Placing people on Mars has been considered one of NASA’s driving missions for years, however they’re nonetheless within the early phases of deciding what precisely that mission structure will appear to be. One main issue is the place to get the propellant to ship the astronauts again to Earth. Advocates of area exploration typically recommend harvesting the required propellant from Mars itself – some supplies can be utilized to create liquid oxygen and methane, two generally used propellants. To help this effort, a bunch from NASA’s COMPASS crew detailed a number of eventualities of the infrastructure and applied sciences it might take to make an in-situ useful resource utilization (ISRU) system that might present sufficient propellant to get astronauts again to a Mars orbit the place they may meet up with an Earth return automobile. Nonetheless, there are vital challenges to implementing such a system, they usually have to be addressed earlier than the 8-9-year strategy of getting the system up and working can start.
To know these challenges, it’s first important to grasp a few of the necessities the crew was attempting to satisfy. The objective was to offer 300 tons of liquid oxygen and liquid methane to a Mars Ascent and Touchdown Automobile (MALV) being developed at different components of NASA. That a lot propellant is critical to get a crew of astronauts again into orbit, the place they are often met by an orbiting Earth return automobile.
Creating liquid oxygen and methane requires many ISRU techniques, resembling pumps, electrolyzers, dryers, scrubbers, and vital energy techniques, to run all these machines. Some uncooked supplies, resembling CO2, might be pulled from the Martian environment. Nonetheless, the system may also require 150 tons of water, which might be trucked in from Earth or harvested from Mars.
Designing the general system structure is step one in figuring out one of the best methodology for getting sufficient propellant to get the astronauts again off of Mars. A paper from the group compares 5 completely different approaches to fixing that drawback and particulars three of them, specializing in three completely different strategies of getting water to make use of within the creation of liquid propellants on the floor of Mars.
Let’s first take a look at the 2 choices for extracting water regionally on Mars. One structure makes use of a borehole drill to soften subsurface ice and pump it again to the floor, which can be utilized in electrolysis. The opposite structure makes use of floor harvesting strategies, the place soil with a excessive frozen water content material might be sorted, and the water itself melted to offer adequate stockpiles for creating propellant.
Drilling a borehole deep sufficient to entry subsurface ice has by no means been carried out earlier than. It does have some benefits over different water assortment strategies, together with taking much less time and requiring one much less MALV supply of apparatus (i.e., making it decrease price). Nonetheless, it does require extra energy crops and a few specialised gear to be developed.
Amassing water from floor regolith makes use of some applied sciences already being developed at NASA – together with the RAZZOR floor mining system that might be used on the Moon or Mars. Nonetheless, it requires as a lot time and as many launches as delivery water from Earth, with many attainable unknown failure factors within the structure.
By comparability, sending 150 tons of water instantly from Earth, whereas it could be costly by way of launch prices, simplifies the general structure considerably. There would nonetheless technically be ISRU on this state of affairs, because the water would nonetheless be used to create propellant from native Martian sources. Nonetheless, the added step of getting that water regionally can be eradicated.
Even that could be a extra difficult course of than the opposite two choices the crew thought-about, with out as a lot element within the paper because the precise ISRU setups. Mission designers might ship both the methane or each the methane and oxygen from Earth instantly, bypassing the necessity for any ISRU to occur. Whereas these choices require probably extra MALV landers, their total threat is minimized, as the required chemical substances can be obtainable to be used at any level the astronauts would want them. Nonetheless, they’d take longer to arrange – particularly the choice of sending all the propellants instantly from Earth, which might take upwards of 10 years to get arrange.
Different challenges abound for using Martian sources to create propellants – together with restricted areas the place the required water could also be discovered. This geographical restriction may not overlap with the place astronauts could be wanted to do thrilling science, so the architects must prioritize both scientific discovery or derisking the ISRU gear – they possible couldn’t do each.
So, all issues thought-about, if the aim is to ship folks to Mars and again safely, it looks like one of the best, most dependable choice is to ship the entire quantity of propellant from Earth. Nonetheless, in the long term, if humanity plans to make a sustainable presence on Mars, we might want to make the most of native sources. The paper from the COMPASS crew clearly defines a number of methods that might do this, and sometime, it is going to turn out to be the higher choice – simply possibly not fairly but.
Be taught Extra:
Oleson et al – Kiloton Class ISRU Techniques for LO2/LCH4 Propellant Manufacturing on the Mars Floor
UT – A Single Robotic Might Present a Mission To Mars With Sufficient Water and Oxygen
UT – Assets on Mars Might Assist Human Explorers
UT – Mars Explorers are Going to Want air, and Plenty of it. Right here’s a Expertise That Would possibly Assist Them Breath Straightforward
Lead Picture:
Structure Design of the water from Earth supply choice.
Credit score – Oleson et al. / NASA
