
NASA’s SLS rocket carrying the Orion spacecraft
In the previous article we discussed the transitioning burden of human spaceflight to low Earth orbit (LEO) from NASA’s dependency on the Russians to private industry such as SpaceX and Boeing. In doing so, NASA set its sights on manned deep space missions, that will take place over the next few decades.
In the 1960s NASA pioneered human spaceflight with a series of manned spaceflight programs known as Mercury, Gemini and Apollo. Each program was divided into a series of missions building upon each other as stepping stones to reach the ultimate goal of putting humans on the moon. Apollo 11 was the first to achieve this goal, occurring in July 1969. On December 14, 1972 Apollo 17 left the moon, marking the last time humans traveled beyond LEO.
The Path to Mars
In the same way as the manned spaceflight programs from the 1960s and 1970s, NASA has ostensibly laid out a series of potential mission objectives that ultimately culminate in landing humans on Mars in the 2030s. Though these missions are far from guaranteed (and subject to budget cuts), the Space Launch System (SLS) and Orion spacecraft are taking these milestone missions into account during their design phases.

Canadian Astronaut Chris Hadfield monitoring a plant experiment on the International Space Station
The International Space Station
The first step in our journey to Mars is underway right now. Astronauts on the ISS are performing experiments to better our understanding of long term space exposure to the human body. In a document issued by NASA on May 29th, 2014 entitled “Pioneering Space: NASA’s Next Steps on the Path to Mars”, NASA indicated their research specifically targets “decreased gravity affecting bone, muscle, cardiovascular and sensorimotor systems, nutrition, behavior/performance, immunology and the ability to provide remote medical care via telemedic” It also provides us with a test bed for developing better technologies in areas such as spacecraft docking, life support, and extravehicular activity.
The Moon
While NASA may not be landing humans on the Moon anymore, it still provides an excellent place to test long duration, self sustaining systems in a low-risk environment. The first manned missions of the Orion and SLS, slated for 2021-2022, will send humans into an extended lunar orbit to prove the capabilities and habitability of the spacecraft.
Lunar orbit also is valuable for future missions in that the Moon’s gravity is one-sixth of Earth’s. Conceivably, a long duration mission to Mars could be staged and launched from lunar orbit, reducing the fuel requirements to reach cruising velocity to Mars. In this scenario, a manned rocket could be refueled in lunar orbit, increasing the potential payload launched from Earth and decreasing the cost of the mission.
Asteroid Redirect Mission (ARM)

Artist rendition of a potential asteroid redirect mission spacecraft
In addition to human spaceflight, NASA also has projects involving deep space missions to near Earth asteroids (NEAs). To leverage this technology, NASA has decided to attempt a NEA capture and transfer into lunar orbit using robotic spacecraft powered by a solar electric propulsion (SEP) rocket in 2019. Once placed in lunar orbit, astronauts will take Orion to the asteroid, and attempt Extra Vehicular Activity (EVA). This will be the first time a human has set foot on an asteroid, slated for 2025.
The purpose of this mission is complex. From a scientific standpoint, asteroids are extremely old remnants of the early solar system, thus scientists want a closer look at their chemical makeup to help us understand how the solar system was formed. In terms of technology, it will be an impressive feat to both capture and relocate an asteroid, and SEP technology can later be used to transfer cargo to Mars in anticipation of a manned mission, effectively creating a Martian space station before humans ever arrive. Additionally, it will provide an excellent test of Orion’s ability to rendezvous with robotic spacecraft, and give astronauts a chance to test EVA in a low-gravity environment.
Phobos and Deimos
Before landing humans on Mars, NASA may launch a mission to one of Mars’s moons, Phobos or Deimos. Though scientists currently believe they are captured asteroids rather than pieces of Mars broken off, they could provide access to Martian material accrued from millions of years of meteor strikes to the martian surface. The also provide a test environment for landing men in a deep space environment, as Phobos’s gravity is 650 times weaker than Mars’s.

Artist rendition of the first humans on Mars
Mars Landing
Sometime in the 2030s, NASA plans to attempt the first landing of humans on another planet. This will be a culmination of the aforementioned programs, as well as countless hours of development and testing by NASA, partner space programs, and commercial space companies. As of now a mission to Mars will take a minimum 550 days, with more than 95 percent of that time spent in deep space between Earth and Mars. A Martian lander has yet to be developed, but will come to fruition as scientists and engineers learn more about Mars, and human sustainability in deep space.