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  #11  
Old January 15th 12, 02:11 AM
SarK0Y SarK0Y is offline
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Jorge, what you're talking about has been only the matter of law. this situation can & must be changed, if govt did or does desire to've had real Space Industry instead of Just amazing pics from nasa.gov! :-)

hmmmm, Dave, strategies from private companies look badly weird, softly to say. let's take vg 4 example: suborbital flights are completely possible even with not very intensive funding (conventional, not even medium-class, rocket + capsule makes cost the lesser than 500k per seater), but they've put far more hard scheme in basis. in short, most poor safety + price to be going wild. only lazy one doesn't say "reusable rockets kick prices awfully down". :-) C'mon, my friends! reusable ones cannot be cheaper at the current techs: re-usability makes'em be heavy-class (greater expenses 4 service works, more complicated infrastructure/logistics, big chance to fail safety standards). they, all,'ve done everything good to share the fate of solyndra. suborbital flights with lottery scheme are only way start from + 1st steps must take in place only maximally proven solutions! 2nd phase will reduce costs to put payload to the Earth orbits.
-----------
Amici(Friends), to put Space Industry onto own feet is damned hardest challenge & right way must be taken as soon as possible, otherwise Energy/Water/Food shortage, Natural & man-made Disasters shall be only future.
  #12  
Old January 16th 12, 02:18 AM posted to sci.space.policy
David Spain
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SarK0Y wrote:
hmmmm, *Dave*, strategies from private companies look badly weird,


Well to take your point (I think), that expendable hardware is cheaper than
reusable hardware. As has been discussed here many times before that all depends.

One of the things it depends upon is flight rate. The more frequent the
flights the more a reusable system will cut costs, since you're not replacing
the vehicle each time. In fact the ideal system would only require refueling
and minimal servicing between flights.

The other factor you mention is safety. As Jeff has pointed out here many
times, safety is somewhat easier to enhance on reusable vehicles where you can
modify and measure the result of the enhancement. You can do this with
expendables, but it requires retooling for the production line each time you
introduce a change, if you want that change to be available in successor vehicles.

The $500k / seat figure you mention has already been overcome by VG. They are
offering initial seats at $200k / seat, with the cost expected to come down as
the flight rate increases, which has yet to be seen, I admit. However I think
it more likely for the price to come down with reusable hardware than otherwise.

My two cents.

Dave
  #13  
Old January 16th 12, 04:05 AM
SarK0Y SarK0Y is offline
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Dave, re-usability could be rational only with more compact & powerful energy sources than conventional fuel. Just compare how weighty expendable & reusable rockets should be to lift 20 tonnes payload off. give me some examples, please, where re-usability really makes cost down.
  #14  
Old January 16th 12, 08:23 AM posted to sci.space.policy
David Spain
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Fred J. McCall wrote:
David Spain wrote:

One of the things it depends upon is flight rate. The more frequent the
flights the more a reusable system will cut costs, since you're not replacing
the vehicle each time. In fact the ideal system would only require refueling
and minimal servicing between flights.


It's not just flight rates, but processing between flights that drives
reusable cost vs expendable cost. If your 'reusable' launcher is
actually 'rebuildable' (standing army to do refurbishment and
inspection of, well, pretty much everything) it is going to cost more.
If, on the other hand, the required servicing can be held down, the
reusable will be a big win.

Shuttle *COULD* have been designed that way (and it's necessary to
design that stuff in), but chose to be otherwise for initial cost
reasons. It was a bad decision...


No argument from me.

However my take is just a little different. My biggest beef with shuttle was
that it couldn't evolve or rather wasn't allowed to. If a mfg. pipeline could
have been maintained that popped out a new orbiter every 5 years or so,
experience gained handling the older models could have been used to cost
reduce operations of the new models. Savings to be recouped as the older
models are retired. Instead we tried to build out a fleet all at once, I guess
presuming to save money up front, triple tasking between commercial ops (which
never really panned out, NASA is a pretty pricey vendor and Challenger pretty
much put the kabosh on that idea), space exploitation (read space station) and
military payloads (see issue(s) with commercial ops). And once the last
orbiter was built that was it.

That's one of the aspects of COTS/CCDev that I like the best. That it allows
the mfg. to be free to continue to develop and refine its vehicles. The idea
being the mfg. is free to do this because it can offer its hardware
commercially to paying customers other than NASA. SpaceX is trying hard with
its booster hardware to do this. With Dragon it seems less apparent to me that
will be the case, mainly because the only destination for it today is the ISS.
If Bigelow ever literally gets off the ground that could be a game changer. So
we'll see.

I'm not going to muddy the waters talking about the Congressionally mandated
SLS rocket to nowhere welfare program and its retro approach to everything.
We all know how well under-funded federal mandates work out.

Dave

  #15  
Old January 16th 12, 04:54 PM posted to sci.space.policy
David Spain
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Fred J. McCall wrote:
The problem with this approach on reusable vehicles is that you wind
up with a fleet of 'one offs', each of which has its own special
reprocessing requirements and logistics tail. That's a very expensive
way to operate.


But you do still have the re-usability that you lose with expendables.
But I agree with your point that the operational cost is a question of ground
infrastructure. My point was that this is the goal of the cost reduction, if I
can retire the costly to operate vehicles quickly maybe I can get the ground
infrastructure cost down as well. And I'd only be servicing a smaller number
of vehicles (say two, with a CRV on standby with an expendable) rather than an
entire fleet of four or five, however with a new vehicle coming on line every
5 years or so. I think having only say two operational orbiters at any given
time + CRV as a backup (given the sustainable flight rates NASA was able to
achieve) would have been just fine. But your point is well taken. With the one
size fits all Shuttle approach that was taken, and the lower flight rates
post-Challenger, this still might have been too costly to do.

What really needs to happen (and this requires a huge expansion in
launch rates) is to build 'blocks' of vehicles. But that requires
being able to upgrade the older 'blocks' to newer to avoid what is
only a slightly less onerous cost model than doing this on a single
vehicle basis.


Check. Yes that is the military model and it works pretty well.
Look at the life of the B52 as an example.

The 'constant upgrade' path works better for expendables or for
reusables that are only good for a very small number of reuses.


Well no I disagree. We see it with military hardware all the time
(see your argument above), but since that is an aviation model not a space
model maybe the analogy doesn't extend.

Perhaps the real problem is we just really haven't gotten to the numbers of
reuses (read flights) out of space hardware that would make the difference?

Dave

  #16  
Old January 16th 12, 05:10 PM posted to sci.space.policy
David Spain
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SarK0Y wrote:
*Dave*, re-usability could be rational only with more compact & powerful
energy sources than conventional fuel.


? What does the X37-B use? Cavorite?

Just compare how weighty
expendable & reusable rockets should be to lift 20 tonnes payload off.
give me some examples, please, where re-usability really makes cost
down.


20 tonnes? I thought we were talking about vacation jaunts to sub-orbital
frolics? I'm pretty sure SpaceShip Two doesn't come in at that. In fact I'm
fairly sure that SS-II and WK-II combined don't come in at that. But I can check.

If you want an example that is on-topic to your OP, compare operational costs
of VG to that other Canadian competitor that was going to do this with a
rocket, what was there name? Canadian Arrow I think. Even that rocket was to
be reusable IIRC. The Canadian Arrow team was a serious and close competitor
to Scaled Composites for the Ansari X-Prize, but lost and has since bowed out
of attempting commercial sub-orbital jaunts. And that was with an all rocket
tech, not an aircraft/spacecraft hybrid.

Dave
  #17  
Old January 16th 12, 08:03 PM posted to sci.space.policy
Mike DiCenso
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On Jan 16, 7:36*am, Fred J. McCall wrote:
David Spain wrote:

However my take is just a little different. My biggest beef with shuttle was
that it couldn't evolve or rather wasn't allowed to. If a mfg. pipeline could
have been maintained that popped out a new orbiter every 5 years or so,
experience gained handling the older models could have been used to cost
reduce operations of the new models. Savings to be recouped as the older
models are retired. Instead we tried to build out a fleet all at once, I guess
presuming to save money up front, ...


The problem with this approach on reusable vehicles is that you wind
up with a fleet of 'one offs', each of which has its own special
reprocessing requirements and logistics tail. *That's a very expensive
way to operate.

What really needs to happen (and this requires a huge expansion in
launch rates) is to build 'blocks' of vehicles. *But that requires
being able to upgrade the older 'blocks' to newer to avoid what is
only a slightly less onerous cost model than doing this on a single
vehicle basis.


That was possible, Rockwell (back before Boeing took over) offered to
build NASA three new orbiters for the price of Endeavour by
piggybacking their construction on the line. NASA refused, apparently
citing your reasoning above since these new orbiters would have had
upgrades built into them that were far more substantial than anything
previously possible.

As for the "one off" issue. We did see that. That's what Enterprise,
Columbia and Challenger were. Each one of them had very signifcant
deviations from the more standardized Discovery, Atlantis and
Endeavour.

The 'constant upgrade' path works better for expendables or for
reusables that are only good for a very small number of reuses.


Except that people forget all too easily just how much in the way of
significant upgrades were made to the orbiters and to the STS system
as a whole. The Block I-III series of SSME upgrades that were a major
improvement in safety, reliability, and maintenance over the phase-II
engines, for instance. Or the MEDS glass cockpit upgrades. The
replacement of the ET with increasingly lighter weight ones and so on.
What would be done if NASA had excepted Rockwell's offer would have
been to take the older orbiters out of service for several for a very
extensive rebuild at Palmdale after the Block II orbiters came into
service. Sadly there probably would not have been any money for such
an effort.
-Mike
  #18  
Old January 16th 12, 09:24 PM posted to sci.space.policy
Glen Overby[_1_]
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Mike DiCenso wrote:
What would be done if NASA had excepted Rockwell's offer would have
been to take the older orbiters out of service for several for a very
extensive rebuild at Palmdale after the Block II orbiters came into
service. Sadly there probably would not have been any money for such
an effort.


Why rebuild all of them? They only ever had four flying orbiters at a time so
they could have flow three Block II orbiters and one older one, using the
remaining Block I orbiters as spares for it.

- glen
  #19  
Old January 17th 12, 02:11 AM
SarK0Y SarK0Y is offline
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Dave, i dont've anything against reusable spacecraft per se, but let's get real: No one has shown cheap, reliable solutions 4 manned missions. chemical rockets struck'ir ceiling, vg even cannot provide suborbital flights, space x has risen their prices & reliability of the musk's torpedoes is question yet. reusable spaceships are hella possible, but not onto chemical "food" ;-) needs to develop new power systems & methods to transmit energy, then expendable will become only great history. these R&D's shall take some Time + some cents XD i said how to mine'em -- if 1st phase will get in reality, we can discuss next one.
  #20  
Old January 17th 12, 02:34 PM posted to sci.space.policy
David Spain
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Default Public letter:

SarK0Y wrote:
*Dave*, i dont've anything against reusable spacecraft per se, but let's
get real: No one has shown cheap, reliable solutions 4 *manned*
missions. chemical rockets struck'ir ceiling, vg even cannot provide
suborbital flights, space x has risen their prices & reliability of the


I think VG is getting very, very close. I haven't been following their
progress but perhaps by end of this year or next this statement may no longer
be true?

musk's torpedoes is question yet.


Musk claims to have booked considerable amount of business for Falcon 9
already with or w/o NASA COTS. Time will tell, not much time mind you.

reusable spaceships are hella
possible, but not onto chemical "food" ;-)


You need to provide evidence of this. I don't see any. Musk's plan is to make
Dragon re-usable at the outset. And the next gen of Dragon is to land on land
to speed refurbishment.

needs to develop new power
systems & methods to transmit energy, then -expendable- will become only
great history. these R&D's shall take some Time + some cents XD i said
how to mine'em -- if 1st phase will get in reality, we can discuss next
one.


In the immediate future I think there will be a healthy mix of re-usable and
expendable. For heavy cargo going 1-way, expendable HLLs would still seem the
cheapest way to go.

But if Stratolaunch gets going seriously, then there'll be a healthy
competitor there to expendables for lighter cargo transport and possibly HSF.

Dave
 




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