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When it comes to the manned moon landing program, I believe that most people first think of Apollo 11 and the first human Armstrong to land on the moon. But in fact, in the process of space exploration, there are countless astronauts who are not afraid of death and dare to dedicate, and many of them are not well known to the public. If you ask me if there is a miracle in the world, then the Apollo 13 lunar mission is definitely one of the most fantastic space adventures in human history. Today we're going to talk about their stories.
Many people think that the Apollo 13 moon landing program was a cursed mission from the beginning. 13, in our eyes is a very ordinary number. However, in the eyes of many Westerners, 13 symbolizes the coming of disaster. At the Last Supper, Judas, who betrayed Jesus Christ, was the 13th to take a seat at the table. People are taboo to travel on the 13th. In some planes, you won't even find 13 rows. In elevators, people would replace the 13th floor with 12A.
Apollo 13 was launched at 13:13 on April 11, 1970. This is the best launch time calculated strictly based on physics and space dynamics, but it has to be said that 13:13 added a superstition to the lunar mission. The three astronauts were Commander James. Lowell, Command Module Pilot Ken Martinley, and Lunar Module Pilot Fred. Hayes. However, just a few days before the mission, Ken Martinley learned that he may have inadvertently come into contact with German measles. If the consequences of measles symptoms appeared during the mission, it would be unimaginable, and NASA would have no choice but to temporarily replace people. The three astronauts who were finally determined were James. Lowell, Jack Swegett and Fred. Hayes, they're going to be in space for 10 days.
The Apollo 13 spacecraft is divided into three main parts: the lunar module Aquarius, which will lead two astronauts to the lunar surface. Command module Odyssey, where astronauts spend most of their flight time. Finally, there is the huge service cabin, carrying plenty of fuel, oxygen and necessities. When in lunar orbit, the lunar module separates from the command module and service module, followed by two astronauts landing on the moon and another astronaut remaining in the command module. During this time, the command module and service module will continue to fly around the moon. After the completion of the lunar mission, the lunar module re-takes off, re-integrates with the command module and the service module in lunar orbit, and finally returns to Earth. The whole process requires very precise calculations and no mistakes can be made.
As the third U.S. mission to the moon, after the launch of Apollo 13, everything began to work normally. Although the engine of the second stage of the rocket was abnormal during the launch, and the engine was turned off about two minutes in advance, the sufficient redundancy design ensured the normal flight of the spacecraft.
46 hours after the launch, the ground control center staff also quipped and complained: The condition of the spacecraft is so good that we are bored to cry. 56 hours after the launch, the 3 astronauts also did a live TV broadcast, showing people on the ground life in space. Jack Swegert performs in front of the camera how to move his body in a weightless state. On April 13, at 20:58, Commander James M. Lowell said goodnight to everyone. At that time, no one thought that just 9 minutes after the end of the live broadcast, disaster would quietly come.
● Space adventures
At 21:07 on April 13, 1970, the ground command center notified the command module pilot Swegert to agitate the oxygen tank in the service module. This is a routine operation to read more accurate barometric pressure data. Swigget came to the service module, turned on the fan for the cryogenic tank, and less than 3 seconds later, there was a loud explosion at the tail of the spacecraft.
The ground crew was all confused. After a while, Swift reported to the command center, "Hey, Houston, we're in trouble here. ”
Houston is home to NASA's Space Ground Command Center. The staff couldn't believe their ears and said, "This is Houston, please say it again." At this time the commander of the flight, James. Lowell said the most famous sentence in the history of space, and it is also a famous line that has been borrowed by countless film and television dramas in the future.
At this time, the ground command center was still trying to figure out what was wrong. The ship's various systems began to show anomalies, and two of the three fuel cells were broken. Judging from the gas volume and pressure of the liquid oxygen tank, one liquid oxygen tank is completely empty, and the other is also rapidly deflating. Fourteen minutes after the explosion, James. Lowell glanced out the window by chance and noticed that the spacecraft was leaking some kind of gas into outer space. They chuckled in their hearts. It turned out that it was the No. 2 liquid oxygen tank in the "Apollo 13" service module that exploded, which also caused the leakage of the no. 1 liquid oxygen tank. The shell of the service cabin was also blown open with a large hole.
The oxygen in the service chamber is stored in an ultra-low temperature liquid form and, in addition to providing oxygen, is also used to drive the fuel cell. Hydrogen and oxygen are mixed in fuel cells, eventually producing electricity and water. That is to say, in space flight, oxygen is not only the astronaut's life support system, but also maintains the navigation and power system of the entire spacecraft. Without oxygen, the entire spacecraft will soon stop working.
The moment the liquid oxygen tank was confirmed to explode, the astronauts already knew that they would definitely not be able to go to the moon on this journey, and even a safe return to Earth might be a luxury. They had never been trained on the ground how to deal with such a major accident. But I think this is not NASA's fault, if you ask anyone: Suppose the spacecraft's fuel cells are all faulty, oxygen is leaking, the command module is invalid, and the spacecraft is halfway to the moon, what should you do? Probably 99.9% of people will answer you, waiting to die.
But Gene Kranz, Apollo 13 flight control commander at ground command center, felt there was still a chance. He knew that the more critical the moment, the more he had to remain calm, not to transmit the emotions of anxiety and fear to the astronauts on the spacecraft
Immediately after, an unprecedented space rescue operation began.
● Miracle Rescue
There are two options for returning the ship to Earth. The first option is to activate the engine of the service module and quickly change the orbit of the spacecraft. It may have been the quickest way to do it, but the service module had already exploded, and the engine had been forcibly restarted, and no one was sure if it would bring more disaster. In addition, the spacecraft was already very close to the moon at that time, and the gravitational pull of the moon was very strong. If you force a U-turn, you may not only run out of fuel for a short period of time, but also face the possibility of a spacecraft crashing on the lunar surface.
The second option is to continue flying toward the moon, activating the engine of the lunar module instead of the service module as the spacecraft bypasses the far side of the moon, using the moon's gravity to throw the spacecraft into the return orbit. Obviously, the second option is much safer. The most important thing is that the oxygen in the command chamber cannot last long. The only hope of survival for the 3 astronauts is to hide in the Aquarius lunar module. Because the lunar module needs to fly autonomously during the landing on the moon, there is also a separate set of power supply, oxygen supply equipment and powered engines.
An hour and a half after the accident, the ground command center notified the three astronauts and decided to adopt the second return to Earth plan. While in space, let them enter the lunar module and use the lunar module as a temporary lifeboat. In addition, it is also necessary to quickly power off the command module "Odyssey" and leave a little power to re-enter the Earth's atmosphere before activating, because only the command module "Odyssey" can withstand the high temperature generated by the friction between the spacecraft and the atmosphere. The Houston Ground Command Center is home to countless scientists and technicians with extensive knowledge and experience, and only by giving them unreserved cooperation and trust is the only chance to return safely to Earth.
However, the time in the lunar warehouse is not good. The lunar module was originally designed to be sufficient to sustain 2 astronauts for 48 hours. But now you need to support 3 astronauts to survive for at least 3 days. This meant that they needed to shut down all non-essential equipment and put the ship into super power-saving mode. Food and water also need to be used sparingly. Without the heater, the temperature of the lunar module quickly dropped to 5 degrees Celsius, and the white vapor exhaled from the astronaut's mouth condensed on the cold control panel and window. Under extreme conditions, they also need to keep a cool head and agile movements, because if they press the wrong key, they will be doomed.
Even if you save money, the fuel on the lunar module is only enough to start the engine once. The staff on the ground accounted for various parameters over and over again to ensure that nothing was lost. Fortunately, the orbit change was successful at one time, and after bypassing the far side of the moon, the spacecraft flew away from the moon at a speed of 5400 miles per hour and re-headed for Earth.
But that's not all, a new crisis soon emerged. The lunar module's chemical apparatus for filtering carbon dioxide can only carry two astronauts, holding on for 48 hours. Just like the activated carbon filter of a household water purifier, there will always be times when saturation needs to be replaced. Excessive concentrations of carbon dioxide can lead to dizziness, inattention, memory loss, and even cerebral hypoxia and respiratory arrest. Some spare carbon dioxide filters are stored in the spacecraft's command module, but its shape is square, while the lunar module's filter is circular.
At the time of crisis, ground crews used tape, plastic bags, cardboard and a section of plastic tubes on the spacecraft that could be quickly found on the spacecraft to come up with a creative way to modify the carbon dioxide filter of the lunar module.
On April 17, 1970, after four days and nights of hard work, the three astronauts finally reached the final stage of their arduous return journey. At 10:43 on April 17, they returned from the Aquarius lunar module to the Odyssey command module, about to carry out the separation operation of the spacecraft. The service module will drift away from the command module, and when the lunar module is separated from the command module, it will fall into the Earth's atmosphere and burn up. Eventually, the command module would carry three astronauts and land in the South Pacific. Of course, the premise of all this is that all operations are not wrong. It was also the most dangerous part of the journey. The command module needs to cut into the atmosphere at a very precise angle, and if the angle is too large, the spacecraft will burn out. If the angle is too small, the spacecraft will be ejected from the atmosphere, that is, three astronauts will float in space forever.
At the same time, because the service module has exploded, although the service cabin will be detached from the command module, it is easy to see from the photos that the explosion caused serious damage to the entire spacecraft. No one was sure if the command module was still intact and whether the heat shield could withstand the heat generated by atmospheric friction.
On separating the lunar module, Swegt concluded with a "Goodbye, Aquarius, we thank you." ”
I believe that this sentence is absolutely from the heart, in space, the lunar module Aquarius has taken on too many responsibilities that it should not have performed, without which astronauts could not have had the opportunity to survive this long 4 days.
At 11:23 on April 17, the command module "Odyssey" was about to enter the atmosphere. During this period, the communication of astronauts will generally be interrupted for several minutes, but according to the accurate calculation of ground staff, this interruption will not exceed 3 minutes. That is to say, after 3 minutes, the whole world will know if they will be able to come back alive.
Everyone held their breath and stared dead at the command screen. However, 3 minutes passed, and the command module still did not respond. Ground Commander Jean Kranz tried to contact them.
Half a minute passed, and still nothing happened, and Kranz said again, "Odyssey, Houston is ready." Still not responding, Kranz kept repeating "Houston is ready." Everyone was motionless, and the atmosphere was suffocating.
Then we heard the sound of a cheering radio signal coming from the communication equipment, and then the sound of Swegert.
When everyone heard Sweggett's "okie over", everyone in the control center couldn't help but stand up and applaud, and the cheers instantly resounded throughout the center. Later, everyone learned that when the command module "Odyssey" cut into the Earth's atmosphere, the angle was a little smaller than the calculated one, resulting in 1 minute and 27 seconds more time to cross the atmosphere than calculated. Ground commander-in-chief Kranz said it was definitely the longest 1 minute and 27 seconds of his life.
Eventually, the U.S. Navy's search and rescue fleet salvaged the command module in the South Pacific, and the three astronauts returned home safely. Speaking of this, I believe everyone has a question, what is the cause of this accident?
● Epilogue
Afterwards, NASA formed a special investigation committee to comb through a large amount of data and try to find out the cause of the explosion. It turned out that Apollo 13's No. 2 liquid oxygen tank was a second-hand product from Apollo 10. And in the process of installation, it was accidentally damaged.
Just two weeks before the spacecraft was launched, the astronauts had their last act. As is customary, after each act, the staff needs to empty the liquid oxygen tank. The simplest and most effective way to empty liquid oxygen is to open the heating switch of the tank and volatilize the oxygen. However, on that day, the staff found that the oxygen could not be completely emptied. Therefore, the voltage of the liquid oxygen tank heater was increased from 28 volts to 65 volts. The thermal stability switch on the heater was not modified accordingly, causing the fuse to blow. Long after the oxygen was emptied, the heater continued to work, and the temperature inside the tank reached 500 degrees Celsius at one point. The insulation of some of the surrounding wires was burned, which caused the liquid oxygen tank to become an untimed bomb after the liquid oxygen was poured in on the day of launch.
It can be said that it was a temporary negligence of the staff, which made the entire $400 million moon landing plan collapse in an instant, and also made 3 astronauts almost die in space. Before 1995, the Apollo 13 lunar mission was almost unknown to the world. Everyone habitually remembered those success stories until 1995, by Lang. The film of the same name, directed by Howard and starring Tom Hanks, was released, and the event became known to more and more people.
Some viewers who don't know that the movie is based on real events even scold after watching the movie: Hollywood can make this kind of film, and in real life, they can't come back alive. Got the director Lang. Howard cried and laughed, and it really proved how incredible the Apollo 13 rescue operation was. It has also been called the "greatest failure" in the history of the moon landing.
Finally, this incident reminds me of the end of the novel The Martian, Mark. The words that Vatney said after he was rescued.
He said: "In order to save my rotten life, how many manpower was mobilized, this number is so huge that I am dumbfounded." The cost of my survival must have exceeded hundreds of millions of dollars. It's all about rescuing a nerd who studies botany. Why bother? But I thought about it and probably knew what the answer was. If a climber gets lost in the mountains, others will form a rescue team to help. If a train goes wrong, people start lining up to donate blood. If there is a major earthquake in any city, people all over the world will send first aid supplies. This is the essence of human beings, existing in every culture of the world, without exception. Of course, there will be some indifferent everywhere you go, but the number of people who will care is definitely far greater than the indifferent guys. Because of this, there are billions of people who stand up for me and help me in times of crisis.
How could this not be the case with operation Apollo 13? At the moment of the accident, there was only one thought in everyone's mind, that is, to take them home at any cost.