This is a comment I made on the matter of long term space exploration, viable on
Interplanetary and future deep space exploration entails engaging in technological systems operating outside the relatively very short term periods that revolve together within the confines of a solar day. Taking the latter into account and the fact of limited resources from which to fund further construction of succeeding space vehicles, long term duration of missions increases the amount of factual data that can be gathered. Costs in space exploration would drastically drop if all vehicles other than those made to impact with celestial bodies, or purely solar power dependant, were produced with replenishing capabilities. Technological evolution quickly out paces the life of any space vehicle by the increased output of present day novel invention, catalysed by its own success at efficiency and rendering more for the same investment. Unfortunately, it is not economically viable to totally replace a space vehicle with technology that has materialised a few years after its despatching on a designated goal because the costs are astronomical, even though our species would wish otherwise. If the primary objective in space exploration is to acquire increased amounts of data to explore further afield, relative to being able to fund the whole thing, priority ought to be awarded to increasing technological life span. If the Herschel Space Observatory had been built with the capability of being replenished by helium its life span would have automatically increased. Fuel or helium replenishing space vehicles would be greatly smaller that the larger vehicles they would serve therefore relatively quite low in cost, much lower than replacing the whole thing. On another note, the Herschel Museum of Astronomy in Bath is a small cosy museum and I was very well attended by the very informative staff that worked there. I’d recommend it to anyone to visit.