The secret of "Tianwen No. 1" is amazing

The "Tianwen-1" Mars rover is scheduled to land on Mars and carry out patrol exploration from May to June 2021. Facing the "extremely hot" and "extremely cold" mission conditions, a "nano-aerogel" "The new thermal insulation material will escort the Mars probe. What is the magic of nano aerogel? How to escort "Tianwen No. 1"? What impact will it have on our lives?

Airgel ultra light performance display

What is the magic nano aerogel?

In the "Tianwen-1" Mars probe, a number of "black technologies" independently developed by my country are used, one of which is the thermal control material used on the Mars rover - nano aerogel. As a new type of thermal insulation material, it will be used to deal with two harsh environments of "extremely hot" and "extremely cold". At the same time, the ultra-light nature of the nano-aerogel greatly reduces the burden on the rover, allowing it to run faster and farther.

Zhang Hao, deputy director of the 306 Institute of the Third Academy of China Aerospace Science and Industry Corporation, introduced that nanogel is a material that is not well known to the public. It is a three-dimensional network composed of nano-scale solid skeletons. The network structure contains rich The porosity can be as high as 99.8%. Because of its nanoscale skeleton structure, visible light can pass through the middle, and Rayleigh scattering occurs, making the most common silica aerogel look like frozen blue smoke to the naked eye, which is similar to the sky. The principle of rendering blue is the same, so it also has a nice nickname called "blue smoke".

When we use the aerogel material to block heat, its slender skeleton makes it very difficult to conduct heat, which is equivalent to letting the heat walk a labyrinth on a three-dimensional network along the small intestine; and a large number of nanopores are like a separate The room is closed, so that the gas molecules can neither flow nor contact each other, and the convective heat transfer can be eliminated.

Li Wenjing, director of the Fifth Technology Department of the 306 Institute of the Third Academy of Aerospace Science and Industry of China, said that aerogels have two notable features. One is that it is very light in weight, and a large piece of aerogel can be placed on softer flowers and feathers. This is because the porosity of the aerogel is particularly high, reaching more than 99.8%, and it is basically filled with air, which gives the aerogel a particularly lightweight performance. The second is that the wall surface area is particularly large. When 10 grams of aerogel material is completely spread out, the surface it has can cover a standard football field.

How to escort "Tianwen No. 1"?

Zhang Hao introduced that a total of two aerogel materials were used on "Tianwen-1", which were used to deal with "extreme heat" and "extreme cold" respectively.

The "extremely hot" test appeared in the Mars landing stage. The heat generated by the landing engine made the surrounding temperature exceed 1000°C. The thermal insulation component can block the high temperature. Only about 10mm of material can keep the temperature behind it at an acceptable level during the entire landing process. range. Like the fire suits that firefighters wear.

The "extremely cold" test appeared in the Mars tour stage. By laying a large-area aerogel sheet on the surface of the rover, it can ensure that the rover works normally in an environment of minus 130 °C. Like the winter clothing worn by mountaineers. In order to reduce the burden on the Mars rover, let it "run" faster and "run" farther. The ultra-low density aerogel is used here. Its own density is only 15mg/cm³. Under the same volume, its weight is only 1/500 of steel, 1/180 of aluminum and 1/60 of water.

The choice of this material is due to its inherent advantages in density, temperature resistance and thermal insulation properties, and second, it can achieve performance differentiation through the regulation of microstructure, and further enhance the performance advantages of a certain aspect. Play, that is, make the longboard longer.

"The atmosphere of Mars is composed of carbon dioxide, and it is necessary to use a thermal insulation material that can block gas conduction. We put an 'aerogel' coat on the Mars rover, so that it can resist the extremely low temperature of minus 130 ℃." Li Wenjing Introduced.

Will there be applications on space station missions this year?

Zhang Hao introduced that during the construction and operation of the space station, the aerogel material will perform transportation tasks with the Long March 5 series rockets and the Tianzhou-2 cargo spacecraft. Aerogel materials have been widely used in the aerospace field, involving more than 30 types of aerospace equipment, which have spread to various types of aircraft in low altitude, high altitude, near space and deep space.

Airgel insulation performance display

How to "fly into" ordinary people's homes?

With the country's proposal for "carbon peaking and carbon neutrality", the requirements for energy conservation and environmental protection will become higher and higher, and the thermal insulation properties of aerogels can play a greater role. For example, the high-temperature pipelines used in large chemical plants can reach more than 3,000 kilometers. If better insulation materials such as aerogel are laid, the energy consumption of the plant will be greatly reduced. It has broad application prospects in the fields of industrial insulation, new energy vehicles, ships, elevator fire prevention, cold chain refrigeration, building energy conservation, and household appliances.