[ExI] big dumb booster question

[spike]

> ...On Behalf Of Jeff Davis
> ...
> Later I learned that the JATO used asphalt as fuel, tar basically.
> Mixed with some oxidizer, of course.
> 
> Question: Would it be functionally possible to use asphalt as 
> fuel in a "big dumb booster", and if so, how would its use 
> compare ECONOMICALLY to more advanced fuels?
> 
> Or is this just a big dumb idea? ;-}
> 
> Best, Jeff Davis

Jeff, good to see you back again.

They are doing this already.  The JATO rocket you described doesn't oxidize
the tar directly, but rather uses the tar to hold both the fuel and oxidizer
in a solid matrix.  When they combine, the solid matrix is melted and
vaporized, and out the nozzle it goes.  There is nothing magic about tar;
all it does is hold everything in place.  From a chemical reaction point of
view, we could use asphalt (long hydrocarbon chains) or parafin (long
hydrocarbon chains) or anything that is pretty much chemically equivalent,
which will all end up as CO2 and H20 coming out the tail end irregardful.

The solid rocket boosters on the shuttle and military rockets use a rubbery
compound to hold the fuel and oxidizer.  The material is chemically close to
asphalt, which isn't all that different from heavy weight motor oil, only
still longer carbon chains, more cross-linked by sulfur.

Big dumb booster is an idea which has been studied all to hell and gone.  A
good example was the Lockheed Launch Vehicle, which succeeded on its second
flight but was an economic failure.  It used four solid stages to orbit, the
stages being excessed military hardware bought cheap.

Interesting aside: in 1992, George HW Bush made a deal which freed up a lot
of military solid rocket boosters (formerly used for Trident
submarine-launched nukes) and some re-entry bodies.  Lockheed Launch Vehicle
used those boosters to get a small payload to orbit.  Recently this latest
guy, after W, can't think of his name, made a deal that again frees up a
bunch of military hardware, which is now available to rocket scientists to
think of other uses.  I understand there are a bunch of re-entry bodies
formerly being used to carry nukes, which are now coming available.  Back in
1994, I worked in a group that was doing exactly that: trying to find uses
for retired military re-entry bodies.  Now it is back to the future.  They
are using them as kinetic energy weapons, which is the only feasible use we
could find for them 16 yrs ago.

Have you any ideas?  Present them to DARPA forthwith, me lad!

spike