[취재파일] Window to the future… Mars Exploration Rover Perseverance

At around 5:58 am on February 19th in our time, Mars exploration rover personals landed in the crater (Jezero Crater) as an example. It has been seven months since it was launched on July 30, 2020 from Cape Canaveral Air Force Base in eastern Florida, USA.

When the cruise stage fell 10 minutes before entering Mars’ atmosphere, the flying saucer-shaped Perservation capsule attempted to enter Mars’ atmosphere, and the parachute unfolded and succeeded in deceleration. The descent stage was suspended from a sky crane and landed lightly on Mars. After entering the atmosphere, the process of separation of the heat shield-deployment of the parachute-separation of the parachute from the backshell-deployment of the sky crane-touch down-the separation of the sky crane proceeded steadily like a science fiction movie.

Just before launching from Earth and entering Mars, the Perservation Capsule is a cruise stage that helps movement, a backshell that covers the rover, a descent stage that aids in descent just before landing, and a rover (as shown in the picture above). rover) and heat shield.

Rover Perservance’s landing on Mars, which runs like a car on the surface of Mars, is the fifth time after Sojourner in 1997, Spirit and Opportunity in 2004, and Curiosity in 2012. Unlike the Sojourner and Spirit landing on airbags, Curiosity and Perseverance landed on the Skycrane.

Although the design is similar to Curiosity, which landed on Mars in 2012 and has been conducting exploration missions for 9 years in the Gale Crater, it has upgraded navigation and exploration equipment, equipped with a drone helicopter, and entered Mars’ atmosphere. It contains 8 years of technological advancement, including the installation of a MOXIE system that creates oxygen.

Mars, which is the fourth planet after Earth in the solar system, is half the size of the Earth, but it has an Earth-like atmosphere and traces of water flow, such as a large delta, and it is estimated that life existed 3 billion years ago. Perseverance is a project that will enable another leap in space exploration technology in that it is tasked with testing the devices that allow humans to live, as well as finding traces of life on Mars.

Mars Rover Persitivity is also an exhibition hall where you can preview the science and technology that will be commercialized in everyday life in that space exploration uses all the cutting-edge technologies developed by mankind. With a weight of 1025 kg, a length of 3 m, a width of 2.7 m, and a height of 2.2 m, let’s see what technology is hidden in the Mars Exploration Rover Perservation, which is similar in size to a passenger car.

● Nuclear-powered car rover going with plutonium

On Mars, where the air density is one-hundredth of the Earth and 96% carbon dioxide, the fuel that drives the six-wheeled rover performance on Mars is 4.8 kg of plutonium 238 mounted on the rover.

A 66cm wide and 64cm long nuclear battery (RTG) installed at the rear of the rover converts the heat emitted by natural attenuation of radioactive isotopes into electrical energy to generate 110w of electricity. It is a generator that uses the principle that thermoelectric power is generated in a circuit when a temperature difference is given to both metals or semiconductors.

The half-life of plutonium 238 is 87.9 years, and the energy released by plutonium is halved every 87.9 years. The lifetime of the RTG installed in the facility is 14 years, reducing the voltage generated every year by several percent, NASA said. After generating electricity, the remaining electricity is charged to the lithium-ion battery and used when necessary.

Nuclear cells have been used as power sources for spacecraft for decades, starting with the Apollo spacecraft. Plutonium is made in ceramic form to minimize explosion or radiation leakage in case of emergency. Even if the spacecraft explodes, the amount of radiation exposure is 210 millirems, which is less than 310 millirems of radiation that Americans are exposed to a year in nature, NASA says.

● Self-driving system and helicopter with three times higher operating speed

After entering the Mars atmosphere at 19,000 km/h, 20 times the cruise speed of an airliner, Perseverance landed while observing the Mars surface with a radar and seven cameras. The navigation system was upgraded to find the landing location on its own by scanning the surface, comparing it to the original landing point, and adjusting when the parachute unfolds.

The brain of Perseverance is a computer with a processing speed of 200 megahertz, 2 gigabytes of flash memory, and 13 processors that can withstand radiation. There is one more spare computer to perform the backup function in case of emergency. Optical sensors and machine learning algorithms self-check the rover’s condition and find its way.

Rover’s software is written and updated on Earth. The length of the wire that connects complex mechanical devices to each other reaches 5.8 km. By applying the autonomous driving system accumulated over the past eight years since Curio City landed on Mars in 2012, it can travel at 6.6 km per hour, three times faster than Curio City.

There are two microphones that can be heard and 23 HD-class high-definition cameras installed in the facility. Two mast cameras installed in the front can see objects in three dimensions and measure distances. With high-performance cameras, drilling rigs, and long arms equipped with observation equipment, you can see things closer and take selfies.

Compared to Curiosity, the diameter of the wheel was increased from 50.8cm to 52.6cm, and the width was reduced from 43cm to 33.6cm. By changing the shape of the groove of the wheel, increasing the strength of the aluminum wheel to reduce wear, and increasing the diameter of the wheel, it is possible to pass through obstacles with a height of 40 cm and climb a path with a slope of 30 degrees.

Mars Exploration Rover Perservation carried the drone helicopter Ingenuity in the bottom. The helicopter Ingenuity, which weighs 1.8 kg and has a width of 1.2 meters, will start maneuvering within a month and will test whether it can fly on Mars, which has a gravity of one-third of the Earth but only one-hundred of the Earth’s air density. .

When 6 lithium-ion batteries are charged through the solar panel, the attached camera and sensor are used to rotate the propeller about 3,000 times per minute, which is about 5 times the Earth’s, for autonomous flight. The goal is to gradually increase the flight altitude and increase the flight time to fly up to 90 seconds. If the helicopter flight is successful, it is expected that another breakthrough in the exploration of Mars will be possible.

● Advanced three-dimensional exploration equipment

The facility was equipped with 23 cameras, 2 microphones, and 7 exploration equipment. It is also possible to analyze the components of minerals by shooting images or sound returning by shooting light rays without drilling soil or rocks with a spectrometer, chromatograph, radar, and X-ray equipment.

The RIMFAX radar can detect the presence of water up to 10 meters underground without digging. EDA measures the climate on Mars, including dust, temperature and humidity, and wind.

If necessary, samples are collected and analyzed, and then stored in 47 containers and stored in a specific place. This sterile, clean, fountain pen-sized container will be launched into an orbiting satellite by an exploration rover, which will be launched in 2026, and the orbiting satellite is planning to take the samples and bring them to Earth intact.

● Oxygen Generator Visual (MOXIE)

The most notable device in Percivility Rover is the Mars Oxygen In situ Resource Utilization Experiment (MOXIE), which uses Mars’ atmosphere to create liquid oxygen. Until now, at the space station, water (H2O) taken from the earth was electrolyzed to make oxygen (O) and hydrogen (H). Water is so heavy that it is difficult to transport to Mars, so it was decided to create oxygen into the atmosphere on Mars.

Moxy compresses carbon dioxide (CO2), which accounts for 96% of Mars, at high temperatures to produce oxygen (O2) and carbon monoxide (CO) through Solid Oxide Eletrolysis. Moxie is a prototype that produces 20 grams of oxygen per hour, and if the test is successful, he will build a device that produces 2 kg of liquid oxygen per hour and send it to Mars. The oxygen produced in this way is also used as fuel for rockets that people going to Mars breathe and return to Earth.

A space suit and helmet were also mounted on the Perservance to test whether it can withstand Mars’ atmosphere and rays. If oxygen is made into Mars’ atmosphere and tests on equipment such as spacesuits and helmets are successfully carried out, it becomes possible to provide space for humans to live on Mars. If traces of life are found here, the hypothesis that there are other places other than Earth live in outer space is confirmed as a groundbreaking discovery.

With the development of human science and technology, travel time in outer space will be shortened, and new methods of making water and oxygen that can survive in a barren environment will be completed, and it will be possible to move to another planet. The world’s attention is focusing on whether Perseverance will penetrate the first gateway for humans to advance into outer space outside the Earth, and whether it will be possible to identify other life forms in space other than humans.