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Author
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Topic: Soviet Vostok spacecraft ejection system
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Tonyq
Member Posts: 199
From: UK
Registered: Jul 2004
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posted 03-06-2005 01:31 PM
   
It's always been recorded that the Vostok ejection system was designed for both cosmonaut recovery, at the conclusion of a flight, and as an escape mechanism in the event of a launch abort.However, I'd be interested to hear from anyone who has the technical know-how to confirm that it was definitely viable in the latter role. I ask because it seems unlikely that such a system could actually propel a cosmonaut sitting on the pad, in a 45 degree position to an altitude of say, 500ft, which would be the minimum required to make such an ejection survivable. Bearing in mind that the Soviets later launched two manned Voskhods without any launch escape system, is it possible that in practical terms, Vostok also lacked this safety facility. |
FFrench
Member Posts: 3161
From: San Diego
Registered: Feb 2002
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posted 03-06-2005 03:10 PM
If anything had gone wrong on the launch pad, the ejector seat would have fired the cosmonaut out, but there was not enough time or altitude for a parachute to open. Instead, they would have fallen into a large net that was provided. |
Tonyq
Member Posts: 199
From: UK
Registered: Jul 2004
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posted 03-08-2005 06:30 PM
Do you have any pictures or sources for this 'net' reference.My thoughts are, that his would be very difficult to make work, as in the event of a pad evacuation, there would be so many variables that you would need a net which covered a significant area! Also, is a landing in an ejection seat considered a survivable incident in the aviation world generally? |
FFrench
Member Posts: 3161
From: San Diego
Registered: Feb 2002
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posted 03-09-2005 11:03 PM
It took me a while to remember my source for that - it is "Starman" (the Gagarin biography), Pages 81-2. They describe "a huge array of netting on the ground 1,500 meters away from the pad. The cosmonaut would fall into this, just so long as all the calculations were right." This was apparently only for before the rocket had lifted off. "Starman" does have errors in it, and so if someone out there knows that this is not accurate, please let me know, I'd be most interested.Very reliable information can be found in Rex Hall and David Shayler's marvelous book "The Rocket Men." P.91 discusses the angle of ejection from the rocket. The ejection seat was propelled out and slightly upwards by solid rockets, and the parachute was specially modified for low opening, both of while would increase the success of a low-altitude ejection. Rex is a regular poster to this site, so may be able to add more. I'd recommend "The Rocket Men," by the way, to anyone interested at all in the first Soviet manned spaceflights - it is a wonderful read! |
Tonyq
Member Posts: 199
From: UK
Registered: Jul 2004
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posted 03-10-2005 04:46 PM
Thanks for taking the trouble to look up that reference source. I don't have 'Starman', which may explain why I've never read this before.It does seem an extraordinary concept that they would fire the cosmonaut a mile into such a net, rather like the circus 'human cannonball'. Presumably, they would also land still in the ejection seat, which must have presented it's own risks. I had studied the reference in 'The Rocket Men' before I posted my initial note, and agree that Rex and Dave have covered the specification of the ejector seat very well, but I'm still not sure that it would take the cosmonaut to sufficient altitude, from the pad, to make a parachute descent. I haven't addressed this question directly to Rex, but I'm sure he'll spot this thread and add a comment in due course.
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spaceuk
Member Posts: 2113
From: Staffs, UK
Registered: Aug 2002
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posted 03-18-2005 05:27 AM
Most seat ejection systems in fighter aircraft will launch the unfortunate occupant to sufficient height to be able to do an emergency parachute landing. There have been several examples of near ground zero ejections where crew has survived in recent years from jet aircraft at public airshows . I would have thought Gagarin would have survived had he needed to eject with a parachute and without a net. |
spaceuk
Member Posts: 2113
From: Staffs, UK
Registered: Aug 2002
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posted 03-18-2005 05:47 AM
I thought I had read - somewhere awhile ago - that netting was an effort to stop wild life from roaming to close the pads ?
I'll see if I can remember where I read that. There is substantial fencing around the area as well to stop wild animals from straying onto the launch pads. |
spaceuk
Member Posts: 2113
From: Staffs, UK
Registered: Aug 2002
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posted 03-21-2005 07:05 AM
Here is an image of the several fences surrounding the Soyuz pad at Baikonur. |
spaceuk
Member Posts: 2113
From: Staffs, UK
Registered: Aug 2002
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posted 04-03-2005 02:34 PM
Almost contemporary with the Vostok spacecraft was the American two-man Gemini vehicleLooking at some technical papers they gave values for the Gemini ejection seat for off-the-pad escape mode. They noted that the rocket impulse of these seats was 2650 lbs.sec Once clear of the rocket, the astronaut was ejected from the seat using a gas cartridge operated actuator. It was estimated that if the Titan rocket was to explode then the fireball that would form would take 2.94 seconds to reach 90 foot radius and 6.94 seconds to reach a 230 feet radius. An ejected astronaut would reach between 205 feet and 466 feet altitude by the time the fireball got to the 90 foot radius from launch pad. On the 466 feet height the astronaut would float down on his parachute to about 550 feet from launch pad some 23 seconds after ejecting. If the astronaut got to 205 feet he would float down to 720 feet radius from rocket at about 8 seconds after ejecting. You would expect somewhat similar data for a Vosotok seat. |
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