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Space Ship Two Crash

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Re: Space Ship Two Crash

Unread postby Sixstrings » Mon 03 Nov 2014, 07:38:55

Tanada wrote:In a normal flight the tail section 'feathers' meaning it fold upward 90 degrees to act as a giant air brake for the craft to control descent speed. Apparently the copilot hit the unlock switch by mistake earlier in the flight, after that all it takes is turbulence to move the tail out of line. That happened when the craft was at Mach 1.4, causing the tail to rip apart. It is only designed to withstand feathering at Mach 1.0 and below. Early rumors blamed the engine that was running somewhat rough due to testing a new fuel mixture. If the feathering was unlocked and the engine 'burped' that could have caused the turbulence that deployed the air brake action and tore the ship apart.


Thanks for the explanation.

Hm...... so... *some* pilot error, and maybe bad engineering with the unlock button firing whatever bolts are locking that feather tail in place.

Just one button, switch, or lever, whatever it was.

You'd think something so "do not touch" important would be a big crank you've got to ratchet up, with some tension, to make sure you really are sure.

Important buttons should have a cover over the switch and stick the mission-ending buttons somewhere off from the other buttons. I don't know the details of course, why would the feather tail be unlocked like that.

Image

I heard it speculated there could have been some problem in flight that the pilot thought the feather tail deployed would help with, we don't know, but really that thing is only supposed to be lowered at the lower speed as you say (heck, why wasn't there a computer altimeter master locking it).
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Re: Space Ship Two Crash

Unread postby Tanada » Mon 03 Nov 2014, 08:29:39

In normal flight it is a two step process, first control unlocks the tail feather, second switch uses a motor to deploy the feather 90 degrees.

Accidents happen, as much as people practice and train to avoid them it still happens. Humans are imperfect.
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Re: Space Ship Two Crash

Unread postby Keith_McClary » Mon 03 Nov 2014, 21:00:30

Tanada wrote:In normal flight it is a two step process, first control unlocks the tail feather, second switch uses a motor to deploy the feather 90 degrees.

Accidents happen, as much as people practice and train to avoid them it still happens. Humans are imperfect.
Why do they have human pilots?
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Re: Space Ship Two Crash

Unread postby dissident » Mon 03 Nov 2014, 21:10:00

Keith_McClary wrote:
Tanada wrote:In normal flight it is a two step process, first control unlocks the tail feather, second switch uses a motor to deploy the feather 90 degrees.

Accidents happen, as much as people practice and train to avoid them it still happens. Humans are imperfect.
Why do they have human pilots?


Because passengers feel safer.
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Re: Space Ship Two Crash

Unread postby Sixstrings » Mon 03 Nov 2014, 21:41:14

Maybe I'm wrong about this, but I *thought* I'd read before that actually the passenger VG spaceship wouldn't have pilots at all, just the passengers.

Which would sure be a creepy flight, lost in space with 5 other strangers or whatever and there's no pilot.

I guess -- it takes TIME to perfect all this, look at all the automation on newer boeing planes and airbus. They've dramatically reduced pilot error, you've got the computer audibly warning the pilot about everything, and such good autopilot systems on those. (i.e. "pull up, pull up)

Spaceship One and Two are just new. It's not a government funding this. There's cushion here to allow for failures until it gets perfected, like with a government rocket program. Even gov cancels stuff once things are failing and it's dragging on forever. Government wouldn't have kept funding this thing, they would have given up.

That craft that went down cost half a billion dollars. Maybe because the pilot unlocked the tail fin in error. They apparently don't have automation and warning systems built in, all that takes trial and error and time.

Even with automation.. there's all those lines of code.. one f*ckup by a programmer can mess it all up.

Even with government supporting something like this, maybe you just wind up with a Concorde that is never profitable or practical.

Don't know what the answer is, other than one day we will have suborbital passenger planes, it'll make sense if they can be bigger than the concorde, and it would cut travel time from 8 hours to 45 minutes.
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Re: Space Ship Two Crash

Unread postby Sixstrings » Mon 03 Nov 2014, 21:53:30

Speaking of automation and code..

I was watching a documentary about the New Horizons probe that reaches Pluto next year. So anyway, it has to be all automated because that's so far out.

So what they did was they had a separate computer with all the same code and they just tested that first over and over to be sure there were no bugs.

And then when it did its Jupiter flyby they used that as a dress rehearsal for Pluto.

They said "one line of bad code can ruin it all." So this stuff isn't impossible, you just can't have any mistakes is all. You gotta get it perfect. Whatever can go wrong will go wrong and you've gotta plan for every eventuality in advance, and redundant backup systems. And good design, and plan to prevent pilot error.

And even then, when you've done all you can, like with the space shuttle there is still an accident now and then. The o rings, launching in cold weather. Then those titles finally came off on columbia after getting hit by something -- lose a few heat shield tiles and that's it, the craft burns up.

Whatever can go wrong, will go wrong.

This really makes no sense, that VG craft sounds like a prototype, it shouldn't have been possible to accidentally unlock the feather tail. Anyhow it looks like the program is all over now, that's that.
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Re: Space Ship Two Crash

Unread postby Tanada » Thu 13 Nov 2014, 16:04:53

The National Transportation Safety Board (NTSB) issued an investigative update Wednesday into the crash of SpaceShip Two on Oct. 31, 2014, in Mojave, Calif. Investigators revealed that pilot Peter Siebold of the Virgin Galactic crash was able to survive because he was still strapped in his seat as the plane broke apart in midair but was able to free himself. “According to the pilot, he was unaware that the feather system had been unlocked early by the copilot,” the NTSB said. “He stated that he was extracted from the vehicle as a result of the break-up sequence and unbuckled from his seat at some point before the parachute deployed automatically.”

The spaceship, which is part of a program that will take passengers into space, had just broken the sound barrier and was 10 miles high when it broke up during the Oct. 31 test flight. The incident occurred just after the craft was dropped from the WhiteKnightTwo, the mother ship.

NTSB investigators have focused on video and telemetry showing that co-pilot Mike Alsbury prematurely unlocked the tail feather rotation system as SpaceShipTwo accelerated through Mach 1.

Alsbury died at the scene of the crash. Siebold received minor surgery for a shoulder injury and was recently released from the hospital.

The update did not provide any details on what caused SpaceShipTwo to crash in the Mojave Desert.

The NTSB has completed the on-scene investigation of the crash location in the Mojave Desert of California. The recovered wreckage of SpaceShipTwo is now stored in a secure location, the NTSB said.

A group of NTSB investigators will assemble next week at the board’s recorders laboratory to evaluate the video footage.
http://www.astrowatch.net/2014/11/investigators-reveal-how-pilot-survived.html
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Re: Space Ship Two Crash

Unread postby Subjectivist » Wed 14 Jan 2015, 17:19:37

Virgin Galactic is making rapid progress, more at link at bottom.

Less than 10 weeks after a fatal crash that destroyed a suborbital rocket plane and raised questions about the future Virgin Galactic, the company’s chief executive says engineers are developing a test program for a replacement spaceship expected to fly later this year.

“Our company is turning the corner and looking to the future,” said George Whitesides, Virgin Galactic’s CEO, in a Jan. 9 speech at the American Institute of Aeronautics and Astronautics Science and Technology Forum and Exposition in Orlando, Fla. “Our team and our investors remain committed to the goal of opening space to all.”

Virgin Galactic, part of Richard Branson’s Virgin Group, was aiming to complete qualification of the rocket-powered plane in time to begin space tourist flights to the edge of space this year.

Whitesides said commercial service is now expected to begin in 2016.

Virgin Galactic’s SpaceShipTwo rocket plane is designed to reach the internationally-recognized boundary of space at an altitude of 100 kilometers, or about 62 miles. More than 700 individuals have signed up to pay approximately $250,000 to ride the rocket plane when it is operational.

Whitesides called the Oct. 31 crash of a SpaceShipTwo test vehicle “the toughest thing that our business could undergo.”

The space plane tumbled out of control 13 seconds after dropping from an enormous carrier jet over California’s Mojave Desert. Its hybrid rocket motor, burning a mixture of solid propellant and nitrous oxide, fired at an altitude of about 50,000 feet to begin SpaceShipTwo’s first test flight since January 2014.

Moments later, co-pilot Michael Alsbury unlocked the spacecraft’s aerodynamic braking system earlier than designed, according to National Transportation Safety Board investigators.

The rocket plane almost immediately broke apart once its tail feathering braking fins — already unlocked — extended without receiving a command to do so from the pilots.

The NTSB investigation is not expected to finish until later this year, and officials said they would look at all potential technical, programmatic and cultural causes that led to the accident.

Alsbury was killed in the crash. Peter Siebold was blown free of the wrecked spaceship and parachuted to the ground with minor injuries.

Both pilots were employed by Scaled Composites, SpaceShipTwo’s designer and the manufacturer of the rocket plane’s first copy.

The Spaceship Company, a subsidiary of Virgin Galactic, is taking over construction follow-on SpaceShipTwo vehicles. The next in line is nearing completion in the company’s hangar in Mojave, Calif.
http://spaceflightnow.com/2015/01/14/virgin-galactic-planning-spaceshiptwos-return-to-flight/
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