How well did MIT students grade Mars One?

*** I just realized why scientific papers have an abstract. This post is really long and likely to be boring unless you're really interested. So I'm going to write a brief abstract for those of you who don't want to plow through it all.

An MIT team analyzed the Mars One mission plan recently so I've analyzed their analysis. They aren't trying to wreck Mars One, but they generated some sensational headlines and thus need to be answered. Their analysis is built on a lot of guesswork because there is not a lot of detail to the Mars One plan because those detailed studies haven't been done. The MIT paper has a few mistakes, but actually suffers more from the biases of the researchers than from the coincidental mistakes they made.

That was the short version. If you want the details, read on.

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Much has been made in recent days of the paper that an MIT team presented to the International Astronautical Congress a couple of weeks ago. Sydney Do, Koki Ho, Samuel Schreiner, Andrew Owens, and Olivier de Weck did an analysis of the Mars One mission plan as well as they could with the little data that Mars One has released about their plan. You can, and should, read their paper here: http://web.mit.edu/sydneydo/Public/Mars%20One%20Feasibility%20Analysis%20IAC14.pdf to draw your own conclusions. I have examined the paper and drawn my conclusions which I will present to you now.

My first observation regards the intent of the authors. Contrary to what many news outlets have said, I think that it's clear that the authors didn't go into this to stop Mars One nor to say that Mars One's plan won't work. What these students are trying to do is be a part of the conversation about Mars One - and Mars colonization in general - in order to give humanity the best possible chance at making Mars colonization happen. That's a great thing, and I applaud it. It's going to take a lot of people doing a lot of work to make a Mars colony a reality and I'm glad that there are people out there trying to help in whatever way they can.

I believe that these people did the best they could with what Mars One has given them to work with. The trouble is that there is not a lot of detail out there about the Mars One roadmap. I will try to explain why that is, but first a disclaimer: I know nothing about Mars One except what is publicly available. I have applied for a job with them and am waiting for an interview and that gives me exactly zero inside information. On the other hand, as I am an applicant, I have studied the information that is publicly available more than most people out there and I've been around long enough to make some connections between different pieces of the information. So what I have to say here and 79 cents (plus tax) will get you a crappy cup of coffee from the corner store.

I think that there are a few factors that contribute to the relative lack of info on Mars One's plan. It should come as a shock to absolutely no one that the most difficult part of Mars One's plan is the financing. This is going to cost a lot of money for a long time before any returns are seen. While everyone knows they are out trying to raise the needed funds, you may or may not have noticed that the other action they are taking is keeping costs as low as possible. For this reason I think that they are running this endeavor with the minimum possible staff and as such they really don't have time to do things like answer questions about the details of the mission. Between fund raising, television negotiations, upkeep of the website, fund raising, meetings with contractors, fund raising, logistics of interviews, awareness raising, and fund raising there is not a lot of time left for the staff.

Possibly the biggest reason that there aren't a lot of details out is that there aren't a lot of details to put out there. Although started by two engineers, Mars One is NOT a space technology company. These two engineers wanted to go to Mars but they realized that if they wanted to do so they would have to do it themselves because the government agencies weren't going to.  They worked out a plan, went to space technology companies and asked "Hey, can you build this in the next ten years? and how much will it cost?", and they tweaked the plan as needed and started to put it into action. What they and the space tech companies they went to did not do is detailed design studies. They have a concept and they have designs but they haven't yet gotten every nut, bolt, and strip of wire figured out. That will come with time (and money). They have designs for the first (uncrewed? inhuman? personless?) mission because they hired Lockheed-Martin to make said designs. So I think that those of you clamoring for more details are going to have to wait. We've got ten years still. Likewise, MIT's analysis is going to have to remain a very rough analysis because those engineering details have not yet all been worked out.

On to the paper!

On the whole MIT's analysis is an interesting read and has some useful information but I noticed a mistake or so and I noticed the team's preconceptions creeping into the paper here and there.

The first thing that is amiss is what could be a simple oversight, not checking as thoroughly as one should. In Appendix A Habitation Module Assumptions (which is referenced in Section III.I Habitation Module subsection 1 Mars One Habitat Model Set Up and Assumptions) they state that Mars One has "not explicitly specified" the frequency of EVAs from the habitat. The writers therefore assume 5 two-person EVAs of 8 hours duration per week. Just a tiny bit more research on the part of the MIT team would have shown them that Mars One has spelled out in explicit detail the EVA schedule. http://www.mars-one.com/faq/health-and-ethics/how-much-radiation-will-the-settlers-be-exposed-to gives a specified EVA frequency of 3 hours every 3 days per settler on average. This is just over 1/3 of the MIT students' assumption. In the interest of getting things closer to right I'd suggest they plug the correct EVA number into their simulation and see what happens, we may need more or less consumables than they thought. I'll grant that this could be a simple oversight. They may not have made the connection of tying EVA frequency to radiation and therefore not known where to look. I, for one, am glad that Mars One did make that connection.

The next issue that I have with this paper is the way they distorted the information Mars One gave about the size of the food growth area. I don't see how well-intentioned individuals can be comparing Mars One's stated 50 m^2 to their 200m^2 in the way that they do. They have completely left the context out of what Mars One stated and thus distorted the results of this paper to make Mars One look worse. I think that if you read the entire statement from Mars One it's pretty clear that they are talking about having 50m^2 of floor space with multiple layers of plants. Which is almost exactly what this study came up with. They suggest stacking the plants into multiple layers in exactly the fashion that Mars One has talked about all along. The MIT team doesn't say how much actual floor space their 200m^2 translates into when stacked up, but the diagram they supplied shows a central four tray stack flanked by two three tray stacks so I'm just going to guesstimate that their stacking method puts their 200m^2 of plants into about 60 - 65m^2 of floor space. I don't know, they obscure that a little by constantly trying to compare their figure of 200 to Mars One's figure of 50. I also don't know if their trying to make such an obviously false comparison is deliberate or simply an anti-Mars One bias coming out, but I can't imagine that it could possibly be a mistake.

What is certainly the most alarming of the findings in the paper is their idea that because of plant respiration the Oxygen level in the habitat would be out of control and result in certain death for the colonists in just 68 days. This issue has been addressed by Mars One so I'll mention it only briefly as a way of pointing out how the MIT team - and, presumably, any group of engineers - thinks. The removal of Oxygen (or Nitrogen, or pretty much any other gas) from air is a widely used technology. In fact, on page 16 of their report they mention a "pressure swing system" so the MIT team is familiar with it. They don't consider it's use to control the Oxygen level in the habitat because it hasn't been rated for use in space. They simply refuse to consider such a device in their plans because it's never been used in space before. There is absolutely no reason to presume for a moment that a pressure swing adsorption unit wouldn't work in an enclosed Earthlike atmosphere in a Martian habitat. There are also ten years between now and the launch of Mars One colonists in which the equipment can be tested. Why didn't the MIT team run their simulation with such tech included? They made plenty of assumptions anyway, why not just for one simulation assume that pressure swing equipment works and see what the simulator says?

From a few of the things that I read in the report it became obvious that this team came into their simulation with a preconception that permanent colonization should not be done until several return missions have been done first. It's clear from their position on growing our own food and from their position on sparing that they have adopted the timid mindset of the bureaucrats at NASA that there is not an acceptable element of risk. I think you can see how far that has gotten us in the last 40 years.

It is a part of Mars One's mission plan that we grow our own food because one of the primary goals of this colony, right after surviving and growing, is self-sufficiency. It doesn't matter if humanity is spread to two planets if we can't survive on the other one. The MIT team has completely missed this point. This is why the idea of shipping all of our food from Earth is not an idea that we want to have to fall back on. In my opinion, bearing self-sufficiency and survival in mind, a prudent mission plan would include all of the food production equipment as is currently planned while carrying along enough food for two years. This gives us a reasonable safety net and allows us to show the bureaucrats exactly how well Oxygen removal equipment works on Mars. It also allows us to test more crops so we won't have only the nine for which there is available data. We can try everything from avocado to zucchini if we want. Furthermore, with an entire year (Martian) before the next landing there will be time to inform the team back on Earth so the next group can bring the right types and amounts of supplies.

As far as sparing goes, the MIT team fails to think in terms of self-sufficiency. They use the standard NASA mindset of setting a time limit for each component and replacing it at said time whether the component needs to be replaced or not. For a very few items - filters come to mind - this is necessary, but in my experience most components will long outlive their "life limit." When it comes to being self-sufficient the phrase "if it ain't broke, don't fix it" is an important one to live by.

Their sparing strategy is also flawed by their failure to take into account the fact that redundant system needs will likely have a limit. Consider this: Each set of equipment is being sent with another complete working set for redundancy purposes. When the second crew arrives there will be two sets of equipment in use and two redundant sets. When crew three arrives there will be three sets in use and three redundant. Granted that eventually the first crew's equipment becomes irreparable, still there comes a point when redundancies are overdone and each new crew will not necessarily have to have two sets. Maybe it's only every other crew or every third crew. Again the feedback loop from the colony will inform the mission architecture of following missions. The MIT team's analysis in terms of spares is at best a worst case scenario.

While I'm on the subject of spare parts and repairs let me also point out that the MIT team's mission architecture only implements spares at "the lowest level for which data were found ... in general this consists of subassembly-level...". Again this is stuck in the bureaucratic NASA mindset where you pull and replace entire assemblies (even if lack of data has forced that mindset this time) rather than repair things the right way which is this: There's a redundant set of everything. Don't repair a problem by changing out a whole subassembly. Live on your backup, tear down the faulty unit and replace the actual part that has gone bad - the diode, resistor, motor brushes, or whatever gets replaced, not an entire component. It would also be helpful to make all of the equipment with as many common parts as possible. For example if all bolts throughout the habitat were 1/4-20-1" then we only need to have those bolts in stock rather than having 42 different types of bolt. Mars One has mentioned, and I heartily agree, that equipment should also be as low-tech as possible. Keeping the habitat in good repair is going to be crucial to life on Mars and lower tech is generally easier to keep in good repair. I go back to my days repairing sewing machines for a bit of anecdotal evidence here - The actual mechanical mechanism of a sewing machine never needed repair. Oil it once every decade or so and it would run forever. The only parts that ever went out were the motor (rarely, but sometimes) and the electronics (all of the time). An absolutely critical key to a Mars colony staying alive and becoming self-sufficient will be simplicity, always simplicity! Aim for uniformity and lowest technology level as much as is possible.

I will add that there is another piece of equipment that would greatly reduce the mass of sparing. It is not yet commercially available, but at some point in the next ten years someone should design and build it (I would if I had the money). I'm assuming that the colony will have a 3D printer for plastic parts at the least. In the interest of simplicity I'd suggest that all plastic parts be made of the same plastic if it's at all possible. Sparing of plastic parts is then simply a matter of having plastic feedstock for the printer. (here's the piece of equipment I mentioned earlier) If, then, the colony had a device that would grind up/melt down the old parts and return the plastic to feedstock then plastic sparing becomes much much lighter. There will be losses to be replaced, of course, but a Plastic Recycler would be a huge step toward sustainability! You've got ten years people, get on it.

The bottom line here is that MIT's analysis should be taken for what it is: well-intentioned but not really very accurate because of a lack of relevant data and it's coloration by pre-made assumptions. As the next ten years go by and Mars One designs and sends missions we will see what the real data show. I, for one, believe that it will be difficult but it can be done and I remain happy to be among the people who have a chance to be the ones to do it.