According to the Mars One Website the mission plan relies on technologies that are 'well tested and readily available’. On the life support systems Mars One co-founder Arno Wielders say that this is acheivable by 'maturing existing technologies', though he goes on to say that these technologies have been under development for 'decades’. It may be that the technologies required to design and build the required life support system are known, in so much as the principles are known. Some of the technologies are operated on Earth in one form or another and some are deployed or demonstrated in the ISS, but that is a long way from being ‘readily available’.
Living on Mars with no return, reliant on resupply missions for spare parts or replacements, is different from operating the ISS. For one thing, the resupply flight time to Mars is several months. The ISS can be resupplied quickly, and in the worst case the ISS crew can abandon the station and return to Earth. There have been 79 resupply flights to the ISS since 1998, about 5 a year. Two of the 79 flights have failed.
Whatever technologies are used for the life support systems on Mars (and that includes the systems required for spacesuits) their reliability has to be very high, and the systems will have to have considerable redundancy and adequate spare parts available.
The maintenance budget of the ISS is around US$3 billion per year. It’s not clear what the cost of resupply missions to support 4 people on Mars might be, but the frequency of re-supply missions could well be limited by financial constraints.
Commentators on the Mars One project sometimes flag up the possible use of additive manufacturing techniques (like 3-D printing) to provide a means of producing spare parts, but this may be a little naïve. Industry uses techniques like direct metal laser sintering to produce 3 dimensional metal parts, including those that may be difficult to make by other methods. A 3-D printer has recently been used on the ISS to make a simple plastic component. However, some components will require manufacturing techniques and materials that are not suitable for additive manufacturing, not least most electronic components. Parts may also require additional manufacturing steps to produce the finished article. Any additive manufacturing device could itself be relatively complex, requiring maintenance and repair, and would have to be suitable and proven for operation in Mars gravity.
In March 2013 Mars One contracted the US company Paragon Space Development Corporation to carry out an initial conceptual design study of the Environmental Control and Life Support System (ECLSS), as well as the Mars Surface Exploration Spacesuit System. On their website, Paragon state that the scope of the study included identifying major suppliers, as well as concepts and technologies that exist today and can be used as the basis for further development.
Paragon are currently developing a system for oxygen production from CO2 and water using Solid Oxide Electrolysis (SOE). Although solid oxide fuel cells have been commercialized, SOE is still a developing technology. There are significant materials issues due to the high operating temperatures required.
The conventional choice for oxygen production is electrolysis of water, a technology used on the ISS and well established commercially for terrestrial applications. Water electrolysis produces oxygen and hydrogen. On Mars the hydrogen can be reacted with CO2 (taken from the Mars atmosphere or recovered from the habitat air system as on the ISS), producing water and methane. The product methane can be vented (or possibly stored) and the water recovered for use within the habitat. A system supplied by UTC Aerospace was delivered to the ISS in 2010, and can produce up to 3 litres of water per day. The unit has been described as being reliable, but has not been without problems.
The ISS water electrolysis unit (operated since 2007) and the CO2 removal system have also had problems. For example, in 2011 the electrolysis unit had operating problems due to the quality of the feed water; the CO2 removal system recently had problems with its operating valves. All these units require on-going maintenance.
Recycling of water recovered from urine and hygiene uses has been practiced on the ISS since 2008, and the system has a capacity to treat a nominal 9 kg/day. Operation requires the addition of chemicals (chromium trioxide, sulphuric acid and iodine). The filtration system and ion exchange resins which are part of the water recovery process have to be replaced routinely, although each have reasonable lives (3-5 years). There have been a number of problems, including mechanical issues and contamination by a class of chemicals (silanes) that was not considered in the original design, but which is present in a number of products used on the ISS.
Clearly the point of running these units on the ISS is to gain operational experience, allowing the design to be improved to achieve more reliable operation. But as of 2012, after some 4 years operation, the water recovery system was still being developed.
The important message is that systems such as these take time to be developed, requiring long term testing under real operating conditions, even when the basic technologies they utilize may be well known.
NASA recognise that for these systems significant development work is required to improve their reliability to the level required for long duration flights. They are intensified chemical processing plants. Even with conventional and well established process technologies, experience shows that changes to plant design can spring unexpected operational problems despite research and testing.
Long term operation is essential if demonstration of reliable operation is to be achieved, and equally important is the operation of the complete system, not just the separate component units. Only when the system is run for sustained periods in the actual environment for which it is intended can its reliability really be assessed.
A great deal of system testing can and should be carried out on Earth and on the ISS. Such testing informs the design of these systems, but proof of long term reliable operation on Mars is essential prior to any deployment where human life is at risk. The Mars One project requires that both the Mars atmosphere and the surface regolith (soil) are used as source materials for the habitat. Tests can be run with simulated feed materials, but operation under Mars gravity and with the actual Mars materials can only be carried out in situ, on the surface of Mars.
The Mars One road map includes a ‘demonstration mission’, launched in 2018. This would be a small stationary lander (weight around 350 kg), based on the successful NASA Phoenix lander, which cost around US$350 million. Such a mission is entirely feasible since it is more or less a direct repeat of the Phoenix mission, albeit with different experiments on board. Lockheed Martin were contracted in December 2013 to perform a conceptual design study under which they will write the detailed project plan for the 2018 mission, and determine the exact budget and program schedule. The cost of this study is $256,000. A year later, there has been no information released about the progress of this contract or its expected delivery date.
The Mars One lander is expected to include units for water recovery from soil and a thin film PV array to provide ‘proof of concept’ (Mars One website). The lander will also carry an experiment selected from proposals put forward by various universities. The demonstration mission seems to have limited value, other than to show that water can be extracted from the regolith local to the lander.
According to Landsorp, Mars One plan to have systems operating on Mars for several years before humans arrive, and accepts that it would be unreasonable to risk life without testing equipment over 'at least a decade'.
It is already less than 8 years before the first cargo mission is due to be launched. Depending on the exact timing of the cargo flights that carry the life support equipment, the systems will have been running on Mars for perhaps 2 years before the first people arrive, possibly significantly less (not ‘several’). This assumes that the idea of setting everything up and getting it running by remote control from Earth before the first crew arrive is actually doable. There is another important point here. The systems may have been operating for only around a year when the first manned flight is launched. If problems arise when the crew are in transit there may be no way back.
There is no doubt that the technologies for the life support system will improve and develop over the years before the proposed first launch in 2022, but it takes time to design and build such systems. To launch in 2022 probably dictates that there is a finalized design in 2020, if not significantly earlier. A proven, suitable system does not yet exist. The system has to be defined, a prototype built and tested, the design refined, with the final system design proven through continuous operation over a period of years, on Earth, on the ISS and preferably on Mars, especially those parts of the system which are specific to Mars.
Research and development projects that use novel technologies tend to take a lot longer than expected – it would be foolish to presume that the development of a new system to sustain human life on Mars is going to be any different.
It is now 21 months since the Paragon contract was placed. There has been no update or any information on when the contract is due to be finished. It seems a long time to complete an initial concept study.
Mock up of part of ISS life support system, including shower rack, waste management rack, Water Recovery System and Oxygen Generation System . [Credit : NASA Image and Video Library]
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