Author Topic: Basic Rocket Science Q & A  (Read 281093 times)

Offline Antares

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Re: Basic Rocket Science Q & A
« Reply #360 on: 11/08/2009 03:20 PM »
Sit in your car.  If it's modern, there's a fairly good chance your surrounded by ordnance devices that drive the airbags.  It's been a major growth segment for suppliers who previously had only government business.
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Offline Art LeBrun

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Re: Basic Rocket Science Q & A
« Reply #361 on: 11/08/2009 04:01 PM »
Shown is the integration of a Delta first stage and the second stage/shroud structure. Note the "many registration pins" ready to be inserted in the matching holes in the first stage. Is this a common matching procedure? Why are so many pins required? And how can I improve my vernacular on these questions?
« Last Edit: 11/08/2009 04:07 PM by Art LeBrun »
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Offline Art LeBrun

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Re: Basic Rocket Science Q & A
« Reply #362 on: 11/08/2009 06:34 PM »
Experts on this forum have said Titan IIs used for launching early space missions did not need an escape tower because the propellants are hypergolic and will deflagrate instead of detonating. Further googling reveals that this 'barely' enabled the use of ejection seats.


So, would you need an escape tower for a kerosene/peroxide launcher or would ejection seats be enough?

Isn't there an altitude restriction for ejection seats? How often has lox/kerosene "detonated"?
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Offline Antares

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Re: Basic Rocket Science Q & A
« Reply #363 on: 11/08/2009 09:55 PM »
On first order, I don't find detonation credible as the root cause of an LOC event.  There would have to be fuel/LOX or fuel/air mixing BEFORE the application of an ignition source.  More likely, the propellants would deflagrate with the existing ignition sources (exhaust or firing ordnance).  The crew compartment would be able to get away from the cloud before mixing and ignition could occur.
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Offline mmeijeri

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Re: Basic Rocket Science Q & A
« Reply #364 on: 11/08/2009 10:44 PM »
So are you saying detonation is unlikely to begin with, regardless of whether the propellants are hypergolic? What about Challenger?
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Offline Art LeBrun

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Re: Basic Rocket Science Q & A
« Reply #365 on: 11/09/2009 12:53 AM »
So are you saying detonation is unlikely to begin with, regardless of whether the propellants are hypergolic? What about Challenger?

Challenger broke up with the propellants spilling and igniting in the air. Not much of a detonation...............
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Offline mmeijeri

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Re: Basic Rocket Science Q & A
« Reply #366 on: 11/09/2009 01:01 AM »
We're getting close to a very sensitive subject here, so I'll try to be careful. Suppose the ejection seats for the pilot and commander had not been disabled, would they have been able to survive the disaster? I realise it is unacceptable to give some crew members an escape option others do not have, but I'm wondering how this relates to potential survivability in a future spaceplane.
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Offline mmeijeri

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Re: Basic Rocket Science Q & A
« Reply #367 on: 11/09/2009 01:14 AM »
To the best of my knowledge in all those years there has never been an accidental ignition of one.

Here's such a story, but it was a passenger who accidentally triggered an eject, not a pilot or a malfunction:

Plane passenger accidentally activates ejector seat - and survives

Quote
Ejection seats would likely have saved most of Challenger's crew as it has been reliably reported that they were alive, and probably conscious, inside the descending crew cabin which had survived the explosion intact, all the way down to ocean impact.

I suppose that answers my previous question.
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Offline kch

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Re: Basic Rocket Science Q & A
« Reply #368 on: 11/09/2009 01:47 AM »
We're getting close to a very sensitive subject here, so I'll try to be careful. Suppose the ejection seats for the pilot and commander had not been disabled, would they have been able to survive the disaster? I realise it is unacceptable to give some crew members an escape option others do not have, but I'm wondering how this relates to potential survivability in a future spaceplane.

To the best of my knowledge, the only flight with disabled ejection seats was STS-5 (first non-Orbital-Flight-Test flight, crew of 4) in Columbia.  After that flight, the ejection seats were removed to save weight and make room for 4 crew on the flight deck.  IIRC, none of the other orbiters (with the possible exception of Enterprise) had ejection seats.

Offline Jorge

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Re: Basic Rocket Science Q & A
« Reply #369 on: 11/09/2009 05:04 AM »

Ejection seats would likely have saved most of Challenger's crew as it has been reliably reported that they were alive, and probably conscious, inside the descending crew cabin which had survived the explosion intact, all the way down to ocean impact.

It's been reliably reported that they were alive but probably *unconscious*.
JRF

Offline MKremer

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Re: Basic Rocket Science Q & A
« Reply #370 on: 11/09/2009 05:21 PM »
Shown is the integration of a Delta first stage and the second stage/shroud structure. Note the "many registration pins" ready to be inserted in the matching holes in the first stage. Is this a common matching procedure? Why are so many pins required? And how can I improve my vernacular on these questions?

Those are the bolts that attach the interstage adapter to the first stage. If you look closely, there are threads at the end of each one.

A few more views, showing the bolt holes from inside and adapters being mated both with and without the bolts in place:

http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=24565
http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=24594
http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=43889


« Last Edit: 11/09/2009 05:22 PM by MKremer »

Offline Art LeBrun

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Re: Basic Rocket Science Q & A
« Reply #371 on: 11/10/2009 03:41 AM »
Shown is the integration of a Delta first stage and the second stage/shroud structure. Note the "many registration pins" ready to be inserted in the matching holes in the first stage. Is this a common matching procedure? Why are so many pins required? And how can I improve my vernacular on these questions?

Those are the bolts that attach the interstage adapter to the first stage. If you look closely, there are threads at the end of each one.

A few more views, showing the bolt holes from inside and adapters being mated both with and without the bolts in place:

http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=24565
http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=24594
http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=43889




Thank you for the images and explanation. Now for additional questions.

1) why some with and some without bolts?
2) how are bolts secured? threaded insert on first stage or nuts attached later? access panel obviously available........I seem to see counterbores for bolts on interstage.
1958 launch vehicle highlights: Vanguard TV-4 and Atlas 12B

Offline sbt

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Re: Basic Rocket Science Q & A
« Reply #372 on: 11/10/2009 11:50 PM »
To the best of my knowledge in all those years there has never been an accidental ignition of one.

Here's such a story, but it was a passenger who accidentally triggered an eject, not a pilot or a malfunction:

We also suffered one during the introduction of the Harrier GR5. A Wander Lamp fell to the floor. The pilot motored the seat down to adjust his eyeline to avoid sun in his eyes. The lamp was under the linkage to part the parachute system. The slug used to drag the cute out of its container was fired, simultaneously triggering the seat straps to release, broke the canopy and pulled the cute into the airstream. The pilot did not survive the decent on a shredded parachute. The lamp was eliminated and a FOD shield added to the bottom of the seat.

Most Ejector Seat accidents, however, are during ground handeling. Personnel MUST check that the pins are in before working in the cockpit area.

Rick
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Offline tva

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Re: Basic Rocket Science Q & A
« Reply #373 on: 11/26/2009 08:55 AM »
Chris has just reported that Atlantis has raised her orbit with a burn wich was radial down (nose to the Earth).

I tought that a nose-down burn would rather alter apogee/perigee then raise orbit.

Could someone cast some light on this  ??? ?
« Last Edit: 11/26/2009 08:56 AM by tva »
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Offline Jorge

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Re: Basic Rocket Science Q & A
« Reply #374 on: 12/12/2009 08:57 PM »
Chris has just reported that Atlantis has raised her orbit with a burn wich was radial down (nose to the Earth).

I tought that a nose-down burn would rather alter apogee/perigee then raise orbit.

Could someone cast some light on this  ??? ?

That was a live mission thread, most likely Chris was quoting NASA PAO from NASA TV and something got garbled in the chain.
JRF

Offline Antares

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Re: Basic Rocket Science Q & A
« Reply #375 on: 12/28/2009 02:29 AM »
Moved from SpaceX thread:
IIRC, if LOX soaks into a fuel like boot polish or coal or asphalt, it can form a shock sensitive explosive. So the boot wouldn't explode immediately, it would probably wait until you stamped to attention.

Coal & LOX used to a common mining explosive, but there were too many unexpected detonations.

Google Atlas 71F and oxyliquit.
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Online HMXHMX

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Re: Basic Rocket Science Q & A
« Reply #376 on: 12/28/2009 04:33 AM »
Moved from SpaceX thread:
IIRC, if LOX soaks into a fuel like boot polish or coal or asphalt, it can form a shock sensitive explosive. So the boot wouldn't explode immediately, it would probably wait until you stamped to attention.

Coal & LOX used to a common mining explosive, but there were too many unexpected detonations.

Google Atlas 71F and oxyliquit.

And you get:  "Access to this server is forbidden from your client"

Offline Art LeBrun

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Re: Basic Rocket Science Q & A
« Reply #377 on: 12/28/2009 04:41 AM »
Moved from SpaceX thread:
IIRC, if LOX soaks into a fuel like boot polish or coal or asphalt, it can form a shock sensitive explosive. So the boot wouldn't explode immediately, it would probably wait until you stamped to attention.

Coal & LOX used to a common mining explosive, but there were too many unexpected detonations.

Google Atlas 71F and oxyliquit.

And you get:  "Access to this server is forbidden from your client"

click on "view as html" on second line. I wonder what the recent SLC-2W event was?
« Last Edit: 12/28/2009 04:45 AM by Art LeBrun »
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Offline yinzer

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Re: Basic Rocket Science Q & A
« Reply #378 on: 12/28/2009 08:26 PM »
Summary: LOX and RP-1 coming out an overflow line pooled in the flame deflector and exploded prior to launch.  Damage to the vehicle caused premature engine shut down followed by range safety pushing the button at T+303.

Given that the vehicle was able to take off and fly more or less normally for five seconds after a substantial leak of fuel and oxidizer on the launch pad, I'm not convinced that this shows LOX/RP-1 to be any more dangerous than your typical hypergolics.
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Offline Art LeBrun

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Re: Basic Rocket Science Q & A
« Reply #379 on: 12/28/2009 09:01 PM »
I would like to know the actual effect on Atlas 71F from the explosion at ignition. It appears to have functioned through staging so we had about 130 seconds of flight at least and what caused the sustainer cutoff at what time?

Reminds me of two Atlas E at the Cape when the hydraulics rise off valve failed to close allowing fluid to drain and after staging the sustainer engine had no flight control.
1958 launch vehicle highlights: Vanguard TV-4 and Atlas 12B