ENGLISH

:





1.
2.
3.
4. 40
5. ()
6. .
7. 100 ..








-





sinara.pro
RB2 Network

RB2 Network

.


     Nikolai Lavrentiev

   MARS - FAR AWAY AND YET SO CLOSE


    Astronautics, as it used to be known, is passing into oblivion. Man has reached Earth orbit, carried out missions to the Moon, built the international space station, and sent probes to most of the planets of the solar system. However, we have not seen the revolutionary changes required for the realization of extended spaceflight. The rocket engines used for space missions still burn chemical fuel. Their operation follows Newtons 3rd law of motion. The weight of a space vehicle consists of fuel, fuel tanks, engines, guidance system, communications systems and payload. The systems that orient and propel the space vehicle require huge amounts of fuel, but refueling stations in space non-existent. That is why such systems are suitable only for short trips into space, or for the startup of automatic space stations where the risk to life because of engine failure or empty fuel tanks is absent. A high percentage of space vehicle failures are due to these systems as well. Essentially, nothing has changed since the time of the first satellite launching to the propulsion systems in use for spaceflight today. We have improved the engines. They are a little bit more powerful, more reliable, and the control of these engines is much improved, but they are still fiery monsters who devour huge amounts of fuel.
    All of the proposed manned missions to Mars are based on the Newtonian method of propulsion: fuel or some other matter is ejected in one direction, and the complete spacecraft gets rotated or pushed in the opposite direction. Sometimes a nuclear engine, such as an ion-drive engine is suggested for the project. The underlying plan here is based on increasing of speed of the material that is thrown out in order to get the maximum thrust in the opposite direction.
    The reliability of the engines, which consist of pipelines, valves, injectors, pumps and other elements are significantly less than 100%. Reliability calculations consist of a long chain. All the elements of the engine are put into the chain as a percentage and then multiplied together to give an overall reliability. All the moving components of a design and high temperature chambers for combustion reduce the reliability even more. The failure rate increases again based on the duration of the mission. It turns out that the longer the mission, the lower the chance for its safe return. Sadly, the principles used in these systems to ensure proper orientation and propulsion of space vehicles has reached its limits. A new design for future long space missions is desperately needed. Conquest of deep space is impossible without the development of new propulsion systems based on a new approach.
    The systems that propel the spaceships (rotary or straight) which were developed on the basis of the old approaches to engines do not give astronauts even the slightest chance for comfortable conditions in extended missions. Acceleration of the spaceship followed by prolonged coasting flight is a not optimal option when minimal duration of flight is the objective. Weightlessness does not add optimism either. Half a day in weightlessness seems excessive but manned mission to Mars will probably be many months. Rotation of the spaceship is an additional waste of fuel, which is normally an unaffordable extravagance. Few astronauts dream of accelerating the spaceship on the first half of the way, and then braking it on the second half although it would mean a minimal duration of flight, and artificial gravity onboard as well. Today it is impossible because of the fuel mass limitation.
    Nevertheless, manned missions to Mars are under discussion more and more around the world. The president of USA has announced that the organization of such a mission will be one of the priority directions of USA policy in the area of deep space exploration. The European Space Agency has also begun to speak seriously about missions to Mars. China has announced their interest. In Russia, numerous variants of missions to Mars have been developed since the time it was known as the USSR. Many projects were born and died. The last vision of a Russian mission to the red planet was done at the beginning of the new millennium. The most serious development of the project was undertaken at the Keldish Institute.
    However, once again, the approach to the realization of all variants of such missions remains the same. Astronauts are doomed to long flight duration, weightlessness, and large vulnerabilities to failures in orientation and propulsion systems. The risk remains extremely high. Though, there are large numbers of enthusiasts who offer themselves as the participants of missions to Mars, and even are ready to fly only one way, knowing beforehand, that return to Earth may be impossible.
    There is an impression that the only role played by politics is the go-ahead and funding of such a mission. However, other important considerations are: the prestige of the nation, the economic impact of the project, and the publicity of the building and performance of the mission.
    During a flight to Mars the crew should not depend on reliability of engine injectors. The lives of the crew should not depend on leakage in the pipelines or the punching of holes in the fuel tanks by micrometeorites. The propulsion and orientation systems should be extremely reliable, providing a guaranteed return to the Earth. These systems are the only lifeboats for astronauts. Only such an approach to a manned mission to Mars will ensure achievement of the final goal without senseless risk (a variant of the Apollo-13 mission would not succeed in a mission to the red planet). The problem is not in the creation of a new approach to orientation or propulsion systems of a space vehicle, nor in the creation of new, revolutionary technologies, but in a system of relationships, which have been created between the companies, space agencies and governments. Breakthrough technologies for space applications are not necessary now. For any company that provides space services, the development of new technology creates a new set of difficult problems. First, traditional contacts with suppliers and subcontractors are broken. That results in the company becoming isolated due to its choice of a new, untraditional technology. It creates high risk in realization of the new technology. Some of the old companies drop out of the technological chain as a result of development of new technology. This process generates a significant resistance from these companies against innovation. In this case, the higher the level of breakthrough technology the more resistance because more companies who earlier participated in the sharing "of the space pie" will drop out of the field. In this case the resistance to the company daring to employ a new technology grows even more than number of the companies which have dropped out of space business. It is because companies now outside the field unite their efforts in a struggle with "the innovator of the technology". Therefore it is easier for a company to retain a certain and stable income rather than risk a confrontation with powerful industrial companies, which are connected closely with political circles. This factor, human relations, often determines policies of the company. This factor is stronger than financial rewards or technical benefits. All work is shared in this world. The first group of interested parties receives the income of production, the second group receives income from services and shows, the third group enjoys political benefits, and the fourth group gets the direct risk to life. The problems of the fourth and smallest group are not of interest to the three previous larger groups.
    Manufacture of space vehicles for deep space is not a well developed as the manufacture of cars yet, where great demand and intense competition are present. In the field of space, scientific and technical progress are out of tune with interests of the large business and big politics.
    Here is a pertinent example about Nikola Tesla. His car was propelled by a generator, which absorbed energy from the environment, but it was ahead of its time and was not needed by anybody. Therefore his breakthrough technology died at birth. Nobody could reanimate it until now, but probably nobody will. Today we have exactly the same problem with regard to breakthrough technologies for deep space exploration. There are no companies, which are interested in great new inventions and breakthrough technologies. For both companies and organizations it is much safer to be engaged in manufacture and modernization of their old technologies. Therefore, when a revolutionary new technology appears along with its new set of problems and pure technical risks, an interesting thing is unexpectedly discovered: nobody is willing to face the new set of problems. They instead prefer to struggle with old problems, and do it successfully for many years. The decision to go with a new technology means that whole auxiliary branches with large groups of people become unnecessary. But that is unacceptable from the point of view of the big companies and organizations. A struggle for a survival begins. It is not a struggle to speed up technical progress but against technical progress. As a result the breakthrough technologies are crushed before they start.
    From conceptual point of view, the task of Solar system exploration can be decided simply. Electrical energy is the only kind of energy, which can be generated in space for a long time. Out as far as Mars orbiting solar arrays can be used, but at the orbit of Jupiter and beyond, only nuclear fission can provide enough power. And then there is the biggest stumbling block of all. You have electric power but can convert it into motion only by ejecting fuel particles. It is imperative to take the next step. Only by direct conversion of electric power into kinetic energy can we really solve our problems in this area. If you have sufficient power resources, it is necessary only to carry out direct transformation of one kind of energy into another. In this case it means direct transformation of electrical energy into energy of rotary or linear movement of a space vehicle.
    This article does not have a purpose to unveil the zest of such engines but only to confirm above-stated. Time of these engines appearance in industrial scale is not come yet. The most difficult thing is not in inventing of something but in imbedding it into life.
    Let's analyze impossibility of appearance of engines for attitude control system as an example. The brief description of such an engine can be found by reference:
    el_motor 03engl.doc.
    All the vulnerable places of engines are obvious while analyzing the adjacent cells in a table "Advantages of the suggested system". Let's look through some items of the table only. All is interlaced very closely here.
    Let's analyze item 9 - "manufacture". Complicated manufacturing (Propellant and Oxidant - chemical industry, jet engines design - precision mechanical engineering) and the assembly of existing systems. Compare it with suggested. Companies involved into this space business will never allow attempts on the exclusiveness. The kings of fuel industry are watching over their interests and will not allow the situation that they can be superseded from the space market because of absence of need in fuel. Simplicity of the new system manufacturing is a mortal verdict for this system already.
    Let's go further. Item 11 - "Maintenance". It is necessary for anybody, to have a complex system check out for a minute? For example, when experts are "flying" around the system for the test of pipelines and tanks tightness so long-term and hard work "is visible". There is a reason to demand money from the customer.
    Item 12. "Material costs". If it is high, so a company receives high dividends while manufacturing of the space vehicle system. If the system appears simple in manufacturing, and manufacture is not repetition work, what for such system is necessary to the manufacturer? Plus inevitable risk to have a quarrel with the business partners, subcontractors, suppliers. The space agencies can not demand increasing of the budget. And the national program of deep space exploration seems frivolous if huge expenses are not required for its realization, and it is possible to reach it by essentially smaller sums.
    Thus, the advantages of new technology turn against occurrence of this technology. If the offered technology improves parameters of existing systems, for example on 5-10-15 of percents only but does not change the approach to the system itself, such technology could take a place in a history of engineering. If the appearing technology means qualitative revolution in engineering, so at once there is a conflict between dumb technique and interests of large groups of people. The victory remains behind the latter. The new technology can have the right for life when the appropriate conditions have appeared but not in present time. While it is so, Mars remains and will be still far, though and it seems close.



.
© ., 1997-2002. "". .
06.10.2002.