In the depths of the vast barren desert, boundless darkness shrouds a sea of death—that is Lop Nur, a forbidden area for life that is inaccessible. "There are no birds in the sky, and no grass grows on the earth. Thousands of miles are uninhabited, and the wind blows the stones and runs. "The Gobi Desert unscrupulously presents its unique surname to the people who come here.

The sun is blazing during the day, and the surface temperature of the vast Gobi Desert is as high as 40°C, and at night it is surprisingly cold. Small detachments shuttled between the camp and the entrance of the cave, and the sound of trumpets echoed between the mountains and the Gobi.

The headquarters in Beishan sounded a loud military horn, and the Beishan nuclear test site, which had been silent for several hours, became lively again. The soldiers quickly moved the iron cabinets, tables, chairs, beds and other supplies that had been packed up to the field, and the cooking team took out all the pots and pans, and a pair of red and swollen but attentive eyes told each other the feelings of sleepless nights. Not only are there the excitement of witnessing the nuclear explosion, but many more veterans are nostalgic for the test site, because this is China's first ground-based nuclear test. How can they not be thrilled to experience the historic moment of China's nuclear testing industry?

At this time, it was still pitch black on the Gobi Desert, and the battalion headquarters called to inform the companies to prepare for loading. The convoy in charge of the transfer has arrived at the Licorice Spring outpost, and there are still 10 minutes to go to the camp. After the convoy arrived, under the dim light, each company was nervously and orderly organizing the loading. The driver of the automobile regiment had not eaten breakfast because he was in a hurry, so the cooking squad took out the packed tableware and made breakfast for the comrades-in-arms of the fraternal unit.

Everything was ready, and the sky was slightly clearer. The crowd standing at the Beishan headquarters and looking out was stunned, and they saw a long line of smoke and dust dragging smoke and dust speeding in the direction of Beishan at the Licorice Spring outpost in the distance, which was a convoy of high-end cars, political leaders, responsible persons of major military regions, provinces, autonomous regions, and municipalities directly under the Central Government, and experts who participated in the nuclear test. It didn't take long for the Beishan Command to issue an order to board the car, and six large cars and dozens of large trucks started one after another, and for a time the traffic was rolling, the motors were roaring, and the dust was all over the sky.

Sitting in the car, Eleni looked at the smoke and dust outside the car window, and her heart was full of excitement and excitement.

Because she is about to witness the explosion of China's first atomic bomb.

Chinese scientists and engineers have built the first atomic bomb and are preparing to test it today, which is an implosion-type bomb with plutonium as fissile material.

As early as April 1943, China's nuclear program engineers discussed two ways to detonate the atomic bomb: the simpler way was to shoot a piece of fissile material directly into another piece, so as to reach a critical mass in an instant, and this speed should be very fast, as fast as 1 millionth of a second, otherwise a small explosion (the so-called "poof") may occur before the vast majority of the fissile material reacts, wasting the rest of the charge. In order to study this delicate detonation structure, China's nuclear program invested more than 30 expert engineers and three years of effort, and it was not until May 1944 that it was successfully developed.

Dr. Qian Wenchang, who personally participated in China's nuclear program, proposed another method: to direct the explosion of ordinary fissile explosives inward to a certain mass of fissile material and squeeze it into a very dense state. Since the critical mass of the fissile material is approximately proportional to the reciprocal of the square of its density, the greater the density, the smaller the critical mass, so that the fissile material in the subcritical state will be compressed to a critical state, thus initiating a chain reaction.

At the end of 1943, Chinese nuclear planners discovered that, according to the state of technology at that time, plutonium could not be used safely in a gun atomic bomb, because the metal plutonium contained another isotope, plutonium-240, which had a high neutron self-emission rate and a very low critical mass, so plutonium was very sensitive to early ignition and could easily cause a dud. The disadvantage of an implosion atomic bomb was that the detonator battery had a lifespan of only a few days and needed to be replaced frequently, and most of the parts needed to be removed when replaced, a problem that was not initially resolved. Later, it was based on Yang Shuoming's "genius idea" that it was finally resolved.

Scientists in China's nuclear program have also discussed a third explosion theory, the nuclear fusion effect, which was discovered in 1922. In May 1942, Yang Shuoming asked his scientists to conduct a feasible study of this type of explosion, but after careful discussion, the scientists believed that any such super bomb would have to have the high heat emitted by the fission weapon to explode, so the research on nuclear fusion was prioritized after the research on the atomic bomb. On the other hand, because this kind of nuclear fusion bomb has a very large military potential in theory, the Chinese side is reluctant to completely abandon it in wartime, so it authorized scientists to continue to study it.

By the second half of 1944, the design of the atomic bomb had already been completed, and it was only necessary to wait for enough uranium-235 to be shipped from the various "metallurgical plants" before it could be assembled. The implosion atomic bomb encountered technical difficulties in the structure of the projectile: the energy of the explosive explosion could not be aggregated to a single point. In the end, the scientists invited two explosives experts from the War Department to help design a spherical charge consisting of a cheese-like yellow TNX explosive sphere, and finally solved the problem of explosive energy wave aggregation. Qian Wenchang received instructions from Yang Shuoming to assemble an atomic bomb as soon as he got enough fissile material.

This date came in June 1944. The first atomic bomb in human history was called "Coconut", and its fissile material was 7.2 kilograms of plutonium-239 (the size of only one coconut), and next to it was a neutron source called "Chestnut". The neutron source is the size of a billiard ball and contains two elements, polonium-210, a radioactive metal with a half-life of 138 days, and 30 neutrons are produced in beryllium for every 1 million α particles it emits. Outside the plutonium charge and the "chestnut" is a neutron reflector layer composed of uranium-238, which reflects the escaping neutrons back into the fissile material. The detonation is initiated by a composite B explosive (known as "flint") weighing about 2,318 kilograms, which is compressed to the size of a walnut to achieve a dense supercritical state. The nuclear charge, reflective layer and high-explosive charge of the "Coconut" were mounted on 12 pentagonal spherical shells, which were combined with bolts into spheres.

In order to determine whether an implosion atomic bomb could explode, and also to give an account to the Chinese Congress, which had already allocated more than a billion silver dollars for China's nuclear program, China's nuclear program had to conduct a live-explosion test, codenamed "Artificial Sun," and the test plan had already been drawn up as early as the spring of 1944. At that time, Yang Shuoming and Chinese scientists envisioned that the explosion would be carried out in a container, so that if there was no explosion, or the explosion was very small, then all or most of the valuable plutonium could be recovered (the production cost of each gram of plutonium in a metallurgical plant was 130 silver dollars, which was 110 times the price of gold at that time, and the plutonium charge of "coconut" was worth 800,000 silver dollars), for which the Chinese nuclear program ordered a large steel container from China's largest boilermaker, "Hanyang Iron and Steel Company", which was large and heavy. The inner diameter is 3.12 meters, the shell wall thickness is 130 mm, the length between the two ends of the cap is 7.75 meters, and the two ends are welded and then wound with 0.98 meters thick steel tape, weighing 240 tons. In order to transport it from the manufacturing plant in eastern China to the experimental base, a wagon was specially modified and a 36-tire flatbed truck was specially built to transport it to the desert test site in the southeast of Xinjiang Province - Lop Nur.

If it weren't for Yang Shuoming's fierce opposition, scientists would probably have set up the first atomic bomb test site very close to Dunhuang. One of the reasons for Yang Shuoming's opposition was the safety of the Mogao Grottoes in Dunhuang, and the second was that there was no longer a large area of wasteland in the Lop Nur area that could be used. After inspecting several suitable sites, it was determined that Lop Nur was the most satisfactory site, which was crossed by rail, was within the limits of the air base and was not surrounded by local peasant reserves.

By October 15, almost all the scientists and engineers of China's nuclear program had moved to Lop Nur, the atomic bomb had been assembled, hung from a 30-meter-high iron tower, the ground was littered with cables and sensors, and everything was ready, but the weather conditions were not conducive to the explosion. The army weather observers who provided the weather forecasts for the test had been accurate in their forecasts, but on 15 October, the weather in the southern part of Xinjiang Province suddenly turned sour, with fierce winds, lightning and thunder, and showers. In order to avoid excessive accumulation of radioactive dust in a small area due to rain, the nuclear explosion must be carried out on a sunny day, in addition to the fact that the aircraft on the observation mission are not suitable for take-off in bad weather, and the electrical circuits and instruments used for the test are also at risk of short circuits due to moisture.

In the barracks of the Lop Nur test base, 16 kilometers away from the atomic bomb tower, many of Qian Wenchang's aides urged him to postpone the test for 24 hours, but Qian Wenchang remained silent. Seeing this, Yang Shuoming called him and several senior aides into his office and calmly explained to them that the explosion must be carried out according to the original schedule, one of the reasons is that the success of the nuclear explosion is extremely important to the course of the war and China's future international status, and secondly, every day of postponement of the nuclear test means that the war will be delayed for one more day, and finally, all the test personnel and security personnel are exhausted, and if the test is postponed, it will be postponed for three to five days in one go, so that these people can rest. In the end, Qian Wenchang agreed to conduct the test at the scheduled time, and the two left for a sheltered command post 8 kilometers away from the explosion site at midnight.

By the time the scheduled moment of the explosion arrived, at 4 a.m. on 16 October, the weather had not improved, with cloudy clouds and light rain and high humidity. Qian Wenchang delayed the explosion by 1 hour. At 5 o'clock, the weather cleared, and Qian Wenchang decided to explode in 30 minutes. The five soldiers guarding the tower received a call from Yang Shuoming, turned on the searchlights that had been installed in advance, illuminated the tower and the hut containing "coconuts", and then took several jeeps to the shelter command post 8 kilometers away. Yang Shuoming left Qian Wenchang there and rushed back to the base barracks by himself. Dr. Wang Jinchang, who remained at the shelter command post with Qian Wenchang, smeared his face, hands and arms with sunscreen and made a bet with a group of young scientists about whether an atomic bomb could explode.

At 5:39:15 a.m., Dr. Lu Yuming, a physicist at Nankai University, flipped the switch of the main transmitter, and then activated the second and third stage transmitters. Yang Shuoming lay between Zhang Xiaozhun and Cai Yi, thinking in his heart that if this precious bomb could not explode, the Chinese Congress would probably hold the most severe hearing in history after the war, asking where the more than a billion silver dollars had been spent. He half-jokingly said to Cai Ye: "Do you want to buy a house near the Capitol with me?" It's likely that we'll spend the rest of our lives in Congress. Cai Yi laughed, and Zhang Xiaoxian smiled and said, "The people in the Congress will definitely eat us." ”

Yang's worries vanished with the explosion that quickly occurred when the readings reached zero. The "Coconut" exploded at 5:40 a.m. on October 16, 1944, with an explosive yield of 26±32,000 tons of TNT explosives. Princess Elenie of the German Empire, who witnessed this spectacle at the time, wrote in her memoir: "It was like a strange appearance that mankind had never seen before." A huge green sun rises to more than 8,000 feet in less than 1 second...... Illuminate the earth and the surrounding sky. A huge fireball about 1 mile in diameter rose upward, changing in color, from deep purple to orange-yellow, spreading, and getting bigger...... A force of nature that had been imprisoned for thousands of years was freed from its own shackles...... I seem to have heard with my own ears God say at the opening of the world: Let there be light in the world. And so there was a light ......"

Even the less exaggerated Brigadier General Zhang Xiaoxiao described the explosion in a report to the War Department: "The whole field was illuminated by a blinding light many times stronger than the midday sun, a golden, crimson, purple, gray and blue light, which illuminated every Gobi and every valley with indescribable clarity and magnificence...... Thirty seconds after the explosion, a wave of air rushed in, violently impacting people and objects, and almost immediately followed by a strong, long-lasting, and terrifying roar, as if heralding the end of the world......"

Some people only saw the flash, but did not hear the loud explosion. These were the personnel in charge of another experiment, and they had some special foil in their hands, which they scattered out of their hands when the shock wave came, and the foil was blown several meters away. Observers have calculated in advance the distance traveled by the paper at different explosion yields, and then calculated the strength of the explosion based on the distance the foil was blown away.

After completing the calculations, they sat in a "gray wolf" tank shielded with lead plates and used a mechanical grab to dig up soil samples. A few days later, when Chinese scientists wearing protective suits entered the area, they found that the desert around the center had been stamped into a shallow saucer-like terrain, and the sand within a radius of 500 meters melted and condensed into a layer of jade-like emerald green hard substance, and in the center of the explosion was a pit with a radius of 52 meters and a depth of 3 meters, and the pit was extremely fine powdery dust. The 30-meter-high tower has been turned into gas, and the giant steel container that towers 800 meters from the blast and is fixed to the ground with concrete and the 40-ton steel tower outside it have also been turned into twisted scrap metal under the shock wave.

Lu Yuming happily said to Yang Shuoming: "The war is about to end!" Yang Shuoming nodded and replied, "Yes, wait until we throw one or two of these things into the Soviet Union and the Soviet Union." Then he calmly said to Qian Wenchang and the others: "I am proud of all of you. Qian Wenchang replied succinctly: "Thank you." ”

For Qian Wenchang, Lu Yuming, Wang Jinchang, Lin Deyao, Zhu Guangping, Hua Luoheng (a famous mathematician whose mathematical talent was instrumental in building the first atomic bomb) and hundreds of other scientists, their work is almost over, but the work of Yang Shuoming and the Chinese side is far from complete. Yang Shuoming first ordered the collection of radioactive dust data in order to evacuate residents within 50 kilometers in case of bad conditions; Then there was the issue of secrecy: the inhabitants of half of Xinjiang Province and most of Loulan heard the explosion, and although the shock wave had little effect on the shelter headquarters 8 kilometers away from the atomic bomb, it shattered many glass windows hundreds of kilometers away, reaching as far as Ruoqiang County in Loulanzhou. There was a great stir among the residents of Loulanzhou, and one of the first newspapers in the state to publish that day mentioned the explosion: "Probably an ammunition depot exploded. Even a blind girl saw the flash. ”

By 11 a.m., the explosion could no longer be kept secret from the outside world, and the command of Lop Nur Air Base was ordered to issue an announcement saying: "About a large explosion that occurred in Lop Nur Air Base this morning...... An explosion occurred at a distant Army munitions depot containing large quantities of explosives, pyrotechnics and chemicals. There were no casualties. The damage to property outside the arsenal was minimal...... The explosion produced toxic gas fumes, which could spread due to the climate, and the army authorities could temporarily relocate a small number of residents from their homes. But this report does not deceive all outsiders. An American engineer stationed at a metallurgical plant at DuPont later said to a local Chinese Air Force major general: "All the people at DuPont congratulate you. The Chinese major general, who was extremely surprised, immediately followed him up: "What did you say?" The engineer replied slyly, "This is the first time we've heard of the Army putting explosives, pyrotechnics, and chemicals in the same warehouse." ”

(To be continued)