Deep-Sea Thrusters: The Power Core for Exploring the Underwater World​

At the Mariana Trench, which is 10,000 meters deep, the water pressure is equivalent to 1,000 atmospheres—strong enough to crush steel. Yet, deep-sea probes can move freely here, and the core contributor behind this is the deep-sea thruster. Like the "limbs" of deep-sea equipment, it provides precise power for submersibles and underwater robots, serving as a key technological support for humanity's exploration of the ocean's unknowns.

The core mission of deep-sea thrusters is to provide stable thrust in extreme environments. Their working principle is based on Newton's Third Law: the internal power unit of the thruster drives fluid (seawater) to spray out at high speed, generating reverse thrust to propel the equipment forward.

Unlike land or aviation propulsion systems, deep-sea thrusters must overcome three major technical challenges. First is high-pressure resistance: they need to withstand the enormous pressure of the deep sea at the kilometer level. Titanium alloys, special ceramics, and other pressure-resistant materials are usually used, and the sealing structure adopts a multi-layer redundant design to prevent seawater from seeping into the motor. Second is corrosion resistance: the strong corrosiveness of seawater can quickly erode metal components. Therefore, the surface of the thruster is coated with a special coating, and corrosion-resistant alloys are used for key components. Third is low noise and high efficiency: deep-sea exploration requires concealment while saving energy. Hence, thrusters mostly adopt optimized propeller designs and brushless motor drives to improve thrust efficiency while reducing noise.

Based on power sources, deep-sea thrusters are mainly divided into three types. Electric thrusters are the most widely used type currently; they are powered by batteries to drive motors, featuring a simple structure and low noise, making them suitable for scientific research submersibles. Hydraulic thrusters are driven by high-pressure hydraulic oil, offering large thrust and strong impact resistance, and are often used in heavy-duty operation equipment such as deep-sea mining robots. Jet thrusters spray seawater at high speed through high-pressure water pumps, without the need for propellers. They are suitable for operations in areas with complex terrain or obstacles to avoid entanglement risks.

In practical applications, the "precision control" of deep-sea thrusters is particularly crucial. Modern deep-sea equipment is usually equipped with a power system composed of multiple thrusters. Through computer control of the thrust magnitude and direction of each thruster, complex movements such as advancing, retreating, turning, and hovering are achieved. For example, China's "Striver" (Fendouzhe) full-ocean-depth manned submersible is equipped with 6 main thrusters and 4 fine-tuning thrusters, enabling it to accurately position itself at the 10,000-meter seabed and complete tasks such as sample collection and shooting.

With the in-depth development of ocean exploration, deep-sea thrusters are moving toward the direction of miniaturization, high power, and intelligence. Researchers optimize fluid dynamics designs and use new motor materials to reduce volume while increasing thrust density. Combined with artificial intelligence technology, thrusters can automatically adjust their working modes according to the marine environment to adapt to different sea conditions. In the future, more advanced deep-sea thrusters will help humanity explore deeper underwater secrets and provide strong power support for fields such as deep-sea resource development and marine environmental protection.