Obstacles and Solutions for Human Travel and Exploration of Mars Man is not destined to stand idle in the face of new frontiers and undiscovered fortunes. Since the beginning of time, man has risked nothing short of his own life to step beyond dreams and achieve the reality of the new and undiscovered. With the need to find these new corners of the universe, new technologies must be achieved giving man not only the abilities to overcome the impossible but the opportunity to better understand man himself. The conquest of Mars is a necessary step to exponentially leap man’s knowledge into new realms of understanding. The conquest of Mars is no longer an option but a necessity. I have been tasked today to present to my audience the obstacles and solutions associated with human interplanetary travel with respect to Mars. While many current fuel and propulsions systems are purely hypothetical, the idea to propel is basically the same. The principle is based on Newton’s Third Law of Motion: For every action, there is an equal and opposite reaction. As propellant is expelled from the spacecraft, a reactionary force is acted upon the spacecraft creating movement. This can be done in many forms including chemical propellant, electricity, nuclear, and solar sails. Chemical propulsion systems are the current propulsion systems of choice in the current world’s space programs. Chemical propulsion systems contain a fuel source and oxidizing agent that are mixed and burned in a combustion chamber. As explained in Living Off the Land in Space, “The energy is released as new chemical bonds are formed in the ‘burning’ process. Channeling the energetic reaction products outward from the vehicle using a directional nozzle produces thrust (Matloff, Johnson, and Bangs 29-40).” Chemical propulsions continue to dominate the current preferred method of space travel and deployment due to a proven track record in predictability and safety. Aggressive interplanetary space travel will place stress on current trends of chemical propulsion systems due to cost, time, and payload limitations. While many different sources of fuel can be used as propellant for chemical propulsion systems, these fuels are subject to increasing costs. Adding to the cost of fuel, large amounts of fuel are required to move relatively small payloads further straining the limitations of current chemical propellant systems. Giant multistage rockets are packed almost completely with propellant. The passenger and cargo space accounts for no more than one-thousandth of their volume (Vasilyev and Stanyukovich 94). Nuclear propulsion systems have become the most promising of future technologies to propel man to Mars. Nuclear propulsions work similarly to chemical propulsion systems by using liquid hydrogen stored in hydrogen tanks that become superheated by an onboard nuclear reactor. The superheated hydrogen is expelled in a similar fashion as the chemical propellant in chemical propulsion systems. According to scientist John Pike,
“Nuclear thermal propulsion has been identified as offering a number of advantages over non-nuclear systems. Propulsive capture at Mars eliminates the need for aerobraking, which faces technical risks and operational uncertainties, though nuclear propulsion can benefit from incorporation of aerobraking if it is available. In addition, nuclear thermal propulsion can reduce total trip times by 50 to 100 days relative to chemical + aerobrake architectures with the same initial mass in low-Earth orbit, and as a result is less sensitive to launch window constraints (Pike).”
Limitations for using nuclear propulsion systems include possible hazards of radioactive emissions in Earth’s orbit from catastrophic explosions and crashes. Catastrophes of this nature could possibly expose the world to high levels of unnatural radiation. Many new technologies being looked at for replacing current interplanetary propulsion systems like the use of solar sails and solar energy. Solar sails propulsion is the use of large reflective sails that reflect light. This reflected light exerts a pressure on the surface of the sails. This technology is currently used by geosynchronous satellites for minimal fuel saving repositioning but cannot be used for overcoming large gravitational pulls. Solar energy is an abundant energy resource in space but has known limitations of efficiency. An example of an inefficiency is noted by Jim Haldenwang in The Human Exploration of Mars as he states, “Unfortunately, the power-to-weight ratio of solar cells is only 1/40 that of lightweight nuclear reactors (Haldenwang).” Even as technology promises to lower operating costs associated with interplanetary travel, any trip to Mars promises to be expensive. NASA studies currently estimates that human and robotic missions to the moon and Mars would total roughly 120 billion dollars by year 2020 with NASA’s current annual budget around 15 billion dollars. Costs in the infancy of Mars travel are going to be high. I would even suggest that any estimated budget would soon be over budget once Mars projects began to come to fruition; however, costs now should not scare taxpayers and governments from supporting Mars exploration. Investment in any interplanetary space program to remote locations like Mars can yield exposure to finite and rare materials on Earth like iron, gold, and possibly even basic raw life supporting necessities like water. With new technologies that will need to be developed, it should not be unreasonable that some of these technological enhancements will filter into our society as they have in the past. These technologies can not only finance current and future space programs but increase the quality of life for members of our society. Pending propulsion methods adopted for the travel to Mars, current scientists are estimating a six to nine month one-way trip using conventional chemical propulsion systems. These time estimates are destined to shorten as Mars missions become second nature and technological developments come into development. While the enormous quantity of time spent traveling to Mars can become a quality of life issue for travelers, the true issue of time is radiation. Three major concerns with respect to radiation is time, distance, and shielding. Minimizing a traveler’s time exposed to ionizing radiation reduces the effect of radiation on the human body. Decreasing the travel time from Earth to Mars decreases the amount of radiation travelers are exposed to ionizing radiation. Reducing exposure reduces the traveler’s acute dose received. Distance plays a very important role in minimizing a traveler’s exposure. Distance to radiation can be maximized by choosing flight windows and travel routes that pose the least risk to personnel. Solar events are known sources for large amounts of solar radiation and can be predicted based on the Earth’s location relative to the Sun and whether or not the Sun is experiencing large amount of solar flare activity. Mars interplanetary vehicles will have to maximize shielding to help prevent exposure to crews. While flight paths and solar weather predictions can reduce the exposure caused by solar radiation, there is still the fear of galactic cosmic radiation. But shielding a spacecraft requires mass, and the mass of shielding that can practically be launched on a spaceship will only reduce galactic cosmic radiation by 20% to 30% (Tenenbaum). It is debatable whether or not man is ready to begin the daunting task of sending manned missions to Mars. With current chemical propulsion systems the preferred technology of interplanetary travel, we find large restrictions in the form of deliverable payload efficiency, costs, and time. Large start up costs for more efficient propulsion systems will afford space programs with safer and more efficient interplanetary vehicles. This increased efficiency will grow into huge advantages by reducing time spent in travel, reducing crews risk to solar and cosmic radiation, and allow us to reach depths of space that were once unattainable. The world should be made aware that the risks in any new endeavor will inevitably be costly. We can expect that there will be lives lost, projects that will not deliver, and large monetary obligations. As with the early explorers, the risks will pay off exponentially more than what we can invest into it. Man should look beyond the sport of who can get to Mars first, but look to possibilities Mars has to offer. In a gamble that the world we live in now will forever be habitable, we are slow to venture beyond it. With increasing populations, pollution, and the questionable state of the Earth’s health, costs, technology, and the hazards of going to Mars should not be the fear that prevents us from trying.

Works Cited

Pike, John. “Space Exploration Initiative.” Federation of American Scientists. Circa 1992
< http://www.fas.org/nuke/space/c07sei_1.htm>.

Haldenwang, Jim. “The Human Exploration of Mars.” Jim's Science Page. revised 05 Jan 2006
< http://members.cox.net/jhaldenwang/mars.htm>.
Matloff, Gregory, Les Johnson, and C. Bangs. Living Off the Land in Space. New York: Springer, 2007
Tenenbaum, David. “How Safe is Travel to Mars.” Mars Daily. 24 Oct 2006 .
Vasilyev, Mikhail, and Kirill Stanyukovich. Matter and Man. The Minerva Group, Inc., 2000