Comet Interceptor (Comet-I) was selected in June 2019 as the first ESA F-Class mission. In 2029⁺, Comet-I will hitch a ride to a Sun-Earth L2 quasi-halo orbit, as a co-passenger of ESA's M4 ARIEL mission. It will then remain idle at the L2 point until the right departure conditions are met to intercept a yet-to-be-discovered long period comet (or interstellar body). The fact that Comet-I target is thus unidentified becomes a key aspect of the trajectory and mission design. The paper first analyses the long period comet population and concludes that 2 to 3 feasible targets a year should be expected. Yet, Comet-I will only be able to access some of these, depending mostly on the angular distance between the Earth and the closest nodal point to the Earth's orbit radius. A preliminary analysis of the transfer trajectories has been performed to assess the trade-off between the accessible region and the transfer time for a given spacecraft design, including a fully chemical, a fully electric and a hybrid propulsion system. The different Earth escape options also play a paramount role to enhance Comet-I capability to reach possible long period comet targets. Particularly, Earth-leading intercept configurations have the potential to benefit the most from lunar swing-by departures. Finally, a preliminary Monte Carlo analysis shows that Comet-I has a 95–99% likelihood of successfully visit a pristine newly-discovered long period comet in less than 6 years of mission timespan.

彗星拦截器（Comet-I）于 2019 年 6 月被选为欧洲航天局的第一个 F 级任务。2029年⁺，彗星-I 将搭便车前往日地 L2 准晕轨道，作为欧空局 M4 ARIEL 任务的共同乘客。然后它将在 L2 点保持空闲，直到满足正确的出发条件以拦截尚未发现的长周期彗星（或星际天体）。因此，彗星 I 目标无法识别的事实成为轨迹和任务设计的一个关键方面。论文首先对长周期彗星种群进行了分析，得出的结论是，每年应该有 2 到 3 个可行的目标。然而，彗星-I 将只能访问其中的一些，主要取决于地球与距离地球轨道半径最近的节点之间的角距离。对传输轨迹进行了初步分析，以评估给定航天器设计（包括全化学、全电动和混合推进系统）的可及区域和传输时间之间的权衡。不同的地球逃逸选项对于增强 Comet-I 达到可能的长期彗星目标的能力也起着至关重要的作用。特别是，地球领先的拦截配置有可能从月球摆动偏离中受益最大。最后，初步的蒙特卡罗分析表明，彗星 I 有 95-99% 的可能性在不到 6 年的任务时间跨度内成功访问一颗新发现的原始长周期彗星。不同的地球逃逸选项对于增强 Comet-I 达到可能的长期彗星目标的能力也起着至关重要的作用。特别是，地球领先的拦截配置有可能从月球摆动偏离中受益最大。最后，初步的蒙特卡罗分析表明，彗星 I 有 95-99% 的可能性在不到 6 年的任务时间跨度内成功访问一颗新发现的原始长周期彗星。不同的地球逃逸选项对于增强 Comet-I 达到可能的长期彗星目标的能力也起着至关重要的作用。特别是，地球领先的拦截配置有可能从月球摆动偏离中受益最大。最后，初步的蒙特卡罗分析表明，彗星 I 有 95-99% 的可能性在不到 6 年的任务时间跨度内成功访问一颗新发现的原始长周期彗星。