Mars Rover Landing Airbag Impact Attenuation System

Inflatable airbag system can absorb the energy by the fiber’s elasticity and compressing the air inside,so this impact attenuation system can tolerate both vertical and horizontal velocities on impact after several time’s collision.Inflatable airbag system can be very light and very easy folded,it takes up less space and has superior performance at impact attenuation,and still very low cost.Airbag system was widely used in interstellar detection,airdrop,unmanned aerial vehicle recycling and automotive airbags.So far,the researchers in the other countries have done a lot of work on the airbag system both in the theory level and the practice level.The Mars Pathfinder succeeded landing on the surface of Mars by using an inflatable airbag system.In our country,the researchers developed several versions of computer code to predict the performance of the airbag system,a series of test programs still need to be done.Based on the situation,this paper mainly studied the fiber material,coating materials and the coating process,we also explored the process to make an full-scale airbag.Several successful experience of foreign and the Mars exploration situation of our country were studied.The Vectran HS fiber was selected as the skeleton materials of the airbag from a number of high strength fiber candidates,the fiber’s tensile,heat resistance and ability to resist acid and alkali were learned separately,the result showed that Vectran fiber has better flex-crack/abrasion resistance with comparable yarn tenacity to Kevlar 29.Vectran retains its full strength upon cooling and actually gets stronger at low temperature,Vectran’s superior flex-crack resistance led to its selection.A coating of low temperature silicone rubber was selected from several candidates,because it retains gas with a thin coating,is readily applied to fabrics,and lends itself well to assembly processes.Its only relative disadvantage is its higher coefficient of friction.this was addressed by application of talc to the inside of the airbag after assembly.On the base of materials studying,a simulating fabric was selected to manufacture a full-scale airbag.The process was divided into three steps,the first step was patterning,since fabric is mostly capable of only two-dimensional curvature,the desired geometry must be approximated by joining many two-dimensionally curved gores.The second step was seaming,the airbag seamed structurally join patterned parts while maintaining gas retention.Stresses tend to concentrate at seams because they elongate less than adjacent material.The last step was sealing,the seams could not keep gas inside because the knee had done some damage on the fabric,so sealing was inevitable for saving the gas.Two different airbag structures were manufactured,one was like a drip,another one was like a cone-shape.Finally,the cone-shape airbag was successful.As a summary,we concluded the researching result,the component level and prototype system level testing would be carried.