High strength fibers for hydrogen storage on the VentureStar.

On Sep 6, 3:36 pm, BradGuth wrote:
On Sep 6, 10:51 am, Robert Clark wrote:
...
H2O2 and other monopropellants are used for station keeping on
satellites because they have to be stored long periods. Here of course
you don't need a large velocity change, as required to get to orbit,
so the amount of fuel required is much less and you can make do with a
lower energy fuel.
However, the weight penalty would be too large if you wanted to use
it as propellant for a reusable launch vehicle where you can just
barely make it with a high energy fuel like hydrogen.

Bob Clark

You use funny math, and the avoidance and/or exclusion of whatever
rocks your boat.

Why do you and William Mook continually insist upon strictly a mono
propellant usage of h2o2? (are you related to one another?)

You’re saying we can forget about whatever’s the all-inclusive GLOW
inert mass (just like in those good old DARPA Apollo days of hocus-
pocus science as based upon conditional physics), including ice
loading and of whatever becomes unusable or evaporated fuel.

...

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, 2008
http://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

Robert Clark wrote:
For getting to orbit you want the propellant that gives the greatest
thrust for the weight. This is measured by the Isp (specific impulse).
The amount of fuel needed to shows a exponential dependence on the
Isp, though in an inverse fashion: if your Isp is smaller there will
be an exponential increase in the fuel required.
The Isp of hydrogen/oxygen engines is about 450 s, while that for
hydrogen peroxide as a monopropellant it's about 150 s, and for use as
an oxidizer with another fuel such as kerosene it's about 320 s.


Still, with H2O2 you save a lot of tankage weight versus LH2/LOX due to
the low density of LH2, and avoid the possible need to insulate the
propellant tanks, with that added weight on the vehicle.
I was always amazed by the small size of the Black Arrow launch vehicle
(it wasn't much bigger than a V-2), which used H2O2 and kerosene for
propellants, but was capable of putting a satellite into polar orbit.
It also had about the cleanest burning exhaust I ever laid eyes on:
http://www.geocities.com/CapeCanaver...6133/arrow.jpg

Pat

On Sep 6, 4:57 pm, Pat Flannery wrote:
Robert Clark wrote:
For getting to orbit you want the propellant that gives the greatest
thrust for the weight. This is measured by the Isp (specific impulse).
The amount of fuel needed to shows a exponential dependence on the
Isp, though in an inverse fashion: if your Isp is smaller there will
be an exponential increase in the fuel required.
The Isp of hydrogen/oxygen engines is about 450 s, while that for
hydrogen peroxide as a monopropellant it's about 150 s, and for use as
an oxidizer with another fuel such as kerosene it's about 320 s.

Still, with H2O2 you save a lot of tankage weight versus LH2/LOX due to
the low density of LH2, and avoid the possible need to insulate the
propellant tanks, with that added weight on the vehicle.
I was always amazed by the small size of the Black Arrow launch vehicle
(it wasn't much bigger than a V-2), which used H2O2 and kerosene for
propellants, but was capable of putting a satellite into polar orbit.
It also had about the cleanest burning exhaust I ever laid eyes on:http://www.geocities.com/CapeCanaver...6133/arrow.jpg

Pat

Very good feedback, not to mention the lower aerodynamic drag, lack of
ice loading and the nearly 100% fuel burn that only further reduces
inert mass.

h2o2 along with a better than kerosene synfuel can kick serious rocket
butt.

~ BG

On Sep 6, 2:59 pm, Robert Clark wrote:
On Sep 6, 3:36 pm, BradGuth wrote:



On Sep 6, 10:51 am, Robert Clark wrote:
...
H2O2 and other monopropellants are used for station keeping on
satellites because they have to be stored long periods. Here of course
you don't need a large velocity change, as required to get to orbit,
so the amount of fuel required is much less and you can make do with a
lower energy fuel.
However, the weight penalty would be too large if you wanted to use
it as propellant for a reusable launch vehicle where you can just
barely make it with a high energy fuel like hydrogen.

Bob Clark

You use funny math, and the avoidance and/or exclusion of whatever
rocks your boat.

Why do you and William Mook continually insist upon strictly a mono
propellant usage of h2o2? (are you related to one another?)

You’re saying we can forget about whatever’s the all-inclusive GLOW
inert mass (just like in those good old DARPA Apollo days of hocus-
pocus science as based upon conditional physics), including ice
loading and of whatever becomes unusable or evaporated fuel.

...

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

On Sep 6, 7:57 pm, Pat Flannery wrote:
Robert Clark wrote:
For getting to orbit you want the propellant that gives the greatest
thrust for the weight. This is measured by the Isp (specific impulse).
The amount of fuel needed to shows a exponential dependence on the
Isp, though in an inverse fashion: if your Isp is smaller there will
be an exponential increase in the fuel required.
The Isp of hydrogen/oxygen engines is about 450 s, while that for
hydrogen peroxide as a monopropellant it's about 150 s, and for use as
an oxidizer with another fuel such as kerosene it's about 320 s.

Still, with H2O2 you save a lot of tankage weight versus LH2/LOX due to
the low density of LH2, and avoid the possible need to insulate the
propellant tanks, with that added weight on the vehicle.
I was always amazed by the small size of the Black Arrow launch vehicle
(it wasn't much bigger than a V-2), which used H2O2 and kerosene for
propellants, but was capable of putting a satellite into polar orbit.
It also had about the cleanest burning exhaust I ever laid eyes on:http://www.geocities.com/CapeCanaver...6133/arrow.jpg

Pat

Yes, all kinds of fuels can be used for staged, disposable rockets,
as the Black Arrow was. The first stage engines of the Saturn V also
used kerosene, with LOX as the oxidizer.
But for reusable launch vehicles with rocket propulsion you have to
optimize the energy from the propellants such as by using hydrogen
fuel (an airbreather since it doesn't have to carry the oxidizer could
use a less energetic fuel than hydrogen.)
The reports on the cancellation of the VentureStar suggests it was
only the failure to get the lightweight hydrogen tanks to work that
caused its cancellation, a relatively trivial problem compared to the
complexity of the entire system.
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. It would be comparable to the weight
of the paint on the vehicle. Since the weight of the empty tanks can
be as large as 1/4 of the weight of the empty vehicle this would be a
major weight saving. Quite likely the other reusable launch vehicle
proposals would also become viable.
There has been some discussion on some space forums that the launch
providers have no incentive to produce reusable launch vehicles since
it would cut into their profit margins.
Since use of such high strength microspheres or microfibers might
provide a solution to the problem of storage of hydrogen for the
hydrogen-economy, this might provide a reason to investigate them for
that purpose which would also thereby make possible the goal of
reusable launch vehicles.


Bob Clark

On Sep 6, 2:56*pm, Robert Clark wrote:


*Obviously it's not *only* from fossil fuels. Expect the production
from alternative sources to increase.

* *Bob Clark

It is only from fossil fuel. There are no nuclear powered
electrolyzation plants

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.

"Robert Clark" wrote in message
...

STOP CHANGING THE SUBJECT LINE!!!

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

On Sep 7, 1:13 pm, "Alan Erskine" wrote:
"Robert Clark" wrote in message

...

STOP CHANGING THE SUBJECT LINE!!!

I'm reading this on groups.google.com where all the responses appear
on the same thread even though you change the subject line. I wanted
to emphasize that this method of storage would make possible all the
different proposals submitted to NASA for reusable launch vehicles not
just the VentureStar. So you would have several different types that
would be flying at the same time thus providing incentive to increase
the innovation in the vehicles and to have competition in lowering the
costs to space.
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.

Bob Clark