The December 2015 edition of Scientific American contains a plug for a new/old idea called Microwave Rocketry. They date the idea to 1924 (the "old" part) but see it is a possible "World Changing Idea" (the "new" part). If you have never heard of this before, don't worry that you have somehow missed something. Nobody has figured out how to make it actually work yet. And the story didn't suggest that success was imminent.
But why would somebody want it to work? Because the current methods of transporting things into space don't work very well. I'll get to why later. Instead I am going to review the history of rockets (the current method that doesn't work very well). And, to make the subject more fun, I am going to look at rockets in the Science Fiction world as well as in the real world. Where to start? At the beginning, of course.
In round numbers the Chinese invented gunpowder, also called black powder, about a thousand years ago. Shortly thereafter they invented what we now call the skyrocket. A skyrocket is a firework. It's an entertainment device. But The Chinese quickly tried to repurpose it as a military weapon. It turns out that "shock and awe" is a thousand year old idea. When one side shot off a bunch of rockets at the other side for the first time they were shocked and awed. But that didn't last very long. The other side quickly figured out that rockets were so inaccurate they did not pose a serious threat to life and limb. So they quickly started ignoring them. The shock and awe thing didn't last very long.
And, in spite of the lack of success on the part of the Chinese, the very same tactic was tried over and over in the intervening centuries. During the Napoleonic Wars (roughly 1800) fusillades of rockets were shot off. The results were the same. A short period of shock and awe was quickly followed by indifference. The Soviets tried the same thing during World War II. They had a device called a Stalin Organ. It consisted of a trailer containing banks of rockets. All the rockets were shot off within a matter of a few seconds. At first the Germans were shocked and awed. But then they noticed that rockets were still wildly inaccurate and ignored them. That's the real world. Let's detour into the world of fiction.
Joules Verne was the first modern Science Fiction writer. He was very familiar with the science and technology of the time. Starting in 1863 he extrapolated from what he knew to form the technological base of a series of adventure novels. One of his first was called (in English, Verne wrote in French) "From the Earth to the Moon". The basic story was about a group of intrepid adventurers traveling from the Earth to the Moon and back again. If such a tale was being written now the method of transportation would have been a rocket ship. But Verne distained that method and instead went with a giant cannon.
Any technologist of his time would have made the same choice. There was a lot of scientific understanding of how to create large artillery pieces (fancy talk for cannons) and what they were capable of. The state of the art had advanced to the point where it was conceivable that a slightly more advanced design would be capable of hitting the moon with a large shell. There were a lot of other problems, dealing with the acceleration, navigation, slowing down when you got to the moon, etc. But in terms of picking the basic technology Vern made the right choice. There was literally no such thing as Rocket Science in the late 1800's.
Verne's scientifically credible style fell out of favor. About 50 years after Verne started writing Edgar Rice Burroughs, the guy who invented Tarzan of the Apes, also invented John Carter of Mars. (Do NOT see the movie of a few years ago. It's terrible!) Burroughs used completely fantastical methods to get Carter back and forth between Earth and Mars. And, for the most part, so did a lot of authors as the new literary style called Science Fiction came into existence in roughly 1920. Science Fiction largely was organized around the fantasies of young males. So it featured a lot of babes, monsters, and ray guns. But this gradually changed. The prime mover behind this change was an editor named John W. Campbell.
Campbell championed the idea of making Science Fiction science based. Sticking purely to what was scientifically known and understood was no fun. So Campbell gave his authors one out. They were allowed to violate one law of science as it was known and understood. This rule was not rigidly adhered to. But it pushed Science Fiction in the direction of being much more science based. The result is what fans now call the first golden age of Science Fiction. So it was ultimately every effective.
There was still no actual rocket science in the early phases of this period. But that soon changed dramatically. And the dramatic change can be attributed to a single individual. His name is Robert H. Goddard. Goddard is now mostly lost to the annals of history. He is memorialized in the name of the Goddard Space Flight Center in Greenbelt, Maryland. But this is a NASA facility and who pays attention to NASA these days? This piece is actually a shout out to Goddard. He operated with a shoe string budget his entire life. He literally invented Rocket Science and yet he was pretty much unsung during his fruitful years and is pretty much unknown now. So who was Goddard and what did he do?
He was born in 1882 and got most of his academic training at a small Massachusetts school called Clark College. He did his research between about 1915 and about 1940. From the beginning until about 1930 he mostly worked at Clark where was a professor. For the first decade he funded his research solely out of his modest salary. In the '20s he got some foundation money and continued his research, still operating out of Clark. In the '30s he got a bigger chunk of money from the Guggenheim foundation. This allowed him to move to Roswell New Mexico where he could conduct bigger and messier experiments without blowing up his neighbors.. His New Mexico work continued until 1941. He died in 1945.
So what did he come up with? The answer is pretty much everything. As I indicated above, before Goddard rockets were pretty much fireworks. The military experimented with them but what they used was pretty much skyrockets on steroids. The design, construction, and effectiveness was skyrocket-quality. Goddard changed all this. His first inquiry was into the rocket part.
Rockets are your classical Newtonian device. Newton said "for every action there is an equal and opposite reaction". You make a rocket go by throwing things out the back. That's the "action". The result is that the rocket speeds away in the opposite direction. That's the "reaction". And the "equal and opposite part" tells you exactly how much reaction you will get for a given amount of action. Throw it twice as fast and the rocket speeds up twice as much. Throw something that is twice as heavy and the rocket speeds up twice as much. It's really as simple as that.
So Goddard first focused on throwing things out the back faster. He designed a nozzle to put on the rocket that meant the gasses flying out the back ended up going a lot faster. This seems obvious but Goddard was the first person to actually take a hard look at what was going on and try to improve things. Another now obvious question Goddard was the first to investigate was "do rockets work in a vacuum?" They do but no one had even thought to ask the question. Goddard asked the question and designed and executed experiments to provide the answer. Goddard then designed and built the first working Ion Drive. More about that below. During this period Goddard was able to procure a massive (just kidding) grant totaling $5,000. Even in those days this was not a lot of money.
Goddard went on to investigate other aspects of Rocket Science. One was getting rockets to go where you wanted them to. He figured out that if he used a design that put most of the weight toward the bottom the rocket would naturally want to fly straight up. He also investigated fins and gyrocompass systems for accurately guiding the rocket in the path you wanted it to follow.
There's another trick to throwing the fuel out the back faster. That's what fuel you use. Goddard investigated various classes (solid, liquid) and types of fuels (chemical composition). When you burn a fuel it generates a specific amount of heat per pound. Chemists know exactly how much heat burning any specific combination of chemicals will generate. This leads to a shorthand trick for figuring out what makes the best fuel. The hotter it burns the better.
If this combination burns hotter than that combination and you can figure out how to keep the rocket motor from burning up then the hotter burning fuel can be made to go out the back faster. It gives you more thrust per pound. Goddard investigated a bunch of fuel combinations and ended up with recommendations that are still used to this day. Hydrogen and Oxygen are one of the best combinations. Kerosene and Oxygen work almost as well. Black powder, the classic rocket fuel, is actually pretty terrible. If you want to go with solid fuel then there are lots of combinations that work much better than black powder but none of them work quite as well as the best liquid combinations.
A rocket essentially consists of two things: the fuel and everything else. It is obviously a good idea to keep the "everything else" part to a minimum. All of it has to be hauled around and none of it makes the rocket go faster. In fact, the more the "everything else" weighs the slower the rocket goes. So Goddard investigated ideas in this area too. And he came up with the multistage rocket. If you have one device then it has to have big engines (heavy) and a big structure to hold all that fuel (more weight). But what if you have a big stage on the bottom? This would have big engines and big fuel tanks. But let's say you stack a much smaller stage on top of it? This can be much lighter because it can have smaller engines and fuel tanks. And so on.
Goddard came up with some stage designs, built them, and tested them. He found he could improve overall efficiency by a few percent. He even figured out where the point of diminishing returns was. If you have a dozen stages then you end up with so much weight invested in all the various engines and fuel tanks then you are worse off than when you started. Depending on the details, 2-4 stages is optimum.
Goddard also did the calculations for how well the much improved rockets he was building could work. He was the first one to say that a rocket could be used to get to space and to have the science with which to back this statement up. For his trouble the New York Times castigated him as some kind of kook in an editorial. And so it went. People with no technical background or who failed to investigate his work carefully wrote him off as a crackpot. This made it hard for him to be taken seriously. It also made it particularly hard for him to raise money. During his best times he was operating on a $100,000 Guggenheim grant. But that had to last 4 years and cover all of his costs. He never was accorded much respect during his lifetime. Well, not in the US.
There was one group of people who respected his work tremendously. That was Werner von Braun and the group of Nazi rocket scientists he assembled. They extended and enhanced his work to develop the V-2 rocket. The V-2 was the first rocket to be used successful as a military weapon. It wrecked a lot of devastation on England and its design became the foundation of all subsequent rocket programs around the world. In the immediate aftermath of World War II there was a rush by both the US and the USSR (as Russia was called at the time) to scoop up what they could of the Nazi rocket program. Roughly speaking the USSR got the bulk of the equipment and the US got the bulk of the people. The V-2 finally convinced everyone that rockets could be for real.
Now back to fiction. Science Fiction quickly abandoned cannons and went with rockets at about the time Campbell started to become influential. I don't know if it was his influence or for some other reason. At that time the specifications of these early fictional rockets were literally fantastic. This can best be illustrated by considering a couple of famous movie serials that were hugely popular in the '30s. One featured Buck Rogers and the other featured Flash Gordon.
They both used the same crude special effects that were the best available at the time. The result was rockets that behaved more like airplanes. They took off and landed on their bellies and flew all over the place without refueling. And on one was killed by the rocket exhaust. When it came to rocket exhaust, pretty much the same was true of print fiction of the period. But all of this can be excused because, with the exception of Goddard's work, actual scientists didn't know what the rules were either.
The V-2 changed all that. After the War fictional rockets started taking off and landing on their tails. Generally some effort was made to safely handle the rocket exhaust. Rockets still had infinite quantities of fuel. But guns in the fiction of the time also had infinite quantities of bullets so it is hard to get mad at the people creating rocket shows. The shape of the rocket also went from being non-specific to being V-2-like.
The V-2 shape was based on the shape of high speed bullets. The V-2 had a sharp point. The tail of the V-2 nipped in unlike a bullet but that was a result of the design of the rocket engine. And fictional rockets of the period emulated that design feature too. The V-2 had control fins at the bottom so fictional rockets also had them. In short, the fictional world of the rocket quickly adapted to more closely match reality now that there was a real world model to copy. Interestingly enough, the Hugo Award, one of the major science fiction awards to this day still closely matches the shape of a slightly sexed up V-2.
Returning to the real world, science marched on fairly quickly after the War using the V-2 design as the foundation. Goddard's work was quickly resurrected and celebrated in this period but by this time he was dead. An obvious thought had occurred to pretty much everyone. If a V-2 can be used to carry an explosive charge from Europe to London can a super-V-2 be used to carry an Atomic bomb from one side of the world to the other? The answer looked like it was at least "possibly". That was close enough to "yes" to spur the military in several countries to immediately become very interested in rocket design. And that meant that the lean Goddard days were over when it came to funding for rocket research.
And it turned out that bomb design influenced rocket design in an unexpected way. The US invented the atomic bomb and was quickly able to move on to small, light, designs. The USSR was not as able to come up with small light designs nearly so quickly. So they decided that it was important to develop big rockets that could handle their heavier bombs. So they were able to build big rockets much sooner than the US. And this resulted in the Russians being the first to launch the first artificial satellite and to put the first man in space. They were able to use this early "throw weight" advantage to rack up many firsts early in the space race. One of the ideas that went into Kennedy's "go to the moon" speech was the knowledge that it would take several years for the US to match the Russians in heavy rockets. The moon shot was picked because it was ten years out. And ten years was long enough for the US to catch up in throw weight.
The period from about 1955 to about 1975 was the golden age for both factual rocketry and fictional rocketry. Both were making rapid advances. We went from being barely being able to put a beach ball sized satellite into low earth orbit (about 100-250 miles up) to putting a man on the moon (250,000 miles away). And there were enough unknowns that the fiction writers had scope enough to write lots of fun and exciting stories that didn't stray too far from the science. And, most obviously, by now there actually was such a thing as Rocket Science. So both did very well. But then a strange thing happened. It all kind of petered out. Why?
My theory is that Goddard actually did too thorough a job. He was too cash constrained to take rockets to their logical limits. But he did an amazing job of mapping out where those logical limits were. Nobody has built a 12 stage rocket. Nobody has come up with an amazing fuel that works much better than any of the ones Goddard investigated. It turns out that there are rules for how good you can make a rocket. One of them is what I call the 90-9-1 rule.
I'm now going to subdivide "other stuff" into "structure" (the boring stuff - rocket engines, tanks, stuff like that) and "payload" (the interesting stuff - people, scientific instruments, stuff like that). A modern rocket consists of 90% fuel, 9% structure, and 1% payload. You can fudge numbers a little with improved designs and materials but you can't fudge them by much.
The Saturn 5 that took men to the moon in 1970 pretty much followed this rule. The Space Shuttle that followed it and was the workhorse of the US space program for several decades pretty much followed this rule. We now have the latest and greatest "privately funded" rocket designs done by people like those at Elon Musk's Space-X. But as far as I can tell the Space-X designs (and those of their competitors) hew very closely to this 90-9-1 rule. If you think NASA is a bureaucratic mess then Musk and his ilk can drive some of the cost out of the system by running a lean and mean operation. But it still looks like if one of these new companies wants to put 1 pound of something into low earth orbit they are going to need to buy about 90 pounds of fuel.
You are going to also have some other expenses (those have probably gone up) but fuel costs haven't changed a lot since the Apollo program. The Falcon 9 (Musk's rocket) uses pretty much the same fuel as the Saturn 5 did. And fuel costs pretty much the same per pound (adjusting for inflation) as it did back then. So the fundamentals haven't changed much in the last 40 or so years. And that means getting to space will always be very expensive.
This stagnation over the past 40 years has been bad for space exploration, or at least manned (or womanned - they are actually a better choice because they tend to be lighter) space exploration. It has also been bad for Science Fiction. Hewing to a stagnant science resulted in telling the same stories over and over. Science Fiction has reacted to this problem by splitting and going down two paths. Down one path you have the traditional space epic. In terms of popularity they are now more popular than ever in the movies and on TV. These tend to have a superficial scientific gloss. But if you look at the propulsion systems, for instance, it's all hand-wavium. You have people briefly waving their hands around and using scientific sounding terms like "warp drive" and "dilithium" and then quickly pivoting away to the exciting stuff.
Fictional space ships are either powered by rockets of unspecified design or use some entirely different method of propulsion. And in many cases the story is standard "wagon train to the stars" where the Science Fiction elements are there mostly to spice things up. This approach has been very popular in visual mediums but has been mostly abandoned in print.
The other trend is to abandon science entirely and go back to fantasy. I read a lot of modern fantasy. In terms of quality it is head and shoulders above the likes of Burroughs' John Carter. Some fantasy is recognizable as Science Fiction but the most fantasy is now vaguely medieval "Swords and Sorcery" stuff. The most obvious example of this is the "Game of Thrones" (TV show title - the books go by "A Song of Ice and Fire") series by George R. R. Martin. There are literally dozens of other examples. The Martin series is the most popular at the moment but a number of the others have large loyal followings.
So why has Science Fiction abandoned science based rocket design for space travel? In my opinion it is because none of the scientific fundamentals of rocket design have changed in several decades. Well, you might ask, what about going with future stuff or fictional stuff, things like the Microwave Rocket I mentioned at the top of this piece? The problem the Microwave Rocket is supposed to solve is the 90-9-1 problem. And, if you could get it to work, it would solve the problem, at least in terms of getting something into low earth orbit. But nobody has figured out how to make it work in the last 90 years. And I don't think anybody will get it to work any time soon.
Let me give you another example of a way to avoid the 90-9-1 problem (again just for trips to low earth orbit). It is called the Space Elevator. The idea was popularized by a book called "The Fountains of Paradise". It was written by Arthur C. Clark, a noted Science Fiction author, and published in 1978. Everybody loves the idea but no one has figured out how to build it. People have dreamed up a lot of ideas in the last 40 years, or the last 90 years, if you count from the introduction of the idea of the Microwave Rocket. Its just that nobody has been able to get any of them to work. So is there nothing out there?
Well, there is the Ion drive. The benefit of the Ion drive is that it throws things out the back at extremely high speed. The speed is way higher than the fastest possible speed a rocket design based on chemical reactions can achieve. This means you get a whole lot more push per pound of fuel. And a number of Ion drive rocket motors have been built and successfully put into operation. But frankly we only know how to make small low power Ion drives. And they only work in the vacuum of space. So they only look like a fit for a few selected deep space missions. Anything else? Surely Science Fiction writers or somebody has come up with something else. Funny you should ask?
There is a web site for that. Here's the link: http://www.projectrho.com/public_html/rocket/index.php. It was created by a guy who does illustrations for fantasy works, a guy named Winchell Chung. He set out to do the math (or find someone who had already done the math) on pretty much every aspect of rocket ships. So the results from all the calculations behind standard "real world" stuff are posted here in user friendly form (frequently as an easy to use graph). But then there are also results posted concerning pretty crazy but maybe possible ideas like a rocket powered by atomic bomb explosions. But he goes even farther. He has analyzed how well the various types of fantastical space drives would work. He has even explored ancillary topics like ray guns, space suits, lasers, phasers, you name it.
This site has now been around for some time and it hasn't changed much in recent years. Why? Because people have not been able to come up with any really new ideas in a while. And Chung's site tells you how well various real, slightly fictional, and totally way out there technologies would actually work. Unfortunately, mostly the answer is not nearly as well as they do in the books and movies. And that's after he assumes that what some author has made up actually works generally the way the author says it would. Usually it wouldn't and the web site tells you why.
This doesn't stop me from enjoying myself anyhow when it comes to my entertainment habits. I'm pretty good at ignoring reality if its entertaining enough. I hope this post doesn't get in the way of you enjoying the best in contemporary entertainment either. There are times when a willing suspension of disbelief is the right and true thing to do.
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