Lunar exploration has promoted the development of lunar science, especially lunar geology. For the first time, human beings have a systematic understanding of the celestial bodies beyond the earth where we live, including physical characteristics, orbital parameters, space environment, surface structure and state, mineral rocks and chemical composition, internal material composition and so on.
Lunar exploration has also spawned some new disciplines, such as comparative planetology. A large number of detection data and sample analysis results make it possible to make a detailed comparative study of the earth and the moon, and extend it to the comparative study of limited detection data of other planets, which greatly deepens human understanding of other terrestrial planets. At the same time, because studying the earth on the earth will inevitably lead to "myopia", we need to study other planets and compare their similarities and differences in order to fully understand the planet where we live, so the scientific research of lunar exploration has also promoted the development of earth science.
2 1 century, lunar exploration will enter a new climax. During this period, apart from launching a lunar probe to further explore the moon, developing and utilizing lunar resources and establishing a lunar base will become an important goal of the new round of lunar exploration.
United States: Return to the Moon Plan In the 1990s, the United States launched two lunar probes, Clementine and Lunar Probe.
Clementine probe1994 65438+1On October 25th, the "Clementine" lunar probe was launched from vandenberg air force base by a Hercules rocket, and entered the lunar orbit on February 25th, 2000. The probe weighs 424 kg and is stable in three axes. It is equipped with ultraviolet/visible camera, near infrared camera, high resolution camera and lidar. Its main goal is to determine the optical imaging remote sensor and component technology needed by the next generation health of the US Department of Defense. The 6,543,800+800,000 Zhang Yue images it obtained prove that there may be water in the polar regions of the moon.
Lunar prospector1998 65438+1On October 7th, the lunar prospector was launched by Athena-2 rocket from Station 46, Cape Canaveral. This is the second lunar probe launched by the United States after the Apollo program. It uses spin stabilization mode, with a mass of 295 kg and an orbital height of 65,438+000 km. Its main loads are gamma ray detector, alpha particle detector, magnetic field instrument and Doppler gravimeter. The project will cost $59 million. Its main task is to measure the ice content in the cold and polar regions of the lunar crater and obtain information for establishing the lunar base in the future. It will also complete the determination of the chemical composition of the lunar surface and the mapping of the global magnetic field and gravity field of the moon. The data sent back by "Lunar Probe" is much more detailed than that of "Clementine", which is of great reference value for understanding the origin and overall structure of the moon.
On June 6+10/October 6+April 6, 2004, US President Bush delivered a speech at the headquarters of NASA, announcing a new space program, in which returning to the moon is the most important task. American astronauts will return to the moon as early as 20 15 and no later than 2020, and will establish a permanent base on the moon, taking the moon as a springboard to prepare for sending people to Mars or even more distant planets. In order to implement this grand plan, the United States will invest more than 200 billion US dollars to develop new launch vehicles, manned spacecraft and lunar modules.
Specifically, former President Bush's space plan includes completing the construction of the space station, grounding the space shuttle, returning astronauts to the moon and landing humans on Mars. This space program is ambitious, as Bush himself said, "I don't know where this trip will end."
For a long time, the American space community has been arguing whether the next goal of American manned space flight is to land on Mars or return to the moon. Although many people in the United States have a soft spot for Mars, there are great technical and financial difficulties in going to Mars. Obviously, it is much easier to build a space base on the moon than to land on Mars. First, the distance between the moon and the earth is very close. Facts have proved that people and goods can be sent to the moon by using the existing rocket technology, and there is no problem in communication between the moon and the earth. Secondly, the moon does not have the kind of sandstorm on Mars, and it is easier to land on the surface of the moon. Of course, the rich resources on the moon are also very attractive.
In order to achieve the goal of returning to the moon, the United States must redesign the space transportation system for landing on the moon. 1969 ~ 1972, the Apollo spacecraft system used by the United States in the mission to the moon was only designed for a landing and a short stay. The command module can only accommodate three people, while the lunar lander can only accommodate two people. Therefore, the United States must design a new generation of spacecraft called "crew exploration vehicle" by Bush. This spacecraft can transport a group of astronauts and a large number of materials and equipment to the moon. Obviously, it will be different from the original Apollo spacecraft and the existing American space shuttle. Another technical problem is energy. To build a space base on the moon, it is necessary to build a solar power station or a nuclear reactor. If the United States plans to send astronauts to Mars after 2030, it seems necessary to develop rockets using new energy sources, such as nuclear-powered rockets, to shorten the flight time of astronauts.
After mastering the basic technology of manned space flight through Mercury spacecraft and Gemini spacecraft, the United States spent $24 billion in 196 1 ~ 1972 to develop Saturn series launch vehicles and Apollo spacecraft, completed six missions to the moon, and put 65,438+. However, due to the lack of application targets, this costly plan can not be continued, and the United States has to turn to the development of near-earth space and the development of space shuttles and space stations. In this way, the "Saturn" series of rockets ("Saturn 5" has a low-orbit carrying capacity of 126 tons) and the relatively mature spacecraft technology developed in the moon landing program have not been further applied so far. In the process of developing the space shuttle and the International Space Station, although the United States has made many major breakthroughs in technology and achieved a lot of results in space science experiments, many people think that the cost is far greater than its scientific purpose and practical use. On February 1 2003, the American space shuttle Columbia crashed and died, which once again caused widespread controversy about the International Space Station. In this context, Bush's new space program can not only inspire national pride, but also correct the development direction of American space.
On September 19, 2005, the United States officially announced a new moon landing plan, costing 104 billion US dollars, which will use a new generation of space vehicles, including new launch vehicles, Apollo-like spacecraft and landers. If all goes well, American astronauts will land on the moon again in 20 18 (2020 at the latest).
The new manned spacecraft will combine the safe and reliable design and technology in the space shuttle and Apollo moon landing project, with better performance. The new launch vehicle will use the main components of the space shuttle, such as external fuel tank, solid fuel booster rocket and main engine, and be divided into two types: smaller manned rocket and larger cargo rocket, in which the cargo rocket is close to the Saturn 5 launch vehicle with a height of 109, which is used to transport goods to the surface of the moon and keep them as reserves. The astronaut's spaceship is named "manned exploration spaceship" and will be placed on the top of the launch vehicle. It looks like an enlarged Apollo, but its mass has increased by 65,438+0/2. It can carry six astronauts, orbit the moon for six months, and send four astronauts to the moon and stay there for four to seven days.
Russia pays attention to international cooperation. In the 1960s, the race to the moon between the United States and the Soviet Union, two space powers, left the Russians with painful memories of failure.
1958, the former Soviet Union completed the transformation of the rocket that launched the artificial earth satellite, enabling it to launch the lunar probe. At that time, some scientists suggested sending an atomic bomb to the moon and detonating it on the moon, so that astronomers all over the world could take photos of the explosion to show the technical strength of the former Soviet Union. But physicists believe that because there is no atmosphere on the moon, the time of nuclear explosion may be very short, and it is difficult for astronomers on the ground to photograph the explosion scene. Therefore, the former Soviet authorities rejected this proposal. Later, the former Soviet government turned its attention to manned landing on the moon, and began a competition with the United States for 10 years.
Like the United States, the former Soviet Union's mission to the moon was also intended to be completed with large launch vehicles and orbital complexes. The launch vehicle that landed on the moon was codenamed "N 1". 1964, the former Soviet government decided to send astronauts to the moon first before the United States. In order to accomplish this task, the scheme of "N 1" was modified several times from 1962 to 1966, the payload mass increased from the initial 50 tons to nearly 98 tons, and the number of first-class engines also increased from 26 to 30. In order to catch up with the progress, these engines were assembled and launched before the first launch, which led to a major launch accident. Due to technical problems and complicated design, the "N 1" rocket also ended in fiasco in subsequent launches, which led to the bankruptcy of the former Soviet Union's moon landing program. Later, Russian space experts summed up their experience and said, "This is an unfair competition. At that time, the United States was much richer than us, especially when the national strength of the Soviet Union was greatly weakened by the war and arms race with German fascists. From the beginning of the race to the moon, we knew we couldn't win. "
Now, in the new round of moon development upsurge, Russians begin to study the moon with a low-key and pragmatic attitude, give full play to their strengths, focus on developing the life support system of lunar rover and human long-term space navigation, and actively seek international cooperation in various space undertakings.
In addition to preparing to participate in India's lunar exploration program, the cooperation between Russia and the European Space Agency in the field of space development and commercial satellite launch has entered an important stage. By combining Russia's unique space technology with the technology and funds of the European Space Agency, it is possible for the brand-new six spacecraft "Clipper" to replace the manned spacecraft "Soyuz" 20 10 years ago. The new spacecraft can send people and goods to the orbital station, and if necessary, it can urgently withdraw astronauts and equipment to Earth. It can be used for automatic on-orbit flight up to 10 day and night, and also for scientific research purposes. In addition, Russia has strengthened its cooperation with Germany to study how astronauts can prevent space radiation, which is the most complicated and urgent task in the contemporary aerospace industry.
Russia has rich experience in manned space flight, so it is also possible to participate in the new space program of the United States, including the training of Mars explorers.
Russia's lunar exploration plan can be roughly divided into three stages: the first stage is 20 10 to 20 15, and the Soyuz series spacecraft are used to explore the moon; In the second stage, from 20 15 to 2020, astronauts will land on the moon, and a conventional lunar transport system will be established, that is, helium -3 will be transported from the moon to a space tugboat docked on the International Space Station by a new spaceship "clipper", and then the helium -3 will be transported back to Earth by this space tugboat that can carry 25 tons of cargo. The third stage will be from 2020 to 2025, when a permanent base will be established on the moon to develop helium -3 energy.
As early as 1994, the European Space Agency put forward a detailed plan for returning to the moon and establishing a lunar base. 1In May, 1994, the European Space Agency held an international symposium on the moon. It was agreed that the great development made by human beings in robotics, electronics and information technology made it possible for human beings to explore and study the moon at low cost. On this basis, the European Space Agency set up a steering group for lunar research, and proposed that lunar exploration and research should be strengthened in the future, including: launching lunar polar satellites to study and obtain high-resolution lunar geomorphological, chemical and geological images; A lunar station and robot system were established to measure the chemical and mineral composition of lunar rocks and collect lunar samples for ground research. From 2020 to 2035, it will be loaded on the moon and a lunar base will be established.
At 23: 00 GMT on September 27th, 2003, the European Space Agency successfully launched the "Wisdom 1" lunar probe from Kourou Space Launch Center in French Guiana, which was the first lunar exploration satellite launched by human beings in the 20th century. Although "Wisdom 1" is only a small satellite, its main purpose is to test a series of high and new technologies that will be used in future deep space exploration through lunar exploration practice, but it has already started a new round of lunar exploration climax.
The English name of "Wisdom 1" lunar probe is Smart- 1, which is the abbreviation of small missions for advanced research in technology, meaning small spacecraft to study advanced technology. As a deep-water bomb for European lunar exploration, "Wisdom 1" is like an elf flying to the moon. Its shape is almost cubic, and its size is1570x150x1040mm. The mass at launch is 370kg, and the wingspan of the solar wing is 65430. Due to the lack of total funds, "Wisdom 1" has adopted a large number of modular and universal designs, and its structure is compact. Many spare parts are purchased directly from stores, which is a masterpiece of miniaturization. It carries only 19 kg for many technical tests and scientific research.
"Wisdom 1" carries six kinds of scientific instruments, among which three sets of remote sensing instruments are used for lunar exploration. They are multispectral miniature cameras, high-resolution infrared spectrometers and small X-ray spectrometers.
The average resolution of the multispectral miniature camera is 80 meters, and the resolution at 300 kilometers near the moon is 30 meters (the spatial resolution of the American lunar probe is 200 meters). Through the high-resolution imaging of the polar regions, the shadow areas can be identified, and then the water ice in the crater can be found. In addition, the miniature camera also cooperates with the optical ground station on the earth to carry out laser communication experiments.
The infrared spectrometer divided 256 spectral bands in the range of 0.93 ~ 2.4 microns. Using these data, the composition of various minerals can be accurately determined. For example, pyroxene and olivine in lunar soil can be distinguished, which is very important for understanding the evolution of lunar shell materials. This infrared spectrometer was first developed and used by ESA. If it is successful in lunar exploration, it will be further used for future exploration of Mars, Mercury, asteroids and comets.
X-ray fluorescence is measured by a small X-ray spectrometer, so as to draw the elemental composition map of the lunar surface. Using these data, we can accurately calculate the composition of the lunar crust, study the structural characteristics of Antarctic craters, and draw the distribution map of lunar resources. This small X-ray spectrometer is also a necessary instrument for exploring Mercury and other planets in the solar system in the future.
"Wisdom 1" is also the first spacecraft in the world to use solar electric rockets as propulsion devices for long-distance flight.
According to the scheduled plan, the whole flight process of "Wisdom 1" is divided into four stages: launch and early orbit, earth escape, lunar capture and lunar observation. In addition to launching chemical rockets, other stages of flight, including early orbit, rely on solar electric rockets to provide thrust. This is its most prominent feature and highlight. However, due to the small thrust generated by the electric rocket and the slow acceleration, it takes much longer to enter the final flight state than the chemical rocket.
The solar electric rocket engine that provides flying power for "Wisdom 1" is strictly a solar vasimr. Xenon is used as the working medium, and efficient gallium arsenide solar panels are used to convert solar energy into electric energy, and then electromagnetic fields are generated. Xenon atoms are ionized by electric energy to form plasma, and xenon ion flow is ejected at high speed under the action of electromagnetic field, thus providing thrust for "Wisdom 1". This kind of solar electric rocket is 10 times more efficient than the commonly used chemical rocket, and it needs less propellant, that is, working fluid, so that the spacecraft can have more space to load payload. Because it uses inexhaustible solar energy, it can run continuously in space without gravity for several years. Its disadvantage is that the thrust and acceleration are very small, and it takes a long time to make the spacecraft reach the predetermined flight speed. Its significance lies in that if this flight test is successful, this propulsion system will be used in spacecraft with longer range in the future.
In order to master the actual technical performance of the solar plasma engine, an electric propulsion diagnostic module was installed on "Wisdom 1" to monitor the working condition of the propulsion system and its influence on the spacecraft. At the same time, it also carries spacecraft potential, electron and dust experiments, monitors the influence of propulsion system on electron flux, electric field and spacecraft potential, and studies the charged environment in the Earth-Moon space. In addition, it also includes advanced equipment such as laser communication technology between the earth and distant spacecraft and autonomous navigation computer technology of experimental spacecraft.
New technologies such as solar plasma engine and many detection technologies tested on "Wisdom 1" will have a far-reaching impact and important role on the future development of space technology in Europe and even the world if they are proved to have achieved the expected results. The main scientific instruments and their mission instruments carried by the European "Smart 1" target are mainly the electric propulsion diagnostic components, new technologies, experimental monitoring of propulsion system and its influence on spacecraft, new technologies of experimental monitoring of the influence of propulsion system on electron flux, electric field and spacecraft potential, research on the charged environment of Earth-Moon space, new technologies of deep space X/Ka band measurement and control test pieces, experimental testing of the next generation radio communication technology between high-speed flying Earth and spacecraft, and reception of X-band deep space transponder.
Not to be outdone, Japan put forward a plan to build a permanent moon base in 1996. It is estimated that in 2030, more than 26 billion US dollars will be invested to build a lunar base, including living quarters, oxygen and energy production plants and a lunar observatory.
Japan launched its first artificial satellite in 1970, and for a long time after that, Japan was in the forefront of the international space industry. After the successful flight of the scientific satellite Tian Fei around the moon, the confidence of the Japanese space community has greatly increased. 199 1 year, an ingenious lunar exploration plan was made, including the development and launch of probes such as "Moon A" and "Moon Goddess". From 65438 to 0994, Japan made a more ambitious plan: in 2024, it invested more than 26 billion dollars to build a six-person lunar base, including residential, oxygen and energy production plants and a lunar observatory.
"Moon A" was developed by Japan Institute of Space Science and weighs 540 kilograms. It is planned to carry two spear-shaped drilling devices with a height of 80 cm and a diameter of 16cm. After the satellite reaches the surface of the moon, the two drilling devices will be inserted into the surface of the moon, and the scientific instruments carried on the devices will transmit the detected data to the satellite and then back to Earth.
Design a lunar probe
1990 65438+1On October 24th, JAXA successfully launched the "Muse A" lunar probe (also known as the "Tian Fei" probe) with an M-3S2-5 rocket, and also equipped with a "feather suit" circulator. Due to the low separation speed of the star and arrow, the apogee of the detector is only 290,000 kilometers. "Tian Fei" orbited the moon 10, and the closest detection distance to the moon was 16472 km. It crashed into the moon on April 65, 1993 at 438+09 after the mission.
The satellite "feather" weighs 12kg and has a hexahedral shape. It is equipped with a 4kg solid motor for lunar exploration, and its solar wing can provide 10W power. The top of Feather is equipped with transponder and omni-directional antenna for data transmission and measurement and control. It was originally planned to be released in March 1990 and 18, when the Tian Fei probe first arrived near the moon. However, due to the failure of the transponder, the "feather" could not be released and the detection work could not be carried out.
Goddess of the moon
On September 14, 2007, Japan successfully launched the Lunar Goddess probe with H-2A rocket, and carried two sub-detectors, namely relay star and very long baseline interference star. The two sub-detectors were successfully separated. The "Goddess of the Moon" weighs 3,000 kilograms, with a design life of 1 year and a height around the moon of 100 km. * * * Carry 65,438+05 detection instruments, such as X-ray spectrometer, gamma-ray spectrometer, multi-band imager, spectral profiler, terrain camera, lunar radar detectors, laser altimeter, lunar magnetometer, charged particle spectrometer and plasma analyzer. The two sub-detectors, each weighing 50 kilograms, are responsible for the communication and transmission between the detector and the earth, as well as the accurate measurement of the position and movement of the moon.
The "Moon Goddess" lunar exploration program is the largest and most complicated since the American "Apollo" program. Japanese scientists hope to know the composition and mineral composition of the lunar surface, the structure of the lunar surface, the gravity field, the magnetic field, the high-energy particle environment and the plasma area of the moon through the instruments they carry with them. Through the above research activities, I hope to further uncover the secrets of the origin and evolution of the moon.
The "Moon Goddess" detector program is jointly implemented by the Japan Space Development Agency and the Japan Institute of Space Science. The main goal of the plan is to solve the key problems necessary to explore the solar system, especially the soft landing and data relay technology. Japan called "Moon Goddess" the first step of Japan's future lunar exploration plan, which will lay the foundation for Japan to establish a manned lunar base in 2024.
At present, Japan has done a good job in lunar robots and accumulated rich technical experience. The Japanese Institute of Cosmology and the University of Tokyo have successfully developed a lunar mole detection robot. Its shape is a cylinder with a diameter of 10 cm and a length of 20 cm. Like a mole, it can drill into the underground of the moon 1 1 m, collect minerals and analyze them to find out the structure of the moon surface. It has two devices, namely, a sand discharge device and a tunnel device. The sand discharging device has two rotating rollers, which can roll the dug sand firmly. The digging device pushes the piston against the rolling sand and pushes the car body forward with the piston. The researchers' next task is to make the lunar ground supporting equipment. The designed ground equipment is 20 ~ 30 cm in diameter and equipped with solar cells. In addition to supplying power to the robot, the lunar ground equipment is also responsible for receiving the detection data of the robot and sending signals to the earth.
India: the terrible afterlife
With the help of Russia, India will realize the "Yuechuan-2" moon landing plan from 20 1 1 2 to carry out lunar surface exploration.
India's space industry started from 1962, and after more than 40 years of development, it now occupies an important position in the world's space countries. In terms of lunar exploration, India is not far behind.
At the end of 2003, a cryogenic rocket engine fueled by liquid hydrogen and liquid oxygen designed and manufactured in India successfully burned 1 0,000 seconds in the ground test, exceeding the minimum requirement of 72 1 second required for space flight. The success of this test makes India the sixth country in the world capable of making its own cryogenic rocket engine after the United States, Russian, French, China and Japanese. With the great progress of the cryogenic engine developed by India and the advanced satellite remote sensing technology in the world, India's technology of implementing the lunar exploration program has matured.
It was also in this year that India launched the lunar exploration program. Code-named "Moon Ship" (namely "Moon Chu Hang 1"), it is planned to launch a moon-orbiting satellite weighing1050kg in 2007, at a cost of 85 million US dollars.
India's moon-orbiting satellite will be launched by India's polar-orbiting satellite launch vehicle, and will eventually run in the polar orbit at a distance of 0/00 km from the moon/kloc-to probe the surface of the moon for two years. The main tasks are to draw topographic maps, analyze chemical composition and investigate mineral distribution.
Indian scientists are now stepping up the development of 32-channel spectrometers, low-energy and high-energy X-ray spectrometers, solar X-ray spectrometers and laser altimeters. In addition, the synthetic aperture radar for measuring polar water ice will be developed by the Applied Physics Laboratory of Johns Hopkins University. In order to receive the signal from the lunar probe, India is building an antenna with a diameter of 34 meters. Experts from TT&C Center of Indian Satellite believe that the 25-meter-diameter antenna is enough for India's lunar exploration mission, but it must leave room for future deep space exploration missions.
20041From October 22nd to 26th, the 6th International Conference on Lunar Exploration and Application was held in India. India has not only attracted the world's attention with its own lunar exploration program, but also proved to the world with brilliant space achievements that India is becoming a space power with global influence.
On July 29, 2008, NASA announced at its headquarters in Washington that the United States had signed cooperation agreements with India, South Korea, Japan, Canada, Britain, France, Germany and Italy to jointly carry out lunar exploration activities.