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How many shuttle flights per year without Challenger accident?



 
 
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  #11  
Old February 14th 12, 08:15 PM posted to sci.space.history
Mike DiCenso
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Posts: 150
Default How many shuttle flights per year without Challenger accident?

On Feb 11, 1:55*pm, Brian Thorn wrote:
On 2012-02-11 18:44:14 +0000, Val Kraut said:

But even if all went well as planned, Enterprise was refurbished for
space (but is was too heavy),


Enterprise would have been about the same as Columbia, maybe a little
lighter. It could easily have handled Spacelab and HS-376 deployment
missions, just as Columbia did. And note that despite being the
heaviest Orbiter, Columbia actually launched the heaviest payload of
the Shuttle program: the Chandra AXAF/IUS. But everything useful was
yanked out of Enterprise and installed in Challenger, so there really
was no point to refurbishing Enterprise once the decision was made to
move to STA-099 (renamed OV-099 Challenger) in 1978.


Enterprise was studied several times for refurbishment to spaceworth
condition. The last time was in 1995-1996 as an automated freighter
for heavy-lift space station missions. But as always, the issue and
cost of taking Enterprise apart as well as shipping everything back to
the vendors for rehab always got in the way. Lucky for NASA that it
took the opportunity to invest in the structural spares while building
Discovery and Atlantis that allowed Endeavour to be built.

The interesting thing about all this alternate universe thinking is
what would have happened, if no Challenger accident occured, and then
Buran and Energia came online in 1989.
-Mike
  #12  
Old February 14th 12, 08:21 PM posted to sci.space.history
Mike DiCenso
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Posts: 150
Default How many shuttle flights per year without Challenger accident?

On Feb 12, 10:38*am, Brian Thorn wrote:
On 2012-02-11 18:53:22 +0000, Val Kraut said:

" In retrospect we know that the O-ring issue that destroyed Challenger
was inevitable. It had almost happened in earlier flights and would
likely have happened on some winter day sooner or later.


Supposedly there were partial burn throughs on recovered boosters - but
NASA didn't wake up to the real potential until they actually lost a
vehicle. There was an interesting article on the mind set people get
into - Hey worked the last 24 times we did it - we're on a roll!


Not "supposedly", it is well documented. My point is that STS-51L
nearly got away with it. The o-ring failure did not cause the disaster
alone. Had the windshear at T+55 seconds or so not reopened the leak
(this was the strongest windshear the Shuttle has ever experienced,
before or after Challenger), Challenger might have squeaked by and
survived. But that level of damage, with *both* o-rings having failed
(a first) would certainly have given the engineers the ammunition they
needed to suspend flights until a fix could be implemented. NASA would
have screamed bloody murder about missing the Galileo and ISPM
deadlines, but they would have been out of their "the backups kept us
safe" counter-arguments. The engineers would finally have their
evidence that the design was unsafe, which is what they didn't have in
hand on the night of January 27-28, 1986.

An interesting what-if.


There are other technical issues that would've slowed flight rates or
caused a launch failure. In hindsight, the ET foam loss from the bipod
ramp at those flight rates could have caused a loss of an orbiter as
happened eventually to Columbia. The early SSMEs were another
problematic issue with turbine blade cracks and so on.
-Mike
  #13  
Old February 14th 12, 10:03 PM posted to sci.space.history
Bob Haller
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Posts: 3,197
Default How many shuttle flights per year without Challenger accident?

On Feb 14, 2:15*pm, Mike DiCenso wrote:
On Feb 11, 1:55*pm, Brian Thorn wrote:

On 2012-02-11 18:44:14 +0000, Val Kraut said:


But even if all went well as planned, Enterprise was refurbished for
space (but is was too heavy),


Enterprise would have been about the same as Columbia, maybe a little
lighter. It could easily have handled Spacelab and HS-376 deployment
missions, just as Columbia did. And note that despite being the
heaviest Orbiter, Columbia actually launched the heaviest payload of
the Shuttle program: the Chandra AXAF/IUS. But everything useful was
yanked out of Enterprise and installed in Challenger, so there really
was no point to refurbishing Enterprise once the decision was made to
move to STA-099 (renamed OV-099 Challenger) in 1978.


Enterprise was studied several times for refurbishment to spaceworth
condition. The last time was in 1995-1996 as an automated freighter
for heavy-lift space station missions. But as always, the issue and
cost of taking Enterprise apart as well as shipping everything back to
the vendors for rehab always got in the way. Lucky for NASA that it
took the opportunity to invest in the structural spares while building
Discovery and Atlantis that allowed Endeavour to be built.

The interesting thing about all this alternate universe thinking is
what would have happened, if no Challenger accident occured, and then
Buran and Energia came online in 1989.
-Mike


NASA should of made enterprise flight worthy, at least as a automated
freight hauler.

this would of brought lots of support for nasa and shuttles, remants
of this may have kept the program going even today. if enterprise
would of been flown automated the remaing orbiters could be too.

even with the columbia loss the program may have survived
  #14  
Old February 15th 12, 12:50 AM posted to sci.space.history
Brian Thorn[_2_]
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Posts: 2,266
Default How many shuttle flights per year without Challenger accident?

On 2012-02-14 19:06:13 +0000, Mike DiCenso said:

Agreed, though SLC-6 would have likely put a huge damper on things for
a while once the actual fueled testing of Columbia at that facility
revealed the flaws there.


I think that problem was trumped up by an Air Force that wanted out of
Shuttle at all costs. This would not have caused significant launch
delays.

No. External Tank production would probably have peaked around 18 per
year. Michoud could handle *a little more, but I doubt they would have
really pushed that hard. They'd have reduced the flight rate to keep
things under control.


They'd have had no choice, looking back on it. There were other
technical issues that would have forced delays or flight rate
reduction or caused a catastrophic loss.


I really don't think any of the other problems rose to the level of the
SRB field joint flaws, which had been showing signs of failure since
STS-2. The other issues, like the Quick Disconnect, were theoretical or
laboratory problems only, not actually seen in the real world. Fixes
could have been implemented over time, just as the SSME and brake
improvements were pre- and post-Challenger.

The biggest threat to flight rate was the cannibalization and spare
parts issue, but as I wrote, that could have been resolved during the
say, one year standdown while the field joint heaters are implemented,
pending the full capture-feature redesign to follow a year or two later.


*If not that many, a dozen? 15?


Probably, if they funded a third OPF at KSC (without sacrificing SLC-6.)

Would the agency order a
fifth shuttle with such demand?


No, they would have backed out of the commercial market anyway,
relieving pressure on the 24-per-year goal. Arianespace would have
taken more commercial payloads regardless of Challenger.


Why? STS had huge cargo capacity for most of the then existing
satellite classes. Just load up a bunch of satellites into one mission
as was done for STS-41-D.


It was proving complicated to get all the payloads ready at the same
time. 41D itself was a an abberation caused by the cancelation of 41E
(or was it 41F?) leading to that flight being combined with 41D after
the RSLS abort in June. This is a continuing problem even today for
Ariane 5, which is why all indications are that Ariane 6 will be an
EELV-like one-at-a-time launcher. I suspect that even without
Challenger, Shuttle would have seen a major decline in commercial
payload launches, and NASA would not have complained all that much
about Ariane 4 taking that business. Congress would have complained
about the higher costs due to lower flight rate, but NASA would just
have said "Sorry, Arianespace is underbidding us" and quietly walked
away.

Brian
  #15  
Old February 15th 12, 02:56 AM posted to sci.space.history
Bob Haller
external usenet poster
 
Posts: 3,197
Default How many shuttle flights per year without Challenger accident?

On Feb 14, 6:50*pm, Brian Thorn wrote:
On 2012-02-14 19:06:13 +0000, Mike DiCenso said:



Agreed, though SLC-6 would have likely put a huge damper on things for
a while once the actual fueled testing of Columbia at that facility
revealed the flaws there.


I think that problem was trumped up by an Air Force that wanted out of
Shuttle at all costs. This would not have caused significant launch
delays.

No. External Tank production would probably have peaked around 18 per
year. Michoud could handle *a little more, but I doubt they would have
really pushed that hard. They'd have reduced the flight rate to keep
things under control.


They'd have had no choice, looking back on it. There were other
technical issues that would have forced delays or flight rate
reduction or caused a catastrophic loss.


I really don't think any of the other problems rose to the level of the
SRB field joint flaws, which had been showing signs of failure since
STS-2. The other issues, like the Quick Disconnect, were theoretical or
laboratory problems only, not actually seen in the real world. Fixes
could have been implemented over time, just as the SSME and brake
improvements were pre- and post-Challenger.

The biggest threat to flight rate was the cannibalization and spare
parts issue, but as I wrote, that could have been resolved during the
say, one year standdown while the field joint heaters are implemented,
pending the full capture-feature redesign to follow a year or two later.



*If not that many, a dozen? 15?


Probably, if they funded a third OPF at KSC (without sacrificing SLC-6..)


Would the agency order a
fifth shuttle with such demand?


No, they would have backed out of the commercial market anyway,
relieving pressure on the 24-per-year goal. Arianespace would have
taken more commercial payloads regardless of Challenger.


Why? STS had huge cargo capacity for most of the then existing
satellite classes. Just load up a bunch of satellites into one mission
as was done for STS-41-D.


It was proving complicated to get all the payloads ready at the same
time. 41D itself was a an abberation caused by the cancelation of 41E
(or was it 41F?) leading to that flight being combined with 41D after
the RSLS abort in June. This is a continuing problem even today for
Ariane 5, which is why all indications are that Ariane 6 will be an
EELV-like one-at-a-time launcher. I suspect that even without
Challenger, Shuttle would have seen a major decline in commercial
payload launches, and NASA would not have complained all that much
about Ariane 4 taking that business. Congress would have complained
about the higher costs due to lower flight rate, but NASA would just
have said "Sorry, Arianespace is underbidding us" and quietly walked
away.

Brian


well the original plans for KSC included pad 39C as a matter of fact i
have seen a photo of a sign with C included.

perhaps a additional pad would of been built?
  #16  
Old February 15th 12, 05:48 PM posted to sci.space.history
Brian Thorn[_2_]
external usenet poster
 
Posts: 2,266
Default How many shuttle flights per year without Challenger accident?

On 2012-02-15 01:56:55 +0000, bob haller said:

It was proving complicated to get all the payloads ready at the same
time. 41D itself was a an abberation caused by the cancelation of 41E
(or was it 41F?) leading to that flight being combined with 41D after
the RSLS abort in June. This is a continuing problem even today for
Ariane 5, which is why all indications are that Ariane 6 will be an
EELV-like one-at-a-time launcher. I suspect that even without
Challenger, Shuttle would have seen a major decline in commercial
payload launches, and NASA would not have complained all that much
about Ariane 4 taking that business. Congress would have complained
about the higher costs due to lower flight rate, but NASA would just
have said "Sorry, Arianespace is underbidding us" and quietly walked
away.

Brian


well the original plans for KSC included pad 39C as a matter of fact i
have seen a photo of a sign with C included.


They actually planned four pads at KSC. Four of everything, in fact:

Four High Bays in the Vehicle Assembly Building.
Four Mobile Launchers.
Four Firing Rooms in the Launch Control Center.
Four Launch Pads.

This was because originally they were expecting Earth Orbit Rendezvous
to be the mode of travel to the Moon, and they thought that would mean
two Saturn V-class launches per mission. So four of everything meant
two missions could be prepped simultaneously.

When Lunar Orbit Rendezvous was chosen instead, the fourth of
everything was defunded, with three of everything still going forward.
A year or two later, Pad 39C and the third Firing Room wer also
canceled, but we still got three High Bays in the VAB and three Mobile
Launchers.

perhaps a additional pad would of been built?


The logjam wasn't the launch pads, it was the Orbiter Processing
Facilites. KSC launched ten Shuttle flights in a one-year period (Jan
85-Jan 86) all from Pad 39A.

But neither additional OPFs or Pads would have solved the problem of
finding three major payloads ready to launch at the same time.

Brian
  #17  
Old February 15th 12, 05:57 PM posted to sci.space.history
Brian Thorn[_2_]
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Posts: 2,266
Default How many shuttle flights per year without Challenger accident?

On 2012-02-14 21:03:51 +0000, bob haller said:

NASA should of made enterprise flight worthy, at least as a automated
freight hauler.


Too expensive. Enterprise was never finished for spaceflight, and the
parts that it did have which were usable were pulled out and installed
in Challenger. Refurbishing Enterprise would have been no less
expensive than building a new Orbiter. And once you're talking that
kind of money, you have to start to question the best bang for the
buck. Shuttle-C or something like it would have been more useful for
about the same amount of money.

this would of brought lots of support for nasa and shuttles, remants
of this may have kept the program going even today. if enterprise
would of been flown automated the remaing orbiters could be too.

even with the columbia loss the program may have survived


Shuttle doesn't make sense without the humans onboard. If you just want
to launch an unmanned satellite, Atlas and Delta did the same job at
far, far lower cost. It is only because you are doing science
experiments, assembly or crew transfer that using Shuttle makes sense
(and even that is strongly disputed).

Brian

  #18  
Old February 16th 12, 04:58 AM posted to sci.space.history
Mike DiCenso
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Posts: 150
Default How many shuttle flights per year without Challenger accident?

On Feb 15, 9:57*am, Brian Thorn wrote:
Shuttle doesn't make sense without the humans onboard. If you just want
to launch an unmanned satellite, Atlas and Delta did the same job at
far, far lower cost. It is only because you are doing science
experiments, assembly or crew transfer that using Shuttle makes sense
(and even that is strongly disputed).


Not necessarily, having humans onboard an orbiter is all well in good,
but an automated orbiter can carry more cargo to and from space
without risking astronaut lives for "milk run" duty. I recall that
Rockwell estimated an automated orbiter could carry an additional
15.000 lbs (6,818 kg) without all the gear and crew supplies. And
that's the other thing you forgot is that STS' big advantage is being
able to return huge amounts of cargo from space, so a light-weight
automated orbiter hauling to space and back a fully filled MPLM is
priceless for ISS logistics. The big issue would be docking an
automated orbiter, but then Space Station Freedom plans often included
docking orbiters using the SSRMS, so that's not insurmountable.
-Mike
  #19  
Old February 16th 12, 05:55 AM posted to sci.space.history
Mike DiCenso
external usenet poster
 
Posts: 150
Default How many shuttle flights per year without Challenger accident?

On Feb 14, 4:50 pm, Brian Thorn wrote:
On 2012-02-14 19:06:13 +0000, Mike DiCenso said:



Agreed, though SLC-6 would have likely put a huge damper on things for
a while once the actual fueled testing of Columbia at that facility
revealed the flaws there.


I think that problem was trumped up by an Air Force that wanted out of
Shuttle at all costs. This would not have caused significant launch
delays.


True, but in an alternate reality where Challenger never happened,
that'd would have been much, much more difficult.


No. External Tank production would probably have peaked around 18 per
year. Michoud could handle a little more, but I doubt they would have
really pushed that hard. They'd have reduced the flight rate to keep
things under control.


They'd have had no choice, looking back on it. There were other
technical issues that would have forced delays or flight rate
reduction or caused a catastrophic loss.


I really don't think any of the other problems rose to the level of the
SRB field joint flaws, which had been showing signs of failure since
STS-2. The other issues, like the Quick Disconnect, were theoretical or
laboratory problems only, not actually seen in the real world. Fixes
could have been implemented over time, just as the SSME and brake
improvements were pre- and post-Challenger.

The biggest threat to flight rate was the cannibalization and spare
parts issue, but as I wrote, that could have been resolved during the
say, one year standdown while the field joint heaters are implemented,
pending the full capture-feature redesign to follow a year or two later.


All true, but if the O-ring issue had been taken more seriously and
flights delayed here and there to avoid inclement weather, the likely
scenario would be that other issues might have caused a catastrophic
failure that would've possibly killed a crew or at least caused some
really scary moments. And as we know now, with that kind of flight
rate, a Columbia-style accident could well have occurred in the early
1990s, rather than the early 2000s. Of course it's hard to say what
would happen since launch turnaround of a rescue orbiter would be far
faster than happened in Real Life because of the post-Challenger
induced changes, so such a thing might have had less effect on things.

So many variables.


If not that many, a dozen? 15?


Probably, if they funded a third OPF at KSC (without sacrificing SLC-6.)


Would the agency order a
fifth shuttle with such demand?


No, they would have backed out of the commercial market anyway,
relieving pressure on the 24-per-year goal. Arianespace would have
taken more commercial payloads regardless of Challenger.


Why? STS had huge cargo capacity for most of the then existing
satellite classes. Just load up a bunch of satellites into one mission
as was done for STS-41-D.


It was proving complicated to get all the payloads ready at the same
time. 41D itself was a an aberration caused by the cancellation of 41E
(or was it 41F?) leading to that flight being combined with 41D after
the RSLS abort in June. This is a continuing problem even today for
Ariane 5, which is why all indications are that Ariane 6 will be an
EELV-like one-at-a-time launcher. I suspect that even without
Challenger, Shuttle would have seen a major decline in commercial
payload launches, and NASA would not have complained all that much
about Ariane 4 taking that business. Congress would have complained
about the higher costs due to lower flight rate, but NASA would just
have said "Sorry, Arianespace is underbidding us" and quietly walked
away.


I doubt it. The trend was towards larger and larger individual
comsats, which would require fewer flights, but would most likely have
wound up taking up most or all of the payload bay, regardless if it
took up all the lift capacity. Although the Shuttle being more
successful than the Prime Timeline, could have resulted in more
satellites being built like the Leasat series. There also would have
been more LDEF missions, more EURECA, SPAS, SFUs, Spartan, satellite
repairs (especially Hubble), Spacelabs, Spacehabs, and of course
Freedom or ISS missions much different and earlier than occured in
Reality.
-Mike
 




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