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Unplanned engine-out resiliance test for CRS-1 Falcon 9?



 
 
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  #1  
Old October 8th 12, 11:11 PM posted to sci.space.history
Rick Jones
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Posts: 685
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

It would seem that the most recent Falcon 9 launch included an
unplanned test of its engine-out capability:

http://www.theregister.co.uk/2012/10...alco_flameout/

rick jones
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  #2  
Old October 9th 12, 01:43 AM posted to sci.space.history
Rick Jones
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Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

Rick Jones wrote:
It would seem that the most recent Falcon 9 launch included an
unplanned test of its engine-out capability:


http://www.theregister.co.uk/2012/10...alco_flameout/


And it would seem that a secondary payload isn't quite where it was
meant to be:

http://cosmiclog.nbcnews.com/_news/2...goes-awry?lite

rick jones
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  #3  
Old October 9th 12, 02:37 PM posted to sci.space.history
Jeff Findley[_2_]
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Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

In article ,
says...

Rick Jones wrote:
It would seem that the most recent Falcon 9 launch included an
unplanned test of its engine-out capability:


http://www.theregister.co.uk/2012/10...alco_flameout/

And it would seem that a secondary payload isn't quite where it was
meant to be:

http://cosmiclog.nbcnews.com/_news/2...goes-awry?lite


From what I read today, this is looking more and more like a complete
failure for the secondary payload.

http://www.nasaspaceflight.com/2012/...review-falcon-
9-ascent-issues/

From above, it looks like the plan was to have the second stage do a
burn after Dragon separation. However, the second stage didn't pass a
propellant mass check required by NASA to insure that the satellite
would be inserted into an orbit that would guarantee no risk of
collision with ISS. The backup plan to release the satellite in the
second stage's parking orbit was executed. Because of this, none of the
remaining second stage propellant could be used to help move the
satellite into a more favorable orbit.

I wonder what the final orbit for the secondary payload would have been
if Falcon 9's second stage would have been allowed to perform a final
burn to fuel/oxidizer depletion.

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
  #4  
Old October 9th 12, 06:01 PM posted to sci.space.history
Rick Jones
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Posts: 685
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

Jeff Findley wrote:


From what I read today, this is looking more and more like a
complete failure for the secondary payload.


http://www.nasaspaceflight.com/2012/...review-falcon-
9-ascent-issues/


From above, it looks like the plan was to have the second stage do a
burn after Dragon separation. However, the second stage didn't pass
a propellant mass check required by NASA to insure that the
satellite would be inserted into an orbit that would guarantee no
risk of collision with ISS. The backup plan to release the
satellite in the second stage's parking orbit was executed. Because
of this, none of the remaining second stage propellant could be used
to help move the satellite into a more favorable orbit.


I wonder what the final orbit for the secondary payload would have
been if Falcon 9's second stage would have been allowed to perform a
final burn to fuel/oxidizer depletion.


How long can the second stage "wait" before performing a second (and I
presume final?) burn?

Also, I'm still trying to come to grips with what apart from an
"according to common usage among the peanut gallery" "explosion" would
have caused those pressure relieving panels to blow. "Engine pressure
release" sounds a bit like describing a fire as an "exothermal event
with external charring." I think it was a great demonstration of the
Falcon9's resiliance but euphamisms (assuming they are indeed getting
used here) don't speak well towards organizational resiliance. Or
perhaps it is just my peanut-gallery understanding of terminology.

rick jones
--
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these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
  #5  
Old October 9th 12, 10:05 PM posted to sci.space.history
Jeff Findley[_2_]
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Posts: 1,388
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

In article ,
says...

Jeff Findley wrote:


From what I read today, this is looking more and more like a
complete failure for the secondary payload.


http://www.nasaspaceflight.com/2012/...review-falcon-
9-ascent-issues/


From above, it looks like the plan was to have the second stage do a
burn after Dragon separation. However, the second stage didn't pass
a propellant mass check required by NASA to insure that the
satellite would be inserted into an orbit that would guarantee no
risk of collision with ISS. The backup plan to release the
satellite in the second stage's parking orbit was executed. Because
of this, none of the remaining second stage propellant could be used
to help move the satellite into a more favorable orbit.


I wonder what the final orbit for the secondary payload would have
been if Falcon 9's second stage would have been allowed to perform a
final burn to fuel/oxidizer depletion.


How long can the second stage "wait" before performing a second (and I
presume final?) burn?


Speculation on ARocket is that the burn was canceled more because of the
NASA imposed rules to prevent anything from hitting ISS. Supposedly
this off-nominal situation was so far off nominal that it wasn't covered
by the analyses done for this reason. Because of this, they had to go
to the backup plan.

In the future, SpaceX (and NASA) might want to expand their analyses to
cover an off-nominal situation like this on the next flight. Ditching
an otherwise good satellite into a useless orbit is a bit of a shame
(for the paying customer).

Also, I'm still trying to come to grips with what apart from an
"according to common usage among the peanut gallery" "explosion" would
have caused those pressure relieving panels to blow. "Engine pressure
release" sounds a bit like describing a fire as an "exothermal event
with external charring." I think it was a great demonstration of the
Falcon9's resiliance but euphamisms (assuming they are indeed getting
used here) don't speak well towards organizational resiliance. Or
perhaps it is just my peanut-gallery understanding of terminology.


Speculation on ARocket (based on analysis of the video) is that the
combustion chamber must have been breached. This would qualify as
"engine pressure release", even though non-technical people would say
the combustion chamber "exploded".

Since the same non-technical people often (wrongly) say that Challenger
was destroyed by an "explosion", naturally SpaceX would not want to
encourage them to use that term. It's not correct and it's potentially
bad for their image.

The good news is that the first stage continued even with the failed
engine and Dragon made it into orbit successfully. The bad news is that
the secondary payload did not make it into the right orbit and SpaceX
has some failure analyses to do on the failed engine before the next
flight.

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
  #7  
Old October 9th 12, 10:54 PM posted to sci.space.history
snidely
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Posts: 1,303
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

Rick Jones used his keyboard to write :

So the second stage of the rocket system that has a first stage which
can supposedly "complete the mission" if it loses two engines,
ended-up without enough propellant to complete the mission?


Where did you get this from Jeff's posting? Upthread, he notes there
was fuel available, but that it wasn't used because off possible
conflict with ISS trsjectories.

/dps

--
Who, me? And what lacuna?


  #8  
Old October 9th 12, 11:27 PM posted to sci.space.history
Rick Jones
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Posts: 685
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

Snidely wrote:
Rick Jones used his keyboard to write :


So the second stage of the rocket system that has a first stage which
can supposedly "complete the mission" if it loses two engines,
ended-up without enough propellant to complete the mission?


Where did you get this from Jeff's posting? Upthread, he notes there
was fuel available, but that it wasn't used because off possible
conflict with ISS trsjectories.


I thought that I'd seen a mention of insufficient fuel somewhere (not
necessarily in this newsgroup), but could be mistaken.

rick jones
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  #9  
Old October 10th 12, 12:48 AM posted to sci.space.history
Rick Jones
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Posts: 685
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

Rick Jones wrote:
I thought that I'd seen a mention of insufficient fuel somewhere (not
necessarily in this newsgroup), but could be mistaken.


I think I got the impression from
http://news.cnet.com/8301-11386_3-57...ngine-failure/
though reading it again shows I may have read too much into that.

So, *did* the second stage have to burn longer on its first burn as
part of compensating for the loss of the first-stage engine? If the
second stage were where it was nominally supposed to be after the
first burn, with the nominally expected quantity of fuel and oxidizer
etc remaining, presumably it should have been in a state where the
second burn could be permitted. But the second burn was not
permitted, so doesn't that suggest that either the second stage was
not where it was nominally supposed to be, and/or didn't have the
nomninal quantity of remaining fuel/oxidizer? If so, was that then a
consequence of having to compensate for the first-stage engine-out
(goes to "Falcon 9 can complete the mission with a first-stage
engine-out"), or was there an additional problem, involving the second
stage more directly?

rick jones
--
No need to believe in either side, or any side. There is no cause.
There's only yourself. The belief is in your own precision. - Joubert
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
  #10  
Old October 10th 12, 01:48 PM posted to sci.space.history
Jeff Findley[_2_]
external usenet poster
 
Posts: 1,388
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

In article ,
says...

Jeff Findley wrote:
In article ,

says...
How long can the second stage "wait" before performing a second (and I
presume final?) burn?


Speculation on ARocket is that the burn was canceled more because of
the NASA imposed rules to prevent anything from hitting ISS.
Supposedly this off-nominal situation was so far off nominal that it
wasn't covered by the analyses done for this reason. Because of
this, they had to go to the backup plan.


So the second stage of the rocket system that has a first stage which
can supposedly "complete the mission" if it loses two engines,
ended-up without enough propellant to complete the mission? Or is the
second stage's lack of sufficent fuel/oxidizer for the burn not a
result of the first stage's loss of an engine?


The Falcon 9 first stage has nine engines (hence the origins of its
name). One first stage engine failed in a somewhat spectacular way. To
compensate, the first stage burned longer, but due to the lower thrust
of the first stage, it surely incurred more drag and gravity losses than
on a nominal launch. Because of the first stage losses, the second
stage must have also burned longer in order to make it into the proper
"parking" orbit for Dragon release. So, the launch was a success for
Dragon.

The second stage only has one engine, so burning longer left it with
less fuel than a nominal mission. This meant that there wasn't enough
fuel for the next burn. This burn would have placed the secondary
payload into its final orbit. This was at least a partial failure for
the secondary payload any way you look at it.

Unfortunately, because of the ISS constraint, SpaceX wasn't allowed to
perform any additional burn using the fuel remaining in the second
stage. So, the backup plan was initiated which released the secondary
payload into the parking orbit, which is a far cry from its intended
orbit.

If it weren't for the ISS constraint, SpaceX surely would have done the
second burn (likely to fuel depletion) in order to place the secondary
payload into as favorable of an orbit as they could. But they couldn't,
which is a shame for the secondary payload.

The bottom line is that this was a successful launch of the primary
payload (Dragon), but a nearly complete failed launch for the secondary
payload. Sucks to be a secondary payload when "stuff happens".

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
 




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