Will it be possible for us to actually travel to Mars by 2025?

I don’t think so.

And if you are referring to mass travel, in 2100 neither.

I have a game to recommend: google “astronauts leaving for a mission” . You’ll find plenty of photos of smiling astronauts waving as they head to their spacecraft, or as they sit at their locations.

Now try “astronauts returning from a mission 

I anticipate that there are very few, or they are misleading (the epigraph says “returning” but it shows them at the time of the game). But some are sincere, like these:

What is the matter with these people?

That after prolonged exposure to low gravity, or even worse in a zero gravity environment, our muscles atrophy, our blood circulation becomes difficult, and we become semi-disabled like the ones shown in the photo, in need of physical re-education to walk usually. Predictably, space travel promoters have little interest in publicizing these images.

The gravity of Mars is just over a third of that of Earth. It is understood?

That is, it is not impossible that at some point a manned mission will be sent. As in the space race in the 1960s and 1970s, it would be a mere exercise in political competition, to see which country “has it bigger.” When it comes to investigating the planet, robot explorers do it better and much cheaper.

This device, Curiosity, has already been working on Mars for about 10 years… without any human help. He does not feel hungry, nor thirsty, nor does he need to rest (well, every once in a while he stops to charge his batteries). When it stops working it will just stay there; no one will tear their clothes for having abandoned even a human being.

But I suspect that the question comes from the promises to colonize Mars. That’s a ball as big as a house.