Unlike planets, comets move on highly elongated orbits, and therefore are visible only at short periods close to the Sun.
The main part of any comet is its nucleus .
According to the hypothesis of the famous American researcher of comets Fred Lawrence Whipple, cometary nucleus is an ice consisting of a mixture of frozen water and frozen gases interspersed with refractory rocky and metallic particles . Figuratively speaking, it looks like a “dirty iceberg”.
Let us imagine that we see the newly opened the comet, which is somewhere in the vicinity of Jupiter’s orbit. Seeing through the telescope hazy pale speck, like a spherical nebula (such unattractive are presented to the observer of a distant comet), we may be disappointed at first. With the approach of the comet to the Sun the solar flux increases. Comet “ice” begin to evaporate rapidly. Around the nucleus formed a vast glowing gas shell – coma. Together with the core of it is the head of the comet. Continue reading
Radiation risk for astronauts (radiobiological rationale)
The book covers a fairly wide range of materials concerning the sources of cosmic rays affecting astronauts in the implementation of interplanetary and orbital space flight, the quantities of the doses, the reactions of individual systems and the whole organism of animals and humans, and changes its stability when the complex character of radiation exposure in space.
The results of a 14-year experiment on a large lot dogs with simulation values of the doses and nature of dose distribution in time, which will affect astronauts during the flight to Mars. The considered models of formation of radiation damage in the hematopoietic system and the level of the organism during long exposures with varying dose rate, and the model of radiation mortality rate of mammals, describing accelerated aging and the changing age-specific mortality rates in a dose-and dose rate radiation exposure.
The book presents the algorithms and results of calculations of the radiation risk in the process of interplanetary and orbital missions throughout the life of astronauts, as well as data on possible sacramentoa life expectancy. The new approaches to the regulation of radiation exposure and justifies the new lower acceptable dose to astronauts during flights and during the whole professional activity. Continue reading
By the end of XX century the mankind will be able to send a manned expedition to the planet Mars. The Soviet Union, the United States and other countries could combine resources to implement joint flight. In 1969 was declared a long-term program of the Soviet Union in the field of manned flights in which was planned the creation of orbital stations and laboratories with departing crews as the primary means of extensive exploration of outer space. They will be the “spaceports in space,” launch pads for flights to other planets. There will be large scientific laboratory for research into space technology and biology, medicine and Geophysics, astronomy and astrophysics.
Academician B. N. Petrov, at that time Chairman of the Council at the USSR Academy of Sciences on international cooperation in the exploration and use of outer space “Intercosmos”, noted that orbital space platforms will carry out the final Assembly of the spacecraft systems to conduct training classes of astronauts, which will be used to space conditions and to participate in the Assembly and testing of interplanetary ships.
In the Soviet Union there is a program capable of deducing in space of the modules of spacecraft and build space stations in earth orbit. Continue reading