Apollo 13 - a disaster almost certainly avoided

Even before the launch, the Apollo spacecraft experienced 13 delays and malfunctions, which intensified when a serious oxygen leak was discovered on the way to the moon 

For the first episode in the series - Apollo 11
For the second episode - Apollo 12

introduction
The uniqueness of the Apollo 11 and Apollo 12 flights was that they landed in flat areas. The uniqueness of the Apollo 13 flight was that it was supposed to land in a mountainous and difficult place to land, in the Far Mauro region. 3 complex missions were assigned to the Apollo 13 pilots.

Space scientists saw the launch of Apollo 13 as a journey aimed at discovering one of the most hidden secrets of the universe in which we live and surrounds us - it is the secret of the age of the moon and also the secret of the age of the entire solar system. Space scientists believed that Apollo 13 would bring back soil samples and evidence that the age of the solar system is over 5 billion years.
These hopes were based on the assumption that the landing site contained ancient rocks from the beginning of the moon. These rocks probably got there from a depth of 100 km. With their help they hoped to reconstruct the geological history of the moon until its beginning.
The basis of these hopes is the hypothesis of the impact of a huge meteorite in a place hundreds of kilometers away from the Para-Mauro some time after the formation of the moon. The fragments of stones and rocks that were thrown from the Para-Mauro as a result of this impact, were covered over the years by a layer of dust and rocks called regolith (this layer is the result of prolonged geological processes that took place on the moon, including meteorite impact and volcanic activity. The thickness of the regolith is a few meters to tens of meters.
Although the results of the first two landings proved that the moon is a lifeless planetary object, they did not despair of finding signs of life on it after all. A new push for this was given, when a mysterious factor was discovered in the soil of the moon that kills bacteria. The soil samples brought back by the Apollo 11 pilots were exposed to 3 types of bacteria. In a short time these bacteria were killed by a powerful agent. On the other hand, no injuries were found in the people who were exposed to the lunar soil. Plants grown in lunar soil developed faster than in the most fertile soil on Earth

The mystery that continued to surround the germicidal agent in the lunar soil led to the decision to keep the astronauts in quarantine for 21 days after their return to Earth.

The scientists found hydrogen on the moon at a rate of 1/20,000,000, which probably indicates the presence of water in the lower layers of the lunar soil. This water is probably the product of geological phenomena. The existence of water will increase the viability of a plan to establish a research base on the moon.

The Apollo 13 pilots continued the tradition of their friends by naming the spacecraft after the hero of Greek mythology. The command cabin was given the name Odyssey after the hero of Greek mythology and the lander was given the name Aquarius. The team included James Lovell, Fred Hayes and Thomas Mattingly.

Two malfunctions could have postponed the flight from 11.4.1970 to 9.5 (11.4 was a postponed date. In fact, Apollo was supposed to start its journey on 12,3. A cut in the space agency's budget resulted in the postponement of the launch). One malfunction was technical - defects were discovered in one of the helium tanks and it was soon repaired. The second problem was medical. Charles Duke of the replacement team has rubella. It was feared that Wall, Hayes and Mattingly would also fall ill. Mattingly was susceptible to the disease and was replaced by John Swigert from the replacement team. Swigert passed fitness tests and team integration tests. After many consultations and on the recommendation of Lovell, the flight commander, the flight was approved. Swigert joining the team and thus avoiding another delay of the launch.

11.4 - the first day of the flight
The launch of Apollo 13 was no different from its predecessors. After the launch, the spacecraft was put into a terrestrial orbit to test its systems. At the end of this phase, the spacecraft detached itself from its terrestrial orbit, entered the lunar orbit and connected with the lander. The maneuver was performed by Swigert and broadcast on television. The broadcast lasted an hour.

Although there was a malfunction during the launch, but they overcame it. The main engine of the second stage died prematurely. The remaining four engines extended their combustion to compensate.

Unlike previous times, this time the third stage was part of the journey. This stage was equipped with a large amount of fuel. With the retrieval of the lander, this stage aimed at the moon to crash on its surface - 200 km from the landing site of Apollo 12. The purpose of the experiment was to activate the zeymograph and see how the lunar soil would react to this impact.

12.4 - the second day of the flight
According to the plan, the astronauts were supposed to sleep 10 hours, but they slept 5.5. hours only. They woke up alone. After that, they checked the spacecraft's systems and broadcasted impressions from the launch and in particular the moment when the malfunction occurred in the second stage of the rocket.
Swigert had to photograph the Sun's corona and a mysterious glow that surrounds the Earth and is visible in the sky at midnight. This glow can only be seen with a telescope. The space scientists assumed that the moon could be seen and photographed better. At first it was decided to cancel this experiment, because Sweigert did not have enough time to specialize in the use of the camera. Finally, it was decided that this experiment would be conducted while Sweigert would circle the moon alone, after his friends had landed on the moon.

Since photographing the sun's corona was postponed, it was decided that the astronauts would photograph the clouds and other weather factors on Earth for 3 hours. One shot every 20 minutes. This series of experiments had to be performed every day.

Swigert recalled that in his haste the rabbi forgot to take the work plan with him and submit the income tax statement whose last date was 15.4/60. He feared that he would be prosecuted as soon as he returned to Israel. The work plan was broadcast to him from the control center. As for the income tax issue, the spokesman for the Ministry of Finance announced that every American citizen in space automatically receives an extension of XNUMX days. Since Sweigert is not in American territory, he is entitled to this extension.

13.4- the third day of the flight

In order to enter a lunar orbit that is 105 km above the lunar surface, the flight path was changed. This offset was performed by the spacecraft's computer. Such great precision as was required to perform this task was beyond the powers of a human being. The engine was ignited for 3.4 seconds. Swigert took care of setting it alight. While firing the engine, the astronauts made a television broadcast in which they showed what was happening in the spacecraft during the acceleration time. The accelerometer did not respond strongly. A pencil planted by Wall on a string swung when the engine was started.

For two hours the tunnel leading to the lander and the lander were inspected by Lovell and Hayes. The first 30 minutes of the test were televised. At the end of these operations, the astronauts fell asleep for 9 hours. Lovell discovered that yesterday before they fell asleep an alarm signal had been heard, not much importance was attached to it. It was believed that the signal was heard due to a malfunction in one of the electronic devices in the spacecraft.

14.4 - The fourth day of the flight

Lovell and Hayes entered the lander a little before the scheduled time. The introduction was made for the purpose of testing the pressure in the helium tank. The pressure was normal. Then they took care of the "household". While Hayes was working on the landing, Lovell was busy taking pictures and sending the pictures to Houston as part of a television broadcast that was being made at the time. When the transmission ended, Lovell returned to the control room. Hayes followed him. His job was to lock the door. It was 55 hours and 55 minutes after launch and at a distance of 340,000 km from Earth.

At that time an explosion was heard. When you slam the door, there is always an explosive sound, but this time the sound was heard before Hayes slammed the door. This time the sound was too loud to be caused by the door. At first it was thought to be an insignificant electrical fault that could be isolated. Later Swigert saw the warning light. It turned out to be a very serious electrical fault. Swigert was the first to inform Houston that there was a problem. Lovell confirmed his message.

Hayes immediately stopped animating the door, replaced Swigert so he could concentrate on piloting the spacecraft, entered the starboard compartment and checked the systems. Later he inspected the three fuel cells that provide the power for the command cabin and the sustainment system. Fuel cell number 3 was out of order and fuel cell number 1 was getting weaker. Lovell looked at the oxygen pressure gauge. Fuel cell number 2 indicated zero. The pressure in cell number 1 is rapidly weakening. The situation was extremely serious. The three fuel cells did not work at all. The spaceship had reserve power in the batteries. These batteries were part of the Earth return system and were not intended for operation to the Moon or even back to Earth. When Wall approached the left compartment of the command cabin and peered out through the porthole, he saw the sunrise on some gas that was emitted from the toilet compartment in an incredible amount. It was the oxygen that was drained from fuel compartment number 1. Yes, Lowell saw parts depleting from the toilet compartment. A few minutes later, the astronauts were informed that they only had a supply of electricity left for fifteen minutes and another surplus to operate the electrical appliances for 12 hours. The oxygen supply in the spacecraft for landing purposes was enough for 15 hours.

The landing on the moon that was supposed to be carried out on 16.4/20 was canceled (according to the rules of space flights during this period, a landing on the moon should not be carried out in the event of a serious malfunction in the spacecraft's electrical network). One of the engineers of the control center said that he was following the spacecraft with a telescope equipped with a camera when what appeared to be an explosion. The engineer said that he followed the third stage of the launch vehicle on its flight to the moon and happened to also take pictures of the spacecraft during the explosion. An oxygen aura with a radius of XNUMX km was visible around the command cabin. It is evident in the photo that the oxygen leak was sudden at the time of the incident. Two possibilities were put forward for the formation of the fault.

A meteorite probably hit the toilet compartment and due to this an oxygen leak started which in turn caused a loss of power in the two fuel cells while the third cell continued to work intermittently. As a result, the engine of the service compartment is silent and the oxygen supply has decreased.

In addition, there was a breakdown in the heating and cooling facilities of one of the oxygen tanks, so the pressure in the tank rose up to 100 atmospheres and more, causing an explosion.

An oxygen leak from the toilet cabin resulted in an oxygen leak in the control room. The oxygen tanks provide fuel, electricity, oxygen for breathing and water. In order to avoid wasting power, the astronauts were instructed to stop the activity of the non-essential systems. In the command cabin there was a tank with spare oxygen that could be used to remove the drinking water that would remain in the water tank. This tank was isolated immediately after the accident to make sure that the oxygen that was needed for the return home would not be lost.

A state of emergency was declared. It was clear that the command cabin and the toilet cabin were useless. The only hope left for the astronauts to save their lives was the lunar lander, which served as a lifeboat for all its systems, especially its engines and oxygen system, a role it was not intended for at all. Thanks to reducing the activity of the spacecraft's systems and the lander's use of oxygen, there was oxygen for 112 hours while the emergency landing should have been carried out according to the emergency plan in 88 hours.

Due to a lack of oxygen in the command cabin, Lewell and Hayes moved to the lander and from there provided their friend with an oxygen swig. The flow of oxygen into the cockpit was done by leaving the cockpit door open. Lovell and Hayes also transferred the data from the control panel of the command cabin to that of the lander. At the time, they had to maintain the inertial navigation system without which they would have been lost. Swigert used battery power to power the navigation system. They had to quickly coordinate the lander's navigation system with the command cabin's main system and they did. The lander's optical instrumentation is simpler because it is not intended to be used for space navigation purposes. To conduct observations they had to turn the entire spacecraft. If they lost the navigation system of the command cabin, the only way to navigate would be to look at the sun and moon or the earth. The astronauts had to do this because the gas cloud that surrounded them did not allow them to observe the stars. The choice was to place the spacecraft in the right direction for the path change by measuring its position towards the Earth and the Sun using the spacecraft's telescope. Until this launch, no astronaut had navigated in space using this method.

This method was invented by one. From the space agency engineers before the Apollo 8 flight. The engineer invented a computer program that shows what can be seen through the telescope at any point during the flight. In order for the team to be able to turn on the engine to raise the spacecraft to the new orientation, that engineer came up with a program that would learn what the team needed to see to know that the spacecraft was heading in the right direction. The engineer feverishly fed the computer with data on the spacecraft's speed, time and position and thus received data on where to navigate, to see the sun and the moon through the telescope, so that he knew he was on the right path.

At a distance of 10,300 km from the moon, the lander's engine was activated for 30 seconds with the aim of putting the spacecraft into an emergency lunar orbit when the paraslanion point is 211 km instead of 105 km - the planned altitude. This maneuver comes to take advantage of the moon's gravity to return to Earth faster (the free return trajectory). If the engine did not work, they would try to start the weaker navigation engines of the lander or by manual operation.

The space scientists canceled a plan to accelerate the speed and thereby shorten the flight by 24 hours. This is to save fuel for the lander and subsequently land in the Pacific Ocean 17.4,1000 km from the islands of Samoa and New Zealand. In the event that a lack of oxygen was felt, they would have preceded the landing and it would have been carried out in the Atlantic Ocean.

Another mishap occurred when the astronauts failed to activate the rocket system to put the spacecraft into a slow rotation about an axis, which involved overheating from the sun's rays. The astronauts had to change the position of the spacecraft in relation to the sun every quarter of an hour.

At an urgent request from the US space administrator, Australia's largest radio telescope was recruited to help track Apollo 13 during the landing. The radio telescope with a 70-meter antenna is able to receive low-power transmissions and thus the astronauts could save electricity when necessary. The station personnel worked for about 12 hours to dismantle the telescope's normal receiving accessories and replace them with accessories provided by the American space manager to receive the transmissions. The radio telescope of the University of Manchester - England also participated in the operation.

England, France and Brazil put their navies on standby to help rescue the astronauts if needed. An English warship was ready in the Pacific Ocean to land the spacecraft there. The commander of the English fleet in the Far East was ordered to send ships from his fleet to the probable landing zone.

The space scientists took into account the possibility of disconnecting the toilet compartment from the spacecraft. After much deliberation, it was decided not to do this for two reasons arising from uncertainty.

The service cabin served as a shield for the thermal cold of the command cabin from the immense cold that prevails in space. Exposing the cold to the space conditions for a long time could have changed its properties. The cold could have lost its properties and would not have been able to withstand the tremendous heat created while entering the atmosphere.
The navigation computer in the cockpit is not programmed to fly without the service cockpit. The scientists did not have informative information and data about the computer's ability to work in space when the spacecraft's weight distribution changes massively.

15.4 - the fifth day of the flight

The spacecraft entered lunar orbit. In order to ensure their return to Earth, the astronauts turned on the lander's engine for 4:42 minutes (18 hours after the first start). The speed of the spacecraft was increased by 950 km/h and prevented the planned landing site from being missed. From the control center, Lowell was informed to tilt the telescope in a certain way, so that he would see the sun in the telescope in a certain position. In doing so, he assured himself and the control center that he was on the right path.

The spacecraft circled the moon only once (partially). When the spacecraft passed by the hidden side of the moon, contact with it was lost for 20 minutes. Hayes and Sweigert photographed the moon after the lander's engine was activated and the spacecraft succeeded in detaching from its lunar orbit, the impression was created as if everything was fine. Everything is in its place. This impression was only temporary. A warning light indicating a high concentration of carbon dioxide came on and the air in the spaceship thickened. The spacecraft's decontamination facilities were out of order and the lander's decontamination facilities were too weak and unable to withstand the load of a 3-day flight.

According to instructions from the control center, a new lithium hydroxide device was improvised. The lander had two large tanks and one secondary tank and two more small tanks in the backpacks intended for staying on the moon. All in all, the quantity was not sufficient. Lithium hydroxide was in various places. The problem was how to use it. The tanks of the lander had round connections and those of the command cabin had square connections. The tanks of the backpacks had round connections that fit into the sub-tank of the lander. It was decided to connect the square tanks of the command cabin with the oxygen tubes of the lander. The astronauts used adhesive paper, plastic bags, cardboard, etc. The solution was so good that it was not necessary to utilize the second large tank of the lander.

After checking the data in the control center, the astronauts were informed that the sensitivity of the alarm device against carbon dioxide was deliberately increased to allow as much oxygen saving as possible. In the experiments conducted in the laboratories, no harmful results were found from carbon dioxide concentrations 3 times greater than what was measured in the spacecraft. It must be remembered that very large concentrations of this gas can make people drowsy and put them into an eternal sleep.

The astronauts later complained of a cloud-like thing hovering in the cockpit and interfering with the spacecraft's rotations. The spaceship rotates around one axis every 2 minutes. It means cooling down and the temperature dropping. The temperature in the spacecraft ranges between 0 5 - 0 2, due to the cold the astronauts wore two white suits on top of each other.

It has been speculated that the toilet compartment may fall apart. The people of the space agency rejected this hypothesis, noting that even if such a thing had happened, it would not have hindered the rescue of the astronauts. Once the malfunctions were fixed and the winds calmed down, the astronauts devoted their time, according to the space doctors' suggestion, to sleep.

Lovell and Hayes did not spend the entire flight alone in the lander. Occasionally they alternated with Swigert so there were always two in the lander and one in the cockpit. The stay in the lander was usually devoted to rest and starting the engine for changes in the flight path.

When the spaceship was under the influence of the Earth's gravity, a problem arose regarding the vital reserves of oxygen, power and especially water that remained, on which the astronauts' lives depended. The greater the number of operating devices, the greater the amount of water consumed for cooling. For this reason, the large antenna installed for communication on the moon was activated. This antenna consumed too much power and was aimed with a hand crank to allow clear communication. On the other hand, the people of the control center claimed that the connection is fragmented as in the days of Operation Mercury. Only the systems for monitoring the air, for transmitting data to the control center and for radio communication were operating at full capacity. This reduction forced the crew to turn off the lights and therefore the work was done using flashlights.

The weather forecasters of the aircraft carrier Iwajima, which was sailing at the landing site, announced that a typhoon storm was approaching the area - the astronauts would be able to maneuver the spaceship so that it would move away from the place of the storm.

Two Soviet ships sailing in the Pacific Ocean changed their routes and headed for the landing site. The British Ministry of Defense decided to send 8 rescue ships to the Indian Ocean, to Mauritius and Rio de Janeiro. The space scientists feared that the cause of the malfunction would never be known and this is because the toilet compartment is discarded near the time of landing.
Despite the cancellation of the landing, one experiment was carried out. The third stage of the Saturn rocket crashed on the surface of the moon 200 km from the seismograph placed by the Apollo 12 pilots with a force of 11 tons of TNT. Shocks were recorded for 4 consecutive hours as in the Apollo 12 experiment. This time too it was as if someone rang a huge bell and the ink continued to be heard for a long time afterwards. The collision was on time. From a weak beginning, the signal gradually increased until it was 20-30 times greater than the signals received in the Apollo 12 experiment. When this signal was received, the scientists realized that the moon noise created in the Apollo 12 experiment was not a rare phenomenon.

Two options have been put forward to solve the reverberation problem
A. The outer shell of the moon is so fissured like a layer of unconnected bricks that the seismic signals reverberate like in a huge empty hall.
B. In the absence of an atmosphere on the surface of the moon, the collision between the lander and the surface of the ground causes a "wave of destruction" that spreads to a depth of kilometers inside the moon, while this wave of destruction spreads in a horizontal line along the surface of the ground, it continues to flow energy into the ground. This influx of energy causes the seismic signals to reverberate for a long time.

These signals were interpreted to mean that the unknown events that occurred on the moon 3.5 billion years ago, after its formation, were so great that they caused the material to melt to a depth of 50-65 km. It turns out that the sound waves penetrated at least this deep, before returning to the surface of the ground.

It also turned out that if the Moon has or had a molten core, it should be buried under a very thick crust. The seismograph did not detect any change in the signals that would indicate the existence of a boundary between layers of different materials. In the Apollo 12 experiment, it was hypothesized that the shock waves were trapped in a "loose sandwich" of gravel and the signal traveled along the gravel layer, being reflected from the lava layers above and below it. After a while the idea of ​​a "sandwich" was rejected, but it was still thought that the signals quickly dissipated and regrouped within the moon's gravel.

16.4 - the sixth day of the flight
Yesterday, a fear was expressed that the spacecraft would miss the Earth by 160 km. The word means doom. It was necessary to make a change in the flight path. It was decided that this change will be on 16.4. Although there was a risk of ruin, the timing of the change was not of the utmost importance. The change is possible at any time, preferably within 30 minutes.
A tilt lane change was made at the beginning of the day. The lander's engine was turned on for 7.4 seconds by Level 12 minutes before the deadline. In order to achieve maximum accuracy, it was decided that all the preparations for starting the engine would be done by the astronauts themselves. They will also fire it and not trust the automatic systems. Changing the flight path slowed the speed of the spacecraft by 8.03 km/h. After shutting down the engine, the small navigation engines were activated to further reduce the speed. In total, the speed slowed down by 8.317 km/h.

In order to change the flight path, the rotation of the spacecraft around an axis was stopped. Due to this the temperature dropped even more and the astronauts had to wear long whites to avoid freezing. Shortly after the change, rotary motion was returned to the spaceship.

A warning light warning of a malfunction in one of the batteries of the landing pads was activated while the astronauts were preparing themselves to change the flight path. There was a concern that the battery was overheating. An order was received to stop its operation. Later the battery was turned on once more and the light came on again. It turned out that there was no damage to the battery. The light bulb came on due to a malfunction in the electric thermometer that measures the temperature of the battery. The battery continued to operate while ignoring the warning light. The lesson learned from this failure is that complete reliance on the control center's monitoring of the spacecraft's warning systems and mechanisms is impossible due to their unreliability and unexpected failures.

The lander is equipped with 6 batteries, 4 in the lower stage (landing stands) and 2 in the upper stage. Leaving one of them or even 2 out of use would not create a critical situation. Another, but insignificant, malfunction arose, which is a helium leak in the lander.

From tests done at the control center it became clear that the temperatures are not as low as described by the astronauts.

The weather at the landing site was getting worse. The typhoon spread in a radius of 160 km. It has been speculated that the spacecraft will make another change in steering to land somewhere else. Starting the engine in these conditions is quite complicated. These fears were dispelled after the weather improved. The USSR sent two more ships to the landing site.

17.4 - the seventh day of the flight

In the morning of this day, the last day of the flight, the temperature in the spaceship dropped to - 0 C 10 . At the control center in Houston, they trusted that the astronauts would only have to stay for a relatively short time in the command cabin, what's more, the temperature will rise somewhat when the systems are activated in preparation for the landing. Evidence of the cold that prevailed in the spaceship is the fact that the frost continued to cover the inner sides of the spaceship even when it landed in the ocean waters.

On this day the water ran out. The astronauts had access to the water in one of the lander systems, but they did not touch it. This system was necessary for cooling during the return through the atmosphere so that the sun's rays would not overheat only one side and especially the side where the fuel tank is. 7 hours before landing the astronauts swallowed energy pills to be more alert and alert for the landing. The spacecraft's systems were also tested. The landing was carried out in several stages
1. The flight path would have put the spacecraft at too obtuse an angle into the atmosphere and would have caused the command cabin to heat up. The small navigation engines of the lander were activated for 20 seconds and ensured entry at an angle between 0 6.75 - 0 6.25.

2. Disconnecting the toilet compartment. The disconnection is done as usual using screws containing explosive charges. The explosion of the screws results in a disconnection between the two parts of the spacecraft. Unlike previous times, the toilet cubicle lacked self-motion this time. If in previous times this compartment would have moved away into the depths of space and thus a collision would have been avoided, this time the small navigation engines of the lander were activated to move the command compartment away from the bathroom compartment.

The disconnection is done in coordination with the control center. Swigert disconnected the lavatory compartment and Wall removed the command and landing compartment. When they moved away from the bathroom, the astronauts noticed that its side had been breached for a length of 7 meters and parts of it were depleted. According to an order from the control center, the astronauts rushed to photograph the cabin before it moved away from them.

The 3 batteries of the command cabin were filled by the batteries of the lander. Lovell and Sweigert who were in the lander at the time returned to the command cabin.

4. Disconnection from the lander. If in previous flights (except Apollo 9) the disconnection from the lander was done in two stages on the moon and near it this time due to the special conditions the lander disconnected near the earth. In order to avoid wasting power and electricity, the tunnel connecting the two spaceships was sealed and filled with compressed air. With the opening of the bolts connecting the two spaceships, the air pressure pushed the two spaceships apart. If the toilet cabin and the lander had not been disconnected from the command cabin, the entire spaceship with its crew would have burned up in the atmosphere, and this is because the parachutes would not have been able to withstand such a large load. The parachutes were designed to carry only the command compartment.

5. Entry into the atmosphere.

6. The landing. After a journey of 142 hours 54 minutes and 44 seconds, Apollo 13 landed 800 meters from the site of the beast. If in previous times the landing was photographed only from the aircraft carrier, this time it was also photographed from a helicopter. The landing was tested and tested for many hours before it was executed. Different landing methods were tested using spacecraft models in laboratory conditions and using computers. Once all options were exhausted, appropriate data and instructions were transmitted to the astronauts which resulted in the successful landing.
From the first medical tests Lovell, Hayes and Swickert were found to be healthy. Hayes suffered from a mild fever and nephritis. The three of them each lost about 4.5 kg of their weight.

The source of the malfunction that led to the cancellation of the landing on the moon

Two months of intensive research that included about 100 experiments with the help of a team of 300 people led to the discovery of the causes of the failure of Apollo 13. The investigation cost about a million dollars. In 1965, the specifications of the heating device for the oxygen tanks were changed. The North American Rockwell company, the subcontractor of Corporation Aircraft and the Space Authority did not remember that with the change of the heating device, the thermostats (regulators) must also be changed.

These changes required a voltage change of 65 volts while the thermostats worked at an initial standard of 30 volts. This 35 volt load caused staining and they could not fulfill their role - to maintain the temperature in the oxygen tanks. The heating element that was connected to the thermostats got very hot and the heat reached a temperature of 0 540. The Teflon insulation of the electrical wires near the heater at the bottom of the tank was destroyed. The damaged electrical wires are connected to a special fan that mixes the oxygen. When Apollo 13 reached the moon the two damaged wires moved closer together until they made contact. A short is created accompanied by an electric arc. This short was clearly recorded on the telemetry devices in the control center. The electric arc ignited the Teflon insulation of the wires and it burned slowly. While igniting other wires, until a vent opened for oxygen that burst out of the tank, blasted the cell wall and paralyzed the spaceship's energy sources. The special process of emptying the oxygen tanks, during which the malfunction occurred, was activated for the first time before the flight, due to disturbances that arose during the normal emptying.

The fire could have broken out in the oxygen tanks at any time, an explosion before the launch could have destroyed the entire launch pad. In the report of the investigative committee, it was stated that the malfunction could have been discovered before the launch, if they had carefully examined the devices.

The canceled research program

The Wild Mauro Mountains were the first mountainous area chosen for a manned landing and was therefore more dangerous than the landing sites of Apollo 1 and Apollo 12. Landing in a mountainous area required the highest precision. For this purpose, the lander was equipped with a large amount of fuel. The disconnection from the command post had to be done at an altitude of 15 km from the ground. After the disconnection, the command cabin would soar to a height of 90 km in its circle in this orbit around the moon. Swigert, who had to stay in the cockpit during his orbits around the moon, was busy photographing landing sites for the next flights.

The lander could hover over the surface of the moon for only 14 minutes. This is the time that Lovell and Hayes had at their disposal in the search for a suitable landing site. If he was not found, they would connect to the command room and return to Israel. Wall and Hayes were supposed to land on 16.4 about half a kilometer from the cone crater and stay there for 35 hours. This crater is extremely steep and relatively young. Its diameter reaches 300 meters and its depth is 100 meters. Its rim rises about 100 meters above the surface. The scientists believed that the rocks on the rim of this crater are material thrown from the depths of the moon. At the time of the meteorite impact.

Four hours after landing Lovell and Hayes would leave the lander for their first tour. On this tour they had to place several devices. Since they were tasked with placing a number of heavy and complicated devices, they were equipped with a special wheelbarrow called a rickshaw. The devices were placed on this wheelbarrow and transported to their location. The wheelbarrow is the size of a construction wheelbarrow with two wheels and handles are installed for pulling and pushing. It is able to carry 32 kg of equipment, soil sample bags and 5 cameras. The wheelbarrow was installed on the outer part of the compartment where the instruments were placed, on the back wall of the landing pad.

The astronauts had to place a seismograph and other devices capable of transmitting various data and findings for a year. Their second tour on 18.4 was intended for geological research. Wall and Hayes were supposed to collect soil samples while patrolling along a route of 1 km from the landing site, climb the slope of the Kon Crater and check the rift at a depth of 3 meters. Each tour was planned for 5 hours. The time they had left between one tour and the other was designated for rest and sleep.

epilogue

Paradoxically, this failure to land a manned spacecraft on the moon was an extraordinary success. The reason for this lies in the fact that from the moment the malfunction was discovered, the entire flight took place under conditions of complete uncertainty.. The flight was accompanied by many malfunctions and it was necessary to find ad-hoc solutions. Without security any solution would have been successful. It was a work of creativity to find unusual solutions that enabled the successful return of the astronauts to Earth. These solutions have a very high added value. It will be possible to use this experience in extreme situations in future space flights to the moon and Mars.

The weight of the Apollo spacecraft is 45 tons and its engines were specially designed for this purpose. The weight of the moon lander is 15 tons. From the moment the malfunction happened, the lander's engines were used to return to Israel. These engines had to withstand a load 3 times greater than what was designed for them and the success was great. This experience can testify to the great reliability of these engines.
The great luck of the Apollo 13 pilots was that the malfunction happened during the flight to the moon. If it had occurred after the lunar landing on their way back to Earth, the flight would most likely have ended in disaster.