Pioneer 10 and 11 spacecraft were sent to explore the planet Jupiter in the early 20s
introduction
Pioneer 10 and Pioneer 11 were the first two spacecraft designed to explore the planet Jupiter. The flight duration of each spacecraft was 600 days. They were sent for these purposes:
- Explore the planet Jupiter, measure its radiation belts and magnetic field, photograph its surface to determine its composition, measure the clouds surrounding it and uncover the mystery of its red spot.
- measure Jupiter's moons.
- On the way to Jupiter the spacecraft must pass through the asteroid belt and measure this region.
The structure of the spaceship Pioneer 10
The spacecraft is a regular Pioneer spacecraft stabilized by spinning at a rate of 60 revolutions around itself once a minute. The weight of the spaceship is 250 kg, 28 kg of the weight is weighed by various measuring devices. The spacecraft is mostly made of aluminum and is 2.9 meters tall. The spacecraft is equipped with a nuclear generator similar to those left by the Apollo pilots on the moon. The element that powers the generator is plutonium, and 40 watts can be produced from it at the beginning of the journey and 30 watts five years later. The lifespan of the spacecraft is 10 years. Each device consumes up to 4.2 watts of electricity. The spacecraft's transmitter has a power of eight watts.
The spaceship has a fuel load of 27 kg and is designed to perform course corrections during the flight through changes in speed and flight direction. Changes in the self-rotation speed (RPM) and changing the direction of the rotation axis are intended to maintain eye contact between the spacecraft and the Earth. The spacecraft has six small navigation engines on its sides. The propulsion system allows changes in speed up to 720 km/h.
An antenna with a diameter of 2.7 meters is installed at the bottom of the spacecraft, which is always aimed at the Earth. The axis of rotation of the spacecraft coincides with the center line of the radio beam transmitted from the spacecraft. Keeping in touch with the spaceship is done using three large DSN (Space Network Deep) antennas with a diameter of 64 meters each located in Goldstone in the United States, Madrid in Spain and Canberra in Australia. The orbit of the spacecraft is very close to the plane of the ecliptic where the Earth moves. The navigation of the spacecraft is performed by Doppler tracking and angular tracking and can be monitored directly from Earth.
The instrument box is flat and shaped like an elaborate hexagon, the length of each side is 71 cm. Attached to one of the six faces is a small box that is also hexagonal in shape, although not elaborate. The height of both boxes is 33.5 cm. Three arms protrude from the spaceship at an angle of 120 degrees from each other. The ends of the arms are attached to the nuclear energy sources. At a distance of three meters from the center of the spaceship. The third arm holds the magnetometer 6.6 meters from the center of the spacecraft.
spacecraft instruments
- • Photopolarimeter camera weighing 4.5 kg. The camera consists of a telescope with an opening of 2.5 cm for the overview of Jupiter. The light entering the telescope is separated into two to get a red image of the red wave region of the spectrum and blue of the blue light waves. The images appear in the form of a grid of lines with a resolution of 200 km.
- • Instruments for analyzing the solar wind, measuring magnetic fields in interstellar space, measuring the compositions of hydrogen and helium nuclei, counting tiny electrically charged particles and cosmic rays, measuring the strength of the particles in Jupiter's magnetic field using a magnetometer.
- • An ultraviolet photometer to measure the ultraviolet radiation of Jupiter's atmosphere.
- • An infrared radiometer for measuring the infrared radiation in the atmosphere and recording the temperatures prevailing on the planet's surface.
- • Instruments for measuring meteoric material.
- • A device for recording holes punched in the body of the spacecraft by particles weighing more than a billionth of a gram. In this detector there are 234 gas-filled cells that the particles hit and puncture.
- • A device for identifying larger particles by measuring the amount of sunlight they reflect.
the launcher
The launch was made by the 27-AC launcher consisting of three stages. The Atlas launcher, the Centaur launcher and the 4-364 ET-M launcher. The combination of these three launchers gave the spacecraft a speed of 51,800 km/h.
The identification board
Attached to Pioneer 10's antenna was a board that served as a sign to intelligent beings, if they existed, that would encounter the spacecraft. The panel shows a naked man and woman with the man's hand raised as a sign of friendship, the man and the woman are "non-racial". The woman's eyes are oriental, the man's features are negroid and both together can also appear white. All the drawn lines are the next code to clarify where the spacecraft came from. The radial lines express the 14 pulsars in the Milky Way galaxy. The 15th line on the right side symbolizes the place in the galaxy where the solar system is located and the place from which the spaceship leaves.
The course of Pioneer 10's flight
The spacecraft's flight can be divided into three phases:
1. The flight from Earth to the asteroid belt.
2. The flight in the asteroid belt.
3. The flight from the asteroid belt to Jupiter.
First phase, from March 3, 1972 to July 15, 1972
After several delays due to malfunctions and weather conditions, Pioneer 10 was launched on March 3, 1972. The original launch date was February 28, 1972. Malfunctions and unfavorable weather conditions and a conflict with the US Air Force, which launched a spy satellite on March 84, led to the postponement of the launch. On the day of the launch itself, strong winds were blowing at an altitude of XNUMX km and there was a fear that they would damage the spacecraft. These concerns were misplaced.
On March 6 - an engine test was performed and the communication system was directed towards Earth.
On March 7 - a correction was made to the flight path and the spacecraft's engine was turned on for eight minutes to accelerate the speed.
On March 8 - the engine was turned on for five minutes to make another correction on the flight path.
March 14 - there was a malfunction in one antenna.
March 23 and 24 - the spacecraft's engine was turned on again to postpone the transit time by Jupiter at half past two. The researchers hoped to reduce the transit distance near Jupiter by 6,400 km. This maneuver increased the chance of passing by Jupiter's moon Io.
March 25 - the spacecraft crossed the orbit of Mars.
July 15 - the spacecraft entered the asteroid belt.
By July 17, 56 small meteors had hit the spacecraft, 50% more than expected. The damages were extremely minor.
Second phase, from July 15, 1972 to February 15, 1973
On March 15, 1972, Pioneer 10 entered the asteroid belt and stayed there for 7 months. The biggest danger expected for the spacecraft is the impact of small asteroids. When the spacecraft entered this area, the spacecraft's cameras were activated to photograph these bodies.
On September 19, 1972, the speed of the spacecraft was accelerated by 14.25 km per second to advance its passage by Jupiter by 17.2 minutes. which allows passage even near the moon Io. The transition is carried out so that the spacecraft is between this moon and the earth and its distance from it is 329,000 km. This mode allows the passage of signals from the spacecraft through the entire atmosphere of Io, if indeed there is one. The accepted assumption was that the moon's atmosphere has methane and ammonia.
Until mid-October, Pioneer 10 encountered particles with a diameter of 0.01 - 0.1 mm. The number of these particles remained constant since the launch of the spacecraft and did not increase even after it entered the asteroid belt. Particles with a size of 0.1 - 1 mm were found throughout the journey of the spacecraft, their number tripled inside this strip compared to those outside it. Their frequency is greater than expected. Particles whose size exceeds one mm, their explosiveness is very small according to predictions.
Preliminary findings of Pioneer 10 indicated that the explosiveness of the dust particles in the area between the Earth's orbit and the outer orbit of the asteroid belt depends on the size of the particles. It can be assumed that there are many particles (0.001 mm) near the Earth, more in the asteroid belt itself. It was found that the asteroid belt has fewer particles of matter than first thought. This is especially true in relation to the tiny particles.
Up to a distance of 560 million km from the sun, the strength of the sun's magnetic field and the density of the solar wind gradually weaken and the number of high-energy solar particles decreases in more or less direct proportion to the square of the distance.
By December 3, 1972, Pioneer 10 was hit by ninety particles, but no significant damage was caused to her. While the spacecraft was in the asteroid belt it was hit on average once a day, even in the densest areas. Hydrogen, sodium and aluminum were identified among the particles emitted from the sun.
Third phase, from February 15, 1973 to December 4, 1973
During this period, the flight went well and without any problems. The only dangers that beset the spacecraft were the expected ones, and it is true that on November 9, the spacecraft entered the first danger zone in this part of the flight. A band of extremely heavy dust grains and radiation that surrounds Jupiter and contains protons and neutrons moving at the speed of light On November 26, five orbit corrections were made and on December 3 the last orbit corrections were made. From mid-November, the spacecraft transmitted to Earth photographs of Jupiter which became clearer and clearer as the spacecraft got closer to it. Three days later the spacecraft began transmitting information. On November 29, the speed of the spacecraft accelerated beyond the planned and it passed by Jupiter on the designated date - December 4, 1973, two minutes before the planned. It turned out that Jupiter is more massive than they thought and therefore its gravity is greater. Pioneer 10 passed at a distance of 140,000 km from it at a speed of 130,00 km/h. After completing its mission, Pioneer 10 continued in flight until it left the solar system. The astronomers hoped that the spacecraft would transmit information for another five years. In total, the spacecraft transmitted 340 photographs of Jupiter and some of its moons.
Pioneer findings 10
The magnetometer showed that due to Jupiter's high axial speed, 35,000 km/h, its poles at the equator are 10 times wider than those of the Earth. The diameter of Jupiter from pole to pole is 132,762 km and is smaller than the diameter at the equator by 9,280 km. The surface of Jupiter is probably not solid at all. Jupiter contains mostly liquid hydrogen and hydrogen in a solid state of aggregation enveloping the small rocky core. This assumption is based on the magnetometer measurements which showed that Jupiter has no special mass concentrations. Jupiter is in hydrostatic equilibrium and is almost liquid. From the gravimetric measurements it was possible to deduce the temperatures and pressures prevailing on the surface of the star. It turned out that Jupiter was too hot to start solidifying. The ratio between hydrogen and helium is 1:4 and reaches a depth of 960 km and the temperatures range from 155 degrees below zero to 2,000 degrees where the hydrogen turns into a liquid. At a depth of 3,050 km the temperature is 5,500 degrees and the pressure is 90,000 atmospheres. The density of hydrogen here is in the liquid state of aggregation and is 1/4 the density of water. At a depth of 24,000 km the temperature is 11,000 degrees and the pressure is three million atmospheres. The hydrogen is in a liquid state of aggregation and has metal-like properties.
Jupiter emits 2.5 times more radiation than it receives from the Sun. To allow such a high emission of energy in its core, which is 14,000 km in diameter, a temperature of 30,000 degrees must prevail, six times the surface temperature of the sun. From terrestrial observations, before the launch of Pioneer 10, it was clear that the emission of heat is higher than the absorption of heat from the sun. This emission is attributed to the slow contraction of Jupiter under the influence of its gravity or to radioactive materials disintegrating in the depth of the planet. The theoretical calculations raised the hypothesis that Jupiter is more of a Saturn star than a planet and indeed the findings of Pioneer 10 served as support for this theory. It turned out that on the light side and on the dark side the temperatures are the same, 133 degrees below zero. Apparently Jupiter's massive atmosphere is rotating at such a high speed that it is constantly merging the heat of the light side and the dark side. Justice can also be thought of as a giant greenhouse. Since it stores its heat and the heat of the sun in the cloud cover for a period of at least nine days. The heat is probably created in the center of the star. The difference between Jupiter and Earth is probably due to Jupiter's age. It is probably younger than the Earth.
Two assumptions have been made regarding the existence of these high internal temperatures. It is possible that the heat created during the formation of Jupiter was not dispersed in space or that much of the heat is released by hydrogen and helium particles near the center of the star. The first theory is explained by the fact that Io and Europa, the two closest moons to it, are rocky and arid in contrast to the outer moons which are icy. Hot Jupiter may have emitted a large amount of heat that prevented the vapor from turning into liquid and freezing when Io and Europa formed.
The high heat levels revealed two other important features. The hydrogen inside Jupiter moves in a circular motion, the convection currents move at a speed of 24,000 km per year and transfer the heat from the core to the surface. This movement creates an electric current and by dynamo effects, balanced magnetic field lines are obtained. The infrared radiometer showed that the equator is hotter than the poles, and just as there is no difference in the temperatures of the day and the temperatures of the night, so there are no differences in heat between the northern hemisphere and the southern hemisphere. No evidence has been found for the claim that Jupiter has rings like those of Saturn.
atmosphere
Earth observations have shown that Jupiter's atmosphere contains hydrogen, methane and ammonia. Pioneer 10 showed that Jupiter also has helium in its atmosphere and some deuterium (H2), acetylene (2H2C) and ethane (6H2C). Excluding hydrogen and helium, the rest of the elements and compounds make up 1% of the atmosphere. To the extent that the ratio of hydrogen and helium in Jupiter's atmosphere is reminiscent of this ratio in the Sun, and indeed the hydrogen-carbon and hydrogen-nitrogen ratios in Jupiter are reminiscent of those in the Sun, then the hypothesis is confirmed that Jupiter is similar in composition to the primordial composition of the solar nebula, and thus Jupiter and its moons will be able to clarify the processes of the formation of the solar system.
Jupiter is surrounded by colorful clouds. At the poles the color is dull gray and towards the equator the colors change rapidly in wide and narrow stripes of light blue, yellow, pink and white. The gray - white strips are warm. High clouds and gases took the form of bands due to Jupiter's high axial velocity. The dark orange-brown strips corresponding to the light strips are probably openings through which the cold gases descend.
The clouds reach up to a height of 240 km from the surface of the liquid and at the same distance from the limits of the outer atmosphere. The clouds are divided into four layers. The top layer is a layer of ammonia ice crystals and the next layers, in order, are a red-brown ammonia layer with sulfide crystals, a layer of water ice crystals and a layer with water droplets containing ammonia in solution. The infrared radiometer revealed that the temperature at the top of the clouds is 120 degrees below zero and the atmospheric pressure is 700 millibars, near the poles the cloud bands are hot. It is estimated that the transparent outer atmosphere contains traces of methane and ammonia. 12.8 km above the cloud layer the temperature drops to 145 degrees below zero and above these cloud layers there is probably a fog layer of ammonia crystals that expands upwards to the opposite layer at a temperature of 155 degrees below zero and the pressure is 100 millibars.
Jupiter has an ionosphere that is 10,000 km above the clouds. This phenomenon is quite strange considering that Jupiter emits radio waves. A normal ionosphere receives the radio waves transmitted from the star and returns them to the ground. The ionosphere was discovered 2,900 km above the level where a pressure of 0.1 millibar prevails. It is 10 times deeper than thought and five times hotter than expected. The prevailing temperature in the ionosphere is 1,000 degrees.
Meteorology
The visible signs on Jupiter are actually meteorological phenomena. A red spot and a small red spot that appear in the Pioneer 10 photographs appear to be evidence of strong storms that have been moving for centuries. The red spot is probably the vortex center of a tornado storm that is 40,000 km long and moves above the star's cloud belt. In the photographs you can see subtle formations of the stain.
The bright bands and the dark bands surrounding Jupiter as rings respectively raise and lower gases that are stretched around it by the Coriolis force created by Jupiter's high axial velocity and the deep interior of the atmosphere. Pioneer 10's instruments detected spots rising 8 km above the cloud layer. This phenomenon was discovered due to the fact that the atmosphere above the clouds at the top of the spots is thinner. These clouds are colder and therefore higher than the clouds surrounding Jupiter. The disappearance of the spots from the magnetometer suggested that they had physical characteristics.
The spacecraft's findings suggested that the spots are relatively short-lived and appear in the luminous layers of the atmosphere. The bands and belts of the atmosphere are analogous to the terrestrial cyclone and anti-cyclone systems on Earth. The warm air rises and falls vertically and with the help of the Coriolis force the air moves around the earth. in the west-east direction. Unsteady flow moves these fluctuating amounts of air into spirals of cyclones and anticyclones across Jupiter's surface. Several factors combined to have a quiet effect on the atmosphere, so that the movement is essentially linear. These factors include a uniform burst of heat on the star's core, the absence of a solid ground, and the liquid nature of the star itself. Atmospheric gases heated by Jupiter's internal heat and solar radiation spread toward Jupiter's stable bands. The peaks of the bright bands are 9 degrees colder than the dark bands and are 19 km higher than them. In general, the belts are warm, gently raising weather cells with the help of clouds of ammonia crystals, while the bands are colder and lower cells colored by clouds containing red-brown crystals of ammonium sulfides.
magnetic fields
Jupiter's electromagnetic environment is the most extensive and complicated in the solar system. This environment is surrounded by two concentric magnetic fields. The internal magnetic field is inclined at an angle of 10 degrees towards the axis of rotation and is shifted 2,100 km north and 8,700 km parallel to the equator from the center of the star. The strength of the magnetic field at the tops of the clouds is 10 times greater than that existing on the surface of the earth and it spreads up to a distance of 1,280,000 km in space. The external magnetic field starts at a distance of at least 3,350,000 km from the top of the clouds and reaches a distance of 10,400,000 km in space. The polarity of the field is reversed so that the compass needle moves south.
It is possible that the outer ring is flat with a thickness of 710,000 km and its distance from the inner ring ranges from 2.2 to 9.6 million km. The maximum strength of the outer field is hundreds of times weaker than that of the inner ring. The magnetic fields rotate with Jupiter around itself and their direction is outward. The particles are ionized in the plane close to the equator, the movement of the ionized particles creates an electric current in the plane and due to all this the magnetic field is flat.
The internal magnetic field includes high-energy particles captured from the solar wind, such as those found in Earth's Van Allen belts. The strength of the magnetic field is 1,000 times greater than that of the Earth. The frequency of electrons is a million times higher than in the terrestrial radiation belts. The spacecraft's instruments were shielded to prevent damage, although the meteoroid probe and ultraviolet photometer were badly damaged. Jupiter's enormous magnetic field follows the assumption of astronomers about the elongating "ring of Saturn" and the "hula hoop" model which says that the magnetic field lines spread out near the equator and curve near the poles.
A day before the deadline, the spacecraft's instruments detected the solar shock wave enveloping Jupiter. This wave consists of charged particles erupting from the Sun in a horseshoe-like curve around the star, a discovery that increased the danger of spacecraft damage to a greater extent than expected at the most critical stage, passing through the radiation belts. A week later, the spacecraft entered the field of radiation which, as mentioned, caused damage to the meteoroid instrument, the ultraviolet photometer and the loss of photographs of Jupiter and two of its moons Io and Abaddo.
meteorites
During the transit near Jupiter, the spacecraft was suddenly hit by an average of 10 small meteorites per hour. The impact of the meteorites during the flight was 1 to 25 days. This phenomenon shows that the magnetic field of Jupiter, absorbs and concentrates the particles that are scattered in its path during its orbit around the Sun. The amount of dust here is 300 times higher than in the entire flight area.
moons
The density of the Galilean moons decreases as you move away from Jupiter. The average daytime temperature in each of them is 145 degrees below zero.
Ao
Io is about the size of Mercury. Its massiveness is 1.22 that of Earth's moon. Its density is 3.5 grams per cubic centimeter like that of the Earth's moon, more than they thought. It is a body with rock-like structures and is made of iron rocks. Io is an arid and rocky body. The Pioneer 10 measurements confirmed the assumption that Io has its own atmosphere. This is an atmosphere that rises to a height of 110 km and is devoid of charged particles. The ionosphere is thin and resembles in its density the ionosphere of Venus. The source of the assumption about the existence of an atmosphere is the orange color of the moon. It turned out that the source of the color is sodium and sulfur found on the surface of the moon.
10 minutes after Io's exit Jupiter's shadow is the best reflecting object in the solar system before it slowly returns to its natural, orange color. When it is behind Jupiter, flakes of frozen methane fall and cover the ground, only to thaw and evaporate as Io emerges into sunlight. Io is permanently surrounded by a cloud whose length is 1/3 of the length of its orbit around Jupiter and with the characteristic sodium glow it can be seen from a distance of 320,000 km.
EUROPE
Its massiveness is 0.67 that of Earth's moon. A body with rock-like structures. It is arid and rocky and has an area of high radiation.
Ganymede
Its size is about the size of Mercury and its massiveness is 2.02 times that of the Earth's moon. His photograph shows two smooth sea surfaces, one at the South Pole and the other near the equator, a bright area at the North Pole and several large impact craters. Ganymede is hotter than Io. The reason for this probably lies in the presence of an atmosphere on its surface. It is an icy planet and appears to contain more elements than water ice.
Callisto
Its massiveness is 1.44 times that of Earth's moon. It is an icy planet containing more elements than water ice. Callisto is outside Jupiter's radiation intensity range and seems more suitable for manned landings.
Pioneer 10 findings after Zedek's departure
From the spacecraft's transmissions made in February 1974, it became clear that since it left Jupiter it had been hit by two meteorites, while dust particles were being discovered in the area. The impacts suggested that the concentration of material beyond Jupiter's orbit is the same as that between the outer boundary of the asteroid belt and Jupiter. The device for measuring the solar wind ordered for 24 hours at a power of 0. At first the compromise of this information was not understood. Later it turned out that Jupiter has a magnetic "tail" 690 million km long that crosses the orbit of Saturn. As soon as the spacecraft entered the "tail", this field completely enveloped the spacecraft and rejected the solar wind. The meaning of the discovery is that Saturn enters the tail once every 20 years. The next time such an event occurred was in April 1981 and in the early XNUMXs.
