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



 
 
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  #11  
Old October 10th 12, 03:28 PM posted to sci.space.history
Dean
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Posts: 323
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

On Monday, October 8, 2012 6:11:08 PM UTC-4, 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/



rick jones

--

the road to hell is paved with business decisions...

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...


That's a nice explanation. Now as far as that secondary payload? Is it totally useless? If so, would there be any insurance coverage?
  #12  
Old October 10th 12, 07:41 PM posted to sci.space.history
Brad Guth[_3_]
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Posts: 15,175
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

On Oct 10, 7:28*am, Dean wrote:
On Monday, October 8, 2012 6:11:08 PM UTC-4, 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/


rick jones


--


the road to hell is paved with business decisions...


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...


That's a nice explanation. *Now as far as that secondary payload? *Is it totally useless? *If so, would there be any insurance coverage?


For a hefty fee and/or substantial deductible, anything can be insured
or bet upon. Possibly they bought a 50% coverage policy for a million
bucks.
  #13  
Old October 13th 12, 01:57 PM posted to sci.space.history
David Spain
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Posts: 2,901
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

On 10/10/2012 8:48 AM, Jeff Findley wrote:
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.

Not exactly the way I read it over on Arocket. IIRC I think the issue was not
that there was not enough fuel to do the final orbit burn for the secondary payload
but that the amount remaining after Dragon insertion (because of the extended 2nd
stage burn due to loss of 1 F9 engine) was below the minimums needed to assure success.
In other words it was below the 'reserve' allocated to do that to guarantee no
problems with orbital position relative to ISS. After reading that I presumed that
'reserve' was an engineering estimate that would normally be conservative and thus beyond
what was actually required. Admittedly a guess on my part.

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.

I don't think to depletion would have been necessary, but likely would have
left the 2nd stage with less than what was estimated to be safe (for ISS).

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".



Yup. However, it is also an opportunity. As a paying secondary customer, maybe in the future
I can get a break on my bill because of this higher risk than say, I might pay to be a secondary
payload on a mission of less risk, like a GEO sat insertion primary payload which has no risk
of collision with ISS or any other manned object?

Jeff


Dave **Ebeneezer** Scrooge


  #14  
Old October 14th 12, 10:21 AM posted to sci.space.history
Robert Clark[_2_]
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Posts: 30
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

On Oct 9, 6:27*pm, Rick Jones wrote:
...
--
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?


Works well enough on Jeopardy.

Bob Clark

  #15  
Old October 14th 12, 02:45 PM posted to sci.space.history
Greg \(Strider\) Moore
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Posts: 790
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

"Robert Clark" wrote in message
...

On Oct 9, 6:27 pm, Rick Jones wrote:
...
--
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?


Works well enough on Jeopardy.


Great. And when I can win thousands of dollars posting to Usenet, please
let me know.



Bob Clark



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

  #16  
Old October 15th 12, 02:10 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 , nospam@
127.0.0.1 says...

On 10/10/2012 8:48 AM, Jeff Findley wrote:
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.


Not exactly the way I read it over on Arocket. IIRC I think the issue was not
that there was not enough fuel to do the final orbit burn for the secondary payload
but that the amount remaining after Dragon insertion (because of the extended 2nd
stage burn due to loss of 1 F9 engine) was below the minimums needed to assure success.
In other words it was below the 'reserve' allocated to do that to guarantee no
problems with orbital position relative to ISS. After reading that I presumed that
'reserve' was an engineering estimate that would normally be conservative and thus beyond
what was actually required. Admittedly a guess on my part.

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.


I don't think to depletion would have been necessary, but likely would have
left the 2nd stage with less than what was estimated to be safe (for ISS).


From newspacewatch.com:

NASA had required that a restart of the upper stage only
occur if there was a very high probability (over 99%) of
fully completing the second burn. While there was
sufficient fuel on board to do so, the liquid oxygen on
board was only enough to achieve a roughly 95% likelihood
of completing the second burn, so Falcon 9 did not attempt
a restart.

From this, it seems that there was a 95% chance of the burn completing.
The remaining 5% chance was the case that the LOX would have burned to
depletion.

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".


Yup. However, it is also an opportunity. As a paying secondary customer, maybe in the future
I can get a break on my bill because of this higher risk than say, I might pay to be a secondary
payload on a mission of less risk, like a GEO sat insertion primary payload which has no risk
of collision with ISS or any other manned object?


It would be interesting to find out what the cost for this flight was
since the secondary payloads are taking a greater risk than the primary,
especially when the primary involves NASA and ISS.

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
  #17  
Old October 16th 12, 05:58 AM posted to sci.space.history
snidely
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Posts: 1,303
Default Unplanned engine-out resiliance test for CRS-1 Falcon 9?

Jeff Findley explained :

[David Spain, although Jeff's newsreader may have been confused about that]
Yup. However, it is also an opportunity. As a paying secondary customer,
maybe in the future I can get a break on my bill because of this higher risk
than say, I might pay to be a secondary payload on a mission of less risk,
like a GEO sat insertion primary payload which has no risk of collision with
ISS or any other manned object?


It would be interesting to find out what the cost for this flight was
since the secondary payloads are taking a greater risk than the primary,
especially when the primary involves NASA and ISS.


Quote from NBCNews.com:

quote
Satellite messaging service provider Orbcomm on Oct. 11 said its
prototype second-generation satellite, launched Oct. 7 into a bad orbit
by a Space Exploration Technologies Corp. (SpaceX) Falcon 9 rocket, had
fallen out of orbit but had provided enough data to proceed with the
launch of the full constellation starting next year.
/quote
url=http://www.msnbc.msn.com/id/49403078/ns/technology_and_science-space/#.UHzor8XA-So

You may have seen the news at other sites, as well.

/dps

--
Who, me? And what lacuna?


  #19  
Old October 24th 12, 09:24 PM posted to sci.space.history
Jeff Findley[_2_]
external usenet poster
 
Posts: 1,388
Default Should SpaceX use larger but fewer engines for reliability on the Falcon 9?

In article ,
says...

Jeff Findley wrote:
In article ,
says...
I find it mildly amusing that you think a "large fireball" is not
nearly as hazardous as an "explosion".


Because it's not as hazardous, especially when you have a launch escape
system in place to get you away from the fireball.


As a check, since I have peanut-gallery difficulty with fireball vs
explosion Was it a large fireball that enveloped (?) Challenger?


Yes, a fireball enveloped Challenger when the LH2 dome on the external
tank failed and the LH2 was released "all at once". But, but the
fireball did NOT destroy Challenger. The Challenger Accident
Investigation Board goes into excruciating detail about the sequence of
events (you can find this on-line). But, the super short executive
summary is that when the shuttle stack broke apart, Challenger pitched
up in the high velocity air-stream and was literally ripped apart by
aerodynamic forces far beyond what it was designed to withstand. The
very visible fireball had nothing to do with Challenger breaking into
pieces.

Unfortunately, to this day, many refer to the "Challenger explosion",
even though there was never an explosion.


Let's put it another way. On Mythbusters when they use lots of gasoline
to create a big orange fireball, that's NOT an explosion. When they use
a high energy explosive, there is usually very little in the way of a
"fireball", but there is *always* a well defined pressure wave that
shows up in the high speed video. That pressure wave is the telltale
sign that you've got a true explosion, not a fireball.

There was actually an episode where they compared the results of a
Hollywood style (gasoline) fireball to the results of a true explosion
on a car. The Hollywood style fireball certainly looked impressive, and
burned the car, but the explosion literally ripped the car to pieces
without the big orange fireball that looks so good on "the big screen".

trimming previous and now extraneous text, done well at least, is a
good thing...


On occasion, I'm guilty of not trimming enough.

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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