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  #11  
Old April 8th 13, 09:35 AM posted to sci.space.station
Brian Gaff
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Posts: 2,312
Default Antares

Maybe like me you were expecting it to all go wrong then. do people bet on
launch vehicles crashing I wonder. That ESA/Russian one back some years
where all the first stage engines stopped at about 2000 feet has to be one
of the classics in badly designed control software!

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Jeff Findley" wrote in message
...
In article ,
says...

The rather spectacular looking Antares launch failure seems to have been
a systems integration problem, not a problem with the individual stages.
Some unidentified vibration caused the control system to compensate for
an error that wasn't there. This caused the fluid (used for gimbal
control) to be exhausted too early, causing the stack to lose control.

Yet another downside for solids. They need a system for gimbaling
independent of the solid propellant/thrust chamber.

A LOX/kerosene engine, on the other hand, can use kerosene bled from the
high pressure turbo-pump exit for hydraulic control, so there is no
chance of "running out" of fluid for gimbal control as long as the
engine keeps running.


I typed "Antares launch failure" when I should have typed "Conestoga
1620 launch failure".

http://www.astronautix.com/lvs/cona1620.htm

From above:

FAILU Noise in guidance system led to excessive steering of
one of the booster motors and finally depletion of the motor's
hydraulic fluid. The vehicle went out of control at T+46
seconds.. Failed Stage: G.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer



  #12  
Old April 8th 13, 10:41 AM posted to sci.space.station
Mika Takala[_8_]
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Posts: 4
Default Antares

On 8.4.2013 11:35, Brian Gaff wrote:
Maybe like me you were expecting it to all go wrong then. do people bet on
launch vehicles crashing I wonder. That ESA/Russian one back some years
where all the first stage engines stopped at about 2000 feet has to be one
of the classics in badly designed control software!

Brian


You must be thinking of Foton-1 which was a failure of Soyuz rocket.

It is standard Russian operating procedure to just shut down all engines
in case of a failure. No self destruct system. That also applies to the
ones launched from Kourou, according to some sources.

The posivitive is that the impact point will always be known and it will
be well contained.

--
Mika Takala

  #13  
Old April 8th 13, 11:16 AM posted to sci.space.station
Brian Gaff
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Posts: 2,312
Default Antares

Oh so they managed to kill a soldier and injure many with flying debris
then, seems a bit risky when you are launching from a land based site with
no ociean to let the debris fall into.

If I recall some foreign objuct got int a fuel line to one engine. I'd have
thought that if the other engines had been kept going the damage on the
ground would not have occured as it would be further away with less fuel
left.

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Mika Takala" wrote in message
...
On 8.4.2013 11:35, Brian Gaff wrote:
Maybe like me you were expecting it to all go wrong then. do people bet
on
launch vehicles crashing I wonder. That ESA/Russian one back some years
where all the first stage engines stopped at about 2000 feet has to be
one
of the classics in badly designed control software!

Brian


You must be thinking of Foton-1 which was a failure of Soyuz rocket.

It is standard Russian operating procedure to just shut down all engines
in case of a failure. No self destruct system. That also applies to the
ones launched from Kourou, according to some sources.

The posivitive is that the impact point will always be known and it will
be well contained.

--
Mika Takala



  #14  
Old April 8th 13, 02:18 PM posted to sci.space.station
Jeff Findley[_2_]
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Posts: 1,388
Default Antares

In article , bthorn64
@suddenlink.net says...

On Fri, 5 Apr 2013 09:57:02 -0400, Jeff Findley
wrote:


FAILU Noise in guidance system led to excessive steering of
one of the booster motors and finally depletion of the motor's
hydraulic fluid. The vehicle went out of control at T+46
seconds.. Failed Stage: G.


Isn't that the one where the range safety destruct command didn't work
either? They were just lucky it didn't veer back toward Wallops.


Yes, the thrust termination systems didn't work on all the boosters, so
they literally flew out of control after the stack tore itself apart.

Anyway, I think Henry Spencer wrote that SRB-X was the worst launch
vehicle design ever. But for my money, I would pick Conestoga.


Anything with large solids is right up there, IMHO.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer
  #15  
Old April 8th 13, 06:36 PM posted to sci.space.station
Mika Takala[_8_]
external usenet poster
 
Posts: 4
Default Antares

On 8.4.2013 13:16, Brian Gaff wrote:
Oh so they managed to kill a soldier and injure many with flying debris
then, seems a bit risky when you are launching from a land based site with
no ociean to let the debris fall into.


Thats only to do with too relaxed ground safety perimeters.


If I recall some foreign objuct got int a fuel line to one engine. I'd have
thought that if the other engines had been kept going the damage on the
ground would not have occured as it would be further away with less fuel
left.


... but it would have flown perhaps uncontrolled and the impact location
would have been different.

There is a complete difference in design philosophy. The Russians really
try to contain the damage instead of spreading debris into huge area
(rocket blown into pieces) or unexpected places (by continuing flight in
uncontrolled way).

--
Mika Takala

  #16  
Old April 8th 13, 06:52 PM posted to sci.space.station
Greg \(Strider\) Moore
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Posts: 790
Default Antares

"Mika Takala" wrote in message ...

On 8.4.2013 13:16, Brian Gaff wrote:
Oh so they managed to kill a soldier and injure many with flying debris
then, seems a bit risky when you are launching from a land based site
with
no ociean to let the debris fall into.


Thats only to do with too relaxed ground safety perimeters.


If I recall some foreign objuct got int a fuel line to one engine. I'd
have
thought that if the other engines had been kept going the damage on the
ground would not have occured as it would be further away with less fuel
left.


.. but it would have flown perhaps uncontrolled and the impact location
would have been different.

There is a complete difference in design philosophy. The Russians really
try to contain the damage instead of spreading debris into huge area
(rocket blown into pieces) or unexpected places (by continuing flight in
uncontrolled way).


Except the rocket isn't "blown to pieces". Generally the fuel tank is
opened up (which may result in an explosion) but the net result is similar.
Assured termination of thrust so that crash point can be somewhat
controlled.

Note, that the range safety is independent of the thrust. i.e. if something
fails in the engine controller (which might prevent a shutdown) the range
safety should still work.

The other benefit of doing this at altitude is that hopefully you're not
landing 1000s of lbs of propellant in one spot.

Gut level I'd rather go with range safety rather than simple thrust
termination.



--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

  #17  
Old April 11th 13, 03:37 PM posted to sci.space.station
Me
external usenet poster
 
Posts: 489
Default Antares

On Apr 4, 3:39*pm, Jeff Findley wrote:
In article ,
says...



"Brian Gaff" *wrote in ...


So though I wish Orbital well, their track record for trouble free first
launches is not great. Lets hope this one is an exception!


Incidentally what was that *launch vehicle called in the 90s that launched
from the same site but *blew up leaving a couple of *out of control solids
racing upward? I believe it was cancelled shortly after that failure.


http://en.wikipedia.org/wiki/Conestoga_(rocket)


Is this the one you're thinking of?


Clusters of solids with low payload to orbit. *Not my idea of low cost,
especially once the "surplus" Minuteman stages are all gone.



It used new GEM motors and had nothing to do with Minuteman

  #18  
Old April 15th 13, 01:14 PM posted to sci.space.station
Brian Gaff
external usenet poster
 
Posts: 2,312
Default Antares

Two days to go then...
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Me" wrote in message
...
On Apr 4, 3:39 pm, Jeff Findley wrote:
In article ,
says...



"Brian Gaff" wrote in ...


So though I wish Orbital well, their track record for trouble free
first
launches is not great. Lets hope this one is an exception!


Incidentally what was that launch vehicle called in the 90s that
launched
from the same site but blew up leaving a couple of out of control
solids
racing upward? I believe it was cancelled shortly after that failure.


http://en.wikipedia.org/wiki/Conestoga_(rocket)


Is this the one you're thinking of?


Clusters of solids with low payload to orbit. Not my idea of low cost,
especially once the "surplus" Minuteman stages are all gone.



It used new GEM motors and had nothing to do with Minuteman


  #19  
Old April 18th 13, 07:46 AM posted to sci.space.station
Brian Gaff
external usenet poster
 
Posts: 2,312
Default Antares

Did it go, not heard anything here.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Brian Gaff" wrote in message
...
Two days to go then...
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Me" wrote in message
...
On Apr 4, 3:39 pm, Jeff Findley wrote:
In article ,
says...



"Brian Gaff" wrote in ...


So though I wish Orbital well, their track record for trouble free
first
launches is not great. Lets hope this one is an exception!


Incidentally what was that launch vehicle called in the 90s that
launched
from the same site but blew up leaving a couple of out of control
solids
racing upward? I believe it was cancelled shortly after that failure.


http://en.wikipedia.org/wiki/Conestoga_(rocket)


Is this the one you're thinking of?


Clusters of solids with low payload to orbit. Not my idea of low cost,
especially once the "surplus" Minuteman stages are all gone.



It used new GEM motors and had nothing to do with Minuteman




  #20  
Old April 19th 13, 10:48 AM posted to sci.space.station
Brian Gaff
external usenet poster
 
Posts: 2,312
Default Antares

I see, so a connector was the issue then. Kind of makes you wonder what cna
go wrong thith such a device, consiering the number of launches there have
been one would have thought a foolproof design might have been available off
the shelf.

Brian

--
From the Sofa of Brian Gaff Reply address is active
"JF Mezei" wrote in message
eb.com...
An update:

Orbital has confirmed the next opportunity to test launch its Antares
rocket from NASA's Wallops Flight Facility in Virginia will be no earlier
than 5 p.m. EDT on Saturday, April 20.

NASA TV coverage of the launch will begin at 4:30 p.m. By the time
coverage starts, the launch window will likely have been reduced to 10-15
minutes.


An attempt Friday was called off after review of the weather forecast.
Saturday?s forecast indicates an 85 percent chance of favorable
conditions. If needed, a back-up launch opportunity is available on
Sunday.




 




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