Language
Country/Area
No result found
Unmanned and Controlled Recovery: How Does a Spacecraft Choose the Entry Method?
With the advancement of space technology, the controlled recovery of unmanned spacecraft has become a hot topic, and the choice of entry method is crucial to the success of its mission.
Atmospheric entry is the process by which an object enters the atmosphere of a planet, large planet or natural satellite from outer space. This process can be uncontrolled, such as the entry of an asteroid or space debris, or a controlled recovery of a spacecraft. This is how the unmanned recovery system performs its mission, which has a profound impact on the future of space exploration and technology.
Controlled atmospheric entry, descent and landing (EDL) is an integral part of space exploration, a term that applies not only to Earth but to other planets as well.
During the entry process, the object will face atmospheric resistance and heat caused by air compression. These forces can cause material loss or even complete disintegration. Due to the extremely high speed upon entry, even small objects can collapse from the intense heat and pressure. A common challenge for unmanned spacecraft is how to control these forces within acceptable limits to ensure safe recovery of equipment and cargo.
In order to differentiate their entry methods, unmanned spacecraft usually rely on two basic design concepts: using lift to decelerate and land, and jump re-entry and other technologies.
From a historical perspective, entry designs for unmanned spacecraft have evolved significantly. Early ballistic missiles were technically limited in design, and only with the development of modern heat shield technology did entry into design and re-entry flight become possible. For example, US research in the 1950s found that blunt shapes chemically and physically provided the best thermal protection during re-entry.
Enter the shape design of the device
When designing into a device, there are several basic geometries. First is the spherical part, which is the simplest symmetrical shape and has the advantage of being easy to analyze.
The heat flow and aerodynamic models of the spherical structure have been accurately determined, providing an important reference for the design of unmanned spacecraft.
The second is the spherical cone shape, that is, a blunt cone shape attached to the spherical front end. This design usually has more advantages in stability than a separate spherical component. Furthermore, it is a double cone type, which provides a higher lift-to-drag ratio, which is especially important for space missions transporting personnel.
Thermal management during entry
During entry, the unmanned device will experience extremely high levels of heating. This heating mainly comes from two sources: convection of hot air currents and radiation from chemical reactions. As the speed increases, the effect of radiant heat becomes more and more significant, especially in the early stages of entry into the atmosphere.
Scientists use different models to understand the origin and behavior of this heat, which is critical to designing appropriate thermal protection materials.
Latest developments in controlled entry technology
As technology continues to advance, new controlled access technologies are emerging. For example, using fluid dynamics, computational fluid dynamics and advanced materials to reduce thermal loads on entry. These technologies not only increase mission success rates but also reduce the risk of failure.
Future unmanned spacecraft will be able to complete their atmospheric entry and landing missions more efficiently and safely.
