The idea of humans setting foot on planet Mars is no longer a question of “how” but “when.”

The American space agency NASA, along with other international space agencies, have reached different milestones that bring the human race closer to the day when men can finally reach the Red Planet. This includes learning more about the planet’s surface, atmosphere and complex geological make-up.

Aside from these, scientists and astronauts also believe that the obstacles of reaching the Red Planet are slowly being addressed. Various rovers and landers have expanded our understanding of life on the planet's surface and that scientists and astronauts are learning to shake off the gravitational hold of Earth. Space agencies from China and Israel have tried to replicate the Martian environment so their astronauts can learn how to adjust in the planet’s harsh environment.

On the other hand, experts have also come up with life-saving tools to survive on Mars. One of these tools includes a fully self-contained closed-loop regenerative life support system for space exploration and planetary habitation. The tool is capable of preserving the human muscle and bone and is radio-protective.

Now that the level of detail in preparing for the conditions that humans will face in Mars is considered to be groundbreaking, to say the least, the question still remains: when can humans finally reach planet Mars?

NASA projected that humans will once more reach the moon in 2024 and Mars in 2033. This was set after US President Donald Trump signed a directive in 2017 which basically instructed the U.S. space agency to bring astronauts back to the Moon "followed by human missions to Mars and other destinations."

However, according to a report, the date to reach the Red Planet could further be delayed considering the massive effort to bring humans to the Moon in the first NASA mission back in the 1960s.

"The Moon is the proving ground for our eventual mission to Mars. The Moon is our path to get to Mars in the fastest, safest way possible. That's why we go to the Moon," NASA administrator Jim Bridenstine said during a recent conference.

Robert Howard, project leader in the development of future space habitats at the Johnson Space Center in Houston, also said that the challenges that will be faced are not so much scientific but political and budget-based.

"A lot of people want us to have an Apollo moment, and have a president stand up like Kennedy and say, we've got to do it and the entire country comes together. If that happened, I would actually say 2027. But I don't think that's going to happen. I think in our current approach, we are going to be lucky to do it by the 2037 date," he said.

The best year that he sees humans reaching planet Mars would be by the year 2060.

Planet Mars
Large bodies of water once existed in Planet Mars. Pictured: In this handout image supplied by the European Space Agency (ESA) on July 16, 2008, The Echus Chasma, one of the largest water source regions on Mars, is pictured from ESA's Mars Express. The data was acquired on September 25, 2005. ESA via Getty Images