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ТЕКСТЫ ДЛЯ АННОТИРОВАНИЯ

1. Four Electrons

On January 30, 1964, the Soviet Union used one carrier rocket to launch a system of two research stations: Electron-1 and Electron-2.

This system was designed for carrying’ out comprehensive, synchronized measurements at different points of near space. Such measurements were necessary for. a fuller and more detailed

belts and carrying out measurements of a number of other physical parameters according to a unified programme.

The simultaneous launching of two satellites in substantially different orbits was made possible by employing powerful carrier

Electron-4 carried instrumentation identical to that of Electron-1 and Electron-2, and were designed for the solution of similar problems.

2. First Soft Landing on the Moon

The soft landing of the Luna-9 probe on the Moon’s surface at 21 hours 45 minutes 30 seconds, Moscow Time, on February 3, 1966 was a new breakthrough in the exploration of that celestial body by means of spacecraft. The vehicle touched down in the Ocean of Storms west of the Reiner and Maria craters and on February 4 on command from Earth began scanning the moonscape and transmitting the pictures back to Earth.

Making a soft landing on a celestial body like the Moon which has no atmosphere is one of the most difficult engineering problems in astronautics,

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Since there is no atmosphere on the Moon, the conventional methods of landing spacecraft on the Earth cannot be applied. The spaceship’s velocity before landing on the Moon can be decelerated only by a retro-rocket system, and^ this necessitates considerable stocks of fuel on board, amounting to half the vehicle's weight before deceleration.

To ensure a soft landing on the Moon the vehicle’s rocket thrust during the slowdown must be controlled so as to reduce

the astro-orientation system, the autonomous control instruments, and to conduct scientific experiments,

3. Salyut-4

The Soyuz-18 was launched to conduct further experiments on the Salyut-4 orbital scientific station, launched on December 26, 1974, and to test the ship’s systems under different operational conditions.

The Soyuz-18 docked with the Salyut-4 on May 25. The approach was made with the help of an automatic system of control and then the cosmonauts completed the docking manually, from a distance of 100 metres. They then went over to the.station and started fulfilling their programme, which included continuing the scientific experiments and research begun by the first crew — cosmonauts A. Gubarev and G. Grechko, who spent 30 days in space.

The crew studied the Sun and other celestial bodies and the physical processes in the atmosphere. They also studied geological-morphological objects on the Earth’s surface and carried on with medical and biological research. The programme also included testing the station’s design, and its systemsa

4. Putting Moon Satellites into Orbit

On March-31, 1966, a powerful carrier rocket put a heavy Earth satellite into orbit with an apogee of 250 km and a perigee of 200 km. From this satellite a space rocket was launched and the latter put the Luna-10 probe into orbit as a satellite of’the Moon, with a maximum height of 1,017 km above the lunar surface and a minimum height of 350 km. ^This was the first artificial Moon satellite.

After that two more probes were put into orbit round the Moon: the Luna* 11 on August 28. 1966. whose minimum distance from

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the Moon is about 160 km, and maximum distance about 1,200 km, and the Luna* 12 on October 25, 1966, minimum distance 100 km and maximum distance 1,740 km.

The lunar satellites are intended for investigating the Moon and lunar space, specifically, the Moon’s gravitational field, gamma and X-ray radiation of the lunar surface, meteoric conditions, intensity of long-wave radio emission and radiation intensity. Launching the lunar satellites made it possible to test and develop techniques for the control of space vehicles while beingVput into lunar orbits. One of the missions of the Luna-12

solid-rocket engine in some applications, and inferior in others. The advantages of the liquid-propellant rocket lie in its higher

performance, its simple shutdown and restart capability, and the fact that it is easier to control. For example, the thrust of a liquid-propellant rocket can be varied at will, by throttling the propellant flow, and the rocket can easily be steered in flight by swiveling the relatively small engine or engines.

The advantages of the solid-propellant rocket lie in its simplicity. It need not be fueled just prior to launching. It needs no pressure system or pumps to feed the propellants from the tanks into the combustion chamber, since the rocket’s case combines the functions of both. The resulting simplification and^

.speedup of launch preparations make the solid-propellant rocketespecially attractive for military applications where quick response may be vital.

Pressure feeding is simple, but relatively heavy. Pump feeding offers a substantial weight advantage, at the price of greater complexity. In a pressure-fed rocket propulsion system, the fuel

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tanks. The main advantage of pressure feeding is simplicity. The weight disadvantage becomes less noticeable in some rockets, such as air-defense missiles. Due to their high accelerations, and aerodynamic loads caused by maneuvering within the atmosphere,

combination with highly efficient high-pressure rocket engines.

perfection of larger power plants of the more conventional types which are necessary for the initial phases of manned space investigation.

The most attractive approach to actual space travel with known propulsion entails the establishment of manned space satellite stations; these would provide take-off points for vehicles powered by the more efficient space propulsion systems already discussed. Advanced systems, such as the electrical and electro-magnetic, are quite efficient in their utilization of fuel; however, they yield a very low thrust that would be totally inadequate for overcoming gravity and the atmospheric drag of earth.

8. Factors Influencing the Determination of a Rocket’s Speed

In outer space — where the tug of gravity is extremely weak—' a rocket’s velocity depends on how fast gases are ejected from its exhaust nozzle and the amount of gases passing through the nozzle.

This is why scientists are searching for new fuels which will produce greater exhaust speeds and yet not take up too much room aboard a rocket ship. For really efficient space vehicles, however, scientists realize that nuclear powerplants or electrical

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engines will some day have to replace conventional chemicalpowered rockets. This is because nuclear rockets will convert liquid fuel (such as liquid hydrogen or helium) into gas very rapidly and expel it from the rocket’s nozzle at tremendous speeds. Another advantage of nuclear rockets is that less fuel is required — an important factor in interplanetary travel. Electrical rockets will expel their propellants many times faster than even the most efficient nuclear rockets.

The shape of a rocket ship will have no bearing on its speed. In outer space there is no air and consequently no resistance to slow down a speeding body, such as occurs in our atmosphere.

rockets and a few antitank rockets. Depending on the particular mission and the distance desired, the properties and fuel requirements of these missiles vary considerably. For short distances unguided rockets are often used effectively and with these low cost is probably the most important factor. At the other extreme is the intercontinental missile where extremely high performance of the fuel is required as well as a refined guidance mechanism. Cost is a minor factor for such an application. The medium or long range missiles are usually quite large in size and frequently multistage. This is because of the large quantity of fuel required to give the desired range. The step rocket is the best way to increase the mass ratio (ratio of fuel weight to dead weight) and reduce the overall size of a rocket for a given application. The large rockets also have relatively long burn

a planet will vary greatly from one planet to another. Although all the planets of the solar system move around the sun in the

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They'need the higher velocity to prevent the more powerful attraction of the sun from pulling them to it.

The return trip from the planet will be similar to the arrival. When the passengers take off, they will spend a number of days in a spiral away from the planet until they make contact

through space and return to the earth satellite from which the

launched directly into their deep-sp'ace trajectory. In the more recent past, however, they were first placed into a so-called parking orbit around the earth. After one or several revolutions the uppermost stage of the launch rocket was then restarted to drive the spacecraft on to its destination.

What advantage is offered by a parking orbit? From the point of view of celestial mechanics, a rocket could be launched from any point on earth directly to the moon or any planet. Placing a rocket temporarily in a parking orbit (around the

.earth) first is solely for convenience in carrying out the operation. It greatly widens the “launch window’’, the time span during which the launch may be performed. A parking orbit divides the earth-to-moon voyage into two distinctly separate phases of powered flight: the launch-to-orbit portion and the orbit-to-lunar-injection part. The rocket’s “stay time” in the parking orbit, until the right moment comes to start it on the second phase of its flight to the moon, may be a few minutes or several hours. Thus a parking orbit provides desirable slack between the “flexible” or possibly unpredictable timing of the ground launching and the “frozen” timing for translunar injection.

12. Requirements for Successful Re-Entry of an Orbiting Spacecraft

entire retardation energy with retrorockets is unattractive; it

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retrorockets are employed only for the limited task of pushing -the spacecraft’s orbital path back into the atmosphere. The bulk of the braking action is provided by ensuring aerodynamic drag. The drag is produced by air compression and air friction. Both generate heat. Suppose the kinetic energy of an iron ball entering the atmosphere at an orbital speed of 25,600 feet per second was completely converted into heat and all that heat was transferred back into the ball. It would never reach the ground,

a small fraction of the total heat generated during aerodynamic deceleration be absorbed by the spacecraft. The m<3st effective mechanism to carry energy away from the spacecraft and into the surrounding air is a shock wave.

13. The Use of Billiards Technique

To send a space probe directly towards the sun it is first necessary to cancel out the earth’s orbital speed of 62,750 miles an hour; At this speed travelling away from the earth back along the solar orbit, a space probe would be simply standing still in space relative to the sun and would begin to fall towards it. This is over twice the speed necessary to get as far as the moon and

solved by employing the billiards technique. By aiming the spacecraft at Jupiter, an enormous planet in an orbit some 364 million miles further away from the sun than we are, it would be possible to use its very large gravitational field to slow the spacecraft down so that it began to fall towards the sun. In this way a Saturn V could carry a very considerable solar probe, though the journey would take much longer.

The technique of interplanetary billiards is already being used to plan the routes of unmanned space probes for grand tours of the solar system. Normally a journey to Pluto, which is in orbit some 2,671 million miles away from earth at its nearest approach, would take forty-one years, but by using the gravity-bouncing technique this could be reduced to eight years.

14. The Soyuz-15 Mission

On 26 August 1974, the Soviet Union launched Soyuz-15 carrying a two-man crew —Gennady Sarafanov, commander, and Lev Demin, flight-engineer. The flight programme was intended to continue scientific research and experiments in space started on 3 July 1974 during the flight of the transport ship Soyuz 14 and the Salyut orbital station. The launch of Soyiiz 15, callsign “Danube”, came only 38 days after thetouchdown of Soyuz 14:

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The Soviet Union had never before launched a manned spacecraft

revolutions around the Earth. During the morning, a. trajectory

During their second day in space, the Crew carried out experiments to perfect the techniques of piloting the spaceship in different flight regimes. During these manoeuvres, Soyuz-15 approached Salyut-3 many times and inspected it. The cosmonaut’s second working day ended at 06.00 BST on 28 August, after Soyuz-15 had completed 22 revolutions of the Earth.

The cosmonauts made a successful re-entry, touching down near the town of Tselinograd, Kazakhstan at 21.10 BST on 28 August. The descent module touched down in rain and in darkness — the fifst time a Soviet crew had landed at night.

15. Electric Propulsion

Electric propulsion has been under serious study for the past decade, the principle motivation being potential capability and cost advantages resulting from its characteristically efficient use of propellant mass. The fuel economy derives from the use of electrical energy to drive propellant mass to exhaust velocities as much as an order of magnitude greater than that achievable in current competitive system. Higher exhaust velocity means that a lower propellant expenditure rate is required for a given thrust level and to achieve a given mission total impulse. As a result, payload of a given launch vehicle is increased, or launch-vehicle requirement for a given mission is reduced. Moreover, electric power available during nonpropulsion periods and at destination may be profitably used. Because electric propulsion systems will operate at low thrust levels and over an appreciable fraction of the mission time, they will have trajectory-related performance characteristics that differ in many respects from those of the familiar ballistic spacecraft. Such differences may provide advantages; for example, in the case of a Mars orbiter, both approach velocity and retropropulsion requirements are lower for the solar-electric spacecraft than the ballistic.

Electric propulsion systems have been tested in space and used operationally in an auxiliary propulsion role for satellite maneuvering. Power-source and thruster technologies have progressed to points such that a more expansive role can be

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ДОПОЛНИТЕЛЬНЫЕ ТЕКСТЫ ДЛЯ ЧТЕНИЯ

ИПЕРЕВОДА

1.The Programme of the Zond Probes

Zond-1 was launched on April 2, 1964, with the object of making further headway in organising a space system for longrange interplanetary flights. Radio commands transmitted from the Earth, switched on the apparatus aboard Zond-1 and the elements of the power supply systems. The commands set the operational conditions' of the stellar orientation systems which were adjusted by the control system of the space station.

The investigations conducted with the help of Zond-1 have revealed that the stellar orientation and correction systems have fulfilled the set progranime of work in outerspace conditions.

It has now been established that it is possible to solve problems pertaining to precise correction of trajectories followed by automatic space apparatus in flight.

Zond-2 was launched on November 30, 1964. This was the first time mat electro-jet plasma engines were tested in the conditions of space flight. Such motors were used on Zond-2 as control elements in the orientation system. The thrust of a plasma engine is easily regulated over a wide range by varying the electric power supply. It also has a big work potential. These factors make the use of plasma engines very .promising for space devices sent on lengthy flights.

Zond-3 was launched on July 18, 1965. The object of the flight was to carry out scientific investigations in distant interplanetary space, work out and test onboard apparatus and photograph the far side of the Moon.

Zond-3 was fitted out with instrumentation for studying the magnetic properties of near space and the interplanetary medium, the solar wind, low-frequency galactic radio emission, and micrometeorite particles, as well as for investigating the infrared and ultraviolet spectra of the lunar surface. Along with these studies tests have been made of plasma engines and also of certain materials in1the conditions of outer space,

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