"shuttle"/BDB combo and fertilizer?

Hi all....

While Im sure this ISNT a new idea....I havent seen it discussed lately....so
here we go...


Did some web research awhile ago and found some pretty interesting stuff on
what are often referred to as "Big Dumb Boosters" (no, not those fat, old guys
at the university football games :)....

BDBs are basically low tech, low performance rockets....pressure feed
usually....and the proponents make a pretty good argument about just making
CHEAP but VERY large throw away rockets....and that using the construction
techniques more along the lines of modern ship building rather than clean room
research lab handbuilt rocketry could result in much cheaper total payload to
orbit costs...

Problem is...nobody seems interested in building/trying something 2 to 3 times
the size of a Saturn V with only a fraction of the payload ability....

Then, some recent reading of SSTO and TSO reusable spacecraft got me
thinking....

What if we take something like the shuttle, minus those damn wings and wheels,
and drop the performance requirements a bit.....often times you can get things
ALOT cheaper and more reliable if you can live with a modest performance
penalty....now you still would probably want an expendable shuttle like
"external" tank and perhaps even an expendable payload bay.....just keep the
crew compartment and the expensive main engines and associated stuff as the
resuable items...not sure how the geometry of such a thing would work
though....

Now that we've backed off the bleeding/leading edge of rocket
engineering.....we take the new "shuttle" design and put THAT on top of a BDB
first stage....make that expendable as well, but since it only has to make up
for (a WAG here) say a 10 to 30 percent drop in the top stage's
performance....the first stage main job is relaxed to mostly giving the top
stage a few kms per sec velocity and getting it up above most of the atmosphere
so the top stage can engines optimized for working in a vacuum...


Perhaps even "throw" a few solids on the side of the BDB first stage as a
zeroth  stage....

So now we have something more along the lines of a lower tech/cheaper? 2 stage
vs the shuttle high tech/expensive 1.5 stage....or even a 2.5 stage if we put
solids on the BDB first stage

Sure, your launch MASS will be a good bit higher....but shipyard level mass is
ALOT cheaper per pound than AEROSPACE mass....and dropping the perfomance
requirements a bit could at least in theory make the reuseable upper stage
cheaper to build/maintian and it might even increase reliability a bit...

Just some junk food for thought for your possible consumption....


Oh yeah...as a mostly  irrelevant aside.....about a year ago I had the idea of
dissolving ammonium nitrate in water and using that as a liquid oxidizer....you
can dissolve ALOT of fertilizer in water...particularly if you allow the water
to be a bit on the warm side......

I've lost my notes on it....but IFFF I did the calcs right the performance was
a lot better than youd think it would be offhand....IIRC the performance was
along the lines of a either a 50 percent h2o2 monopropellant rocket or maybe
even as high as a 50 percent h2o2/liquid fuel rocket....my memory fails me
there....

Sure, those  are pretty much useless unless you want WAY too many stages and
starting mass to get to orbit.....but it might be useful for an X prize level
rocket....

Dissolved fertilizer would be pretty darn stable I would think.....and has got
to be easier to get in large quantities than nitrous oxide or h2o2....

At least this would probably be the easiest of "oxidizers" to handle in the
rocketry world...

You might even be able to also put your fuel in the water as well.....one of
the alchohols maybe..... 

anybody feel like running the numbers themselves to see if I managed to not be
off by a factor of 10 somehow?

Anyhow....take care and happy holidays everyone!

Blll