1960 5438+00 In June, the former Soviet Union launched a Mars probe twice, but unfortunately both of them crashed without entering the orbit of Mars.
1 962165438+1October1The former Soviet Union launched three more Mars probes, one of which lost contact with the Earth on the way to Mars, and the other two only stayed in the orbit of Mars.
1964165438+1On October 28th, the United States launched Mariner 4. 1On July 4th, 965, 1965 flew 9280 kilometers away from Mars. Mariner 4 successfully took 22 photos of the red planet at close range.
1971may19 and may 28th, the former Soviet union launched Mars 2 and Mars 3 probes successively. In the same year, 65438+February 65438+May, the former Soviet Union's "Mars 3" landed on Mars for the first time and sent data from the surface of Mars to the Earth for 20 seconds.
197 1 On May 30th, the United States successfully launched Mariner 9. 1 14 years 1 On October 30th, Mariner 9 entered the orbit about 280km away from Mars/kloc-0, and was in orbit nearly1. According to these photos, the United States first named the highlands, volcanoes, depressions and canyons on Mars.
1975 On August 20th and September 9th, the United States launched Viking 1 and Viking 2 respectively. 1On July 20th and September 3rd, 976, these two probes successfully landed on Mars in turn, and sent back a lot of new and valuable data and images to the Earth. Among them, "Viking 1" worked on Mars for 6 years, but failed to find any life features or traces on Mars during its two landings.
From the above facts, it can be seen that among these early Mars explorations, the most successful ones should be "Viking 1" and "Viking 2" probes in the United States. NASA launched these two pirate Mars River probes in 1975. After a year of interstellar travel, the probe finally successfully entered the Martian atmosphere and landed on Mars respectively. Scientists equipped with a large number of precision instruments on these two landers can analyze the soil of Mars, measure the air pressure, wind speed, temperature and other indicators on Mars, and determine the elemental composition of the Martian atmosphere. In order to detect whether there are signs of life on Mars, scientists specially designed some experiments. In these experiments, the probe first collected the soil samples of Mars with a robotic arm, and then analyzed the soil samples through experiments. It has been found that gas can be released from the soil of Mars. However, scientists at that time attributed it to chemical reactions.
1999, Joseph Miller, a neurobiologist at the University of Southern California who worked for NASA, asked NASA to re-study the experimental results more than 20 years ago. Because Miller firmly believes that in the data collected by the Viking Mars probe launched by NASA in 1975, there is evidence that there is life on Mars. However, due to the loss of relevant information, so far, NASA's research can only prove that there was a chemical reaction on the surface of Mars. Miller further pointed out that NASA lost the experimental data. Considering Miller's opinion, NASA thoroughly searched the information in the archives and finally found a computer record that had been neglected for a long time. Because this record uses an extremely old encoding format, no living designer can recognize this encoding program. Therefore, Miller can only rely on the data backup kept by NASA personnel to carry out his own research work. Those data are very few, just the original 1/3. Miller put the data together and analyzed them, and finally came to the conclusion that there is probably life on Mars. 2001165438+1On October 28th, he held a scientific seminar in San Diego, and Miller announced his research results to the world.
After entering the 1990s, due to the disintegration of the former Soviet Union, Mars exploration almost became a "patent" for Americans. During this period, the United States conducted many Mars explorations.
1On September 24th, 992, in order to investigate the geographical and climatic conditions of Mars, the United States launched the Mars Observer to explore the way for manned spacecraft to fly to Mars.
1996, the United States launched the "Mars Pathfinder" probe into space and sent back quite a few photos of Mars to the Earth. Three months later, the American "Mars Global Surveyor" probe entered the orbit of Mars and began to draw a map of Mars.
200 1 10 year1On October 29th, the American Mars probe "200 1 Mars Odyssey" made a lot of exploration achievements on Mars.
At the end of 200 1,1/at the end of the year, American scientists studied the new photos sent back by the Mars probe, and put forward the hypothesis that solid water (that is, ice) is likely to exist in some areas on the surface of Mars. The results of this study show that there was a vast ocean on the surface of early Mars, and there was even more water per square kilometer on Mars than on the earth.
Scientists at Brown University in the United States published an article in the British magazine Nature, saying that the Mars global probe is still flying around Mars and has sent back more than 8,000 high-definition photos to the Earth. After studying these photos, I found that there is a flat terrain. Scientists believe that this terrain shows that the soil layer in this area is porous soil frozen and solidified after water permeates, or water is mixed with ice, dust and rocks, forming a covering layer with a thickness of 90 cm on the surface of Mars. On the huge surface of Mars, there are such water-bearing areas in a large area from the cold south pole of Mars to about 60 degrees south latitude.
Although only hydrogen atom, one of the products of water decomposition reaction, has been found at present, this discovery is very helpful to infer the water content that Mars once had.
The study also shows that there was an ocean on early Mars, and its deepest depth could reach 1.6 km. Due to chemical reactions and the impact of asteroids and comets, Mars has gradually lost all its water in the past millions of years.
Researchers believe that water still exists in the depths of Martian soil or is frozen.
If this discovery can be confirmed in the future, coupled with other evidence of water on Mars, the credibility of liquid water and even simple life on Mars will be greatly improved. If humans can further detect sufficient water resources, it will be easier for humans to further explore Mars and even move to Mars.