Manned Voyages to Mars Must Overcome Big Challenges
By Gary Deel, Ph.D., JD
Faculty Director, School of Business, American Military University
For centuries man has dreamed of traveling to Mars. Unfortunately, sending humans to the “red planet” is an undertaking rife with obstacles, and it will take more than a vivid imagination to solve them.
Challenges of a manned Mars mission include, but are not limited to, deterioration of the astronauts’ health due to long-term exposure to microgravity environments; damage to the spacecraft and its crew caused by galactic cosmic radiation; and stresses on the human psyche from isolation and confinement.
Challenge 1: Microgravity
One major concern for astronauts headed to Mars will be the long-term exposure to microgravity and the anticipated aftereffects. We know from careful studies of astronauts returning from long stays in space that their bodies deteriorate over time due to a lack of bone and muscle use. In the near-weightlessness of space, the human body is not required to maintain a resistance against gravity as is constantly demanded here on Earth.
As a result, the bones that support the human frame tend to lose mass, and the muscles that manipulate the bones atrophy. Even the heart, which is regularly pumping blood through arteries and veins against the force of gravity, does not have to work nearly as hard in space. Consequently, in a microgravity environment what we do not use, we lose.
In the same way that people who suffer from quadriplegia lose bone and muscle mass in their unused arms and legs, in space our bodies begin to metabolize unneeded mass. The record for the longest uninterrupted visit to space is held by Russian cosmonaut Valeri Polyakov, who stayed aboard the Mir space station for 437 days in 1994-1995. Because of orbital dynamics, a manned mission to Mars and back would likely take at least two years, nearly double that of Polyakov’s record space trip.
Fortunately, there are some things that can be done to mitigate health concerns associated with microgravity. The first would be for the astronauts to maintain a strict daily regimen of intense exercise using resistance workout equipment. However, while this can help abate bone and muscle loss, it does not completely solve the problem.
An artificial gravity needs to be created aboard the spacecraft to completely avoid harm from microgravity. This could be done relatively simply through a rotating ship design, which would use centrifugal and centripetal forces to simulate gravity. If aerospace engineers designed crew cabins and workspaces in the shape of a spinning ring within the hull, crew members would feel a force propelling them outward from the rotation and they would feel an opposing force from the inside of the ring on which they would “stand.”
These are the same forces you felt as a child when you locked hands with a friend and spun around in circles. If the ring were built to the correct diameter and with the correct rate of rotation, it could perfectly simulate the 1G gravity felt on Earth, and the astronauts would feel the same resistive forces as if they were at home.
Challenge 2: Galactic Cosmic Radiation (GCR)
There are two primary sources of cosmic radiation in our solar system: the Sun and the center of the Milky Way galaxy. Both, unfortunately, can be harmful to spacecraft and humans aboard them, so both sources of cosmic radiation need to be considered in planning long-duration space voyages.
Even in Earth orbit, astronauts brave these dangers, but the risks are significantly less near our home planet. That is because the Earth generates a robust magnetic field that repels much of the cosmic radiation that comes our way. However, outside Earth’s magnetic field the danger is much greater. Radiation can permeate spacecraft hulls and damage electronic systems, as well as catalyze mutations within organic DNA that can ultimately lead to cancers and other maladies. Particularly high-energy particles, called cosmic rays, can carry the kinetic energy of bullets fired from a gun. Under the right circumstances these particles could potentially puncture a spacecraft. So a transit between Earth and Mars would be fraught with danger. And the risk would not abate once Mars was reached because, unfortunately, the planet does not have a substantial magnetic field like the Earth has. So a spacecraft orbiting Mars would be just as vulnerable to high-energy particles as if it were in deep space.
To make matters worse, spacecraft shielding and insulation do not do much to mitigate this kind of threat because cosmic radiation can pack a great deal of energy. One possible solution that was proposed long ago to mitigate this risk is an artificial magnetic field generator that could be installed on a spacecraft. It would create an electromagnetic buffer between the ship and the outside space environment. However, despite our best efforts, we have yet to engineer a generator powerful enough to provide adequate protection and light enough to launch into space.
The only other way to possibly mitigate the risks from cosmic radiation would be to time the launch when radiation from the Sun would be minimized. Solar activity waxes and wanes in 11-year cycles called solar mins and solar maxes. Normally, solar mins are periods of lower radiation emissions. But the Sun’s magnetic field, which works to trap a lot of its own radiation, is also weaker during a solar min.
By contrast, during solar maxes the radiation output is higher, but the Sun’s magnetic field is stronger. So it would seem to be a hopeless problem of “six of one and half a dozen of the other.” However, in recent cycles the Sun’s solar maxes have actually been milder in terms of radiation output than in past decades. So on balance, a near future solar max might offer a safer opportunity for a crewed Mars transit.
Challenge 3: Psychological Fragility
The psychological fragility among astronauts making such a long journey is another challenge to consider. As noted, the longest stay in space has been a little more than a year. So opportunities for observational research on the psychological effects of long-term space flight have been limited. Frankly, we really do not yet know what to expect from truly lengthy space flights.
Simulated experiments of human isolation on Earth have yielded mixed results. In some of the worst cases, such as the Biosphere 2 experiments of the 1990s, teams of humans confined to an artificial habitat fell victim to tension, anxiety and interpersonal conflict, which ultimately led to the collapse of the experiments.
However, other simulations conducted by NASA suggest that peaceful cooperation and stability for long periods of isolation are at least possible. There are many variables to consider in these situations, but stress will be ever-present in such confined environments. And it could certainly compromise a mission to Mars.
The first step to ensuring psychological stability in a crew to Mars is to use careful screening and matching tools so that crewmates are compatible and their personalities will not clash and cause tension. Second, the spacecraft environment and crews’ work schedules should be engineered to minimize stress. Entertainment and leisure activities should always be available so that the crew has a means of escaping the feelings of confinement and isolation. For example, in some of the NASA simulations, test subjects were permitted to use virtual reality technologies for some “alone” time when they needed to destress.
Also, communication back home should also be available whenever crew members feel the need to check in with family or friends. Delays in communication between Earth and the spacecraft could take as long as 25 minutes, depending on the distance separating them. But astronauts could still transmit messages home as often as they like and await replies.
Last, it might be wise for these missions to consider having a psychologist accompany the voyage, so if a crew member needed to talk about his or her psychological stress, a professional would be available. Of course, this raises the question of who the psychologist would consult if he or she needed someone to talk to…perhaps two psychologists should go? This is a partially tongue-in-cheek suggestion, but it illustrates how important thoughtful planning will be to a lengthy mission like this.
There are many challenges that humans will face on the first missions to Mars. But none of these challenges are insurmountable. If we support the work of our scientists, engineers and innovators as they overcome these obstacles, there is no reason why manned missions to Mars should not end in success.
About the Author
Dr. Gary Deel is a Faculty Director in the School of Business at American Military University. He holds a JD in Law and a Ph.D. in hospitality/business management. Gary also holds a bachelor’s degree in space studies and is an avid student of the astronomical sciences.