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Leopold Stotch wrote:
kT wrote

The foam problems still remain as the fundamental engineering science
of rocket science, something America has abandoned with Michael Griffin.


The "foam problem" is only a problem when you mount the crew vehicle in
tandem with the booster the way the STS does. Put the crew vehicle on
the top and shed foam till the cows come home, who cares? So long as
there is nothing important to hit foam shedding is not an issue. Hell,
put the CV on top and forget about putting foam on the thing at all.

Actually, the foam problem is a universal orbital debris problem for all
upper stages and core stages that remain in orbit, or that are intended
to remain in orbit. For instance, you lose 60% - 75% of your payload
mass if you expend upper stages or in orbit, or in the case of core
stages, expend them after attaining 97% or more of orbital velocity.

The foam degrades in ultraviolet and creates a huge mess on orbit. If
you want to recycle those upper stages or core stages on orbit, the foam
problem must be solved. It's the number one problem of rocket science.

Of course, if you want to waste 60% to 75% of your payload, that's your
choice. Maybe it makes you so proud to be wasteful, and proud to neglect
the problems of rocket science as you have done these last eight years.
If you are an American, considering the state of America, it doesn't
surprise me one bit, nor does it surprise me you are unaware of the
problems or orbital debris, wasteful launch operations and other
insanity and nuttiness. The Ares I rocket immediately comes to mind.

kT wrote:
Leopold Stotch wrote:
kT wrote

The foam problems still remain as the fundamental engineering science
of rocket science, something America has abandoned with Michael Griffin.


The "foam problem" is only a problem when you mount the crew vehicle
in tandem with the booster the way the STS does. Put the crew vehicle
on the top and shed foam till the cows come home, who cares? So long
as there is nothing important to hit foam shedding is not an issue.
Hell, put the CV on top and forget about putting foam on the thing at
all.

Actually, the foam problem is a universal orbital debris problem for all
upper stages and core stages that remain in orbit, or that are intended
to remain in orbit. For instance, you lose 60% - 75% of your payload
mass if you expend upper stages or in orbit, or in the case of core
stages, expend them after attaining 97% or more of orbital velocity.

The foam degrades in ultraviolet and creates a huge mess on orbit. If
you want to recycle those upper stages or core stages on orbit, the foam
problem must be solved. It's the number one problem of rocket science.

Of course, if you want to waste 60% to 75% of your payload, that's your
choice. Maybe it makes you so proud to be wasteful, and proud to neglect
the problems of rocket science as you have done these last eight years.
If you are an American, considering the state of America, it doesn't
surprise me one bit, nor does it surprise me you are unaware of the
problems or orbital debris, wasteful launch operations and other
insanity and nuttiness. The Ares I rocket immediately comes to mind.

I haven't seen any data that supports foam shedding being an orbital
debris issue. Frankly I doubt it. When you get into the upper
atmosphere, foam shedding should halt before you get to orbit. Even if
it didn't, foam has a low density and relatively high surface area so it
would not stay in orbit long.

That said, if you put the CV on the nose instead of tandem with the
booster I don't see the need for foam. Yes you will get some ice
loading, just as the Saturn V did. It shakes off within the first few
seconds.

Put the CV on the top and forget about the foam.

Note though, I am not saying the CV must be a capsule. You could do
a lifting body ( a la X-24 or HL-10 or the like) or some sort of winged
airframe. If you are not building a large cargo carrying vehicle I
don't that a nose mounted CV is incompatible with non-capsule
configurations.

Leopold Stotch wrote:
kT wrote:
Leopold Stotch wrote:
kT wrote

The foam problems still remain as the fundamental engineering
science of rocket science, something America has abandoned with
Michael Griffin.


The "foam problem" is only a problem when you mount the crew vehicle
in tandem with the booster the way the STS does. Put the crew
vehicle on the top and shed foam till the cows come home, who cares?
So long as there is nothing important to hit foam shedding is not an
issue. Hell, put the CV on top and forget about putting foam on the
thing at all.

Actually, the foam problem is a universal orbital debris problem for
all upper stages and core stages that remain in orbit, or that are
intended to remain in orbit. For instance, you lose 60% - 75% of your
payload mass if you expend upper stages or in orbit, or in the case of
core stages, expend them after attaining 97% or more of orbital velocity.

The foam degrades in ultraviolet and creates a huge mess on orbit. If
you want to recycle those upper stages or core stages on orbit, the
foam problem must be solved. It's the number one problem of rocket
science.

Of course, if you want to waste 60% to 75% of your payload, that's
your choice. Maybe it makes you so proud to be wasteful, and proud to
neglect the problems of rocket science as you have done these last
eight years. If you are an American, considering the state of America,
it doesn't surprise me one bit, nor does it surprise me you are
unaware of the problems or orbital debris, wasteful launch operations
and other insanity and nuttiness. The Ares I rocket immediately comes
to mind.

I haven't seen any data that supports foam shedding being an orbital
debris issue.

It's a first principles result.

Frankly I doubt it.

You can doubt all you want, it's a first principles result well backed
up by simple physics and chemistry.

When you get into the upper
atmosphere, foam shedding should halt before you get to orbit.

I'm not talking about big chunks of foam, I'm talking about ordinary uv
catalyzed hydrocarbon polymer chain degradation. I guess you never heard
of it, or never experienced it in real life. Ever been in the tropics?

Even if
it didn't, foam has a low density and relatively high surface area so it
would not stay in orbit long.

Sure, uh-huh. It's almost as stupid as painting spacecraft.

That said

You haven't said anything.

if you put the CV on the nose instead of tandem with the
booster I don't see the need for foam. Yes you will get some ice
loading, just as the Saturn V did. It shakes off within the first few
seconds.

That's what I'm talking about, we can use creative methods to eliminate
the foam entirely and that opens up an entire new regime of spaceflight.

In other words, on orbit recovery of engines and retrofitting of tanks.

Put the CV on the top and forget about the foam.

You still need to insulate the hydrogen tank while it sits on the
ground, and develop a method to recycle the boiloff during launch.

This is a non-trivial but eminently solvable problem of rocket science.

Note though, I am not saying the CV must be a capsule. You could do a
lifting body ( a la X-24 or HL-10 or the like) or some sort of winged
airframe. If you are not building a large cargo carrying vehicle I
don't that a nose mounted CV is incompatible with non-capsule
configurations.

Whatever. The real problem remains the foam on the tankage.

kT wrote:
Leopold Stotch wrote:
kT wrote:
Leopold Stotch wrote:
kT wrote

The foam problems still remain as the fundamental engineering
science of rocket science, something America has abandoned with
Michael Griffin.


The "foam problem" is only a problem when you mount the crew vehicle
in tandem with the booster the way the STS does. Put the crew
vehicle on the top and shed foam till the cows come home, who
cares? So long as there is nothing important to hit foam shedding
is not an issue. Hell, put the CV on top and forget about putting
foam on the thing at all.

Actually, the foam problem is a universal orbital debris problem for
all upper stages and core stages that remain in orbit, or that are
intended to remain in orbit. For instance, you lose 60% - 75% of your
payload mass if you expend upper stages or in orbit, or in the case
of core stages, expend them after attaining 97% or more of orbital
velocity.

The foam degrades in ultraviolet and creates a huge mess on orbit. If
you want to recycle those upper stages or core stages on orbit, the
foam problem must be solved. It's the number one problem of rocket
science.

Of course, if you want to waste 60% to 75% of your payload, that's
your choice. Maybe it makes you so proud to be wasteful, and proud to
neglect the problems of rocket science as you have done these last
eight years. If you are an American, considering the state of
America, it doesn't surprise me one bit, nor does it surprise me you
are unaware of the problems or orbital debris, wasteful launch
operations and other insanity and nuttiness. The Ares I rocket
immediately comes to mind.

I haven't seen any data that supports foam shedding being an orbital
debris issue.

It's a first principles result.

Frankly I doubt it.

You can doubt all you want, it's a first principles result well backed
up by simple physics and chemistry.

When you get into the upper atmosphere, foam shedding should halt
before you get to orbit.

I'm not talking about big chunks of foam, I'm talking about ordinary uv
catalyzed hydrocarbon polymer chain degradation. I guess you never heard
of it, or never experienced it in real life. Ever been in the tropics?

Even if it didn't, foam has a low density and relatively high surface
area so it would not stay in orbit long.

Sure, uh-huh. It's almost as stupid as painting spacecraft.

The ET doesn't go into orbit. Some painted booster sections on the
other hand do. If the ET is emitting particles of external foam before
orbit is achieved those particles will either not make it to orbit or
will be in a low, short lived orbit. Either way, not a problem. If you
can source a document that details concerns about ET foam becoming an on
orbit debris problem I would be interested in reading them.


That said

You haven't said anything.

if you put the CV on the nose instead of tandem with the
booster I don't see the need for foam. Yes you will get some ice
loading, just as the Saturn V did. It shakes off within the first few
seconds.

That's what I'm talking about, we can use creative methods to eliminate
the foam entirely and that opens up an entire new regime of spaceflight.

In other words, on orbit recovery of engines and retrofitting of tanks.

Put the CV on the top and forget about the foam.

You still need to insulate the hydrogen tank while it sits on the
ground, and develop a method to recycle the boiloff during launch.

This is a non-trivial but eminently solvable problem of rocket science.

Note though, I am not saying the CV must be a capsule. You could do
a lifting body ( a la X-24 or HL-10 or the like) or some sort of
winged airframe. If you are not building a large cargo carrying
vehicle I don't that a nose mounted CV is incompatible with
non-capsule configurations.

Whatever. The real problem remains the foam on the tankage.

Sorry, I don't understand your hangup on the foam. We have several
perfectly good boosters that are sans external foam. The external foam
on the STS ET is purely an artifact of the tandem mounting of the CV
(with its fragile TPS) next to the ET. If you put the CV on top of the
booster stack you don't need the external foam. Saturn V didn't have
it, Delta IV doesn't have it, Atlas V doesn't have it. Neither do any
of the large Soviet/Russian boosters currently in service.

CV on top = no external foam
CV in tandem = external foam
External Foam + Tandem CV = Inherent danger to CV

Yes, we could probably put a lot of effort into materials research
to find a better (perhaps even much better) external foam which would
mitigate some of the danger inherent in a tandem CV/booster arrangement.
Or, you could pick an inherently safer arrangement and put the CV on
top of the booster stack and forget about external foam insulation
altogether. Second option sounds like better engineering to me.

On Wed, 31 Dec 2008 07:03:33 GMT, Leopold Stotch
wrote:



Sorry, I don't understand your hangup on the foam. We have several
perfectly good boosters that are sans external foam. The external foam
on the STS ET is purely an artifact of the tandem mounting of the CV
(with its fragile TPS) next to the ET. If you put the CV on top of the
booster stack you don't need the external foam. Saturn V didn't have
it, Delta IV doesn't have it, Atlas V doesn't have it. Neither do any
of the large Soviet/Russian boosters currently in service.

CV on top = no external foam
CV in tandem = external foam
External Foam + Tandem CV = Inherent danger to CV

Yes, we could probably put a lot of effort into materials research
to find a better (perhaps even much better) external foam which would
mitigate some of the danger inherent in a tandem CV/booster arrangement.
Or, you could pick an inherently safer arrangement and put the CV on
top of the booster stack and forget about external foam insulation
altogether. Second option sounds like better engineering to me.

OK, I know that if this were an actual idea, somebody smarter than I
would have had it already...

Why would the foam have to go on the outside of the tank at all? If
you put the foam on the inside of the tank walls, you don't have a
shedding problem. I know it's easier to build the tank, then spray
the foam on the outside of the completed unit, but still...

Does the tank get hot enough at launch (air friction/heat from the
engines) that it would weaken it if it weren't covered in foam?

take care,
Scott

On 30 Dec, 19:56, Fred J. McCall wrote:


You seem to think the tiles on the Shuttle are ablative protection.
They're not. *Hence, by your own implication, the shuttle must be
"potentially a solution".

If the tiles are non ablative it rather surprises me that no research
has been done on making a strong ceramic material. This is perfectly
possible to do. There are when all is said and done ceramic and carbon
fiber reinforced materials.

- Ian Parker

I am fascinated with the idea of taking all these main engines to
orbit for reuse?

now consider theres no easy way to fuel them, the launch environment
is very different than in orbit use after months or longer of sitting
around, and whats big enough to send into interplanetary space?

whats the payload?

"Fred J. McCall" wrote in message
...
"Jeff Findley" wrote:
:
:
:Furthermore, when you're talking about returning from the moon, the
ability
:to land at more than two locations (KSC and Edwards) is a good thing.
Also,
:resistance to bad weather during landing is more important, since you're
:committed to a landing time when you leave lunar orbit and weather has
much
:more time to turn bad in that situation than after a de-orbit burn in
LEO.
:

Why? Why couldn't you plan your return with an LEO insertion burn and
just sit up there until conditions were good?

Because of the huge delta-V requirements to do so. The Orion design
decision to discard the service module makes aerocapture, and subsequent
loitering in LEO and de-orbit burn, very difficult without a service module
attached.

If the Orion design did not throw away the service module, but instead
incorporated it into the capsule design, aerocapture and loitering in LEO
would at least be theoretically possible without a huge change to the
design. Such a capsule design would be a good candidate to make completely
reusable since you're not throwing away huge portions of your spacecraft to
destructively reenter.

Jeff
--
"Many things that were acceptable in 1958 are no longer acceptable today.
My own standards have changed too." -- Freeman Dyson

"Ian Parker" wrote in message
...
On 30 Dec, 19:56, Fred J. McCall wrote:


You seem to think the tiles on the Shuttle are ablative protection.
They're not. Hence, by your own implication, the shuttle must be
"potentially a solution".

If the tiles are non ablative it rather surprises me that no research
has been done on making a strong ceramic material. This is perfectly
possible to do. There are when all is said and done ceramic and carbon
fiber reinforced materials.

There has been research in this area, but the shuttle design does not lend
itself to retrofitting tougher tiles to the design. The added weight of
tougher tiles reduces payload by an equal amount.

Jeff
--
"Many things that were acceptable in 1958 are no longer acceptable today.
My own standards have changed too." -- Freeman Dyson

Scott Stevenson wrote:
On Wed, 31 Dec 2008 07:03:33 GMT, Leopold Stotch
wrote:


Sorry, I don't understand your hangup on the foam. We have several
perfectly good boosters that are sans external foam. The external foam
on the STS ET is purely an artifact of the tandem mounting of the CV
(with its fragile TPS) next to the ET. If you put the CV on top of the
booster stack you don't need the external foam. Saturn V didn't have
it, Delta IV doesn't have it, Atlas V doesn't have it. Neither do any
of the large Soviet/Russian boosters currently in service.

CV on top = no external foam
CV in tandem = external foam
External Foam + Tandem CV = Inherent danger to CV

Yes, we could probably put a lot of effort into materials research
to find a better (perhaps even much better) external foam which would
mitigate some of the danger inherent in a tandem CV/booster arrangement.
Or, you could pick an inherently safer arrangement and put the CV on
top of the booster stack and forget about external foam insulation
altogether. Second option sounds like better engineering to me.

OK, I know that if this were an actual idea, somebody smarter than I
would have had it already...

Why would the foam have to go on the outside of the tank at all? If
you put the foam on the inside of the tank walls, you don't have a
shedding problem. I know it's easier to build the tank, then spray
the foam on the outside of the completed unit, but still...

Does the tank get hot enough at launch (air friction/heat from the
engines) that it would weaken it if it weren't covered in foam?

take care,
Scott


You could have internal insulation, but that requires you to have a
double walled tank with foam in between the walls. This would incur a
significant weight penalty. If you put the foam internal to the tank
(without a double wall) you run the risk of foam chunks breaking loose
which would then get sucked into the turbo pumps which feed the engines,
which would make for a very bad day.

External heating of the tank during ascent is fortunately not an
issue. The foam is there to minimize ice formation which endangers the
thermal protection system (i.e. the tiles and reinforced carbon -
carbon) on the underside of the orbiter.

Basically, mounting a crew vehicle next to (i.e. in tandem with) a
cryogenic fuel tank is a problem due to the danger of ice or foam
shedding during ascent. It is possible that further work on the
insulation might one day result in a material that completely eliminates
ice formation and is not a hazard itself due to shedding, but it is a
hard problem that so far has not been solved. Mounting the crew vehicle
at the top of a vertically stacked booster (as in the Apollo and Soyuz
systems) is inherently safer, though it becomes somewhat unwieldy if you
want to build a really large vehicle which carries both crew and
significant cargo.