CS272 – Tech A

A key question when proposing a mission to Mars is the notion of coming home to Earth. This notion would not be viable with the resources available on Earth, such that the amount of fuel required for a round trip to Mars would be very hard to handle for such a long distance. Thus, the only feasible option for such a return would be to find or manufacture the fuel for the home trip while on Mars. With articles discussing the technologies and resources for fuel on Mars, it seems like this will be the way to go when planning a Mars trip, and making it not just a one-way grave for astronauts.  There are two major possible options for the creation of fuel on Mars. One using the Martian atmosphere, and the other using nuclear elements found on the planet’s surface.

While the Martian atmosphere is quite different from our own (not to mention much thinner),  and is mostly comprised of carbon dioxide (CO2). There are two different methods that fuel can be produced by this. One is the electrolysis of the CO2 into carbon monoxide (CO) and oxygen (O2). The carbon monoxide is used as a fuel and the oxygen could be used elsewhere. This is a fairly simple method of making fuel with only the elements of the atmosphere. The other method would be to create a Sabatier reaction, “reaction of hydrogen with carbon dioxide at elevated temperatures and pressures in the presence of a nickel catalyst” (“Sabatier Reaction”, Wikipedia), which would output methane (CH4) and water (H2O). This method seems to be a little more involved but also produces water in the end, which is crucial for sustaining life on Mars. One rover, from a proposed NASA mission, was designed to used the first method to create a “self-refueling hopper” to sustain itself on the planet. I believe that this could be the method to get home from Mars.

The nuclear option for harnessing fuel on Mars would be through its rich Thorium (Th) deposits. “Any cubic meter of Earth, Moon or Mars has enough Th-232 to run a profligate American’s energy life for several years” (Alexander Cannara, IEEE Life Member). There are also detailed maps of the Martian surface noting the Thorium density in parts per million. Thus the quantity of the Thorium cannot be disputed, unlike the method required to create a nuclear reaction with it. Thorium is not inherently fissile, meaning it cannot start or sustain a nuclear reaction. It would require some “weapons-grade material” to start the reaction. This is something such as Plutonium-239 or Uranium-239, which we might have to bring with us from Earth. The unique part about this process is that Thorium will decay into Uranium-233 from the nuclear reaction which is a fissile material. Thus, once the Thorium decays to a certain point the external Plutonium and Uranium becomes unnecessary, and the process becomes self-sustaining. This would all be great in theory, and possibly even for fuel on Earth, but at the current time it seems that the technology is not there and much more complicated than methods using the Martian atmosphere.

In the end I feel that using the CO2 from the atmosphere will prove to be the ideal way to fuel both living on Mars and the trip home, and the notion of it being a one-way trip should seem out of the question even with today’s technology.

Sources:

• http://www.lpi.usra.edu/meetings/robomars/pdf/6098.pdf
• http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1559325
• http://www.geoffreylandis.com/propellant.html
• http://spectrum.ieee.org/tech-talk/energy/nuclear/is-thorium-the-nuclear-fuel-of-the-future
• http://energyfromthorium.com/forum/viewtopic.php?f=6&t=759
• http://www.ieer.org/fctsheet/thorium2009factsheet.pdf

It is difficult to imagine long stays on Mars, with its uninhabitable climate, unbreathable atmosphere composition, and lack of anything living (as far as we know). Instead of requiring residents to keep their space-suits on at all times, perhaps it would be better to convert the planet into a more comfortable place. If it were possible, terraforming Mars would make it a place suitable for life.

Reengineering the Martian atmosphere is not a new idea. It has been proposed in science fiction on numerous occasions. There are some pages on the NASA website, which were apparently last modified 9 years ago which roughly explain the process, however, they explain only one potential way of converting the atmosphere, which is creating chlorofluorocarbons using resources from the air and soil, which act as greenhouse gases to heat up the planet.

Three years ago, IEEE published an article in their Spectrum Magazine. They also make the assumption that inducing global warming is necessary to make the planet livable, which is probably true, as the temperature is very much below freezing, even to the point where a lot of its CO2 is solid.

If we could start the global warming process, some of the dry ice could sublimate, thus increasing the density of the atmosphere and causing a more potent greenhouse effect. Some scientists predict, depending on the method, that the process of raising the temperature of Mars could take five to ten decades.

One of the methods suggested is similar to that of the old NASA web page, creating heavy halocarbons to act as a greenhouse gases. It still remains to be known though if we can generate enough to effect the change of a whole planet’s atmosphere in a significant enough way.

Another idea, proposed back in 1981 by James Oberg is to use huge mirrors to reflect sunlight onto the dry ice-covered poles. It may be possible, but it sounds less likely than the first option. Can we even fabricate mirrors big enough, and if so, how easily could we transport them to Mars?

Another idea, that is even more “out there”, is to use nuclear-powered rockets to direct astroids to crash into Mars. This sounds like science fiction, but who knows?

Once the planet is warmer and the atmosphere has more carbon dioxide, we can potentially start to grow plants there. Another issue is that the amount of nitrogen in the atmosphere is very low compared to Earth (2.7% vs. 78%). Some scientists believe the ground there may contain enough nitrates to support future plant life, but it is yet to be known.

If we ever figure out a good method of terraforming, it definitely seems like a good idea. The benefits of having another place for humans to live are immense, and the study of warming the Martian atmosphere may help us find how to slow the warming of our own.

One of the biggest issues in habiting Mars is obtaining a supply of water.  In his book titled Mars: A Warmer, Wetter Planet, Jeffrey Kargel outlines the human need of water.  He states that any single human might require up to 4kg of water per day for drinking.  So theoretically, a 14-day mission on Mars might require over 600 kg of water for the health of the astronauts alone.  However, hydration is not the only use for water in space.  In an atmosphere mainly filled with carbon dioxide, electrolysis could provide a means to obtain oxygen.  (Electrolysis is a process by which water is transformed into oxygen and hydrogen gas through the use of an electrical current; read more about it here).  According to Kargel, a 10-person base would require about 100 kg/day of water to use for this function.

Long-term, self-sufficient settling of Mars would also require a steady production of agricultural elements (such as food, medicines, etc).  Kargel estimates that the same base would require another 100 kg/day of water to account for the vegetation.

Overall, a short, 14-day mission on Mars would then require approximately 2 tons of water for the support of the astronauts on board.  Keep in mind, however, that this water is only to be used on the planet; the astronauts will need additional water for the months of travel to and from Mars.

Where will the astronauts obtain water?  Well, there are two main options:

1.  Bring it with them – The ships will need to have enough room and power to carry this payload out of Earth’s atmosphere and into Mars.  There is a narrow margin of error, and water will become a limiting factor to the length and completion of the mission.

2.  Find it in somewhere space – Asteroids have been known to commonly carry ice and could potentially be mined to provide large quantities of water.  Naturally, such an operation carries controversial risks which may outweigh the sought outcome.  The logical choice would be to find water where the mission will take place: on Mars.

We know from both satellite images and rover exploration that Mars, like Earth, has polar icecaps which are made of frozen water, and there exists evidence that water used to flow on the surface in liquid form.  Due its temperature and pressure, the surface of Mars no longer hosts flowing water.  However, scientists believe that because of the way the ice caps were formed, there still exists liquid water under the surface.

I propose that we exploit this resource and find all of the water we need at the polar icecaps.  Mining ice there would require rather simple technology and could be done autonomously.  This would allow operation to continue without human presence in the planet.  Once liquid water is reached, it could be pumped to the surface and used as needed.  The biggest advantage is that ice, which would be a byproduct from mining, could be melted and used as water, too!

I pose the following question to the reader: It is clear that mining the icecaps would provide the resources needed to complete a mission of indefinite length on the surface of Mars, but what are the implications to the well-being of the astronauts? To the resources on Mars?

Resources (In-text included):

• http://www.space.com/scienceastronomy/080620-phoenix-ice-update.html
• http://www.nrel.gov/hydrogen/pdfs/40605.pdf
• http://www.wired.co.uk/news/archive/2010-10/08/ice-asteroids-common
• http://history.nasa.gov/SP-441/ch4.htm

Even if humans are able to make it to Mars there are still many unanswered questions. The most controversial issue that arises with a mission to Mars is the idea that it might have to be a one-way mission. The United States already possesses the beginnings of the needed technology to send man to Mars; we have already sent robots there. However, in the case of a manned mission, that is only half of the issue. Once an astronaut’s time on Mars is complete how are they supposed to get home? Since the actual spacecraft that carries man to Mars will need to be small, there is no viable way to launch from the surface of Mars with significant force to send it back to Earth. Even if it was decided to send a larger spacecraft to Mars in an attempt to allow for a launch off of the surface, the price would be astronomically large.

This issue has put a major damper on the whole prospect of manned Mars exploration. However, many scientists have argued that sending one man on a one-way mission to Mars would be the best solution. Critics of this idea state that this mission would indeed be a suicide mission and funding for such missions should be cut immediately. Many proponents of this idea argue that this would not be a suicide mission at all; it would be more a “lone-wolf” mission in which all of human civilization would be watching one man set foot on the moon. Still, many view this as an unacceptable mission.

In order to please all those opposed to this notion of a suicide mission, many have argued that the one-way mission of a single man would only be the beginning of many more to come. Many scenarios have been revealed that seems to solve many of the issues. One such scenario consists of sending a single man to Mars to begin setting up the beginnings of a colony. 26 month later (this is the window for launching Mars missions based on orbital physics) another spacecraft would be sent to Mars containing another individual to help with the construction of a biosphere. So the idea is that there will be only one person there for a short period of time. This pattern would continue until the technology existed to send multiple people per spacecraft to Mars.

Another scenario builds off of the above. In this situation, a man and a woman of reproductive age would be sent to Mars together. The idea is that they will create an “Adam and Eve” situation and create the beginnings of a civilization in Mars. Some years later, another “couple” will be sent to Mars to aide in the population of Mars.

Yet another scenario that combines the above is one in which many individuals would be sent to Mars in either single-manned missions or multiple-manned missions and create a population of roughly 150 people. This should allow for a significantly diverse gene pool and the population of Mars would grow quickly and diversely.

The ultimate goal in all of these situations is to find a way to populate Mars and create a livable colony on the Red Planet by using the least amount of money. By sending humans on a one-way mission, the need to launching from Mars is eliminated and instead of trying to cram enough supplies in a small ship to launch from Mars, we can provide the travelers with more supplies they might need on the Red Planet.

The simplest and most cost-efficient way of populating Mars is a series of one-way manned missions. It is up to each individual to determine if they believe these missions are suicide missions or “lone-wolf” exploration.

Sources:

http://www.universetoday.com/13037/a-one-way-one-person-mission-to-mars/

http://www.wired.co.uk/news/archive/2010-10/20/the-case-for-a-one-way-manned-mission-to-mars

http://www.huliq.com/8738/nasa-contemplates-manned-mission-mars-one-way

http://cosmiclog.msnbc.msn.com/_news/2010/10/18/5312576-going-to-mars-on-a-one-way-trip

http://www.mobilemag.com/2010/02/25/nasa-to-send-man-to-mars/

A manned mission to Mars is widely viewed as the present long-term goal of space exploration.  At their absolute closest, Earth and Mars are roughly 55-million kilometers apart.  Pointing a rocket at Mars and launching, however, isn’t the answer to getting there.  Due to the obvious desire to reduce the amount of time and fuel necessary to make the trip, a transfer orbit is the most realistic way to successfully get a spacecraft from the Earth to Mars.  A transfer orbit uses the orbital velocity of an object (usually a planet or moon), along with powered propulsion, to get from point A to B.  Because of the differences in the orbits of Earth and Mars, the optimal time to make a trip happens only once every 25 months.  Add to that the estimates that the voyage would take 6 months each way, and the challenges of sending a human crew to Mars become evident.

One way to shorten the time issue would be to change the propulsion method.  The main method used in the past and still today is chemical rockets.  They consume a large amount of fuel and are relatively slow when considering an interplanetary scale.  They’re what we’ve been using for decades to launch space vehicles, they’re very well tested, and they’re fairly safe when used correctly.  If a mission to Mars was going to be performed tomorrow, chemical propulsion is probably the method that would be used.

A possible alternate propulsion method would be the use of nuclear thermal rockets.  Anything with the word “nuclear” is often viewed skeptically, but in theory nuclear energy is remarkably powerful and efficient.  The spacecraft could use the nuclear power to produce electricity and to create artificial gravity.  There have been numerous cases of muscular atrophy and bone loss associated with astronauts who spend long periods of time in a microgravity environment.  Aside from the living conditions, the nuclear thermal rockets could propel the spaceship faster and for longer periods of time, accelerating the ship to Mars in roughly half the time of a traditional chemical rocket.  Nuclear propulsion would only kick in once in space, so the use of a chemical rocket would be required to launch the vehicle from the surface into orbit.  Because of this, no radiation is emitted into the Earth’s atmosphere.  The idea of using nuclear power in space exploration has been around for decades, but hasn’t ever really “taken off” due to the health and safety concerns of all of those involved.  With the relatively recent resurgence of interest in the human exploration of Mars, all the benefits of nuclear power have come back to scientists as a realistic propulsion possibility.

Ion engines are another propulsion method being considered to send a manned spacecraft to Mars.  Ion thrusters are used today in unmanned space vehicles because they are extremely efficient and can be run on very little fuel.  The downside is that they produce very little thrust.  The Ad Astra Rocket Company is developing an ion engine that is much more powerful.  In fact, they claim people could reach Mars in as little as 39 days, which is well inside the “comfortable” range of what humans have been exposed to.  Sending astronauts to Mars in a matter of weeks rather than months is obviously a benefit to this propulsion method, but still there is much testing and technology development that needs to be done before this method could be implemented into manned Mars exploration.

All things considered, nuclear power is the way to go.  The technology involved isn’t that far off.  There is an understanding of how to safely use nuclear power that is already in place today.  The United States Navy has a fleet of nuclear powered aircraft carriers that are said to operate more than 20 years without refueling.   The rocket technology isn’t here yet, but they aren’t as far off as the high-powered ion engines.  Ion engines are the long-range future of the manned exploration of Mars, but if a manned mission is going to be run in the next 10-20 years, this is the kind of high-speed, long-lasting, and efficient propulsion that’s going to be necessary to get the job done.

Sources:

http://www.universetoday.com/14841/how-long-does-it-take-to-get-to-mars/

http://www.wired.com/wired/archive/12.12/mars.html

http://www.space.com/scienceastronomy/solarsystem/nuclearmars_000521.html

http://www.newscientist.com/article/dn17476-ion-engine-could-one-day-power-39day-trips-to-mars.html?full=true

http://www.public.navy.mil/usff/nctamspac/Pages/AboutUs.aspx

In order for humans to travel to Mars successfully, extensive research and development must be put in to determine the best method of travel.  Numerous factors go into the decision on how to arrive at Mars.  Money for one is a huge factor, developing new methods of travel is expensive and some methods are too expensive, even for the government.  Next, the effect that the travel will have on human beings is being researched.  As one can imagine the trip to Mars will not going to be a short one.     The length of a direct route to mars will take about nine months.  There has not been an extensive amount of research conducted on humans in space for that long period of time.  The nine months is just to get there, there is another nine or so months to get back.  With the timing of launching and so forth the whole trip will take around two and half years.  The most feasible option is to take and indirect route to Mars through the International Space Station.  For the next decade or so the International Space Station will be frequently utilized by astronauts for all kinds of missions and research in space.[1]

The idea of the International Space Station is to create a sustainable living environment in outer space.  When humans launch a mars mission, stopping at the space station could provide some advantages.  First, the trip to mars is going to be long and very tough on the astronauts.  The space station could provide a “pit-stop” where the astronauts would benefit from a better living environment before continuing on to mars.  The space station has a greenhouse within it, the greenhouse has been used to produce oxygen, a vital resource.[2]  The astronauts could not only take the plants with them for oxygen in the future, but the oxygen tanks on-board could be refilled to maximum capacity.  Next, the shuttle could refuel and any repairs needed could be done at this time.  The stop at the space station would give NASA a chance to prepare even more for the trip, in terms of collecting new data and  inspecting the shuttle and instruments.  After stopping at the space station the shuttle heading to Mars is essentially fully prepared as it would be on Earth; with full tanks and prepared astronauts.  The stop at the space station not only makes the trip to mars safer, but it makes the trip more feasible in terms of the reality of extended space travel and the well-being of the astronauts.  In my opinion, man will never land on Mars unless a stop at the International Space Station is made.

Sources:

[1] http://www.spaceref.com/news/viewpr.html?pid=31927

[2] http://spaceflight.nasa.gov/station/