Dreams of a great foolish carrier

Remember the bike about the development of the space knob ? Yes, it is not based on real events, but it very clearly illustrates the idea that a simple solution may turn out to be better than a complex one. The rocket built on the principle of the “big stupid carrier” (“Big Dumb Booster”) is not in the “smart-stupid” range, but rather “simple-complex”. The launch vehicles we are used to grew out of military ballistic missiles, and when designing them, efficiency was more important than cost. But, if we are going to master space, then we need a lot of rockets, and complex former military rockets become too expensive. And what if you try to make a rocket relatively simple, but cost-effective?

Briefly about other ways

In previous publications in the series , other ideas for facilitating access to space were described:

Reusability . The rocket is expensive, the fuel is cheap, let's use the rocket many times. If everything was so simple, then the Space Shuttles would fly now in dozens and hundreds per year. Reusable systems are very dependent on the cost of time and money to prepare for re-flight, and here the shuttles lost economic competition disposable carriers . Elon Musk is now engaged in reusability, but he still has a long way to move in this direction - there has not yet been a single flight of reused Dragon or Falcon, not to mention regular reuse so that you can evaluate the economic efficiency.

Air start . The idea of ​​launching a launch vehicle from a flying aircraft has been proposed in many projects . However, to date, only the light class PH Pegasus uses this scheme. Of the notable projects under development, the Stratolaunch project aircraft is being built for a heavier rocket.

Single Stage To Orbit . The idea of ​​a reusable spaceplane , starting from the airfield, going into space and returning back. The Skylon project is known, but there has been no noticeable news on it lately.

Space free launch . Space elevator, Lofstrom loop, space fountains, etc., and more. They write about it often, here, for example, a fresh review , so I did not make my own (or, you think, is it worth it?), But things are still there. Such technologies have three huge drawbacks:

1. Almost all projects require materials and technologies that humanity does not yet know how to do.
2. The cost of such a structure is truly cosmic, and it will be built for a long time.
3. Problems with the calculation of payback periods and the impossibility of operating a partially finished structure to confirm the concept.

First monster

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In 1962, Aerojet engineer Robert Truax proposed the Sea Dragon project. The two-stage launch vehicle was supposed to have a height of 150 m, a diameter of 23 m and a total mass of 18,000 tons. The rocket was going to the port, then it was filled with kerosene — first-stage fuel and nitrogen — with pressurized gas tanks. Then the rocket had to be towed afloat to the launch site. The support ship (it was proposed to use an atomic aircraft carrier) decomposed water into hydrogen and oxygen by electrolysis. Liquid hydrogen was filled with second stage fuel tanks, and oxygen was filled with oxidizer tanks of both stages. After refueling, the ballast tanks of the first stage were filled with water, and the rocket stood up in the water vertically. The launch was made from a partially submerged position, it was expected that Sea Dragon would be able to output approximately 500 tons to low earth orbit. The simplicity of the design was to ensure the cost of launching in the range of $ 60-600 per kilogram, many times less then the existing missiles.







The only engine of the first stage created the thrust of 36,000 tons, but did not represent a special technical complexity - the pressure in the combustion chamber did not exceed 20 atmospheres, and the fuel was supplied without complicated turbopumps, by pressurized gas (so-called displacing gas). The second stage engine had a thrust of “only” 6,350 tons, and the pressure in the combustion chamber was only 7 atmospheres. For comparison, the pressure in the combustion chambers of modern rocket engines reaches 255 atm (RD-191). The rocket hull was made of alloy steel with a thickness of 7 mm and was no more difficult than a submarine hull in production. In fact, the rocket was supposed to be produced at the shipyard. The project was reviewed by the shipbuilding company Todd Shipyards, which considered it feasible. Economic and engineering calculations have been confirmed by TRW, we are already talking about buying a section of the coast for the cosmodrome, but the NASA budget began to be cut. Due to the lack of funds, the entire advanced development department, which was involved in Sea Dragon and manned missions to Mars, was closed. And Aerojet could not allocate funds for the development of such a cyclopean project on its own.

Almost take off otrag

Lutz Kaiser could have been known for over thirty years as the first private rocket launcher. Zenger's student, Lutz founded OTRAG (Orbital Transport and Missiles) and persuaded Werner von Braun and Kurt Debuss to join the team after they retired from NASA. The idea of ​​a new launch vehicle was to use simple blocks that were to be mass produced and, therefore, be very cheap.







One CRPU (Common Rocket Propulsion Unit - “standard rocket block”) was a pipe 16 meters long and 23 cm in diameter. The block housed fuel tanks (kerosene), an oxidizer (nitrogen tetraoxide and nitric acid in equal proportions), boost (compressed air ). The tanks were separated by flat bulkheads. At the bottom, a simple engine with ablation thermal protection of the nozzle and a 2.5-tonne charge, valves, batteries and electronics was installed.







The design feature of the rocket was the batch installation of steps. First, the blocks from the outer part of the package worked, then the internal ones. According to calculations, three stages were needed to put one ton into orbit, from 4, 12 and 48 blocks. The package layout led to the fact that the rocket was obtained relatively short and wide, and, in theory, could launch large and wide satellites. To run heavier loads, you just had to take more blocks. From the point of view of the usual criterion for the ratio of the payload to the starting mass, the rocket turned out to be ineffective - in order to put 8 tons into orbit (a little more than the modern Union), a rocket with an initial mass of 800 tons (more than two times heavier than the Union) . In order to withdraw 128 tons, a monster with an initial mass of 12,800 tons was required (four times heavier than the Saturn V, which produced about the same amount). OTRAG should have won at the expense of economic efficiency. Mass production of structurally simple units, tens of thousands a year, should have made them very cheap.





Six engines on a test bench





CRPU Automated Production Line





Picture of the start of the super heavy version of OTRAG



In 1975, OTRAG signed a contract with Zaire to build a cosmodrome in the province of Katanga (now the territory of the Congo). From the point of view of physics, everything was logical - the spaceport was located near the equator, in a place convenient for astronautics. The first flights of four-block test rockets began in 1977.





Rocket on the launch pad.





Test run. One engine did not turn on.



A unique video of the visit of some high Zaire authorities and the very unsuccessful launch:





Problems began when politics intervened. First, developed countries feared that the OTRAG missiles would be used for military purposes. Yes, they would be extremely ineffective in such a role, but to the underdeveloped countries of Africa, any missile is better than nothing. Secondly, the developed countries did not want an economic rival to their launch vehicles. The USSR, the USA and France jointly launched a campaign to discredit OTRAG in the media and began to put political pressure on Zaire. In 1979, OTRAG was forced to leave the country. Tests in West Germany were extremely difficult for political reasons, and in 1981 the company built a testing ground in an even worse place - Libya. In 1982, West Germany joined the Treaty on the Non-Proliferation of Rocket Technologies, and the transportation of the blocks produced in the Federal Republic of Germany to Libya became impossible. Despite promises, Muammar Gaddafi immediately confiscated the test site, and Libyan engineers tried to continue the project. Fortunately (because it was clearly a ballistic missile development program, look at the launch ), nothing came of them, and the project was finally stopped. During the tests, about six thousand tests on the stand and about a dozen suborbital flights in a single-stage four-block configuration were carried out. For the years 1975-1987, the OTRAG project cost about $ 200 million.

Big silly carrier today

Lutz Kaiser is alive and quite actively communicating with private owners of the “new wave” - Armadillo Aerospace of John Carmack and others. Interorbital Systems is developing the Neptune rocket of the same layout:







And Armadillo Aerospace wanted to make a very similar Stig rocket and use it as a geophysical one:





Dramatic accident:





Among the notable projects, HEAT-1X is also worth noting, in which the design was also simplified by replacing the LRE with a hybrid engine on a fuel pair of liquid oxygen / polyurethane. Unfortunately, HEAT-1X crashed in one of the tests, the new version of the TM-65 Tordenskjold burned down during bench tests. Now Copenhagen Suborbitals make a new rocket.

In 2006, the Space Systems / Loral Aquarius project participated in the COTS competition (delivery of cargo to the ISS by a private company), but lost. A feature of the project was the use of an oxygen / hydrogen fuel pair, which is quite difficult for a “simple” rocket, and only one step to put 1 ton of cargo into orbit.



In Russia, the idea of ​​a “big silly carrier” is being implemented by the project “Taimyr” from the company “Lin Industrial”. Low-powered engines, non-cryogenic components of the fuel, modular package arrangement - all this should minimize the start-up cost. Heavier "Adler" and "Aldan" use the engine of the first stage of the "Union" RD-108 and the steering cameras from it, I suspect, for the same reasons - the engine is already there and has been produced for a long time in series.

Curiously, but sometimes the concept of BDB include Russian launch vehicles in general. For example, the Soyuz launch vehicle uses engines that are not at the limit of the capabilities of modern technology. But it is very reliable, produced in series, relatively cheap and therefore extremely successful. But, since our missiles were not designed specifically as simple and as cheap as possible, the question of the applicability of the BDB concept to them remains controversial.

Future

As for the future, it seems to me that this path is potentially very promising, and I have two arguments:

Technology argument

Modern rocket engine is a very complicated thing . Many complex parts made from special high-strength materials using complex manufacturing processes with very small tolerances on accuracy - all this can not be cheap. Now imagine a rocket engine, which is printed on a 3D-printer and specially designed to be simple. Yes, it will not be efficient from the point of view of physics, it will not have record figures for the pressure in the combustion chamber, the load or the specific impulse, but small-scale production of such engines can be very cost-effective. They also should not be reusable - at a certain level of technology, it will be easier to melt and print them again, than to try to sort out and inspect.

Argument from the history of technology

When did mankind truly master computers and microprocessors? When they began to appear in city dumps. In the 60s and 70s, powerful computers were relatively common and already influenced our lives. But for the next qualitative transition, even less powerful, but cheap and affordable personal computers were required. For the production of microcircuits, high technologies are required, but a separate chip can now cost a penny.

The same situation can be found in other areas. The Maxim machine gun changed the battlefields, but the next qualitative step was the Kalashnikov assault rifle - with a less powerful patron and a shorter range of aimed shooting, but technologically advanced for mass production conditions.

In aviation, jet engines made it possible to achieve first subsonic, then supersonic speeds. But now high technology is used to reduce the cost of flight, and supersonic passenger liners have become extinct.

It seems to me that these analogies can also be applied when trying to predict the future of rocket technology. The dialectic of development of launch vehicles may turn out to be used in the fact that high technology and the ingenuity of people will be used to create "stupid" rockets.

List of used sources

The main source besides Wikipedia is Encyclopedia Astronautica .