Looking for extraterrestrial life

The vast universe has many unknown things that have not yet been discovered. Although the earth is the hometown of human beings, with the continuous increase of the population on the earth and the gradual lack of non-renewable resources, it is increasingly difficult for the earth to carry the needs of so many people. Humans living on the earth may one day fly to other distant planets in search of a new home. However, in the sea of ​​thousands of stars, apart from the earth, are there really any planets suitable for human habitation?

For a planet to be suitable for human existence, it must have the basic conditions: like the earth, the received star (sun) has stable light and a suitable temperature; there is liquid water to provide a basis for life; there is a satellite (the moon) to resist asteroids Attacks ensure the stability and safety of the planet. The volume and mass are moderate; there is an atmosphere on the surface, and the cycle of day and night is relatively moderate; the composition of the atmosphere is suitable for human breathing; the activities of the planets cannot be too active, such as volcanoes and earthquakes.

The above are just the most basic living conditions, but few planets can fully meet such harsh conditions, but there are still very few planets that give humans a glimmer of hope.

Scientists have discovered that the formation time, internal structure, and even the initial environment of Mars are very similar to the Earth, just like Earth’s “twin brothers.” So, can Mars become the second home for human survival?

Based on what we know about Mars now, to go to Mars, Earth people must wear a sealed space suit to protect them from harmful ultraviolet rays. Because the air on Mars is thin, solar radiation is strong. At the same time, you need to bring an oxygen cylinder, because the atmosphere there is mainly composed of carbon dioxide, and the pressure is only 1% of the earth. There are clouds on Mars, but they are much thinner than clouds on Earth. The air on Mars is dry and the average temperature is below 0 ° C. Even at the equator, the temperature during the day is rarely higher than the freezing point; at night, the temperature will suddenly drop to about -100 ° C. The surface of Mars is barren, dust storms are frequent and violent, and it can even cover the entire planet.

So, will life exist in such an environment? Finding life in the solar system is actually looking for the potential to cultivate life. This potential may come in the form of simpler organisms, such as microorganisms, but this often also becomes a necessary condition for finding life. In the most basic process of creating and sustaining life, liquid water is necessary. The presence of liquid water becomes a direct condition for us to assess whether a planet or other celestial body is habitable.

In science fiction movies, the Mars scenes outlined are all dusty and weird, so is there water on Mars? Although NASA has discovered an underground lake on Mars, it has been determined that there is water on Mars, and that Mars’ air also contains oxygen, but these do not mean that Mars has life, or that humans have Can survive on Mars. This has also led scientists into confusion.

At present, except for a small number of Martian meteorites for scientists to study, humans can only use spacecraft for remote sensing and in-situ detection.

Although humans have found organic matter in Martian meteorite and detected methane in the atmosphere, is there still life on Mars? Has life ever multiplied on Mars? These questions remain unanswered. To answer these questions, hope can only be placed on the study of Mars samples.

Therefore, scientists have been hoping to collect samples from Mars for research in order to reveal Mars’ past and present life. After years of incubation, Mars sampling is finally about to be implemented.

“The Mars sampling mission will be one of the most important missions in space exploration,” said Andrew Coates, a space scientist at University College London in the United Kingdom.

Researchers say they now have a hard time predicting exactly how these samples will be studied in a decade, but they hope to find signs of life on Mars past or present.

Of course, scientists will not abandon research if no signs of life are found in the samples. They want to know why, because Mars is not livable, or because life hasn’t happened yet?

Scientists believe that billions of years ago, as the core cooled, Mars lost its magnetic field, the atmosphere escaped, the surface of Mars became cold and dry, and was “eroded” by powerful space radiation. By collecting different samples, measuring the ancient magnetic field of Mars, and studying the environment in which they were formed, scientists can verify whether the above theory is correct. If this is true, is it because Mars formed an uninhabitable environment long ago that life has never started?

In order to better understand Mars, humans have really exhausted their minds. “Curious”, “Insight”, and those Mars rover, lander, etc. who will visit Mars one after another on Mars sampling missions, “You sing me on stage” on Mars, adding a bit of liveliness to the desolate and lonely Mars And hustle and bustle.

As the world ’s interest in Mars exploration increases, more and more spacecraft will land on Mars. Taking the Martian launch window in 2020 as an example, there will be Mars rover launches from the United States, India, the United Arab Emirates, and the European and Russian “Mars Space Creatures” (ExoMars) program; and China’s Mars probe will also launch And will perform missions such as orbiting Mars, landing on Mars, and a rover inspection.

Mars Rover: Humans are looking for a home on Mars

Wu Qinying, Nanjing Zhizhi Experimental Primary School

(Wu Qinying, an outstanding young teacher in Gulou District, Nanjing City, has repeatedly undertaken municipal and district-level public classes and lectures; concurrently served as the school’s science and technology counselor, organized students to participate in various scientific and technological activities and competitions, and the team led many awards, won “Technical Counselor” title.)

Hello everyone, I am the Mars Rover, and call the engineer team I made “Mars One” because I am the first Mars Rover independently developed in China. And in July of this year, I will depart for Mars and land on the surface of Mars.

On October 11, 2019, I made my debut for the public. Since then, engineers and scientists have never stopped my research tests, such as the lander hover obstacle avoidance test on November 14, 2019. These tests are all to ensure that I can successfully land on Mars.

To me, going to Mars is not a journey that can be said to go. So, for this trip, I did enough.

First, choose the right transportation. That’s right, the Rockets.

The rocket that will carry me to heaven this time is the “Long March 5”, which is commonly known as “Fat 5” because of its large size. Although “fat”, its take-off thrust can reach the dry tonnage level, and it can easily break through the gravity of the earth.

My flight path is special. After “Fat Five” carried me to the sky, it accelerated near the earth and took me into the Hohman transfer orbit. This is an elliptical orbit with the sun as the focus. I was traveling in this elliptical orbit faster than Mars orbiting the sun, “flying” and waiting for Mars. When Mars is getting closer and closer to me, when we are about to meet, I will slow down near Mars and be captured by Mars’ gravity. The flight time of a deep space spacecraft from Earth to Mars orbit through the Homan transfer orbit is fixed. Therefore, when the spacecraft is launched, the relative position of Mars and the Earth must make the spacecraft reach the far point of the Homan transfer orbit. Mars could just be there waiting for the spacecraft to arrive. Such launch timings only occur about every 26 months.

The launch window for my trip was this July. So, when can I reach Mars?

This time can also be calculated by simply dividing the distance by the speed, because I don’t keep moving at a constant speed. My orbit is about 200 million kilometers. This distance is more than 500 times the average distance between the earth and the moon! I also need to go through acceleration and deceleration stages on this track.

The first probe to land on Mars was the American spacecraft “Viking 1”. It took 304 days from Earth to Mars. However, this was in 1975, and the engine used today is much more advanced than it was then. After calculation by scientists, after I left the rocket, it would take about 7 months to drift in space before being captured by Mars’ gravity. By that time, the earth has entered 2021.

The journey is long, but this is not the hardest part! Next, the orbiter will remain in Mars synchronous orbit and continue to orbit, and my lander will separate from it and prepare to land on the surface of Mars. From the moment I entered the Martian atmosphere to the landing on the surface of Mars, this process, although only 7 minutes, was the most difficult part of the entire Mars exploration. To ensure that I can land safely and smoothly on Mars, scientists have designed four key steps for me:

The first step is to reduce the aerodynamic shape. My appearance allows me to generate enough resistance when entering the thin atmosphere of Mars, and I will not overturn, bump, or fly backwards.

The second step is to slow down the parachute. I am equipped with a fully automatic parachute that will automatically open when decelerated to a certain degree.

The third step is to slow down the power. The engine I carry will start at the right time in the opposite direction of the movement, generating reverse thrust to myself, so as to achieve the purpose of deceleration.

The fourth step, when running to about 100 meters from the surface of Mars, my speed should be reduced to relatively zero, enter a hovering state, use the relevant equipment and equipment carried by the detector to select the landing area below, and try to find A relatively safe place to land. When it is one or two meters from the surface of Mars, I will activate a landing recoil device, commonly known as the “landing leg”, and rely on it to reduce the vibration force that I generate when landing.

These links are very meticulous, but the entire process can only rely on my own system to autonomously execute the commands set in advance. If I encounter an unforeseen situation and want to take urgent measures to communicate with the earth, it is too late.

The distance between Earth and Mars is so long that it takes nearly 23 minutes to travel one way at the speed of light. In other words, sending commands from the ground, I on Mars will not be able to execute until 23 minutes. Therefore, the actions during the landing must be performed by myself. All the actions add up to about a thousand!

I am really too hard! However, if I can land safely at that time, I will be one step to achieve the “round, land, and patrol” project goal, it is really worth looking forward to! Students also remember to cheer for me!