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Propellantless Sail-Craft Design for the Main Belt Asteroid Exploration Mission

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Propellantless sail-craft design for the Main Belt Asteroid Exploration Mission Liu Yufei (liuyy@[email protected]) Cheng Zhengai， Huang Xiaoqi Qian Xuesen Laboratory of Space Technology 中国空间技术研究院 China Academy of Space Technology(CAST) 中国空间技术研究院 China Academy of Space Technology(CAST) It will conduct further studies and key technological research on the bringgging back of samples from Mars, asteroid exploration, exploration of the Jupiter system and planet fly-by exploration. When conditions allow, related projects will be implemented to conduct research into major scientific questions such as the origin and evolution of the solar system, and search for extraterrestrial life. The Information Office of the State Council on Dec. 27 published a white paper on China's sppace activities in 2016. 2 中国空间技术研究院 China Academy of Space Technology(CAST) The main -belt asteroids 1 mission 2 The solar sail spacecraft 3 Conclusion 2017/2/6 中国空间技术研究院 China Academy of Space Technology(CAST) The main belt asteroid is one of the deep space exploration aims. The solar sail is one of the probable propulsion types. The idea is that the propellantless solar sail can fly in the asteroid belt for a long time and there are abundant valuable targets for the exploration. The Scientific data in the mission can also be compared with results in the DAWN mission. Solar sail is very suitable for the main-belt asteroids mission. 中国空间技术研究院 China Academy of Space Technology(CAST) The mission: Three asteroids in seven years Launch time is around 2020 The Parameters: The areal density is less than 12g/m2 The total mass is 200kg The area is larger than 16900m2 The side length of the sail is about 160m The boom length is about 115m The main exploration target is the Vesta. For optimization of interplanetary transfer trajectory, there are three tra ject ori es sati s fied f or th e seven years conditi on. Table 1. Three chances for the main belt mission. Depart time; Arrival time The first asteroid The second asteroid The total time(year) 2020/8/17;2027/8/6 1703 Barry 1831 Nicholson 6.97 2021/12/30;2028/12/7 1089 Tama 1831 Nicholson 6.94 2021/12/18;2028/9/28 1219 Britta 1831 Nicholson 6.78 中国空间技术研究院 China Academy of Space Technology(CAST) The trajectory of the total flight process in the heliocentric ecliptic coordinate system is given in Fig. 1. The ang ular velocit y c ur ves of the pitch angle and the cone angle are given in Fig. 2. The pitch angular velocity is less than 7deg/day，the cone angular veliillocity is less th an 2d d/deg/day. pitch angle 8 ) yy 6 4 2 0 ngular velocity(deg/da -2 2 aa -4 1.5 5.95 6 6.05 6.1 6.15 6.2 6.25× MJD 1 0.5 the cone angle ar velocity(deg/day) 0 angul -0.5 5.95 6 6.05 6.1 6.15 6.2 6.25× MJD Fig. 2 The angular velocity curves of the pitch Fig. 1. The trajectory of the total flight process angle and the cone angle 中国空间技术研究院 China Academy of Space Technology(CAST) The main -belt asteroids 1 mission 2 The solar sail spacecraft 3 Conclusion 2017/2/6 中国空间技术研究院 China Academy of Space Technology(CAST) The configuration The booms Fold and deployment technology 中国空间技术研究院 China Academy of Space Technology(CAST) the structural mechanics properties of the round, square and leaf sails 中国空间技术研究院 China Academy of Space Technology(CAST) 中国空间技术研究院 China Academy of Space Technology(CAST) Solar Wing 中国空间技术研究院 China Academy of Space Technology(CAST) The sails MN Y X Z MX Fig. 4 . Th e cutti ng and spli ci ng sch emes. skew leaf-out folding method. Two cutting and splicing schemes Several fold methods are compared. are compared . the fold trace , the seams number the smoothness of deployment the angle between the seam the stress concentration direct ion and force direct ion whic h is proportional to the tension 中国空间技术研究院 China Academy of Space Technology(CAST) The booms There are several kinds of booms, we analyze the weight、 the structural mechanics and the fold methods of the booms in the same size. Two tubules, four radius CFRP booms are the last choice. 中国空间技术研究院 China Academy of Space Technology(CAST) The attitude and orbit control subsystem Two mass blocks moving on the booms and four roll stabilizer bars (RSBs) on the top of the booms are the actuators. Fig. 10 The attitud e cont rol acuat ors diagram Actuator parameter data number 2 weight 1.5kg mass block limit position 100m limit velocity 0.5m/s pole length 1.2m pole weight 0.1kg RSBs limit spin angle ±30° limit spin velocity 21°/s 中国空间技术研究院 China Academy of Space Technology(CAST) The communication subsystem Putting the membrane antennas on the surface of the booms as the high gain antennas, the gain is about 30 dBi. The antenna can cover the earth orbit without attitude control. The s lot ant enna array can b e prod uced UiUsing wilireless communitiication as the low gain antenna to get the gain can reduce the weight of the about 6 dBi. cables. 中国空间技术研究院 China Academy of Space Technology(CAST) The main -belt asteroids 1 mission 2 The solar sail spacecraft 3 Conclusion 2017/2/6 中国空间技术研究院 China Academy of Space Technology(CAST) Conculsion Make full use of the advantage and the abundant exploration objects in the asteroid belt, a mission is designed to explore three main belt asteroids in seven years. The solar sail’s areal density is less than 12g/m². To reduce the sail membrane mass, the splicing scheme and the margin strengthen scheme were optimized. Some innovative designs for the booms include the four radius cross-section and the small iflinflatabl etublbules. The wireless communication, the slot antenna and the membrane antenna can reduce the mass of the cables, the traditional antenna. At last, the mission is a hopeful idea and it is feasible based on a lot of current technologies. 中国空间技术研究院 China Academy of Space Technology(CAST) 2017/2/6.
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