Salvage 1 was a TV series launched by a pilot TV movie (Salvage) in 1979. I watched the show during its original broadcast, enjoying the escapist fun, but quite cognizant that it was pure fantasy.
Premise of the show
Harry Broderick (Andy Griffith) is a man running a salvage business who has a talent for economically exploiting what others might see as junk. He sees an opportunity in recovering hardware NASA left on the Moon during the Apollo program, and recruits a fuel expert and a former astronaut to help him build a rocket ship to retrieve it.
The fuel expert has a "magic" formula for something many times more powerful than has been used in any rocket. IIRC, in-show it was dismissed by NASA as too unstable.
The former astronaut has a pet theory for a sort of shortcut route to the Moon which NASA dismissed as "crank" science.
The combination of the magic fuel and shortcut route make feasible a rocket built on a shoestring budget that can execute a salvage of things NASA left behind on the Moon.
Rocket Fuel
The Salvage 1 rocket fuel is pure Hollywood fiction. The John D. Clark book "Ignition!" presents an account of humanity's quest for the "best" possible rocket fuel ("best" depends on the qualities chosen to be of highest priority). The book lays out the numerous avenues of research and development and the corresponding outcomes. Based on the wisdom revealed in this book, no such fuel as depicted in the show could exist. There are limits to the amount/density of energy which can be stored chemically. The fuels which approach those theoretical limits are extremely difficult to handle - highly toxic (reactants and reaction products) and corrosive and/or unstable - basically expensive and dangerous to make and handle. Safer fuels (as commonly used) have less performance, but the difference is not "order of magnitude" as suggested by the show. A "super" fuel as depicted in the show simply could not exist, and anything approaching it could not be produced or handled on a shoestring budget.
Shortcut to the Moon
The "shortcut" to the Moon demonstrates a lack of understanding by the show's writing staff of high school-level physics. The premise in the show is that going into orbit first is a costly and unnecessary exercise which can be avoided by taking a straight-line path. From a common-sense perspective, you might think this is true. However, the laws of physics show that the lowest cost approach is (more-or-less) to loft yourself above the atmosphere (well, most of it), then accelerate to orbital velocity so you don't fall back to Earth, and finally accelerate some more to get onto a transfer trajectory toward your destination. In actuality, these steps are somewhat blended together, but the key point is that, for an energy-efficient rocket-propelled flight, you can't get away from a mad dash to at least orbital velocity at some phase in the flight.
Summary
The show threw in a few tidbits of "real science", but for the most part, sidestepped real physics and all sorts of problems which have to be solved to put a payload into space and deal with the space environment (zero gravity, no atmosphere, solar/cosmic radiation). This applies to both people and equipment. The show also distorted scale in all sorts of things, including the distance to the Moon and time required to traverse it, height of the atmosphere and (again) time required to safely travel between Earth's surface and a space environment.
The Apollo program was expensive, but it sought the "cheapest" possible route to the Moon in that the trajectory required the least (or thereabouts) amount of propellant possible at each phase. It also selected the most optimal propellant for each task.
- Getting what turned out to be a truly massive rocket off the ground took an enormous amount of thrust; RP-1 (refined kerosene) and liquid oxygen turn out to be the best choice in this role for a chemical rocket (as used in the Saturn V first stage).
- Getting up to orbital/transfer trajectory speed calls for high specific impulse - for a chemical rocket, this means liquid hydrogen and liquid oxygen (the Saturn V second and third stages).
- After a few days in space (the coast to lunar orbit), storability becomes a significant consideration, and because the crew is now beyond practical rescue, reliability is also a major concern, so hypergolic propellants are used, despite the lower specific impulse (Apollo CSM and LM).
What made Apollo expensive was partly that space is hard, and partly that the Kennedy mandate to go to the Moon had an aggressive timeframe attached to it. SpaceX is showing that access to space can be done less expensively, but you can only take things so far.
Just a few of the things that make rocketry and space travel expensive:
- Weight is critical, and everything adds up. Parts and materials need to be kept light while still being strong enough to do the required job.
- There is little or no room for defects. Shaving off weight means you leave little room for materials to be below spec. - everything has to be of high quality lest something important break and ruin your day. And generally, since you have to keep weight down, you only have what you need, so nothing is unimportant.
- Materials used in engine parts - combustion chambers, fuel pump turbine blades, and such have to withstand high temperatures and stresses simultaneously, and have to be made to fine tolerances. The materials and manufacturing processes to achieve that don't come cheap.
- Systems have to work in zero gravity. Dealing with the way fluids move in the absence of gravity can be a real trick.
- Systems have to work in a vacuum. In the absence of air, moving parts can vacuum weld together. Bearings etc. have to be designed and manufactured to work in a vacuum.
- You have to bring everything you're going to need with you. That can make for a long list, large quantities of supplies like air and water, and run up the mass budget.
Yes, you can make a cheap rocket, but a cheap rocket won't get you to space. To get to "cheap" you have to sacrifice important things. It may be too fragile and break; it may be too heavy and not take you very far; it may not carry enough propellant and again not take you very far; it may be too inefficient (low ISP) and not get you going fast enough; things may not work when needed because they weren't properly designed or tested for the environment they are in when called upon.
