Space Ship Two - General Thread

[parabolicarc]

Worth having a look at the comments under this article as well as the article itself.

http://www.theguardian.com/media/greenslade/2014/jan/31/richard-branson-ipad

The article points to a lot of Bower's themes about Branson and the Virgin empire that were covered in his first biography. According to Bower, Branson leaps before he looks ("screw it, let's do it"), doesn't plan things out properly, invests as little as possible (get someone to carry most of the financial risk), and doesn't really know how to manage things properly. Bower also says he's also great at PR, creating illusions that things are better off than they are, distracting people from actual problems, and frequently lying. He's also got the attention span of a gnat.

If you take what Bower says seriously, you can begin to see patterns of many of these issues in Virgin Galactic's history. Except this isn't a new Internet app, it's a space line in a field where nobody really knows much of anything yet. So, it's a lot more difficult field to be in than running airlines, thus making proper planning, management and operations that much more important. Especially since they're not just operating brand new space vehicles but building them as well.

[Robotbeat]

This is bordering on envious FUD. Branson was and is successful. Who the heck is Bower?

[QuantumG]

I think the better question is: we knew that already.. what's your point? It works for him.

After 10 years of nothin' most people would agree Virgin Galactic is a failure, even if they do start flying anytime soon.. If you're a fan, you should be glad that Branson is so good at denying reality and keeping the media disinterested in this story.

[Star One]

Worth having a look at the comments under this article as well as the article itself.

http://www.theguardian.com/media/greenslade/2014/jan/31/richard-branson-ipad

The article points to a lot of Bower's themes about Branson and the Virgin empire that were covered in his first biography. According to Bower, Branson leaps before he looks ("screw it, let's do it"), doesn't plan things out properly, invests as little as possible (get someone to carry most of the financial risk), and doesn't really know how to manage things properly. Bower also says he's also great at PR, creating illusions that things are better off than they are, distracting people from actual problems, and frequently lying. He's also got the attention span of a gnat.

If you take what Bower says seriously, you can begin to see patterns of many of these issues in Virgin Galactic's history. Except this isn't a new Internet app, it's a space line in a field where nobody really knows much of anything yet. So, it's a lot more difficult field to be in than running airlines, thus making proper planning, management and operations that much more important. Especially since they're not just operating brand new space vehicles but building them as well.

You missed the comments in there about Mr Bower as well though?

[Vultur]

In short, Whitesides' response is far less specific than Bower's claims. Bower says Virgin Galactic lacks an engine that can get it to space (Karman line -- 100 km/62 miles). Whitesides merely points to progress in powered flights and ground tests without addressing the matter directly.

OK, what am I missing? That quote says that it has burned for "the full duration and thrust". I thought the issue was that it couldn't get into space because it couldn't burn full duration and thrust.


So did they plan for a full duration and thrust that couldn't get the vehicle into space? That seems very strange...

[baldusi]

So did they plan for a full duration and thrust that couldn't get the vehicle into space? That seems very strange...

For example, the sentence could be interpreted as that it did reached full duration and did reached full thrust. But may be not both at the same time, or couldn't keep full duration of full thrust.
But, even if it did in fact covered whole thrust*duration profile, it could be too heavy, have not enough isp or have too much vibration for the airframe to handle. Or it could be that they've found an unacceptable catastrophic failure mode. And that's just from the top of my head. Experts on the field could find more causes.

[Kabloona]

In short, Whitesides' response is far less specific than Bower's claims. Bower says Virgin Galactic lacks an engine that can get it to space (Karman line -- 100 km/62 miles). Whitesides merely points to progress in powered flights and ground tests without addressing the matter directly.

OK, what am I missing? That quote says that it has burned for "the full duration and thrust". I thought the issue was that it couldn't get into space because it couldn't burn full duration and thrust.


So did they plan for a full duration and thrust that couldn't get the vehicle into space? That seems very strange...

Parabolicarc has reported that the engine has an oscillation problem that they're trying to solve. The oscillation reportedly becomes more severe as the burn goes on.

One way to interpret this is that the engine has burned at " full duration and thrust" in ground tests but the "oscillation" (combustion instability?) becomes too severe late in the burn for the airframe and/or crew to handle, so they haven't yet been able to do a full duration firing in flight tests until the oscillation problem is solved.

Again, this is partly reporting from parabolicarc and partly pure speculation.

[parabolicarc]

In short, Whitesides' response is far less specific than Bower's claims. Bower says Virgin Galactic lacks an engine that can get it to space (Karman line -- 100 km/62 miles). Whitesides merely points to progress in powered flights and ground tests without addressing the matter directly.

OK, what am I missing? That quote says that it has burned for "the full duration and thrust". I thought the issue was that it couldn't get into space because it couldn't burn full duration and thrust.


So did they plan for a full duration and thrust that couldn't get the vehicle into space? That seems very strange...

Parabolicarc has reported that the engine has an oscillation problem that they're trying to solve. The oscillation reportedly becomes more severe as the burn goes on.

One way to interpret this is that the engine has burned at " full duration and thrust" in ground tests but the "oscillation" (maybe due to combustion instability?) becomes too severe late in the burn for the airframe and/or crew to handle, so they haven't yet been able to do a full duration firing in flight tests until the oscillation problem is solved.

Again, this is partly reporting from parabolicarc and partly pure speculation.

Yup, you mostly got it.

They've gone as far as they can go with the engine they were flying with due to oscillations and vibrations. The tests on the ground are attempting to solve that problems. However, even with a solution that allows it to fully fire, the ship can't get to the 100 km (62 mile) boundary of space they've been promising. Probably above 50 miles, which was the USAF standard in the 1960's.

[Vultur]

However, even with a solution that allows it to fully fire, the ship can't get to the 100 km (62 mile) boundary of space they've been promising

So they did plan for a "full duration and thrust" that wasn't enough? How did that happen? Did SpaceShipTwo turn out heavier than predicted?

50 miles, which was the USAF standard in the 1960's.

Did that change? I thought that was still the US (including NASA too) "astronaut wings" definition. Mike Mullane's book "Riding Rockets" mentions it, so it must have lasted at least to the Space Shuttle era.

[parabolicarc]

However, even with a solution that allows it to fully fire, the ship can't get to the 100 km (62 mile) boundary of space they've been promising

So they did plan for a "full duration and thrust" that wasn't enough? How did that happen? Did SpaceShipTwo turn out heavier than predicted?

50 miles, which was the USAF standard in the 1960's.

Did that change? I thought that was still the US (including NASA too) "astronaut wings" definition. Mike Mullane's book "Riding Rockets" mentions it, so it must have lasted at least to the Space Shuttle era.

It's what happens when you design a ship and assume you can easily scale up an engine you used on a much smaller spacecraft. Hybrids don't scale up as easily as the vehicles. This has been the basic problem going on 10 years now.

I don't know if the U.S. definition of space has changed. But, the international definition is at 100 km. And Virgin has been promising flights above 100 km up to 100 km to its customers.

[Vultur]

It's what happens when you design a ship and assume you can easily scale up an engine you used on a much smaller spacecraft. Hybrids don't scale up as easily as the vehicles. This has been the basic problem going on 10 years now.

OK, maybe I'm missing something obvious... but what you describe here doesn't sound like reaching "full thrust", it sounds like not reaching it because the engine didn't scale up like they expected. What am I not getting?

I don't know if the U.S. definition of space has changed. But, the international definition is at 100 km. And Virgin has been promising flights above 100 km up to 100 km to its customers.

Oh, certainly -- I was just surprised by the implication that that (EDIT: 50 miles, that is) was only a 1960s definition.

[parabolicarc]

It's what happens when you design a ship and assume you can easily scale up an engine you used on a much smaller spacecraft. Hybrids don't scale up as easily as the vehicles. This has been the basic problem going on 10 years now.

OK, maybe I'm missing something obvious... but what you describe here doesn't sound like reaching "full thrust", it sounds like not reaching it because the engine didn't scale up like they expected. What am I not getting?

I don't know if the U.S. definition of space has changed. But, the international definition is at 100 km. And Virgin has been promising flights above 100 km up to 100 km to its customers.

Oh, certainly -- I was just surprised by the implication that that (EDIT: 50 miles, that is) was only a 1960s definition.

Engine's not powerful enough to get them where they need to go.

[vt_hokie]

The lack of additional flight testing certainly fuels doubt.  We're already over a month into 2014 and the flight rate has yet to pick up. 

[Danderman]

OK, maybe I'm missing something obvious... but what you describe here doesn't sound like reaching "full thrust", it sounds like not reaching it because the engine didn't scale up like they expected. What am I not getting?

In this case, the burn characteristics are different for the "scaled up" engine. This means that there are significant oscillations and "chunking" compared with the smaller engines.

At least that is the official unofficial story now.

This phenomena is also manifested in LOX Kerosene engines, where going beyond 200 tons or so of thrust results in instabilities in combustion that few have solved.

[vt_hokie]

Branson still claiming service entry this year:

http://www.bloomberg.com/news/2014-02-10/branson-says-space-venture-to-fly-fare-paying-passenger-in-2014.html?cmpid=yhoo

[Robotbeat]

OK, maybe I'm missing something obvious... but what you describe here doesn't sound like reaching "full thrust", it sounds like not reaching it because the engine didn't scale up like they expected. What am I not getting?

In this case, the burn characteristics are different for the "scaled up" engine. This means that there are significant oscillations and "chunking" compared with the smaller engines.

At least that is the official unofficial story now.

This phenomena is also manifested in LOX Kerosene engines, where going beyond 200 tons or so of thrust results in instabilities in combustion that few have solved.

...but with full liquid engines, you've got a lot more knobs you can turn to solve the problem. With hybrids, the combustion chamber keeps changing on you.

[a_langwich]

Why can't they cluster SS1 hybrids?

[FutureSpaceTourist]

Branson still claiming service entry this year:

http://www.bloomberg.com/news/2014-02-10/branson-says-space-venture-to-fly-fare-paying-passenger-in-2014.html?cmpid=yhoo

He's been even more forthright: http://www.arabianbusiness.com/branson-says-his-abu-dhabi-backed-spaceships-will-one-day-rival-emirates-538299.html

“We have 300 engineers beavering away on it. We have two more test flights [and we should] go into space in three to four months time.

“If myself and my family are not in space by the end of the year, I would be very, very worried.”

So either he believes his own hype, is deliberately lying, or knows something we don't about the state of RM2 development. We'll know soon enough.

[Kabloona]

Why can't they cluster SS1 hybrids?

Because a cluster of small hybrids will have a worse mass fraction (more inert mass and less propellant) than a single large hybrid, for a given volume or mass budget for the propulsion system to fit into.

In other words, even worse performance.

[a_langwich]

He's been even more forthright: http://www.arabianbusiness.com/branson-says-his-abu-dhabi-backed-spaceships-will-one-day-rival-emirates-538299.html

“We have 300 engineers beavering away on it. We have two more test flights [and we should] go into space in three to four months time.

“If myself and my family are not in space by the end of the year, I would be very, very worried.”

So either he believes his own hype, is deliberately lying, or knows something we don't about the state of RM2 development. We'll know soon enough.

Or maybe he's being completely honest, and he's put all his chips in, and he's waited and been as disappointed as anybody on this forum, and if it doesn't pay out soon he will be very, very worried.  You would have to be foolish to be speaking in a country whose government is a major investor, and speak pessimistically about the chances that investment would pay off, don't you think?

Wasn't there a quote from Elon Musk about the fourth launch of Falcon 1, that he was pretty worried, there was a real risk to the entire rocket business idea if Falcon 1 failed again?  A quote that came well after the actual launch.

At the same time, you can judge the level of Branson's naivety?/optimism? by his prediction of 18000 mph suborbital hops within ten years, and regular passenger service within twelve.  Elon Musk levels of optimism.

The question is, what is Scaled/TSC/Galactic telling Branson?  Or maybe even, what are the engineers at Scaled telling their bosses?