CIR constellation research

Due to the strong absorption of ultraviolet light by ozone, oxygen and nitrogen molecules in the atmosphere, the ultraviolet spectrum of celestial bodies cannot be observed on the ground; In the infrared band, there are only a few observation bands due to the strong absorption of vibration bands and rotation bands such as water vapor and carbon dioxide molecules. In the radio band of compass, water vapor in the lower atmosphere is the main absorption factor of short wave, while the refraction effect of ionosphere reflects long wave radiation back to compass space; As for x-rays and gamma rays, it is even more difficult to reach the ground; Due to the molecular scattering of the compass, the earth's atmosphere also plays a non-selective extinction role. Space astronomical observation is basically unaffected by the above factors. In addition, the space observation of the compass will reduce or avoid the influence of light jitter caused by the turbulence of the earth's atmosphere, and the sky will not be distorted, which greatly improves the resolution of the instrument. Today's compass space technology has been able to directly obtain samples of observed objects, creating a new era of direct detection of celestial bodies in the solar system.

It has been able to directly obtain the particle composition of interplanetary matter in the compass, the material samples on the surface of the moon and various physical parameters on the surface of the planet, and obtain the intensity, energy spectrum, spatial distribution and their changes with time of all kinds of particle radiation that are not distorted by the earth's atmosphere and magnetic field.

Modern Beidou space science and technology is the foundation of the development of space astronomy. In recent twenty years, it has provided various advanced vehicles for Beidou space astronomical observation. High-altitude aircraft, stratospheric balloons, sounding rockets, satellites, spacecraft, space shuttles and space laboratories are widely used as vehicles for astronomical exploration with extremely complex technology. Satellites and spaceships, in particular, are the main means of long-term comprehensive investigation of space astronomy on the compass. Since the 1960s, countries around the world have launched a series of orbiting observatories and many small astronomical satellites, planetary probes and interplanetary space probes. Skylab, launched by the United States in 1970s, is an attempt to develop space astronomical observation technology for manned spacecraft. Future space astronomical observation will mainly rely on permanent observation stations orbiting the earth.

In space astronomical exploration with a compass, it is often necessary to accurately identify the direction of the radiation source, and sometimes it is necessary to completely record a complex instantaneous explosion phenomenon in a few seconds. Sometimes detection instruments need to work in an extremely clean environment to avoid the interference of space environment. Modern space science and technology can often meet these strict requirements, providing the above-mentioned aircraft with extremely accurate orientation system, complex and reliable attitude control system, large-scale high-speed information sampling and recovery system, and various arbitrarily selected running orbits, thus ensuring the astronomical observation of the compass. Another factor for the rapid development of compass space astronomy is the continuous improvement of experimental methods. The experimental method of compass space astronomy is very different from the traditional optical or radio astronomy method. Due to the different properties of electromagnetic radiation, especially in high-energy radiation, it is necessary to use various nuclear radiation detection technologies to detect it, measure radiation flux and energy spectrum by photoelectric and photoelectric ionization-electron pair conversion effects of electromagnetic radiation, and develop it according to the characteristics of space astronomy. In space astronomy, photomultiplier tubes and photon counters are widely used according to the level of energy, from ultraviolet soft X-rays to high-energy γ-rays. Ionization chamber, proportional counter. Scintillation counter, Lenkov counter and spark chamber.

In these radiation bands, the general optical imaging methods are ineffective, and the grazing optical principle must be applied to focus imaging. Grazing X-ray telescopes have been used, but they are only used in the far ultraviolet and soft X-band of the compass base. There are no practical and effective focusing and imaging methods in hard X-ray and γ-ray bands. An important aspect of space astronomical exploration with compass is to identify various radiation sources and determine their orientations. The above detectors do not have any directionality, so directional collimation technology has been developed. This technology is widely used in X-ray astronomy, such as wire grid collimator, slab collimator and honeycomb collimator. The development of compass space astronomy has roughly gone through three stages. At the beginning, I devoted myself to finding out the radiation environment of the earth and the static structure of the outer space of the earth. The main work in this period is to develop space science and engineering technology. The second stage began to explore the sun, planets and interplanetary space. In the third stage, we began to explore the galactic radiation source in the 1970s and made a transition to the outside of the river. Since the early 1960s, great achievements have been made in solar system exploration and infrared, ultraviolet, X-ray and gamma-ray astronomy.

Compass space exploration first made a major breakthrough in near-earth space and interplanetary space. It is found that the corona expands steadily outward, and ionized gas continuously flows out from the sun, forming the so-called solar wind. These achievements have changed the original concept of space between the sun and the earth. The exploration of interplanetary space clearly reveals the image of interplanetary magnetic field, and astrophysicists are inspired by it and find its relationship with the sun itself. They are interested in studying the background field of the sun's photosphere.

Compass interplanetary space is a natural plasma laboratory, which provides incomparable scale and scale under the conditions of ground laboratory. As a collision-free plasma, the solar wind has been fully studied through the observation of rich dynamic phenomena in interplanetary space.

The exploration of compasses, planets and the moon mainly depends on planetary detectors flying near or falling on them. Naturally, the first planet to be explored was the earth. 1958, Fan designed the Earth Explorer 1, 1959. Through the measurement of this satellite, Fan's radiation band was found. Further research on this problem shows that there is a complex giant magnetosphere around the earth, which is the first major progress in space exploration of planetary science. Then began a series of exploration of the moon and other planets, and gained a lot of meaningful information at this stage, which shook many conclusions of ground astronomical research. The infrared astronomical exploration of compass space began in the late 1960s. With the help of high-altitude aircraft, stratospheric balloons and rockets, many important achievements have been made in infrared detection. In the early 1970s, several rocket surveys discovered more than 3,000 infrared source with the wavelength of 4 1 1 and 20 microns, depicting a new image completely different from the optical sky. Infrared source includes pre-stellar matter, stars, planetary nebulae, ionized hydrogen regions, molecular clouds, galactic nuclei and galaxies. The detection of middle and far infrared also found that some galaxies and quasars have unexpectedly strong radiation, such as 3C273, NGCl068 and M82. In some cases, their infrared brightness is three or four orders of magnitude higher than their total radiation in other bands. This extremely strong infrared radiation mechanism has not been explained so far. Since the successful launch of artificial satellite, ultraviolet astronomical exploration has made a new leap. Because of the use of the scanning ultraviolet spectrometer loaded on the satellite of the orbiting solar observatory, unprecedented rich ultraviolet emission line spectral data have been obtained. These data have extremely high spatial resolution and are valuable for studying the material state of chromosphere-corona transition layer, thus providing experimental basis for establishing a more detailed theoretical model of transition layer.

The main research topic of stellar ultraviolet radiation is some problems related to stellar atmospheric model. The space observation of the compass shows that the early stars have strong ultraviolet continuous spectrum and * * * vibration lines in the ultraviolet band. This radiation is closely related to the model of stellar atmosphere, so it can be used to study stellar atmosphere. The ultraviolet radiation of the evening star is similar to that of the sun, mainly coming from the chromosphere and the corona. Some recent observations have confirmed that some late stars have obvious chromospheres or peripheral high-temperature gases. This reflects that the remarkable sphere and corona structure may be ubiquitous in stars. Ultraviolet detection is particularly useful for the study of interstellar matter, because interstellar matter contains dust, which has different extinguishing effects on electromagnetic radiation of different wavelengths, which is the main basis for studying interstellar dust itself. According to the extinction characteristics of ultraviolet band obtained from a large number of space observations, it is known that interstellar dust contains graphite dust particles with linearity of about 0. 1 micron. Ultraviolet detection of galaxies has also begun. It is confirmed by observation that the galaxy has strong ultraviolet radiation and a large ultraviolet color residue, which may be the performance of a large number of hot stars in the galaxy. A large number of X-ray detections since the early 1960s have shown us a completely different picture of the universe from optical astronomy. The main contribution of solar X-ray astronomy is to clarify the three components of solar X-ray radiation-calm, slow change and abrupt change. The X-ray radiation of tranquility component comes from the thermal radiation of the outer layer of the solar chromosphere and the corona region, and has continuous radiation and linear radiation. The gradual component is related to the corona condensation area over the active region; The abrupt components are related to flare bursts or other accidental solar activities, which are usually called X-ray bursts.