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Mojave airport is not a spaceport



 
 
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  #1  
Old June 19th 04, 10:10 PM
Andrew Nowicki
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Default Mojave airport is not a spaceport

The Mojave Airport is a perfect place to test
airplanes and sounding rockets, but it is probably
the worst place on Earth to locate the space rocket
launch site -- Manhattan would be better. There is
no ocean to the east of Mojave, so you cannot make
cheap pressure-fed rockets, splash them down and
reuse them. A big city (Los Angeles) is just 100 km
south of Mojave. The nearest pacific coast is 130 km
south west, next to Ventura, California. If you
launch the real thing, you will have to launch it
in the south west direction and hope it will not
fall on Los Angeles.

NASA should make the Kennedy Space Center available
to independent rocket makers.
  #2  
Old June 19th 04, 11:07 PM
Henry Spencer
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Default Mojave airport is not a spaceport

In article ,
Andrew Nowicki wrote:
The Mojave Airport is a perfect place to test
airplanes and sounding rockets, but it is probably
the worst place on Earth to locate the space rocket
launch site -- Manhattan would be better.


Hardly. Mojave *is* out in the middle of nowhere, which is why a lot of
aircraft testing already gets done there. The biggest hazards from
rocketry are in the immediate vicinity of the launch site.

There is no ocean to the east of Mojave, so you cannot make
cheap pressure-fed rockets, splash them down and
reuse them.


You couldn't do that from Mojave Spaceport anyway, because (last I heard)
their spaceport license is for horizontal-takeoff-horizontal-landing
launch vehicles only. They've decided to cater to one particular type of
vehicle, rather than covering the whole spectrum.

If you're going to build vehicles resembling artillery rockets, where
pieces deliberately fall off during ascent and make uncontrolled landings,
then quite likely you are going to have to launch over water. That's not
the only design option.

A big city (Los Angeles) is just 100 km south of Mojave.


Orlando is about the same distance from the Cape, and Vandenberg is not
much farther away from L.A.

If you launch the real thing, you will have to launch it
in the south west direction and hope it will not fall on Los Angeles.


No, you launch eastward, and establish sufficiently low probability of
casualties by good design and proper testing. (Operating only over
largely uninhabited areas certainly *helps* -- it means you can achieve
the required level of safety even with a relatively high estimated
probability of failure, which is easier to justify -- but it is not
actually required.)

Note that there is no launch site on Earth where your debris footprint
will be on water throughout ascent. Even launching from the Cape, some
possibility of hitting Africa must be accepted.

NASA should make the Kennedy Space Center available
to independent rocket makers.


The Cape is already available to commercial rocket builders, and has been
for quite a while. The bureaucratic hurdles are considerable -- and they
would not get easier at KSC, because the USAF is in charge of range safety
either way -- and the overhead costs are high, but it is available.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |
  #3  
Old June 19th 04, 11:16 PM
Alan Anderson
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Default Mojave airport is not a spaceport

Andrew Nowicki wrote:

There is
no ocean to the east of Mojave, so you cannot make
cheap pressure-fed rockets, splash them down and
reuse them.


If you're going to reuse them in any significant fashion, "cheap" is a
loaded term. You want them to be economical to use, certainly, but that's
not the same thing as being inexpensive to build (or buy) in the first
place.

I've always agreed with the idea that dropping machinery in sal****er and
fishing it back out isn't a great thing to do if you want to use it again
without significant refurbishing. What's wrong with spending the bit of
extra effort required to simply *land* the things and reuse them?
Appropriate up-front engineering can lower the operational costs of
staging. A lot of cost can be saved if your first stage rocket comes back
to the launch site by itself, and if it basically just needs to be brushed
off and recharged/refueled before it's ready to have an upper stage
vehicle latched on for the next launch.

(For that matter, what's wrong with spending the next bit of extra effort
required to make "first-stage rockets" as quaint as capsule splashdowns?
The ultimate reduction in the operational costs of staging is to remove
staging completely.)
  #4  
Old June 19th 04, 11:52 PM
Perplexed in Peoria
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Default Mojave airport is not a spaceport


"Alan Anderson" wrote in message
...
(For that matter, what's wrong with spending the next bit of extra effort
required to make "first-stage rockets" as quaint as capsule splashdowns?
The ultimate reduction in the operational costs of staging is to remove
staging completely.)


To eliminate staging, you need to provide:
1. Enough extra wing to land the big "first stage" tanks.
2. Enough extra shielding to re-enter tanks and wing.
3. Enough extra fuel to deorbit tanks, wings, and shielding.
4. Enough extra fuel to get tanks, wings, shielding, and
extra fuel into orbit in the first place.
5. A larger "first stage" tank to hold the extra fuel for
requirements 1-4.
6. And so it cycles.

These requirements don't go away with a "bit of extra effort"
at the design and manufacturing stage. Maybe eliminating
staging saves enough operationally to make sense. But maybe
we should be trying to cut those operational costs without
resorting to fundamentally wasteful expenditure of resources
lifting and returning things that we don't use while we are
"up there".


  #5  
Old June 20th 04, 12:37 AM
Andrew Nowicki
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Default Mojave airport is not a spaceport

Alan Anderson wrote:

I've always agreed with the idea that dropping machinery
in sal****er and fishing it back out isn't a great thing
to do if you want to use it again without significant
refurbishing.


What is wrong with it? You can keep an unpainted titanium
rocket in the sal****er for many years without any adverse
effects except biofouling (things growing on it). There are
paints which prevent biofouling. Unpainted aluminum rocket
can be kept in the salt water for a few days without any
signs of corrosion. (Many large ships and tankers are made
of painted aluminum. The Coast Guard is replacing its steel
buoys with aluminum buoys.)

What's wrong with spending the bit of extra effort required
to simply *land* the things and reuse them?


The pressure-fed rocket has almost no moving part. It can
be made in a shipyard. The rocket-plane is at least one
order of magnitude more expensive. It has lots of moving
parts which can fail. Look at the russian Baikal:
http://www.spacedaily.com/news/rocketscience-03j.html
It has foldable wings, jet engines, landing gear...

Appropriate up-front engineering can lower the operational
costs of staging. A lot of cost can be saved if your first
stage rocket comes back to the launch site by itself, and
if it basically just needs to be brushed off and
recharged/refueled before it's ready to have an upper stage
vehicle latched on for the next launch.


If the rocket-planes do not crash upon landing, they may be
feasible. Anyway, the idea of a reusable first stage is more
important than its implementation. The range safety is more
important -- I doubt anyone can get a permit to fly his rocket
launcher over a populated area.
  #6  
Old June 20th 04, 03:10 AM
Andrew Nowicki
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Default Mojave airport is not a spaceport

Andrew Nowicki wrote:

AN There is no ocean to the east of Mojave,
AN so you cannot make cheap pressure-fed rockets,
AN splash them down and reuse them.

Henry Spencer wrote:

HS You couldn't do that from Mojave Spaceport anyway,
HS because (last I heard) their spaceport license is
HS for horizontal-takeoff-horizontal-landing launch
HS vehicles only. They've decided to cater to one
HS particular type of vehicle, rather than covering
HS the whole spectrum... you launch eastward...

Single stage rocket launchers do not exist. Does it
mean that the spent first stage is dropped near
Phoenix, Arizona, and the spent second stage is
dropped on Texas?
  #7  
Old June 20th 04, 03:59 AM
Henry Spencer
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Default Mojave airport is not a spaceport

In article ,
Andrew Nowicki wrote:
HS You couldn't do that from Mojave Spaceport anyway,
HS because (last I heard) their spaceport license is
HS for horizontal-takeoff-horizontal-landing launch
HS vehicles only...

Single stage rocket launchers do not exist.


Neither do the pressure-fed launchers you're talking about.

Does it mean that the spent first stage is dropped near
Phoenix, Arizona...


No, its pilot turns it around and flies it back to base. Or, possibly,
glides it down to a landing at some suitable airstrip, from which it is
trucked or flown back to Mojave, although that's rather less convenient.
What part of "horizontal-takeoff-horizontal-landing only" is so hard for
you to grasp?

Your pressure-fed artillery rockets will *never* operate out of Mojave,
and it's got nothing to do with where the pieces falling off would land.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |
  #8  
Old June 20th 04, 04:01 AM
Henry Spencer
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Default Mojave airport is not a spaceport

In article om,
Perplexed in Peoria wrote:
...Maybe eliminating
staging saves enough operationally to make sense. But maybe
we should be trying to cut those operational costs without
resorting to fundamentally wasteful expenditure of resources
lifting and returning things that we don't use while we are
"up there".


The question is whether it is less trouble to take them along, or to have
them fall off and be recovered separately. The answer is not immediately
obvious. Recovering stuff that falls off halfway to orbit is not easy.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |
  #9  
Old June 20th 04, 04:09 AM
Christopher M. Jones
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Default Mojave airport is not a spaceport

Andrew Nowicki wrote:
Single stage rocket launchers do not exist. Does it
mean that the spent first stage is dropped near
Phoenix, Arizona, and the spent second stage is
dropped on Texas?


Actually, single stage rocket launchers do exist.
As do rockets with entirely reusible stages
throughout. Single stage *orbital* launchers do
not, but nobody's flying those out of Mojave any
time soon so that's a non-issue.
  #10  
Old June 20th 04, 06:02 AM
Alan Anderson
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Default Mojave airport is not a spaceport

"Perplexed in Peoria" wrote:

To eliminate staging, you need to provide:
1. Enough extra wing to land the big "first stage" tanks.


Wet wings can help here. But who says you need wings in the first place?

2. Enough extra shielding to re-enter tanks and wing.


You're talking thermal protection, right? If the vehicle is big and light
at reentry, dealing with the heating problem should be *easier*.

3. Enough extra fuel to deorbit tanks, wings, and shielding.
4. Enough extra fuel to get tanks, wings, shielding, and
extra fuel into orbit in the first place.
5. A larger "first stage" tank to hold the extra fuel for
requirements 1-4.


Fuel is cheap.

6. And so it cycles.


If you start with something large enough to meet the requirements in the
first place, you don't have to iterate making it larger.

These requirements don't go away with a "bit of extra effort"
at the design and manufacturing stage. Maybe eliminating
staging saves enough operationally to make sense. But maybe
we should be trying to cut those operational costs without
resorting to fundamentally wasteful expenditure of resources
lifting and returning things that we don't use while we are
"up there".


Those "resources" are essentially propellant. Wasting something that
isn't all that expensive is not a large problem.
 




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