Humankind has cast an eye toward another “giant leap” forward nearly half a century after the United States’ Apollo 11 spacecraft delivered humans to the moon for the first time.

The U.S. National Aeronautics and Space Administration (NASA) is planning to put a manned spacecraft into orbit around Mars in the 2030s, before sending humans to explore the red planet.

Similar in size to Earth, and relatively close, Mars is widely considered as the most promising and realistic candidate planet for manned space exploration.

The planet, however, is more than 50 million km away from Earth even when their orbits are at their closest. With a round-trip journey taking multiple years, a realistic approach to the journey calls for fuel and other required materials to be made available along the way.

NASA, therefore, plans to build a space station to put in orbit around the moon by the end of the next decade as a supply base for future journeys.

It is also developing a spacecraft, named Orion, which is capable of carrying a crew of four, and making preparations to build a Space Launch System, a powerful rocket to carry Orion into deep space.

Orion needs to be equipped with a variety of systems to support the long journey to Mars, which would take more than a year from a starting point in the moon’s orbit.

NASA also envisions building a base on Mars for resource exploration.

The Mars program will be promoted in close cooperation with various aerospace companies. For example, Lockheed Martin Corp. is proposing to build a Mars-orbiting base, the Mars Base Camp, to accommodate six astronauts. Given the U.S. company’s involvement in the development of Orion, it is considered likely that NASA would support this idea.

Space Exploration Technologies Corp., a U.S. aerospace venture business known as SpaceX, envisions developing a large-scale reusable spacecraft capable of carrying more than 100 Mars settlers per flight, the first of which is reportedly planned for 2022 at the earliest.

There are also space projects elsewhere. The International Space Station (ISS) orbiting around Earth at an altitude of 400 km will be privatized over time.

Bigelow Aerospace LLC, another American space technology start-up, is planning to create a private sector-run space station that will serve as a “space hotel” consisting of balloon-like modules for tourists from Earth.

There are a number of hurdles to overcome if the challenge of completing long space journeys is to be realized. Among the issues of vital importance is how to secure sufficient amounts of food, as spacecraft can only carry a limited volume of materials.

The production of vegetables in space was proved possible when Japanese astronaut Kimiya Yui grew lettuce using a light-emitting diode lamp, water and fertilizer during his stay of nearly five months aboard the ISS in 2015. Self-sufficiency may be achieved if a wide variety of food can be produced in space.

A system to allow the reuse of water and air is also a must. In addition, excrement can be processed into fertilizer for food production or into energy, using microorganisms, to run systems on a spacecraft.

Advances in 3-D printing technology are expected to be a boon for journeys between Earth and Mars because tools and parts to make repairs can be produced on demand.

The outer shell of a spacecraft also needs to be designed to reduce astronauts’ exposure to harmful cosmic radiation, while robots may be developed to replace humans on dangerous spacewalks.

To ease the stress that comes with prolonged time in a close, isolated space, artificial intelligence is expected to play an important role as an “adviser” or “conversation partner” for astronauts.

Donald Trump’s rise to the U.S. presidency may also put the Mars program in jeopardy. Some worry that the huge cost involved in such a project, including funds for the ISS, may not be palatable to someone with his business background.

An international forum will be held in Japan in the latter half of 2017 to discuss manned space exploration.

Although Japan has yet to decide whether to participate in a joint international program for the manned exploration of Mars, the country has been promoting the development of necessary technologies.

In the absence of its own manned spaceship, Japan currently relies on Russia to send astronauts to the ISS. Japan, however, has accumulated technologies to develop such a spacecraft through activities in its “Kibo” experiment module attached to the ISS.

The Japan Aerospace Exploration Agency (JAXA) is developing the upgraded model of the “Konotori” series of unmanned cargo ships for launch in fiscal 2021. The new transporter, code-named HTV-X, will be designed to be capable of unmanned flight.

“It is technologically possible to give spaceship-like functions to the transporter if it is equipped with a life-support system,” a JAXA official said.

Together with a large H-3 rocket currently under development, the transporter is expected to help expand Japan’s activities in space.

Russia, which has a proud history of space exploration and in 1961 was the first country to put a person into space, is planning to send humans to the moon by 2030 and build a lunar base.

China is looking to construct its own space station by around 2020. As part of preparations, the Asian power in October sent two astronauts to a space laboratory orbiting Earth for a 30-day stay and succeeded in lifting a large Long March 5 rocket into space the following month.

A Japanese expert familiar with China’s space program said the heavy-lift rocket has given the world’s second-largest economy “all it needs to build a space station.”

Interest is growing about whether, or how, China will be involved in any potential exploration of Mars.

Humans are moving into another stage of space exploration, working toward a time when the indelible words of American astronaut Neil Armstrong (1930-2012) may again be truly apt to use.

“That’s one small step for man, one giant leap for mankind,” said the commander of the 1969 Apollo 11 moon landing mission after climbing down the ladder to become the first person to set foot on the surface of the moon.

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