The salaries are not merely money being cycled around in the economy if the labor being paid for results in the scientists not having time or inclination to produce other labor. Furthermore, it is likely that the resources launched off of the planet could have been used for something else.

Whether or not it is equivalent to the broken window fallacy really does depend on subjective assessments of the value produced by the missions. However, it is also worth noting that even the broken window fallacy is not some universal law, and relies on its own assumptions. In certain market failure conditions destroying something and fixing it as a mechanism for increasing the velocity of money could have a net benefit.

Although it is very useful to distinguish between the real economy and money transactions as though money is an abstraction for resources being traded around, the best policies also acknowledge the existence of money, as well as friction in the economy.