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Maximum Rate Shuttle Launches



 
 
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  #1  
Old June 11th 07, 02:31 AM posted to sci.space.shuttle,sci.space.policy
[email protected]
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Default Maximum Rate Shuttle Launches

Given a few extra billion dollars, and a year or two for preparation,
what sort of sustainable launch rate could the shuttle attain?

-Curious
-Charles Talleyrand

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  #4  
Old June 11th 07, 05:33 AM posted to sci.space.shuttle,sci.space.policy
Revision
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Posts: 98
Default Maximum Rate Shuttle Launches

Given a few extra billion dollars, and a year or two for preparation,
what sort of sustainable launch rate could the shuttle attain?


Well, let's toss out the money part .... that is looking at the problem
backwards.

Consider when a shuttle lands, it gets checked out, tweaked, new tank
fitted, SRBs stacked. So considering no anomalies this is going to take
a month. And with however many we have now, and allowing for some
schedule slippage, a launch per month is do-able. (Then you get the
invoice.)

Considering the operating scrutiny, budget limits, and so on, doing three
or four a year is a significant lauch rate.




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Posted via a free Usenet account from http://www.teranews.com

  #5  
Old June 11th 07, 06:41 AM posted to sci.space.shuttle,sci.space.policy
Charles Talleyrand
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Posts: 6
Default Maximum Rate Shuttle Launches

On Jun 10, 11:33 pm, "Revision" wrote:
Given a few extra billion dollars, and a year or two for preparation,
what sort of sustainable launch rate could the shuttle attain?


Well, let's toss out the money part .... that is looking at the problem
backwards.

Consider when a shuttle lands, it gets checked out, tweaked, new tank
fitted, SRBs stacked. So considering no anomalies this is going to take
a month. And with however many we have now, and allowing for some
schedule slippage, a launch per month is do-able. (Then you get the
invoice.)


That seems fine. But are there enough of the specialized machines to
build 24 SRBs per year? Can the launch pad support 1 launch per
month? Could the tank manufacturer build 12 tanks a year if you have
them a year's notice? What's the turn-around time on an orbiter,
assuming a willingness to pay lots of overtime, hire and train extra
staff, but expecting to suffer a normal amount of normal problems?

  #6  
Old June 11th 07, 07:06 AM posted to sci.space.shuttle,sci.space.policy
Fred J. McCall
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Posts: 5,736
Default Maximum Rate Shuttle Launches

Charles Talleyrand wrote:

:On Jun 10, 11:33 pm, "Revision" wrote:
: Given a few extra billion dollars, and a year or two for preparation,
: what sort of sustainable launch rate could the shuttle attain?
:
: Well, let's toss out the money part .... that is looking at the problem
: backwards.
:
: Consider when a shuttle lands, it gets checked out, tweaked, new tank
: fitted, SRBs stacked. So considering no anomalies this is going to take
: a month. And with however many we have now, and allowing for some
: schedule slippage, a launch per month is do-able. (Then you get the
: invoice.)
:
:
:That seems fine. But are there enough of the specialized machines to
:build 24 SRBs per year? Can the launch pad support 1 launch per
:month? Could the tank manufacturer build 12 tanks a year if you have
:them a year's notice? What's the turn-around time on an orbiter,
:assuming a willingness to pay lots of overtime, hire and train extra
:staff, but expecting to suffer a normal amount of normal problems?
:

The original vision called for 40 launches a year (with 5 orbiters, I
believe), with an assumption of simple ground operation.

In actuality, they'd be hard pressed to manage 8 flights a year (with
4 orbiters).

The only way to do better than 8-9 flights a year is use a different
vehicle.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw
  #7  
Old June 11th 07, 11:05 AM posted to sci.space.shuttle,sci.space.policy
Henry Spencer
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Posts: 2,170
Default Maximum Rate Shuttle Launches

In article ,
Fred J. McCall wrote:
The original vision called for 40 launches a year (with 5 orbiters, I
believe), with an assumption of simple ground operation.


They had backed off to 24 with four orbiters by the time of the Challenger
accident. In practice, flying 9 flights in 1985 was a strain, and the
push to step up the rate further contributed heavily to the accident.

In actuality, they'd be hard pressed to manage 8 flights a year (with
4 orbiters).


If I recall correctly, the post-Challenger assessment was that there was
nothing about the 9/year rate that would have been fundamentally hard to
sustain... given greater investment in spare parts, support facilities,
and operations manpower, plus some simplifications like actually enforcing
the rules about not making late changes in payload manifests. The
orbiters weren't the "long pole in the tent" for flight rate, except
insofar as shortage of spares made it hard to keep them all operational
simultaneously.

Note that the post-Challenger flight rate was substantially higher than it
is today -- I think it was 8/year when everything went right. The later
reductions were for financial reasons, not because there is any deep
obstacle to the higher rate.

If (dim) memory serves, the fundamental limit set by having only four
orbiters was thought to be (in post-Challenger hindsight) something like
15-20/year. That rate would require quite a few more facilities -- e.g.,
two or three more of the big simulators at JSC -- and a lot of money. You
could probably go a bit higher if you first made substantial orbiter
changes, e.g. a nontoxic-propellants RCS/OMS system to remove the
bottlenecks in the orbiter processing that arise from having to clear the
area every time work even comes close to those systems.

Building up to even the maximum three-unmodified-orbiters rate *now* would
be extremely expensive, and would take several years even with unlimited
funding, because a lot of crucial items are long out of production, and it
takes time to build new facilities and train new staff.

Plus there is that little problem that at such rates, you're probably only
a few years from another loss-of-orbiter accident. (One of the more
interesting post-Challenger reports -- from OTA? I forget -- concluded
that ongoing orbiter production was mandatory for reliable long-term
operations, especially if projects like the space station needed a
guaranteed minimum fleet size. This was not what people wanted to hear
just then, so that report was quietly shelved...)
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |
  #8  
Old June 11th 07, 12:10 PM posted to sci.space.shuttle,sci.space.policy
Ian Parker
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Posts: 2,554
Default Maximum Rate Shuttle Launches

On 11 Jun, 07:06, Fred J. McCall wrote:
Charles Talleyrand wrote:

:On Jun 10, 11:33 pm, "Revision" wrote:
: Given a few extra billion dollars, and a year or two for preparation,
: what sort of sustainable launch rate could the shuttle attain?
:
: Well, let's toss out the money part .... that is looking at the problem
: backwards.
:
: Consider when a shuttle lands, it gets checked out, tweaked, new tank
: fitted, SRBs stacked. So considering no anomalies this is going to take
: a month. And with however many we have now, and allowing for some
: schedule slippage, a launch per month is do-able. (Then you get the
: invoice.)
:
:
:That seems fine. But are there enough of the specialized machines to
:build 24 SRBs per year? Can the launch pad support 1 launch per
:month? Could the tank manufacturer build 12 tanks a year if you have
:them a year's notice? What's the turn-around time on an orbiter,
:assuming a willingness to pay lots of overtime, hire and train extra
:staff, but expecting to suffer a normal amount of normal problems?
:

The original vision called for 40 launches a year (with 5 orbiters, I
believe), with an assumption of simple ground operation.

In actuality, they'd be hard pressed to manage 8 flights a year (with
4 orbiters).

The only way to do better than 8-9 flights a year is use a different
vehicle.

All this was deducible during the DESIGN stage. Yet those who were "in
the know" promised us cheap access to space. They knew all along that
this was poppycock. Can you wonder that we do not believe everything
that is trotted out now?


- Ian Parker

  #9  
Old June 11th 07, 01:45 PM posted to sci.space.shuttle,sci.space.policy
[email protected]
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Posts: 1,516
Default Maximum Rate Shuttle Launches

Today the aged fleet makes it impossible. Just look at the pressure
tanks any one of which can go BOOM at any time

Stuff thats old gets all sorts of wierd problems and parts are no
longer available, manufacturers out of business.

There isnt enough time by 2010 to safely finish ISS.

No doubt NASA is signing waivers for lots of bad day creators.

ISS will be called complete with our next accident

  #10  
Old June 11th 07, 02:17 PM posted to sci.space.shuttle,sci.space.policy
Fred J. McCall
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Posts: 5,736
Default Maximum Rate Shuttle Launches

Ian Parker wrote:

:On 11 Jun, 07:06, Fred J. McCall wrote:
:
: The original vision called for 40 launches a year (with 5 orbiters, I
: believe), with an assumption of simple ground operation.
:
: In actuality, they'd be hard pressed to manage 8 flights a year (with
: 4 orbiters).
:
: The only way to do better than 8-9 flights a year is use a different
: vehicle.
:
:
:All this was deducible during the DESIGN stage. Yet those who were "in
:the know" promised us cheap access to space. They knew all along that
:this was poppycock. Can you wonder that we do not believe everything
:that is trotted out now?
:

All those people are long retired and probably dead by now, Ian...


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
 




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