space shuttle main engine igniter
ed
Or other info concerning spark igniters for rocket engines ?
T...@astro.net
>Does anyone have technical info about space shuttle main engine igniters ?
>Or other info concerning spark igniters for rocket engines ?
The shuttle main engines are not ignited by the Spark devices you see if
that's what your talking about. Those are to burn off any excess gases that
may be built up below the engines just before they are lit.
Tom
Dave M.
ed wrote in message <01bdd99f$83f45fe0$4c82...@edahome.xs4all.nl>...
Bo Viger
> Does anyone have technical info about space shuttle main engine
> igniters ?
> Or other info concerning spark igniters for rocket engines ?
I just started lurking in this group, so forgive me if this is another
one of those
commonly asked questions, but since I fly high-powered rockets using
ammonium perchlorate (AP) as fuel, I'd be much more interested in how
NASA
engineers manage to light BOTH SRB's at "exactly" the same time,
"exactly"
when the shuttle swings back to "top dead center" following main engine
ignition..
Lighting AP in my hobby, especially in my multi-staged or clustered
motor flights,
is still as much an art as it is a science.
Bo Viger
Tripoli Rocketry Association #1864/Level 2
Tomcat
Bo Viger wrote:
> ed wrote:
>
> > Does anyone have technical info about space shuttle main engine
> > igniters ?
> > Or other info concerning spark igniters for rocket engines ?
>
> I just started lurking in this group, so forgive me if this is another
> one of those
> commonly asked questions, but since I fly high-powered rockets using
> ammonium perchlorate (AP) as fuel, I'd be much more interested in how
> NASA
> engineers manage to light BOTH SRB's at "exactly" the same time,
> "exactly"
> when the shuttle swings back to "top dead center" following main engine
> ignition..
>
It has to do with the the ratio of the stack weight to the engine thrust.
I'm not sure, but I imagine that the SSME's will light at different times
(milliseconds) depending on the load of the vehicle. Or it could be always
at the same time, I dunno, but that seems to be the most logical
suggestion.
Damon Hill
>commonly asked questions, but since I fly high-powered rockets using
>ammonium perchlorate (AP) as fuel, I'd be much more interested in how
>NASA
>engineers manage to light BOTH SRB's at "exactly" the same time,
>"exactly"
>when the shuttle swings back to "top dead center" following main engine
>ignition..
That's nothing. Delta lights six solids simultaneously on the ground, and
three in flight; Titan III and IV do the same thing as Shuttle, and as do
various models of Ariane, the H-2 and other rockets. All quite reliably
and timely, too.
--Damon
Henry Spencer
> ammonium perchlorate (AP) as fuel, I'd be much more interested in how
Well, it helps to have igniters the size of a garbage can, weighing 300kg
each. :-) The SRB igniter is a specialized solid rocket itself, firing
down the bore of the SRB from the top. When you apply lots of flame to
the fuel, it ignites pretty predictably.
(The igniter itself is lit by *another* specialized solid rocket, the
initiator, this one about the size of your head. It's lit by a charge of
pyro compound about the size of a modest HPR motor. Which is lit by a
pair of electrically-activated pyro devices, NASA Standard Initiators.)
An ignition failure, or a significantly asymmetric ignition, is a Real
Bad Day For NASA. At the very least, it will total the orbiter (and
crew) and probably badly damage the pad.
--
Being the last man on the Moon is a | Henry Spencer he...@spsystems.net
very dubious honor. -- Gene Cernan | (aka he...@zoo.toronto.edu)
Tomcat
Henry Spencer wrote:
> An ignition failure, or a significantly asymmetric ignition, is a Real
> Bad Day For NASA. At the very least, it will total the orbiter (and
> crew) and probably badly damage the pad.
At the very least? Losing the orbiter and crew? If that's at the very least,
then what's worst case scenario?
Henry Spencer
I should probably have reconsidered that wording...
However, let's see. Worst case (in addition to the above) would be if
Range Safety hesitates for a few seconds, or some of the destruct systems
are damaged in the breakup, and one of the SRBs runs wild, smashes into
the VAB, and explodes. Assuming that debris from the destruction of the
VAB will pretty much demolish the lower buildings at its base -- that is,
KSC launch control and the orbiter processing facilities -- that could
take out the entire orbiter fleet and most of its major support facilities
at one blow.
I guess *absolute* worst case is if (a) the President is in launch control
to see the launch, and (b) the other SRB gets away and hits the Spouses'
Event at a convention of liability lawyers in Orlando.
Graham Nelson
> Henry Spencer wrote:
> > An ignition failure, or a significantly asymmetric ignition, is a Real
> > Bad Day For NASA. At the very least, it will total the orbiter (and
> > crew) and probably badly damage the pad.
>
> At the very least? Losing the orbiter and crew? If that's at the very least,
> then what's worst case scenario?
Doing so when Senator Glenn is on board, perhaps. Or entirely
destroying Pad 39B and its approach track, plus a large U.S.
component of the International Space Station.
Or the Shuttle could take off, skew right over, wreck the Pad
in the process and careen wildly into the VAB and the Orbiter
Processing Facility, destroying all the other Shuttles too and
most of the infrastructure and everybody who works there.
It's very unlikely and a group of fine engineers labour tirelessly
to prevent it, of course. I once read a marvellous book about
safety engineering, which began with the claim that a good
engineer is one who makes himself a new table knife and then stops
to work out the chances of it snapping off in use, thus firing
off a fragment of blade out of the window that happens to be open
and right into somebody passing by. A really terrible if horribly
unlikely worst case scenario can be a sign of good engineering,
because it shows that the proper degree of careful thought has
been invested.
--
Graham Nelson | gra...@gnelson.demon.co.uk | Oxford, United Kingdom
Brian S. Thorn
>
>
>Henry Spencer wrote:
>
>> An ignition failure, or a significantly asymmetric ignition, is a Real
>> Bad Day For NASA. At the very least, it will total the orbiter (and
>> crew) and probably badly damage the pad.
>
>At the very least? Losing the orbiter and crew? If that's at the very least,
>then what's worst case scenario?
Flaming debris landing on and around the VIP and Press Sites, killing
or wounding scores of bystanders. Ick.
Brian
Paul Dietz
The SRB range safety receivers are at the front
the the SRBs, right? How about an accident
in which one of the SRBs careens into the ground/
ocean/pad structure and breaks the safety equipment
before the range safety officer can push the button.
The shuttle (unlike unmanned launchers) doesn't
have an automatic system that explodes the range
safety charges if the stack falls apart.
Paul
Greg Moore (Strider)
>
> Henry Spencer wrote:
>
> > An ignition failure, or a significantly asymmetric ignition, is a Real
> > Bad Day For NASA. At the very least, it will total the orbiter (and
> > crew) and probably badly damage the pad.
>
> At the very least? Losing the orbiter and crew? If that's at the very least,
> then what's worst case scenario?
Loosing specators at the 3 mile mark. Depending on how quickly the
Range Safety Officer reacts, the shuttle stack could get close enough to
kill spectators or bystanders.
--
Greg D. Moore President moo...@greenms.com
Green Mountain Software http://www.greenms.com/
518-283-4083 MCSE
Roger Mitchell
>
> An ignition failure, or a significantly asymmetric ignition, is a Real
> Bad Day For NASA. At the very least, it will total the orbiter (and
> crew) and probably badly damage the pad.
This is a BIG understatement. Loss at ignition of either of the SRBs is
going to be one really, really bad day. One scenerio (right SRB failure
at ignition) has the whole stack going into the VAB complex off of Pad
A.
Luckily, the whole system (like those on the Delta and Titan, and
probably
the Arianne and others) is WAY redundant so that won't happen.
> --
> Being the last man on the Moon is a | Henry Spencer he...@spsystems.net
> very dubious honor. -- Gene Cernan | (aka he...@zoo.toronto.edu)
Roger
Jeramie Hicks
wrote:
>This is a BIG understatement. Loss at ignition of either of the SRBs is
>going to be one really, really bad day. One scenerio (right SRB failure
>at ignition) has the whole stack going into the VAB complex off of Pad
>A.
That's why they use those sparklers underneath the engines to light
them every time. :-)
- Hicks
Damon Hill
Not.
--Damon
Lynn Killingbeck
>
> On Sun, 13 Sep 1998 23:48:47 -0500, Roger Mitchell <rmit...@ghg.net>
> wrote:
>
> >This is a BIG understatement. Loss at ignition of either of the SRBs is
> >going to be one really, really bad day. One scenerio (right SRB failure
> >at ignition) has the whole stack going into the VAB complex off of Pad
> >A.
>
> That's why they use those sparklers underneath the engines to light
> them every time. :-)
>
I wonder how many will take your silly statement seriously!?!? <g>
Lynn Killingbeck
Paul Dietz
> > them every time. :-)
> I wonder how many will take your silly statement seriously!?!? <g>
"<g>", ":-)", indeed!
Paul
Roger Mitchell
>
> In article <35fd599d...@newshost.cc.utexas.edu>, Jerami...@mail.utexas.edu (Jeramie Hicks) wrote:
> >On Sun, 13 Sep 1998 23:48:47 -0500, Roger Mitchell <rmit...@ghg.net>
> >wrote:
> >
> >>This is a BIG understatement. Loss at ignition of either of the SRBs is
> >>going to be one really, really bad day. One scenerio (right SRB failure
> >>at ignition) has the whole stack going into the VAB complex off of Pad
> >>A.
> >
> >them every time. :-)
>
>
> --Damon
C'mon Damon, read all the way >through< the little emoticon. Humor is
still
fun to have, isn't it?
Roger