Cheap launching of cargo into reference orbit. Which of the options is most realistic? Orbits around the earth Putting spacecraft into orbit

To launch two spacecraft, a single-launch scheme is being considered using the SOYUZ LV and FREGAT LV. Figure 10 shows a diagram of the launch of the first spacecraft into the working orbit. The LV brings the warhead (SC and RB) onto a circular support satellite orbit 200 km high. On the first orbit of the reference orbit, the first RB is turned on (

V 1), resulting in head part transferred to the first transfer orbit, in which the apogee altitude is 350 km, and the perigee argument differs from the perigee argument of the working orbit of the first type by 180°.

In this orbit, in the apogee region, the second switching on of the RB takes place

(V 2) and the warhead is transferred to the second transfer orbit. The apogee height of this orbit is equal to the apogee height of the working orbit of the first type. After this, the first spacecraft launched into a working orbit of the first type is separated from the upper stage. Further maneuvers of this spacecraft are carried out using its own propulsion system. A detailed description of this stage is given in section 3.8.

The RB with the remaining second spacecraft continues to form an equatorial working orbit. Figure 11 schematically shows this stage of formation of the working orbit of an equatorial spacecraft. To do this, in the area of ​​the descending node of the second transfer orbit, the third switching on of the RB remote control is carried out and the head part is transferred to the fourth transfer orbit, which is located almost in the plane of the Earth's equator. After this, the second spacecraft, launched into a working near-equatorial orbit, is separated from the upper stage. Further maneuvers of this spacecraft are carried out using

own propulsion system. A detailed description of this stage is given in section 3

.8. This completes the tasks of the accelerating unit.

The energy costs of the Fregat RB and the spacecraft propulsion system during the formation of working orbits are summarized in Table 5.

Table 5

	Purpose	Value, m/s
	Formation of the first transfer orbit
	Formation of the second transfer orbit
	Formation of the third transfer orbit
	Total costs of RB “Fregat”
	Formation of the working orbit of the 1st spacecraft (PS of the 1st spacecraft)
	Formation of the working orbit of the 2nd spacecraft (PS of the 2nd spacecraft)
	Corrections for phasing of the 1st and 2nd spacecraft	20.0 for each spacecraft
	Corrections of working orbits of the 1st and 2nd spacecraft (approximately once a month for 3 years)	110.0 for each spacecraft

When launching a satellite into orbit, the launch vehicle usually imparts its initial speed after crossing the dense layers of the atmosphere at an altitude of at least 140 km. At the moment when the required orbital speed is reached, the engine of the last stage of the launch vehicle is turned off. Further, one or more artificial satellites designed for different purposes can be separated from this stage. At the moment of separation, the satellite gains a small additional speed. Therefore, the initial orbits of the satellite and the last stage of the launch vehicle are always somewhat different from each other.

In addition to one or more satellites with one or another equipment and the last stage of the launch vehicle, some parts are usually launched into close orbits, for example, parts of the nose cone that protects the satellite when passing through dense layers of the atmosphere, etc.

In Fig. Figure 34 shows a diagram of the launch of the Vostok satellite. On April 12, 1961, on the Vostok spacecraft, Yu. A. Gagarin made the first manned orbital flight in history.

In principle, the starting point of the satellite's motion can be any point in its orbit, but the characteristic speed of the launch vehicle will be minimal if the active segment ends near perigee. In the case when the perigee is located near dense layers of the atmosphere, it is especially important that the speed acquired by the satellite during acceleration is not less than given value and so that its direction deviates minimally from the horizontal. Otherwise, the satellite will enter the dense layers of the atmosphere without completing even one revolution (such objects are not registered as satellites).

If the planned orbit is located high enough, then small errors do not threaten the destruction of the satellite, but because of them

the resulting orbit, even if it does not cross the dense layers of the atmosphere, may be unsuitable for the intended scientific purposes.

Rice. 34. (see scan) Diagrams of the Vostok, Soyuz launch vehicles and the stages of launching the Vostok spacecraft into orbit - 1 - one of the four side blocks of the first stage, 2 - the central block (second stage), 3 - the third stage of the Vostok rocket, 4 - head fairing of the Vostok rocket, 5 - third stage of the Soyuz rocket, 6 - Soyuz spacecraft, 7 - head fairing of the rocket The orbital insertion phase usually includes one or more passive intervals. At a sufficiently high

perigee of the orbit into which the satellite is launched, the passive phase of the launch may be longer.

The launch trajectory, which is, generally speaking, a spatial curve, is located near the satellite orbital plane. If the launch is made exactly in the easterly direction, then the inclination of the orbital plane is equal to the latitude of the launch site. In this case, the orbital plane touches the parallel. In all other cases, the orbital inclination can only be greater than the latitude of the cosmodrome (in particular, when launching at westward, when the orbital plane also touches the parallel of the cosmodrome, the inclination should be greater than 90°).

The orbital inclination can be less than the latitude of the launch site only if a maneuver is provided to change the orbital plane after the launch.

In the active phase, a satellite may separate from the launch vehicle even before the last stage is turned off. After switching off, the second satellite may separate. Obviously, the orbits of the two satellites will be different, but their perigee altitudes will differ little, since during the additional acceleration the last stage could not rise too high. Apogees can be at completely different heights, because even a small increase in the initial speed sharply raises the apogee (remember Fig. 17 in § 5 of Chapter 2). Using this method, the Soviet Elektron-1, -2 satellites were launched in January 1964 to study the inner and outer parts of the radiation belt (perigees at altitudes of 406 and 460, and apogees at 7,100 and 68,200 km, respectively).

All of the above is also true if, instead of a launch vehicle, a reusable apparatus is used - an orbital aircraft piloted by a person (see § 4 of Chapter 7).

Let's return for a moment to project No. 7 “Superskyscraper”. Let's imagine that we are in our super skyscraper at a height h> 35.9·10 3 km above the Earth’s surface, that is, we are standing on the ceiling upside down. It is clear that on the same ceiling we can easily place the same massive ball that the baron is talking about. If we now tie this ball to the floor with a light and strong cable, then the cable will be taut(Fig. 8.1). That is, the ball will have a “desire” to fall on the ceiling on which we are standing.

If we now throw the end of the cable out the window so that its lower end reaches the ground and fasten the end of the cable near the ground, then the ball will pull the entire cable (if, of course, the mass of the cable is significantly less than the mass of the ball).

Now we will tie the satellite that we are going to launch into orbit to the lower end of the cable, and carefully move the ceiling on which the ball stands. Then the ball will begin to rise up on its own (!), carrying with it the satellite tied below. And, mind you, we don’t seem to be supplying any energy to our ball from the outside!

Let's wait until our satellite rises to altitude h= 35.9·10 3 km (it is at this height that the bodies are in weightlessness), let’s stop it, disconnect it from the cable and... with a slight push, gently push it out the window. And our satellite will immediately become a real satellite of the Earth, which moves in the so-called geostationary orbit: it rotates around the center of the Earth with a revolution period of 24 hours and at the same time, as it were, “hangs” over the same point on the earth’s surface all the time.

Note that from the point of view of physics, this satellite will be no different from a resident who will hang between the floor and ceiling in his apartment located at a height h= 35.9·10 3 km above the Earth's surface! So in theory The baron's plan is absolutely correct.

Now let's answer the questions of his opponents.

The engineer is wondering how tall our tower should be. It is clear that it is significantly higher than 35.9·10 3 km. And the higher, the better. After all, the greater the distance from the ball to the center of the Earth, the stronger the centrifugal effect!

The businessman is very optimistic that this tower will save a lot of money on launch space rockets. He is certainly right, but with one small caveat: the savings will begin After that how the tower will be built, and before that - just pure expenses. There is reason to believe that such construction is a rather expensive undertaking.

The most serious objection was expressed by the Professor: he believes that the proposed project is a project for another perpetual motion machine that produces work without consuming any energy. And the very fact of the existence of a perpetual motion machine contradicts the law of conservation of energy!

The professor is right: a perpetual motion machine is impossible in principle, but the proposed model is Not perpetual motion machine. In fact, the rise of the ball upward due to the centrifugal effect occurs due to the energy of the Earth's rotation. That is, the higher the ball rises on our tower, the slower the Earth will rotate around its axis! Let's prove it.

Unfortunately, in Lately The topic of various accidents during the launch of spacecraft does not lose relevance, therefore (based on my own experience) I would like to talk about what problems engineers solve when such an emergency situation occurs. The article describes possible scenarios for the development of events in the event of an abnormal launch of a spacecraft, using the example of the completion of the operation of the Express-AM4 telecommunications satellite after the failure of the Briz-M upper stage. I’ll also tell you a little about what is being done in the world to reduce the risk of collisions between spacecraft during abnormal launches.

Introduction

To begin with, it’s worth saying a few words about yourself. My main job is ballistic support for the descent of manned and unmanned spacecraft to Earth. This includes both direct operational work and the development of software for it.

Now some definitions:
By abnormal launch we mean the launch of a spacecraft into an undesigned orbit in which it can exist for some time. It is pointless to consider the option when “something went wrong” right away, since in this case nothing can be done.

Why do you even need to do anything with the device in the event of a launch accident?

First of all, being in an off-design orbit, a spacecraft may pose a collision threat to other operating vehicles. Well, secondly, in the event of a collision of a spacecraft with space debris(the number of which is increasing every day), there is a high probability of detonation of the fuel remaining on board and the formation of a large number of fragments.

One example of an abnormal launch into orbit was the Express-AM4 satellite. In August 2011, it was supposed to be launched into geostationary orbit (altitude 35,786 km) to provide telecommunications services to the population. However, due to an upper stage failure, it remained in orbit with a minimum altitude of 655 km and a maximum altitude of 20430 km. At this altitude, the satellite posed a threat to a large number of spacecraft, including GPS and GLONASS constellations (their altitude is 19,000 - 20,000 km).

Options for the development of events

Depending on the type of accident during launch, 3 main options for further developments are considered:

1. Continuation of the mission taking into account the emergency situation that has arisen.
2. Transfer of the device to a safe orbit (disposal orbit).
3. Flooding of a vehicle in a given area of ​​the World Ocean.

In the case of Express-AM4, the option of continuing the mission was impossible, since it was impossible to reach geostationary orbit using its own engines. In this regard, the last two options were examined in detail.
Let's start with a safe orbit (literally in a nutshell). The essence of the problem was to use the orbital catalog to determine the parameters of the orbit in which the satellite would pose the least danger to other spacecraft, and then calculate the flight pattern to this orbit with minimal fuel remaining on board. As a result, the burial orbit was chosen with the following characteristics: minimum altitude 12,000 km, maximum altitude 15,500 km. To fly to this orbit, 3 engine burns were needed: 1st to increase the perigee, 2nd to lower the apogee, and 3rd to completely exhaust the fuel and final transition to the given orbit.

In theory, the option with a burial orbit was not bad, but from a practical point of view it was quite difficult to implement (due to the peculiarities of the engine start-up interval, the peculiarities of the orientation of the device, etc.), and to guarantee precise entry into a given orbit with full exhaustion no one could have fuel. Therefore, the main option was to sink the satellite in a given area of ​​the World Ocean.

It's worth clarifying a little here: Before removing anything from orbit, it is necessary to coordinate the impact area with various organizations; this is necessary, first of all, to ensure the safety of the local population. Russia has an agreement on the use of the area Pacific Ocean in the Southern Hemisphere to flood Progress trucks. Thus, when the Express was sunk, options for targeting this area were first considered. But due to the peculiarities of the orbit (the perigee latitude argument was in the Northern Hemisphere), the use of this area was not possible. I had to look for an area in the Northern Hemisphere. There was no better place between the West Coast of the United States and Japan, so it was decided to sink the Express there.

Also, a reserve area was selected for insurance (it is smaller in the picture). To justify the possibility of satellite flooding in these areas, falling trajectories were calculated for different time periods. As can be seen from the figure, they all satisfied the condition of falling into a given area.

Operational work

Next came the most interesting part – direct implementation. I’ll say right away that all control of the satellite was carried out from the control center in Toulouse, and all work was carried out jointly with French colleagues. The approved flooding scheme is shown in the figure.

Let me explain a little: To bring a spacecraft out of a highly elliptical orbit, it is necessary to slow it down at apogee, while the perigee decreases and the craft enters the dense layers of the atmosphere. IN in this case The thrust of the satellite's engines did not allow the braking impulse to be processed quickly enough, so a scheme was chosen in which the satellite reached the apogee of the orbit in the middle of the propulsion system operation. This made it possible to work out the braking impulse with maximum efficiency.

To improve reliability, any dynamic operations on spaceships try to carry out in the radio visibility zone of ground points. Since the engine was turned on not over Russian territory, and the domestic orbital constellation of relay satellites is not so well developed, it was necessary to use partner ground stations in Uralla (Australia) and Beijing (China). According to their data, March 25, 2012. At the estimated times, the engine was turned on and off. After this, calculations were carried out that confirmed the flooding of the satellite in a given area.

Conclusion

At this stage of development space technology, not every device can do anything in case of an emergency during launch. This is primarily due to the high cost of each kilogram launched into orbit. For example, in order to increase the operating time of satellites in geostationary orbit, electric rocket propulsion systems, which have very low thrust, are installed on them. In the event of an accident with a satellite with such engines, neither the transition to a safe orbit nor its flooding becomes possible.

At a meeting with French satellite manufacturers, they expressed interest in further research into the possibilities of fending off abnormal situations during launch. Now work is being carried out in the direction of studying the possibility of additional installation of engines, development of the orientation system and many other components of the satellite. Perhaps, in the near future, satellites will be equipped with equipment capable of autonomously making decisions about their further actions in the event of an emergency launch.

Of course, it’s impossible to fit all the features of the return of spacecraft to Earth into one article, but for a start, I think it’s enough.

To launch a spacecraft into orbit, the launch vehicle (LV) must impart to it a very specific speed, both in magnitude and direction at the given coordinates of the launch point. This is ensured by the flight program, the implementation of which occurs when the control elements act on the launch vehicle.

The launch vehicle, starting vertically, then enters a curved section of the flight path, during which the angle of inclination of its axis to the local horizon gradually decreases. In dense layers of the atmosphere, the launch vehicle moves along a trajectory close to the trajectory with zero lift, i.e. the movement occurs with a zero angle of attack.

The speed required to launch a spacecraft into a circular orbit in the central gravitational field of the Earth (first escape velocity) is calculated by the formula

Where g– free fall acceleration for the Earth’s surface, g= 9.80665 m/s 2 ; R– average radius of the Earth equal to 6371 km; H– the height of the spacecraft’s orbit above the Earth’s surface.

For the Earth's surface, as is known, the first escape velocity is 7.9 km/s, for km (LEO - low Earth orbit) km/s, for GEO - 3.076 km/s.

For elliptical orbits, the final velocities are in the range between the first and second cosmic velocities (7.9 ... 11.2 km/s). It should be remembered that by using the rotation of the Earth around its own axis, when launching a launch vehicle with a spacecraft in the easterly direction, you can obtain an additional speed increment equal to 465 m/s for the equator. For the latitude of the Plesetsk cosmodrome (Russia, 63°00′N 41°00′E) – 210 m/s.

In practice they are implemented various methods launching a spacecraft into orbit, differing from each other in the required energy, thrust change program, parameters of the launch vehicle stages, launch duration, etc. However, the main requirement that determines the choice of the launch type is energy minimization. There are three main types of spacecraft launch into orbit:

– fully active output (direct output);

– ballistic output;

– elliptical output (with or without a section of motion along a perigee circular orbit of radius equal to the perigee distance of the transfer orbit).

At direct elimination There is only one active section, the motion parameters at the end of which must coincide with the required orbital parameters of the spacecraft. This type of output, compared to the two subsequent types of output, is less economical, since as the duration of the active section increases, the energy consumption to overcome gravitational forces increases. This method is advisable to use for launching spacecraft only into LEO (up to 400 km). Here great importance The question arises of choosing a launch vehicle movement program that ensures minimum energy consumption.

At ballistic conclusion trajectories are realized that are arcs of elliptical trajectories in the central gravitational field. In this case, the top of the elliptical trajectory must touch the orbit into which the spacecraft is launched. At the top of the spacecraft trajectory, an additional impulse is imparted to the required orbital speed (second active section). This launch method, compared to others, provides direct visibility during launch and more favorable conditions To save individual stages of the launch vehicle, less time is spent on decommissioning. The ballistic type of launch involves the least energy consumption at spacecraft orbital altitudes of up to 1000 km.

Elliptical output- the most economical way to transfer a spacecraft from one circular orbit to another (from the point of view of rocket fuel costs). With an elliptical launch, the spacecraft is first launched into LEO at an altitude of 180 ... 200 km, where (immediately or after a certain period of time) it is accelerated to the perigee speed of the transition ellipse, at the apogee of which, touching a given orbit, the spacecraft is accelerated to the required orbital speed. Those. the transition occurs along a semi-elliptical path that touches the inner (smaller) circular orbit from the outside, and touches the outer (larger) circular orbit from the inside. Such transitions are called semi-elliptical or Hohmann transitions after the German scientist W. Hohman, who first proposed using them for interplanetary travel.

The geostationary orbit is widely used in astronautics. It is considered the most profitable from an energy point of view to launch a spacecraft into geostationary orbit from launch pads at the equator. Launching a spacecraft to GEO from Russian cosmodromes is more complex, as it requires an additional change in the spacecraft orbital plane. This energy-intensive maneuver is carried out, as a rule, by special repeatedly switched-on stages of the launch vehicle - upper stages. In this case, injection methods are used, including passive sections and reference orbits. Currently, two- and three-pulse launch schemes, as well as the use of the gravitational field of the Moon to rotate the spacecraft orbital plane, have received practical application.