EntrancePioneer 10 spacecraft. The strange braking of the “pioneers” is revealed
NASA specialists were able to determine the cause of the mysterious braking of the Pioneer 10 and Pioneer 11 space probes, which was even attributed to the action of unknown laws of physics. It turned out that this process is associated with the technical features of the devices themselves, the equipment of which generates electrical and thermal effects that create jet thrust.
Pioneer 10 became the first spacecraft to reach escape velocity and photograph the planet Jupiter. It was launched on March 2, 1972. An anodized plate made of a durable aluminum alloy was installed on the body of the device, which depicted a message to potential extraterrestrial civilizations: a molecule of neutral hydrogen, two human figures against the background of the outline of the aircraft, a diagram of the solar system, etc.
In 1973, the probe crossed the asteroid belt and flew at a distance of 132 thousand kilometers from the clouds of Jupiter, thanks to which data was obtained on the composition of the planet’s atmosphere, its mass, magnetic field parameters and other characteristics, including the density of Jupiter’s four largest satellites.
The space station crossed the orbit of Saturn in 1976, Uranus in 1979, and Pluto in April 1983. On June 13, 1983, the device first flew through the orbit of the planet Neptune, the farthest from the Sun. The Pioneer 10 mission officially ended on March 31, 1997, but the device continued to transmit data. In February 2012, the ship began to move away from the Sun at a speed of about 12.046 kilometers per second, quite sufficient to enter interstellar space.
In turn, Pioneer 11 was launched on April 6, 1973. It was distinguished from its “twin” only by the presence of an induction magnetometer for measuring intense magnetic fields near planets. In December 1974, he flew at a distance of 40 thousand kilometers from the edge of Jupiter's clouds and transmitted detailed images of the planet to Earth. In September 1979, the probe passed at a distance of about 20 thousand kilometers from the cloudy surface of Saturn, made various measurements and transmitted photographs of the planet and its satellite Titan to Earth. After completing its research mission, the probe left the solar system and should now be on its way to the Scutum constellation. In 1995, contact with the device was lost. It is known that in February 2012 it was moving away from the Sun at a speed of 11.391 kilometers per second.
The anomaly was discovered back in 1998, when both probes moved 13 billion kilometers from the Sun. Then NASA researchers noticed that their speed began to slow down with an acceleration of 0.9 nanometers per second squared. After crossing the orbit of Pluto, the probes began to deviate from the given trajectory. Experts concluded that this could not be caused by the influence of solar gravity.
The known laws of physics did not answer the question of the reasons for what was happening; it was even suggested that this phenomenon contradicts Einstein’s general theory of relativity. Perhaps the satellites are affected by “dark matter”! We are talking about the curvature of space, which actually means a transition to another dimension! This is how science fiction fans rejoiced, having received a lot of food for thought.
However, experts also remembered that something similar had already been observed in the early 1980s, when some unknown force began to “pull” the devices back towards the Sun. True, then an explanation was found: they say, it’s all about the remaining fuel that evaporated from the tanks during the flight past Saturn. However, now there is not a drop of fuel in the tanks of the Pioneers, and yet their speed continues to slow down.
In 2004, scientists began collecting archival information regarding the Pioneers and other similar equipment. Not only computer data was used, but also paper media and tape recordings. As it turned out, the “anomaly” was observed only among the Pioneers. For example, the Voyager probe did not show any braking...
Eventually, the cause of the strangeness was revealed. It turned out that the electric current of scientific instruments and heat generators on board the devices creates a very weak jet thrust, which is almost impossible to notice under normal conditions.
47 years, 4 months, 26 days
Project website]
Design
- energy source -
- electronics compartment.
- communication with the Earth - through a parabolic antenna with a diameter of 2.75 meters
The device carried the following scientific instruments:
- plasma analyzer,
- charged particle detector,
- set of Geiger counters,
- cosmic ray detector,
- radiation detector, ultraviolet photometer,
- imaging photopolarimeter,
- infrared radiometer,
- a set for observing meteoric matter and a set of meteor particle detectors.
The mass of the apparatus was 260 kg, including 30 kg of scientific instruments; height - 2.9 m, maximum transverse size (diameter of the highly directional antenna reflector) - 2.75 m. The images transmitted by the device had low resolution, since they were taken not by a camera, but by a photopolarimeter, which had a very narrow field of view (0. 03 degrees). Scanning along one coordinate occurred due to the rotation of the spacecraft, and along the other - due to its movement in orbit. 
"Interstellar Letter" of Pioneer 10
An anodized plate made of durable aluminum alloy was installed on the body of the device. The dimensions of the plate are 220x152 millimeters. The author of the drawing is Carl Sagan.
The plate shows:
- neutral hydrogen molecule;
- two human figures, men and women, against the background of the outline of the apparatus;
- the relative position of the Sun relative to the center of the Galaxy and the fourteen pulsars;
- schematic representation of the Solar system and the trajectory of the vehicle relative to the planets.
A drawing of a hydrogen molecule is shown as consisting of two atoms with different spins. The distance between the centers is proportional to the wavelength of neutral hydrogen radiation (21 centimeters). This number is a scale ruler for finding other linear quantities on the plate. The height of the people on the plate can be found by multiplying the number 8 (engraved in binary code next to the figure of the woman in square brackets) by 21. The dimensions of the apparatus in the background are given on the same scale.
Fifteen lines diverging from a single point make it possible to calculate the star from which the device arrived and the launch time. Next to the fourteen lines is a binary code that indicates the period of pulsars located in the vicinity of the Solar System. Since the period of pulsars increases over time according to a known law, it is possible to calculate the launch time of the device.
On the diagram of the Solar System, next to the planets, the relative distances from the planet to the Sun are indicated in binary form.
Criticism of the message
Many of the symbols in the picture may be incomprehensible to another mind. In particular, such symbols can be square brackets framing binary numbers, an arrow sign on the Pioneer’s flight path, and a man’s raised hand in greeting.
The further fate of the device
In 1976, the device crossed the orbit of Saturn, and in 1979, the orbit of Uranus. On April 25, 1983, the station passed the orbit of Pluto, which at that time was closer than Neptune to the Sun. On June 13, 1983, the device was the first to cross the orbit of the most distant planet in the solar system - Neptune. The mission of Pioneer 10 officially ended on March 31, 1997, when it reached a distance of 67 AU. from the Sun, although the device continued to transmit data. February 17, 1998, at a distance of 69.419 AU. Pioneer 10 ceased to be the most distant man-made object from Earth, as it was overtaken by the Voyager 1 spacecraft. In 2002, the latest telemetry data were received, since then it has not been possible to detect useful signals from Pioneer-10. By 2009, the device had moved away to 100 AU. from the sun .
Having flown quite far beyond the orbit of Neptune, the device began to experience a force of unknown origin, causing very weak braking. This phenomenon was called the “Pioneer” effect. Many assumptions have been made, including as yet unknown effects of inertia or even time. Some spoke simply of systematic measurement error. The reason for the constant acceleration turned out to be the asymmetry of the thermal radiation of Pioneer 10 itself.
The last, very weak signal from Pioneer 10 was received on January 23, 2003, when it was 12 billion kilometers (80 AU) from Earth. It was reported that the device was heading towards Aldebaran. If nothing happens to it along the way, it will reach the vicinity of this star in 2 million years.
see also
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Links
- - Online book about Pioneer 10 and Pioneer 11 with photographs and diagrams.
- - article in CNN, December 19, 2002
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American program for the exploration of interplanetary space and selected celestial bodies. Under this program, several automatic interplanetary stations were launched. Since 1958, the launch of spacecraft under the Pioneer program began. The most famous interplanetary stations were Pioneer 10 and Pioneer 11. These were the first spacecraft that managed to reach and leave the two outer planets of the solar system (Jupiter and Saturn). All spacecraft in this series were completely different both in design and in their missions.
The launch mission of the first three spacecraft of the Pioneer series was to study the Moon and take photographs of its far side, invisible from Earth. However, this was a scientific goal. There was also another goal - a political one, in terms of which was the return of the United States to the status of the most developed technical country in the world, since this status wavered after the Soviet Union launched the first Earth satellite.
The first attempt to launch the station failed - Pioneer-0 exploded during takeoff on August 17, 1958. On October 11, 1958, the Pioneer 1 station was launched, but it did not reach the speed, flew only one-third of the distance from the Earth to the Moon, and burned up in the atmosphere. Pioneer 2 launched on November 8, 1958, and it also suffered from failure - the device had a malfunction in the third stage, as a result of which it had to return to Earth.
The next two devices were supposed to study the Moon from a flyby trajectory. Pioneer 3 launched on December 6, 1958, but also did not reach speed, did not reach the Moon, and burned up in the upper atmosphere the day after launch. However, during the flight the device managed to detect the Earth’s second radiation belt. On March 3, 1959, the Pioneer-4 apparatus was launched, which was similar to the Pioneer-3 station. “Pioneer-4” was engaged in studying the radiation situation near the Moon from a flyby trajectory, but it was not possible to take photographs of the surface of the satellite. Pioneer 4 became the first American spacecraft to reach escape velocity.
After all the launches and research, NASA formulated the following tasks within the program: launching vehicles into lunar orbit, obtaining television images of the Moon and measuring its magnetic field. For this purpose, the stations were improved by building a new generation of probes, but, unfortunately, all the next four launches (“Pioneer P-1”, “Pioneer P-3”, “Pioneer-30”, “Pioneer P-31”) were unsuccessful.
The following devices of the Pioneer series turned out to be surprisingly durable. One of the devices in this series, launched on December 16, 1965, Pioneer-6, is still in operation. All devices, from the version “Pioneer-5” to “Pioneer-9”, were engaged in research of the solar wind, studied cosmic rays and the Earth’s magnetic field.
The Pioneer 10 and Pioneer 11 spacecraft, launched in March 1972 and April 1973, respectively, are the most famous vehicles of this series. These were the first spacecraft that managed to reach the third escape velocity and also explore deep space. In December 1973, the Pioneer 10 spacecraft flew past Jupiter. His mission was to explore the planet's surroundings and obtain photographs of it. In 1974, Jupiter passed Pioneer 11, and in 1979 it reached Saturn. In 1978, the last two probes in the Pioneer series were sent into space to explore Venus - Pioneer Venera 1 and Pioneer Venera 2.
Upon reaching escape velocity 1, the object will enter a closed orbit around the celestial body and remain there. Upon reaching escape velocity 2, the object will be able to overcome the gravitational attraction of this body and go to other planets. When reaching the 3rd escape velocity, the object will be able to leave the solar system forever and go to the stars...
To date, there are few such objects - only five vehicles have reached the 3rd cosmic speed and it is difficult to say when this list can be replenished. If some kind of global catastrophe happens on Earth, then it is possible that these devices will remain the only proof of the existence of human civilization.
Pioneer-10 and Pioneer-11
So. the first spacecraft to reach sufficient speed to leave the solar system forever was Pioneer-10. Launched in March 1973, it followed a flyby path near Jupiter and then headed towards the constellation Taurus. Contact with Pioneer 10 was lost in 2003, and it is now located at a distance of 108 AU. from the Sun and continues to move away from us at a speed of 2.536 AU. in year. It is assumed that in 2 million years, Pioneer 10 may pass near one of the stars included in the Hyades open cluster (where Aldebaran is located, by the way).
The second device was Pioneer-11, which was launched in April 1973. After studying Jupiter, the device was sent to Saturn, which was not initially part of NASA's plans - adjustments were made during the flight. After passing near Saturn in 1979, no further course corrections were made and the device set off on an eternal journey towards the constellation Aquila. Communication with the device was lost in 1995. It is now located at a distance of 88 AU. from the Sun and continues to increase it annually by 2.396 AU, which makes it the slowest of all the “five”. It is assumed that in about 4 million years, Pioneer 11 may approach one of the stars of the constellation.
At the insistence Carla Sagan, shortly before launch, an aluminum plate with symbolic information about the Earth, its location was placed on board the Pioneers (to obtain metric and time units on the plate, the radiation pattern of the hydrogen atom was reproduced, as well as a map of pulsars, on which the position of the Sun in the Galaxy is marked), and a schematic drawing of a person against the background of the apparatus, so that hypothetical aliens could better imagine the scale.
A plate attached to the Pioneer
Interestingly, the authors of the message were subsequently subjected to a barrage of criticism. They were accused of racism (after all, the picture shows white people), pornography (after all, the people in the picture are naked - by the way, the image of the woman was censored, depriving the line indicating the vulva), that aliens would not be able to read it, that they would not be able to understand the meaning of the greeting gesture of the man in the picture, and in the end, that you should not send such information into space, because it can be dangerous.
Actually, the same drawing engraved on the plate
It is worth noting that 9 planets of the solar system are drawn on the plate (after all, Pluto was still considered a planet at that time), and in the case of Pioneer 11, its trajectory is indicated incorrectly. After all, as already mentioned, the maneuver to Saturn was not planned, and in reality the device left the Solar System along a trajectory that was actually opposite to that indicated.
And yet, if something happened to the Earth, perhaps these records will be all that will remind us of our existence. By the way, James Van Allen in his autobiography, he jokingly admitted that shortly before the launch he deliberately left his fingerprints on the body of Pioneer 10 in the hope that they would circle around the center of our galaxy for millions of years and perhaps even outlive the Sun.
Voyager 1 and Voyager 2
The third and fourth vehicles to reach escape velocity were the famous Voyagers. Launched in 1977, they first studied Jupiter and Saturn. The last goal Voyager 1 there was Titan - having flown close to the satellite, the device received a significant increase in speed due to the gravitational field, which ultimately made it the fastest of all five devices. Voyager 1 is currently located at a distance of 124 AU. from the Sun and continues to move away from it annually by 3.593 AU, while moving in the same direction as the Sun. In 40,722, the device will pass at a distance of 1.7 light years from the red dwarf AC+79 3888.
Concerning Voyager 2, then it lost part of the speed increase received from Saturn during the flyby of Uranus, but then partially compensated for these losses due to the gravitational maneuver at Neptune. It is now located at a distance of 102 AU. from the Earth and continues to move away by another 3.253 AU each year. Due to its greater speed, over time it will overtake Pioneer 10 and become the second spacecraft farthest from the Sun, but it will not be able to overtake Voyager 1. In 40,000 years, Voyager 2 will pass at a distance of 1.7 light years from the star Ross 248, and in another 256,000 years it will come within 4.3 light years of Sirius.
The Voyager mission was much more ambitious than the Pioneer mission. It is not surprising that this time scientists prepared a message in advance for possible aliens.
On board each of the Voyagers, an aluminum case was placed inside which contained a 30-centimeter gold-plated copper plate. Along with the record, a phonograph capsule and a stylus for playing the recording are packed in the case, and on the case itself there is an engraved diagram showing the installation of the stylus on the recording surface, the playback speed and the method of converting video signals into an image. In addition, as in the case of the Pioneers, the galactic coordinates of the Sun were indicated on the surface of the case. The record itself contains music, sounds of the Earth, greetings in 50 languages, and 116 images are encoded. Since the defenders of morality were not asleep this time either, there were no photographs of naked people in these photographs either.
On the left is the case itself, on the right is the record with “Sounds of the Earth” contained in it. There is an assumption that over the course of millions of years, cosmic dust will damage it so much that it will be impossible to read information from it. But it’s better than doing nothing at all. 
And here are NASA instructions on how to decipher the image on the case
New Horizons
And finally, the last device to reach the 3rd cosmic speed by this time was the probe New Horizons, launched in 2006 to study Pluto. Since its mission is still ongoing and course corrections are possible, the exact trajectory along which the device will leave the Solar System and its final speed are still unknown. It is only clear that the speed of New Horizons will be higher than that of the Pioneers, and less than that of the Voyagers - which means that in the list of the most distant man-made objects from the Earth it will take an honorable third place.
For some reason, this time NASA decided not to leave any messages addressed to extraterrestrial civilizations. But several souvenirs did get on board the device - two American flags, two coins, two CDs containing the names of 434,738 people who participated in the “Send Your Name to Pluto” campaign, a postage stamp, a piece of the first private spaceship SpaceShipOne and capsule with a particle of ashes of the discoverer of Pluto Clyde Tombaugh. If in the future some intelligent individuals intercept the device, they will probably puzzle over the purpose of these objects for a long time.
Schematic representation of the trajectories of all five vehicles leaving the solar system
I would like to note one more interesting fact - so far the capabilities of earthly technology do not allow reaching the 3rd cosmic speed when launching from Earth. Each of these five devices gained the missing speed due to the gravitational maneuver at Jupiter, which can give a speed increase of up to 40 km/s.
Other objects leaving the solar system
Concluding this mini-review, it is necessary to mention that in addition to this “five”, there is another group of objects that are destined to leave the Solar System forever. We are talking about the last stages of the launch vehicles that launched all these devices into space. Since they moved along approximately the same trajectories as the ships themselves, it is assumed that after passing near Jupiter these stages accelerated enough to be enough to reach the 3rd cosmic speed. The only exception is the last stage of the rocket that sent Pioneer 11 into space, which, according to calculations, should have simply entered a heliocentric orbit.
One can inevitably ask the question - if there are other intelligent species in our galaxy that are destined to find artifacts left by humanity, then which of all this will be found with a greater degree of probability? And on the other hand, if we ourselves find artifacts of extraterrestrial origin, then what will they be - some complex and advanced technology containing indications of who created it, or simply space debris? And don’t potential aliens have analogues of our guardians of morality, deciding for other intelligent species what can be considered obscene and what should not be sent into space?
The mass of the apparatus was 260 kg, including 30 kg of scientific instruments; height - 2.9 m, maximum transverse size (diameter of the reflector of the multi-directional antenna) - 2.75 m.
Four SNAP-19 plutonium-238 radioisotope generators (RIGs), manufactured by Teledyne Isotopes from fuel disks at the Los Alamos Laboratory, were chosen as the power source, with a total power of 155 W at the beginning of the flight and 140 W by the time it arrived at Jupiter. To power the spacecraft systems, 100 W were needed, and for scientific equipment - another 26 W. The excess power was charged to a silver-cadmium battery or emitted through a radiator. In order for the RIGs to create as little interference as possible with scientific equipment, they were installed at the ends of two rods, retracted 3 m away from the body after separating the spacecraft from the carrier. A magnetometer sensor was placed on the third rod, 6.6 m long.
The orientation and stabilization system included a Canopus star sensor and two solar sensors as measuring tools. Of the six nozzles, two looked down along the spacecraft axis, two upward, and two - tangent to the circumference of the LGA antenna. There was no computer on board. In principle, on-board computers already existed at the time of the creation of the Pioneer 10 spacecraft, but they were still too large and heavy. The absence of a computer automatically meant the need to issue a large number of commands from Earth, mostly in real time. If, of course, we consider radio exchange with Jupiter as such: 45 minutes “there”, 45 “back”.
A parabolic antenna with a diameter of 2.74 meters and a depth of 46 cm was installed on the spacecraft.
The sealed chamber of the apparatus was a hexagon 36 cm deep, each side of which was 71 cm in length. Attached to each side was a module designed for a specific scientific experiment.
Also installed:
High gain antenna;
- antenna with medium gain;
- omnidirectional antenna;
The spacecraft radio system included, in addition to the three mentioned antennas, two 8 W transmitters using traveling wave tubes with a frequency of 2292 MHz (S band) and two receivers at a frequency of 2110 MHz. Any transmitter could be connected to an HGA antenna or an MGA/LGA pair. The on-board digital telemetry unit could prepare data in 13 different formats (with the ability to identify and correct bad bits) for reset at speeds from 16 to 2048 bps. The highest speed was intended for the initial stage of flight when receiving on a 26-meter antenna; reception from Jupiter was already carried out on a 64-meter antenna at a speed of 1024 bps. For temporary storage of information on board, a storage device with a capacity of 49152 bits was used.
Over the command radio line at a speed of 1 bit/s, it was possible to transmit 222 different commands - from 149 to control spacecraft systems and 73 to control scientific equipment. Two decoders and a command distribution unit determined the validity of each command and its recipient. Since the command consisted of 22 bits, it took 22 seconds to receive it on board. Therefore, the device also had a program memory for five commands that could be executed one after another at specified time intervals. To ensure the specified duration of operation of the spacecraft - 21 months, the developers simplified the board as much as possible at the expense of complicating the ground part. The main components were duplicated, the rest were put on board only if they had experience of use in space.
February 15, 1973, at a distance of 3.7 AU. from the Sun, Pioneer 10 emerged from the asteroid belt intact and approached Jupiter.
In the gravitational field of the gas giant, the station gained speed sufficient to leave the Solar System. As a result, Pioneer 10 crossed the orbit of Saturn in February 1976, the orbit of Uranus on July 11, 1979, and the orbit of Neptune on June 13, 1983 at 30.28 AU. from the Sun, still having a speed of 13.66 km/s. Over the next 20 years, the craft went another 50 AU, continuing to measure cosmic rays and solar wind in what is now known as the Kuiper Belt.
Various experiments were carried out until the equipment failed and as long as the device’s power was sufficient. In 1989, a plan was developed to save energy on Pioneer 10, according to which instruments for scientific experiments worked according to a certain program - they were either turned off or restarted.
The asteroid and meteorite detector ceased operation in 1973, followed by the helium vector magnetometer in November 1975 and the infrared radiometer in January 1974. The meteorite detector was turned off in October 1980 due to the failure of the low temperature sensor. The solar sensors became unusable in May 1986. The photopolarimeter was turned off in October 1993 to conserve energy. The radioactive particle receiver and plasma analyzer were turned off in November 1993 and September 1995 for the same reason.
In January 1996, the remaining power was divided between the charged particle detector (CPI), the corpuscular telescope (CRT), the Geiger Tube Telescope (GTT) (at launch the power of the generators was 155 W, and now it has decreased to 65 W) and the ultraviolet photometer.
In August 2000, only GTT was still transmitting data. True, the telescope was subsequently turned off in order to save energy for turning on the attitude control system engines during the upcoming trajectory correction.
It was previously announced that the adjustment was successful, but it recently became clear that the probe did not carry out the command sent.
Having flown far enough beyond the orbit of Pluto, it began to experience a force of unknown origin, causing a very weak braking. This phenomenon was called the “Pioneer effect.” Many assumptions have been made, including as yet unknown effects of inertia or even time. Some people simply talk about systematic measurement error.
Jupiter exploration
In 1973 and 1974, Pioneer 10 and Pioneer 11 passed by Jupiter at a distance (from the clouds) of 132 thousand km and 43 thousand km, respectively. In 1973, Pioneer 10 crossed the asteroid belt for the first time, examining two asteroids and discovering a dust belt closer to Jupiter. In December 1973, the device flew at a distance of 132 thousand km from the clouds of Jupiter. Data were obtained on the composition of Jupiter's atmosphere, the mass of the planet was clarified, its magnetic field was measured, and it was also established that the total heat flow from Jupiter is 2.5 times higher than the energy received by the planet from the Sun.
In addition to the Great Red Spot, whose dimensions exceed the diameter of our planet, a white spot with a diameter of more than 10 thousand km was discovered. An infrared radiometer showed that the temperature of the outer cloud cover was 133 K (-140 C). It was also discovered that Jupiter emits 1.6 times more heat than it receives from the Sun.
The gravity of Jupiter greatly changed the flight path of the device. Pioneer 10 began to move tangentially to the orbit of Jupiter, moving away from the Earth almost in a straight line. Interestingly, a plume of Jupiter's magnetosphere was discovered outside the orbit of Saturn.
Pioneer 10 also made it possible to clarify the density of the 4 largest satellites of Jupiter.
The device transmitted several hundred images (low resolution) of the planet and Galilean satellites.
Pioneer 10 detected intense radiation emanating from Jupiter and a huge magnetic field, suggesting the presence of conductive fluid in the planet's interior.
Radio measurements indicated the height of the ionosphere of the Io satellite from 50 to 100 km above the surface. No one expected to see it at an altitude of 900 km above Io. The differences between the Pioneer and Galileo readings indicate that Io's atmosphere and ionosphere are changing in response to Io's volcanic activity. Io's gravitational field appears to allow invisible gas ejected from volcanoes to reach extreme heights, compared to the low altitudes reached by dust and other volcanic emissions that reflect sunlight and can be seen in photographs.
Pioneer 10 and Pioneer 11 photographed Ganymede at close range, revealing persistent dark and light green formations. An increase in the concentration of asteroid particles was noticed only once - during the week at around 2.7 AU. from the Sun, and on average their number turned out to be much less than expected: if in March-June 41 dust particles hit the spacecraft sensors, then in June-October 1972 - 42. Pioneer 10 proved that the asteroid belt does not pose a practical danger; but he discovered a dust belt much closer to Jupiter. On November 6, experimental surveys of Jupiter with a photopolarimeter began from a distance of 25 million km, and on November 8, the station crossed the orbit of Sinope, the planet’s most distant satellite. A 60-day period of flight began, during which about 16,000 commands were transmitted on board. On November 26, the device crossed a shock wave at the boundary of Jupiter’s magnetosphere (the speed of the solar wind decreased by half, the particle energy jumped 10 times), and on November 27 it passed the magnetopause. On November 29, it passed all the outer satellites and entered the inner region of the Jupiter system.
Regular surveying of Jupiter began on November 26. A special ground-based system converted individual scans of the IPP photopolarimeter, obtained while the device was rotating, into a series of images of the planet. They came in two color ranges - blue and red, from which a “green” frame was first artificially synthesized, and then a color photograph. The images taken during the day before the flyby and the day after it were more detailed than those available from earth-based telescopes. In total, more than 500 images were taken from the board. In order to protect the device during the flight from executing random commands caused by radiation near Jupiter, a “medicinal” package was sent on board every few minutes; in addition, a special command sequence immediately restored the operation of the photopolarimeter in the event of a failure. Such disruptions began at a distance of 9 radii of the planet and occurred 10 times; several close shots of Jupiter and the only planned shot of Io were lost. Without this glitch, Io's volcanoes could have been discovered 7 years earlier!
Pioneer 10 took the last photograph of Jupiter on approach from a distance of 203,000 km, and the first on departure - at a distance of 504,000 km. The station also imaged Europa and Ganymede, although at low resolution. During the radio occultation of Io, it was discovered that this moon has a weak atmosphere up to 115 km high and an ionosphere extending over 700 km, and there is a hydrogen cloud along Io's orbit. The device carried out the first direct measurements of Jupiter's magnetic field, the characteristics of charged particles, compiled a heat map of the planet, and determined the composition of the upper atmosphere. The planet turned out to be slightly heavier than astronomical calculations gave, approximately the mass of the Earth's Moon, and Pioneer 10 arrived at the target a minute earlier than the estimated time. On December 4, 1973 at 02:25 UTC the station passed at an altitude of 132252 km above the cloud boundary of Jupiter at a fantastic speed of 36.7 km/s. The flight altitude was chosen for the purpose of reconnaissance of the radiation situation.
15 experiments were conducted to study interplanetary and planetary magnetic fields, parameters of the solar wind, cosmic rays, the transition region of the heliosphere, the region of neutral [non-ionized] hydrogen, the distribution of masses, sizes, fluxes and velocities of dust particles, auroras and radio emissions of Jupiter, the planet's atmosphere and her companions, especially Io. Many photographs have been taken of Jupiter and its moons.