Should space travel be prohibited

Answer 1

Why?

The benefits of operation in space to people on the ground are enormous. Weather satellites, comsats, earth resources satellites, global positioning satellites, and, yes, spy satellites all deliver enormous value to people who never leave the ground. [I admit that I have a direct financial interest in at least three of the above.]

If you mean human space travel, it could be argued that human space travel is not sufficiently useful to be worthy of public funding, but that's not the same thing as prohibiting it. If somebody wants to spend his own money to sit on a controlled explosion, let him have at it, so long as he's not going to fall on someone else in the process.

It's becoming increasingly clear that we need to learn to burn less fossil fuels. Airplanes are currently the most polluting commonly used form of travel (in grams of carbon emissions per passenger per mile). But I suspect that space travel would be far worse.

Hydrogen is a very popular rocket fuel these days. Its "pollution" is water!

I think that they should begin a real manned spaceflight program again, which we have not had since 1972. Everything since then has been a "pogostick flight", leaving the Earth, returning to the Earth, and going to no other astronomical body in between. No one cares if yet another glorified camcorder gets sent to Mars, especially if they don't bother adding a microscope in order to determine the main, #1 answer we are going to Mars to learn... is there now or has there ever been life? They are proposing to send people there, and they don't even know if Mars may contain microorganisms that would make it far too risky to ever return the crew to Earth! I think we should colonize the Moon and use it as a staging area for flights in the future, once it has been determined that no "Reverse War of the Worlds" scenario would keep crews from being able to return.

Someone above implied that space flight using hydrogen fuel is carbon-neutral. But this isn't true. You can't get energy for free, and hydrogen fuel doesn't exist in nature. In order to get energy to make it, you have to burn something else, or split atoms, use solar panels, etc. Since fossil fuels are still the main source of energy, this causes significant carbon emissions. (The same is true of hydrogen-powered cars, although hybrid cars are said to be more efficient than gasoline-only cars.)

Also, someone mentioned manned missions to Mars. As I understand it, such a mission is far too expensive to even contemplate, never mind the fact that the crew would be killed by (gamma radiation?).

Of course, neither splitting atoms nor electrolysis by solar panels is likely to make significant carbon, not that I am one of those who still actually believes in AGW (as opposed by simple natural GW caused by natural forces, which we can see signs of here and there). Money problems can always be solved, and it would be easy enough to put a survival shelter inside the water supply tank, which would prevent solar storms, etc. from killing them. The main problem, technically, is that Mars has too much gravity for an easy LM type landing and takeoff, at least not with a manned crew which would require low-efficiency rockets. The rockets can't be high-performance without turning the crew into splat. Not enough air to land with parachutes and airbags, at least not with a manned crew. That and the fact that it may not be safe to Earth to bring them back, make Mars a poor choice for destination.