The one where I choose a project …
The first ‘Milestone’ in the Coursera capstone course requires submitting a project proposal – the research question being addressed, where we might find data that we will need, etc. This means I need to settle on a project!
Since I first started thinking about the project I have wanted to analyze Mars data to find suitable landing sites for potential future missions – what’s known as a ‘suitability analysis’ in GIS. There were several reasons, however, that I thought this might be a bad idea: is the question too broad?; is the data I would need available?; do I know what I am doing in ArcGIS well enough to analyze the data? I considered a few other options too: something about the spread or impacts of Coronavirus; a political analysis of Brexit or climate views; some climate change-related satellite imagery analysis. In the end I decided to go with my original idea – we’re going to Mars!
This is the red planet in its purest form, digitally stripped of clouds and dust to reveal the surface in detail and true daytime colour (read more about this image here: MGS MOLA/MOC mosaic). How does NASA/ESA/etc. decide where to send their landers and rovers? How do they evaluate whether scientifically interesting locations can be explored safely? What is ‘scientifically interesting’ in the context of Martian exploration? These are some of the questions I hope to address in this project by using GIS to evaluate a variety of criteria that factor into the landing site selection process for missions like the Mars Science Laboratory (MSL, i.e., the Curiosity rover) and the upcoming Mars 2020 mission (the recently named rover Perseverance).
With a mission like MSL having a lifetime cost of around $2.5 billion, choosing an appropriate landing site is obviously an extremely important decision. The success or failure of the entire mission depends to a large extent on making this choice months if not years before the mission lifts off. Ultimately the choice is a trade-off between two broad sets of factors – engineering constraints that dictate where the rover can be safely landed and operated, and scientific constraints that seek to maximize the scientific knowledge gained from the mission. Engineering constraints include factors such as absolute elevation, latitude, slope, various surface properties, and the dimensions of the ‘landing ellipse’. The primary scientific impetus for missions like MSL (and before that MER – i.e., the rovers Spirit and Opportunity) is the determination of the past habitability of Mars. In other words, did environmental conditions conducive to the presence of life ever exist on the planet. The upcoming Mars 2020 mission will take the next step, and actually search directly for signs of past life (i.e., ‘biosignatures’).
Evaluating some of these criteria on a global scale in a GIS program is relatively straightforward – selecting for elevation, latitude, and slope for example. Other criteria need to be evaluated at a much more restricted scale – for example candidate landing sites will be investigated much more closely for detailed slope analysis and identification of large rocks in the area (landing a billion dollar rover directly on top of a large boulder is generally not advised). The geological criteria will be harder to evaluate at a global scale and this is where my analysis will necessarily have to diverge from the real process. However, with a global geologic map, spectroscopic data on mineral occurrences, and datasets like channel landforms I hope to be able to provide some geologic context to inform the engineering side of the process.
Ultimately I hope to produce a map highlighting the locations that best meet all the available criteria. I will then overlay the locations of the top candidate sites for both the MSL and Mars 2020 missions to see how I did! In the next post I will discuss the engineering and science criteria in more detail and share some of the GIS-ready datasets that are available from NASA.
If you would like to learn more about Mars and the MSL and Mars 2020 missions there is a wealth of information on the NASA website:
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