Research On The Method Of Rapid Expansion Of Asteroids

With the deepening of deep space exploration,aerospace powers such as the United States and Japan have carried out many researches on asteroids,and asteroid exploration activities have increasingly become hotspots at the forefront.In asteroid exploration,contact detection is the most direct and effective means for humans to perceive asteroids.In order to fully understand the asteroids,the acquisition and return of deeper samples is required.China is actively carrying out research on asteroid exploration and sampling.The preferred target is asteroid 2016HO3.Because the asteroid’s gravity is very weak,the surface environment is uncertain and it has extremely demanding requirements for sampling.Ultrasonic drilling has a small reaction force and can work effectively on an asteroid.However,due to the limitation of power consumption,the amount of rock sample is small,and the sample is mostly powder,which is not suitable for collection.In order to obtain more samples,this paper proposes a new method of rock crushing-ultrasonic drilling plus supercritical fluid expansion rock breaking method,first using ultrasonic drill to drill a hole 7cm deep on the rock,and then expanding the rock The device is inserted into the drilled rock hole for expansion of the rock,which can quickly break the rock under urgent resources to obtain a larger sample.Because ultrasonic drilling is more researched in China,the technology is more mature,and the method of supercritical fluid expansion and rock fragmentation has not been studied.Therefore,this paper mainly studies the method of supercritical fluid expansion and fragmentation.This method utilizes the principle that the supercritical fluid has the infinite temperature and pressure to crush the rock,which can break the rock of different hardness.In this paper,supercritical water is selected as the expansion medium,and the thermodynamic characteristics of supercritical water are studied.The quantitative relationship between temperature,pressure and volume of supercritical water is obtained.The heating method in the method of expanded rock is studied in this paper.The drilling tool is rapidly heated during the rotation process,and the induction heating method with high heating efficiency and easy heating temperature control is selected.In this paper,an expansion rock crusher is designed,and the overall structural design and parameter calculation are carried out to ensure heating.The safety of the water storage pressure vessel and the non-leakage of the expansion cylinder during rock crushing;this paper uses the finite element software to simulate the thermo-mechanical coupling of the water storage pressure vessel,and obtains thestress value of the water storage pressure vessel under the wall thickness.To ensure the safety of the container during heating;this paper uses the finite element software to simulate the superplastic deformation of the expansion tube,and achieves the matching design of the strength.Through the simulation verification in the simulation stage,it is possible to realize reliable rock fragmentation under human cognitive rock hardness and have the ability to acquire samples.