http://www.astronautix.com/n/novamm1c.html
The average American never really accepted the idea of millions of tax dollars in hardware being used for a few minutes and then dropped in the ocean. Watching that 3000 ton 39 story high fire-spewing roaring spire disappear into the sky and only a tiny capsule barely large enough to carry 3 people come back a week or so later seemed an incredible waste. If that 3000 tons had been a ship that sailed around the world twenty times without refueling nobody would have complained. Which is how far Saturn V and Apollo traveled to and from the Moon. A rocket will put a satellite in orbit that will endlessly fly millions of miles around the Earth. That rocket is a fragile shell pushed by an engine that is essentially a constantly detonating high explosive directional bomb. It seems reasonable it would wear out fairly quickly even if it accomplishes millions of miles of travel in that first push. Still, getting people to see it that way has always been a major obstacle to space exploration.
The present day success of the NewSpace flagship company is an interesting and queer reversal of that prevailing public opinion that led to the end of the first space age. The reality is that landing back the first stage is the ultimate parlor trick that has paid off in P.R. far beyond what it actually accomplishes. It remains to be seen exactly how much money is being saved by reusing the first stage of their rocket. I suspect much larger vehicles than even the shiny starship are required to break even and it would be a big surprise to the public if the numbers were revealed. So much is spent on recovering, inspecting, and refurbishing the rocket for repeated flights that just dropping it in the ocean and using a new one each time might just be cheaper. How can this be that, in the words of former Shuttle Program Manager John Shannon, “reusability is a myth”?
Labor is always the biggest expense and the man-hours spent on “turning a rocket around” compared to spending that time/money just building a new one for a single use can end up being not that much different. The more flights the more wear and tear and the more maintenance and probability of failures. The more engines and plumbing, the greater the complexity and the higher the associated costs. The “standing army” of well-paid technicians required to turn a rocket around was one of the major criticisms of the Shuttle program made by NewSpace proponents- but this does not seem to apply to their flagship. Really. The cult of maniac fans are triggered by any notion of this but it is actually true.
From Quora: “How much does SpaceX save by reusing a Falcon rocket?”
Answer by Jim Cantrell, CEO and Founder of Vector Space Systems:
“If you go through the R&D costs of developing a reusable launch vehicle, the opportunity costs (in terms of fuel used for return and the lost revenue opportunity for more payload to orbit) of returning the launcher to the first stage, and the costs of refurbishment between flights, generally accepted practice shows that you have to re-use the booster or launch the vehicle 5–10 times before you make your money back if you account for all the costs. Many papers have been written on this topic and this is a well established ‘rule of thumb’. This doesn’t even account for the price reduction that many customers flying on a ‘used’ first stage will likely demand. Thus I am thinking that very few, if any, of the SpaceX Falcon 9 first stages are going to be re-used for more than 3 or so flights and that SpaceX will therefore not break even on the reusability portion of the equation.”
On 3 June 2020 a Falcon 9 was launched and landed for the 5th time. So Cantrell was wrong and maybe they did at least break even with one rocket. But probably not. In any case the payload is far below what can be considered useful for any kind of Human Space Flight (HSF) application.
This brings us back to the original problem of space travel being perceived as just too expensive. What it really comes down to in terms of profit and loss is all loss and zero profit- at least for HSF. Geostationary Earth Orbit (GEO) telecommunications satellites generate billions in revenues but other than that there is very little money to be made in the private space sector. The Apollo 1 fire and ensuing draconian NASA oversight proved to the aerospace industry that Human Space Flight Beyond Earth Orbit (HSF-BEO) was going to be hard money. Military pilots could be lost in various designs that were known to have safety problems without much said while astronauts were not expendable, even if their rockets were. The industry chose the easy money of cold war toys. Thus ended the space age and the Space Agency retreated to Low Earth Orbit (LEO) which had really stopped being space after being left far behind by Apollo 8 in 1968. That’s right, a couple hundred miles up is not really space. Try a couple orders of magnitude farther out as the appropriate edge of space (GEO at 22,236 miles).
After Apollo, astronauts no longer left Earth orbit and these missions would more accurately be called “orbital flight.” A decade of Shuttle missions then made clear not much could be accomplished in LEO and possible cargo versions of the Shuttle attracted more and more attention. These variants could loft Earth Departure Stages (EDS) into orbit and eventually capsules and landers would be sent to the Moon using Earth Orbit Rendezvous (EOR) techniques. Sidemount was not perfect but it could have served to return humans to the Moon until a much larger Nova class vehicle to be discussed here entered service.
After Apollo and Skylab NASA was desperate to continue Human Space Flight in any diluted form even if it meant satellites and humans sharing the same ride. The Space Shuttle was going to replace all expendable launch vehicles by sending up everything, satellites and astronauts, on a single multi-purpose machine that only expended a large fuel tank and reused everything else. It sounded like the answer to NASA’s P.R. problem but the program would finally end, in the opinion of many, a tragic failure. A rocket with no escape system for the human crew seems in hindsight to be an absurd proposition- but only after losing two crews made it undeniable. The Shuttle ended up costing about as much as the Saturn V per launch and so, ironically, we could have just kept going to the Moon for those 30 years for the same amount of money. Likewise, the International Space Station (ISS) was assembled at vast expense over many years when for want of a few million more dollars Skylab would have been a wet instead of smaller dry workshop and been larger than the ISS in a single launch (interior living space).
I mentioned the Apollo capsule being all that came back seeming like a waste when what was really incredible is what followed. That we could have gone to the Moon a hundred more times or put a hundred space stations larger than the ISS in orbit, or a combination of both, for the same amount of money- is a sad and depressing commentary on U.S. politics. The Military Industrial Complex (MIC) had no interest in HSF-BEO even after the 1980 Alvarez hypothesis made it clear an asteroid or comet could wipe us out like the dinosaurs. Space Solar Power is the only practical solution to powering civilization carbon free and mitigating climate change and this global warming was also known well before the turn of the century as a possible threat. Yet the DOD will have none of it.
I have written at length on the mountains of treasure being expended on new stealth bombers and missile submarines and modernizing ICBMs and all that goes with a “credible” nuclear deterrent. In my view space is the only place all these problems can be bundled and solved in one fell swoop. But where is the profit in a insurance policy for humankind? Our short lives insure we do not care about the world ending and instead want only what we can get in our own time. That we are not focused on establishing a permanent human presence off world is a red flag our species might not be intelligent enough to survive. It may be our selfish genes are translating into neoliberalism and that great filter is dooming us, and most intelligent life in the universe, to extinction.
The engines developed or proposed during the first space age in the 1960’s make those used now seem like very poor efforts. Not building vehicles to use these engines was one of the critical wrong turns made by NASA. Anyone familiar with Apollo generally considers the Saturn V to be a tremendous machine with power to spare when in reality it was much smaller than what NASA thought would be required. Until John Houbolt managed to convince them Lunar Orbit Rendezvous (LOR) would allow a smaller rocket, much larger design variants, collectively referred to as “Nova”, were the plan. The most likely Nova would have used 8 of the F-1 engines used on the Saturn V and, using F-1A engines, would have had a total of 14.4 million pounds of thrust compared to the Saturn’s 7.6. And this is where a comparison with present engines becomes interesting. The current 440,000 pound thrust and 550,000 pound thrust Raptor and BE-4 engines have less than a third of the thrust of the 1968 F-1A engine. The shiny starship will require 31 engines to generate 16 million pounds of thrust. Adding one more F-1A to the 1960’s Nova design for a total of 9 engines would provide the same total thrust. As stated earlier, when trying to make reusability a break even proposition, the more engines the higher the cost of turning around the vehicle for another flight. Thirty-one engines is a self-defeating proposition if ever there was one.
Let us entertain the option to succeed instead of fail by reviewing a few certain conclusions. It is certain we can make the F-1B, the recently modernized version of the F-1A, and mass produce large numbers of them. It is certain (courtesy of the flagship company) we can land back liquid fuel first stage boosters on ships at sea downrange of the Florida launch facilities. And it is certain we must have “Fat Workshops” to enable any long-term human presence BEO due to the prerequisite Near Sea Level Radiation One Gravity environment (NSLR1G).
Some Nova vehicle designs studied were extremely large and the proposed MM 1C used no less than 18 F-1A engines for a total thrust of over 32 million pounds, placing well over 400 tons into Low Earth Orbit. The 60 ft. diameter upper stage would have allowed for an optimum double-hull Fat Workshop for use as the fundamental building block of a Cislunar Infrastructure. Regarding re-use… the recent development of geared-turbofans for airliners gives a clue as to the best path to follow. The new and very expensive super-alloys used in the compact gearbox enabling geared-turbofan technology can likewise be applied to turbopumps and building the largest practical turbopump is key. The reason the large pumps are important is while combustion instability may be a limiting factor in thrust chamber size a single turbopump can supply two chambers. One large turbopump consumes half the maintenance time and resources as two smaller ones so those 18 engines can use half as many turbopumps (and technically become 9 instead of 18 engines).
The same rationale applies to hydrogen engines and the largest made now are the RS-25 and RS-68A at 512,300 and 705,000 pounds of thrust. The Aerojet M-1 was developed until funding ran out in August of 1966 and would have produced 1.5 million pounds of thrust to start with and more when developed further. These thrust chambers in the 2 million pound thrust range and large turbopumps feeding pairs are the only way reuse is going to break even for BEO missions and most efficiently enable a Cislunar Infrastructure. There is no cheap. Private efforts have not been able to manufacture them and only state-sponsored programs like those that produced the F-1 will make it happen. This is of course the antithesis of NewSpace dogma and why NewSpace is a pernicious ideology and has done so much damage.
The ISS proved beyond any doubt that sending up little pieces and assembling anything in orbit is a complete waste of time and will accomplish little at astronomical expense. Only scaling up beyond what was necessary to reach the Moon has any chance of expanding humankind into the solar system. With a launch mass of over 12,000 tons for a Nova MM 1C and 3,000 for a Saturn V, and lofting 400 tons into LEO versus 100, the obvious conclusion is we are not building rockets to the appropriate scale if we are ever to effect Human Space Flight Beyond Earth and Lunar Orbit (HSF-BELO). The rocket stage currently being landed on recovery vessels for reuse masses around 29 tons at shutdown while a Nova class stage as described would mass over 650 tons. The Nova stage is only about 30 feet taller but over 7 times wider at the base.
They are going to need a bigger boat, though landing back 650 tons of stage is not so extreme considering the maximum landing weight of the largest cargo jets are approximately 400 and 600 tons. The shiny starship will supposedly reenter and reuse the entire 2nd stage but, realistically, expending the second stage tankage while recovering the engine module is the likely necessary sacrifice to the rocket equation. The shuttle External Tank (ET) was about the same length but only half the diameter of this Nova second stage. Philip Bono, who was the father of the Vertical Take-off Vertical Landing (VTVL) concept in the early 1960’s, proposed using a lower thrust setting rocket exhaust plume to absorb heat and shield a stage at reentry speeds. Using stainless steel construction and a percentage of propellants to bring the second stage back down- and then more propellants and landing legs to land- would incur a significant payload penalty. But…as I inferred, if the scale of payload matches the resources expended to turn around the vehicle then it can break even. Getting that Fat Workshop on the way to the Moon is the trick and this is where 30 million pounds of thrust at lift-off becomes necessary to make any kind of reuse scheme worth the trouble. No free lunch.
To support missions beyond the Moon to the outer solar system a Super Heavy Lift Vehicle (SHLV) program to enable building a cislunar infrastructure is the first step. Cosmic ray water shielding must be acquired from the lunar poles and brought up to the waiting workshops (the “Fat Workshop” concept) before any long duration human missions are possible. Once these crew compartments in Low Lunar Frozen Orbit (LLFO) are shielded then humans can again leave Earth’s gravitational field and return to the Moon to maintain a permanent presence. After the water shielding comes the tether systems to provide artificial gravity and then a Lunar Cycler fleet and GEO human-crewed telecom platform network will follow. Eventually, true atomic spaceships using crew compartments from this production pipeline can depart for Ceres and the ocean moons of the gas and ice giants.
Unfortunately, the NASA Space Launch System (SLS) and the NewSpace flagship shiny starship are both simply too small to support such an effort. Going four times larger is the necessity while billionaire hobbyists claim they can accomplish great things spending less than what NASA has on their Moon rocket. If space clown tourism and strip mining Earth orbit with tens of thousands of pieces of smallsat junk is their idea of great they need to find another hobby. NewSpace is all hype.
And so, we fail.
Ice on the Moon 