least polluting rocket fuel
pstu...@gmail.com
polluting than kerosene or hydrogen? If so, are any of them
economically feasible?
Roy Smith
pstu...@gmail.com wrote:
I can't imagine anything less polluting than hydrogen. The only possible
combustion product of hydrogen is water, regardless of temperature or mix
ratio.
no_one
are looking for. Why do you think that hydorgen is polluting? I would
think that the post combustion product was H2O.
<pstu...@gmail.com> wrote in message
news:1138202258.4...@z14g2000cwz.googlegroups.com...
Ten Quidado
> polluting than kerosene or hydrogen? If so, are any of them
> economically feasible?
>
Um, hydrogen isn't polluting. Rockets burning pure H2 and O2 generate
water.
Damon Hill
@z14g2000cwz.googlegroups.com:
> Are there any rocket fuels -- existing or potential -- that are less
> polluting than kerosene or hydrogen? If so, are any of them
> economically feasible?
Exactly how polluting are carbon dioxide and water?
There are no practical alternatives to existing chemistries.
If anything, it's not a problem to begin with; these
exhaust products are normal constituents of the atmosphere.
--Damon
Cra...@gmail.com
combination. The exhaust is water.
Mike Miller
Cruithne3753
Rick Jones
I'm neither a rocket scientist nor chemist, but my understanding is
that the combustion product of Hydrogen and Oxygen (I'm ass-u-me-ing
the rockets are using Oxygen as the oxidizer) is water and I suspect
that is about as "non-polluting" as it gets.
Unless perhaps we start talking about things like rails and
"beanstalks" and the like, but then those aren't devices using "rocket
fuel" right?
rick jones
--
portable adj, code that compiles under more than one compiler
these opinions are mine, all mine; HP might not want them anyway... :)
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
Ian Woollard
also be able to use some suitable vegetable oils to replace kerosene
with minimal modification to the engines. Doing it that way, you'd get
minimal pollution (a bit of nitrates produced during the burn, but not
too bad.)
Hydrogen is only less polluting if you make it in a non polluting way,
but hydrogen is actually commercially manufactured from methane; is
energy intensive and probably generates more CO2 than a rocket burning
kerosene would.
(Manufacturing hydrogen from electrolysis of water using nuclear power,
in principle is clean, but is never done on a large scale; the energy
required is prohibitive.)
Ian Stirling
Several people have mentioned this, but it's not quite true.
Of course, only water comes from the reaction of oxygen and hydrogen.
But, when a several km/s jet of any form hits air, it's quite hot and
energetic enough to cause nitrogen oxides to form.
G. R. L. Cowan
Actually water doesn't naturally tend to rise high in the stratosphere,
so its release there by rockets or aircraft can be considered pollution,
although not, in my opinion, of a very serious kind.
I believe it freezes and fairly soon falls out.
A rocket with liquid air for propellant,
powered by a laser on the ground,
would be a little cleaner than an oxyhydrogen rocket.
Isp probably would be much inferior,
although in principle one could put a lot of laser
power into heating a low mass flow rate of air
from the rocket's tanks, and get a crazy chamber temperature
in the middle of the chamber but not at the walls.
--- Graham Cowan, former hydrogen fan
Boron fire good. http://tinyurl.com/4xt8g
Jim Logajan
I'm surprised no one has suggested solar power. ;-)
A simple ground or space based variable-focus mirror and a solar-heated
ramjet is all you need! Needs, ah, a few details worked out....
Cra...@gmail.com
G. R. L. Cowan wrote:
> A rocket with liquid air for propellant,
> powered by a laser on the ground,
> would be a little cleaner than an oxyhydrogen rocket.
If you kept the liquid air fairly cool when you zap it with a laser,
sure. However, if you heat that liquid air with the laser to several
thousand degrees, you're probably going to get a lot of nitrous oxides.
Mike Miller
Patrick Schaaf
>(Manufacturing hydrogen from electrolysis of water using nuclear power,
>in principle is clean,
Yeah. And the nuclear waste will be flung, using beanstalks made
of hemp, right into the sun, where it can again be called nonpolluting...
best regards
Patrick
Sea Wasp
> Are there any rocket fuels -- existing or potential -- that are less
> polluting than kerosene or hydrogen?
HYDROGEN???
When hydrogen burns, it releases H2O. While the dangers of dihydrogen
oxide (more commonly called "water") are well known, it is generally
not considered a pollutant.
--
Sea Wasp
/^\
;;;
Live Journal: http://www.livejournal.com/users/seawasp/
Ian Woollard
manufacture; and a lot of CO2 and doubtless other pollutants get
generated. The fact that it produces very little pollution when the
rocket flies isn't really the point.
Fuels like bioethanol and don't produce net CO2 since the plants suck
an equal amount of CO2 out of the air when they grow, so you're left
with essentially no pollution - from the fuel anyway.
The rocket itself is a different story- aluminium needs quite a bit of
energy to produce and CO2 is liberated during the electrolysis that
makes it from the ore. Still, a BOTE calculation suggests that this is
a much smaller amount of pollution than the fuel.
Lawrence Gales
On Fri, 27 Jan 2006, Ian Woollard wrote:
> Date: 27 Jan 2006 18:23:01 -0800
> From: Ian Woollard <ian.wo...@gmail.com>
> Newsgroups: sci.space.tech
> Subject: Re: least polluting rocket fuel
-----------------------------------------------
It is my undestanding that current large wind turbines create electricity
at 4.5 cent/KWH (with no subsidies) on the average. At that rate it costs
about $2 to produce an amount of H2 by electrolysis which, when burned in
a fuel cell, is
equal to a gallon of gasoline, when burned in a combustion engine. For
automobile use you have to add another dollar for all the remaining costs
of distribution, including profits. So $3/gallon equivalent of gasoline
to produce H2 by electrolysis is hardly prohibitive
In fact the costs would be lower, because the 4.5 cents/KWH assume that
you are using *clean* electricity to perform electrolysis. A major part
of wind turbine costs is the conversion of mixed frequency current to
direct current and then back to clean 60 cycle current -- something that
is needed to run computers and TVs but not for electrolysis.
I don't know why this myth of high costs to clenaly produce H2 persists.
However,
H2 is only truly clean when burned in a fuel cell. When burned using
combution it produces Nitrogen oxides.
-- Larry Gales
David M. Palmer
<mailer...@bof.de> wrote:
What? And upset the delicate ecology that may exist on the Sun? After
you've polluted the Sun, an unprotected person standing on the surface
would quickly die of radiation (even if they go at night).
--
David M. Palmer dmpa...@email.com (formerly @clark.net, @ematic.com)
Ian Woollard
'gallon equivalent' is 1kg of hydrogen and would in fact cost slightly
over $4 to produce by electrolysing water. However, for rocketry
purposes this neglects the liquification costs which are quite
significant.
Last time I heard, NASA was purchasing their *liquid* hydrogen for
about $7/kg, and that wasn't even environmentally friendly hydrogen,
which is more expensive.
Damon Hill
news:1139547603....@g44g2000cwa.googlegroups.com:
So the only acceptable propellants are wind/solar powered
electrolytically derived and liquified hydrogen and oxygen?
We certainly don't want nuclear-comtaminated fuels, do we?
(sarcasm)
--Damon
Ian Woollard
most expensive propellant you can find, because that helps keeps the
costs of rockets high, the launch volume low; and increases profits.
So on that basis nuclear produced hydrogen is a wonder fuel.
I was just pointing out that bioethanol was cheap to make sure that
everyone here avoids using it in their rockets. Obviously.
David M. Palmer
<damon...@comcast.not.retro.com> wrote:
What is the ISP of a LOX-whale oil rocket?
H2-PV NOW
Potentially there are an infinite number of rocket propellents with
minimally reacting emissions. A mass ejection system using an
acceleration means to eject any inert mass will obey Newton's law of
equal and opposite reaction. If you were smart enough you could eject
sand, or marshmallows, or watermelons, fast enough to get a forward
thrust from it.
Most people aren't smart enough, so they use chemical explosives to
accomplish the task, beginning with gunpowder being used a thousand
years ago for Chinese rockets for warfare and fireworks displays.
Hydrogen Peroxide is an explosive used by some model rocketeers which
is fairly benign environmentally and quite capable of causing fatal
mishaps to the reckless experimenter.
As pointed out by many posters in this thread, Hydrogen and Oxygen as
fuel is fairly clean under many circumstances, although high volume
traffic in the Ozone layer might present a future problem, as Hydrogen
is very reactive with ozone, so imperfectly burned H2+O2 could
conceivably present a problem at this strata someday bye and bye.
Hydrogen by itself is not flamable. It requires oxidizer. H2+O2 outputs
significant heat, which causes atmospheric Nitrogen to react with
atmospheric Oxygen to make oxides of Nitrogen, called NOX, which
further react to produce photochemical smog.
Any sufficiently hot fire or flame will do this, so all fiery rocket
plumes do this to some extent no matter what is burning as fuel.
The problem is not so much a constant, as it is location dependent.
That is to say a rocket fired from ground level will have ten times the
density of air to react with as a rocket ignited at ten miles in
altitude, so the chemical reaction potential is ten times greater at
sea level.
There are proposals for balloon-assisted launches, or kite-assisted
launches at high altitudes, primarily for the purposs of saving fuel to
orbit, not as "clean" concepts. They would generate less NOX as a
byproduct of saving fuel, but that is not their intent.
NASA was able to loft a 1,600 pound plastic airplane to 96,863 feet in
2001, powered only by solar photovoltaic cells and 28 horsepower of
electric motors. That's 18.5 miles high, so there is some evidence that
high altitude launchpads are worth considering.
SpaceShipOne was launched from 50,000 feet from a flying platform on a
craft named White Knight, although it only attained a maximum height of
one-third the altitude to the International Space Station. That was
also a plastic rocket and plastic carrier plane. Perhaps if it launched
from the peak altitude of the NASA Helios record It might have reached
a low earth orbit.
The Take-Home Lesson should be that when you concern yourself about the
environmental effects you seem to get cheaper launches and better
results as a side-effect, or vice versa. Thinking cheaper produces less
environmental impacts as a side-effect. Ultimately there will be no
mass space transportation until people think a LOT CHEAPER. $10,000 per
pound Space Shuttle cargos is not the route we want to pursue any
longer than required to get the basic science data needed for $10/pound
payloads. Even $10/pound to deliver packages 220 miles is a lot more
than FedEx charges. 2,600,000 pounds of solid rocket exhaust makes a
1,300 tons of pollution. Think "CHEAPER" and you will get cleaner:
think "CLEANER" and you will get cheaper.