But one barrier to all these plans is the long travel times necessary with current spacecraft systems.

但是，所有这些计划的一个障碍是，目前的航天器系统的所需旅行时间很长。

At the same time, engineers are seeking to find the cause of helium leaks in the spacecraft's propulsion system.

与此同时，工程师们正在寻找航天器推进系统氦气泄漏的原因。

The New Horizons team is already pushing for another flyby in the 2020s while the spacecraft systems are still working.

“新视野号”团队已经开始推动在21世纪20年代再次进行飞掠，届时该宇宙飞船系统仍在运转。

They worked closely with SpaceX to develop the new spacecraft systems.

他们与 SpaceX 密切合作开发了新的航天器系统。