The reason a Shenzhou spacecraft takes less time to reach the Tiangong space station compared to a SpaceX craft reaching the International Space Station (ISS) is primarily due to the design and proximity of the Chinese space station, which is smaller, more compact, and often positioned closer to Earth's orbit, allowing for quicker rendezvous and docking maneuvers compared to the larger, more complex ISS; additionally, China has heavily invested in automated docking technology, making the process faster and more efficient.
Key factors contributing to the shorter travel time:
Simplified station design:
Tiangong is a smaller and more modular station compared to the ISS, with fewer modules and less complex internal systems, requiring less time to connect to.
Optimized launch trajectories:
China's space program has likely optimized launch trajectories specifically for reaching Tiangong, potentially leading to a more direct path compared to the ISS.
Advanced autonomous docking technology:
China has invested heavily in automated docking systems, allowing for quicker and more precise rendezvous and docking with the Tiangong station.
Lower orbital altitude:
Tiangong may orbit at a slightly lower altitude than the ISS, reducing the travel distance for the Shenzhou spacecraft.
大陆央视16日晚间新闻联播报导，搭载天舟8号货运太空船的长征7号遥9运载火箭，11月15日23时13分，在中国大陆文昌航太发射场点火发射，太空船顺利进入预定轨道。
约3小时后，天舟8号货运太空船与太空站组合体完成交会对接。16日早上，神舟19号太空人乘组在地面配合下打开天舟8号舱门，开始太空“拆快递”。
15日23时13分，长征7号遥9运载火箭准时点火起飞，约10分钟后，天舟8号货运太空船与火箭成功分离并进入预定轨道，之后太空船太阳能帆板顺利展开，神舟19号太空人乘组也在太空站观看了天舟8号发射实况。
16日凌晨2时32分，天舟8号采用3小时自主快速交会对接模式，成功对接于太空站天和核心舱后向埠，形成组合体。
上午8时26分，太空人蔡旭哲打开天舟8号舱门，进入天舟8号货运太空船。
本次任务，天舟8号货运太空船上行物资总重约6吨，包括太空人在轨驻留消耗品、推进剂、应用实验和试验装置等物资，其中科学应用物资400多公斤，包括实验单元、实验样品、备品备件以及应用消耗物资，并为神舟19号太空人乘组送去蛇年春节的“年货”。
后续，神舟19号太空人乘组将按计划继续开展货物转运等相关工作。