I knew the half century anniversary of the Apollo 17 splashdown was coming but it was depressing, and I ignored it. However, it seems a good opportunity to summarize much of what I have been thinking about over the last decade or so, and also to finish with my concept art of a “true” Spaceship with a massive cosmic ray shield, tether generated artificial gravity, and Nuclear Pulse Propulsion. Space was interesting to me when I was a boy, just as it was for most young people in the 60’s, and this was mainly due to science fiction movies of course. I did receive a boxed paperback set of the Lensman series one Christmas as the 70’s began and so perhaps I did have more than the usual fascination instilled early on. I was not a sports fan and maybe should have become a sci-fi nerd but the influence of a friend and my family’s military tradition pointed me more at World War Two and I became a war nerd instead. That conflict and the following cold war did eventually point me at space in a peculiar way. My wife needed help with a class in situational ethics and asked me for suggestions and I told her nuclear weapons might be related and provide material for a paper. So, she sent me to the library to find books and I happened upon, “Project Orion, the true story of the atomic spaceship”, and I was hooked. Almost twenty years later I am still a space enthusiast and sketching spaceship concepts.
Sadly, space has not worked well as a hobby for me because of a certain “entrepreneur” and his gang of cyberthugs. It is lonely existing outside of Elonverse, with all those toxic creeps vigilant and on patrol at the gates to the spaceport. But I am not so discouraged that I do not continue to follow the one true prophet of space colonization, and I still have hopes of an O’Neillian future for humankind. Space Solar Power by way of lunar resources remains the ultimate solution to climate change and one fine day that may become apparent to the rest of the world.
Then….I will be vindicated!
Vertical Take-off Vertical Landing (VTVL) rockets were not invented by Elon Musk and were envisioned from the very start with the movie Frau im Mond depicting it in 1929, only a few years after Goddard tested the first liquid fuel rocket. I would speculate one thing that might have changed the entire course of the space age would have been NASA announcing the massive Saturn V first stage would be vertically landed back onto a ship at sea by remote control- and the Apollo capsule and escape tower would also be reused, “as soon as practical”. A V-2 rocket had been launched off the deck of an aircraft carrier in 1947 and rockets landing back vertically became a common theme on 1950’s television shows. Engineer Phil Bono began to submit concepts for VTVL in the early sixties and his dream was finally realized shortly after his death with the vertical take-off and landing of the Delta Clipper rocket in 1993. Elon Musk was not involved.
The logical progression that should have been followed during the last century of space exploration is in hindsight very clear. How this starry program was derailed is very unclear and complicated. That a scientist with degrees in physics like Robert Goddard writing about rockets was denigrated and humiliated by the press seems strange after a pair of bicycle salesmen with high school diplomas had already built the first airplane. That America built such magnificent machines yet made the worst possible decisions about their design and use follows that strangeness. The failure to explain how rockets work to the public may have been the most significant factor leading to the end of the space age. The taxpayer watched fantastically expensive and giant pieces of hardware disappear into the sky and only a very small capsule return and, to add insult to injury, even the tiny capsule was not reusable. It might have helped to explain that all conveyances, including ships, aircraft, and vehicles, after traveling so many miles are eventually scrapped. Spacecraft traveling millions of miles at thousands of miles an hour by using up and scrapping all the mass necessary to do that in the first few minute’s sounds reasonable- but for those paying taxes the question of why that super-expensive mass was being used up would still have remained.
Project Orion could have been the best way to initially explain space travel to the public but was never publicized in that way. Several years before Yuri Gagarin’s flight, Nuclear Pulse Propulsion was a practical technology available to be developed and carry large numbers of humans to the outer planets on epic voyages of discovery. There were no real technical obstacles to Nuclear Pulse Propulsion in the late 1950’s. The genius Stanislaw Ulam, who originated the concept and also invented the hydrogen bomb after the first atomic bombs, considered it his greatest work. The problem, of course, was and is the use of repurposed nuclear weapons. Setting aside the political issue, which to this day means the possibility of using them even outside the Earth’s magnetosphere with no fallout is not entertained, the contamination from a ground launch is completely unacceptable. Which means for now only multi-stage chemical rockets, literally a million times less powerful than a nuclear pulse propelled spaceship, is what we must use to lift humans off the surface of the Earth into space.
Explaining rocket staging to the layman can be difficult, much like difficulties I experienced explaining how a paraglider works to people who would watch me kiting my wing on a beach. They would ask me if I was going to fly and I would tell them gliders, when you see them maintaining altitude or climbing, are actually always flying downward through the air. The air around them is just going up faster than they are going down. A kind of optical illusion. I was practicing how to take-off, but the air has to be going up for me to fly and on the beach it was just coming straight at me. Like a car sitting on level ground instead of rolling downhill, I could not go anywhere. Then they would realize why I could not take-off from the beach. I have read the rocket pioneer Robert H. Goddard felt deeply humiliated by articles ridiculing him, but he might have tried to explain it to the newspapers better. Who knows what support he might have received then?
The best explanation I have read is to imagine standing on a child’s four-wheel wagon. You can wave your arms and it might move an inch or so back and forth, but you will not go anywhere. This was the common late 19th century conception of space as a vacuum, where there was nothing to push against so you could not go anywhere. To these journalists without a basic understanding of physics, Goddard’s spaceship was the ridiculous idea of a crank. But if you have a small stack of bricks in the wagon, and you pick one up and throw it, the wagon will actually move a short distance. This is how a rocket works and why Goddard, a physicist, knew it would work while those calling him a fool were actually the ignorant ones. Journalism is not rocket science.
Staging is about the rocket equation, written specifically for space travel by a Russian self-taught and deaf peasant librarian named Tsiolkovsky. He calculated two different escape velocities, one to achieve orbital flight and a faster one to completely leave Earth behind. From Newton’s equations in 1687 the idea had long been entertained you could shoot a cannon ball fast enough and at the right angle so it would no longer arc back to Earth but just keep falling around the planet. Tsiolkovsky wrote his equation in 1903, the same year the Wright brothers flew the first airplane, and it mathematically and precisely explained spaceflight and also calculated the velocity needed to leave Earth forever.
The rocket equation essentially means chemical energy is simply not powerful enough to get us into space on one big rocket. Lifting the heavy mass of engines and propellants and the structure carrying them uses up all those propellants before you get high and fast enough to reach escape velocity. If the bulky mass of the large tank structure and attached heavy engines could somehow progressively shrink and become lighter as propellants were used up, then the rocket could then achieve escape velocity before running out of propellants. And the way to do this is…stack a smaller lighter rocket with smaller lighter engines on top of the big rocket and just separate from the big one and leave all that dead weight behind when it is empty. Because of the low energy of chemical propellants, the drag of the lower atmosphere, and the depth of Earth’s gravity well, typically one rocket, the first stage, must loft and launch another smaller rocket, the second stage, which carries yet a third rocket. This final fractional payload of useful mass then goes high enough and fast enough to keep falling around the planet. Or leave and go to other planets.
Staging was how to get vehicles into space, but it was incredibly inefficient compared to other familiar conveyances and returning the stages back to Earth for reuse was not considered since this added a great deal of mass when reducing it by even a few pounds was critical and was the whole point. Not until advances in engines and materials made it seem just barely practical. Only now, in 2022, are rocket first stages being reused 10 to 15 times, which is considered the bare minimum for “breaking even” and replacing expendable stages. And it is still not proven that the company doing this is saving any money compared to expendable rockets. This is much like starting out with throw-away plastic jugs and then going to glass bottles that are picked up by the milkman and reused. The second stage of this model of rocket is still expended with it’s engine and it bears mentioning the Space Shuttle, while it never came close to breaking even, only expended a tank and returned all it’s expensive engines back to Earth for reuse. While it is just a matter of profit margins for the satellite industry, expendable versus reusable rockets for the citizen who is paying for Human Space Fight is the single greatest perceived issue regarding supporting and being willing to spend tax dollars on space exploration.
On the list of worst possible decisions made concerning space exploration, the number one bad call, in my view, was cancelling the Saturn V. As stated earlier, NASA could have made improving Saturn V with different iterations over a decades long program a fundamental goal of the space agency. Instead of the Shuttle, the first iteration S1C would likely have been a vertically landing back first stage. This was first done in 1993 with the Delta Clipper rocket, exactly 20 years after the last Saturn V launch and 12 years after the first Shuttle launch. In fact, using directed thrust for vertical takeoff and landing became an operational military reality in 1967 with the first flight of the Harrier Jump Jet. In terms of concept and engineering difficulty there is, in reality, not that much of a difference between a Jump Jet hovering and landing vertically and the first stage of a rocket hovering and landing vertically. Instead of the Shuttle being the pickup truck of space it would have been the Saturn V, with the first stage, made by Boeing, landing back for reuse as the first step in a fully reusable system. If, for example, the 1967 Harrier was taken as inspiration for landing back the S1C first stage and development had begun then, it is no stretch of the imagination to expect S1C landing back operations to have commenced by 1980, instead of the Shuttle.
Making a reusable Saturn V first stage, despite it’s size, would not have been as difficult as reusing the second stage. After reusing the first stage, capsule, and escape tower, the next step would have been returning the second stage and landing it for reuse. The second stage would have done at least one orbit, reentered and returned to vertically land at the launch site. We can see the very similar size and shape of the Shuttle external tank and the 21st century shiny starship prototype. The replacement for the North American S-ll second stage would have been a external tank sized stage with heat shield tiles and much smaller wing surfaces like the shiny stacked on top of the S1C.
This most likely design for a reusable second stage would have been a kind of fat uncrewed shuttle stacked on top of the already VTVL Boeing S1C, and landing back as a VTVL second stage in the early 1990’s. And on top of this stack, we can speculate as a standard payload the prime innovation that never should have been abandoned. Not using propellant tankage as payload was by my count the 2nd worst mistake NASA ever made. The wet workshop, the ultimate reusability scheme, has been unjustly condemned as a failed concept over the years, despite Skylab orbiting a space station in one afternoon when it took more than 30 missions over a decade to assemble the ISS. If von Braun had been given the extra few million dollars he requested to make Skylab a full wet workshop instead of a less expensive dry workshop, it would have been larger than the ISS with one launch.
The mass penalties for making the first and second stages of the Saturn V reusable would have been large and these iterations would have grown in size proportionally to that added mass. Lighter materials and more efficient engines would compensate somewhat but an early 21st century iteration of the Saturn V would be more like the Nova rocket originally specified for Apollo. Not a good design path to increase the number of engines though, so keeping five thrust bells for the first and second stages would be desirable. This follows the K.I.S.S. philosophy abandoned by everyone’s favorite rocket company. The Russian RD-180 is a good model to follow as it uses a single set of turbopumps to feed two thrust bells. A full-flow hydrogen rocket engine with each bell producing between 2 and 3 million pounds of thrust seems optimum in my view. The central engine would be the landing engine and thus, a pair of these engines, each with two thrust bells, and a less powerful landing engine is the most likely first stage configuration. The second stage would probably have a powerful central engine and use four smaller outer steering engines for landing.
A year before the Nazi’s launched the first rocket into space, the first operational jet aircraft took to the air in 1941. It is interesting to note the configuration of the ME-262 is exactly the same used today in all jet airliners.
The Russian Soyuz rocket family, first flown in 1957 over sixty years ago, also uses the same hydrogen peroxide turbopump system used in the first successful V2 rocket launch in 1942. The thrust chambers of the Soyuz generate a similar amount of energy to that first rocket launch over 80 years ago, when Nazi SS General Walter Dornberger announced, “This third day of October, 1942, is the first of a new era in transportation, that of space travel..” Dornberger later became vice president of Bell aircraft company.
Skylab may not be the best example to cite since retreating to Low Earth Orbit is by my count the 3rd worst mistake NASA ever made. The Moon was always the place to go, and the wet workshop would have been the critical building block of a cislunar infrastructure. Continuing exploration of the Moon with robot rovers and orbiting lunar satellites with radar and other sensors would have found the ice that was finally detected in 2008. Retreating to LEO insured that the ice, so absolutely necessary to expanding humankind into space, would be found 30 years late. The fact that cosmic radiation requires water shielding massing well over a thousand tons for a relatively small crew compartment means that lunar ice, lifted from the lunar surface using 20 times less energy than lifting water from Earth, is the single critical resource necessary for Human Space Flight Beyond Earth and Lunar Orbit (HSF-BELO).
The third stage wet workshop on top of that speculative late 20th century reusable Saturn V iteration would be built to accommodate a water shield and be double-hulled and spherical. A “Fat Workshop.” Connecting two wet workshop crew compartments with a tether system, or one to an equal mass, and thus providing a Near Sea Level Radiation 1 Gravity (NSLR1G) environment, would enable a permanent human presence Beyond Low Earth Orbit with no dosing or debilitation and thus no permanent damage to astronauts.
It may be that in some alternate universe the Saturn V program continued and Gerard K. O’Neill convinced the U.S. government in the 1970’s that Space Solar Power and not cold war toys were the economic future of America. In that other world a version of myself might actually now be employed in a factory on the Moon in 2022, instead of dreaming about it. In this dream are lunar manufactured 1000-foot diameter multi-thousand-ton alloy discs as Nuclear Pulse Propulsion “engines.” Miles in diameter artificial hollow spinning moons as the future home of the human race with Earth becoming a vacation destination. Beam propelled ships gradually transferring the human race to space. Whole body cryopreservation without damage and the first Bernal Sphere Starships leaving the solar system. I can dream.
My most recent musings have concerned the SLS and future iterations, but the best possible future is likely a clean sheet design and perhaps focusing on that ultimate reusability scheme I cited.
I have been thinking about getting that “Fat Workshop” into space and when the concept is carried to its logical conclusion it is the structure itself that is really the primary payload and so not losing any structure becomes the goal. This seems to largely defeat the whole purpose of staging though, and leaves only jettisoning the engines as a way to reduce mass and reach escape velocity. It may be possible to get by with just jettisoning engines, or it may take new engine developments, like rotating detonation, to make it happen. By attaching an outer and inner ring of engines, and single center Earth departure engine, the Chrysler SERV appears the best guide for effecting the Fat Workshop double-hull concept. The first U.S. orbital flight was accomplished on a “stage and half” vehicle, the Atlas, which only dropped the weight of two of three engines to attain orbit. This Atlas/SERV would have two rings of engines, the larger of which would land on a ship and the second would attain a low one-orbit return to launch. The last central engine would perform a Trans Lunar Injection burn, separate, perform a free return around the Moon to reenter and be reused. The central engine could certainly be heli-captured and it is even possible the smaller ring could be light enough to be heli-captured.
My speculative cislunar infrastructure would launch these SERV-like Super Heavy Lift Vehicles fifty times a year for the Moon. The first ones would not leave geostationary Earth orbit and send robot landers to the Moon. These semi-expendable landers would derive their own propellants from lunar ice and lift back into space to intercept later workshops transiting across the cislunar sea to the Moon, rendezvous, and insert them into lunar frozen orbits. The robots would then ferry water from the surface up to the workshops filling their cosmic ray shields. Eventually these NSLR1G crew compartments would provide Space Stations in cislunar space and geostationary Earth orbit as well as Lunar Cyclers providing transportation to and from the lunar Space Stations.