Science

Science Behind The Martian

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The science fiction novel, The Martian, by Andy Weir is a love letter to NASA and the human desire for space exploration. It is also one of the most plausible and scientifically accurate sci-fi novels in recent memory. Now, this weekend, the movie adaption comes to theaters and we here at the NYRD couldn’t be more excited, but then again we have always been big fans of journeying to the red planet. So to celebrate the opening of a movie that has its foundation in real science, we thought we would take you through some of the technology and aspects that you will be sure to see if you venture to the theaters to watch two-hours of Matt Damon trapped alone, without even a volleyball for company.

Hab Sweet Home
In the book and movie the story’s hero, Mark Watney, is stranded on Mars, but at least he has some things going for him. First of all, he has the habitation module or Hab for short. This is good because we all need a roof overhead, whether it be a one room studio walk up in downtown Manhattan or a multi-room state of the art module on the surface of Mars. Even if development of a real Hab is still a few years off, NASA has been testing crews in the Human Exploration Research Analog (HERA). This analog helps crews learn to work and live together in a simulated deep-space mission. The two-story habitat is complete with living quarters, work spaces, a hygiene module, and a simulated airlock. Currently NASA is running just 14-day duration missions with crews but that will soon be increased to 60-days.

While on Mars, Watney is also forced to grow food in the inhospitable soil of Mars. He accomplishes this by mixing the Martian soil with nutrients and samples from Earth soil, along with his own special brand of compost… eww… Eventually he even yields a full crop of potatoes, but he is not the first person to grow plants beyond the limits of our little blue orb. Vegetables are grown everyday on the International Space Station, but lettuce is the staple of choice for our real-life astronauts. In fact, last year aboard the ISS they even grew Romain lettuce and ate it. That sounds unremarkable, but it is a big step in sustained space living. The vegetables are grown under red, yellow, and green lights in bags of soil mixed with fertilizer, which harvested by the astronauts… eww.

Of course now that Watney has all those potatoes to eat he needs something to wash it down with, and that is where the water recycling system would come in. The one used in the book is a bit more sophisticated than what we have today but still entirely plausible. The Environmental Control and Life Support System aboard the ISS recovers water from sweat, hand washing, tooth brushing, and even urine… eww… However, current methods of water reclamation return only about 85% of pre-used water. The WRS runs water through a series of filters and a centrifuge, since micro-gravity makes separation of gasses and liquids tricky in zero-G. Even better, the technology is being put to use here on Earth, to help developing countries and communities have safe and reusable drinking water.

One Small Breath for Man
Things like water, food, and a roof are only the creature comforts of a Martian stay. In the book and movie Watney needs to work and sweat for every accomplishment he makes, and one of his biggest problems is getting more oxygen. He uses a method of electrolysis to create more for himself, by splitting carbon dioxide to release the oxygen. On the ISS astronauts use a very similar process, except with water but where Watney was the air around him, the ISS just uses water. The excess hydrogen is then bled out into space or pumped back to the Sabatier System which uses it to create more water.

In 2020, the organization will sending a rover to Mars that will test taking in Martian atmosphere and applying electrolysis to produce oxygen right from the air itself. Also, NASA is now looking to get a leg up on their fictional counterparts. Since the writing of the book it has been discovered that water may be more prevalent in the red planet’s soil than originally thought. That would mean they could actually create oxygen straight from the ground.

A Walk on the Martian Side
However, if astronauts want to go outside they will still need to carry the majority of their oxygen with them. The atmosphere of Mars is cold and inhospitable. Mark Watney’s space suit, though it is still bulky and obnoxious is years ahead of the suits employed by astronauts today. Watney spends hours in his suit doing strenuous work and making long journeys. Current suits have too limited of a life span and are way too heavy to allow much work to get accomplished. Yet, NASA is currently testing the Z-2 suit prototype. This is by no means the final design, but the tests being conducted with it will help in the creation of the Z-3 suit, which will then help with the creation of the real suit that astronauts will wear on the surface of Mars.

Our future Martians are going to need a set of banging wheels, though, if they want to get anywhere worth going. We’re talking chrome rims, cherry red chassis, and maybe even a moon roof -considering Mars has two moons. Watney has two rovers in The Martian, which he cannibalizes and alters quite extensively to suit his purposes. NASA is currently testing the Multi-Mission Space Exploration Vehicle (MMSEV). With a top speed of a blazing 6 miles per hour (10 kph), the vehicle has six wheels for stability and is being developed not just for use on Mars, but also on asteroids and moons. Some of the technologies are still begin perfected, such as lighter weight and more powerful batteries, but the MMSEV seems to be pretty close to what Watney uses on his little adventure.

However, one of the biggest problems with going outside on Mars is the dust. The soil in places can be very fine and it gets everywhere. Think, glitter except more annoying. The Martian dust can do everything from muck up sensitive equipment to cover energy-giving solar panels. Dust storms can last for weeks at a time and be as large as countries on Earth. They can even change the face of the planet in a matter of days. Currently the probes we have on Mars can wait out any dust storms before resuming there mission, but humans may not have that luxury. Going weeks without power in the middle of dust cloud that blocks out your solar panels is a death sentence. Watney encounter this situation later in the book, and currently NASA uses Radioisotope Thermoelectric Generators (RTG), which doesn’t rely on solar power, and instead uses the decay of plutonium-238 to generate electricity for Curiosity and the upcoming 2020 rover, but we may not be too keen on having a radiation battery so close to our men and women on Mars.

Getting There
In The Martian, Watney and his crew are brought to Mars by the Hermes, a reusable ion-drive ship that was created expressly for making the round trip from Earth to Mars and back again. Ion thrusters are a very real thing. They use beams of ions -electrically charged atoms or molecules- to create thrust in accordance with momentum conservation, and though NASA has yet to develop a wing of TIE fighters -TIE stands for twin ion engines– it does present a very reliable source of thrust for spacecraft, albeit a very slow one. Relative to chemical engines the ion engine is lumbering, but way more efficient. NASA’s Evolutionary Xenon Thruster (NEXT) has a fuel efficiency of 10 to 12 times great than that of chemical rockets. Unfortunately, it needs to operate in excess of 10,000 hours to accelerate any space-bound object fast enough to reach even the asteroid belt.

Any ion engine will never be enough to get rockets off the ground, but once in space you can turn them on and leave them on, generating acceleration over time. In fact, we already have probes that use ion thrusters, including Deep Space 1, a project so named because I can only assume the geeks at NASA had hoped we could make at least 8 more of them. The Hermes follows the same principal, a small amount of applying a constant thrust to speed the craft up, but it takes the same amount of reverse thrust to slow the ship down, thus braking takes as long as acceleration. It becomes a factor in the movie, but we won’t spoil anymore of it for you.

Our recommendation is that yuo go see the movie, and if anything sparks your interest NASA has a whole lot of information about everything that is going on with our current plans or Mars. They are hoping to have a human on the red planet by the 2030’s, but that is going to take a massive investment of time, money, and passion by the American people, and the people of the world at large. With any luck movies like, The Martian, can help lay the ground work for the enthusiasm we need to get there. All the technological problems and challenges can be overcome, but without a willingness to go, we may never get off the ground.

Humanity needs to be able to fly or we will fall.

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