Introduction to the Apollo program

An introductory chapter to the ongoing series on the Apollo program and the history of the space program as a whole
introduction

"I believe that our people should do everything in their power to achieve the goal we set for ourselves. Landing a man on the moon even before the end of the current decade and returning him safely to Israel." These were the words of President John F. Kennedy on May 25, 1961. The Apollo program was the last step in the US's efforts to land a man on the moon. First in single-manned flights (Mercury), then in double-manned flights (Gemini) and finally in the Apollo spacecraft, each of which was manned by three astronauts. Note the date on which President Kennedy delivered his statement to the Senate. This date is close to April 12, 1961, the launch date of Yuri Gagarin, the first man launched into space. This Russian operation proved the supremacy of this power in space exploration. The USA's disappointment presented it with a great challenge to clearly show its superiority in this new and magical field. Everything the Russians can do the Americans will do better and stronger. And indeed, the scientists of the USA managed to realize the hopes they had planted in them. President Kennedy's declaration became a resounding success, although several failures and one disaster (Apollo 1) befell NASA.
The Russians were pioneers in various fields. They were the first to send a man into space, the first to land unmanned spacecraft on the moon. Their plans after that were pale, though what they did should in no way be underestimated. The reasons that clouded their progress in space exploration stemmed from weaker computer technology, backwardness in electronics, difficulties in miniaturization, excessive secrecy and the involvement of politics in space exploration. These constraints forced the Russians to slow down their progress until they had to give up landing a man on the moon and began to emphasize other areas of space exploration.

President Kennedy's 1962 speech about the need for a flight to the moon

The extensive experience gained in the Mercury and Gemini spacecraft gave the green light to the Apollo program. NASA scientists were well aware of all the problems related to approach maneuvers between spacecraft, docking spacecraft, extravehicular activity and a two-week stay in space (Gemini 7). The program began on February 26, 1966. On this day, an unmanned Apollo spacecraft was launched for the first time. Landing a man on the moon is extremely complex and several stages must be distinguished beforehand and they are:

• A. Unmanned flights to test the spacecraft in all its complexity and all the systems directly and indirectly related to this large enterprise. This phase began as mentioned on February 26, 1966 and ended on April 4, 1968.
• B. Manned test flights on a national route - Apollo 7, Apollo 9.
• third. Manned test flights in lunar orbit - Apollo 8, Apollo 10.
• d. Landing on the moon - Apollo 11 to Apollo 17.

A lot of work went into ensuring the safety of the astronauts and the integrity of the spacecraft. The manned flights of Apollo 7 and Apollo 9 did not lead to an immediate landing on the moon. The space scientists did wisely when they tested the spacecraft once in terrestrial orbit and once in lunar orbit. First the service compartment and the command compartment were tested in terrestrial orbit (Apollo 7) and then in lunar orbit (Apollo 8). Then the lander was put to the test in terrestrial orbit (Apollo 9) and in lunar orbit (Apollo 10). Only when they realized that the three parts of the spacecraft were functioning successfully was it decided to land on the moon. There were scientists who recommended that the landing be carried out on the Apollo 10 flight. However, this proposal was rejected. After the flight it became clear that the non-implementation of this proposal was justified. The spacecraft's communication systems were not reliable enough to land on the moon. Had the landing been made on this flight, it would have ended in disaster.

The scientists took a different precaution after the Apollo 1 disaster on January 27, 1967. This spacecraft was supposed to be the first manned flight in the Apollo program. During one of the training sessions the use of pure oxygen for breathing caught fire and resulted in the tragic deaths of Virgil Grissom, Edward White and Roger Chaffee. 18 months were required to assemble a new and non-dangerous atmosphere in the spacecraft. The long postponement proved itself and such malfunctions did not change. The serious malfunction in Apollo 13 led to the postponement of the flight of Apollo 14 by four months, in order to install an additional oxygen tank and improve various systems related to it.

There was no lack of malfunctions during the flights. Some minor faults and some serious, whether in the tunnel connecting the command cabin and the lander (Apollo 10, Apollo 14), whether in the lander (Apollo 10) or in the main engine (Apollo 16). Faults should be seen as natural for these systems consisting of 5.6 million parts and faults of such complexity are expected. In some cases intensive action was required to find their source, but all were resolved or could be ignored. Most of the failures resulted from a mistake by a technician, a defect in an electrical circuit, and more. A serious mishap was the explosion in Apollo 13. It was precisely here that the reliability of this mighty system was revealed. This malfunction had to cancel the landing and return to Israel. The only engine that was operational was the lander's engine. This engine was designed to operate on the moon only. It was not designed for interstellar flights like the Earth-Moon. The engine was put into operation and performed what was assigned to it (a last-minute design that had not been subjected to any tests before.) with great success above expectations. Apollo 13's landing is the only one aborted out of seven flights, that is, an 85% success rate.

Robots versus people
The Apollo pilots brought with them to Israel 427 kg of soil samples compared to 400 grams brought by the Russian spacecraft Luna 16 and Luna 20. The Russian lunar rover Lunakhud 1 worked for about 10 months in the Sea of ​​Rains and transmitted many important data about this region, but it was overshadowed with the introduction of a vehicle The space (rover) used by the Apollo pilots in the last three flights. The uniqueness of this tool is in expanding the field of action of the astronauts in a limited time. The Russian space scientists realized that they would not be able to catch up with NASA in landing a man on the moon and turned to the unmanned channel in order to achieve what they could not achieve with humans and stay in the picture. They succeeded in doing so. As mentioned, they brought to Israel samples from the surface of the moon and operated an unmanned research vehicle over it. These performers have demonstrated an improvement in their electronic ability and this should be treated with due importance. NASA scientists overshadowed the Russians in the successful operation of the rover and in the amount of soil samples they brought to Israel. It has been proven that manned flights are more beneficial than unmanned flights. Although an automated vehicle is of great importance (research in places that a human cannot reach for technical or biological reasons), the ability to learn, make unexpected repairs (Apollo 13 proved this) and decide what is better, is in the hands of humans and not machines.

Initial achievements

The Apollo program showed that NASA can also show primacy in space flights. For the first time, tiny research satellites were launched from spacecraft (Apollo 15, Apollo 16). American astronauts were the first to carry out an extraterrestrial activity not in terrestrial orbit, but at a distance of 300,000 km from Earth (the last 3 Apollo flights) and for the first time an astronomical observatory was placed on the lunar soil.
protection
Apollo pilots were equipped for their journeys with weapons. The astronauts set out to explore an unknown land. Although the moon is biologically dead, the possibility that bases of hostile and unknown entities exist on its surface cannot be ruled out. For defensive purposes, a weapon was an indispensable item on every flight (note: this article was written in the 70s). This topic may sound like science fiction. NASA took great care to ensure the safety of the astronauts. If there is indeed someone who is or has been on the moon, he has technologies that go beyond those currently found on Earth and he had the ability to neutralize weapons that could be in the hands of the astronauts. It is hard to believe that NASA was not aware of this. Equipping the astronauts with weapons had more psychological weight. to give a sense of self-confidence due to being in a completely new place).

Apollo program

With the launch of Apollo 11, the space scientists thought of making two more flights and switching to another program. The program was expanded to 10 flights until Apollo 20. The last one will stay on the moon for two weeks. The reality was different. The success of Apollo 11 was indeed intoxicating, but it led to unexpected reactions. Public opinion and some senators saw this flight as the fulfillment of President Kennedy's dream and nothing more. They amounted to a demonstration of American hegemony over the Russians. The Apollo program ended for her and therefore they decided to trim NASA's wings. They argued to the senate that a few kilograms of the moonstones are a waste of money and useless, what's more, more pressing problems like poverty have not been solved. The Vietnam War also took its toll and NASA surrendered. The last three flights were cancelled.
For eight years (1961-1969) NASA employed 420,000 people and the total number of employees related to this was three million workers. The employees outside of NASA were employees in the aerospace industry who were used for this purpose as subcontractors. The budget allocated for this was 25 billion dollars. 0.5% of its gross product for space exploration.
In memory of…
The Apollo pilots did not forget to commemorate the American and Russian astronauts who perished on Earth and in space by means of small memorial plaques and by giving the names of those who perished to the lunar craters (these commemorations were made on Apollo 11 and Apollo 15). In his will, Grissom, who perished in Apollo 1, said, "If we die, we want the public to understand. We are dealing with dangerous matters and hope that if something happens to us, the plan will not be delayed. Conquering space justifies risking human life."

 

meeting on the moon
Apollo 12 pilots Charles Conrad and Richard Gordon's visit to Survivor 3 has great symbolism. This time the astronauts visited a spacecraft from Earth. Next time it could be a spaceship from another planet.

 

Saturn 5 - the launch vehicle
With the exception of Apollo 7, which was launched by a Saturn B1, all Apollo crews were launched by a Saturn 5 rocket. Saturn 5 stands 121.32 meters tall (with the spacecraft and the escape tower) and weighs 2816.1 without fuel.

The structure of the missile
Stage 1 height 42.06 meters, diameter 10.6 meters, weight 2,174,000 kg, thrust 3,500,000 kg
Phase 2 height 24.84 m diameter 10.6 m weight 470,000 kg. Thrust 510,00 kg.
Stage 3 height 17.83 m, diameter 6.6 m, weight 118,800 kg, thrust 102,000 kg.
Instrumentation unit 1 0.81 height (meter) diameter (meter) 6.6 weight (kg) 2050.
Adapter 2 Height (in meter) 8.53 Diameter meter) 3 3.91 Diameter (meter) 4 6.6.

 

Escape system: height 10.06 m, diameter 1.2 m, weight 4,000 kg, thrust 66,700 kg

1. Guidance and control of the launch vehicle

2. The adapter between the third stage and the Shiro chamber, a truncated cone that stores the lander when it is folded
3. Upper diameter
4. Bottom diameter
5. See the structure of the spacecraft

 

The structure of the spaceship
The Apollo spacecraft consists of three parts - the command cabin, the service cabin and the lunar lander.
the control room
The command cabin is the home of the three astronauts on their journey to the moon and back to Earth. The shape of the cell is like a cone with a height of 3.23 meters, a base diameter of 3.91 meters and a weight of 5.6 tons. The cell is built from two parts that are connected together - a sealed inner shell and an outer thermal insulation. The first part is made of aluminum of variable thickness. The second part is made of stainless steel and weighs 25% of the weight of the control room. The main function of the thermal cooling is to shield the crew and the spacecraft's systems from the high temperatures created during the passage through the atmosphere upon the return to Earth.

 

The ablative material covering the thermal cold controls the rate of heat absorption, by its carbonization and evaporation. The entrance to the spacecraft is through a side door whose dimensions are 74 x 97 cm. Access to the lander is through a tunnel at the top end of the command cabin. The spaceship has five windows - two square sides measuring 33 x 33 cm on both sides of the astronauts' sides and are used for observation and photography. Two triangular windows in front of the side projections allow a forward view (over the top of the cell) and are mainly used for observations during rendezvous and engagement maneuvers. Another window is in the cabin door.

 

Most of the indicators and warning lights that must be continuously monitored are located on the main display panel, in front of and on either side of the three displays. Various indicators and switches are scattered in the crew compartment and even on the displays. Most of the navigation and guidance equipment is located in the lower equipment compartment at the foot of the main display panel. This schedule has been adapted to the responsibilities assigned to each member of the staff. The spacecraft commander sits on the left (according to the practice on passenger aircraft), the cockpit pilot in the center and the lander pilot on his right. Even though everyone has a special area of ​​operation that they are responsible for. Everyone must know the spacecraft in all its parts and be able to perform every action.

 

The spacecraft is guided with the help of two integrated systems that provide information to the propulsion systems and the reaction rudder and the information display panels. These are the guidance and navigation systems and the stabilization and navigation system. Changing mode or speed is done using two short rotating handles, similar to the driving rod of an airplane. plus speed control knobs. The rotating handles allow sending roll, yaw and spin commands to the response rudder system. At the same time, they turn the engine in the desired direction, so that if the engine is running, a change in the flight path is obtained. Two indicators on the main display panel show the position of the spacecraft relative to fixed stars and can be used to determine position errors and rates of change.

The environmental control system creates a living environment for the astronauts during the flight. Under normal conditions the pressure in the command cabin is 1/3 atmospheric pressure when the atmosphere is a 100% nitrogen and oxygen mixture to reduce the risk of fire (see Apollo 7). The temperature ranges between 21-24 degrees. The system provides oxygen, hot and cold water from the 2CO disposal and odors from the control room and excess heat from the room and the equipment. Its operation is largely automatic. In the control panel of the command room 566 there are switches, 71 warning lights, 40 mechanical indicators and 24 other various devices.

The performance can be adjusted to several convenient modes depending on the tasks. They support the atmospheres during acceleration and deceleration, allow them to sit comfortably to perform their various jobs and reduce the shock of landing. For rest, two sleeping bags are used, a kind of hammocks that hang under the sheets. The number of sleeping bags comes from the thought that during the flight there will be one astronaut awake at any time. In practice it has been proven that it is possible and even desirable to allow all three to fall asleep at the same time.

The service compartment
The utility room is a circular structure whose base diameter is 3.91 meters, its length is 6.88 meters and its total weight is 24.95 tons. The service cabin is attached to the command cabin from the moment of launch until shortly before entering the atmosphere, it is discarded and burned up in the atmosphere. In this compartment is the spacecraft engine. The engine is mounted on an axle rack and provides 9300 kg of thrust. It is not possible to adjust the degree of its impulse, but it is possible to shut it down and restart it up to 50 times and for as short a time as 0.4 seconds. In total, it can be operated for 750 seconds. The extras are hyperbolic so no ignition system is needed. The width of the nozzle of the engine is 285 cm.
In the service compartment there are three fuel cells, each of which weighs 110 kg, one cell for hydrogen and two cells for oxygen (see changes in the structure of the spacecraft). These cells provide electric current to the command and service cells and also a certain amount of drinking water. The oxygen is also used by the environmental control system in the control room. Three silver-zinc batteries provide power to the command cell after separating the two cells from each other. Another tank in the service compartment contains helium gas at a pressure of 253 kg/cmXNUMX to feed the fuel and oxygen to the engine. The command cabin and the service cabin are operated using a reaction rudder system.
the moon lander
The lunar lander is designed to land on a celestial body that lacks an atmosphere and is therefore aerodynamically shapeless, however the lander is an extremely delicate vehicle. It is made of two layers of an outer aluminum wall with a thickness of one hundredth of a millimeter and an inner aluminum wall with a thickness of 1.5 millimeters. A light "blanket" made of 30 layers of a thin plastic membrane that isolates the vital parts from the immense cold and heat prevailing on the moon. The outer layer is made of a shiny material to return maximum radiation from the sun and thus prevent overheating. The lunar lander is made of two parts as the landing gear - the lower one and the ascent stage is the upper part.

The mechanism for connecting the command cabin to the lander
The two spacecraft are held by three tiny lugs. To strengthen the grip, a pump must be activated that attaches the two tools to the suction. Only in the final stage are a dozen strong brackets activated that complete the adhesion processes.

• A. Kneeling landing

The landing pad has a diameter of 4.29 meters, a height of 3.23 meters and a weight of 10.05 tons. It is a complex structure with 8 ribs and 4 folded legs when the lander is stored in the launch vehicle. Attached to each leg at the bottom is a plate with a diameter of 94 cm made of aluminum honeycomb. A ladder is attached to one of the legs. The role of the lander's engine is to slow down its speed and enable a soft landing on the moon. The engine develops a thrust force of 4,750 kg and can reduce it to 475 kg. It is possible to start it several times and tilt it in any direction by 6 degrees from its vertical axis to control the Alarod and Sabsov planes. In the landing area there are 4 cells:
Cabin number 1: special antenna for navigation for landing, electric batteries and spare batteries.
Cell number 2: electronic instruments of the landing radar, water tank and lunar research instruments.
Compartment number 3: electronic control system of the landing engine.
Cell number 4: Electronic system for separating the landing pad from the upper part. The landing pad serves as a launch pad for the upper part.

 

• B. The upper part

The upper part is used as a place to live for its two pilots and a launch vehicle from the moon in preparation for the connection with the command cabin. The diameter of this part is 4.29 meters, its height is 3.76 meters and its weight is 4.55 tons. The engine of this part has a simple structure in recognition of the importance of its critical role and is capable of developing a thrust force of 1600 kg. In this part there is a complex command panel, telescope, navigation system, adhesion radar, computer, 16 navigation engines 4 on each side, two triangular windows that allow a look down and forward and above the heads of the astronauts there are two observation portholes for the purpose of adhesion. In this part is also the exit opening. From the head of this part rise 6 antennae in three different shapes. There are no seats in this cabin and the astronauts sleep in it lying on the floor of the cabin and leaning on one of the sides. Since there is no gravity in the cabin, the astronauts attach themselves to the floor with flexible nylon belts that fasten them to the floor with a force of 12 kg.

 

Changes in the structure of the spacecraft

Advanced stages of the Apollo program and serious malfunctions during the flights and on the ground led to changes and improvements in the components of the spacecraft and they are:
A. Other changes after the Apollo 1 fire.

• 1 . The tragic death of the Apollo 1 pilots necessitated a change in the composition of the spacecraft's atmosphere from pure oxygen to a mixture of 60% oxygen and 40% nitrogen. The replacement of the atmosphere is to prevent the risk of ignition.
• 2. The mechanism for opening the door of the spacecraft was replaced with a new one, which opens in 3 seconds compared to 90 seconds in the previous mechanism.
• 3. Most flammable materials have been replaced with fire-resistant materials.
• 4. The outer nylon layer of the space suit was replaced with "Beta" fabric resistant to a temperature of 800 degrees.
• 5. These changes increased the weight of the spacecraft by 1,599 kg and necessitated a redesign of systems such as the parachute system.

b Changes following the flight of Apollo 13.

• 1. The number of oxygen tanks was increased from 3 to 4. The fourth is installed so that it is not connected to the three tanks.
• 2. The toilet compartment has an additional battery identical to those found in the lander.
• 3. The stock of drinking water (9 kg) was increased for emergencies.
• 4. In the control room, an electrical power plant was inserted with fuel cells that consume oxygen for the chemical reaction.
• 5. The Teflon sheath of the wires in the oxygen tanks was replaced with fire-resistant stainless steel. and before the pressure in the oxygen tanks (70 kg/mXNUMX).

To prevent accumulation in the tanks, consider putting in aerated tanks. Tests have shown that the movement of the spacecraft and the continuous removal of the oxygen from the tanks creates a sufficient mixing motion of the oxygen in the tank and its cooling. It was decided to give up the fan.
c Installing the "rover" lunar vehicle on the lander required increasing its weight to 17 tons and adding 900 kg to the command cabin and the toilet cabin.
The "Rover" Lunar Vehicle

To make it easier for the astronauts in their lunar work and to increase the work output, a special all-terrain vehicle called a "rover" was built. In accordance with the original Apollo program, the vehicle was made available to the last five teams in the Apollo program. The cuts in NASA's budget inevitably led to a reduction in the number of off-road vehicles. According to the new plan, only three vehicles were built.
The vehicle is 3.2 meters long, 1.8 meters wide and weighs 180 kg. The speed of the vehicle is 13 km/h. The range of operation is 50-60 km and it has a payload of 450 kg. For the purpose of storing the vehicle at the landing, it is built so that it can be folded to the dimensions of a stroller. After landing, the astronauts pull several rings. The vehicle slides to the ground and its four folded wheels straighten out.

The lunar rover is powered by two 36 volt silver-zinc batteries. The wheels are each equipped with their own motor. The vehicle's wheels are made of a mesh of steel wires instead of air-filled rubber. Titanium strips are installed on the surface of the mesh to limit its wear. The wheels are protected against "cracks". To prevent unexpected breakdowns, the vehicle is equipped with a toolbox.

The wheels and the shock brake system enable the passage of obstacles 30 cm high and trenches 60 cm deep. The lunar rover is able to climb a slope whose slope reaches 20 degrees. The vehicle's center of gravity is very low to prevent overturning while traveling on the hard surface of the moon. In case of falling from the vehicle, the astronauts fasten themselves with safety belts. The vehicle has a complex navigation system including a gyroscope, which provides information on direction, movement distance, speed and exact location. The rest of the indicators on the control panel allow monitoring of the condition of the batteries and other vital parts of the vehicle. The vehicle has television cameras and communication systems for the command room. The car has two rudder systems, a front system and a rear system. The rudders are in the form of levers similar to airplane rudders. All the materials from which the vehicle is built are highly reliable. They withstand large temperature differences, radiation and shocks involved in driving on unpaved terrain.

the space suits

The clothing changes during the different stages of the flight. There are three basic modes - no suits, space suits and suits for extra-vehicular activity, which are also used for extra-vehicular activity. During the flight, the astronauts wear a kind of thick harness, biological devices, a soft communication cap (the nickname given to him is Snoopy) with microphones and headphones, a porous lower garment, flight overalls and boots and he breathes freely. During the critical phases of the flight and during lunar activity or in space, the astronauts wear a suit for train activity. In the front part of the helmet - the window is coated with a special layer to prevent the accumulation of steam on it.

Apollo equipment included oxygen tanks and an emergency cooling system from the beginning. In the event of a malfunction, the main system releases an emergency oxygen purification system, a stream of cold oxygen passes through the suit giving an interval of 30 minutes for a quick retreat to the lander. This means loss of oxygen. A new arrangement put into operation from the Apollo 14 flight, not only solved this problem, but increased doing. A "reciprocal system" allows an astronaut to use his friend's cooling water in an emergency. Two flexible tubes that allow for contact in case of need were included in the equipment carried on these flights and thus the oxygen was released from the cooling role. The current of the oxygen purification system was enough for an hour and a quarter and return from a more distant place. A container of water and orange juice is attached to the helmet to allow the astronaut the necessary refreshment during tedious work.

The Moon Shipyard

The Apollo spacecraft and launch vehicles were produced in different factories. A huge facility was built for their assembly, which is 160 meters high, 219 meters long and 158 meters wide. The building was built of stainless steel and special plastic materials. Because in this area, California, very strong winds blow - hurricanes, it was built so that it could withstand wind speeds of 200 - 300 km/h. Its tolerance is 30 cm. That is, he can swing to the sides at a rate of 30 cm without collapsing. For comparison, the tolerance range of Migdal Shalom in Tel Aviv is 5 cm per side.

The building has two parts. One part is used to store the electronic control facilities needed to assemble the launch vehicles and spacecraft. In the second part of the building there are four assembly units so that four spaceships can be assembled in them at the same time. The building has four doors on its sides, 21 high-speed elevators, CCTV and various means of communication and a fan system. At a height of 150 meters on the wall of the building is an observation room made of glass for 200 journalists and 50 very important people (VIP).

After the launch vehicle is assembled, it is surrounded by many platforms, a kind of scaffolding, one above the other, so that a person standing on one of them sees a 10-meter section of the launch vehicle. The technicians stand on these surfaces when they are engaged in assembling the launch vehicle and testing its systems.

The assembly of the launch vehicle

At the end of their production, the various stages of the launch vehicle are sent to the main center for space flights in Huntsville, Alabama, where they are rigorously inspected, each part separately, and then sent to the lunar shipyard. The first stage and the second stage, due to their size, are sent through bodies of water only. through the Tennessee and Missouri rivers to the Gulf of Mexico. From there by inland waterways they reach the Banana River at Cape Kennedy and through a canal dug especially for this purpose, they reach the shipyard building. The third stage, which is the smallest, is sent through the air in a Super Guppy - a sophisticated stratospheric plane that is made especially for transporting launchers. Massive mechanical vehicles bring the launcher stages into the shipyard.

The assembly is done using large cranes that hang and descend from the roof of the building and are able to move back and forth along the length of the building. Until the Apollo flights, launchers were assembled horizontally and then propped up. Here the launcher is mounted vertically. The cranes carry the launcher stages and stack them on top of each other. Eight lower bays are on one side of the building for testing and preparation of the launcher's smaller upper stages and its instrumentation and guidance units.

After the assembly is installed in the launcher its electrical system, it undergoes a very thorough inspection for four weeks and only finally is the Apollo spacecraft assembled in its nose. The assembly facilities, in addition to their main function, also allow compatibility tests between the various stages of the launcher to the spacecraft and between the launcher and the array of ground auxiliary equipment. Thanks to this building and its facilities, the space scientists and engineers at Cape Kennedy can assemble the launcher in 14 weeks from the time its parts arrive until it is launched.

the caterpillar

After the launcher and spacecraft are assembled, they are transferred to the launch pad on a crawler. It is a vessel with eight sets of caterpillars carrying a surface measuring 35 by 40 meters and six meters high. The weight of the vehicle is 2700 tons and it is capable of carrying a load of 6,000 tons. The speed of the vehicle is 2.5 km/h.

The caterpillar carries its launcher and umbilical tower. The tower carries the refueling pipes, pressure and electrical voltage of the various stages of the launcher until it is lifted off. Nine bridging arms. On the gap of 20 meters between the launcher and the control tower. In the upper arm there is a small cell called the white cell (due to the white color of the technicians' coats) that attaches to the opening of the spacecraft's command cell. On top of this arm, the astronauts arrive at the cabin and make the final preparations for launch. Two elevators serve the control tower.
The surface of the crawler serves as a launch pad for the launcher. There were quite a few concerns about his fate at the time of launch. The space agency's engineers feared that the damage caused to the crawler during the launch would be extensive. It was estimated that it would take two to six weeks from the moment of launch until the preparation of the pedestal for reuse. With the launch of the first spaceship it became clear that the damage was not great. A total of 12 days were required until the caterpillar was trained for reuse.

The journey is therefore the launch

After assembling the launcher and spacecraft, the crawler enters the space shipyard, crawls under the surface on which the launcher is placed and slowly rises with the help of a hydraulic system and begins the 5.5 km journey towards the launch pad. Special stabilizers balance the launcher so that it does not tilt more than 4 degrees to the right or left during the journey. The dangerous section is towards the end when the vehicle has to overcome a 3 degree slope when it goes up the launch pad.

A special road was paved for the crawler so that it could withstand the heavy load. The width of the road is 40 meters and the depth of its infrastructure is 21 meters. The infrastructure is filled with massive rocks on which a layer of pressed concrete was poured and a layer of rock dust mixed with concrete was spread over it. To reduce the friction created by the steel caterpillars, the road ahead is sprayed with 100 tons of soap spray to make it smooth.

At the end of its path the crawler arrives therefore the launch. The pedestal itself is built of concrete at the mouth of a small valley, so that the ascent on one side is not steep while on the other side there is a deep chasm. Yes, the launch itself is bisected by a chute into which the flames emitted when the engines are ignited flow. Here, next to the launch pad, the hydraulic arms of the launcher slowly lower the surface of the launcher until it settles on top of the pad. With the stabilization of the pedestal, the caterpillar comes out.

Yes, the launch itself is in the northern part of Merritt Island. The reason for the pedestal being near the sea is the huge amounts of water needed to suffocate the flames and reduce the destruction caused by the launcher during the launch. This saved hundreds of millions of dollars.

communication system
A complex and sophisticated communication system was made available to the Apollo program and it provided means for voice communication, television, telemetry, routing and measuring distances between the spacecraft and the earth, between the command cabin in lunar orbit and the lander standing on the moon and the lander for the astronauts when they leave it for the earth.

The connection with the Earth takes place through a network of 14 stations spread over the Earth. These stations had antennas with a diameter of 9 meters and provided continuous coverage from horizon to horizon when the spacecraft was in terrestrial orbit. The network was completed by surveillance ships and aircraft. As the spaceship moves away from Earth, the restrictions associated with the horizon disappear. At such great distances, communication is maintained by three ground tracking stations with antennas 26 meters in diameter. One in Goldstone in California, the second in Madrid in Spain and the third in Canberra in Australia. Each of the three stations was connected to the Manned Flight Center in Houston, Texas and the Goddard Space Flight Center in Grunblatt, Maryland through land lines, submarine cables, wireless communication and communication satellites and maintained continuous contact with them.
Additional chapters in the history of space exploration series:

• Mercury program
• Gemini plan
• Voskhud plan
• Vostok program
• Russian exploration of Mars in the sixties and seventies

The Apollo manned flight series

• Apollo 11
• Apollo 12
• Apollo 13
• Apollo 14
• Apollo 15
• Apollo 16
• Apollo 17
• Apollo-Soyuz flight