interesting article — -but it misses a few fundamental points
journeys have two purposes
1 — -Employment — -ie you make a journey and expend energy in doing so, therefore your journey must return with more energy than you consumed, otherwise your effort returns a net loss
2 — -Vacations, where you accept energy loss for the sake of recreation, new knowledge, experiences and so on.
Spending money on journeys does not increase collective wealth, because we live in an energy economy, not a money economy. The article above is focussed on ‘spending’’ — -with no knowledge of what ‘spending’ actually means. Money is nothing more than a token of energy exchange. It is not possible to create money (or resources) by spending it.
space travel must consume finite energy, because it can only be a product of earth based energy systems. Yes, we might discover energy sources on Mars or wherever, but those sources cannot replace energy expended on earth to get there. (And I don’t mean just the fuel in rocket tanks)
Nor will it serve any earth-purpose, because it is too far away to be of use, except (possibly) to make the return flight.
The fact remains, that if there had been anything remotely useful on the moon in earth-use terms, commercial enterprise would have been there decades ago. As it was (and will be) moon explorers returned with photographs and souvenirs. (Which defines a vacation)
Bear in mind that all space-technology is dependent on Earth technology. And Earth technology is dependent on finite resources, which right now are in depletion. Oil, our ultimate driving resource, might have 30 years of output left if we’re lucky. Far less if we start fighting over what’s left — -as is almost certain.
Remove oil, and our industrial system collapses. (And no — renewables won’t fix things) — -but ‘’space exploration’’ is projected into a future where Earth industry cannot exist — -while at the same time advocating spending colossal amounts of money on research or whatever on space development. Much of the fundamental technology needed for deep space survival has not yet been invented or barely thought of, let alone been brought to usable reality.
We must not lose sight of the fact that our sole method of usable propulsion is the same as that used in chinese fireworks 1000 yearsago — -ie burning chemical compounds.
I would suggest that as Earth industrial infrastructure goes into terminal decline, space exploration will be the last thing on our collective minds.
Earth survival might be seen as more important