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SpaceX Launch Update



 
 
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  #1  
Old December 10th 05, 02:06 PM posted to sci.space.policy
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Default SpaceX Launch Update

FWIW Got this from the SpaceX email list:

Launch Date
The new launch date is approximately December 20, depending on when the
Missile Defense Agency testing is complete. As soon as we have a firm
time, it will be posted on the SpaceX website.

Liquid Oxygen
Regarding liquid oxygen (LOX) supplies, we expect to have enough on
hand this time to fill the rocket four or five times over. This should
account for almost any issue with a particular storage tank as well as
an extended hold on the pad. There is an engineering term known as a
s*load. I have asked that we have at least two s*loads on hand in case
one s*load is not enough.

We chartered a C-17 to fly two of our empty high quality LOX containers
to Hawaii, sourced another high quality LOX container on Hawaii and put
all three on the barge to Kwajalein. In addition, our LOX plant on
Kwajalein has been repaired and is producing LOX on island again.

Some might be wondering why we were so dumb as to run out of LOX on a
remote tropical island on the last launch attempt.
Believe me, we tried hard to avoid it, but several issues conspired to
create the problem:
* The additional month of Merlin testing resulted in
additional LOX boil-off on island.
Even though it is stored in vacuum jacketed containers,
LOX at -300F degrees does not like being on a tropical
island at 85F.
*The SpaceX LOX plant on island broke down a few weeks prior
to launch,
which meant we could not top up.
*We ordered replacement LOX from Hawaii, but the container
quality was poor,
so only 20% of what we ordered actually arrived.
*Ground winds were unusually high on launch day,
which amplifies the boil-off rate significantly,
since the Falcon's first stage LOX tank is uninsulated.
*All of the above would not have mattered if our final
storage tank did not have a small,
manual vent valve incorrectly in the open position.
Somewhat
agonizingly, we were only a few percent away from being
full. We just needed a little sip from the last tank.
*After a while, we were able to close the vent and fill the
vehicle's LOX tanks.
However, we use LOX to chill our onboard helium and the
absence of ground
LOX to do so resulted in the helium heating up and venting
back to storage.
In the end, we did not have enough LOX to stay filled on the
rocket and chill &
pressurize the helium.

Engine Computer
The engine computer reboot anomaly was definitively traced to a ground
power problem. Importantly, this would have had no effect on flight,
since we switch to vehicle power before the autosequence begins. The
reason it cropped up at Kwajalein was that the higher load on the
longer umbilical (three times longer than in prior tests) coupled with
high temperatures in Kwajalein resulted in increased resistance in the
ground umbilical. This was just enough to lower the voltage below
minimums and cause an engine computer reset when drawing maximum power.
The same max power test was repeated on internal vehicle batteries
with no problem at all.
This problem has been solved by slightly increasing voltage on the
ground umbilical.

--Elon--


Well we know the whole story, do we cut them some slack for this?

Just my $0.02

Space Cadet

  #2  
Old December 10th 05, 03:14 PM posted to sci.space.policy
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Default SpaceX Launch Update


Space Cadet wrote:
FWIW Got this from the SpaceX email list:

Launch Date
The new launch date is approximately December 20, depending on when the
Missile Defense Agency testing is complete. As soon as we have a firm
time, it will be posted on the SpaceX website.

This sounds familiar. Will launch as soon as the Pentagon has managed
to launch something else.

Lots of food for the conspiracy theorists - Spacex will need a sea
launch soon.

  #3  
Old December 10th 05, 06:51 PM posted to sci.space.policy
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Default SpaceX Launch Update

"Space Cadet" wrote:

Some might be wondering why we were so dumb as to run out of LOX on a
remote tropical island on the last launch attempt.
Believe me, we tried hard to avoid it, but several issues conspired to
create the problem:
* The additional month of Merlin testing resulted in
additional LOX boil-off on island.


Huh? What additional testing was needed?

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
  #4  
Old December 10th 05, 07:08 PM posted to sci.space.policy
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Default SpaceX Launch Update


Derek Lyons wrote:
"Space Cadet" wrote:

Some might be wondering why we were so dumb as to run out of LOX on a
remote tropical island on the last launch attempt.
Believe me, we tried hard to avoid it, but several issues conspired to
create the problem:
* The additional month of Merlin testing resulted in
additional LOX boil-off on island.


Huh? What additional testing was needed?


SpaceX suffered a Merlin engine failure on its Texas test
stand back on September 7, 2005. The additional testing
was presumably with another engine sent to Texas. SpaceX
delayed the Kwaj launch (originally planned for late September)
while this testing was underway, which caused more of the
LOX stored at Kwaj/Omelek to boil off than would have if they
had made the original launch date.

A tangled web, space launch is.

- Ed Kyle

  #5  
Old December 10th 05, 09:34 PM posted to sci.space.policy
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Default SpaceX Launch Update


Ed Kyle wrote:

SpaceX suffered a Merlin engine failure on its Texas test
stand back on September 7, 2005. The additional testing
was presumably with another engine sent to Texas. SpaceX
delayed the Kwaj launch (originally planned for late September)
while this testing was underway, which caused more of the
LOX stored at Kwaj/Omelek to boil off than would have if they
had made the original launch date.

A tangled web, space launch is.

- Ed Kyle


After many launch delays, the black and white Columbia came to be known
as the "Penguin" (a flightless bird).

Maybe it's time to change the "Falcon" to........ (pick one):

-Ostrich
-Rhea
-Cassowary
-Emu
-Kiwi
-Kakapo
-Takahe
-Tinamou
-Moa
-Dodo

;-)

Rusty

  #7  
Old December 10th 05, 11:01 PM posted to sci.space.policy
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Default SpaceX Launch Update

"Ed Kyle" wrote:


Derek Lyons wrote:
"Space Cadet" wrote:

Some might be wondering why we were so dumb as to run out of LOX on a
remote tropical island on the last launch attempt.
Believe me, we tried hard to avoid it, but several issues conspired to
create the problem:
* The additional month of Merlin testing resulted in
additional LOX boil-off on island.


Huh? What additional testing was needed?


SpaceX suffered a Merlin engine failure on its Texas test
stand back on September 7, 2005. The additional testing
was presumably with another engine sent to Texas. SpaceX
delayed the Kwaj launch (originally planned for late September)
while this testing was underway, which caused more of the
LOX stored at Kwaj/Omelek to boil off than would have if they
had made the original launch date.

A tangled web, space launch is.


OK, that makes sense. I parsed that (incorrectly) as 'an additional
month of testing [at the launch site]'.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
  #8  
Old December 11th 05, 01:11 AM posted to sci.space.policy
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Default SpaceX Launch Update

"Ed Kyle" wrote in message
oups.com...

SpaceX suffered a Merlin engine failure on its Texas
test stand back on September 7, 2005. The
additional testing was presumably with another engine
sent to Texas. SpaceX delayed the Kwaj launch
(originally planned for late September) while this
testing was underway, which caused more of the
LOX stored at Kwaj/Omelek to boil off than would
have if they had made the original launch date.


Personally I am not so concerned by a few delays, a few failures even,
as long as they make fast, cheap and steady progress towards success.

One of my current concerns is that SpaceX will become so risk adverse
that they will attempt success at any price, becoming just another
expensive launch system. Some of their current failure avoidance
measures do seem to be overkill.

I think one of the critical lessons from this development has been that
such a low cost launch system must be designed to avoid third party
launch schedule limitations. A serious development needs to be able to
attempt a launch near every day, SpaceX are not managing once a month.
They are now throwing money at the problem to try and compensate - not
good.

Pete.


  #9  
Old December 11th 05, 05:01 PM posted to sci.space.policy
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Default SpaceX Launch Update

Pete Lynn wrote:

I think one of the critical lessons from this development has been that
such a low cost launch system must be designed to avoid third party
launch schedule limitations. A serious development needs to be able to
attempt a launch near every day, SpaceX are not managing once a month.
They are now throwing money at the problem to try and compensate - not
good.


It appears more and more likely that commercial launch needs
to decouple from DoD launch sites to become practical. But
SpaceX is, of course, doing most of its launches for DoD, so
the delays are self-inflicted by the customer in that sense. I
wonder who pays for the cost of range delays?

- Ed Kyle

 




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