Virgin Galatic Spaceship Two down in the Mojave.
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"We were doing a test that we believed was completely safe. ... We don't know why it exploded," said Rutan
I was just wondering if "space tourism" is worth the (apparently) inevitable loss of lives. Maybe it's the wrong question to ask, and anyway I'm not qualified to have an opinion; the professional test pilots and engineers involved can judge the risks better than anyone else. They are pushing the envelope of aerospace technology, and I really do admire them for that.
Last edited by deptrai; 2nd Nov 2014 at 09:02.
It is much more than just and only "space tourism", it is whole new
industry. Scaled and VG are just bit more exposed, because of
red carpet in front of hangars... The life/industry is going on...
Here ->
industry. Scaled and VG are just bit more exposed, because of
red carpet in front of hangars... The life/industry is going on...
Here ->
Oxiser tank to rocket motor connection failure?
Trying to get something from the pictures.
From the NTSB B-Roll video 0:18 top of tank, 0:34 bottom of tank/interface (though hard to see) and 2:47 rocket motor(?) which appears intact at least the front end, one might think of a connection failure between the tank and motor, rather than an "explosion". Or the invisible motor bottom end burried in the sand may hide a failure that provoked the tank-motor separation. In both cases an immediate vehicle break-up would be a likely next effect.
The motor will have been subjected to ground tests multiple times, however it´s behaviour integrated in the vehicle in flight conditions cannot be investigated beforehand other than by modelling, and unexpected effects may be revealed in actual flight. Propulsion dynamics coupled with aero-elasticity? One can only guess at this stage.
Perhaps someone can fill-in at some point about state of tank-bottom and motor-bottom/throat/nozzle?
Just my 2 pence.
From the NTSB B-Roll video 0:18 top of tank, 0:34 bottom of tank/interface (though hard to see) and 2:47 rocket motor(?) which appears intact at least the front end, one might think of a connection failure between the tank and motor, rather than an "explosion". Or the invisible motor bottom end burried in the sand may hide a failure that provoked the tank-motor separation. In both cases an immediate vehicle break-up would be a likely next effect.
The motor will have been subjected to ground tests multiple times, however it´s behaviour integrated in the vehicle in flight conditions cannot be investigated beforehand other than by modelling, and unexpected effects may be revealed in actual flight. Propulsion dynamics coupled with aero-elasticity? One can only guess at this stage.
Perhaps someone can fill-in at some point about state of tank-bottom and motor-bottom/throat/nozzle?
Just my 2 pence.
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Huge fan of space flight development since a kid in the 60's. Thru some little reading and internet chasing, it appears ......... Who knows how accurate....
2014 change of engine
In May 2014, Virgin Galactic announced a change to the hybrid engine to be used in SpaceShipTwo, and took the development effort in-house, terminating the contract with Sierra Nevada and all development on the first-generation rocket engine.
Rather than use rubber-based HTPB in the solid portion of the hybrid rocket motor—which had experienced serious engine stability issues on firings longer than approximately 20 seconds—the Virgin Galactic-developed SS2 hybrid rocket engine would now use thermoplastic polyamide (i.e., nylon) as the solid fuel component of the propellant. The plastic fuel was projected to have better performance (by several unspecified measures) and was expected to allow SpaceShipTwo to make flights to a higher altitude.
As of May 2014, the new engine formulation had already completed full-duration burns of over 60 seconds in ground tests on an engine test stand. However, four additional ground tests of the polyamide-fueled engine are anticipated before the SpaceShipTwo flight test could resume with the new-fuel rocket motor.
PF04 malfunction
On 31 October 2014, the new polyamide engine fuel formulation was used in flight for the first time in the PF04 powered test flight of SpaceShipTwo. At 10:12am PDT, VSS Enterprise suffered an engine malfunction, and subsequently broke up in mid-flight. The inflight mishap resulted in the death of one test pilot and severe injuries to the other test pilot, and a total loss of the vehicle.
.............
Appears it may have been the first inflight ignition of the new propellant combination in the motor
2014 change of engine
In May 2014, Virgin Galactic announced a change to the hybrid engine to be used in SpaceShipTwo, and took the development effort in-house, terminating the contract with Sierra Nevada and all development on the first-generation rocket engine.
Rather than use rubber-based HTPB in the solid portion of the hybrid rocket motor—which had experienced serious engine stability issues on firings longer than approximately 20 seconds—the Virgin Galactic-developed SS2 hybrid rocket engine would now use thermoplastic polyamide (i.e., nylon) as the solid fuel component of the propellant. The plastic fuel was projected to have better performance (by several unspecified measures) and was expected to allow SpaceShipTwo to make flights to a higher altitude.
As of May 2014, the new engine formulation had already completed full-duration burns of over 60 seconds in ground tests on an engine test stand. However, four additional ground tests of the polyamide-fueled engine are anticipated before the SpaceShipTwo flight test could resume with the new-fuel rocket motor.
PF04 malfunction
On 31 October 2014, the new polyamide engine fuel formulation was used in flight for the first time in the PF04 powered test flight of SpaceShipTwo. At 10:12am PDT, VSS Enterprise suffered an engine malfunction, and subsequently broke up in mid-flight. The inflight mishap resulted in the death of one test pilot and severe injuries to the other test pilot, and a total loss of the vehicle.
.............
Appears it may have been the first inflight ignition of the new propellant combination in the motor
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Following up on the crash site photos. The large rounded black item has been referred to by some as a portion of the oxidizer tank. After discovering some photos of the composite section assembly I actually think what we're looking at is the aft bulkhead of the pressure hull.
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radix.
Unless the surges were so severe that it had an effect on other parts of the motor causing the flame to reach the liquid fuel it doesn't explain what happened.
Unless the surges were so severe that it had an effect on other parts of the motor causing the flame to reach the liquid fuel it doesn't explain what happened.
It is not at all clear that this is the problem here, but surging was mentioned as a problem on previous flights, even when using the rubber fuel.
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The assembly photo above shows that pilot ejection seats are not an option in this design. Nor would I expect them to be, passengers are not happy being left behind.
Some mention in press that pilots rode ejection seats down, worst reports are in the Daily Mail. They have a graphic which shows ejection pods from a B-58 Hustler no less .... quite bizarre reporting.
Irregardless, to survive that accident from that altitude in freefall means serious planning was put into the bailout bottle system, whatever they used.
Some mention in press that pilots rode ejection seats down, worst reports are in the Daily Mail. They have a graphic which shows ejection pods from a B-58 Hustler no less .... quite bizarre reporting.
Irregardless, to survive that accident from that altitude in freefall means serious planning was put into the bailout bottle system, whatever they used.
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I was just wondering if "space tourism" is worth the (apparently) inevitable loss of lives.
We need the remind ourselves that in some part we are where we are in aviation safety, off the backs of dead people, many of them innocent. We make mistakes, we learn. (well sometimes we learn)
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A hundred years ago the US began it's airmail service. 31 out of the first 40 pilots who were hired to fly airmail died in a plane crash. Progress has a price and this world owes a lot to those brave adventurers who are willing pay that price.
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Sunday PM NTSB briefing:
- N2O oxidizer tank found intact
- SpaceShipTwo appear to have had an "uncommanded feather"
- In order to feather, normal procedures involve two steps: 1) co-pilot moves "feather lock" lever to unlock; 2) a second feather lever must then be operated to actually initiate the feather
- Procedure calls for "feather lock" lever to remain in "locked" position until Mach 1.4 due to aerodynamic forces. However the "copilot" unlocked the lever at around Mach 1.0. (reason unknown).
- The second lever was never operated. An "uncommanded feather" took place approximately 2 seconds after the feather unlock.
- After the uncommanded feather, SpaceShipTwo subsequently disintegrated.
- No determination of cause at this point
- N2O oxidizer tank found intact
- SpaceShipTwo appear to have had an "uncommanded feather"
- In order to feather, normal procedures involve two steps: 1) co-pilot moves "feather lock" lever to unlock; 2) a second feather lever must then be operated to actually initiate the feather
- Procedure calls for "feather lock" lever to remain in "locked" position until Mach 1.4 due to aerodynamic forces. However the "copilot" unlocked the lever at around Mach 1.0. (reason unknown).
- The second lever was never operated. An "uncommanded feather" took place approximately 2 seconds after the feather unlock.
- After the uncommanded feather, SpaceShipTwo subsequently disintegrated.
- No determination of cause at this point
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How it happened- from chair NTSB - WSJ
SpaceShipTwo's unique tail section, which can "feather" at an angle to help the Virgin Galactic spacecraft make a safe descent, unfurled as it was ascending during the flight that ended in a fatal breakup Friday and without being ordered to do so, federal investigators said Sunday night.
The "feathering" mechanism isn't supposed to be unlocked until the spacecraft reaches 1.4 times the speed of sound, Christopher Hart, the NTSB's acting chairman, said at a news conference. But on the flight that crashed Friday, co-pilot Michael Alsbury moved the mechanism's lock-unlock lever into the unlocked position earlier, at just slightly above Mach 1, Hart said.
The "feathering" procedure is supposed to require two separate steps to engage: First, a pilot must unlock the feather parameter; then he or she must move a feather handle into position. SpaceShipTwo's feather mechanism began moving almost immediately — even though neither pilot took that second step,
The "feathering" mechanism isn't supposed to be unlocked until the spacecraft reaches 1.4 times the speed of sound, Christopher Hart, the NTSB's acting chairman, said at a news conference. But on the flight that crashed Friday, co-pilot Michael Alsbury moved the mechanism's lock-unlock lever into the unlocked position earlier, at just slightly above Mach 1, Hart said.
The "feathering" procedure is supposed to require two separate steps to engage: First, a pilot must unlock the feather parameter; then he or she must move a feather handle into position. SpaceShipTwo's feather mechanism began moving almost immediately — even though neither pilot took that second step,
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Were these Pilots qualified for the job of Test Pilot? Seems worrying to me that they were on the leading edge of such a flight test program without much more than being the right PR men. Regardless of cause, is it correct that they were both amateur "Test Pilots"?
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Regardless of cause, is it correct that they were both amateur "Test Pilots"?
RIP the pilot and thoughts with his family.
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Were these Pilots qualified for the job of Test Pilot? Seems worrying to me that they were on the leading edge of such a flight test program without much more than being the right PR men. Regardless of cause, is it correct that they were both amateur "Test Pilots"?
Seems that Pilot error is now being touted in the Media despite in the next breath telling us that it will take many months to find the actual cause.
Why drip feed information which may or may not have relevance?
Of course it may help to retain those investors who have put money into this project as well as provide some reassurance to those who have paid hundreds of thousands to fly on Virgin Galactic.
Call me a cynic but releasing any information at this stage is just wrong and smacks of project damage control.
Why drip feed information which may or may not have relevance?
Of course it may help to retain those investors who have put money into this project as well as provide some reassurance to those who have paid hundreds of thousands to fly on Virgin Galactic.
Call me a cynic but releasing any information at this stage is just wrong and smacks of project damage control.
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Thanks Peekay4. That explains why the ship was upside down and going backwards in the photos. It pitched end over end, ripping off the tail feathers and the delta wings. Those parts and a glowing piece, presumably the motor, are visible. The lighter pieces are trailing the fuselage, and the heavier motor is some distance ahead.
BTW, I looked up the term "fuel grain" as used in rocket motors. It refers to the entire cylinder-shaped mass of solid fuel.
BTW, I looked up the term "fuel grain" as used in rocket motors. It refers to the entire cylinder-shaped mass of solid fuel.
