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Falcon Sir Lauch-A-Lot?



 
 
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  #1  
Old March 21st 07, 01:38 AM posted to sci.space.policy,sci.space.history
Joe Strout
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Posts: 972
Default Falcon Sir Lauch-A-Lot?

In article ,
Pat Flannery wrote:

Well, if nothing else, it's showing the on-time launch reliability
demonstrated by the Shuttle in a privately funded booster.


To be fair, they said right up front that multiple aborts were likely,
given the extremely numerous (and probably erring on the side of
paranoid) safety checks added since last year. It's not surprising if
it takes a few tries to shake out all the unintended consequences.

I still don't think that pre-launch test firing of a engine with an
ablative combustion chamber lining is a good idea.


I can see your point. But presumably you know how much it's going to
ablate in the test, and how much you safely need for the real launch,
right?

Best,
- Joe
  #2  
Old March 21st 07, 02:27 AM posted to sci.space.policy,sci.space.history
Pat Flannery
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Default Falcon Sir Lauch-A-Lot?

Well, if nothing else, it's showing the on-time launch reliability
demonstrated by the Shuttle in a privately funded booster.
I still don't think that pre-launch test firing of a engine with an
ablative combustion chamber lining is a good idea.

Pat
  #3  
Old March 21st 07, 03:47 AM posted to sci.space.policy,sci.space.history
Geoffrey A. Landis
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Default Falcon Sir Lauch-A-Lot?

On Mar 20, 8:38 pm, Joe Strout wrote:
Pat Flannery wrote:
Well, if nothing else, it's showing the on-time launch reliability
demonstrated by the Shuttle in a privately funded booster.


To be fair, they said right up front that multiple aborts were likely,
given the extremely numerous (and probably erring on the side of
paranoid) safety checks added since last year.


To be fair, "numerous safety checks" and "probably erring on the side
of paranoid" are precisely the reason that the shuttle launches get
pushed back.

If you are going to be cautious, sometimes you will stop a launch.

--
Geoffrey A. Landis
http://www.sff.net/people/geoffrey.landis

  #4  
Old March 21st 07, 04:38 AM posted to sci.space.policy,sci.space.history
richard schumacher
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Posts: 191
Default Falcon Sir Lauch-A-Lot?


Did anyone else get creeped out by the sight of the second stage nozzle
glowing orange hot? Yeesh! I hope they remembered that it gets less
cooling in vacuum (that is, in use) than in air (during tests).
  #6  
Old March 21st 07, 07:49 AM posted to sci.space.policy,sci.space.history
Alex Terrell
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Posts: 492
Default Falcon Sir Lauch-A-Lot?

On 21 Mar, 01:27, Pat Flannery wrote:
Well, if nothing else, it's showing the on-time launch reliability
demonstrated by the Shuttle in a privately funded booster.
I still don't think that pre-launch test firing of a engine with an
ablative combustion chamber lining is a good idea.

Pat


Just woke up - read all this and can't decide whether the Falcon 1
flight was a success or whether it was a failure with a positive
spin.

"The second stage didn't achieve full orbital velocity, due to a roll
excitation late in the burn, but that should be a comparatively easy
fix once we examine the flight data."

What's a roll excitation, and why doesn't the flight control software
compensate for this?

Perhaps this will mean more to me after a cup of coffee.

  #7  
Old March 21st 07, 08:26 AM posted to sci.space.policy,sci.space.history
Pat Flannery
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Posts: 18,465
Default Falcon Sir Lauch-A-Lot?



Joe Strout wrote:

To be fair, they said right up front that multiple aborts were likely,
given the extremely numerous (and probably erring on the side of
paranoid) safety checks added since last year. It's not surprising if
it takes a few tries to shake out all the unintended consequences.


Well, whether the satellite went into orbit or not, they did get the
thing into space... and had a successful first-stage burn, which is more
than the Soviet N1 ever did, and I applaud them for that.

Pat

  #8  
Old March 21st 07, 02:41 PM posted to sci.space.policy,sci.space.history
Jeff Findley
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Default Falcon Sir Lauch-A-Lot?


"Pat Flannery" wrote in message
...
Well, if nothing else, it's showing the on-time launch reliability
demonstrated by the Shuttle in a privately funded booster.


You'd have to compare Falcon I flight 1 and 2 to STS-1 and STS-2. Here's a
list of STS-1 anomolies (some of them damn scary):
http://www.jsc.nasa.gov/news/columbia/anomaly/STS1.pdf

These problems had to be addressed before STS-2.

STS-1 launched on April 12, 1981 and STS-2 launched November 12, 1981.
Falcon 1 demo flight 1 launched on November 25, 2005 and demo flight 2 on
March 20, 2007. So it looks like Falcon 1 was a bit faster in getting to
its second launch than Columbia, but that's apples and oranges since
Columbia was "reusable".

I still don't think that pre-launch test firing of a engine with an
ablative combustion chamber lining is a good idea.


If you've got enough margin in the design, it's really not a bad idea.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)


  #9  
Old March 21st 07, 04:09 PM posted to sci.space.policy,sci.space.history
richard schumacher
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Posts: 191
Default Falcon Sir Lauch-A-Lot?

In article .com,
"Alex Terrell" wrote:

What's a roll excitation, and why doesn't the flight control software
compensate for this?


Because the control system is not perfect. They'll fix it. This is why
people test things.
  #10  
Old March 21st 07, 06:36 PM posted to sci.space.policy,sci.space.history
Jake McGuire
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Posts: 99
Default Falcon Sir Lauch-A-Lot?

On Mar 21, 6:41 am, "Jeff Findley"
wrote:
"Pat Flannery" wrote in message

...

Well, if nothing else, it's showing the on-time launch reliability
demonstrated by the Shuttle in a privately funded booster.


You'd have to compare Falcon I flight 1 and 2 to STS-1 and STS-2. Here's a
list of STS-1 anomolies (some of them damn scary):http://www.jsc.nasa.gov/news/columbia/anomaly/STS1.pdf

These problems had to be addressed before STS-2.

STS-1 launched on April 12, 1981 and STS-2 launched November 12, 1981.
Falcon 1 demo flight 1 launched on November 25, 2005 and demo flight 2 on
March 20, 2007. So it looks like Falcon 1 was a bit faster in getting to
its second launch than Columbia, but that's apples and oranges since
Columbia was "reusable".


Either your math is off or there's a typo here - 11/2005 to 3/2007 is
16 months, while 4/1981 to 11/1981 is seven.

-jake

 




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