Fluorine Drive

I was thinking about Space exploration (as
usual), when I noted an interesting article on
the Wikipedia

http://en.wikipedia.org/wiki/Rocket_fuel

It mentions "The highest specific impulse
chemistry ever test-fired in a rocket engine was
lithium and fluorine, with hydrogen added to
improve the exhaust thermodynamics (making this a
tripropellant). The combination delivered 542
seconds (542 lbf·s/lb, 5.32 kN·s/kg, 5320 m/s)
specific impulse in a vacuum."

The specific impulse is a measure of propellant
performance hydrogen/oxygen has 460 seconds.
Due to the conditions small changes in specific
impulse give much bigger returns over the ratio
of IPS.

So why not use fluorine ? Well the rocket
exhaust is highly toxic. If you have to destroy
the rocket incase of emergency then you get even
more toxic elements.

One potential solution would be to forget
launching the whole rocket using whole
fluorine,lithium,hydrogen(FLH) propellant.

Why not launch a fluorine,lithium,hydrogen(FLH)
third stage on top of a normal
hydrogen/Kerosen/oxygen booster. The third stage
would then fire outside the earth's atmosphere
not polluting.

This would give quite a good insertion boost, but
ignores the problem of what happens if the
booster has to be (unfortunately) self destroyed ?

So this is my solution. Take off with the third
stage fuel of an inert lithium and fluorine
compound. Once safely in orbit the solar cells
are deployed (needed for the command space). The
solar cells power a small package which turns the
inter compound into the fuel. This runs for a
number of weeks until all the inert compound
turns into fuel.

When complete the crew are launched separately(
as per current NASA plan) the crew transfer to
mars transfer vehicle. The fluorine, lithium,
hydrogen(FLH) propellant is started up and the
crew go to Mars.

Confused ?

Let use an analgy - imagine if hydrogen and
oxygen where poisonous materials. Launch a third
stage to orbit full of water (the safe compound).
In orbit electrolyze the water back into hydrogen
and oxygen ( then cool it down and liquefy both
gases). A bit too much effort with non poisonous
fules.

Alternatives

a) While in orbit convert Oxygen to Ozone.
b) Use a space station to hold and process the ingredients before launch.

see http://www.braeunig.us/space/propel.htm for info