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

Expanding the International Space Station is a big project.

First of all, ISS is an international cooperation project, and it really lives up to its name.

NACA has a profound background in deep space exploration and aerospace power, but it is not good at the construction of large-scale on-orbit spacecraft.

The reason has to be attributed to the space race of the last century. Aramco became a little swollen after winning the moon landing in the Apollo program, and did not care much about launching a few modules in low-Earth orbit.

Of course, it’s not that NACA is not interested in carrying out permanent personnel missions in low-Earth orbit. In fact, this project is already included in the space shuttle program.

The first space shuttle "Columbia" to enter service should actually be called a space laboratory rather than a simple shuttle vehicle. It has a lot of experimental equipment installed in its cabin, and it does not have the retractable cargo compartment of the later space shuttles. can stay in orbit for a long time.

What's more, a space shuttle weighs more than 100 tons, which is larger than the original space station of the former Alliance.

After the alliance found that its national strength could no longer support the moon landing, it chose to build a low-Earth orbit space station and accumulated considerable experience.

At first, Ami wanted to bring European partners together or even do it alone on the International Space Station. However, due to a lack of experience and a sharp decline in funding after the end of the Cold War, Lucia had to be brought in in the end.

Over the years, sometimes when the two families quarreled, Lucia would say that the International Space Station should be "separated" because the ISS would really not be able to survive without the functional support of Lucia's module...

Even with the expansion, Lucia’s opinion cannot be ignored.

Montal consulted the Lucia Space Agency privately before holding a meeting on the ISS, and received ambiguous feedback.

Yuri Borisov published a lot of nonsense through RT. After careful consideration, Montal only saw two words: asking for money.

The Lucia Space Agency has become a favorite because it is unable to join the current moon landing race. A few days ago, after the module jointly developed by Italy and R\u0026D docked with the Tiangong Space Station, they also stated that they would cooperate with China on a series of space stations.

Of course, the specific content is also vague. In fact, the idea has been made long ago and is waiting for a price.

Now Lucia can contribute to the ISS expansion, but the money must be in place, even if the main truss part needs to rely on the space shuttle.

Montal had nothing to do about it, and Lucia really grasped the pain point. After all, NACA couldn't build another super space station.

However, as the Advance gradually took shape in space and became closer to a complete body, the Senate became even more dissatisfied, and expansion must be necessary.

Not only must it be expanded, but it must also be advanced. Even if it cannot achieve the terrifying quality of the Forward, it must at least have something that can be promoted.

…

"Four RS25s, or three RS25Es?"

Teams from Rocketdyne and Boeing got together to discuss engine selection for the new shuttle system.

It is not difficult for Endeavor to replace the three huge RS25 engines with nuclear engines. JFT has already given the size data of the corresponding engines they are actively manufacturing, and the difference is not big.

The focus needs to be adjusted a bit. Fortunately, the Endeavor has been dismantled and only the skeleton is left to be renovated. It can be overcome with the assistance of modern computers.

The problem is the launch system.

The original space shuttle launch system was very special. During launch, the space shuttle lay on a huge orange fuel tank to supply fuel to the three RS25s at its tail. Two SRB solid boosters were bundled on both sides of the fuel tank to create a rocket. Approximately 2800 tons of thrust.

When the SRB's solid propeller burns out and separates, the space shuttle will continue to fly with the fuel tank until it reaches orbit.

The thrust of a single RS25 (at sea level) can reach 167 tons. Obviously nuclear engines do not have this capability. The advantage of the latter lies in specific impulse rather than thrust. Moreover, the FAA will never issue a takeoff permit to a space shuttle that starts a nuclear engine on the ground, otherwise People will have to storm Capitol Hill.

Endeavor, which is converted to nuclear power, needs to enter space as a payload rather than part of a rocket like the former Soyuz "Buran" space shuttle, so the launch system also needs to make major changes.

This seemingly difficult problem did not stump the engineers. In fact, there were many plans to convert STS into pure load transportation in the last century. Just take one and change it.

The nuclear-powered version of Endeavor still lies on the fuel tank and is equipped with four RS25 engines, but these four engines are installed on the other side of the fuel tank, opposite the space shuttle.

It is equivalent to moving the four engines of the original space shuttle to opposite directions, keeping the total thrust from being reduced.

These four engines are installed in a triangle with a circular pointed cone. They draw fuel for use by the engines like a space shuttle, producing a total thrust of 670 tons. The extra thrust is used to offset the dead weight of the new structure and to make up for the thrust angle. resulting loss of power.

The two sides of the fuel tank weigh more than a hundred tons on one side and up to ten tons on the other. Obviously, the four RS25s need a larger deflection angle, and the entire assembly must be tilted after leaving the ground, allowing the two SRBs and four RS25s to tilt. The thrust intersection point coincides with the overall center of gravity.

In this way, the space shuttle is no longer "leaning back" like before, but "lying forward". Like H2, it lies on the rocket and is sent into space.

This plan is very similar to the 1125K "Energy" rocket. Both can carry a load of more than 100 tons on the side of the rocket. The original idea was to develop a giant rocket to replace the Saturn V based on STS.

The difficulty was low, the plan had been pre-researched, and it was quickly determined as the basic configuration, which became the launch method of future nuclear-powered space shuttles.

What Boeing and NACA are now struggling with is whether to reuse the four engines on the side of the fuel tank.

The original purpose of the design of this plan must be to use it. After all, the triangle body with four RS25s installed in that shape is designed to return to the atmosphere, so as to bring back the extremely expensive four hydrogen-oxygen engines, which are close to 200 million US dollars.

Otherwise, just follow the SLS routine and put it at the bottom of the fuel tank, which can reduce the workload by more than 50% in one go.

But the problem is how to recycle the propulsion part. Boeing now has two options:

The first is to optimize the triangular body into a central lifting body, which can be used as a deformed micro space shuttle to glide and land with an engine;

The second is that there is no wheel splashing into the sea and recovery, and it falls directly into the sea during landing.

Both options have their own advantages and disadvantages. One is safer and the other is more worry-free, but both require a greater workload. Now, as a giant that continues to annex various near-monopolies, Boeing has tasted the bitter consequences. It is the main contractor of NACA. There are already too many tasks to do. Reduce the workload.

Moreover, Rocketdyne's attitude also made them more entangled. A single RS25 costs more than 50 million US dollars, and there is indeed a need to recycle four RS25s;

But Rocketdyne also said that they have developed a simplified structure of the chicken blood version of the RS25 (disposable). The thrust has been increased to 200 tons (sea level), the specific impulse and thrust-to-weight ratio have also been improved, and the price has been reduced to just over 20 million US dollars. If used For RS25E, three engines are enough.

Should he increase his workload and recycle an engine worth US$200 million, or should he save trouble and throw away nearly US$70 million in one go?

To reuse or not to reuse, that is the question.