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What Is the Power Source Used by China’s Tianwen-1 and USA Mars Rover?

China’s Tianwen-1 Rover successfully landed on Mars on May 15, 2021, using solar panels ,namely solar battery.

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Tianwen No.1 picture from Baidu.com

Tianwen No.1 is the China Aerospace Science and Technology Corporation responsible for the implementation of China’s first autonomous Mars exploration mission.

Tianwen-1 was launched into space on July 23, 2020 and successfully entered the scheduled orbit.

On February 10, 2021, the Tianwen-1 probe successfully entered the orbit of Mars and reached the vicinity of Mars to capture Mars.

On April 24, the name of China’s first Mars rover was confirmed as “Zhu Rong”.

On May 15, 2021, the Zhurong rover and its landing complex carried by the Tianwen-1 Mars Rover successfully landed on Mars. , China’s first Mars exploration mission landing on Mars was a complete success. Zhu Rong will carry out inspections and other work in the future, scientific exploration of Mars surface morphology, soil properties, material composition, water ice, atmosphere, ionosphere, magnetic field, etc., to realize China’s technological leap in the field of deep space exploration.

The Tianwen 1 rover is powered by solar panels, it is solar battery. The rover is 1.85 meters high, weighs about 240 kilograms, and is equipped with 4 “butterfly wings”-solar panels.

Because China’s Tianwen No. 1 is powered by solar battery, there is often a lot of sand and dust on the surface of Mars, which will cover the surface of the solar cells, reducing power generation efficiency and even loss of power generation capacity. For the rover, the loss of energy supply is undoubtedly fatal. Therefore, the orbiter detects the pre-selected landing area in advance, learns about sand and dust storms and other trends, and avoids bad weather.

China’s exploration of Mars has just started. The reason why Tianwen-1 is not equipped with nuclear batteries is that China is technically immature. The nuclear battery was used in the previous lunar exploration. It was jointly developed with Russia and the power is still very small. Compared with the nuclear battery on the Curiosity Rover, there is still a big gap. Moreover, plutonium-238 is a radioactive material, which is relatively expensive. Once the launch fails, the launch vehicle will explode and a large number of radioactive materials will be released into the atmosphere, which will inevitably pollute the country. In addition, Tianwen-1 is China’s first Mars rover. It is technically immature, with a certain experimental nature, and its life span cannot be too long. Although it is crossing the river by touching the United States, whether it is for safety reasons or from an economic point of view, the first use of solar energy is the best choice.

#1 – What Battery Does the Us Mars Rover Use?

It has been 54 years since November 1946 in the United States. The United States has launched nearly 20 Mars probes to Mars.

Prior to 2011, including the “Opportunity” Mars rover that was launched on July 7, 2003 and safely landed on the surface of Mars on January 25, 2004. And on January 4, 2004, the “Valence” that landed on the Gusev crater in the southern hemisphere of Mars used solar battery to power itself.

As of January 25, 2018, the “Opportunity” Mars rover has been roaming Mars for more than 14 years and has achieved great results.

“Opportunity” uses solar panels (solar battery)to provide power. The solar panel array can generate about 140 watts of electricity on each Martian day, allowing rechargeable lithium-ion battery to store power and use it for nearly 4 hours at night. The computer on the body of Opportunity uses a 20MHZ RAD6000 central processing unit, 128MB of DRAM, 3MB of EEPROM and 256MB of flash memory. The operating temperature of its car body ranges from −40 °C to 40 °C. The radioisotope thermal motor on the car, which can be supported by electric heaters when necessary, also provides basic temperature control. A gold film and a layer of silica aerogel are used for heat insulation,

Due to the frequent occurrence of sandstorms and dusty winds on Mars, the efficiency of solar panels is reduced. In addition, because the distance between the sun and Mars is too far, the average distance of Mars orbiting the sun is 2.28 million kilometers (141.67 miles), which is 1.524 astronomical units (slightly greater than 1.5 times the distance between the sun and the earth). The solar panels on the Mars rover not only have to face the sun, but also require the sun to be irradiated almost vertically to collect energy effectively, so there is insufficient energy collection.

In order to change this situation, the United States has used nuclear battery instead of solar battery to provide power support for the probe since the launch of the “Curiosity“ Mars probe in 2011.

The “Curiosity” Mars rover is a Mars rover developed by NASA for a mission to explore Mars. It was launched in November 2011 and successfully landed on the surface of Mars in August 2012. It is the seventh Mars landing probe in the United States, the fourth Mars rover, and the world’s first nuclear-powered Mars rover.

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“Curiosity” Mars rover picture from Baidu.com

On July 30, 2020, the US “Perseverance” rover took off. The Perseverance probe landed safely on February 19, 2021, Eastern Time in a spectacular “sky crane” method. On March 4, “Perseverance” completed its first mission to Mars, leaving an exclusive mark. The Perseverance was also equipped with the “Witty” helicopter. On April 19, Eastern Time, the “Wit” helicopter carried by the “Perseverance” rover took off on the surface of Mars.

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“Perseverance” rover & “Wit” helicopter picture from Baidu.com

The core of the Perseverance is a small “nuclear battery” the size of a beer barrel, called a radioisotope thermoelectric generator (RTG). Unlike nuclear reactors that generate electricity on Earth, RTGs can generate electricity without initiating or maintaining a fission reaction. They don’t even have any moving parts. Instead, they passively collect the natural heat generated by the decay of 238238 and convert it into electrical energy. They can reliably provide energy and heat for spacecraft.

#2 – What Is a Nuclear Battery?

Nuclear battery is not a black technology. They existed decades ago, and nuclear batteries have been used in pacemakers. Nuclear batteries in the aerospace field generally use isotope temperature differences to generate electricity. Generally, the preferred nuclear material is the radionuclide plutonium 238, which has a half-life of 86.4 years. Radionuclides can decay spontaneously, and the energy produced when a certain mass of radioactive material decays is enough for a Mars rover to use. Plutonium 238 is widely used in various spacecraft by the United States, which can not only heat the detectors, but also provide electricity.

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The picture below shows the plutonium 238 that is emitting heat picture from Baidu.com

Nuclear power battery is still the best energy source for exploring Mars in the future. Mars is far away from the sun, and the light intensity is only 40% of that on the earth. In the absence of sunlight or insufficient sunlight, nuclear batteries can not only provide auxiliary power supply, but also can be used as an isotope heat source to keep the rover at night, which can greatly improve The working efficiency and longevity of the rover.

Powering Curiosity on Mars—And Beyond ,details please refer the below link,https://www.powermag.com/powering-curiosity-on-marsand-beyond/

A nuclear Power Plant Arrives on Mars, Rover Attached, details please refer the below link,https://www.nei.org/news/2021/a-nuclear-power-plant-arrives-on-mars

Carl Zhang

Carl Zhang

I am a senior sales with 15 years in the battery industry and a bachelor's degree in economics.
I will be sharing some of my expertise on batteries and my insights into the battery industry in my blog, which should help you with your purchases in China.

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