Humanity to Mars

By | 21/10/2023


Getting to Mars

The race is on – within 20 years humanity will have established itself on the lunar surface, with at least 1 permanent settlement, likely more as the Chinese go it alone, but the plans also involve human boots on the surface of Mars within around 15 years, with some advocating 2033 as a possible date because of the favourable positions of Earth and Mars reducing a round trip to as little as 20 months rather than the normal 34-37 months.

I fully support humanity expanding off the planet and into the solar system, I wish that humanity had come together in the early 1970’s to establish bases and a permanent presence on the lunar surface instead to retreating back to low Earth orbit.

The plans held by those players trying to get to Mars are putting the lives of the astronauts and the future of humanity exploring Mars in significant jeopardy, based on what is publicly known.

We know the Martian environment is hostile to life on Earth, a damaged suit would almost certainly mean death, and the risks on Mars are significantly higher than on the lunar surface. On the Moon there was, and still is a risk, radiation levels are very high, an astronaut could theoretically puncture their suit – which would stand a high chance of being fatal depending on severity, but on Mars, these risk rise dramatically. Radiation levels are lower on the surface than on the Moon, but significantly higher than Earth, thus radiation exposure is a significant, but a manageable threat, the real danger comes from gravity,

The lunar gravity is about 16% Earth’s, but Mars is just over 37%, more than twice the lunar gravity and thus as astronaut falling will impact the surface with about 5 times the kinetic energy than on the surface of the Moon, we know from lander and rover images that the surface is strewn with rocks of all sizes, many would present a significant hazard to an astronaut.

The surface of Mars is strewn with rocks of all sizes

At present the publicly available details call for the use of systems not too dissimilar to those used during the lunar landings half a century ago, with astronauts surviving on the surface for perhaps as long as 24 months without recourse to assistance from Earth if anything goes wrong.

This makes no logical sense, if there is a problem on the surface, such as a global dust storm, or any problem which makes getting back to Earth an absolute requirement then launching from the surface to come directly back to Earth has some serious issues.

When launched within the proper launch window, the spacecraft will arrive in the planet’s orbit just as the planet arrives at that same place. At this point, the spacecraft is positioned for either going into orbit about the planet or landing on the planet.

If a spacecraft is launched too early or too late, it will arrive in the planet’s orbit when the planet is not there.

Launching is crucial, optimal launch windows do not happen every day, and this is important no matter which body you are launching from, it is vitally important orbital calculations are done correctly before leaving the orbit of the planet you are leaving, failure to do correct calculations to ensure the correct orbital velocity, engine burn length and fuel requirements will have fatal consequences.

Below we have an ideal launch window list for getting from Earth to Mars between 2020 and 2029, you will note that the duration of flight time varies considerably as does the required velocity to achieve a successful orbital injection.

What this means is that any humans that land on the surface of Mars will need to have everything we could possibly think of to cover any eventualities in the 16-28 months they may be on the surface – that brings other questions that need to be looked at.

  1. How many crew is the minimum safe limit?
  2. How many crew is the maximum practicable limit?
  3. How many crew is the maximum safe limit?
  4. Will multiple crewed craft be sent at different times to spread the risk and increase compliment?
  5. What will the crew make up be?
  6. What facilities will be sent ahead of the crew arrival?
  7. Will facilities and stores be sent after they depart Earth to further support the mission?
  8. Will any facilities or resources, human or material, be left in Martian orbit to cover unforeseen eventualities?
  9. How will those on the surface navigate – given a compass will be useless and no really accurate maps exist at a scale that would be useful to navigate the surface safely.
  10. What are the parameters that would call for a mission abort and how would it be managed with risks mitigated?
    1. After launch but in Earth orbit
    2. After they have left Earth orbit but are less than 50% the way to Mars
    3. After they have achieved Martian orbit, but have not yet reached the surface
    4. After they land on the surface
    5. After they leave the surface and or in Martian orbit – but not yet in the ideal transition window?

Lets address these points.

  1. How many crew is the minimum safe number?.
    • I would suggest that the minimum safe limit will be determined by the mission parameters and several practical limits
      • Doctor – absolute requirement.
      • Engineer – they would need the skills to undertake repairs in the event of fault or damage
      • Geologist – pretty clear why
      • Biologist – pretty clear why
    • That would mean the minimum would be 2 as they could all be trained to undertake multiple roles – many geologists have engineering skills and a biologist/doctor can easily be cross trained, however, if anything happens to either one you need an alternate – especially for doctor and engineer – thus, in reality the absolute minimum would need to be 4 crew to ensure each critical task was covered in the event of an emergency.
  2. How many Crew is the maximum practicable limit?
    • This is dependent on the design of the crewed vessel that is used to leave Earth orbit and travel to Mars and you must factor in the length of time on the surface and the mission parameters – in theory, there is no practical limit beyond what the engineering allows, but bear in mind that you need to carry sufficient food for this crew too, there are no McDonald’s on Mars just yet (give a few years!)
  3. How many crew is a practical safe limit?
    • Here it is a matter of taking into account the restictions, needs of the mission and facilities and then determining what would be the maximum number of people we would be willing to place on Mars, and if that outpost was to be permanently manned – if the latter, then you could have crews overlap in time to keep a permanent presence and this would fundamentally change how you decide this limit.
  4. Will multiple crewed craft be sent at different times to spread the risk and increase compliment?
    • This will likely not happen initially, but I believe it would be a sensible way forward to both sustain crews on the surface, but also to ensure that you cannot lose all the assets in one disaster – and sadly that is very likely to happen at some point. Between November and December 2026 there are several launch windows that allow multiple vessels to be launched and leave Earth orbit, but arrive at Mars close together in time – this would spread the risk and ensure that we would make it to Mars. The big question, is will they survive and will they ever return to Earth?
  5. What will the crew make up be?
    • As with earlier points, this will be impacted by the mission parameters, however, I can see no reason why the following crew makeup would not be a serious consideration as a minimum.
      1. Mission Commander – Doctor/Biologist
      2. Mission Specialist 1 – Geologist / Engineer
      3. Mission Specialist 2 – Biologist / Paramedic / Communications
      4. Mission Specialist 3 – Engineer / Communications / back-up pilot
      5. Mission Specialist 4 – Biologist / Environmental specialist / Paramedic
      6. Mission Specialist 5 – Physicist / Engineer / Communications
  6. What facilities will be sent ahead of the crew arrival?
    • Here we get controversial, clearly food, habitats, engineering, communications and similar important facilities need to be on the surface before the crew arrive, equally, they will require power generation so careful consideration needs to be given to this – we know that Solar panels are covered in dust very easily, this has ended many missions to the red planet, but humans can clean them so this is less of an issue here, however, we need out of the box thinking here and provide the explorers with a measn to get about – so electric vehicles would be a great idea, these can be solar charged and would increase the mission scope, but they need to be able to navigate.
  7. Will facilities and stores be sent after they depart Earth to further support the mission?
    • Absolutely, we cannot relay on nothing untoward happening, either on route to Mars, or post arrival/landing. Mars has been the deathknell for as many missions as have been successful. Errors have been made with orbital insertion that meant missions missed the planet, or burnt up in the atmosphere – Mars is a hard planet to succesfully land on and a harsh environment to operate in, we must ensure that supply missions are plannned and slotted in even before any humans are launched form the surface of Earth – if it turns out we do not need them this time, they can be used for future missions.
  8. Will any facilities or resources, human or material, be left in Martian orbit to cover unforeseen eventualities?
    • Failure to do this would be a critical mistake, we cannot know or presume to predict every potential eventuality, if a crew on the surface suddenly found themselves unable to launch off the surface we must ensure that, as in 7 above, they have the resources and facilities to survive whilst they work the problem, or a solution is sent from Earth.
  9. How will those on the surface navigate – given a compass will be useless and no really accurate maps exist at a scale that would be useful to navigate the surface safely.
    • This is a serious and vital subject that requires serious consideration, this will be looked at in Navigation below.
  10. What are the parameters that would call for a mission abort and how would it be managed with risks mitigated?
    1. After launch but in Earth orbit
      • It is clear that any event that would cause any restriction on the mission success should require an immediate abort with the crew being returned to the surface at the earliest safe opportunity.
    2. After they have left Earth orbit but are less than 50% the way to Mars
      • This is a difficult one to cal, but if there are any issues, health related or vehicle related, that would put the mission success into question, the crew should be ordered to immediately burn and return to Earth Orbit – but when and how this call would be made would have to depend on the relative positions of the planets, the vessel and the exact nature of the issue with the mission.
    3. After they have achieved Martian orbit, but have not yet reached the surface
      • If the crew could not safely land on the surface, or they could not afely return from the surface, then they would need to abort the mission at this stage, staying in Martian orbit until such time as the planets were suitably aligned to allow for the safe return to Earth.
    4. After they land on the surface
      • Here things get tricky, the exact nature of the issue would be a determining factor on whether the mission should be partly or fully aborted, possibly even extended beyond the mission design length. If the issue would mean they could not leave the surface then clearly extending of the surface mission length would have no other option. Things are difficult here because the planets are unlikely to be within the window that would allow a safe return to Earth, and that raises a lot of further issues that must be addressed -and that is far beyond the scope of this article.
    5. After they leave the surface and or in Martian orbit – but not yet in the ideal transition window?
      • Depending on the issue faced, they may have the option to return to the surface of Mars if the transition to an Earth interception orbit cannot be successfully achieved or executed – such as damage that would mean they could not safely return to Earth successfully.

Lets address the elephant in the room regarding navigating around Mars. The highest resolution mapping for the surface of Mars has been put together from more than 11o,ooo individual hi-res images taken by the Mars Reconaisance Orbitor (MRO) over more than a decade of orbiting the red planet and it can be found here. You can navigate this amazing work, locate features on the planet and even see where all the missions have landed – or crashed – over the last 60 years, the entire map is 5.7 Tera pixels in size and maps down to 5m (16.4ft) – but this is an orbital view – not very good for navigation across the surface in a vehicle or on foot – especially as the map will clearly not fit on a portable device.
If you visit this amazing resource and navigate around, you will notice it has navigation references in the top left corner which are based on the prime meridian of Mars. This was established initially, in around 1830-1832 by the German astronomers W. Beer and J.H.Modler, they based this on the small circular feature on the surface they used to calculate the rotation period of Mars, then in 1877, when Giovanni Schiaparelli drew his famous map of Mars, he used this same feature as the zero point for longitude, subsequently to this, the French astronomer, Camille Flammarion called this feature Sinus Meridiani (Middle Bay). In the 20th century, Merton Davies, who worked at the Rand Corporation, designated the 500m wide (0.3mile) crater, located in a wider crater, Airy, located, itself,  within the Sinus Meridiani as a reference point, this smaller crater was called Airy 0. This became the reference point that is now used for the Mars reference system – but there are serious drawbacks to this if you are on the surface of the planet.

  1. There is no global magnetic field on Mars that would allow the use of a calibrated compass for navigation between points on the surface.
  2. The perspective we have from orbit will be wholly different from that at the surface, even a 5m resolution is no good for accurate navigation by explorers.
  3. Getting lost on Mars would be fatal and you cannot call for help to rescue you except from members of your team, but if you do not know where you are, how are they to find you?
  4. An individual on foot, or in an SUV sized vehicle would be almost, if not, impossible to spot from orbit.

So, how do we overcome this issue? Clearly, unlike Earth, we cannot send  people out to map areas we think will be interesting, as old explorers did, because there is the problem of surviving – they require Oxygen to breath, food to eat, water to drink, power to keep warm as well as other resources – but we cannot map the surface accurately from space either, we need a resolution of around 0.5m to be truly effective, but even this has challenges.

Of course, people could be taught to navigate by the stars, as our ancesters once did, and in daylight we can sort of navigate by the position of the Sun, but as already noted, without a compass, there is a lot of error involved in that type of navigation without a lot of training. However, we have the answer here on Earth, the Global Positioning System satellite constellation, these provide accurate information that allows the precise location of an object or a person to be located on the surface of Earth. Adapted, and combined with hi speed communications technology, such as smart phones, these could provide the navigational accuracy required to explore the surface and allow real time telemetry to both track and communicate with team members on the surface.

It would make sense to put a small constellation of satellites in Martian orbit that are a mixture of the GPS satellites and the SpaceX Starlink system, effectively returning to the core of the original GPS system which was the Timing and Data Relay Satellites (TDRS). A constellation of 48 – 60 such satellites would allow real time, over the horizon communication and navigation, a combination of a satellite and a smart phone could then be used to both communicate and navigate, much as we do on Earth. This constellation could be sent to Mars far sooner than any manned crew with the new Starship system being used to deliver them in one flight – assuming Starship works, although if if there are some failures it is safe to say that Elon Musk will not give up and the system will eventually be made to work, just as he did with all other launch systems developed by the SpaceX.

Movement on the Surface

Getting around on Mars is fraught with difficulty, radiation levels at the surface present a significant hazard to life from Earth, and the lack of air pressure requires any humans on the surface to be wearing a pressurised suit, not as cumbersome as an Apollo era suit, but it would need to be reasonably substantial to give realistic protection from the hard radiation at the surface, protection from puncturing should the wearer fall over or rub against a rock, flexible enough to be practicable and strong enough to maintain a pressure in the suit of at least 0.70 Bar/atmospheres, equivilent to some 3000m above the mean sea level on Earth.

Studies by the rovers on Mars indicate a variable radiation exposure rate that varies from 153mSv/year to 274mSv/year, depening on the activive state of the Sun. The average natural radiation exposure on the surface of Earth is estimated to be around 6.2mSv/year, although in the city of Ramsar in Iran, natural radiation levels average some 260mSv/year, and the local population seem to be no worse for this higher exposure. Clearly, humans on the surface require protection from radiation exposure on the surface when moving around – no protection would be foolhardy – thus we require protection from this natural background radiation, and a good potential source of that protection may be in Carbon Fibre materials.

Due to their resistance to radiation, high specific strengths, low densities, lightweight, rigidity, good fatigue characteristics, resistance to creep properties and the ability to mold into multiple shapes and complex, fiber reinforced polymer composites that are being increasingly employed in the aerospace industry and even in nuclear reactors. Carbon Fibres exhibit a crystalline graphite base with a non-polar surface and chemical inertness due to the high temperature carbonisation/graphitisation step in the manufacturing process. Researchers have found that epoxy resin has excellent mechanical strength and heat stability as a new class of matrix material for advanced carbon fiber reinforced epoxy resin matrix composites (CF/EP)[1][2]. Epoxy resins exhibit good thermal stability and strong radiation resistance, but when exposed to high energy gamma rays, they degrade rapidly and mechanical properties are drastically reduced. In addition, CF/EP exhibit reduced physical-chemical properties when exposed to high-energy gamma rays, especially resin degradation and interface area debonding[3][4] , which are some of the disadvantages of fibers and resin. Clearly, Carbon Fibre/Epoxy materials may be a way forward for short exposure suits on the surface of Mars – but there are other materials which may provide better protection whilst giving the same flexibility and ability to mould into suit sections.

Radiation is a very real issue, and cannot be ignored, but neither should it be overplayed – it is still significantly lower than the hard radiation encountered in orbit or on the journey to Mars if precautions are not taken. The radiation issue is more of a concern for habitats where crew would be expected to operate in a “shirt sleeve” environment.

Habitates on Mars will either need to be naturally protected from radiation exposure, underground, but initially in Lava tubes that are significantly larger than on Earth due to the difference in gravity, or they will need to be “hardened” against radiation exposure.

General habitation and office habitates should be deep within lava tubes or under ground caves, these have more stable environments and provide natural radiation defence, the only habitate we may wish to have at the surface would be those that require a minimal suit and their outer skin is hardened against radiation, these could be waystations between the surface and the subsurface habitats. Radiation defence has to be one of the highest priority items on the list of safety concerns when humans travel to Mars.

Unlike the Lunar surface or space the suits used to move aboout the surfce of Mars do not need to be of a design that significantly restricts movement, thus walking, bending, twisting at the torso and using tools should be far less of a problem – the suits will need to be able to maintain safe body temperatures, whilst this is not the harsh environment found in orbit or on the Lunar surface, the average temperature on Mars is still significantly lower than Earth, the average surface temperature on Mars is -62.5°C (-81°F), but depending on the time of year and your location, these temperatures can vary from winter polar temperatures of -140°C (-220°F) to an an equatorial summer temperature of +21°C (70°F).

Temperature Records for Gale Crater (2012-2015)

Maximum °C 661071420197788
Maximum °F434334304557686645454646
Average High °C −7−20−23−20−402114−1−3
Average High °F-19-4-9-4-25-32-36-34-34-39-30-27
Record Low °C −95−127−114−97−98−125−84−80−78−78−83−110
Record Low °F−139-197-173-143-144-193-119-112-108-109-117-166

Keeping comfortable is crucial – suits would require a system similar to those used by EVA or Lunar suits that are able to moderate the internal suit temperature, the body of the crew member would generate heat, thus this heat would need to be removed to prevent them overheating – at the same time the suit systems would need to take into account the current external temperature – if this system were to fail, hyperthermia for even the fittest crew member would be a matter of minutes away at the wrong time of year, but an ever present danger on all but the hottest days.

Humans expel CO2 as part of their natural respiration process, but there is also a lot of Oxygen in our breath, in fact, only 4-5% of the gas we breath out is CO2, the majority can be reused via a “rebreather” to recover Oxygen and Nitrogen, whilst we may be able to develop a system to remove O2 from CO2 and utilise that, at worst, we could expel the CO2, from the suit respiratory system, directly to the Martian atmosphere, which is already some 96% CO2. Resusing as much of the air we breath as technology allows makes sense.

The human body is a heat engine, it converts chemical energy stored in the food we consume, or fat we have stored in our bodies, into metabolism to power our brains, organs and muscles, and a by product of all these processes is thermal energy – heat. The harder the body exercises, the greater the heat production and thus the greater need to reject this heat to prevent the body overheating, which can be fatal. Our bodies reject this heat to the environment via a combination of radiation, convection and evaporation

The average human body generates between 60W and 600W (1050W in extremes) per hour (on Earth) depending on the activity, with the average being variously taken as 110-120w/hr – that is not a lot, but if you are in a sealed suit where this heat becomes trapped, it will not take long for the body temperature to rise to potentially dangerous levels, exacerbated by sweating and an increase in suit humidity. It should be remembered that in the open air, the average human body loses from 0.5L to 2.5L of water per day, although some studies have suggested that the average human may lose in excess of 3L of fluids per day. Within an enclosed suit, fluid loss and sweat production are important factors.

See this table for averaged details[4] The average human has between 1.5m² and 2.0m² of skin area.


Food is a major issue, it is clear that those landing on the Martian surface will burn calories, the astronauts who are in space burn, on average, some 3500 kilocalories per day, but it was estimated that “bouncing” around the lunar surface, the astronauts burnt around 1200 calories per hour, on the surface of Mars, this energy burn may be similar, depending on the work the astronaut is undertaking.

If humans are requiring up to 1200 calories per hour they need high protein and carbohydrate rich food to ensure they maintain energy levels and they do not suffer atrophy caused by the body burning muscle mass to gain energy – that becomes a serious challenge. An average human eats 3667 kilocalories per day in the United States, a little less in Europe, this results in a consumption of around 525Ib (238kg) of food per year, but if the crew that land on Mars require a higher intake, lets say they require a conservative average of 6500 kilocalories, that means they will need the equivilent of around 900Ib (409kg) of food each per year – and all that food has to be taken from Earth and be sustainable for the entire period they are on the surface. The shortest period they could stay on Mars is about 16 months or 500 days – that means they would need about 1650Ib (750kg) of food per person as a minimum – but they also need food for the 9 month journey there and the 9 month journey back home – so they would require around 3500Ib (1590kg) of food per crew member – so a crew of 6 would require around 21,000Ib (9540kg), or almost 10T, just in food stores, and that is not taking extra for emergency contingency.

Assuming they used water recycling, they could minimise water carried, but they average human male requires around 6.5 pints (3.7 litres) whilst the average woman requires 5 pints (2.7 litres) per day – a crew of six, lets assume 3 male and 3 female, would require 34.5 pints (19.2 litres) per day, and this does not include water for washing, food and other requirements. Assuming an 85% recycle rate and the total daily use was kept to 70 pints (40 litres) per person per day, and they lose 15% per day, assuming a total mission length of 1100 days, with a 15% loss rate, which would total 11,550 pints (6,600 litres), thus, they would require to take around 35T of water with them. There may be water on Mars but the crew could not assume they could use it or even access it initially. Get this wrong and people die rapidly – you can survive without food for a very long time, but without water, you die, depending on conditions, within a few short days. We should conclude that working hard on the surface of Mars would require a greater water consumption that the average male or female here in Earth.

Oh, did I mention the surface soils of Mars are contaminated with perchlorates, chemicals that are toxic to life as we know it – they can be washed out of the soils but that would require water – so a long term colony on Mars would require access to reusable and sustainable water sources, either from the surface, near the poles, or from underground sources, some of which have been possibly found, but others may be elusive.

What we are looking at is an environment, which in it’s own way, is as challenging as the Moon, often, it seems, as if people think because it’s a planet and it has an atmosphere, we only need to contend with breathable air and temperature, but the environment on Mars is not only alien, but it is toxic to humans, it would not take long for it to kill a human, or any of the complex life on Earth.

The challenges we face settling on Mars are immense, the logistics of getting all the equipment to Mars is a headache in itself, but keeping humans alive on Mars is a bigger challenge than the Mercury, Gemini and Apollo programs rolled into one.




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