Mockingbird

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A team of engineers at Lawrence Livermore National Laboratory proposed building a very small (ie pickup truck-size) single-stage reusable orbital launch vehicle in the mid-1990s. You can read more about that here:
Multiple Application Rocket Drone (MARD) Technical and Programmatic Overview

Some people seem to have obsessive personalities. Don Quixote insisted on fighting the imaginary beasts he saw in windmills. George Mallory was fixated on summiting Mount Everest. People kept watching Lost despite its tendency to sprout plotholes the way a damp field sprouts mushrooms. For me, the idea of low-cost access between Earth and low Earth orbit is one of the few things that seems worth such a level of obsession. It's physically possible with current technology and would revolutionize the way our civilization fits into the universe. The trick is just how to do it, and programs like Mockingbird tantalize the mind with the possibility of proving the concept of (relatively) cheap travel by rocket. Now if anyone would go fund this...

I'm not a spacecraft engineer by day, but I took some classes that are relevant back in school and used to work for one of the little startup space companies, so here are a few comments I have on glancing though the presentation:

-I get the argument for selecting hydrogen peroxide as an oxidizer, but high-concentration peroxide is so hard to get, expensive, and temperamental (it tends to set organic matter on fire when it drips, for example), that I doubt it's worth the trade to get a nontoxic, easily-igniting oxidizer. Better to go with liquid oxygen,which is cheap and high performance but cryogenic, or nitrous oxide, which is liquid at room temperature under pressure and has about the same specific impulse as peroxide. Good on the authors for not even talking about the traditional hypergolics like nitrogen tetroxide and the various flavor of hydrazine. They're liquid at room temperature and ignite on contact, but are so toxic and carcinogenic they belong nowhere near anything labelled "low-cost" or "green."

-The propellant-feed pump weighs more than the engine if I read the mass breakdown chart right. This won't do. Better to bite the bullet and pay someone a decent wage to make a custom turbopump for the job. It would be very light, and every gram counts on a single-stage vehicle.

-It's interesting that ascent heating is such a big issue for the vehicle. Granted, it's small, so drag and gravity losses will be high, but there must be some non-obvious physics going on to make an all-aluminum structure unacceptable for Mockingbird but just fine for the Space Shuttle external tank.

-Are the numbers on the thermal protection system weight even remotely believable? If so, the concept is feasible and exciting. If not it all falls apart and this is just words on paper. A robust, light thermal protection system is possibly the most important unsolved problem in making a low-cost reusable orbital launch vehicle, so I wish the authors had spent more time going into detail here.

File this under "Please revisit, decision makers."