The Soviet RORSAT radar satellites were powered by a NaK-cooled reactor.Apart from the wide liquid temperature range, NaK has a very low vapor pressure, important in the vacuum of space.

• （相当大的温度范围内仍然是液态，此外，钾钠合金蒸气压非常低，这一点在真空条件下显得尤为重要。）