High strength fibers for hydrogen storage on the VentureStar.

On Sep 6, 11:30 pm, BradGuth wrote:
On Sep 6, 2:59 pm, Robert Clark wrote:
...
A nice retrospective article here discussing the DC-X attempt at a
reusable launch vehicle:

The legacy of DC-X.
by Jeff Foust
Monday, August 25, 2008http://thespacereview.com/article/1196/1

The progenitors of the DC-X project would dearly have loved to have
some higher energy fuel than LH2/LOX to allow them to succeed with
their single stage to orbit proposal but it's the highest one
practical. These propulsion experts are well aware of H2O2 as a
propellant and that it takes up much less volume than LH2 and that
it's simpler to store. But having to wring every last bit of weight
saving including the amount of required propellant to get to orbit
they were led to using LH2/LOX, as was every other proposal for using
rocket propulsion for a single stage to orbit vehicle. It's not
because they have some fixation on hydrogen as a fuel and they never
heard of other kinds.

Bob Clark

STTO is not a very practical alternative for accomplishing the most
payload to orbit, especially when those reusable boosters are clearly
the way to go, and even of those reusable boosters could be h2o2/
synfuel configured.

~ BG

The boosters now used to send payloads to orbit are all expendable
not reusable and there are no plans to have staged boosters to reach
orbit where all the stages would be reusable.
As I mentioned before the failure of the VentureStar single stage to
orbit system (SSTO) was because of the relatively trivial problem of
debonding of the composite liquid hydrogen tanks.

Bob Clark

On Sep 6, 11:30 pm, BradGuth wrote:
...

STTO is not a very practical alternative for accomplishing the most
payload to orbit, especially when those reusable boosters are clearly
the way to go, and even of those reusable boosters could be h2o2/
synfuel configured.

~ BG

It has been estimated that reusable launch vehicles would reduce the
costs to space from the current $10,000/kilo to $1,000/kilo.
There is a lot of debate on space forums about whether decreasing the
cost to space to 1/10th the current price would increase the market
for launches, but I can give an argument it would increase the market
for passenger flights: at $1,000 per kilo the cost for a 100 kilo
passenger would be $100,000, but at $10,000 per kilo the price would
be $1,000,000. Very many even middle class people could afford to get
a loan for a $100,000 cost, as it is for example comparable to the
cost of buying just an average size home. Very few people on the other
hand could afford to get a loan for $1,000,000. Also very many
universities and colleges could afford to pay a price of $100,000 to
send one of their researchers to space, while few would be willing to
pay $1,000,000 to do so.
There is also the fact that the Bigelow Space Hotels would give the
passengers some place to go to rather than just going to orbit for a
few hours and returning.


Bob Clark

On Sep 7, 2:59 pm, Robert Clark wrote:
On Sep 7, 10:56 am, wrote:



On Jul 29, 12:59 pm, Robert Clark wrote:

You could store it as high density gas.
Bob Clark

The hydrogen would be too low of density to be of use for launch
vehicles. It has to be liquiefied. Do your research.

On Sep 7, 10:24 am, Robert Clark wrote:

I'm suggesting that storage in the form of numerous containers at the
microscale using high strength materials we already have would solve
this problem. Because of the increase of strength to weight of the
highest strength materials at the microscale you could reduce the
weight of the tanks up to a factor of a 100. The weight of the tanks
would become essentially nothing.
Bob Clark

totally nonplausible. This is not a solution. Numerous containers
would have numerous attach fittings and numerous plumbing fixtures and
pipes. This would offset any weight savings (not that the tanks are
viable in the first place) Not to mention dealing with propellant
management.

the tanks were not the only problem with the X-33.

Clark, stick to something that you know (which isn't rocket science)
and leave the engineering to the experts.

The failure of the light-weight liquid hydrogen tanks was THE main
reason the VentureStar was canceled:

X-33/VentureStar - What really happened.http://www.nasaspaceflight.com/content/?id=4180

As I stated in the first posts of this thread, the intent of using
microtubes or microspheres made of high strength materials WAS for the
*liquid* hydrogen and oxygen tanks of the reusable launch vehicles.
The highest strength materials would reduce the weight of the tanks by
a factor of a 100 to 1.
If research into hydrogen gas storage for hydrogen powered cars using
microspheres or microtubes was investigated this would give an
incentive for investigating their use for tanks on reusable launch
vehicles. The reduction in weight of one part of the vehicle's
structure from 60,000 pounds out of a total weight of 250,000 pounds
to only 600 pounds would be a major improvement in weight.
As I mentioned before in the thread there are several different ways
of doing it where you wouldn't have to use separate, individual pipe
fittings or valves for each of the separate micro tubes or spheres.
For instance there is ongoing research on using glass microspheres for
hydrogen storage for cars where obviously the scientists involved
don't intend to attach separate valves to each microsphere only
microns across.
The structure of the tanks consisting of millions of microtubes or
microspheres might appear radical at first but if you think about it
just means you are using a tank whose internal structure is porous
like a sponge and the strength of the tank is coming from the millions
of horizontal and vertical internal layers of the tank rather the
tank's one single outer surface. Indeed there is research on using
sponge-like materials for hydrogen storage:

Press Release 06-043
New "Crystal Sponge" Triples Hydrogen Storage
UCLA, University of Michigan chemists advance hydrogen as fuel for
cars and electronic devices.http://www.nsf.gov/news/news_summ.jsp?cntn_id=106757

Notably this advance only achieves 7.5 percent hydrogen gas storage
and only at liquid nitrogen temperatures of 77 K. The high strength
materials at the microscale I was suggesting would be able to get 57
percent hydrogen gas storage and at room temperature. If these high
strength microscale materials only had to do the storage at 77 K, then
they would be able to achieve over 90 percent hydrogen storage since
less pressure, and less thickness of the walls, would be required to
get the hydrogen to the density level of the DOE requirements.

Bob Clark

Such large capacity as hosting volumes of highly insulated tankage,
and of the required structural bindings along with greater flow
capacity of piping infrastructure = inert mass.

Dead or unusable fuel also = inert mass.

A composite formulated tank would tend to minimize such inert mass
considerations.

~ Brad Guth Brad_Guth Brad.Guth BradGuth

On Sep 7, 3:40 pm, Robert Clark wrote:
On Sep 6, 11:30 pm, BradGuth wrote:

...

STTO is not a very practical alternative for accomplishing the most
payload to orbit, especially when those reusable boosters are clearly
the way to go, and even of those reusable boosters could be h2o2/
synfuel configured.

~ BG

It has been estimated that reusable launch vehicles would reduce the
costs to space from the current $10,000/kilo to $1,000/kilo.

China already offers CATS, at perhaps as little cost as $1000/kg.

There is a lot of debate on space forums about whether decreasing the
cost to space to 1/10th the current price would increase the market
for launches, but I can give an argument it would increase the market
for passenger flights: at $1,000 per kilo the cost for a 100 kilo
passenger would be $100,000, but at $10,000 per kilo the price would
be $1,000,000. Very many even middle class people could afford to get
a loan for a $100,000 cost, as it is for example comparable to the
cost of buying just an average size home. Very few people on the other
hand could afford to get a loan for $1,000,000. Also very many
universities and colleges could afford to pay a price of $100,000 to
send one of their researchers to space, while few would be willing to
pay $1,000,000 to do so.
There is also the fact that the Bigelow Space Hotels would give the
passengers some place to go to rather than just going to orbit for a
few hours and returning.

Bob Clark

I tend to like those Bigelow Space Hotels, especially if a group of
such inflated modules were to cerate POOF City at Venus L2.

~ Brad Guth Brad_Guth Brad.Guth BradGuth

Robert Clark wrote:
On Sep 6, 11:30 pm, BradGuth wrote:

...

STTO is not a very practical alternative for accomplishing the most
payload to orbit, especially when those reusable boosters are clearly
the way to go, and even of those reusable boosters could be h2o2/
synfuel configured.

~ BG


It has been estimated that reusable launch vehicles would reduce the
costs to space from the current $10,000/kilo to $1,000/kilo.


It went a lot further down than that IIRC in the early days of the
Shuttle program; I seem to remember $200.00 per kilo being batted around.

Pat

In article
,
Robert Clark wrote:

snip

However, I understand that when reading it on a Usenet news reader
they get separated when you change the subject line so I'll avoid
doing that.

Only in some newsreaders; the more capable ones can be configured to
thread articles by reference, more or less the same way that Google does.

--
Odysseus

On Sep 6, 7:26*am, Robert Clark wrote:
On Aug 19, 12:21 pm, wrote:

Hoop stresses of a tube under pressure increase with the diameter but
volume increases with the square of diameter. High volume/weight
pressurised gas storage would, therefore, favor a bigger cylinder.
At the 1e-21 barvacuumof our Selene/moon L1, the volume and/or
tonnage of that hydrogen gas storage is unlimited.

Several times I tried to design alighterthanairvacuumstructure --
a _really_ worthless project -- but no material was strong/light
enough except maybe C nanotubes. *All three times I determined that
there was no advantage either in scaling up or down. *I somehow forgot
my own conclusion. *Again.

Bret Cahill

*After a web search I found a report on creating inflatable vacuum
chambers, where the walls are filled with pressurized gas for
strength. Such chambers could even be buoyant if the walls were filled
with a lighter than air gas such as helium:

Stability Analysis of an Inflatable Vacuum Chamber.http://arxiv.org/abs/physics/0610222v4

*In experiments discussed in the report the chamber failed. But the
researchers believe this is because of the failure of the epoxy
joining the separate pressurized tubes that made up the chamber walls.

* *Bob Clark

The author of that report presents calculations that compressional
strength such as what you would need for the walls of a vacuum chamber
can be obtained by making the walls consist of pressurized tubes with
skin made out of materials with high tensional strength. Then
presumably you could get as high a compressional strength as these
materials have in tensional strength. The idea is similar to the fact
that a basketball will have high compressional strength coming from
the pressurized gas inside and the high strength of the material
against stretching.
Using this method and microtubes of tensile strength as high as 60
GPa, or 600,000 bar, you could get compressional strength this high as
well. This would be over a hundred times the strength to weight ratio
of the steel or aluminum alloys used for the structure of the
spacecraft or of other mostly metal structures.
Imagine the spacecraft instead of weighing 250,000 pounds weighing
only 2,500 pounds. Or a car instead of weighing 2,000 pounds, only
weighing 20.


Bob Clark

On Sep 10, 6:11 pm, Robert Clark wrote:
On Sep 6, 7:26 am, Robert Clark wrote:



On Aug 19, 12:21 pm, wrote:

Hoop stresses of a tube under pressure increase with the diameter but
volume increases with the square of diameter. High volume/weight
pressurised gas storage would, therefore, favor a bigger cylinder.
At the 1e-21 barvacuumof our Selene/moon L1, the volume and/or
tonnage of that hydrogen gas storage is unlimited.

Several times I tried to design alighterthanairvacuumstructure --
a _really_ worthless project -- but no material was strong/light
enough except maybe C nanotubes. All three times I determined that
there was no advantage either in scaling up or down. I somehow forgot
my own conclusion. Again.

Bret Cahill

After a web search I found a report on creating inflatable vacuum
chambers, where the walls are filled with pressurized gas for
strength. Such chambers could even be buoyant if the walls were filled
with a lighter than air gas such as helium:

Stability Analysis of an Inflatable Vacuum Chamber.http://arxiv.org/abs/physics/0610222v4

In experiments discussed in the report the chamber failed. But the
researchers believe this is because of the failure of the epoxy
joining the separate pressurized tubes that made up the chamber walls.

Bob Clark

The author of that report presents calculations that compressional
strength such as what you would need for the walls of a vacuum chamber
can be obtained by making the walls consist of pressurized tubes with
skin made out of materials with high tensional strength. Then
presumably you could get as high a compressional strength as these
materials have in tensional strength. The idea is similar to the fact
that a basketball will have high compressional strength coming from
the pressurized gas inside and the high strength of the material
against stretching.
Using this method and microtubes of tensile strength as high as 60
GPa, or 600,000 bar, you could get compressional strength this high as
well. This would be over a hundred times the strength to weight ratio
of the steel or aluminum alloys used for the structure of the
spacecraft or of other mostly metal structures.
Imagine the spacecraft instead of weighing 250,000 pounds weighing
only 2,500 pounds. Or a car instead of weighing 2,000 pounds, only
weighing 20.

Bob Clark

Say whatever you may, h2o2+synfuel is still not a bad way to fly-by-
rocket go, and go, and go.

~ BG

On Sep 10, 9:11*pm, Robert Clark wrote:
On Sep 6, 7:26*am, Robert Clark wrote:



On Aug 19, 12:21 pm, wrote:

Hoop stresses of a tube under pressure increase with the diameter but
volume increases with the square of diameter. High volume/weight
pressurised gas storage would, therefore, favor a bigger cylinder..
At the 1e-21 barvacuumof our Selene/moon L1, the volume and/or
tonnage of that hydrogen gas storage is unlimited.

Several times I tried to design alighterthanairvacuumstructure --
a _really_ worthless project -- but no material was strong/light
enough except maybe C nanotubes. *All three times I determined that
there was no advantage either in scaling up or down. *I somehow forgot
my own conclusion. *Again.

Bret Cahill

*After a web search I found a report on creating inflatable vacuum
chambers, where the walls are filled with pressurized gas for
strength. Such chambers could even be buoyant if the walls were filled
with a lighter than air gas such as helium:

Stability Analysis of an InflatableVacuum Chamber.http://arxiv.org/abs/physics/0610222v4

*In experiments discussed in the report the chamber failed. But the
researchers believe this is because of the failure of the epoxy
joining the separate pressurized tubes that made up the chamber walls.

* *Bob Clark

* The author of that report presents calculations that compressional
strength such as what you would need for the walls of avacuum chamber
can be obtained by making the walls consist of pressurized tubes with
skin made out of materials with high tensional strength. Then
presumably you could get as high a compressional strength as these
materials have in tensional strength. The idea is similar to the fact
that a basketball will have high compressional strength coming from
the pressurized gas inside and the high strength of the material
against stretching.
*Using this method and microtubes of tensile strength as high as 60
GPa, or 600,000 bar, you could get compressional strength this high as
well. This would be over a hundred times the strength to weight ratio
of the steel or aluminum alloys used for the structure of the
spacecraft or of other mostly metal structures.
*Imagine the spacecraft instead of weighing 250,000 pounds weighing
only 2,500 pounds. Or a car instead of weighing 2,000 pounds, only
weighing 20.

* *Bob Clark

If this method can be made to work then such lightweight vacuum
chambers could be used to maintain the low temperatures required for
liquid hydrogen through the high vacuum as insulation. Then this might
allow the light weight, high density hydrogen storage required for the
hydrogen economy without requiring the complex, expensive systems now
used to keep the hydrogen at the cryogenic temperatures of liquid
hydrogen.
Likewise it would reduce the weight and complexity of the liquid
hydrogen storage for orbital launchers.

Bob Clark

On Sep 19, 9:17 am, Robert Clark wrote:
On Sep 10, 9:11 pm, Robert Clark wrote:



On Sep 6, 7:26 am, Robert Clark wrote:

On Aug 19, 12:21 pm, wrote:

Hoop stresses of a tube under pressure increase with the diameter but
volume increases with the square of diameter. High volume/weight
pressurised gas storage would, therefore, favor a bigger cylinder.
At the 1e-21 barvacuumof our Selene/moon L1, the volume and/or
tonnage of that hydrogen gas storage is unlimited.

Several times I tried to design alighterthanairvacuumstructure --
a _really_ worthless project -- but no material was strong/light
enough except maybe C nanotubes. All three times I determined that
there was no advantage either in scaling up or down. I somehow forgot
my own conclusion. Again.

Bret Cahill

After a web search I found a report on creating inflatable vacuum
chambers, where the walls are filled with pressurized gas for
strength. Such chambers could even be buoyant if the walls were filled
with a lighter than air gas such as helium:

Stability Analysis of an InflatableVacuum Chamber.http://arxiv.org/abs/physics/0610222v4

In experiments discussed in the report the chamber failed. But the
researchers believe this is because of the failure of the epoxy
joining the separate pressurized tubes that made up the chamber walls.

Bob Clark

The author of that report presents calculations that compressional
strength such as what you would need for the walls of avacuum chamber
can be obtained by making the walls consist of pressurized tubes with
skin made out of materials with high tensional strength. Then
presumably you could get as high a compressional strength as these
materials have in tensional strength. The idea is similar to the fact
that a basketball will have high compressional strength coming from
the pressurized gas inside and the high strength of the material
against stretching.
Using this method and microtubes of tensile strength as high as 60
GPa, or 600,000 bar, you could get compressional strength this high as
well. This would be over a hundred times the strength to weight ratio
of the steel or aluminum alloys used for the structure of the
spacecraft or of other mostly metal structures.
Imagine the spacecraft instead of weighing 250,000 pounds weighing
only 2,500 pounds. Or a car instead of weighing 2,000 pounds, only
weighing 20.

Bob Clark

If this method can be made to work then such lightweight vacuum
chambers could be used to maintain the low temperatures required for
liquid hydrogen through the high vacuum as insulation. Then this might
allow the light weight, high density hydrogen storage required for the
hydrogen economy without requiring the complex, expensive systems now
used to keep the hydrogen at the cryogenic temperatures of liquid
hydrogen.
Likewise it would reduce the weight and complexity of the liquid
hydrogen storage for orbital launchers.

Bob Clark

Or you could just as easily use plain old h2o2+synfuel, at least for
the reusable liquid fueled boosters.

~ BG