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.

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.)

"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".

"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.

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 |

Henry Spencer wrote:
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.

If you'r recovering them significantly before halfway to orbit, then
it becomes a little easier.
Your stage may only be a few tens to a few hundred kilometers downrange, and
the velocity it's coming in at is only single digit Mach numbers.

You don't tend to need much thermal protection, and ensuring it always hits
ocean near your recovery vessel is probably easier.
Then again, the benefits are smaller.

Henry Spencer wrote:
HS The question is whether it is less trouble
HS to take them along, or to have them fall off
HS and be recovered separately. The answer is
HS not immediately obvious. Recovering stuff
HS that falls off halfway to orbit is not easy.

This is a very interesting topic, because it is
the essence of cheap access to space. Most rocket
launchers are disposable because they cannot
survive the reentry. The nose cone of the Space
Shuttle heats up to 1460 degrees Celsius during
reentry. 1460 degrees Celsius is about 1200
degrees above ambient temperature. How much would
the nose cone heat up if the reentry velocity
was reduced by half? My guess is that the nose
cone temperature would be 1/4 of 1200 degrees
above ambient temperature, or about 300 degrees
Celsius. That is not bad! I believe that structural
stress is much bigger problem for the flimsy tanks
of the pump-fed rockets. This is another argument
in favor of the sturdy, pressure-fed rockets.

__________________________________________________ ____


Ian Stirling wrote:
IS If you'r recovering them significantly before
IS halfway to orbit, then it becomes a little easier.
IS Your stage may only be a few tens to a few
IS hundred kilometers downrange, and the velocity
IS it's coming in at is only single digit Mach numbers.

But then your launcher has three stages instead of
two

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.

Andrew Nowicki wrote in message ...
Alan Anderson wrote:
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...

Look at:

http://media.armadilloaerospace.com/...BoostedHop.mpg

An actual pressure fed rocket with almost no moving parts doing a
powered landing. It is my considered opinion that this is The Right
Way To Do It. Build a big, simple booster that lofts a high
performance upper stage all the way out of the atmosphere, then
returns to land on the same pad it took off from. At first flance it
sounds like an inefficient staging strategy, since the upper stage
requires nearly SSTO dV, but removing the requirment of boosting
through the atmosphere (optimize only for vaccuum boost and reentry)
does still simplify the problem quite a bit, and the operational and
testing aspects are great.

John Carmack
www.armadilloaerospace.com

"John Carmack" wrote in message
om...
Andrew Nowicki wrote in message
...
Alan Anderson wrote:
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...

Look at:

http://media.armadilloaerospace.com/...BoostedHop.mpg

An actual pressure fed rocket with almost no moving parts doing a
powered landing. It is my considered opinion that this is The Right
Way To Do It. Build a big, simple booster that lofts a high
performance upper stage all the way out of the atmosphere, then
returns to land on the same pad it took off from. At first flance it
sounds like an inefficient staging strategy, since the upper stage
requires nearly SSTO dV, but removing the requirment of boosting
through the atmosphere (optimize only for vaccuum boost and reentry)
does still simplify the problem quite a bit, and the operational and
testing aspects are great.

John Carmack
www.armadilloaerospace.com

I may be in disagreement with you about the nearly SSTO performance
requirement. MR for SSTO seems to be about 16 (Lox/Kero) from the
ground, and 10 from the vacuum altitude you deliver to. Going from
6.25% dry mass including payload to 10% dry mass including payload
is a major gain in margins. Even without the mass savings on lighter
engine and tank mass percentage, 37.5% of the upper stage dry mass
becomes available to increase payload. I was convinced several years
ago by Len Cormiers' Space Van booster concepts.

I think our goals might be similar with a slight difference in methods and
means :-), not to mention real world experience. I hope to start closing the
gap on the last two real soon now, same as I did last year, and the year
before that....