Virgin Galatic Spaceship Two down in the Mojave.
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Private Research is Cool, But...
I'm all in favor of Sir Richard's private research projects, but... When there is significant risk to human life, perhaps he should slow down a bit and take a second look. Other than a major TOY for the very wealthy, I'm not sure that I see any real benefit in this expensive program, short of employinnng a few engineers. When a project includes significant risk to human life (rocket engines, altitudes beyond 50K ft etc.) perhaps a second and third look is necessary. What is the REAL benefit of this program - if there is one? Is it appropriate to risk human like for 1) a personal fantasy or 2) an ultimately commercial venture with no significant contribution to the flying sciences?
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What is the REAL benefit of this program - if there is one? Is it appropriate to risk human like for 1) a personal fantasy or 2) an ultimately commercial venture with no significant contribution to the flying sciences?
Therefore personally I welcome Virgin's commitment in this project. Even if at the present stage it is not much more than a funfair ride for some bored celebrities (even Lady Gaga is said to have booked a ticket), the next evolution might be a true spacegoing orbiter. Which then could also be used for science and exploration for which our taxpayers money seems to be too precious right now.
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What I find fascinating is that if this discussion were to be taking place on a marketing internet forum it would be all about virals, social optimization and conversion rates. As I said earlier, we see all this through the prism of aviation...business people such as RB see it entirely differently.
Whether or not space tourism is a reality (I'm giving that a massive thumbs down) is kinda moot to the marketing team promoting all things Virgin. They are interested in "top of the funnel" social media marketing, and further down how all that traffic converts.
What makes it even more fascinating is that RB - for the first time - might have got this one very, very wrong.
Time will tell.
Whether or not space tourism is a reality (I'm giving that a massive thumbs down) is kinda moot to the marketing team promoting all things Virgin. They are interested in "top of the funnel" social media marketing, and further down how all that traffic converts.
What makes it even more fascinating is that RB - for the first time - might have got this one very, very wrong.
Time will tell.
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No Fly
I entirely agree with your drift. I'm a strong advocate of space exploration and the pushing of human boundaries, and acknowledge the associated factors of risk to life and financial expense. But that view, for me, does not embrace Richard Branson's private experiment, and given all previous and continuing national and international space exploits, I'm unable to fathom the Virgin project's contribution. His desire to enable commercial tourism in space seems a vacuous notion, fuelled by a handful of celebrated wealthy individuals to whom the prospect of a brief excursion into a very low orbit holds an attraction: and it is only they who might have access to that flight of fancy. I find it difficult to imagine how the venture could contribute to the wider and longer term quest for practical commercial space travel on a universal basis. And the prospect of his wife, kids and a band of other laypersons being catapulted into such a hostile environment, without all the necessary fit-for-purpose skills and knowledge, must surely be a non-starter? To me, it is this that sets Sir Richard's activity way apart from most other laudable adventurous pursuits. Should it not be left to others with more appropriate acumen to pick up on previous initiatives as those alluded to by 'what next'?
I entirely agree with your drift. I'm a strong advocate of space exploration and the pushing of human boundaries, and acknowledge the associated factors of risk to life and financial expense. But that view, for me, does not embrace Richard Branson's private experiment, and given all previous and continuing national and international space exploits, I'm unable to fathom the Virgin project's contribution. His desire to enable commercial tourism in space seems a vacuous notion, fuelled by a handful of celebrated wealthy individuals to whom the prospect of a brief excursion into a very low orbit holds an attraction: and it is only they who might have access to that flight of fancy. I find it difficult to imagine how the venture could contribute to the wider and longer term quest for practical commercial space travel on a universal basis. And the prospect of his wife, kids and a band of other laypersons being catapulted into such a hostile environment, without all the necessary fit-for-purpose skills and knowledge, must surely be a non-starter? To me, it is this that sets Sir Richard's activity way apart from most other laudable adventurous pursuits. Should it not be left to others with more appropriate acumen to pick up on previous initiatives as those alluded to by 'what next'?
Last edited by jindabyne; 4th Nov 2014 at 12:34.
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I think that if the programme brings down the cost of getting to low earth orbit, it is absolutely worth while.
People kill themselves on motorcycles and in care every day, achieving nothing.
People kill themselves on motorcycles and in care every day, achieving nothing.
Jinda
You excite the public about space again, that's going to go a long way towards securing a continuing, viable future for space exploration.
A fellow pilot who never married, never had kids and lives modestly by outward appearance was contemplating a ride on Virgin's spaceship as a retirement present to himself. This is not the territory of the rich alone. You excite guys like this and good things happen, be it for a corporation or for government.
Admittedly, I've not asked if his plan remains post crash.
You excite the public about space again, that's going to go a long way towards securing a continuing, viable future for space exploration.
A fellow pilot who never married, never had kids and lives modestly by outward appearance was contemplating a ride on Virgin's spaceship as a retirement present to himself. This is not the territory of the rich alone. You excite guys like this and good things happen, be it for a corporation or for government.
Admittedly, I've not asked if his plan remains post crash.
a brief excursion into a very low orbit
For a real technology progression using this launch method a true hybrid engine would be needed - a combination jet and rocket that can transfer gradually from air-breathing to purely reactive as the air density decreases. And that is a development programme which is probably beyond even Mr Branson's deep pockets.
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The mothership launch technology has not yet overcome the technology hurdle to achieve anything better than a brief parabolic excursion beyond the atmosphere.
A manned flight into orbit would require a motership that is Mach 3+ and 100,000ft capable but even that was briefly within reach 40 years ago with the XB-70. There are people out there with ten times as much money as RB. If one of them gets infected with the space bug, who knows where we can be in ten years?
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I think we have to admire anyone who tries, even if he/she fails to push the boundaries of flight. as we say in general/commercial aviation, there is something to learn from every accident/incident. let's do the same here.. I am no expert on fuel systems etc, but surely (Shirley) there must be something we can learn here and do better next time, whether it is Virgin or someone else. I am less concerned with someone's end motives than their willingness to take risks to move forward.
what next I agree completely.
The factor between fuel-load and payload makes mothership launching much more efficient than a vertical launch even when using conventional rocket technology. For very low payloads this is actually a practical possibility.
However the one big advantage of a vertical launch is that you can design space vehicles of upwards of 3000 tons (Saturn V). Realistically though a mothership is not going to be able to carry a craft weighing more than a few tens of tons.
So either the mothership or the rocket engine needs a huge technology advance.
The factor between fuel-load and payload makes mothership launching much more efficient than a vertical launch even when using conventional rocket technology. For very low payloads this is actually a practical possibility.
However the one big advantage of a vertical launch is that you can design space vehicles of upwards of 3000 tons (Saturn V). Realistically though a mothership is not going to be able to carry a craft weighing more than a few tens of tons.
So either the mothership or the rocket engine needs a huge technology advance.
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Escape System
Can someone explain how the pilot got out of this 'plane'...I understand the parachute bit but what happens before? Were the punters also to have parachutes??
"Even if at the present stage it is not much more than a funfair ride for some bored celebrities (even Lady Gaga is said to have booked a ticket)"
Also not forgetting IIRC that NASA had (maybe allegedly) booked a few flights for research projects (& future astronaut training?)
Also not forgetting IIRC that NASA had (maybe allegedly) booked a few flights for research projects (& future astronaut training?)
......... Other than a major TOY for the very wealthy, I'm not sure that I see any real benefit in this expensive program, short of employinnng a few engineers. When a project includes significant risk to human life (rocket engines, altitudes beyond 50K ft etc.) perhaps a second and third look is necessary. What is the REAL benefit of this program - if there is one? Is it appropriate to risk human like for 1) a personal fantasy or 2) an ultimately commercial venture with no significant contribution to the flying sciences?
Of course, you have to assume that the participant is fully aware of the risks. I would bet that Leonardo di Caprio, for example, would be VERY unlikely to have ever used his space ride ticket once they got down to the nitty-gritty of explaining how dangerous space travel really is.
Unfortunately, I don't think Christa McAuliffe fully understood what risk she was facing when she met her end and probably expected something like a bus ride. Although the statistics have improved lately, for a long while nearly 10% of the Americans who wanted to fly in space died while practicing their chosen profession, or in Ms. McAuliffe's case, her school science project.
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Time line released by NTSB
Release from WhiteKnightTwo at 10:07:19 (local time).
10:07:21 Engine Start
10:07:29 Speed 0.94 Mach
10:07:31 Speed 1.02 Mach
At that point the co-pilot moved the feather control from locked to unlocked.
A second step, to engage the feather, was not taken.
10:07:34 The feather began to deploy, telemetry data stops.
The flight plan indicated the feather should be unlocked at Mach 1.4.
10:07:21 Engine Start
10:07:29 Speed 0.94 Mach
10:07:31 Speed 1.02 Mach
At that point the co-pilot moved the feather control from locked to unlocked.
A second step, to engage the feather, was not taken.
10:07:34 The feather began to deploy, telemetry data stops.
The flight plan indicated the feather should be unlocked at Mach 1.4.
Last edited by Niner Lima Charlie; 5th Nov 2014 at 14:02.
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Deptrai quoted: "Two main pneumatic 625-psi actuators with a 9.5-in bore and 31-in stroke, change the position of the feather ..."
625 psi (max?) over an area corresponding to 9.5" diameter gives a force of over 40,000 lb possible on each actuator. Quite a bit, which would seem to make it nearly irreversible, almost as good as a hydraulically operated screw jack on an airliner.
But is there pressure already applied to both sides of the piston before the Feather handle is actuated? From the results, maybe not.
Perhaps the feathering cylinders only receive pressure when the feathering handle is turned to open valves -- Rather than having both sides of the cylinder pressurized. That would be perhaps slightly more complex, more like some always-active hydraulic system. Rather than just "start adding a shot of air when needed to the Feather side". (Even then they would need to be able to let the pressure bleed down and pressurize the other side of the piston to defeather later.)
As for forces on the tail, the stabilizers themselves might well have a down force on them, especially as a typical airplane tends to have a mach tuck due to rearwards movement of the center of pressure in the transonic range (and loss of effectiveness of a conventional elevator, not a factor here).
However, the feathering mechanism also includes the aft end of the wings which will have some lift on them. While I'm a little surprised at it, the results suggest the net forces were to flip the tail up as soon as the locks were removed.
In conclusion, it sound like the feathering system may be set up assuming that there would be very little aerodynamic force once the locks were withdrawn, without the system being pressurized before selecting Unlock, and thus unable to oppose any significant aerodynamic forces.
That would suggest a design which, while entirely effective, lacked some safety redundancy that could have been added probably without too much trouble. Turn that one handle too soon and boom, you pitch up with massive up elevator and loss of lift from the aft end of the tail, you swap ends and disintegrate.
But one would like to know more about the feathering system to better understand whether this speculation is correct or not.
(Edit: And I don't know what kind of leverage the tail might have on the actuator around a pivot point, which also affects to what degree the tail can try to back drive the piston even if pressurized)
625 psi (max?) over an area corresponding to 9.5" diameter gives a force of over 40,000 lb possible on each actuator. Quite a bit, which would seem to make it nearly irreversible, almost as good as a hydraulically operated screw jack on an airliner.
But is there pressure already applied to both sides of the piston before the Feather handle is actuated? From the results, maybe not.
Perhaps the feathering cylinders only receive pressure when the feathering handle is turned to open valves -- Rather than having both sides of the cylinder pressurized. That would be perhaps slightly more complex, more like some always-active hydraulic system. Rather than just "start adding a shot of air when needed to the Feather side". (Even then they would need to be able to let the pressure bleed down and pressurize the other side of the piston to defeather later.)
As for forces on the tail, the stabilizers themselves might well have a down force on them, especially as a typical airplane tends to have a mach tuck due to rearwards movement of the center of pressure in the transonic range (and loss of effectiveness of a conventional elevator, not a factor here).
However, the feathering mechanism also includes the aft end of the wings which will have some lift on them. While I'm a little surprised at it, the results suggest the net forces were to flip the tail up as soon as the locks were removed.
In conclusion, it sound like the feathering system may be set up assuming that there would be very little aerodynamic force once the locks were withdrawn, without the system being pressurized before selecting Unlock, and thus unable to oppose any significant aerodynamic forces.
That would suggest a design which, while entirely effective, lacked some safety redundancy that could have been added probably without too much trouble. Turn that one handle too soon and boom, you pitch up with massive up elevator and loss of lift from the aft end of the tail, you swap ends and disintegrate.
But one would like to know more about the feathering system to better understand whether this speculation is correct or not.
(Edit: And I don't know what kind of leverage the tail might have on the actuator around a pivot point, which also affects to what degree the tail can try to back drive the piston even if pressurized)
Last edited by pchapman; 4th Nov 2014 at 15:31. Reason: typo
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The flight plan indicated the feather should be unlocked at Mach 1.04
There will undoubtedly be some human-performance analysis to see if one of the pilots saw 1.04 and got it confused with 1.40. However the latest NTSB briefing seems to indicate that the unlock happened prior to reaching Mach 1.02.
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Certification
This has been raised a couple of times here but to my knowledge no-one has explained what certification 'ticket' they are working towards and who will decide when the beast is fit to carry commercial passengers.
It can't be Sir R who decides just because one day he feels ready to risk himself and his family.
Concorde required lots of new rules to be complied with, yet FAA or FARs hardly get a mention in this story.
It can't be Sir R who decides just because one day he feels ready to risk himself and his family.
Concorde required lots of new rules to be complied with, yet FAA or FARs hardly get a mention in this story.
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So the investigators are saying the test pilots caused the crash by doing something they shouldn't, and understandably that is being received with scepticism on here. But is it possible the feathering deployment was a test to make sure the interlocks/software etc would prevent it?
Take a completely different situation, try to raise the landing gear while you are on the ground and interlocks/pressure switches will prevent it - but at some point someone has tried to do it, to make sure it doesn't happen.
The only way to test these potentially dangerous side effects is to test them and make sure the systems prevent you doing it - and if they don't then you are in trouble.
Take a completely different situation, try to raise the landing gear while you are on the ground and interlocks/pressure switches will prevent it - but at some point someone has tried to do it, to make sure it doesn't happen.
The only way to test these potentially dangerous side effects is to test them and make sure the systems prevent you doing it - and if they don't then you are in trouble.
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Yes, and it wasn't pretty