by Móeiður Þorvaldsdóttir

NASA is planning for its top priority manned mission to Mars to be accomplished by the mid-2030s. This will follow three exploratory missions meant to investigate the long-term viability of humans surviving on Mars. Furthermore, these missions are necessary to develop and test necessary systems and equipment such as life support and spacecraft controls. These missions rely on the completion of NASA’s Space Launch System (SLS), the construction of which began in November 2014. SLS is a launch vehicle that will pave the way for more massive payloads than ever before. The manned mission is divided into two stages: the first one is planned to reach Mars’ moon Phobos by 2033 whilst the second part is expected to reach the surface of Mars by 2039.

A mosaic of Mars created from over 100 images taken by Viking Orbiters in the 1970s. Valles Marineris, the canyon seen in the centre, is the largest canyon in the Solar System. Image credit: NASA

The Plan

The three exploratory missions are named Earth Reliant, Proving Ground, and Earth Independent. Earth Reliant has already begun and is expected to continue until 2024. Proving Ground will start in 2018 when the Orion spacecraft will be launched on a lunar orbit using the SLS. The SLS in combination with other spacecraft has the capacity to help astronauts travel farther into space than ever before. The SLS has also been proposed as a launch vehicle for Uranian probe and Solar Probe 2, missions to Uranus and the Sun currently being planned. Orion’s first trip to the Moon will be unmanned, but, if this unmanned mission is successful astronauts will man Orion on a similar journey. This stage will test the capabilities of NASA’s team of astronauts, scientists and engineers as they attempt to redirect an asteroid into lunar orbit and extract samples for testing upon arrival back on Earth. Earth Independent will start with an unmanned trip to Mars in the 2020s that will test the capabilities of the vehicle for entry, descent and landing. It will also provide an opportunity to collect samples from the surface of Mars. This is NASA’s final exploratory mission, after which astronauts will begin their journey to the Red Planet.

Reaching Phobos

The trip to Phobos will require four launches of the SLS. The first of the four launches will carry a space tug which will use Solar Electric Propulsion (SEP) and two chemical propulsion payloads. The chemical propulsion payloads will be used to get the vehicle out of Earth’s influence and to land the vehicle on Phobos. The second SLS stage is planned to carry another SEP tug and the Phobos base. The Phobos base will be settled in order to provide a habitat for humans once on Phobos. It would also be possible to transport the base to different locations on Phobos if required. The next SLS launch will carry a deep-space habitat that is similar to the Phobos’ base as well as launch the vehicle into orbit around Mars. Finally, the last SLS stage will send a crew of four astronauts to Mars on board Orion. The Phobos Transfer Stage will ferry the astronauts down to the base in 2033 where they will remain for about 300 days. The astronauts will then return to Earth.

The Orion flight test crew module. Image credit: NASA

The Trip to Mars

Getting astronauts onto the surface of Mars will involve a further six SLS launches. This final part of the mission involves getting a lander in orbit around Mars. The lander will include a Mars Ascend Vehicle that would bring the astronauts to Mars’ surface and then back to earth. The vehicle will be equipped with retrorockets and a drag-increasing Supersonic Inflatable Aerodynamic Decelerator (SIAD) instead of the older parachutes that offer less drag. The lander will support a crew of 2 for 28 days or 4 for 6 days.

Possible Complications

A manned mission to Mars is not an easy feat as there are many things that can go wrong. NASA will rely heavily on the ISS for gathering more information regarding possible health risks of the astronauts and for the testing of equipment. It is necessary to construct Orion in such a way that the astronauts are safe from radiation in interplanetary space, as well as preserving their muscles, bones and internal organs in microgravity for a long period of time. A 300 day stay on Phobos, a moon that has a gravitational pull equivalent to 0.05% of the Earth’s may impact astronaut’s bodies due to loss of muscle mass and bone density. Furthermore, for a trip to such a distant destination, there must be no flaws in any of the launch systems, propulsion systems or space tugs. All systems involved must be tested rigorously before they can be used in order to prevent any complications. Even with the many precautions taken and with rigorous testing, an unmanned mission is necessary prior to the manned missions at each stage in order to minimize the risk of things going wrong.

Humanity has not ventured beyond low-Earth orbit since the Apollo 17 mission. This will be the next big step in space exploration and may be the beginning of humans colonising other planets. Moreover, this will offer the opportunity to study the surfaces of Mars and Phobos further as well as the effects of space travel on human anatomy. If this series of missions is successful, NASA’s scientists hope this will mark the beginning of regular missions to Mars.

Artist concept of NASA’s Space Launch System (SLS) 70-metric-ton configuration launching to space. Image credit: NASA