As Voyager closed in on Neptune, JPL engineers worked round the clock to radio instructions. But they did not know the exact location of the debris encircling the planet.

• “旅行者”向海王星靠拢时，喷气推进实验室的工程师们夜以继日地工作，发送无线电指示，但他们不知道环绕这颗行星的碎片的确切位置。