1.Institute of Telecommunication and Navigation Satellites, China Academy of Space Technology, Beijing 100094, China 2.National Key Laboratory of Science and Technology on Reliability and Environment Engineering, Beijing Institute of Spacecraft Environment Engineering, Beijing 100094, China
Fund Project:Project supported by the Specialized Research Program for the Protection against Space Debris of China (Grant No. KJSP06209)
Received Date:09 March 2021
Accepted Date:06 May 2021
Available Online:07 June 2021
Published Online:20 September 2021
Abstract:Solar array is a power source of spacecraft, which is often damaged by the impact of micrometeoroids and space debris, resulting in the decrease of output power of solar array. The degradation law of volt-ampere characteristic for spacecraft solar arrays under orbital debris hypervelocity impact is investigated by using a two-stage light gas gun. The volt-ampere characteristics of the solar arrays under different impact velocities, projectile diameters and impact positions are studied. A total of 12 shots are carried out, of which 5 shots are invalid due to the impact of the projectile carrier on the specimen, and 7 shots are valid. The experimental results show that the diameter, impact velocity, and impact position of the projectile all have a great influence on the volt-ampere characteristics, and the damage morphology generated by the ground simulation test is in line with the in-orbit flight test results. The relationship between the failure area of the solar arrays and the area of the spalling area, the perforation area, the kinetic energy of the projectile as well as the impact position are analyzed. It is found that the ratio of failure area to peeling area is between 7 and 37, and the ratio of failure area to perforation area is between 50 and 150. The failure area in the center of the solar cell is significantly larger than that on the edge or at the connection of the solar cell. Failure area of solar array $ \Delta {S}_{\mathrm{S}\mathrm{A}} $ and the cube root of kinetic energy E ($ E=\mathrm{\pi }\rho {d}^{3}{v}^{2}/12 $) is consistent. In order to establish the accurate equation of power loss area with projectile diameter and impact velocity, in this paper it is assumed that there is a power exponential relationship among them, and then solve the undetermined coefficient by the data fitting method. Finally, we establish the power loss $ {\Delta P}_{\mathrm{m}\mathrm{a}\mathrm{x}} $ equation and failure area $ \Delta {S}_{\mathrm{S}\mathrm{A}} $ equation suitable for domestic solar array. The equation will be $ {\Delta P}_{\mathrm{m}\mathrm{a}\mathrm{x}}=0.047d{v}^{2/3} $, $ \Delta {S}_{\mathrm{S}\mathrm{A}}=260d{v}^{2/3} $ when the impact occurs in the center of the cell, and $ {\Delta P}_{\mathrm{m}\mathrm{a}\mathrm{x}}=0.033d{v}^{2/3} $, $ \Delta {S}_{\mathrm{S}\mathrm{A}}=180d{v}^{2/3} $ when the impact occurs on the edge or at the connection of the solar cell. The prediction error of the equation is in a range of 13.3%, and the average deviation is 7.6%. This equation can be used to describe the function relationship between the power loss or failure area of the solar arrays and the diameter, impact velocity and impact position of the projectile under the condition of 0° impact angle. The research method in this paper can be used as a reference for the performance degradation assessment of Chinese spacecraft solar panels under the hypervelocity impact of orbital debris, the established power loss equation and failure area equation can predict the law of power decline and failure area of solar array caused by space debris, and the results have important application value for Chinese aerospace engineering. Keywords:solar arrays/ hypervelocity impact/ volt-ampere characteristic/ power loss equation/ failure area equation/ orbital debris
采用二级轻气炮开展试验, 弹丸形状为球形, 直径为3—5 mm, 速度范围为3—7 km/s. 22.2.试件制作 -->
2.2.试件制作
航天器太阳电池阵组件试件主要由碳纤维铝蜂窝基板、太阳电池片、玻璃盖片等组成, 本文试件制作中, 所使用的所有材料、电池片之间的电路连接形式、工艺与流程, 均与航天器正样产品完全一致[6,19]. 参考航天器工程实际情况, 将6块太阳电池片组合为一个太阳电池片单元, 电池片间距均为1 mm, 碳纤维蜂窝板厚度25 mm. 其中试件1—10太阳电池片尺寸均为30.5 mm × 54.0 mm, 试件11和12太阳电池片尺寸为35.0 mm × 54.0 mm. 太阳电池阵组件试件如图1所示, 太阳电池片尺寸均为30.5 mm × 54.0 mm. 图 1 太阳电池阵组件试件 Figure1. Experimental speicmen: Solar array cells and carbon fiber honeycomb plate.
试验结果如表1所列. 其中, d为弹丸直径(mm), v为弹丸速度(km/s), $ {S}_{\mathrm{h}} $为穿孔面积$\left({\mathrm{m}\mathrm{m}}^{2}\right)$, $ {S}_{\mathrm{c}} $为剥落区面积$\left({\mathrm{m}\mathrm{m}}^{2}\right)$. 试验前后最大输出功率分别为$ {P}_{\mathrm{m}\mathrm{a}\mathrm{x}}^{0} $与$ {P}_{\mathrm{m}\mathrm{a}\mathrm{x}}^{1} $(W), 试验前后最大输出功率之差($ {P}_{\mathrm{m}\mathrm{a}\mathrm{x}}^{0}-{P}_{\mathrm{m}\mathrm{a}\mathrm{x}}^{1} $), 为功率损失$ {\Delta P}_{\mathrm{m}\mathrm{a}\mathrm{x}} $(W). 由于电池阵$ {\Delta P}_{\mathrm{m}\mathrm{a}\mathrm{x}} $与失效面积$ {\Delta S}_{\mathrm{S}\mathrm{A}} $(mm2)呈正比, 利用功率损失, 可以得出$ {\Delta S}_{\mathrm{S}\mathrm{A}} $(mm2). 根据伏安特性测量数据, 太阳电池片尺寸为30.5 mm × 54.0 mm构成的试件1—10太阳电池阵试验前最大输出功率$ {P}_{\mathrm{m}\mathrm{a}\mathrm{x}}^{0} $介于1.79—1.82 W, 由太阳电池片尺寸为35.0 mm × 54.0 mm构成的试件11和12试验前最大输出功率$ {P}_{\mathrm{m}\mathrm{a}\mathrm{x}}^{0} $分别为2.12 W和2.10 W. 太阳电池片为加工精度较高的标准化产品, 因此试验前各试件伏安特性差别较小. 试件No.1和No.12试验前伏安特性曲线, 如图3所示, 限于篇幅, 未给出其他试件试验前伏安特性. 图 3 试件(a) No.1和(b) No.12试验前的伏安特性曲线 Figure3. Volt-ampere characteristic curve of (a) No.1 and (b) No.12 solar arrays before test
铝弹丸超高速撞击太阳电池阵, 太阳电池片的损伤可大致分为3个区域: 中心穿孔区、玻璃盖片贝壳状剥落区、玻璃盖片裂纹扩展区, 如图4—10所示, 给出了试验后损伤形貌、伏安特性曲线. 利用显微镜放大20倍测量试件中心穿孔区域面积. 剥落区的面积通过人工划定区域测量得到, 某些剥落区边界比较模糊, 无法准确界定, 只能人为界定, 如图11所示. 图 4 试件No.1试验后的(a)损伤形貌和(b)伏安特性曲线 Figure4. (a) Damage morphology and (b) volt-ampere characteristic curve of No.1 solar arrays.
23.2.损伤形貌及伏安特性 -->
3.2.损伤形貌及伏安特性
图 5 试件No.5试验后的(a)损伤形貌和(b)伏安特性曲线 Figure5. (a) Damage morphology and (b) volt-ampere characteristic curve of No.5 solar arrays.
图 6 试件No.6试验后的(a)损伤形貌和(b)伏安特性曲线 Figure6. (a) Damage morphology and (b) volt-ampere characteristic curve of No.6 solar arrays.
图 7 试件No.7试验后的(a)损伤形貌和(b)伏安特性曲线 Figure7. (a) Damage morphology and (b) volt-ampere characteristic curve of No.7 solar arrays.
图 8 试件No.8试验后的(a)损伤形貌和(b)伏安特性曲线(因红色圆圈内受到弹托撞击较大, 损失一定功率, 去除弹托影响, 最大输出功率由1.37 W, 修正为1.39 W) Figure8. (a) Damage morphology and (b) volt-ampere characteristic curve of No.8 solar arrays (The maximum output power is revised from 1.37 W to 1.39 W to reduce the effect from sabot impact, since the power in the red cycle has lost caused by sabot impact).
图12为2002年回收的哈勃望远镜太阳电池阵空间碎片撞击后形成的损伤形貌[1,6], 撞击点位置在两片电池片连接处, 类似撞击位置损伤形貌见图9 (No. 11)和图10 (No. 12), 可以看出, 地面模拟试验能够较好地反映太阳电池阵在轨遭受空间碎片撞击时形成的损伤形貌. 图 9 试件No.11试验后的(a)损伤形貌和(b)伏安特性曲线 Figure9. (a) Damage morphology and (b) volt-ampere characteristic curve of No.11 solar arrays.
图 10 试件No.12试验后的(a)损伤形貌和(b)伏安特性曲线 Figure10. (a) Damage morphology and (b) volt-ampere characteristic curve of No.12 solar arrays.
图 11 (a)穿孔区域与(b)剥落区域边界(No.1) Figure11. Measured parameters of (a) perforation hole area and (b) conchoidal area (No.1)
图 12 哈勃望远镜太阳电池阵电池面超高速撞击穿孔形貌[1,6] Figure12. A front-back perforation of the solar arrays exposed on the Hubble space telescope caused by orbital debris impact[1,6].
图 1 太阳电池阵组件试件
图 2 试验参数
图 3 试件(a) No.1和(b) No.12试验前的伏安特性曲线
图 4 试件No.1试验后的(a)损伤形貌和(b)伏安特性曲线
图 5 试件No.5试验后的(a)损伤形貌和(b)伏安特性曲线
图 6 试件No.6试验后的(a)损伤形貌和(b)伏安特性曲线
图 7 试件No.7试验后的(a)损伤形貌和(b)伏安特性曲线
图 8 试件No.8试验后的(a)损伤形貌和(b)伏安特性曲线(因红色圆圈内受到弹托撞击较大, 损失一定功率, 去除弹托影响, 最大输出功率由1.37 W, 修正为1.39 W)
图 9 试件No.11试验后的(a)损伤形貌和(b)伏安特性曲线
图 10 试件No.12试验后的(a)损伤形貌和(b)伏安特性曲线
图 11 (a)穿孔区域与(b)剥落区域边界(No.1)
图 12 哈勃望远镜太阳电池阵电池面超高速撞击穿孔形貌[1,6]
图 13 电池阵失效面积
图 14 电池阵失效面积
图 15 电池阵失效面积
图 16 电池阵功率损失面积与试验数据的关系
图 17 电池阵失效面积
