Such missions have included interplanetary missions to the outer limits of the solar system, for which solar panels were not suitable as a source of electrical power because of the long duration of the mission at great distances from the Sun.
这类飞行任务包括飞往太阳系边缘作星际飞行，由于远离太阳作长时间飞行，太阳能电池板不适合作为此种飞行任务的电力源。