Re: The Five-Billion-Star Hotel / propulsion
Indeed, there are a number of propellants that are feasible.
So the "problem" is not the fuel, it is to get the funds
available - probably billions of dollars are required -
to design and develop and test-fly and produce and operate
a passenger-carrying vehicle so as to achieve "airline"
operations, which are known to bring costs down a long way.
Those who run space agencies have spent $1 trillion of our
money so far without having reduced the cost of space travel
by a single cent over more than 40 years - a historical record.
These people take the line that, even without spending even
as much as $1 million (which would be 1 millionth of what
they have spent on other subjects), to study the possibility,
they know so well that it is not feasible that it is much
better NOT to spend any funds at all to even study whether
it might be possible....
As a taxpayer, do you agree with this? Do you trust that
these people have your best interests at heart? Do you think
they have saved your money by not wasting it on such "pointless"
studies? Do you think the $1 trillion which they have spent
creating a "space industry" with a turnover of about 1/50th of
that investment, has been well spent?
I, for one, do not. I believe that it is certain that
by spending a few billion dollars, and making use of
some of the avalanche of new technology created since
Sputnik 1, passenger space travel costs could be reduced
very substantially - probably by more than 99%, which
will have a wide range of benefits.
Patrick Collins
> Ellen,
>
> Ellen Hughes wrote:
> > What would you say is a "safe" fuel for space flight?
>
> Kerosene/Jet fuel is probably one of the safer liquid fuels used in spaceflight.
> That is why it is used so much in early manned spaceflight.
> But your question is the wrong question. A fuel itself isn't inherently safe or
> hazardous, but when it is in close proximity to an oxidizer and a heat source,
> then the same thing that makes it an energetic propellant also makes it an
> energetic explosive. Just like with any other engine control and isolation of
> fuel and oxidizer make for better safety and reliability.
>
> A hybrid solid engine, where the oxidizer in pumped through the fuel core, can
> be throttled up or down or turned off, nearly instantainiously, like a liquid
> propellant engine. You can ship a fuel only hybrid core without concern that it
> might blow up (not so with an SRB.) A hybrid core fuel might be nothing more
> than a type of rubber or asphalt. Sure it could be caught on fire, but it would
> take an effort to do so and then it would burn rather slowly and not very hot.
> If you ever get the chance to visit Thikol's manufacturing facility in Utah, you
> would see how careful they are to ensure no ignition source comes anywhere near
> the facility.
>
> Cryogenic fuels and oxidizers have the additional hazard of instantly freezing
> anything they come in contact with, making most materials very brittle.
>
> And then there are the mono-propellants, which don't require an oxidizer to
> ignite, just a heat source. They tend to be highly toxic as well. They are
> usually only used for in-space propulsion only.
>
> Then there are oxidizers that act like fuels. Hydrogen Peroxide in high
> concentrations is one of these. Some claim that by using a catalyst can make
> Hydrogen Peroxide safe to use as a propellant, but handling the stuff on the
> ground is still quite dangerous.
>
> Not much in traditional rocketry tends to lend itself inherently to safety, as
> performance is always at a premium. The aircraft and automotive industries
> spend a lot of money trying to optimize performance and safety in their fuels,
> so it isn't any easier in space propulsion.
>
> --
> Mark Reiff <markreiff@xxxxxxxxxxxxx>
>
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