Hayadan > Apollo 15 - erecting a monument in memory of the astronauts and cosmonauts who were killed in the line of duty, and illustrating Newton's laws

Apollo 15 - erecting a monument in memory of the astronauts and cosmonauts who were killed in the line of duty, and illustrating Newton's laws

The deaths of Dobrobolsky, Volkov, and Soyuz 11 pilots Petsaib did not deter the US space agency from launching Apollo 15 to the moon despite the many dangers involved in the flight of the Apollo 15 crew that included David Scott, James Irwin, and Alfred Worden. Two of them, David Scott and James Irwin, were chosen to land on the eastern "shore" of the Sea of Rain near the ridges of the Apennine Mountains. The command cabin was named Endeavor after James Cook's research ship and the lander was named Falcon.

The Apennines are extremely high mountains and rise to a height of 3.5 km. As with the Apollo 14 flight, so too this time the space scientists hoped to collect initial soil samples. The hypotheses that the geologists had were that the Apennines were the most exposed rocky material on the moon. Therefore, this time it is possible to gather the most information about the structure and internal composition of the moon. Near the Apennines is the Hadley Canyon. This canyon resembles a long and narrow river that stretches for 100 km and is 360 meters deep. Two hypotheses have been put forward regarding the nature of this mall. One hypothesis says that water flowed in this place. On the other hand, the second hypothesis says that it was a path of hot lava. The Apollo 15 pilots were tasked with exploring this mysterious place as well and taking soil samples from the rim of the canyon. Landing near the mall was dangerous. Errors in the landing computer may result in landing inside the mall without being able to leave it.

North of the landing site are a number of deep and large potholes which may have had a lava flow. This area is called the "North Complex" and it was included in the studies that were assigned to the Apollo 15 pilots.

Much of the work assigned to David Scott and James Irwin included chemical measurements of the lunar soil, its gravity and magnetic field. The internal structure is an atmosphere if there is one, the solar wind, the moon dust, the emission of heat from the moon, etc. This work program was designed for 20 hours when it is divided into 3. Two parts each 7 hours and one part 6 hours. The work is carried out while walking and traveling in a special "rover" vehicle that is attached to a lunar flight for the first time. 67 hours of the flight were spent on the moon. In total, the astronauts had to travel 35 km and collect 80 kg of soil samples. In order to carry out their duties, they were equipped with 600 kg of scientific equipment. The equipment carried by the spacecraft was more sophisticated than its predecessors and included:
1. A lunar TV camera that can be directed and monitored remotely. Two engineers in the control center can rotate the camera, point it up and down and focus it so you can shoot up close.
2. Cameras and scientific instruments located on the wall of the toilet cabin that remained together with the command cabin in orbit around the moon after the lander was separated from the command cabin.

A. A panoramic camera containing more than 2.2. Km of 12.5 cm wide photographic film. This amount is intended for 1350 photographs, each of which covers a rectangular area 292.6 km long and 20.8 km wide. The resolution of the camera is 2 meters.
B. Mapping camera - this camera contains a roll of film 63 meters long and 12.5 cm wide for 3000 photographs. Each photograph covers an area of 168 km. The cameras were required for geochemical mapping of 20% of the lunar surface.
third. Star camera - this camera automatically photographs the sky whenever the mapping camera photographs the moon by checking the position of the stars. In these photographs, the scientists could determine exactly the position of the moon and the location of the area captured by the mapping camera.
d. In coordination with the mapping camera, a laser device operates that measures the exact distance between the spacecraft and the moon at every moment when a certain photograph is taken. The measurement results are immediately printed on the appropriate film section.
A large computer located in the control center, Houston, then merges all the data and analyzes the material extracted from the cameras, the laser device and the information accumulated in tracking stations on Earth. Based on this information, the computer determines the path of the moon's orbit, the orbit of the spacecraft and the exact location of prominent sites on the moon.
God. Four spectrometers to measure radiation to study the composition of the lunar surface and its environment. 2 spectrometers work on X-rays. The return of the radiation varies according to the composition of the soil and based on these it is possible to calculate the relative amounts of silicon and magnesium over large areas on both sides of the moon.
and. The concentration of radiation-emitting substances on the moon is diagnosed and measured using an alpha particle spectrometer and a gamma radiation spectrometer. To reduce the possibility of data distortion by gases emitted from the spacecraft, the instruments were placed on a 25-meter-long collapsible pole adjacent to the service cabin placed far from the gases emitted from the engine.
G. Two X-ray telescopes for measuring pulsars. These devices were operated by Worden when he orbited the moon alone and jointly with his companions Scott and Irwin after they lifted off from the moon and connected with the command cabin.

These devices were operated by Worden when he orbited the moon alone and jointly with his companions Scott and Irwin after they lifted off from the moon and connected with the command cabin. The maps produced by these instruments after the flight graphically presented the following data:

Geographical data with the exact dimensions of the craters, the hills, the mountain ranges, the ravines and the gravel fields. Geological and chemical characterization of the lunar surface and the layer below them - how much uranium, thorium and potassium are in the lunar rocks. The magnetic properties of the moon's surface, the layers below it and the space above it. Atomic particles and gases in the lunar space.

The exploration of the moon was also carried out using radio waves. The astronauts transmitted 2 radio waves at the same time, one to the Earth and the other to the Moon. By measuring the changes in the return of the radio waves to Earth, the researchers hoped to learn about electrical properties, the degree of roughness of the moon's surface and other facts about it.
The researchers estimated that between the sun and the earth and between the moon and the earth, there are areas where the gravitational forces of these celestial bodies cancel each other out so that star dust and other materials remain "stuck" in these areas. It has been suggested that the rays of the sun reflected from these materials are the cause of the mysterious light that appears between the earth and the sun and is called "Gaganshein". The astronauts were tasked with photographing this phenomenon.
In this flight, a new communication method was used that allows contact with the astronauts even when they are moving away from the lander and it is not in their field of vision. The astronauts' helmets were equipped with a special preparation that prevents the formation of vapors that have the power to limit the field of vision. This preparation is effective for 5 hours, it is cheap, non-toxic and non-flammable. The death of the Soyuz 11 pilots resulted in a last-minute regulation change before takeoff. Astronauts must wear their spacesuits when they lift off from the surface of the moon and when they enter the atmosphere on their way home.
Before the flight, the Apollo 15 pilots were put into a 20-day isolation period and on July 9.7.1971, 4, a satellite was launched to measure the solar radiation to make sure that there was no danger to the astronauts' lives from the solar wind. There was also no lack of glitches leading up to the launch. The launch tower was struck 15 times by lightning and ground equipment was damaged. Magnesium chips were discovered in the spacecraft's batteries. The huge life belts designed to help lift the astronauts from the ocean were sabotaged. These faults were corrected and did not cause disruptions in the schedule or the postponement of the launch. Apollo 26.7.1971 was launched on July XNUMX, XNUMX.

26.7 - the first day of the flight

On July 26.7, Apollo 15 set off. 12 minutes after launch, the spacecraft entered Earth orbit at an altitude of 167 km. 3 hours later, it turned its bow to the lunar flight path, detached itself from the orbit and began its journey to the moon. The attachment maneuver with the landing went very successfully without any problems. The spacecraft reached escape velocity 2-3 seconds ahead of time.

Three more hours later, a fault was discovered. Two warning lights were lit in Houston - the control center and the spacecraft's command cabin. These signals showed that the engine was running without an instruction from the computer. It means a short in the control system of the valves leading fuel to the engine. From the tests that were done, it became clear that the lights came on because of a defect in the circuit breakers only. During take off, Irwin's heart rate increased.
27.7 - the second day of the flight

After sleeping for 8 hours and 20 minutes, the Apollo 15 pilots woke up and turned on their spacecraft's engine for just one second. This activation was necessary for a slight correction in the flight path. With the successful activation of the engine, the fear for the fate of the flight was removed. The malfunction that occurred in the circuit breaker on the day of the launch raised concerns that there might still be a malfunction in the control system of the fuel valves. As a result, concern arose for the fate of the moon landing. As mentioned, the fear of the astronauts and space scientists for the future of the landing was dispelled and permission was given to continue the flight.
The fault in the circuit breaker was known before the flight. X-ray tests on the circuit breaker revealed suspicious wires. Despite this, it was decided to launch the spacecraft. In the worst case, the valves were activated manually. The engine was started an hour ahead of time. The successful operation of the engine created a situation of a difference of - 15 cm per second from the desired speed. This difference allowed the cancellation of two path corrections later in the flight.

While the astronauts were resting, the spacecraft was put into a slow rotational movement around itself to regulate the heat and light it receives from the sun. The rotation speed of the spacecraft was 3 times per hour.

What it is from the spirit of the times can be learned from the message of US President Richard Nixon to the astronauts who woke up from sleep: "Apollo 15 is advancing safely to the moon and man is on his way to another step beyond the threshold of the sky. Man always looked up at the sky with low spirits. But he also looked at them with curiosity and courage until they overcame the laws of nature and pulled man beyond gravity, beyond his fears, into his dream, to his destiny."
28.7 - the third day of the flight
David Scott and James Irwin moved to the lander to check it out. The protective glass of the altimeter was found broken with its pieces rolling on the cabin floor. The glass fragments were removed using a vacuum cleaner. After that, a comprehensive test was conducted in the cell while it was broadcast on TV. The lander was found to be intact and its pilots transferred electronic equipment to it in preparation for landing on the moon. The smooth flight of the spacecraft allowed an allowance of 70 extra minutes for sleep. An electrical fault caused the internal lights to turn off in several devices, but it was quickly repaired.
29.7 - The fourth day of the flight
Scott and Irwin conducted a two-hour inspection of the lander and found it to be in good condition returned to the command cabin. Here a small and unpleasant surprise awaited them and their friend Warden. The astronauts' suit was flooded with water due to a leak. The water seeped behind the control panel. Two proposals were made to stop the leak but they did not help. Finally Scott got a wrench out of the toolbox and tightened the connection that had come loose in the chlorination system. The astronauts still had time to get wet until the leak was repaired. In the event of a temporary shutdown of the water supply, the astronauts filled a bucket with water from the drinking water pipe. After the repairs, they fell asleep for several hours. They needed rest for their entry into lunar orbit.
81/100 of a second were required for the spacecraft's engine to put it into lunar orbit. This operation of the engine was carried out according to a new method. Apollo 15 circled the moon in an elliptical orbit that is 83-270 km from the ground. The engine was turned on when the spacecraft was on the hidden side of the moon and therefore contact at that time with Houston was cut off. According to a new method, contact with the spacecraft was renewed 24 minutes later and not 36 minutes like previous flights.
Upon entering orbit, the astronauts described the appearance of the moon. Scott said that "it's really confusing, it's hard for the brain's computer to sort everything"

Later he described vast expanses of a gray landscape, full of craters whose inner walls are white, and Scott also told of an area that appears to be a large desert and can be seen in dust storms and in the wake of a vortex of dust after the storm. The pilots of Apollo 15 continued the research of their colleagues for the previous flight - Apollo 14 in the essence of the mysterious flashes. In the tests they conducted for an hour, they noticed 54 flashes.
30.7 - the fifth day of the flight
Before landing on the moon, the spacecraft's engine was turned on for the second time to reduce the flight altitude. The orbit of the spaceship was now 17.5 - 103 km. Changing the flight path is done on the hidden side of the moon. Erwin and Scott then fell asleep for several hours. After waking up from sleep, they put on the space suits, entered the lander and tested it intensively for 3 hours. In the 12th lap, the lander pilots prepared for disconnection from the command cabin on the hidden side of the moon. The first attempt was unsuccessful. The disconnection failure was caused by a plug that was not inserted sufficiently and as a result the power system was disconnected from the separation system. Warden the cockpit pilot pushed the plug into place. After power was restored in the separation system, Scott pressed the button and the lander was successfully disconnected from the control room. The disconnection of the two spaceships from each other was done 25 minutes late.

For an hour and a half the two spacecraft circled the moon together side by side. At the end of the joint lap Warden raised the cockpit to a higher orbit. The distances of the command cabin from the ground were 120-100 km. An hour later on July 31.7, the lander's feet touched the ground of the moon. Warden, who was left alone in the control room, had no shortage of work either. He was engaged in photographing and investigating the moon with the help of the instruments that were in the spacecraft.

Worden was under strict medical surveillance. He was the first person tasked with orbiting the moon for 6 consecutive days. The space doctors were interested in knowing the effect of the prolonged stay in lunar orbit on the physiological functions of the human body, body organs and blood circulation. These issues arose after the Apollo 14 flight. In this flight, Stewart's heart muscle function decreased while he orbited the moon alone. In contrast, with Shepherd and Mitchell who worked on the moon, at that time the changes were minimal.
31.7 - the sixth day of the flight, the first day on the moon
Despite the 25 minute delay caused by the failed attempt at the first disconnection, the spacecraft landed 8 seconds late and when it missed the target by only 450 meters. The landing was 450 meters northeast of the landing site. At a height of 30 meters from the ground, Scott reported clouds of dust preventing eye contact with the ground. The landing was performed blindly as per command under instrument control only. Warden in the control room passed over the lander but could not see it.
20 minutes after the landing, Scott opened a porthole in the ceiling of the lander and for half an hour gave Houston a detailed report on the landscape at the landing site. Scott described the place as smooth and flat. At a distance of 20 meters he noticed several fresh rocks and at a distance of 60 meters an old rock. He also did not forget to give names to several craters. One crater was named Soliot in memory of Dobrobolsky, Volkov and Patasiev, Soyuz 11 pilots who tragically perished while returning to Israel. Another crater is called St. George after the wine Zoe St. George that the heroes of Jules Warren's book drank while looking for the moon.
The excitement Scott and Irwin found themselves in as they watched the scenery reflected from the windows prevented them from falling asleep easily. They had to sleep for 7 and a half hours. A malfunction in the lander's oxygen system forced them to get up from their sleep an hour and a half early. The leak was in the urine valve in the tube leading from their spacesuits to the outer side of the cell. The valve closed and the pressure in the chamber returned to normal. It was suggested to the astronauts to sleep for another half hour. Scott and Irwin preferred to stay awake to prepare for their first tour. In total, the lander lost 4 km of oxygen out of the 43 kg it had.

Scott went out first followed by Irwin. The first actions they performed upon leaving the lander included a quick collection of soil samples, in case they had to return to the lander and leave the moon. Scott placed a color TV camera a few tens of meters away from the lander. The photographs taken on Earth were of the highest quality. They can be distinguished in every detail.
Scott and Irwin had difficulty removing the "Rover" travel vehicle from its storage place on the side of the lander. At one point the vehicle got stuck and they had to forcibly remove it from its place. When it was released, difficulties were discovered in its operation. In the first moments they had to push him with their hands. A malfunction in the front steering system and the electrical system forced the astronauts to drive its rear wheels. As a result, the speed of the "rover" was reduced to 10 km/h.

While sitting on the big wheels that splashed around moon dust, Scott Hish quickly got used to driving the "Rover". This is evidenced by the following conversation between him and his colleague Irwin:

"Listen man, that's called a ride" shouted Scott and continued "Oh, this is really a sports driving course, listen, man, listen, this is a real car competition".
"Hold on tight" Scott warned Irwin "I'm going to zig zag a bit here"
Irwin replied: "We need seat belts, don't we? It's really a raging mule"
Scott: "It really is a ride of jolts and bumps, isn't it? I have never been on a trip like this before."
After a while Scott called out: "Look how this baby climbs the hill".
Irwin reported: "We travel at an average speed of about 8 km/h...when I have to make a sharp turn, I can do it well."
At another stage of the ride, Scott called to Irwin: "Oh, look back there, Jim, or look at that, isn't that something?" We are on a slope and we are looking back into the valley."
Erwin: "It's incredibly beautiful."
Scott: "That's great"
Erwin: "It's unreal, it's the most beautiful thing I've ever seen in my life."
On their first trip, Scott and Irwin traveled 8 km collecting soil samples and taking photographs while passing by the Apennine ridges, several craters and the Hadley Canyon - the journey to the canyon took two and a quarter hours. And according to their words, in the photographs, the Apennine Mountains appear in the foreground as huge and rounded hills very similar to the ski slopes of the "Valley of the Sun" in the state of Idaho in the USA. When the camera was pointed north the crater seemed to be a pair of giant snowdrifts stacked against each other in the lunar landscape.
Scott and Irwin discovered that the two sides of the Hadley Channel are not alike. On one side of the channel, large pointed rock blocks are scattered, while on the other side there are no large rocks. The channel is very steep on one side and has a slight slope on the other side. On the sides of the channel, layers are clearly visible from which much can be learned about the formation of the moon.

Scott and Irwin inspected the elbow crater and took soil samples from it. This is the only crater formed on the side of Hadley Canyon. The researchers assumed that they would find rocks blown from the depths of the canyon. Irwin fell out of the vehicle twice while driving. The last 90 minutes of the tour were made near the lander and were dedicated to placing instruments and drilling. The devices placed are:

A passive seismograph for measuring earthquakes and shocks created when meteorites hit the lunar surface.
Magnetometer for measuring the magnetic field of the moon - the very existence of a magnetic field was a surprise to the researchers. This device also measures other magnetic phenomena that change noticeably with time and can be attributed to electromagnetic particles passing by the surface of the moon. The magnetometer is able to measure changes in intensity. in the frequency and direction of the magnetic field using sensitive measuring devices placed on 3 poles fixed in different directions.
A spectrometer for measuring the streams of gases from the sun to determine the effect of the flow of particles coming from the sun.
A large reflector for more accurate measurement of the distances between the Earth and the Moon.
A device for measuring the solar wind - a thin aluminum plate is spread over the surface of the moon and collects the particles of the solar wind that hit it. Before taking off from the moon, the board was returned to the lander.
A nuclear power and transmission station was placed on the moon to operate the measuring devices. In the reactor of the station is the radioisotope plutonium 238. The radioactive decay creates heat that turns into electrical power with a power of W70.

Various measurements and observations were conducted on this tour and the following two tours using mobile devices:
1. Gnomon - this device contains a special vertical for marking units of length and surfaces painted for comparison in black, white and various intermediate degrees of gray, green and red.
2. Pantometer for soil strength measurements.

Observations and experiments were carried out to determine the mechanical properties of the lunar soil, a qualitative assessment of the amount of dust rising from the surface of the moon during the landing and takeoff and during the journey in the "rover" and the depth to which the astronauts' feet sank while walking.
Scott had to drill 3 holes 3 meters deep. Due to difficulties in drilling and fatigue, he reached a depth of 1.5 meters and the continuation of drilling was postponed until the second tour. The drilling program included two drillings at a distance of 10 meters from each other into which tiny electronic thermometers with high sensitivity are lowered. These devices connected to the central data transmitter must operate for a year and transmit to Israel data on the rate of heat flow from the moon to the surface and on the thermal conduction of the material of which the moon is composed. The third drilling was done with a hollow drill which had to absorb crumbled rock and sand into it.

Scott and Irwin toured the moon for 6 hours 34 minutes and 14 seconds, about half an hour less than planned. The shortening of the tour was due to overexertion and consumption of oxygen by 17% more than planned. On their way to the landing, they collapsed more than once and were seen on the television broadcasts as falling due to fatigue. Even their moans were heard. When they entered the landing, they discovered a water leak at the rate of 11 liters. The fault has been fixed. Scott complained of pain in his fingers. Both claimed that the skin on their fingers was worn away due to the constant rubbing inside the special protective gloves. The pungent smell of the soil samples did not prevent them from falling asleep. Scott and Irwin were two hours late.

1.8 - The seventh day of flight, the second day on the moon
Scott and Irwin had slept 16 hours when they woke up and worked for two hours preparing for their second tour, eating and cleaning the cabin floor from a puddle of water. But a serious malfunction was discovered in Scott's survival system (in the space suit) and the astronauts left the landing an hour and a half later. It turned out that there was an air bubble floating in Scott's spacesuit. The problem was solved by spraying the water in the space suit loading, just like air is sprayed from the braking system of a car.

The first action that the lander pilots performed when they left for their second tour was to repair the "rover". Space technicians discovered that the forward steering had malfunctioned when the front wheels closed. After the fault was fixed Scott activated the front and rear steering only. This driving was not to his liking - the vehicle moved like a crab. Because of this Scott continued to drive it, running one system. This time the speed of the vehicle reached 13 km/h.

The second tour was done in the Apennines and lasted 7 hours and 12 minutes. The utilization of oxygen was reasonable and a sufficient amount remained in the tanks. The "Rover". Made a road of 14 km. On his way, the astronauts stopped by the "orientation egg". This journey was longer than the first. On their walking tour, Scott climbed a rock on one of the hills to take a picture of Irwin digging, but he fell. Irwin came to help him to his feet. It was feared that Scott's heartbeat was increasing and he was therefore advised not to overexert himself. A few minutes later it became clear that Scott's heart was working properly. The source of the fear stemmed from a malfunction in the device that checks his heartbeat.

The soil samples this time included rocks the size of footballs. One of the stones looked green. When they lifted their helmets they realized that the color of the stone was light gray. The culmination of the tour was reflected in a metamorphic rock that was found near the spur crater. The crystallization testified that the origin of the rock is in the lunar condenser. This rock ignited hope among geologists. They expected to find in this stone the secret of the creation of the solar system. All the rocks collected by the astronauts include rocks of mountain origin, covered in dust. In one of the places, Scott discovered a light green sandy layer.

Sometimes the astronauts skipped like kangaroos as they moved around the rocks and dust samples they collected. Other times, they ran backwards out of craters or shallow potholes they had dug and jumped towards the vehicle to place their finds in it.

The landscape changed frequently - a rounded mountain range, dusty plains, groups of craters. All these constituted a rare television display from space. The shots were better than the shots taken on the first day. This time the sun was higher and thus the activity of the camera lenses was preserved.

On their way back to the lander, Scott increased the speed of the abandoned vehicle and jumped over the small stones along the way. The seismograph picked up the rumble of the lunar vehicle's thick wheels. When they returned to the lander, Scott continued the drilling he had started the previous day and had not finished. This time use a special drill. He did manage to deepen the excavation and insert another part of the device for measuring underground temperatures, but the drill bent several times.
In another drill in which the two astronauts took part, Scott reported that the walls of his trench were smooth and very thick. He found small white pieces and at a depth of 30 cm he found harder ground, but this did not prevent him from reaching the bedrock. Scott used a drill to insert several more fixtures into the borehole and Irwin measured the vehicle's wheel tracks on the lunar soil.

The last actions before entering the lander included transferring the findings into it and raising the US flag. At the end of their activity, Scott and Irwin entered the lander, made preparations for their third tour and fell asleep.

2.8 - the eighth day of the flight, the third day on the moon
After sleeping longer than planned, Scott and Irwin continued the drilling work. These drillings caused certain difficulties which caused a delay in the schedule. At first they couldn't pull out the pipes stuck in the ground. When they managed to overcome this problem, it became clear that the partial joint device of the pipeline was not working. With great difficulty, Dr. Allen, the contact person, managed to convince them to continue their work. And indeed when Scott and Irwin took out a soil sample from a depth of 2.8 meters their mood improved.

At the end of the drilling operation, Scott and Irwin boarded their vehicle and made their last journey. In this journey, they covered a distance of 8 km in a time of 4 hours and 50 minutes. The journey was conducted along the Apennines while stopping at several craters including the Scarp Crater. In the center of the crater they found crumbling dirt made of tempered glass of various sizes.

The astronauts' lot of activity tired them out a lot. This will be evidenced by Scott's testimony on a large rock. Scott fell flat on his face near Hadley Gorge and rolled several meters down a slope. The camera also fell from his hand. Irwin came to his aid, but Scott managed to get up on his own. On their way back they checked the regolith.

At the end of their tour, Scott opened a post office on the moon when he affixed two stamps with a face value of 8 cents each, dedicated to US achievements in space. Irwin gave a short speech about the first postal service in space and after his speech stamped the stamps in a special facility. The rover was positioned 100 meters from the lander and its camera was pointed from the ground later to film the liftoff. Before they entered the landing, Irwin said a number of verses from the Psalms.

Scott proved in a tangible way that Galileo's theory that bodies of different shapes and weights thrown towards the ground will arrive there at the same time is correct. In one hand Scott held a hammer and in the other hand at the same height he held a falcon feather. He threw the two bodies and indeed they reached the ground together. Worden, who was left alone in the command cabin, reported the discovery of dust peaks on the moon that may serve as proof of the emission of gases from the inner layers.

After a stay of 66 hours and 55 minutes on the moon with about 80 kg of soil samples from the oldest and possibly the first in the moon rocks and scientific information which is also extremely important, Scott and Irwin took off towards connecting with the command cabin. The take-off was made when in the background the sound register of the American Air Force's anthem emanates: "We soar to the expanses of the wild azure". There was a fear that they would carry dust particles and blur the rover's camera lenses, but nothing happened.

8 minutes after takeoff, the lander entered lunar orbit. After another 10 minutes, Scott noticed the Endeavor - the control room. An hour and a half after takeoff, the lander and the control cabin were attached. The connection was filmed from the command center and broadcast to Israel. The first action performed by the Apollo 15 pilots was to transfer the soil samples and scientific information to the command room. After that they also moved to the control room. In the three tours on the lunar surface, Scott and Irwin moved no more than 8 km from the lander. Astronomers at the observatory near the University of Texas managed to direct a laser beam at the reflector left by the Apollo 15 crew on the moon.

The space agency's operations department doctors expressed their admiration for the astronauts' ability to adapt to the physical conditions prevailing on the moon. The doctors observed a gradual and rapid improvement in the way the astronauts walked on the moon. In order to reduce as much as possible the width and height of their jumps, Scott and Irwin studied except for the movements of their knee joints and directed their strides mainly with the help of their ankle joints and feet. As their tours on the moon continued, their physical condition improved and their oxygen consumption decreased.

Scott and Irwin left a small monument on the moon in memory of 14 American and Russian astronauts who fell in the line of duty. The monument is made of a simple metal tablet made of silver and black colors and is placed inside a small volcanic crater. The names of the astronauts who perished are engraved on the table. Next to the table they placed a shiny metal figurine, representing a fallen astronaut.

3.8 - the ninth day of the flight

An oxygen leak in the tunnel connecting the two spacecraft led to a two-hour delay in disconnecting the lander from the command cabin. The astronauts had to make another lap of the moon to fix the leak. After disconnection the lander intended to crash on the lunar surface. The echoes of the crash (about 85 km from the landing site) were picked up by the seismographs placed by the pilots of Apollo 12, Apollo 14 and Apollo 15 for an hour.

After disconnecting the lander, the astronauts took "Suconal" pills and fell asleep for 10 hours. Before going to sleep, Irwin activated the bio-medical devices to report the state of his sleep. When they woke up, the astronauts continued their experiments and photographing the surface of the moon. They also examined the causes of slight deviations caused by spacecraft in lunar orbit. 20% of the panoramic photos were broken and several devices were out of order. In researching the nature of the flashes of light, Worden covered his eyes with a special shield and nevertheless saw them.

4.8 - the tenth day of the flight
After sleeping for several hours, the astronauts continued exploring and photographing the moon. They tried in vain several times to photograph the Russian lunar rover Lonkhod 1. On the 74th lap a slight change in trajectory was made to ensure a safer path for the satellite that Worden then launched from the spacecraft to orbit the moon for a year. At the end of the 74th lap on the hidden side of the moon, the spacecraft's engine was activated, it was taken out of its orbit and transferred to a terrestrial flight path.

The structure of the satellite
The satellite that Worden launched has a hexagonal shape, is 78 cm long, 35 cm wide and weighs 36 kg. The satellite contains a radio transmitter to operate devices and transmit data to Earth. Control unit, accumulators and solar batteries.
The role of the satellite was to study the structure of the lunar soil, measure its magnetic field and measure cosmic particles. A certain amount of the particles is absorbed by the lunar soil. Using this satellite, the researchers wanted to make a comparison with the sun and other celestial bodies. The researchers hoped to find the origin of these particles.
5.8 - the eleventh day of the flight
The highlight of the day were two scientific operations. One is observations of X stars - pulsars and the other. Worden's non-rail activity. The observations aimed at the pulsars were made jointly with Tel Aviv University. The choice of Israel was due to the fact that Israel (apart from the USSR) was, at the time of the experiment, the only place on earth where darkness prevailed. The measurements were conducted simultaneously in the spacecraft and at Tel Aviv University. The experiments in the spacecraft were done using 2 X-ray telescopes and at Tel Aviv University using the telescope at Mitzpe Ramon. The data obtained from the two experiments were later used to compare the results in a study of X-rays from space. In the second operation Warden exited the spaceship towards the toilet compartment where the scientific instruments were. His activity outside the train lasted 20 minutes. as planned. He was allotted 60 minutes in case of unexpected breakdowns. There were 3 actions. The first time Warden returned photographic films to the command room, the second time he inserted new films and the third time he performed tests on the measuring devices.
In order to help Vardon in his work, Irwin stood so that half of his upper body was outside the spaceship and Vardon was attached to an 8 meter long rope and advanced towards the devices using a special handrail which was used for him to hold on. All the while Scott was driving the spaceship. The three astronauts wore the spacesuits during Worden's hover. There was slight concern in Houston when Worden's first steps outside the spaceship were not seen on television. A few seconds later the picture cleared up. The rope to which Wardon was tied to the spacecraft was a good means of repairs outside the spacecraft. In case of malfunctions such as the malfunction that happened on the Apollo 13 flight. At the end of this activity the astronauts slept for several hours.
6.8 - today is the twelfth day for the flight
The astronauts photographed the lunar eclipse that occurred at the time. They held a half-hour press conference and returned to photograph the eclipse. Photographs of the lunar eclipse were not possible due to the breakdown of the "rover" camera the previous day. Scott said about the eclipse: "The moon changes and goes from a very pale orange color to a deep orange color on one side with a gradual change."
7.8 - the thirteenth day of the flight
Scott, Irwin Wardon slept and then prepared for landing. The engine was started for one second to make a minor correction to the flight path. The spacecraft landed 500 km north of the Hawaiian Islands. The landing was somewhat heavier than usual. The leakage of sodium tetroxide (4O 2 N) ate the sheath of one of the parachutes and it did not deploy fully. This malfunction did not prevent a successful landing of the spacecraft.
Apollo 15 stayed in space for 12 days, 8 hours and 12 minutes. As during the takeoff, so also during the penetration into the atmosphere, Irwin's heart rate increased.

Medical effects
On their way home, Scott and Irwin suffered double heartbeats due to premature closing of the heart valves. In addition, Irwin suffered from mild dizziness. The astronauts were more tired from the flight than they thought. For this reason they needed a longer recovery period than in any previous flight. Getting used to the earth's gravity was somewhat slower.

Moon satellite
On the 425th lap, the satellite crashed on the far side of the moon. It is the height difference between the Praslanion - 5 km - and the peaks of the mountains that probably caused the satellite to crash.