NASA planned to launch the demo rocket on Tuesday but was stymied by cloudy skies over the Kennedy Space Center and by a boat that wandered into the launch danger zone.

• 美国航空航天局计划在周二发射演示火箭，但是计划被肯尼迪太空中心上空密布的云层和一艘在发射警戒区域四处游逛的船所打乱。