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

Qiongzhou.

On the edge of the beach closest to the land launch station, Xinyuan Company built a floating launch pad that can be towed, and there are two semi-submersible ships surrounding it.

The crane on the semi-submersible ship lifted a 5-meter-diameter black extra-long container with a steel structure on the outside, moved it to the top of the "mouth"-shaped floating launch pad, found the correct position, and slowly lowered it down until the tail was just right. until it hangs above sea level.

The workers on the floating launch pad took a moment to pull out a few metal ropes from the middle of the sea and tied them to the steel frame of the upper part of the container. These metal ropes were connected to the counterweight that had sunk to the bottom and could be lifted underwater. Motor retracts and retracts.

Next, the crane began to release the hook, allowing the container to be pulled down by the four metal ropes around it. The workers on the floating platform all stepped back in tacit agreement to prevent the straight steel ropes from suddenly springing open.

There is a rocket sealed inside the extra-long container, with a retractable fixed structure inside to keep it in the center.

This is an experimental test rocket, using the core first-stage polished rocket body of a Xinyuan-5 basic rocket equipped with an H280 liquid oxygen and liquid hydrogen engine.

It now simulates the scene of the Xinyuan 4 (Long March 18) rocket being launched at sea:

Since it is impossible for any land launch pad to bear the thrust impact of the Xinyuan-4 rocket, it chose a semi-underwater launch mode similar to the PPT rocket "Hailong".

When the rocket is transported from the inland river, the rocket body is completely wrapped in a spliced ​​oversized steel assembly box with a cross-section of 26*26 meters and a length of 260 meters. There is also a large area of ​​curved soft pallet on the inner wall of the assembly box to resist the rocket. It ensures that the rocket body's interstage and booster connection mechanisms are completely stress-free, which is equivalent to a movable assembly building with a dead weight of nearly 2,000 tons.

Before preparing for launch, a specially lengthened semi-submersible ship will arrive at the scheduled launch area with the super-large assembly box lying horizontally and assembled, and then begin to release the steel-structured deck outside the head of the assembly box. A part of the steel cable is fixed to the stern steel frame, and then water is injected into the hull to sink until the entire final container is completely floating.

The place where the rocket is launched is not found randomly, but in a fixed sea area. It is necessary to enclose a relatively calm coastal water area and pour cement on the seabed to create a seabed cement base weighing 150,000 tons. This only costs eight dollars. The cost is 90 million, and it can be done in a month. Anyway, all it needs is a big cement lump.

The special semi-submersible ship can sink 50 meters. When it starts to sink, the super assembly box will touch the water and float, and because of the 39 engines installed at the tail of the rocket and four solid boosters weighing more than 5,000 tons in total, The overall center of gravity is tilted back and floats upward. Although there is a lot of part exposed to the water, because it is held up by the structure in the assembly box, the rocket itself is not subject to lateral loads, so there is no need to worry about radial force.

At this time, there will be four 10,000-ton cargo ships with large cranes installed nearby. Multiple boats and divers will work to connect the outer steel frame of the final container with steel cables in four directions.

As the semi-submersible ship continued to sink, the steel cable at the tail of the assembly box began to straighten, causing the tail to be pulled down to reduce the tilt angle. At the same time, four crane boats cooperated with the operation to pull and assist in erecting the entire assembly container, 260 The 30-meter-high final container is immersed in water for approximately 30 meters, and is maintained vertically by steel cables at the bottom and around it.

At this time, the fuel ship has to rush over to refuel the rocket. When the first and second stage fuel of the rocket are completely filled, the total container and rocket will sink 50 meters in length due to their own weight, and most of them will still be exposed. .

Then the underwater operators transferred the hundreds of steel cables on the cement base from the underwater semi-submersible ship to the rear of the assembly box. Then the semi-submersible ship left the water, and the steel cables began to be pulled under the action of the underwater motor. Let the assembly box sink slowly until all parts except the load-containing part are exposed to the water and are submerged.

The buoyancy force of the submerged part of the final container is 120,000 tons. The rocket, steel structure, and cement base together weigh about 167,000 tons, which is enough to resist these buoyancy forces.

The crane ship separated the steel cable at this time and left together with the fuel refueling ship. Almost 50 minutes later, it arrived in the sea 10 kilometers away, waiting for launch.

During launch, the top end cover and box exposed to the sea are removed, and then the water drain hole in the submerged part of the outer wall of the assembly box will first inject 30,000 tons of seawater into the box, causing the water level in the assembly box to rise to 95 meters. The rocket is subjected to The buoyancy reaches 25,000 tons, which is the maximum force that the rocket body can withstand the limiting mechanism.

Then, under the action of multiple explosive bolts, the oversized waterproof doors on the four sides of the super assembly box flew out to one side in less than 1 second. At the same time, a huge amount of seawater poured into the box containing the rocket instantly. The limiting mechanism is disconnected at the same time.

The volume of the Xinyuan-4 rocket can bring more than 60,000 tons of buoyancy. When it is filled with water, the rocket that loses control will directly accelerate towards the sea surface under the action of buoyancy, just like pressing a table tennis ball into the water with your hand and bouncing up when you let go. Same.

The buoyancy of the rocket itself was enough for it to jump out of the sea level. When the final assembly box with the sea surface part removed was ejected a few meters away, the four boosters and the core first stage were quickly ignited, generating enough thrust before falling due to gravity.

The entire launch process, preparation, and operation of the Xinyuan-4 rocket are extremely complex, requiring more than 1,000 offshore workers, and a ship with a total displacement of tens of thousands of tons. The auxiliary work for these preparations will cost hundreds of millions of yuan.

The site has already been selected, and water of suitable depth has been found in an uninhabited area in Qiongzhou, and preparations are being made for pouring the underwater cement base.

The final assembly box itself is equivalent to the pressure hull of a crude giant submarine. Fortunately, the technical requirements are not high and only special steel is required. The construction progress of Huludao has reached one-third, and it will be completed and sent to the new building in another month. Nearby tributaries of the Yangtze River.

The rest of the auxiliary ships are basically ready-made. China has no shortage of special operation ships and can be easily mobilized.

This extremely complex launch system is already the best solution that the base can think of. When it was submitted to the Aerospace Development Committee in August, the veteran aerospace experts were shocked. However, after careful study, it was found that this is the only way to do it, otherwise the super The rocket couldn't launch at all.

When it was learned that such a crazy super rocket had already begun to manufacture prototype arrows and found a Huludao manufacturer to customize the final assembly, the Aviation Development Commission passed a resolution to "convert" it to the Long March sequence, and the engine was also given the number YF-94 , and then started preparations for launch with all efforts. After all, there are only less than four months until the first launch!

At the same time, Qiongzhou immediately conducted verification tests to inspect the engine and launch method.

It took the inexperienced team more than half a day to complete all preparations. Guo Shen, the on-site supervisor, once again checked that all systems were intact and issued the launch order.

Trapped in the water by steel cables, the container with the surface part removed began to fill with water from under the water. After a few seconds, a large amount of water splashed up as the bottom vibrated, and seawater rushed in crazily.

At this time, the chemical reaction vessel at the tail of the rocket body begins to activate, producing a large amount of nitrogen to drain the seawater in the engine pipeline and combustion chamber.

When the limiting claws fixing the test rocket in the container are released, the rocket immediately pops out under the action of buoyancy. When most of the rocket body is stretched out, the engine soaked in water successfully ignites once, and the high-temperature gas causes the surrounding seawater to immediately The vaporization produces a spectacular water mist that reaches tens of meters high and envelopes everything.

Immediately, a group of rapidly rising flames appeared in the water mist, pushing the test rocket out of the water mist that had spread hundreds of meters and flew into the sky.

Ten minutes later, the test rocket reappeared above the launch area and splashed down into the sea in a vertical attitude.

Multiple RCS around the rocket body immediately started ejecting gas, causing the rocket to fall sideways and float on the sea before it completely jumped out of the sea again.

Underwater launch and water recovery, a success the first time.