Cold Welding Based Space Debris Removal System

Space Debris is a major problem posing a great threat to all the future space travels as well as to all the satellites which are orbiting around the earth. According to a definition by the Inter-Agency Debris Coordination Committee (IADC) “space debris are all man-made objects including fragments and elements thereof, in Earth orbit or re-entering the atmosphere, that are non-functional” [1]. According to J. C. Liou, even if we stop all the space launches the amount of space debris will remain constant up to 50 years but will increase later due to collisions among them [3], [4]. Till December 16, 2019 a total of 20047 objects are on orbit out of which 5370 objects are payloads and 14677 are debris, this means about 73% of the objects in orbit constitutes debris. [2] The rate at which the debris is generated is much greater than the rate at which this debris deaccelerates, leaves the earth orbit and re-enters the earth atmosphere. We can protect the future space missions from huge debris particles that are traceable but the small debris elements pose a major threat. In this paper we propose a technique to remove the small debris particles from Lower earth orbits based on cold welding. Cold welding is the process in which two similar metals stick to each other when there is a metal to metal contact in space. This happens because on the ground these metals have layers of oxides thus, two pure metals never come in contact but in space, due to wear and tear, this layer of oxides get removed irreversibly and as a result, pure metals come in contact and the adhesive forces cause the metals to join. The debris is orbiting around the earth at a speed of 17500 mph [10]. For our system we use a composite material made up of a combination of elements that usually orbit the earth. Since, in relative frames they are stationary by increasing the velocity with controlled amount we can control the impact during contact. We will propel this composite material with the same speed around the earth as the debris, so that in their relative frames it appears stationary. By bringing the debris particles into contact with the composite material, cold welding will take place between them and then, we will send the system to international space station where the captured debris particles are removed from the composite material. By repeating this process, we can remove most of the small debris particles of size less than 10cm which are orbiting around the earth in lower earth orbit.