Moving to Mars? Reality of Martian Living.

Courtesy NASA

Mars is going to be news in a big way in the near future, with a new NASA mission.  In keeping with my recent space theme I thought I would bring reality to something I read a couple of weeks ago.  This article wasn’t involving the NASA rover, but a more ambitious effort to put a man on Mars... permanently.  But, I'll get to that in a moment.

A new NASA rover, Curiosity, will be landing on Mars with a mission to determine if the planet has, or ever had, microbial life.  Everything we know from previous missions leads us to believe the surface is a lifeless, cold, barren, desert.  There is evidence of liquid water, but no proof.  There has been speculation of microbial life, but nothing conclusive. 

Living on Mars has been the stuff of science fiction since Edgar Rice Burrows penned his pulp fiction classic “A Princess of Mars”.  Sending a manned mission to Mars began the second Neil Armstrong planted his foot on the dusty surface of the moon.  At that moment, I’m sure that someone in mission control said: “Can’t wait to see them step on Mars.”  The moon, after all, was only supposed to be a stepping-stone.  When it was determined that Venus was inhospitable to all forms of life, as we know it, Mars became the obvious choice for a manned mission.  Unfortunately, every time the idea is brought up, it’s shot down, probably for good reason.

I think sending a human to explore the surface of Mars should be a priority when it comes to manned space flight.  It is a worthy mission with some extremely challenging engineering obstacles.  The reality is that it will probably never happen with our current technology, but that doesn’t stop people from dreaming big.  Now I could write a novella on this subject, but that would get tedious in blog format, so I’m going to break it up into two parts.  The first will focus on the journey, and the second will concentrate on actual colonization.

Let’s start with getting a spacecraft to Mars.  It will cost a ton of money to start with.  It will require a spacecraft large enough to accommodate astronauts (in the case of Mars One it’s four, and NASA has toyed with six to eight) for the entire trip.  In the case of a NASA mission, it would be three years round trip, with eighteen of those months spent on the surface.  

Earth and Mars are separated by millions of miles, and any expeditions between the two planets have to be timed precisely.  If you launch at the wrong time your journey could take significantly longer than if you had waited.  

The idea of waiting until the travel distance is ideal is something that is foreign to most of us.  The distance between New York and London is 3,458 miles by air (provided the carrier is flying direct).  This distance may vary by inches year to year, but isn’t likely to drastically change (unless you believe Ronald Emmerich).  This isn’t the case when it comes to planets.  Mars is, at its closest calculated distance, 54.6 million kilometers (km) from Earth (according to Space.com).  The reason why I say calculated is that no one has actually observed this in practice.  The furthest it can be from Earth is 401 million km.  The average is 225 million km.  It takes light roughly 14 minutes to reach Earth from Mars, and can take up to 22 minutes.  It means that, unless you time it right, you could take sixteen months, or more, to reach your destination.  That is why missions are timed to make the travel time as short as possible.  

They are developing VASIMR rocket engines to decrease the travel time to around forty days, but there are issues that make this kind of propulsion tricky.  The primary obstacle is power.  They are experimenting with a 200 kW engine configuration (two 100 kW engines), however the entire ISS space station (where they would run the practical tests) produces a maximum 200 kilowatts of electricity using its solar panel array.  Obviously, you can’t use it continuously or there would be no power for the rest of the vital electric components, so you use a battery system that charges until it’s full, and then you can use the engines until the batteries die, or you can bring along a nuclear reactor capable of generating enough electricity to run everything. 

Nuclear reactors have been considered as sources for rocket propulsion since 1952 with the NERVA project.  One of the major drawbacks is radiation.  Space is a rather hostile environment, and exposes the crew to more radiation than they would normally get on Earth.  If you add a reactor in close proximity to the crew, it makes it even more dangerous.  In order to reduce the exposure to radiation you have to use adequate shielding and distance to separate the crew from the reactor.  The shielding required for this increases the overall weight significantly.  The NERVA rocket weighed 393,130 pounds, and required a Saturn V rocket to launch it into space.  Technology has improved significantly since the early 1970’s, when the project was cancelled, but a reactor would still be a lot of weight.  There is also the potential for a core meltdown or catastrophic rocket malfunction that could contaminate a large area with radioactive debris.  That doesn’t preclude the use of nuclear powered rockets, but it presents a significant environmental hurdle.

Radiation exposure isn’t the only health hazard crews will face.  Microgravity and zero gravity can cause health issues too.  There is a reason NASA will only take people in good health.  The moment you enter space your body begins to adapt to its environment.  Since bones are only as strong as they need to be, your body begins to reduce bone density, because there isn’t any reason to have strong bones when you’re weightless.  Even after you arrive on Mars, the gravity is such that your bones continue to lose density.  All that extra calcium builds up in deposits in your kidneys, and you get kidney stones.  If the stones are too large for you to pass, you could die.  This is one of the primary reasons for the ISS crews being limited to six months in space.  The other is muscle atrophy.  Because your body isn’t fighting gravity, weight isn’t an issue (objects have mass, but weight is dependent on gravity).  This means that you don’t have to exert yourself as much in space as you would on earth.  Since your muscles are only as strong as they have to be, you begin to lose muscle mass.  Crews have to stick to a comprehensive exercise program the entire voyage, and even then, some atrophy is inevitable.

Getting to Mars is easy compared to landing.  Putting a spacecraft on the darned thing is next to impossible, particularly for a manned mission.  Let’s start with the atmosphere.  The “air” (we’ll use that term loosely) on Mars is a hundred times thinner than on Earth.  It’s thick enough that you have to deal with it, but not thick enough to allow techniques that work on Earth.  The thin atmosphere won’t slow you down enough if you try to use air-breaking maneuvers alone, and parachutes won’t be enough either.  You can’t rely solely on rockets like the Apollo missions used on the Moon, for the very reason that there is an atmosphere.  Forget about using the airbag techniques of previous Mars rover missions.  There are simply too many G’s encountered to allow a human to survive that method.  You can’t land a shuttle like spacecraft on the surface, because there wouldn’t be enough lift.  At the surface, the air on Mars is roughly the same density as Earth’s at nearly 60,000 feet.  Most planes can’t fly that high because of the lack of airflow over the surface of the wing, not to mention that there aren’t any suitable runways on Mars in the first place.  You would have to use multiple techniques to land safely on the surface of Mars.

Mars rover Curiosity. Courtesy NASA

Curiosity will be the largest rover ever to land on the surface of Mars.  It is roughly the size and weight of the average passenger vehicle.  The landing sequence is almost as elaborate as anything Rube Goldberg could imagine.  First, the entry vehicle will use the atmosphere to slow it down.  Then it will deploy the largest supersonic parachute ever designed.  Then it will use rockets to slow itself down further, and then twenty meters above the surface the rover will be lowered using a sky crane.  If there is one error in that entire chain the $2.5 billion project will come to an abrupt crushing end.  This is all to make sure a well-engineered machine can roam around on the surface.  It would be even more complicated if there was a human on board. 

Manned missions increase the difficulty significantly because of the increased weight of the landing craft, and the potential for loss of life.  You have to be able to get the lander and crew on the surface intact.  The sheer volume of food, supplies, fuel, equipment, spacecraft, and crew make a safe landing extremely challenging, but it is entirely doable.  You would have to be extraordinarily careful in the final 20 or so meters from the surface, which is why Curiosity is using a sky crane to lower it.  The reason is all the dust that is kicked up using rockets.  

Mars is a dusty place, and it’s everywhere, and gets on, and into, everything.  We don’t know exactly what the effects of Martian dust will be on people, but there have been studies on Lunar dust.  Lunar dust became an issue on Apollo 17 when the astronauts who landed on the surface, tracked the fine powder into their spacecraft, and it caused respiratory problems all the way home.  Manned missions would need to have OCD when dealing with it, and a permanent colony would have to make it an official religion (complete with prayers and goat sacrifices).  If they didn’t, equipment would cog/break or wear unusually fast.  There is also evidence to suggest that the soil is slightly pH basic (caustic) causing more issues.  Unfortunately, a sky crane would be impractical with a spacecraft large enough to service a manned crew for eighteen months, so you are left with using a main thruster all the way down to the surface.  You would just have to deal with the aftermath as best as you could.

The easiest way I can see to getting there safely is by having two spacecraft.  One would consist of a heavily shielded nuclear reactor and engine assembly at the end of a very long boom which would act as buffer between the crew and the reactor.  That way the reactor could be left in a parking orbit above Mars, and you wouldn’t have to deal with the extra weight during landing.  The orbiter could also contain a living section that could rotate on its axis and provide the crew with some form of artificial gravity during the journey there, and mitigate some of the effects of the zero gravity environment of interplanetary space.  This, of course, presents its own set of obstacles due to the torque caused by the rotation, which would affect the spacecraft’s navigation.  The orbiter could also function as a communications satellite, and orbital instrument platform (like have a space telescope or surveying equipment on board).  The lander could consist of enough room to accommodate all the supplies necessary to complete the mission on the surface, and possibly even be configured to provide larger living spaces after landing (similar to RV pullout’s).  This way you aren’t eating up precious cargo space for the food, supplies, and fuel used for the interplanetary portions of the voyage in vehicle used to land on the surface.

Since the atmosphere of Mars is primarily CO2 (95.5%), you can use the time on the surface to separate the oxygen for use as fuel for the return trip, as well as providing enough O2 to supplement the astronaut’s air mixture while on the surface, and the return trip to Earth.  The reason I say supplement is that 100% O2 can cause health problems if is breathed over a long period.  Too much of a good this can be bad for you.  

I would jump all over this, if I liked the idea of being cooped up for three years in a small metal tube with people who may not get along, but I get tired of being cooped up when I'm on a transatlantic flight.  I can't even imagine two to nine months in a confined space.  If I could stand the trip I would love to be one of the first people to step foot on Mars, but I wouldn’t want to make it my home.  It would be more like a working vacation.  Visiting would be nice, but moving there is something entirely different.  But, residency is a topic for another day.