The Whipple Structure Sensing And Positioning Of Spacecraft Debris With Hypervelocity Impact Manned Capsules

As mankind continues to explore the space environment,the space debris environment is increasingly deteriorating,which seriously threatens the safe operation of spacecraft in orbit.According to the size,it is divided into large debris,small debris,and dangerous debris.For large debris,in-orbit maneuvers are used to circumvent it;for small fragments,protective structures are mainly used;but for dangerous fragments with diameters ranging from 1 cm to 10 cm,neither can be accurately predicted.Its orbital parameters,avoidance in advance,can not effectively protect it.In response to dangerous debris,people propose on-orbit awareness systems that sense,locate,and identify damage patterns.The Whipple protective structure is usually installed outside the bulkhead of a large-scale manned spacecraft,and is fixed by using T-pillars.When the space debris collides with the Whipple structural shield,the generated acoustic emission signals are transmitted to the sensors installed on the bulkhead through the T-pillars,so that there is a certain overlap with the signal that the secondary debris cloud directly hits the bulkhead.The problem of the perception and localization of the Whipple protection structure in space capsule impact space capsule is studied.The main contents are as follows:(1)Timing characteristics of signal transmission on the Whipple structure.There are multiple T-pillars in the Whipple structure.The analysis of the timing characteristics of the next-pillar struts and the correspondence between the signals collected by the sensors and the down-link signal struts are the key to realizing the positioning of acoustic emission sources for the Whipple structural shield.When the distance of the sensor from a T-pillar is less than 1/10 of the shortest distance between all T-pillars,the head of the signal collected by the sensor is transmitted by the T-pillar.(2)Whipple structure super high-speed impact without interference area.When the secondary debris cloud generated by the space debris breaking through the Whipple structural shield impinges on the bulkhead,the acoustic emission signal generated may couple with the signal transmitted to the bulkhead via the T-pillar in the time domain.Through space experiments,the space debris impacts the Whipple structural shield event simulation.The head of the acoustic emission signal collected by the sensor is generated by the secondary impact of the debris cloud,and the upper panel downlink signal will not interfere with the location of the hypervelocity impact.(3)Signal perception recognition on the Whipple structure.Analyze the signal that the sensor may collect from the three aspects of time domain,frequency domain and modal characteristics.According to the difference of the time domain,frequency domain and modal characteristics of the signal,the recognition rate is 90%.When the signal is far from the impact location,the signal is difficult to distinguish from other interference signals.(4)Whipple structural shield impact source location and study the impact of the extravehicular equipment on the positioning results.Firstly,a positioning algorithm is proposed to face the Whipple structural protection screen.The Whipple structure with two lengths of T-pillars is used for experiments to verify the localization algorithm.Positioning accuracy under both pillars meets requirements.The influence of the device on the signal propagation is small,and the main factor affecting the signal propagation is the number of signals passing through the stiffened structure.The reinforced node will not affect the signal propagation.