I ask you to build tractors, but you build rockets?

SpecaX attaches great importance to the development of starships. The thrust of the 33 Raptor-generation engines is undoubtedly the second in the world. If the combustion chamber is pressurized, it may be able to achieve a thrust of more than 7,000 tons, which is the same as the Xinyuan-3 rocket.

But in addition to the engine development of the Raptor series, SpecaX also plans to try new tracks.

"Hello, I'm Wayne."

"Nice to meet you Wayne."

Musk and his close associate Tom Mueller met with a young white man who was neither humble nor arrogant and obviously had a lot of background.

Wayne: "I believe you already know our purpose."

Musk: "You are DARPA, the Defense Project Research Agency."

DRAPA is almost a private company controlled by the military forces in the Hexagon. Its public research content is nuclear propulsion technology.

Initially, the nuclear power engine of the FATS program was intended to be handed over to DARPA, but in the end, NACA formed JFT first, and DARPA became a co-researcher of JFT, responsible for the design and production of nuclear thermal engine components.

This was not a small order, but DARPA was not satisfied. Coupled with the constant stimulation provided by the Storm to the Air Force, they took the initiative to propose a new plan for the Department of Defense.

Wayne: "The military is currently being led by the nose. The space shuttle has completed all its missions in the thirty years from 1981 to 2011. It itself is just a pursuit of SSTO, but in fact the technology is far away. Far inferior, both practical and economical are not ideal.

It was right to start a nuclear-powered aircraft program, but a nuclear-powered space shuttle is ridiculous, especially when it pulls out old stuff from museums. What we need is something bigger, heavier, and more expensive. "

Tom Muller immediately knew what the other party wanted to do.

"StarShip, the starship can meet your requirements."

Wayne: "Yes, it has a mass of close to one thousand tons, which is ten times that of Endeavor. We can install more and larger nuclear engines on it, and we can also install unimaginable super weapons. At least it can have Several hundred tons of payload, right?”

Musk nodded quickly. The most commendable thing about the Starship's second-stage orbit entry plan is the orbit entry quality, but the payload of several hundred tons is definitely not available. The final overall mass must be below 300 tons. It would be good to have a payload of 150 tons. .

But how can you say dejected words at this time? Besides, starships can be upgraded!

"There is no problem at all, and the starship is not expensive. Even the final official version only needs half of the insulation tiles. The manufacturing cost will not exceed US$200 million, but it requires more than a thousand tons of thrust to enter orbit. Can a nuclear engine have this data?”

Wayne: "One is enough."

"I have seen your moon plans and Mars plans. Multiple refueling is really troublesome and difficult, but if it is a nuclear engine, it only needs to be refueled in low-Earth orbit, and it can easily carry out interstellar travel.

DARPA is willing to fund starships. If you agree, it will initiate a proposal next month. The total research and development cost of starships is currently less than 3 billion US dollars, right? Any DARPA sub-project can exceed this number. "

This almost implies that the forces behind DARPA are not short of money at all. In fact, SpecaX, a rookie supported by NACA, is very unpopular with the established military-industrial complex. But if you stand with DARPA, you are standing with the big shots in the Hexagon. Together.

They bring an unimaginable budget, and although they will take some of it in return, it is still enough for SpecaX.

…

"The manpower is too small, not enough. We need at least 10 B+, preferably A-level or above researchers."

Ye Changsi flipped through a stack of roughly bound papers under the light. It was not much thinner than "Introduction to Radiation Propulsion Technology", and the situation in front of Cheng Nankai next to him was similar.

"Introduction to Radiation Propulsion Technology" has been scanned into PDF and printed several times, but now it is only allowed to be kept in the basement. These things are really too important.

Two atomic technology experts and five assistants stayed in the basement for three days and basically finished the book.

This internal journal from the future is very valuable. The introduction in the first part and the collection of related papers at the end are the most important. It reveals to the two people what a truly feasible high-efficiency nuclear fusion method will be in the future, especially the most important The theoretical part completes the last piece of the puzzle in the field of fusion.

The most powerful one is undoubtedly the "Yu Qian formula". Academician Yu Qian, who does not exist in this world line, is a real genius. He actually used the weak interaction force to solve the problem of uncontrolled plasma making continuous reactions difficult to proceed when fusion occurs. problem, and has taken a big step towards the unification of the four forces of nature (strong force, weak force, electromagnetic force, gravity), which can rank alongside Einstein, Bohr and others.

As for the second and third parts of nuclear fusion propulsion technology, there are three types: plasma propulsion, radiation propulsion, and electric propulsion.

Plasma propulsion is similar to fission engines. They both heat the working medium (water, hydrogen, methane and other molecules) into plasma and eject it at high speed. However, the fusion engine can provide tens of millions or even hundreds of millions of temperatures, and the ejection speed is greater and can The fuel used has a larger molecular weight.

This technology has sound theory and a lot of previous experience, but its disadvantage is that it consumes fuel quickly and cannot carry out interstellar travel;

Electric propulsion is actually a Hall thruster, which is a nuclear fusion device used to generate electricity, and then uses electromagnetic fields to accelerate ions to ultra-high speeds and throw them out. It is a super-powerful electric propulsion of nuclear power. The specific impulse is very high and can reach more than 100,000 seconds. It consumes It has very little fuel, low thrust, and has the potential for interstellar travel, but its disadvantage is that it accelerates slowly and requires relatively high acceleration working fluids;

Radiation propulsion technology is divided into two types. One is passive radiation propulsion. The spacecraft/detector is equipped with a receiver similar to a light sail, and is then irradiated by a large radiation excitation device in the solar system, using lasers, alpha particles, etc. as power transmission media. , no additional propulsion medium is required, and the specific impulse has more than a hundred times the potential to increase compared to the upper limit of electric propulsion;

The second is active radiation propulsion, that is, the thrusters on the spacecraft generate radiation propulsion, which is also the most ideal spacecraft configuration. In theory, it can reach sub-light flight speeds, which is equivalent to the dream spacecraft.

Plasma propulsion and electric propulsion are technologies that humans have already mastered. It is not complicated to apply fusion technology based on them, but radiation propulsion... According to the conjecture of the original author Zhao Zongyao, it should be practical within about two hundred years.

Two hundred years, because radiation propulsion is so ideal, although using photons or alpha particles to accelerate does not require propelling the medium to an unimaginably high specific speed, the practical difficulties are also very high.

Photons have no mass but they do produce light pressure. Humans have already done solar sail propulsion experiments, and alpha particles will certainly work, but the problem is that both of these things have a mass so low that they are almost negligible. If you follow the original momentum formula, The thrust obtained by existing means may not even be as good as electric thrusters.