Resource management on Mars

The HI-SEAS habitat is off the grid. We have solar panels for electricity and tanks for water. Conservation of water, power, and Cheez-its governs much of our life here in the hab.

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That’s me on the ridge. Hi, mom!


Most days, we don’t worry about electricity. The hab sits at 8200′; we tend to be above the clouds. If our batteries have a full charge come late afternoon, they easily last through cooking and crew nighttime activities until the sun hits our panels again in the morning.

Often enough though, fog rolls through all day, or thin clouds sit above our solar panel. On these days, we must conserve to ensure we get enough charge to last the night. Usually it’s enough to be careful with how we cook and to postpone running high-energy appliances.

Every once in a while, we have a truly cloudy day. Although we have a backup generator, we avoid using it. After all, on Mars you wouldn’t be able to get a resupply of propane. On these days, computers are unplugged. Cooking is restricted to minimal hot water/hotplate use. Lights stay off, including lights on our non-science plants.


Our water tanks hold 1000 gallons. We receive a refill approximately every 4 weeks and aim to have 100 gallons left on resupply day. I’ll do the math for you – that works out to 32 gallons per day, or about 5 gallons per person – much more than the 7 liters I thought we were going to have. This is the water we use to drink, cook (including food rehydration and dishes), clean, and maintain our own hygiene. Cutting this to 27 gallons per day allows each crew member one load of laundry per month. Any other use – watering plants, cleaning up in the lab, rinsing the urinal, filling the jacuzzi – also comes out of that monthly budget.

Water conservation affects our everyday small habits. We rehydrate food with just enough water, and water plants with old camel pack water or sterile but non-potable lab water. I’ve been reheating the same water in my hot water bottle for the last two months (it’s not that disgusting, it gets boiled every few days). Many of us use the same dishes several times rather than washing them after every use. But it’s the big-ticket items like showers and laundry where conservation strategies make the most difference.


Officially, we are each allowed 8 minutes of shower per week. Some crew members prefer longer showers less often. Personally, I sponge-bathe most days using about a liter of water that I heat in the kettle. That leaves me enough time to have nice long (well, 2 minute) showers on hair-washing days.

We have a solar water heater that sits on top of our attached storage container. Practically, it takes about a minute for the hot water to make it through the pipes to the shower. A minute is a lot when you only have 8 per week; an entire economy has sprung up around the use of that cold water.


We’ve got a three bucket system.

By the way, all those strainers are for straining rehydrated food.

On the left, you see the soup bucket, so called because the contents often resemble soup. This is where all chunks should be removed from dishes. Dishes then go into the middle bucket, the soap bucket. Here the dishes are soaped and sterilized, then rinsed as much as possible. The rightmost bucket is the rinse bucket. This is the only bucket that gets new water. Water moves left, never right. When the rinse bucket is soapy, or the soup bucket is nearing stew, everybody moves down.


We budget for one load of laundry per month per person. Like on a camping trip, normal societal standards of cleanliness don’t apply in here. That said, I have some non-negotiable standards of my own. I will not wear socks or underwear for more than one day, and I will not wear smelly clothes for general wear.

I’ve found that conserving laundry water is all about managing clothing cleanliness, which is all about not letting dirty things hang out with clean things.

That shirt is a bad influence.

This is quite challenging since we do a lot of dirty things here: EVA, daily exercise, taking out the poop. So personally, I have several sets of clothes in use at any given time. I have my EVA clothes, my exercise clothes, and my regular clothes. I will only put on my regular clothes or my pajamas if I am clean. So managing my own cleanliness is critical to managing my clothing’s cleanliness. Likewise, since we don’t have enough water to wash blankets, I have clean blankets that I only touch with my clean clothes and a dirty blanket that I can use if I’m cold and in my EVA clothes or exercise clothes. Regular clothes rotate in as exercise clothes when they’re too dirty.

Congratulations, you got this far. You win a story.

Many of our conservation habits were formed out of necessity in the first weeks of the mission.

The hab sits a mile up a bumpy gravel road. The water delivery company that supplied the previous mission wasn’t willing to supply ours. So mission management had to find a replacement, but so far all were unwilling to make the trek to the hab. With no water delivery in sight, the crew had to conserve as much as possible. We got down to around 8 gallons per day. Then came an event so memorable it was immortalized in song and poem. The song is unshareable, but I leave you with the poem.

Listen, my children, and I will tell
of the water delivery of Bryan Caldwell
on the 8th of February, HI-SEAS mission 5.
Hardly a fly is now alive  // We had a fly problem…
who remembers that famous day and email.

He said to the crew, “When the water truck
comes up the road to the hab tonight,
hang the covers aloft on the window struc-
ture to block the resupply bots from sight.  // Visitors require covered windows

One in the lab and two by the sea
And they on the opposite side will be
ready to drive around to the sim
where all of the water tank’s levels are grim
to fill each one of them up to the brim.”

It was five by the kitchen clock
When the news arrived at the habitat:
T-minus-fifteen to the cheeky knock
Of the robots at the water tank
So listening for any crunch or clank
The crew activates to empty the vat.

They spring to the faucets and open them wide,
At first a trickle and then a tide:
A free for all with each pot, spoon, and bowl,
Each five-gallon bucket and pen cap is full
And a pot from the autoclave besides.

It was five thirty by the kitchen clock.
A water frenzy had truly struck.  // Seriously, it was a madhouse.
Each towel, each shirt, each blanket, each sock
Tumbled in the washing machine,
The shower hosing down each of the crew.
Even the plants get a soaking too.
All assholes and elbows and nosehairs are clean
And still no crunch of a resupply truck.

It was six by the kitchen clock
When each of the crewmates had taken a rinse.
Then to inboxes came a shock:
A second email from Kim on the thread.
The truck will not bring water – instead
Its purpose was mere reconnaissance.

UILA can tell you, the crew devoured  // UILA: our telemetry monitor.
One hundred gallons in half an hour.
A huge red drop that looked even more
ridiculous from conservation before
A number for the record book;
At quick consumption the crew excelled.
All from the email the crew mistook
As a water delivery from Bryan Caldwell.

100 days in the dome

100 days have come and gone. Since January 19, I haven’t seen or spoken to a human other than my crew-mates. I haven’t eaten anything that wouldn’t survive the trip to Mars (or grow on the way). I haven’t set foot outside without a suit on. And I haven’t gone nuts.

Since 100 days seems to be an important landmark in other arenas, I thought I’d give you a summary of the mission’s first 100 days, by the numbers.

500 – rough number of surveys completed by each crew member. They did warn us.

140 – days left in the mission. Almost halfway!

90 – days of exercise videos. When you spend nearly all your time in the same 1200 square feet, exercise is pretty important. The crew followed P90x3 and T-25 from start to finish. As a result…

89 – real honest-to-God push-ups that I did the other day over the course of an hour.

47 – glow-in-the-dark stars stuck to the ceiling of the hab. The ceiling is 18 feet tall. My crew-mates still have no idea how I got them up there. A magician never reveals her secrets.

40 – test tubes filled with my spit, now sitting in the lab freezer, waiting to be tested for stress hormones.

34 – times I stuffed myself into a hazmat suit to venture outside the habitat.

14 – weeks completed of the mission. That means 14 weekends, 14 Monday mornings, and 28 very heavy bags of composted fecal matter scraped from our sanitary facilities.

7 – geological studies completed of the area surrounding the hab. This is mainly what happened on those 34 EVAs. Subjects ranged from cinder cone volume measurement to examination of lava tubes for suitability as radiation shelters.

6 – holidays celebrated in the hab, including two birthdays.

5 – peas grown and eaten. And about 20 more on the way!

4 – hair samples collected from my head. That’s 4 times I let a crew-mate take a shaver to my scalp. These are also now waiting to be analyzed for stress hormones. The things we do for science.

3 – goats spotted, though not all of them alive.

2 – chin-ups completed in a row. See, upsides to hab life.

1 – adventure of a lifetime.

Space bread

In the first week of the mission, I reactivated some sourdough starter given to me by a kind friend. I rehydrated it and administered its first feeding, then went back to my work. When I returned, I found that it had fallen victim to the #1 killer of sourdough: a soapy dish sponge. Lesson 1: label your starter.

Fortunately I had enough dried starter to fail ten or twenty more times, so a couple days later I reactivated some more. I fed it and it grew. I fed it some more, stirred in the water and flour, and licked the spoon before putting it in the dishtub. Lesson 2: no eating the starter. A brief and very fizzy battle for my digestive tract ensued. Laura: 1. Sourdough: 0. But it was a near thing.

Let’s talk about zero-G. A clinostat is an instrument used to simulate low gravity. Basically, it’s a small machine that rotates around one axis that sits at an adjustable angle from vertical. When rotated horizontally, it simulates zero-G. It can be set at other angles to simulate Mars gravity, Moon gravity, anything between zero and Earth. Clinostats are commonly used with microbe cultures or small plants to study the effects of low gravity. A crewmate of mine brought a clinostat to the hab.

Clinostat on loan from ISU

Of course, the first thing we cultured in zero-G was sourdough. My crewmate and I printed up a new capsule for the clinostat more suited to the quantity and consistency of sourdough starter/dough. When the starter had finally grown enough to take some for bread, I pulled off a piece of dough during the final rise and stuck it in the clinostat. We sealed it off with a super high tech system involving a piece of oiled fabric and a rubber band and let it rise. News flash: space bread doesn’t taste any different.

The next order of business was to actually culture the starter in the clinostat. Now, to function properly, a clinostat capsule needs to be completely full at all times. Otherwise, the air pocket moves around and induces shear forces that change how the tumbling simulates low gravity. So we filled the capsule we printed up all the way with starter. Because we were trying to be somewhat scientific, we had a similar volume of starter sitting in a bowl next to the clinostat – this keeps age of starter, feeding, and temperature throughout the day constant. At some point, we’ll print another clinostat capsule identical in shape for use as a control – then air flow to the starter will also be more constant.

Capsule, take 1. Pro-tip, fabric stretches when oiled.

The capsule rotated all day. When it was time for feeding, we took it off and measured the change in mass. Oddly, it had gained mass, whereas the starter on the floor had lost mass. To feed it, we dumped out the starter, stirred in the flour and water, and refilled the clinostat capsule completely with the fed starter. We popped on the cloth cap, and let it go. A few hours later, we checked back in to find starter leaking everywhere. Lesson 3: starter expands after feeding. A lot. Fortunately, my crewmate had thought to put a dish under it in case the cap didn’t hold. I collected up the starter and made dough with it. It was absurdly active – it nearly overflowed the bowl I used to rise the dough. We tried to cultivate zero-G starter once more with elastics over the cap, with the same (delicious but messy) results.

Bread bowls, also possible on Mars.

Remember, we live in a dome. We live off the grid, and we ran into a water emergency. The upshot for the sourdough was that we couldn’t afford the water to clean up the giant mess that it will continue to make in the clinostat until we figure out how to contain the beast. So we had to temporarily discontinue our space bread experiments.

So in the meantime, the next step was to improve our capsule. We designed a new capsule with two parts that could be connected with elastic to allow for expansion of the contents to approximately twice their initial volume. But as you’d expect from a new piece of equipment, it didn’t work at all at first – we left far too little space between the inner and outer parts for them to slide against each other properly. Sanding commenced.

New and improved capsule, now with oil seal.

Water was delivered, and we resumed our experiments. If you’ve ever made something out of papier-mâché, you’ll anticipate our next problem. The sourdough starter, which is mostly flour and water, acted as glue. Solution: an oil seal. But during all this prototyping, a more systemic problem emerged.

Sourdough starter contains a symbiotic balance of yeast and bacteria. The bacteria produce lactic acid – that’s why sourdough is sour. Since the initial rehydration, the bacteria in the starter has proven to be the fitter organism for hab bread life and has completely out-competed the yeast. So I’ve given the sourdough a new lease on life. I’ve started again at step 0, learning from lessons 1 and 2.

Space bread, (hopefully) coming soon to a hab oven near you.

New York Times, episode 2

Episode 2 in the New York Times 360 video series on the mission is released! See it here: The theme of this one is “Getting to know the crew”.

In case you’d like to get to know the crew some more, this seems like a good time to tell you that my awesome crewmates also write about their experiences. You can read their blogs here:


NYC vs dome

The following is an illustrated discussion of the ways in which life in New York prepared me for life in a Martian habitat.

Physical awareness

To operate smoothly in the flow of the sidewalks and subways of New York City, you have to pay attention to the space that you’re occupying. You keep your elbows in, you plan the path you’re walking, you keep your suitcase close. On the subway, you’re cognizant of whether you’re fragmenting the available space on the hand rail, you always take off your backpack, and you might put your book away if it gets crowded. Similarly we must consciously share space in the hab. Some areas are particularly congested. For example, every day we repurpose the main floor space for exercise and must be careful not to kick the experiments, desk items, or each other. Physical awareness is especially important when we suit up for EVAs. The airlock is roughly 8 by 8 feet and at times contains a wagon, EVA equipment, and four people simultaneously pulling on extra-large hazmat suits.


Living space

My first apartment in NY was 350 square feet, shared with my boyfriend, two cats, and frequent houseguests. And by New York standards, it was pretty luxurious. It had a bedroom. The bedroom had a door. For comparison, the hab has about 1200 square feet divided into 6 small bedrooms (with doors!) and a few nice big common spaces.


Like a New York apartment building, the dome is pretty low on sound isolation because of both the size and the material. In that first apartment, I remember being able to hear our upstairs neighbor gently tapping his foot while he played guitar. I also remember being able to hear our upstairs neighbor playing basketball at 3 am, but that’s a different story. We got a lot of street noise too, so I’m both used to an environment with a lot of ambient noise and to having to keep my own noise production low. For the most part, the crew sleeps and wakes at the same time, but when some are sleeping (or filming, or just need some quiet), we need to be conscious of our noise production. The hab has assorted fans and the crew is running a couple noisy experiments, so noise tolerance is also important. That said, one of my favorite parts of living in the hab is having no neighbors other than my crewmates. I can finally blast music and watch movies as loud as I want to! I can stomp if I want to! When the crew came to this realization, we had a stomping party.

Access to nature

I don’t live in the woods. I don’t have much opportunity to hike. New York has beautiful parks, and I even live near one of them, but I admit I don’t go there very often. My main greenery is the street/backyard tree tops I see from my window, and even those go bare come November. So I’m already used to a lack of growing things. The area of Mauna Loa where the hab is situated was chosen in part because it is barren. We do occasionally come across some brave bush when we hike away from the hab, but there is little to no greenery to be seen from the hab itself. As in a city, the exception is the plants we are growing inside. I’ve got some enthusiastic peas planted in one of the gallon cans that used to hold our freeze-dried food. My crewmate has a much more scientific setup. He is growing cabbage, bok choi, and other plants using the same equipment as they do on the ISS.


Constant company

During my commute, I stand in a subway with a hundred strangers. At work, I sit in an open space with my coworkers. When I walk outside, the sidewalks are crowded. When I’m at home, my husband is usually also there. I’m perfectly happy without much alone time. In the dome, we aren’t necessarily interacting all the time, and there are certainly places we can go to be alone; we have individual bedrooms, and there are spaces in the hab (e.g. the attached workshop/storage container) that are less heavily used than the main common spaces. But for the most part I am constantly accompanied by some or all of my crewmates. Even when we go outside in our suits (EVA), we must make sure that at least two go out and at least two remain.

Number of people

I’ve found one way in which living in New York made the transition to the dome more difficult. It’s not the liveliness; I love the energy of New York, but I’m a homebody and there’s plenty of energy and creativity here. It’s not the food; I eat better here than I do at home. Who knew fruits and vegetables freeze-dried so well? It’s the number of people around me. It feels like the time I visited Seattle after moving to New York and the streets were empty at 8 pm. It feels like a meeting when half the team is home sick. Or like a morning Queens-bound E train car with two other riders. Occasionally even now, 7 weeks in, the crew will be sitting all together and I’ll get a strong feeling that somebody is missing. I’ll count heads, or name names. Everyone is present, but the feeling persists. Where is everybody?


On surreal experiences

Sometimes during the day, I sit at my desk, reading and responding to email, drinking coffee, listening to whatever my crewmates are listening to. Then I abruptly come to the realization that I’m sitting in a geodesic dome on the side of a volcano miles from any person other than the crew of 6, and that I will be doing so for another 7 months. This realization does not make me question my life choices.

Other times I am standing in the kitchen, microwaving leftovers and I remember that we live with a box that contains 36 large cans of freeze-dried salmon, 23 bags of raisins, 20 jars of ghee, 18 of gallons of freeze-dried applesauce, enough Tang to water the NFL, and a bag of broccoli big enough to hold a comfortably seated person. And 53 cans of SPAM. Yes, I counted. Maintaining an accurate inventory is important when you’re planning your food supply this far in advance.

In the afternoon, you’ll find me exercising with the crew, music blasting, and I suddenly imagine the hab from the outside: a camouflaged dome alone in miles of lava field, pumping out stomping sounds mixed with Chili Peppers or Beyoncé or whatever happens to be on. Then I imagine a similar hab on Mars, the sound dimmed by the thin atmosphere.

Silly experiences get a notch weirder. I’ll be writing a silly song with my crewmate and we’ll be laughing at some line we made up, and it’ll get funnier when I remember that earlier that day I scraped a week’s worth of excrement out of the composting toilet, bagged it, and stuck it in a tub to wait until the next time we don our “space suits” and haul it down to our storage container where it will sit until the resupply “bots” pick it up some time in the next few months.

Other surreal experiences are more direct. We were assigned our first geology task. In order to accomplish it, we needed to walk along a ridge formed by spatter from a series of cinder cones to collect GPS data. Two crewmates and I strapped into our green hazmat “space suits”, complete with fans, GPS, cameras, radios, and snacks. We waited in the airlock for decompression to finish. We stepped out of the airlock into a densely foggy, windy landscape. We walked along the ridge – lines of black and red rocks faded away into the fog in all directions. On this particular EVA (extravehicular activity), I was the one responsible for maintaining communication with my crewmate in the hab (habcom) and for making any decisions necessary for the success and safety of the EVA, so I brought up the rear. As I followed my crewmates in their bright green hazmat suits through the fog and the lava, buffeted by gusts, the strangeness of the situation again struck me.

When I first arrived here, the weirdness of living as if on Mars was constantly present. Now it intrudes only occasionally. As hab life becomes the new normal, I’m curious to see whether it ever stops feeling this bizarre.