produce a marketable advantage over aircraft.

...I doubt it is viable for long range.  It would need to be a magnitude larger for distance

I was unclear. I was thinking of development of the series of successors to SS2.

aero313 - 24/1/2008  4:04 PM

"Environmental aspects"  Right, because burning rubber is SOOO environmentally friendly.

No, which is why he needs to address the environmental aspects, including that one!

A moped is less polluting than a Mack truck.  What's your point?

Although the average member of the public would be well aware of the difference in levels of pollution between a moped and a truck, they'll be much less aware of the difference between SS2 and the STS. All they'lll remember is that SS2 is much less polluting than the STS - which is true if Branson gets pulled up on it. (Granted it's misleading, but he'd simply express surprise that anyone wasn't aware of that.)

Yeah, because the small satellite market has been such a moneymaker for everyone involved.

If it doesn't make money, they won't do it. If it does, they will. The point is that Virgin Galactic is acting as a commercial entity, seeking to leverage its assets into any available business opportunity.

I especially like the quote about taking heat out of the planet by putting servers in orbit.  I guess it takes no energy to beam data back and forth from the ground.

Not much, a few hundred watts. Certainly a lot less than the energy used by the servers themselves. The maths is fairly trivial.

I'm not sure of the economic, as opposed to environmental, rationale. But I doubt this is actually in the business plan. It's just Branson making the company seem as green as possible (to address those environmental concerns).

[todd5ski]

kevin-rf - 24/1/2008  11:40 AM

todd5ski - 24/1/2008  12:19 PM

aero313 - 24/1/2008  10:04 AM



Yeah, because the small satellite market has been such a moneymaker for everyone involved.  

It will depend on the costs to launch from the WhiteKnight 2 mothership compared with the current costs of launching small satelites. It will also depend on the demand for small satelites.

So you launch a peagasus from white knight 2 instead of orbitals tri-star. You save how much?

No idea. It is possible they have their own rocket which may be cheaper?

[meiza]

JMS - 24/1/2008  8:08 PM

meiza - 24/1/2008  1:25 PM

I meant the mid section of the fuselage, which is not black like the rest of the vehicle.

I don't have an answer for what the different material is mid fuselage.
My best bet is that that material is overlaying the same carbon fiber structure as the rest of the fuselage, though. Perhaps for thermal reasons if that is indeed where the oxidizer tank is located.
If you zoom in on the High Res picture, that area does appear to be a raised overlay application.

I would also venture a guess that it's possible the nose section is produced in two pieces because that area might need to be accessed for routine instrumentation maintenance.
It appears from looking at the rest of the structure that SC's autoclave is large enough to produce the nose section in one piece if that were desirable.

Perhaps someone here can answer those questions definitively.

The Economist says the oxidizer tank is made of flexible glass fibre. That's what we are seeing here. Carbon fiber doesn't stretch much.
http://www.economist.com/science/displaystory.cfm?story_id=10566293

Another change in the design of the spaceship is the insertion of a flexible glass-fibre section into its composite structure. This will allow the rocket's oxidiser tank to expand when it is full. All these changes mean that when SpaceShipTwo does begin flight tests, the programme will last at least a year before paying customers can take to the skies.

[JMS]

meiza - 24/1/2008  3:31 PM

The Economist says the oxidizer tank is made of flexible glass fibre. That's what we are seeing here. Carbon fiber doesn't stretch much.
http://www.economist.com/science/displaystory.cfm?story_id=10566293

Very interesting... I wonder how it's material strength compares to the carbon fiber.

[A_M_Swallow]

JMS - 24/1/2008  10:11 PM

meiza - 24/1/2008  3:31 PM

The Economist says the oxidizer tank is made of flexible glass fibre. That's what we are seeing here. Carbon fiber doesn't stretch much.
http://www.economist.com/science/displaystory.cfm?story_id=10566293

Very interesting... I wonder how it's material strength compares to the carbon fiber.

An advert for a polyester / fibre glass
http://www.trojanproducts.co.uk/aboutus/grp/grp_more_b.htm
"The ultimate tensile strength of a freshly drawn single glass filament (diameter 9-15 microns) is about 3.5 GPa."
Claims the tensile strength of Polyester / glass roving is up to 800 MPa.

Carbon fibre data
http://en.wikipedia.org/wiki/Carbon_fiber

[meiza]

It's somewhat weaker.

I wonder though, in structural engineering having material flex discontinuities introduces point loads.

I guess they still had to make it essentially monocoque to save mass. Probably the ox tank touches the fuselage wall at every point and since its pressure varies so much it has to be able to flex and thus the wall and tank materials have to be the same to stretch the same amount.

But this means that if the fuselage is stiff CF then when you push from the nose up, the load is felt at the tank. Perhaps not. You can design the hull to flex somwhat.

[A_M_Swallow]

The big advantage of glass fibre when making the oxygen tank is that silica (SiO2) does not burn.