The Geohazards that Astronauts May Encounter on Mars

Never before in the history of humankind has it been possible to explore other planets and in the not so distant future it may become a reality. Advances in technology in the 1960s resulted in the first visit to the moon and these advances responsible for the proposed revisit to the moon in 2024 and a possible Martian exploration in the 2030s. The desire to visit other planets is strong and for Martian exploration to be successful, it is critical that we plan for every issue that could arise from visiting Mars. There has been much debate now for many years on whether to send humans to Mars despite the many challenges that are associated to planetary explorations. Is it feasible to send astronauts to Mars? Should we even contemplate extra-terrestrial space travel when faced with the uncertainties such as limited Oxygen levels, an atmosphere that is thin and made up 95% Carbon Dioxide, what will astronauts do in the event of disaster? These basic necessities are critical to human health and it will be an almighty challenge to ensure that these are plentiful on embarking on planetary expeditions.

Despite the dangers and the uncertainties surrounding our abilities to send people to Mars, the advances in technology in planetary science in the 21st century has enabled us to assume a successful mission to mars could be possible. Humans have always had the ability to adapt to their surrounding environment and on Mars it will be no different. In the following sections, I will explore the risk that these geohazards such as toxic soils and atmospheric composition and radiation have on astronauts. Indeed, for Martian expeditions to be successful planning for and try to mitigate the risk that these challenges pose associated with the Martian landscape will be critical. From this, I will explore the geohazards associated with the red planet such as geologic, atmospheric and radiation dangers that astronauts may encounter once on the Martian landscape. In researching these risks, the best outcome for a mission to Mars to be successful is to keep each problem to a minimum.

First of all, Mars differs greatly to Earth, the atmospheric composition, landscape and soil types are different from our home planet. Below is a table comparing, the various atmospheric and surface conditions on Mars and on earth. The conditions that I will focus on are related to atmosphere, pressure, temperature and radiation exposure. Taken from Horneck et al. 2011 paper on the critical issues with human missions to Mars, he describes the differences between the two terrestrial planets and highlights where humans could be at risk.

Toxic Soils

For astronauts to safely navigate their way around the Martian landscape, they have to wary of the soils that are on Mars and the dust as a product of soils. The soils on mars are composed of iron oxide, hydrogen peroxide and a toxic inorganic compound called perchlorate. Once heated they can become very explosive and they are a vigorous oxidizing agent. An experiment conducted and a paper written by Jennifer Wadsworth and Charles Cockell (2017) showed that bacterial cells exposed to this chemical lost its ability to function in a very short time frame. “Iron oxides and hydrogen peroxide, act in synergy with irradiated perchlorates to cause a 10.8-fold increase in cell death when compared to cells exposed to UV radiation after 60 seconds of exposure”. The effects of their experiment where profound. They used a vegetational cell called Bacillus subtilis and they were irradiated in the presence of magnesium perchlorate which have been found in Martian soils. This experiment was conducted under a radiation source being 254 nm that is within the range of radiation that Mars is exposed to (200-280). They focused on the viability of the cells when exposed to these levels of radiation.

Navigating over the Martian regolith is another important aspect to consider when transporting humans on Mars. The potential hazards associated with regolith include unstable movement or the instability to move in a timely manner across the Martian surface. Many of the possible challenges of Martian regolith include the following: degradation of mobility (potential breakdown of vehicles on the soft, bogy Martian surface), Instability of collision (possibility of vehicles colliding with boulders or other scientific equipment), mechanical failure (rock abrasion of tyres and wheels and the wear and tear of vehicles on Martian regolith) and rovers that move too slowly (in the event of solar particle events, the astronauts need to have fast transport to bring to shelter). The nature of the Martian landscape can be seen in figure 1 from Mars Curiosity Rover. These are the kinds on images that Nasa can study in order to make explorations on the surface as safe as possible. Analysis of the surface for stability and strength of the regolith can be determined by the images taken by the curiosity rover.

Analysing and investigating the components of the Martian soils is of critical importance to evaluate the risk and keep this problem to a minimum, thus enabling a possible safe mission to Mars.

Atmospheric hazards

As obvious as it may seem Mars is a lot different to earth. The gravity on Mars is 3/8 that of Earth (0.375m/s), its atmosphere is quite thin compared to earth (610 Pa) which is made up of CO2 (95.32%), Nitrogen (2.6%) and Argon (1.9%). Temperatures consist of -143°C (min) to 35°C (max). The climate is cold and dry which results in dust being distributed around the planet and it could prove to be a major challenge to future expeditions.

Dust storms is one of the most prolonged environmental hazards that exist on Mars. ”Large scale (regional or global) dust storms last for more than a single sol (Martian Day) or even weeks; thus, they significantly impact the atmospheric structure and circulation “. From these dust storms thick hazes can form up to 60km in altitude, covering the planet for possibly weeks on end. Dust has always been a problem for expedition rovers especially the curiosity rover that is currently roaming the Martian landscape. “NASA’s Spirit and Opportunity rovers- believed to have been produced by a passing dust devil- the accumulation of dust on the rover’s solar panels decreases their efficiency” (Calle et al. 2011). Furthermore, it has been found that the Martian dust can be toxic as chromium has been found in the past. “Data from the Pathfinder craft showed that chromium is present in Martian dust” (Calle et al. 2011). The issue of airborne dust on Mars is a major problem to future Martian exploration missions. This problem is ever present and finding a solution would be very difficult indeed. The only thing that can be done is to minimize this problem as best we can.

According to Charles Cockell (2001), Martian Polar Expeditions: Problems and Solutions, he puts forward a possible settlement that can be useful in the event dust storms for astronauts to take shelter. Even though this is a Martian polar expedition it can still be used in lower latitudes of Mars.

Space radiation is potentially the most critical problem to mitigate. The period in which humans are in space and on other planets increases their exposure to unknown particles that are in the Martian atmosphere. “The components of space radiation that are of concern are high-energy nuclei of heavier (high atomic number Z) elements- “HZE articles”, ”Short term consequences of radiation exposure is cell depletion of sensitive tissues such as bone marrow, skin”. “Long term exposure to expected levels of solar and galactic cosmic radiation results in an enhanced probability of cancer and possibly, changes in the cells of the brain”. (Schimmerling et al. 2003)

According to Jakel et al. (2004), he shows that protection from Galactic Cosmic Rays (GCR) and solar particle events in spacecrafts are inadequate at present and these would only increase astronauts exposure, “Typical spacecraft walls equivalent to of some g/cm3 aluminium not only are inadequate for shielding from GCR, but even increase the dose for astronauts inside the vehicle”, “Increases of 10% in dose were found”. Previously there has only been as mall number of humans in space so, we don’t have a lot of experience when dealing with GCR or solar particle events which would impact to the preparation for future space missions. “As only 24 human beings have ventured beyond the protective magnetosphere of Earth for a maximum 12 days (Apollo 17) and none have encountered a significant SPE during these missions” Hu et al. (2019). This paper (Jakel et al.2004) also presents some measures to try to minimize the problem as much as possible. It puts forward, “limit the time of exposure and the duration by various strategies, such as selecting older crew members, avoiding extravehicular activity (EVA) during impeding Solar particle events”, and shielding against exposure, “computational tools have been developed to calculate how incident radiation is modified at any depth in materials” This is a mitigating method that is used presently to estimating spacecraft shielding but obviously this needs to be altered to suit astronauts on the surface.

The three major geohazards on Mars that astronauts may encounter are terrestrial (regolith stability and toxic soils) Atmospheric (dust storms, lack of oxygen and solar winds ) and radiation ( GCRs and SPEs). Each have their consequences which could prevent successful exploration of Mars. The issue of toxic soils is of major importance if humans are to navigate on the Martian landscape without falling victim to its potentially fatal components such as perchlorates. The atmosphere on the red planet is very thin which could make it very challenging for astronauts. Dangerous conditions such as dust storms can cover the planet for weeks and possibly months resulting in no sunlight getting to the surface, solar winds may make explorations close to impossible due to its unpredictability and unknown intensity. Finally, radiation the biggest challenge of all that is ever present on mars. The constant danger of ionizing radiation could prove to be unavoidable and the need for major protection could make mission to mars impossible.

From Charles Cockell’s paper as stated above, it is possible for missions to mars to be successful. Settlements such as the ball tent igloo as described in his paper and with further modifications such as radiation protection incorporated into the design, mitigating hazardous conditions most notably radiation could make Mars a little less inhospitable.

Conclusion

The debate to whether sending astronauts to Mars will rage on in the coming decades. It is therefore critical that geohazards like these stated above are acknowledged, planned for and kept to a minimum. There is plenty of research on this topic which explores both the dangers of extra-terrestrial exploration and the possible strategies that resolve these hazards but there is some way to go to a potentially successful Martian exploration mission. It is important to remember that humans have overcame obstacles before and in the case of sending humans to Mars anything is possible with the advances in them technology that have and have yet to occur.

Reference list

• Horneck G. et al., (2011). Critical issues in connection with human missions to Mars: Protection of and from the Martian Environment. Advances in Space Research. Vol., 31 Issue 1., pp., 87-95.
• Wadsworth J. & Cockell C. S. et al., (2017). Perchlorates on Mars enhance the bacteriocidal effects of UV light. Nature. Vol. 7, Iss., 4662 pp., 1-8.
• Guha K. B. et al., (2019). Analysing some Martian atmospheric characteristics associated with a dust storm over the Lunae Planum region during October 2014. Icarus. Vol. 319., pp., 293-307
• Calle C.I. et al. (2011). Active dust control and mitigation technology for lunar and Martian exploration. Acta Atronautica. Vol. 67., pp., 1082-1088.
• Schimmerling W. et al. (2003). Radiation Risk and human space exploration. Advances in Space Research. Vol. 31., Iss., 1. pp., 27-34.
• Jäkel O. (2004). Radiation hazard during manned mission to Mars. Zeitschrift für Medizinische Physik. Vol.,14. Iss., 4. pp., 267-272.
• Hu S. et al. (2019). Acute Radiation Risk Assessment and Mitigation Strategies in Near Future Exploration Spaceflights. Life Sciences in Space Research.