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  #41  
Old December 18th 07, 06:51 PM posted to sci.space.policy
Len[_2_]
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On Dec 18, 12:03 am, Fred J. McCall wrote:
Len wrote:

:
:Another factor was the SSME, which used a lot of
:material rejected for the RL10 because of hydrogen
:embrittlement--not to mention a spindly shaft going
:through several stages of instability getting up to speed,
lus pressure gradients running from hot to cold, rather
:than vice versa. This was not a good starting design
:for a reusable engine.
:
:I remember being chastised by some NASA folks
:for calling the RL10 reusable, based upon hard test
:data. No. The RL10 by definition was expendable;
:the SSME by definition was reusable.
:
:Just invoking the word reusability does not ensure
:low-costs.
:

Exactly. Running hardware at 100% of design (or beyond) as routine
operation almost guarantees that a reusable vehicle will be quite
expensive (because of teardown, overhaul, and inspection costs).


We plan to derate the first-stage engines
to 80 percent for an order-of-magnitude
improvement in engine maintenance costs.
Even with de-rating, we can still fly on one
of the two rocket engines at critical takeoff
speed. The two DK-30 landing engines in
the carrier are sized for landing; thrust from
this source is incidental at takeoff.

At the moment, I am assuming about
90 percent derating for the orbiter LOx/kero
engine. One version of the orbiter has
additional RL10A-4 engines to allow limiting
acceleration to 3 gs and to pick up signifcantly
more payload; these look quite
reusable at 100 percent.

Len

--
"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


  #42  
Old December 18th 07, 06:55 PM posted to sci.space.policy
Len[_2_]
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On Dec 17, 5:02 pm, Fred J. McCall wrote:
Ian Parker wrote:

:
:If you are
:a tourist you are risking your life for no really good purpose.
:

And yet this doesn't stop people from engaging in mountain climbing,
etc.


In a perverse way, it may be part of the
attraction.

IMO, part of the joy of being a fighter
pilot is the addiction to adrenalin rushes.

Len

--
"Rule Number One for Slayers - Don't die."
-- Buffy, the Vampire Slayer


  #43  
Old December 18th 07, 07:55 PM posted to sci.space.policy
Eric Chomko[_2_]
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On Dec 17, 4:47 pm, Ian Parker wrote:
On 17 Dec, 19:55, Eric Chomko wrote:



On Dec 16, 4:04 pm, Fred J. McCall wrote:


Ian Parker wrote:


:
:Basically the viability of SPS depends on transportation.
:


It depends on much more than that. It depends on all sorts of
resource costs, development costs, etc.


:
:If you are saying that it will be enormously easier with asteroid
:material, you are of course right. What I was trying to work out was
:the establishment of a market of some description.
:


You can't work out the establishment of a market until you can talk
about costs and prices.


:
:I do not believe there will be enough tourists for a killer market.
:"Killer" here refers to the market that justifies the costs and drives
:it.
:


I don't believe we'll get to space at all if we're waiting for the
proverbial 'killer app'. Think 'small bites'.


The term "Killer App" (which I think is beyond silly), conjurs up
thoughts of the Hindenburg disaster when applying it to manned
commercial spaceflight.


Rand used the Grand Canyon as an analogy. I bet he has not read the
very popular book, "Death in the Grand Canyon". It basically speaks
about the fact that many people die in the GC due to not using common
sense.


Eric- Hide quoted text -


Just one quick point of information "Killer app" was coined in
computer science for the application that would pay for a new
generation of computers, operating system etc. Perhaps though you are
right, it is a silly term.


I am a computer professional and well aware of where the term "killer
app" comes from. Gates started using it and it took off from there.


The question of risk in space travel is not however a trivial point.
We were also told the Shuttle would be "safe". It wasn't. I think
there may well be a moral question here. If you are a professional
astronaut you take risks, you have to to get the job done. If you are
a tourist you are risking your life for no really good purpose.


No doubt commercial spaceflight related to tourists in space will have
accidents. It is inevitable.

My experience of tourism and risk is of going round an empty Krak (and
other places like Ugarit and Palmyra). It was nice. I could just trail
behind everyone else and get clear shots with my camera.. There the
risk was very low - only the CIA claims there was any at all. Krak des
Chevaliers is every bit as magnificent in its way as the grand canyon.
But people don't go there.

I am inclined to feel thast when this question of risk comes up people
will back off. I am not sure in my own mind how much tourism is to be
encouraged. OK in a free society you cannot stop people, but this
consideration is always at the back of my mind.


No one expects to get hurt in a man-made fortress, though Syria is not
a friendly country. I can't help thinking about the group of Greek
tourists killed in Egypt about a decade ago. However, people get the
wrong idea about the wilderness. No one expects people to kill other
people in a national park. On the same token a NP isn't Disneyland
either where someone is always present to rescue people in trouble.
The rangers at NPS do as best they can but they can't guarantee safety
especially where someone doesn't use common sense. Don't climb past a
barrier for a better view. I mean the damn fence or barrier is there
for a reason but sure enough every few years some fool simply must
have a better view and bamm, over the edge... Also, a 4 year old girl
fell over the edge, just this past October, due to her parents paying
more attention to the canyon than their daughter.

Space tourism will have its own set of challenges with saftey. Some
idiot is simply bound to see if he can survive in a vacuum with no
equipment, that is one you can count on.
  #44  
Old December 18th 07, 08:02 PM posted to sci.space.policy
Eric Chomko[_2_]
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Posts: 2,853
Default Cheap Access to Space

On Dec 18, 12:03 am, Fred J. McCall wrote:
Len wrote:

:
:Another factor was the SSME, which used a lot of
:material rejected for the RL10 because of hydrogen
:embrittlement--not to mention a spindly shaft going
:through several stages of instability getting up to speed,
lus pressure gradients running from hot to cold, rather
:than vice versa. This was not a good starting design
:for a reusable engine.
:
:I remember being chastised by some NASA folks
:for calling the RL10 reusable, based upon hard test
:data. No. The RL10 by definition was expendable;
:the SSME by definition was reusable.
:
:Just invoking the word reusability does not ensure
:low-costs.
:

Exactly. Running hardware at 100% of design (or beyond) as routine
operation almost guarantees that a reusable vehicle will be quite
expensive (because of teardown, overhaul, and inspection costs).


Wow! Fred actually agreed with someone. Usually he'd ignore a post
like that and only answer one where he can blast the poster. I
consider this progress on Freddy's part. Maybe he got laid recently?

Eric


  #45  
Old December 18th 07, 08:37 PM posted to sci.space.policy
Ian Parker
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Posts: 2,554
Default Cheap Access to Space

On 18 Dec, 18:55, Eric Chomko wrote:

Space tourism will have its own set of challenges with saftey. Some
idiot is simply bound to see if he can survive in a vacuum with no
equipment, that is one you can count on.- Hide quoted text -

I wasn't talking about deliberate stupidity, I was thinking about the
basic unreliability of launchers and reentry + the radiation received.
Solar flres etc.

We were told the Shuttle was going to be safe and cheap. It was
neither.


- Ian Parker

  #46  
Old December 18th 07, 08:45 PM posted to sci.space.policy
Ian Parker
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Posts: 2,554
Default Cheap Access to Space

On 18 Dec, 16:21, BradGuth wrote:
At less than a tenth the NASA cost per LEO or GSO kg, China is CATS.

Of course China is going to charge outsiders a whole lot more than
whatever it's costing themselves.
- Brad Guth

I have stated that the key to low cost is consolidation &
globalization. There is one ingredient that is required for this and
that is transparancy. China may well be adopting the Ford Focus route
and this may well be the basis for costings.

However we do not have transparent figures for the Long March. You
might say the Long March to transparency. They do have a motive for
selling at below cost. Prestige + a possible loss leader.


- Ian Parker
  #47  
Old December 18th 07, 11:48 PM posted to sci.space.policy
BradGuth
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On Dec 18, 11:45 am, Ian Parker wrote:
On 18 Dec, 16:21, BradGuth wrote: At less than a tenth the NASA cost per LEO or GSO kg, China is CATS.

Of course China is going to charge outsiders a whole lot more than
whatever it's costing themselves.
- Brad Guth


I have stated that the key to low cost is consolidation &
globalization. There is one ingredient that is required for this and
that is transparancy. China may well be adopting the Ford Focus route
and this may well be the basis for costings.

However we do not have transparent figures for the Long March. You
might say the Long March to transparency. They do have a motive for
selling at below cost. Prestige + a possible loss leader.

- Ian Parker


Their more than qualified expertise in such physics and now more than
proven as reliable fly-by-rocket technology doesn't or at least
shouldn't require a "lost leader", especially when just about every
other nation on Earth is begging for the best and least cost
alternatives of getting the most of whatever payload deployed while
using the best failsafe of methods in exchange for each of their hard
earned loot. Unless artificially created by the likes of us, there's
no ulterior or even perpetrated cold-war motives for China to fail at
delivering the most rocket deployed bang for our badly energy inflated
buck, perhaps a good enough deal for us even if they charged ten fold
whatever it's costing for the same as having deployed one of their
own.
- Brad Guth
  #48  
Old December 19th 07, 03:41 AM posted to sci.space.policy
Alain Fournier[_2_]
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John Schilling wrote:

If a rocket crashes, it will probably "explode". Big-ass fireball, at
very least. But the same tends to be true of jet airplanes, and in
either case the explosion is almost always A: the result, not the cause,
of the crash, and B: irrelevant because the vehicle and payload were
already lost on account of being smashed into the ground at high speed
or something like that.


The rest of your post is all true, but the fire after an airplane crash
is not at all irrelevant. The vast majority of passengers in airplane
crashes survive the crash, many of them do not survive the fire. For
rocket rides the odds are very different.


Alain Fournier
  #49  
Old December 19th 07, 11:49 AM posted to sci.space.policy
Ian Parker
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Posts: 2,554
Default Cheap Access to Space

On 18 Dec, 22:48, BradGuth wrote:
On Dec 18, 11:45 am, Ian Parker wrote:





On 18 Dec, 16:21, BradGuth wrote: At less than a tenth the NASA cost per LEO or GSO kg, China is CATS.


Of course China is going to charge outsiders a whole lot more than
whatever it's costing themselves.
- Brad Guth


I have stated that the key to low cost is consolidation &
globalization. There is one ingredient that is required for this and
that is transparancy. China may well be adopting the Ford Focus route
and this may well be the basis for costings.


However we do not have transparent figures for the Long March. You
might say the Long March to transparency. They do have a motive for
selling at below cost. Prestige + a possible loss leader.


- Ian Parker


Their more than qualified expertise in such physics and now more than
proven as reliable fly-by-rocket technology doesn't or at least
shouldn't require a "lost leader", especially when just about every
other nation on Earth is begging for the best and least cost
alternatives of getting the most of whatever payload deployed while
using the best failsafe of methods in exchange for each of their hard
earned loot. Unless artificially created by the likes of us, there's
no ulterior or even perpetrated cold-war motives for China to fail at
delivering the most rocket deployed bang for our badly energy inflated
buck, perhaps a good enough deal for us even if they charged ten fold
whatever it's costing for the same as having deployed one of their
own.
- Brad Guth- Hide quoted text -

- Show quoted text -


I don't know whether this is true of false but any claim needs
extensive verification. As you know the role for NASA which I
postulate is primerally that of a regulator. NASA has to examine Long
March in terms of WTO rules. There are complications as I have
mentioned but it can be done.

Fundamentally going into space with a "Ford Focus" is legal. Dumping,
or selling below cost, is illegal.


- Ian Parker
  #50  
Old December 19th 07, 12:40 PM posted to sci.space.policy
Ian Parker
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Posts: 2,554
Default Cheap Access to Space

http://afp.google.com/article/ALeqM5...okP1pt8lCtBfxw

This is an article on the Chinese challenge in general terms. I think
a lot of people are far too complacent.


- Ian Parker
 




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