By and large, it's cheaper and easier to go with solar power or very low-power radioisotopegenerators like the one that powers the Cassini mission.
大体而言,使用太阳能或者极低能量放射性同位元素发电机,比如运用于卡西尼任务中的,更加便宜和简单。
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There wouldalso be the requirement of a reliable, steady supply of energy, so theuse of radioisotope thermoelectric generators (RTGs) would be preferred.