Foreword: Previously, I thought about it in "The Eternal Toss". Human life is limited, and maximizing one's own value is the most effective way to live. With this thought in mind, I have recently been concentrating on thinking and reading a lot of content, books, and even audio-visual materials related to extending the value of life. Recently, I saw a story about "Robots Exploring Mars for 15 Years". I was touched by the spirit of this story and would like to share it here. This article is compiled from online information.

The origin of the story, the United States’ exploration of Mars.

The United States has been exploring outer space for decades after World War II. I didn’t read the history of space in depth, so I couldn’t feel its greatness. Until the past few years, my country’s Tianwen Mark, After various technological capabilities caught up, I looked back at the history of outer space in the United States, and I discovered that the American spirit of exploration is actually worth learning.

From 1961 to 1972, the United States achieved six lunar landings through the Apollo missions. The Apollo missions are also hailed as epoch-making projects in the world's aerospace history. For all human beings, a successful moon landing also makes us a new "interplanetary" species.

Soon after the United States successfully landed on the moon, it began to set its sights on Mars. However, Mars exploration is obviously a more difficult task than moon exploration. This can be understood from the record of the Soviet Union VS the United States at that time.

Judging from the list of human Mars missions compiled by NASA, the United States and the Soviet Union are the countries that have explored Mars the most, and the United States is also the country with the most successes, but it is also the country with many failures.

The United States successfully launched the "Mars Odyssey" probe in 2001, which for the first time discovered the existence of water ice beneath the surface of Mars, indicating the possibility of life on Mars.

"Mars Odyssey" is still conducting scientific exploration and providing communication relay for landing missions on Mars. It is the longest "service life" among the current Mars probes.

In 2003, the United States' second-generation "twin" Mars rovers "Spirit" and "Opportunity" were successfully launched one after another.

Compared with the first-generation Mars rover, the performance of the second-generation Mars rover has been greatly enhanced, enabling a larger range of mobile surveys of Mars.

"Spirit" and "Opportunity" discovered evidence that water once existed on Mars, and also allowed scientists to obtain detailed information on hydrological activities in Mars' history.

And it was this exploration story that attracted me, and I especially went to learn the ins and outs of this journey to find water on Mars.

Act 1: The mission is arduous, and the mission is in danger

Mars is the most suitable planet for development in the entire solar system except the Earth. Human beings also began to explore it as early as the 1960s, but in the early The failure rate of detection was very high, and the Soviet Union did not even achieve a real success until its disintegration. After experiencing the madness of the Cold War in the 1960s and 1970s, human Mars exploration came to an abrupt end and did not restart until the 1990s. Unfortunately, the Mars Observer (1992) launched by the United States failed, and the Mars 96 (1996) launched by Russia also failed after launch.

It was not until 1996 that the American Global Surveyor ushered in success. It was accompanied by the Pathfinder lander/Sojourner Mars rover, and the little Sojourner was also there. In 1997, it became the first human rover to successfully land on Mars. Compared with landers that can only land at fixed points, Mars rovers have a huge advantage: they can move, which is enough to illustrate their value. But it was too small, weighing just over 10 kilograms, and the instruments it carried could not have complex functions. The mission was declared over after only working for dozens of days. Humanity urgently needs a comprehensive, complex, and multifunctional rover to land on Mars.

Under this demand, NASA's Mars exploration plan officially established the Mars Exploration Rover (MER) project, which includes two Mars rovers weighing 185 kilograms, MER-A. and MER-B, both are identical and backup each other. Unexpectedly, two U.S. missions to Mars in 1999 faced disaster again: the Atmospheric Prospector orbiter burned directly in the Martian atmosphere, and the Polar Lander crashed only 40 meters from the surface. Under this circumstance, the pressure on the two Mars rovers to complete their missions can be imagined. The cost of failure has once again plunged human Mars exploration into a low ebb.

Act 2: Have the courage to seize the opportunity

Fortunately, the Mars Odyssey orbiter launched in 2001 was a great success and can provide low-power ground-based The rover provides signal relay, which means that the two- rover mission can successfully embark on its journey in 2003.

Therefore, the two twin brothers of the Mars rover were finally named Spirit (MER-A) and Opportunity (MER-B).

In fact, they still have two "cousins" left on the earth for testing. One of them is almost exactly the same as their scientific instruments, structure, and weight, and is used to test the working conditions of each instrument; the other is lighter and almost useless. The instruments carried are only used to simulate the impact of weight on the body structure under the gravity of Mars.

The two probes successfully launched aboard the huge Delta 2 rocket on June 10 and July 7, 2003 respectively. They adopted a long Hohmann transfer orbit of more than 200 days to go to Mars. , and arrived in January of the following year.

Act Three: Seven Minutes of Death and Airbag Bounce

Landing on Mars is never easy. Mars has a lower gravity than Earth and has a thin atmosphere, but it can be decelerated using a combination of air resistance friction and a further parachute just like landing on Earth. Due to the fast speed, friction can generate huge heat that will continue to accumulate on the surface of the probe, reaching an astonishing 2100 degrees Celsius (during the landing of the Curiosity Mars rover). However, the Martian atmosphere is too thin, less than 1% of the Earth's. Its deceleration effect is limited, so it is impossible to use a parachute to complete the final deceleration like the Earth.

In addition, Mars is closest to the Earth at the level of 50 million kilometers, which already means a round-trip communication delay of nearly 6 minutes. In fact, the obstruction caused by the rotation of the two must also be considered, and the actual time is much longer than this. The entire landing process cannot be completed by manual control and monitoring on Earth. From the time the probe enters the edge of the Martian atmosphere to the final landing on Mars, there are only about 7 minutes, and you must rely on yourself. Although the landing time is short, there are thousands of operations that need to be performed independently throughout the entire process. Problems in any link will lead to failure. For example, on October 19, 2016, the ESA Schiaparelli lander failed at the last moment during its mission and crashed directly into the surface of Mars and was shattered to pieces. Otherwise, its landing site will also be the Meridian Plateau where the Opportunity rover is located. If successful, they will become partners fighting side by side. It’s just that the result is extremely regrettable!

After atmospheric deceleration and parachute deceleration, the detector landing device must use reverse thrust rockets to work. However, the built-in reverse thrust rocket will cause the bottom of the probe to be occupied by huge fuel tanks, engines, sensors, etc., which will become dead weight once it lands, making it very unsuitable for a Mars rover that should move freely to perform missions.

The final option for Spirit and Opportunity was the airbag bouncing method: after the parachute detached, the rocket reverse thrust method was still used to decelerate and hover to determine the landing site. However, at this time, the lander was divided into two parts. One part carried the recoil rocket and fuel tank, and the other part folded the rover and tightly wrapped it in a huge air bag. After the lander determines the landing area, it will eject the air bag and hang it firmly with a rope. After the steady descent command is issued, the rope breaks. The airbag was released a few meters above the Martian surface and then stabilized after bouncing several times on the ground. There is often a balancing device inside the huge airbag to ensure that the folded rover maintains the correct posture with the ground after the airbag stops. Then the airbag opens and the rover slowly unfolds and drives out. This technology has been successfully verified during the Pathfinder mission.

Act 4: The slow-moving Mars "rover"

In order to become a mobile rover, Spirit and Opportunity must be equipped with additional power, imaging and navigation systems. This basically does not exist in fixed-point landing missions. Both probes are powered by two solar panels on their backs. They used the most advanced multi-junction solar photovoltaic cells on earth at the time, which could absorb and utilize energy in multiple spectrums of the sun. However, since the solar energy on the surface of Mars is far less powerful, The earth is rich and the atmosphere is full of dust. Under the best conditions, solar energy can only provide 900 watt hours of energy per day, which is less than one kilowatt hour of electricity. On average, the working efficiency is generally at the level of half a kilowatt hour of electricity.

When a global sandstorm breaks out on Mars, the yellow sand in the sky will drastically weaken the sunlight and adhere to the surface of the solar panels, so that the daily production capacity is only 100 watt hours of energy, and the Mars rover must enter sleep. state. Even at 900 watt-hours in the best weather and at peak times, this energy can only keep an average water heater on Earth running for half an hour, and can only keep an old 40-watt light bulb on for a day. In order to make full use of energy, especially to avoid no energy source at night, two 7-kilogram lithium batteries are also carried on the rover to store energy.

Considering that these two Mars rovers are behemoths with a height of 1.5 meters, a width of 2.3 meters, a length of 1.6 meters, and 6 wheels, they also need to complete complex communication, navigation, scientific research, and data analysis and processing functions. This little power is very limited. This is completely different from the scene that everyone imagines of Mars rovers galloping on the surface of Mars. In fact, the speed of the two Mars rovers is calculated in centimeters per second. Their "driving" limit speed is only 5 centimeters per second, and the average The movement speed is only 1 cm/second.

According to its self-protection system, it will stop for 20 seconds every 10 seconds to check the terrain and avoid risks. So the actual effect of driving the Mars rover is: it took 10 seconds to crawl forward about the length of a human hand, then stopped to breathe for 20 seconds, and then continued to crawl forward.

Act 5: The priceless “super car”

The Mars rover must also carry a large number of image camera systems to assist navigation and self-trajectory judgment. After all, there is no one on Mars to help They point the way and must be self-sufficient to complete. Therefore, they all carry a panoramic camera and a navigation camera mounted on the 1.5-meter-high head, and they also need to carry four hazard avoidance cameras to take pictures of the front, rear, left, and right to avoid danger. It can be described as a standard "timid" approach. There is no way. After all, this is an extremely sophisticated car with a cost of 400 million U.S. dollars. After rough calculation, the average value per gram is close to 15,000 yuan, which is comparable to a car made of pure gold (the price of gold is about 300 yuan per gram). The cars are too expensive to make.

Not only that, its small energy still needs to support communication with the earth, but obviously this energy is too weak and far from enough to directly send signals back to the earth. Therefore, their choice is to rely on other "predecessors" to help forward and transmit signals: the United States' Odyssey, Global Surveyor, MAVEN, Reconnaissance Orbiter, etc. have all successively provided them with data transmission services.

After solving core issues such as power, navigation, and communication, we finally got to the most important aspect: scientific research! Although the energy is limited, the two Mars rovers still carry very advanced and highly integrated scientific research instruments. They are basically installed on the mechanical "arms" extending from the front of the Mars rover. This is also a helpless move, because almost the entire back is covered with solar panels, and the bottom is entirely composed of power systems and structural systems.

On the arm, there are instruments such as M?ssbauer spectrometer, alpha particle X-ray spectrometer, and magnetometer that can interpret the chemical composition of rocks and soil in detail, as well as a thermal radiation spectrometer (mounted on the head Department) and microscopy imagers are devices that can observe soil structure images from a distance and at a microscopic close. Of course, in order to assist these instruments in obtaining samples for study, a grinding tool is also needed to crush the rock. When using instruments, the rover needs to stop and concentrate most of the energy on the robotic arm. The robotic arm slowly lifts the front end with the instruments to the place to be studied and puts it down. Only then can the instruments start working.

Act Six: Mars Exploration, Mission Must Be Achieved

According to the plan, Spirit landed in the Gusev Crater, a 170-kilometer-wide super impact crater. The pit may hide the deep secrets of Martian soil; Opportunity landed on Meridiani Planum, where a large amount of crystallized hematite was once found, which means that in ancient times it was most likely a huge ocean/lake on Mars location.

After arriving on Mars, the two little guys lived up to expectations and brought us a massive amount of scientific research results, which greatly supplemented the achievements of the "predecessors" Viking 1/2 and Pathfinder/Sojourner missions. Research results. They further analyzed the composition of the Martian soil. Compared with the earth's soil, which is basically 50% water and air, 5% organic matter, and 45% minerals and metals, the Martian soil only contains 2% water and air, and the remaining 98% of it is minerals and metals. In addition, nickel and zinc elements were discovered for the first time in Martian soil. These two elements are supposed to come from the deep core of Mars. This discovery means that the soil on the surface of Mars may have originated from volcanic eruptions, which is the violent geological activity of Mars hundreds of millions of years ago. product of the period.

Spirit once conducted "deep" research on a Martian rock. It drilled a hole 4.5 centimeters in diameter and 0.5 centimeters deep, almost as big as a baby's hand. It seems that humans can do it easily, but it is really not easy for Spirit: This is the result of two hours of motionless drilling. After analyzing the basic structure of the stone, scientists found that these micro-textures and holes could only have been formed by the involvement of water.

Its "brother" Opportunity studied in detail a large number of basalts similar to those on Earth, covered with multiple layers of different materials. It also visited a clay-rich hill and an ancient lake. At the bottom, water-containing minerals including hematite (a type of rust) have been found, and traces of water flowing through it have even been observed at the bottom of the impact crater, which means that liquid water may still exist underground on Mars today. Opportunity was also lucky enough to encounter a gift from space: it found a meteorite made of iron and nickel, which was also the first time humans found a meteorite on an alien planet.

These all confirm that Mars had a warm and humid environment in ancient times. However, after studying the chemical composition, they concluded that the former oceans and lakes on Mars were not as mild as the water bodies on Earth. Instead, most of the water bodies were highly acidic and were not suitable for the survival of most life on earth. Their research goes far beyond this, but due to space limitations, they cannot be fully expanded upon.

Act 7: We conquer space, not because it is easy, but because it is difficult

Before Spirit and Opportunity set off for Mars, September 11, 2001 , the United States suffered the worst terrorist attack in history, and the two iconic World Trade Center buildings in New York collapsed. This attack caused the death of nearly 3,000 people, and a large number of them were firefighters involved in the rescue. It caused huge losses to the United States. Afterwards, the whole world fell into an atmosphere of mourning, and these two detectors were no exception.

But just like their names, they represent the mood of mankind to become more courageous with each setback. During the cleanup process of the ruins afterwards, scientists used the found metal materials to make a special cable protective cover, which was used to protect the rock crushing tools.

In addition, the places where they landed have become monuments. Among them, the landing site of Spirit is called the "Columbia Monument" to commemorate the disaster of the space shuttle Columbia disintegrating during its return on February 1, 2003; correspondingly, the landing site of Opportunity is called the "Challenger Monument". To commemorate the disaster of the space shuttle Challenger that disintegrated during takeoff on January 28, 1986. In these two space disasters recorded in the annals of human history, seven astronauts died each, making them the most in history.

As President Kennedy famously said: "We chose to land on the moon, not because it was easy, but because it was difficult." The two Mars rovers also shoulder the great mission of mankind.

Act 8: Veterans survive and create miracles

The original planned working time of these two Mars rovers is about 90 days. Scientists believe that after 90 days, the sand in the Martian air will Dust will cover the solar panels, causing the energy to be too low to continue working. But unexpectedly, the violent sandstorms and windy weather on Mars helped. The wind blew away the dust covering the surface of the solar panels, allowing them to be re-exposed to sunlight and reborn. Although the two brothers almost failed their mission in the huge dust storm on Mars in 2007, 99% of the sunlight was blocked by dust for several months, but they finally survived in the harsh environment through hibernation, with wind speeds more than 10 times faster than those on Earth. Come down and win a new life.

Under this circumstance, Spirit continued to work until March 22, 2011, when the mission was declared over. It had already experienced wheel failure and could not rotate, and had sunk into soft soil in 2009. It couldn't move at all, but it still kept working in that pit for two years until it lost contact, and that became its final graveyard.

The Opportunity rover was in much better shape. It once got stuck in a patch of gravel sand, but later relied on various simulations by its two "cousins" on Earth to finally escape in a month and a half. , that small area was renamed "Hell Dunes". From then on it was more careful and worked until mid-2018.

But Opportunity in the later period is also slowly getting older. The computer on board will continue to restart every day, and the data storage will be automatically cleared after working for a period of time. It is like an old man suffering from "dementia" in his twilight years. " and "Amnesia" make people feel regretful and helpless.

Although Spirit and Opportunity move extremely slowly, their long service life makes them the best Mars rovers. Spirit worked for a total of 2,269 days, and Opportunity worked for more than 5,000 days. The Opportunity rover moved at an average speed of 1 cm/second and set a record for the farthest distance traveled in space. It has traveled more than 45 kilometers on the surface of Mars, already surpassing the Lunokhod 2 launched by the former Soviet Union in 1973. ) set a record of 39 kilometers on the lunar surface. Opportunity is like the tortoise in the tortoise and the hare race. Although it was slow, it persisted until the final victory.

However, the tragedy is that in 2018, Mars experienced a huge dust storm that swept the world, and Opportunity fell into sleep again due to energy problems. After the sandstorm subsided at the end of the year, NASA tried more than 800 times to contact it but failed to wake it up, and finally had to give up. We have now lost these two rovers forever.

Act 9: A magnificent finale, but also a beginning

Although the missions of Spirit and Opportunity have ended, their magnificent finales have not. Their great success once again set off a climax of human Mars exploration. After that, a series of detectors arrived on Mars and worked for a long time.

In June 2003, the European Mars Express orbiter and the Beagle 2 lander arrived, and the orbiters are still working today;

In March 2006, the US Mars Reconnaissance Orbiter Arrived and is still working today;

In May 2008, the US Phoenix lander arrived;

In August 2012, the US Curiosity Mars rover arrived and is still working today;

In September 2014, the US MAVEN atmospheric expert orbiter arrived and is still working today;

In September 2014, India's Mangalyan orbiter arrived and is still working today;

In October 2016, the European ExoMars orbiter and Schiaparelli lander arrived, and the orbiters are still working today;

In November 2018, the American InSight landed The "nuclear-powered" Curiosity Mars rover arrived and is still working today;

The "nuclear-powered" Curiosity Mars rover is almost five times the size of Spirit/Opportunity, and its capabilities have been fully upgraded in all aspects (Source: NASA)

In the next 2020, China, the United States, Russia/European Union, etc. will all have a new round of Mars exploration missions to Mars, and Mars will usher in its busiest period. There is no doubt that their research results will greatly surpass Spirit and Opportunity.

Following the exploration of Mars, humans in the future will completely conquer Mars

In January 2004, then-President Bush of the United States proposed a "new space plan": to return to Mars before 2020 He will establish a permanent base on the moon and send astronauts to Mars, but he did not announce a specific landing date.

In 2017, Trump signed the "Space Policy Directive No. 1" and announced ambitious plans including returning to the moon, landing on Mars and in-depth exploration of the solar system. To this end, the United States reorganized the National Space Council, with Vice President Pence as chairman. Trump has also repeatedly stated on Twitter that NASA should directly launch manned exploration of Mars and announce relevant plans in the next few months.

In the same year, at the 58th International Astronautical Federation Congress in the southern Indian city of Hyderabad, former NASA Administrator Michael Griffin claimed to be preparing to send humans to Mars in 2037. But during NASA’s fiscal year 2020 budget request hearing, current NASA administrator Jim Bridenstine confirmed that the United States plans to send astronauts to Mars in 2033 and survive on Mars for 2 years.

NASA is not the only one who wants to be the first in exploring Mars. Major aerospace companies such as SpaceX and Boeing are also competing privately. Dennis Muilenburg, the head of Boeing, made it very clear in an interview: "The first person to set foot on Mars will fly there on a Boeing airplane."

Dennis Muilenburg's The statement was ridiculed by rival SpaceX's Elon Musk. He claimed that the comment that "Boeing will beat SpaceX in the race to Mars" sounds like Boeing is telling itself, and it is self-deceiving.

Of course, for Elon Musk, his dream is not just to send humans to Mars, he even wants to transform the atmosphere of Mars and transform Mars into a planet suitable for human habitation.

Musk initially stated during a TV show that he wanted to heat Mars with nuclear bombs. And he wasn't kidding, detailing the plan on Twitter in 2019. Musk also threatened to build 1,000 Starships for travel to Mars.

Although Musk is full of expectations and confidence in the Mars plan, he has admitted that he may not be able to realize the Mars plan himself because the development of technology is somewhat unsatisfactory. Musk has repeatedly called for accelerating technology research and development. He even claimed that if the technology matures, there is a 70% chance that he will land on Mars himself. Judging from the current situation, Musk's dream is very likely to come true if it is not just words.

What is certain is that when NASA targets Mars, the major private aerospace companies in the United States will not limit their goals to the moon alone. The race to Mars has become inevitable.

As early as 2003, in order to make preliminary preparations for a manned mission to Mars, scientists from NASA, the European Space Agency and the French Space Agency were conducting various "human adaptation to space" experiments in Antarctica. This is because a round trip to Mars would take up to 2 years. Prolonged isolation, loneliness and helplessness may break through astronauts' psychological defenses and lead to insanity.

To this end, NASA has specially built the HI-SEAS Mars simulation base. Because experts believe the only way to truly understand the psychological challenges astronauts may encounter is to expose them to extreme environments similar to those on Mars. Those who have experienced the simulation test have deeply experienced the isolation and loneliness of astronauts.

In NASA's plan, there is no plan to fly directly from the Earth to Mars, but to use a lunar base or space station as a relay station. Of course, both are still in preparation. Americans have not yet completed their goal of returning to the moon, so a lunar base can only be a dream for the future. But the idea of ??using a lunar base as a relay station is popular because the water ice stored in the lunar poles can fully produce future rocket fuel.

NASA proposed in 2017 that it plans to establish a permanent base in lunar orbit, also known as the Deep Space Gateway. It will serve as a training ground and technology experiment site for future space exploration, aiming to prepare for human landings on Mars or other planets. The base is like an airport where spacecraft heading to the lunar surface or Mars can refuel, replace parts or replenish supplies.

A powerful launch vehicle is the basis for humans to go to the moon and even Mars. The launch vehicle is the basis for humans to escape the gravity of the earth and go to Mars. It is also the most important basis for the entire human spaceflight. Its capabilities often determine an aerospace enterprise. and the upper limit of a country’s space exploration capabilities.

In 2015, the Space Launch System SLS designed by NASA passed expert review, which meant that the largest and most powerful rocket in human history finally took a critical step.

The SLS system is a heavy-lift launch vehicle derived from the U.S. Space Shuttle. It is part of NASA's "Deep Space Exploration Program" and will shoulder manned missions to Mars and the Moon in the future.

The SLS rocket is similar to the Ares IV rocket, but its total thrust ratio will exceed that of the previous largest Saturn V, making it the most powerful launch vehicle in the United States.

In 2017, NASA announced a new generation of Mars rover "Mars 2020", which is now the Perseverance Mars Exploration Rover. In the near future, this rover with 23 “eyes” will carry out panoramic observation missions on Mars. These 23 cameras include 7 science cameras, 7 auxiliary cameras for landing, and 9 engineering cameras that can help the rover avoid obstacles on Mars.

From a strategic sense, the United States wants to expand and firmly occupy the leadership position in space exploration by exploring Mars. At present, the United States is no longer alone in the field of space exploration. Various countries, including China, have risen and begun to challenge the leadership of the United States.

If technology is the boundary of our human capabilities, then exploring space and understanding the universe is the boundary of our thinking.

Recently, too many keywords focus on the so-called Metaverse, but I was touched by a sentence from BGI Yin Ye. In the face of people’s enthusiasm for the Metaverse, he only said one sentence, "I care more True universe".

Because no matter how fancy the so-called metaverse is, it is all created based on the real world. Whether you make Einstein into an AI to talk to you, or you copy yourself into 8 clones, You need enough knowledge and skills to achieve it.

These algorithms, technology, and mathematical knowledge are all learned by you in the real physical and biological world. The boundary of the metaverse is much smaller than the boundary of the real universe...

The three major origin issues of mankind will be our eternal puzzles to explore: the origin of the universe, the origin of life, and the origin of consciousness.

Exploring the universe and understanding ourselves are actually important directions for us to explore this great subject.