Science fiction aficionados and techno-freaks have deluded themselves into seeing a future in space travel for humans. Some see it as necessary for the survival of the human race. Disagreeing may seem to be a being a spoilsport but we should turn away from these unrealistic endeavours. We have to face the unpalatable fact that the Earth will become unlivable one day and our descendants will all die off. Each of us do die off even though we fantasize about living on somehow while our bodies fail to continue living. We will die. The earth will die too.
We have to recognise that we are consuming the resources of the earth at an unsustainable rate as if we occupy multiple worlds. The pollution of our atmosphere is seen as the most immediate threat because our polluting gases will lead to an unlivable climate and sea level rise will consume most of our capital infrastructure. If we are going to delay our demise we must stop the pollution of our atmosphere with gases that reduce the emissivity of our planet which leads to global unlivable climate change. The plans for rocketing people to the Moon to prepare a base, continuing to Mars, and one day voyaging out to find another habitable planet (not yet discovered) are grandiose and counter our immediate survival needs. There is a need to do the arithmetic on the engineering and victualing of such a plan. The idea of engineering Mars to suit us is refuted by those who would see the need to make the Earth habitable instead.
The scale of rocketry for these ideas requires an enormous collection of energy fuels for this plan. This requirement for energy must involve the production of an excessive amount of greenhouse gases. We need to quantify this to grasp the enormity of this mis-allocation of our depleting resources. The materials required for the rockets and the rocket fuels necessary imply such large enterprise must automatically mean too much consequential polluting byproducts.
Human physiology is not suited for space travel. We have an inbuilt need to learn about our cosmos but we now have the ability to use robots to do that work much more efficiently. There is no need to send scientists into space when robotic technology can do a much better and more efficient job.
The scientist, engineers, and technicians working on this space nonsense must be diverted to attack the problems facing us with the continuance of consumptive polluting activities. I have a thought that this would be a better path to our limited future.