Researchers at the Jet Propulsion Laboratory were deprived of their quiet rest for a long time. Excited by the discoveries, they slept in fits and starts, and when they woke up, they hurried back to the Mission Control Center of the automatic interplanetary station Voyager. Here, digital machines operated with fabulous speed, transforming thousands of bits of information, distorted by space and atmospheric interference, into telechronicle frames, slender graphics and endless rows of numbers. People with bated breath looked at the color images of the approaching Saturn on the screens.
33 million kilometers remained to the space reconnaissance planet. 4 years have passed since its launch at the cosmodrome, and a long road stretches behind Voyager for 2 billion kilometers. The dangerous Asteroid Belt with its endless streams of meteorite bodies has been safely crossed. Fragile electronic devices withstood the severe cold of world space and electromagnetic storms in the vicinity of the largest planet in the solar system - Jupiter.
And ahead? The risk of collisions with rocks and ice floes near Saturn before Voyager embarks on its 8-year voyage to the most distant planets - Uranus and Neptune.
… A grandiose picture appeared before the eyes of those who were in the Control Center. Saturn, crowned with a huge "necklace", already occupied almost the entire frame of the television image. A golden-yellow planet with grayish poles and motley belts barely discernible in the fog rushed and spun in the black abyss of the sky.
Researchers fix their gaze on the famous rings of Saturn, which have haunted astronomers for several centuries.
The great Galileo was the first to notice something strange in the appearance of Saturn. Galileo's telescope was too weak, and it seemed to the scientist that Saturn had handles like a sugar bowl. Only half a century later, Christian Huygens proved that the strange semicircles on the sides of the planet are nothing more than thin, but very wide rings.
The distance to the planet is 33 million kilometers. On the screen, there are three rings of Saturn, long discovered with the help of telescopes: A, B and C. However, in the space imagery, you can see something that cannot be seen from Earth. First of all, the complexity of the structure of the rings and their amazing color.
The largest ring - the outer one - sparkles with a silvery color, the middle one is slightly reddish, and the inner one is dark blue, it is translucent, as if made of thin, barely tangible matter.
8 million kilometers. Only a fourth of Saturn's hemisphere fits on a television image. On the side of the planet, two moons closely pressed against each other shone - Tethys and Dione. But scientists are persistently returning to the study of rings. Not three, but seven rings, nested one inside the other, are visible. Here they are, newly discovered: F - outside the old A, G - outside the new F, E - the widest ring farthest from the planet, D - the closest to Saturn.
But what is it? Comparing photographs, experts see that each of the large rings breaks up into many narrow, barely noticeable "hoops". In one photo they were counted 95! Even in the black "gap" 4 thousand kilometers wide between rings A and B, which has always been recognized as empty, scientists have counted dozens of thin "hoops".
2 million kilometers. Voyager's instruments are aimed at rapidly approaching Titan, Saturn's largest moon. It is larger than the planet Mercury. Astronomers' excitement is easy to understand. Titan is the only satellite in the entire solar system with a powerful atmosphere 10 times thicker than Earth's. Voyager flew past Titan at a distance of 6, 5 thousand kilometers - 60 times closer than the distance from the Earth to the Moon. And yet, scientists saw little on the screen - the thick fog of Titan's atmosphere, similar to chemical smog, prevented.
1 million kilometers. On the screen, the dazzlingly bright Rhea is the second largest moon of Saturn. It is all pitted with craters - the continuous space bombardment lasted for billions of years. Another satellite gleaming in the velvety blackness of space came into view of the camera. This is Dione, which is more similar to our Moon than other objects of the Saturn system, but the "seas" on Dione are not covered with solidified lava. Water ice is visible everywhere, solid as stone. The network of white "ropes" speaks of the places where the water bursting out from the bowels instantly solidified, enveloped in a fierce frost. Dione's surface temperature is minus 180 ° С - here the sun shines 900 times dimmer than in Earth's orbit.
The previously unknown satellite Saturn-12 (S-12) floats before the eyes of the researchers. Surprisingly, it is in the same orbit as Dione. In this case, S-12 always flies ahead of Dione at a distance of 1/6 of the orbital circumference. In celestial mechanics, such a phenomenon is usually called orbital resonance.
300 thousand kilometers. Date with Saturn is coming soon. From the left side of the scout, as if welcoming his arrival, Mimas appeared. He looks strange. Billions of years ago, this satellite collided with a large celestial body - a colossal explosion tore so much ice and stone from Mimas's body that a crater 9 deep and 130 kilometers wide was formed. The crater occupies a quarter of the satellite's hemisphere!
101 thousand kilometers. At such a distance, the giant planet and the messenger of the Earth met and parted. Saturn is so great that during the hours of closest approach, only a small patch of cloud cover could be seen in the television frame. Clouds of yellow-brown color, impenetrable to the eye, are everywhere. Among the fluctuating white stripes, vortices and halos run some blue-green spots, the size of Greenland or Australia - these are "windows" through which gas vortices from the depths of the planet break through.
Of all the planets in the solar system, Saturn is second only to Jupiter in size. Inside it, there would be enough room for three hundred globes. But the average density of the giant is very low - if a fantastic endless ocean existed somewhere, Saturn would float on its surface like a cork.
According to the new model, created by Voyager's instruments, the planet appears to us as an oblate ball of hydrogen and helium at the poles. The powerful gaseous envelope of Saturn, with increasing pressure, turns into a liquid state closer to the center. Liquid planet to the very core!
And what about the solid core? It is the size of the Earth, but has a mass 15-20 times more. So high is the density of matter in the center of the planet, where the pressure is 50 million Earth atmospheres! And the temperature is + 20,000 degrees! The liquid ball boils, and in the upper tier of the planet's clouds, a severe cold reigns. How does this huge temperature difference arise? With the vastness of the planet's interior and its colossal gravity, gas flows take hundreds of years to transfer the heat of the depths to the upper cloud layer of Saturn's atmosphere.
Strange rain
Saturn radiates into space three times more energy than it receives from the Sun. First, heat is created by the gradual contraction of the gas giant - its diameter decreases by millimeters per year. Besides, Saturn has another fantastic source of energy. The red-hot sphere of Saturn has been cooling since the very birth of the solar system. According to the calculations of astrophysicists, 2 billion years ago, at a great depth of the planet, the pressure of the interior fell below the critical point of helium concentration. And it began to rain … Strange rain that pours to this day. Drops of helium fall for many thousands of kilometers in the thickness of liquid hydrogen, while friction arises and thermal energy appears.
Stormy weather
Under the influence of the planet's rapid rotation (any point on the equator of Saturn moves 14 times faster than on the equator of the Earth), winds of monstrous force blow in the mysterious world - in one place Voyager's equipment recorded the speed of the clouds of 1600 km / h. How do you like this refreshing breeze?
Voyager's camera lenses slide into Saturn's southern hemisphere. Suddenly, an oval spot tens of thousands of kilometers long appeared on the screens of the Mission Control Center - a copy of the Great Red Spot on Jupiter. The planet Earth can freely fit inside the spot. But this is just a raging atmospheric vortex in the atmosphere of Saturn, which has no end.
Crash
Voyager was continuing its flight past Saturn when radio communications were suddenly cut off. Scientists were not worried - according to calculations, the device disappeared into the "radio shadow" of the planet. When the scout "emerged" from the other side of Saturn, the situation became really serious. The steering mechanism of the turntable with instruments is jammed. Wouldn't it be possible to photograph the night side of the planet ?! It is a pity that due to a technical malfunction, the planned meeting with the large satellites - Enceladus and Tethys - will have to be canceled.
Signals poured from the Control Center to the onboard computer of the interplanetary station. The control over the repair of the mechanism was complicated by the cosmic distance - the delay time of the radio signal between the Earth and Saturn is 1.5 hours. In the end, Voyager's digital brain unlocked the targeting drives of the TV cameras, but time was lost and only Tethys became closely acquainted.
When the device was already moving away from Saturn at a speed of 22 km / s, scientists saw an electric storm in the rings of Saturn. Lightning, illuminating the shadow side, cast red highlights on the planet's night clouds …
The finale of the space play
The events described above took place in 1980-1981, when two automatic interplanetary stations Voyager 1 and Voyager 2 flew past Saturn. To avoid repetitions, I decided not to talk about them separately - all the news about the Saturn system, transmitted to Earth by two devices, conditionally "put into the mouth" of one under the name "Voyager" (no number).
It becomes a little offensive to realize that after three decades, our space technologies have remained at the same level.
Every night, when the sun sets and the darkening sky is covered with a scattering of stars, we see the Cosmos. Space exploration requires fantastically sophisticated technology based on the advanced achievements of rocketry, electronics, nuclear technology, and other science-intensive branches of science and technology. Therefore, flights of interplanetary probes, despite their seeming unrealism and lack of any practical benefit, require the solution of numerous applied problems: the creation of powerful and compact energy sources, the development of technologies for long-range space communications, the improvement of structures and engines, the development of new methods of gravity assist maneuvers, including.h. using Lagrange points. This entire front of research can become the "locomotive" of modern science, and the results obtained can be useful in solving more pressing problems. Nevertheless, most of the problems remain unresolved.
All modern timid attempts to explore the outer planets (Ulysses, Cassini, New Horizons missions) are all based on the same technologies and developments that were used in the Voyager project. For 30 years, not a single new type of engine has been created, suitable for interplanetary flights. For example, the ion thrusters of the Japanese research probe Hayabusa, which are touted as ultra-modern high-tech, are in fact well-forgotten developments of the mid-twentieth century - ion thrusters were widely used in the attitude control systems of the Soviet meteorological satellites Meteor. Secondly, ion engines are a rather specific tool: they really have amazingly low fuel consumption (a few milligrams per second), but, accordingly, they create thrust of several millinewtons. It takes many years to accelerate a spacecraft, and as a result, no real benefit is obtained.
Conventional liquid-propellant jet engines (LPRE), not only are very voracious - their work is limited to tens (hundreds) of seconds, in addition, they are not able to accelerate the spacecraft to the required speed, for example, to reach the orbit of Saturn. The fundamental problem is that the gas flow rate is too low. And it is not possible to raise it in any way.
The peak of fashion in the 50s - the nuclear jet engine did not receive development, due to the lack of any significant advantages. Despite the unquenchable flame of a nuclear reactor, such an engine requires a working fluid - i.e. in fact, this is a conventional liquid-propellant rocket engine with all the ensuing consequences and disadvantages.
The original way to travel in space using the pulses of nuclear explosions, proposed by Freeman Dyson in 1957 (Project Orion), remained on paper - too daring, and, frankly, a dubious idea.
The "conquerors of space" (here it is ironic in relation to all of Humanity) for 50 years of the Space Age have not been able to create an effective engine for moving in interplanetary space. We would never have seen either Jupiter or Saturn, if not for a hint from specialists in celestial mechanics - to use the gravity of the planets to accelerate the AMS. "Interplanetary billiards" allows you to gain tremendous speed (15-20 km / s) without using an engine and explore the outskirts of the solar system. The only problem is the strictly limited "launch windows" - a few days (weeks) once every few years. No room for the slightest mistake. Long years of flight and a few hours for a rendezvous with the object of research.
With the help of gravitational maneuvers, the Voyagers flew, the modern New Horizons probe flies to Pluto according to the same scheme, but it will take 9 years only to cross the solar system. And then the expedition will have only one day to explore a distant planet! The probe will rush past Pluto at great speed and disappear forever into interstellar space.
