Much of the lively chatter about sending humans to Mars before the end of this decade ( and some tech bros were seriously talking about this) seems to have died down. People with lots of money who should know better openly talked about colonisation, the establishment of permanent communities, the inevitability of the Martian conquest - all in the very near future. Someone was even talking about terraforming Mars. Who might that have been?

Perhaps they were mugged by reality - some scientists, such as biologists and physicists - had a long chat about the obstacles and so forth. Perhaps a few only have shortish attention spans, but whatever happened, the focus has shifted again to the Moon. Rightly, it seems to me.

Lets be clear about some of the problems that a manned flight to Mars would encounter. The journey is eight months long and exposure to cosmic rays presents a serious health threat. There is no magnetosphere in space. Landing on Mars is tricky. Building a return space rocket and harvesting the fuel from the Martian world would be an enormous (though feasible) undertaking. The launch to return home must occur in a brief window that occurs only every 26 months. The return launch is fraught with peril - you only have to look at the number of postponements on Earth - and if you have to cancel you might miss the window and be stuck on Mars.

That's just a few. I doubt whether a manned Martian trip will happen before the end of the century, and only if technology has resolved some of the issues, and a costly infrastructure has already been built (robotically) on the Red Planet. It is nice to dream but not at the expense of the brave souls who journey forth.