...Ordered by what could happen soonest, to be clear, not by likelihood or severity. Neither starvation nor summer will kill her in the next (dath ilani) week, but they are going to happen, and very likely to kill her, whereas accidents and unseen hazards will happen with lower likelihood but unpredictable timing. 

Speaking of that, she really needs a planet-specific calendar, to retrain her time-intuitions on, constantly converting units to ones she's familiar with but make no sense for this planet is just doing extra math for no reason.

That can go on the list. 

A. INFORMATION GATHERING

1. Calendar: determine year length, determine approx day of year, get timeline until summer solstice

2. Climate model: log daily temperatures & graph approx function, track avg increase per day, track humidity patterns, ??do more math??. 

3. Tides: determine lunar month duration, graph tide timing vs days, track and model tidal range variation

4. Biology survey: categorize local organisms, identify sources of food and materials. 

5. Geology survey: map cave system, look for freshwater sources, assess hazards, find useful materials. 

Lots of basic science. It's relevant to basically all the categories of risk. It's also going to be SO. MUCH. MATH. 

(The parts that involve exploring caves or the ocean might be fun. They're also the most likely to kill her in a stupid accident.) 

B. FOOD

1. Identify & obtain samples of possibly edible plants & animals.

2. Test to rule out obvious toxicity (heavy metals?) 

3. Processing/cooking to minimize untestable toxicity.

4. Experimental protocol - eat & see what happens. 

5. Plan harvest locations & schedule.

6. Food preservation: drying? smoking? pickling? salt? 

Wow. Merrin is going to end up spending SO MANY HOURS putting SO MUCH EFFORT into not starving. 

She's probably somewhat more used to the concept than average, since she's done wilderness survival training and "what if ____ terrible fate befalls this part of Civilization" Exception Handling sims, but none of those were on OTHER PLANETS where the local biomass MIGHT NOT BE DIGESTIBLE, and in a lot of the sims she at least had the ability to go obtain more testing equipment than what she has with her now. And also, it was always just a training scenario, she never actually feared that if she didn't figure it out well enough in time she would die slowly of every micronutrient deficiency at once. 

Yet another way in which she's now feeling a lot more sympathy and kinship with her ancient prehistoric hominid ancestors. Except they still had it easier because at least they were ON THE RIGHT PLANET. And had, like, families and larger social groupings? Merrin has some sort of vague unquestioned sense that in hominid prehistory, a lone hominid without their social grouping would probably not have amazing chances. 

C. SURVIVING SUMMER

1. Improve shelter insulation

2. Ventilation with connected cave system? 

3. Evaporative cooling? 

4. Water immersion (build a pool?) 

5. Setup to minimize need to leave shelter in daylight. 

6. UV protection for morning work. 

7. Cave backup hideout? 

A lot of this is really going to depend on her basic-information-gathering findings.

So far, based on her suit environmental data collection, the relative humidity in this region is wildly variable - nearly 100% whenever the hot afternoon hours coincide with newly exposed wet tidal flats, as low as 30% when it's low tide and the wind is blowing toward the ocean rather than coming from it. Humidity in coastal regions tends higher in summer. Her guess is that an evaporative cooling apparatus would sometimes be marginally helpful on days when the tidal schedule and prevailing winds are in her favor, and mostly it's something you want in deserts and not on land. 

Her armor can do climate control for cooling as well as heating. Humidity will make it work harder but won't render it ineffective, and she's really not going to be limited on solar power. That being said, the suit is not specced for temperatures above 45° C, and she'll need to do some HORRIBLE MATH to her temperature data and make up a climate predictive model to have a sense of when the daytime high will start getting hotter than that, but she's nearly certain that it's going to happen at some point. 

...Oof, she's eventually going to have to flip her rest vs activity times, isn't she. In summer, the best time to be out and about (on land) will be nighttime, in the dark. At least she'll have plenty of stored power to use for artificial lighting and won't be walking around with an improvised flaming torch. 

D. ACCIDENT PREVENTION & RECOVERY

1. Do full inventory, identify single points of failure.

2. Maintenance schedule on critical equipment.

3. Backup plans for critical equipment failures.

4. Pack first aid kit for self-treatment to carry at all times.

5. Backup shelter locations with emergency supply caches.

6. Safety checklists for all routine work, especially potentially dangerous tasks. 

Technically Merrin has all sorts of safety checklists with her various kits! ...Most of them are for medical procedures on, like, patients. Who aren't her. She does not have a checklist relevant to, for example, having to swim down into the ocean to harvest shellfish on a planet where miscalculating the incoming tide would 100% kill her.

She knows the routine maintenance on her power armor, fortunately, she was trained on all of that before it was officially issued to her and she does occasional refreshers. She doesn't actually perform the maintenance herself very often, because she's very busy and because the recommended interval is weekly and her Exception Handling training sims almost never last over a week, but...it's been a week, by dath ilan's calendar. Oops. 

 E. LONG-TERM SUSTAINABILITY

1. Plan for winter: indoor heating (burn local biomass?), non-electrical lighting, winter-version insulation. Food availability & storage? Consider seasonal migration??

2. Replacing tools & equipment: what can be manufactured out of local materials? 

3. Continue improving knowledge & skills??

4. Have enough fun not to get depressed or have a psychotic break.

Ironically, that one was a pretty depressing list to make. 

...She eventually adds one more item. 

5. Figure out how to reason about and test hypotheses for how and why I'm on an exoplanet.

That feels...pretty intractable, right now. Merrin probably knows plenty of reasoning tools to apply to it, it's just...not the kind of problem that, on an emotional level, she knows how to dive into. 

That's okay. It's the bottom item on the list marked 'long-term sustainability'. Not understanding how anything works in broader Reality to explain how and why and, just, what, might in fact get her killed! If there's some kind of hazard she'll only see coming in time if she has the correct model of the situation!

But running out of food or getting heatstroke will definitely get her killed, and at least those are problems that don't feel like quicksand to think about. 

What does that put on her schedule for today?

...What she wants to do is go for an ocean swim, but that's an expedition with a very high risk of Stupid Accidents, and she isn't very prepared. She has a much more eyeballed sense of the tide timings, because she is VERY STUPID and even though understanding the tides is critical to her survival, she hasn't even been consistently writing down the exact moonrise and moonset times.

She's picked up a vague sense: the tide is pretty low but probably still on its way out right now, the moon is not currently in the sky but low tide will probably be in a few hours, and the tidal bore is...sometime between five and seven hours after low tide? And then today's high tide will be...early evening? Probably ish? The tides here seem more offset from the solar day than on dath ilan – they're processing around the clock faster.  

Also: tides VARY. Merrin does know some of the factors. On dath ilan, the spring and neap tides are mostly a result of when the moon and sun are pulling in the same direction - which is easy to gauge by, you know, looking at how far apart they are when they're both up at the same time - with some additional effect from the eccentricity of the moon's orbit, but she wonders if it's flipped here. The planet is probably further from the sun, given that it looks like a hotter sun but they're still overall in the liquid-water habitable zone, and the moon sure looks like it's both larger and closer. If it's a captured smaller planet, and the planet is a bit younger and earlier in its geological history than dath ilan, then it could have significant orbital eccentricity. 

She...can guess at that by trying to measure the angular size of the moon as visible in the sky?

Also, she can determine the tidal variation experimentally. By measuring how high it goes on successive days.  

She'll need a better measurement system than "vaguely looking at the river channel sometimes while doing other tasks." Now is actually a pretty good time to quickly walk down the riverbank a bit and identify some recognizable landmarks at different elevation levels, and then she can track over a few days which ones are exposed when. She probably wants to time her first ocean-exploration trip for a weaker tide day, because the currents will be a little gentler.

And she needs to plan to spend a PRETTY LONG TIME out there, so she'll need a full suit battery, and a full air tank – for this she'll need the additional tank for mixing air while underwater, which she's barely used because she's been mostly using the "filter the outside air and top it up with oxygen" mode, but it will at some point need to be refilled, and since she doesn't actually have a way to separate nitrogen, she'll need to go mess around in the software settings and adjust how it's mixing her air while underwater - and she won't have enough to be underwater the whole time... 

ANYWAY it seems like her main priorities today are: 

- Suit maintenance 

- Inventory her stuff 

- Data collection 

- Math

- Maybe, if she runs out of things to do, and has power to spare: exploring the cave behind her cave? 

She'll get to work. 

The tidal bore rolls in at 12 hours, 8 minutes after sunrise. True high tide arrives...eventually...about 12 hours later (it's hard to gauge as precisely, but the current started to switch direction about then, maybe slightly sooner?) 

The tidal amplitude seems to have dropped significantly a few tides ago. By...a bunch. When Merrin does careful riverbank exploration and finds points to compare with what she remembers from her first day, she determines that there's a recent debris line and new traces of dried salt from wave splashing, and the highest debris is, like, 6-8 meters of elevation above Merrin's somewhat noisy estimate for today's high tide line. The very highest tide must have been in the last few days, since her arrival, and it brought the water to less than 5 meters below the lip of the riverbank. 

Sunset arrives 27 hours and 37 minutes after sunrise, though the hours of useful light, counting predawn and early twilight, extends to more like 29 hours. 

The day actually runs slightly cooler than yesterday, and Merrin loses some of the afternoon peak solar power output to a cloud bank that blows in off the ocean and spends a while intermittently blocking the sun; she only gets 980 Wh. It doesn't rain where she is, but it looks like it might be raining further inland. 

Merrin ends up only wearing her power armor for seven hours in the morning, until the ambient temperature is high enough that her cave is comfy as long as she's wearing literally all of her clothing items, and then for a total of three hours of the rest of the day for her checking-tidal-height trips. The maintenance self-tests take a bit of power, but not a lot. She uses 355 Wh of power, less than she banked today, and finishes the day with over 2400 Wh in her batteries.

She's breathing 17% oxygen with the suit on, now, and ambient air the rest of the time; she finishes the day and still has 225L of O2 in the suit's tank. 

She hasn't seen a hint of the moon literally all day. No data to write down. She might actually want to get up tonight during her awake period, do some stargazing, and see if she can catch moonrise to record the time. 

Inventory: ...her food situation is more hopeful than she had feared. She arrived with enough calories, in meal-bar form, to cover 45 dath ilan days - or 1080 hours, which comes to roughly 17 planetary days - but she managed to forget that her extended provisions box was actually also stocked with a ton of meal replacement powder. It comes in two varieties: Lots Of Glucose with extra electrolytes and branched-chain amino acids, for high activity periods - that was what she put in her suit drinking bladder on day one - and a version that's Mostly Just Micronutrients (vitamins, minerals, essential fatty acids, essential amino acids) and is meant to ensure that, regardless of where most of her calories are coming from, she's covered on her essential dietary inputs. 

Using essential micronutrients as the constraining factor for calculations, she has a 10-day supply of the former and a 30-day supply of the latter – another 40 days total, or 960 hours. ...In dath ilan days. And, of course, she can get the bare essentials with one meal bar per 24 hours, so she can stretch that to 3x. 

...She's also totally been undereating a bit on calories. She's been here for...220 hours, roughly? Nine "days" of food supply, which would predict being down 27 meal bars of her original 135, but she has 112 meal bars left, so she must have only eaten 23 of them.  

112 times 24 hours gets her 2688 hours. Plus 960 is 3648 hours. Divide by the 64-hour planetary day, and she has an entire 57 days of key nutrients covered. If she can get, like, really quite a lot of calories out of the local biomass, and ramp up to that very soon. ...She can't ramp up to it that soon, she'll need an experimental self-testing protocol that starts out with very small amounts to check her body's reaction. 

Assume she needs four planetary days, starting tomorrow, before she can safely get significant calories from other sources. 320 hours. At three bars per 24 hours, she'll need to eat 32 meal bars over that period for optimal nutrition, leaving her with 80 at the point when she can even conceivably drop to one per 24 hours. That's 1920 hours, plus 960 hours of meal replacement powder. 45 planetary days plus four is 49 days total. 

Her default rations give her 3600 calories per 24 hours, which is empirically about right for how much she needs to eat when she's actively doing an intensive training scenario. If she's instead only getting 1200 calories, she needs to make up 2400 calories per 24 hours – until she runs out of bars, at which point she has 1000-calorie pouches of powder, and then 400-calorie pouches once she runs out of the ones with lots of sugar. 

Maaaaaaaaaaaath :(

Eventually Merrin has everything converted to 64-hour days.

She needs, like, 8500 calories per day, probably. She can make do with less, she'll lose weight and then her metabolism will stabilize at a lower point, probably, but she'll be weaker and worse at things, which increases the risk of Stupid Accidents. 

If she uses up her rations in order of Overall Goodness, she'll need...actually pretty close to 4000 calories of literally any composition, but a growing number of additional calories from specific macronutrients; taking a weighted average, she needs to make up close to 6000 calories, 2/3 of which can come from anything, 1/3 of which are constrained to a specific breakdown. She can probably flex on that some, humans can stay healthy on a remarkably varied range of diets, but it would make the adjustment a lot harder, and it'll be more difficult to distinguish bad-reactions-to-toxins from, like, feeling weird and bad because her dietary composition is suddenly enormously different from her previous normal. 

...Okay, possibly getting 6000 calories per local day from ocean biomass starting in ONLY FOUR DAYS is. Overly ambitious. 

Also she's now been doing followup math by artificial (bedtime-mode) lighting for almost an hour after dusk, and she only took a 3.5 hour nap in the afternoon. She's so ready to sleep. 

Merrin wakes up twelve hours later, gets up, takes care of bodily functions – and tries not to feel a burst of mental pain over eating a meal bar, because that's stupid, eating a meal bar right now is on the optimal path to survival, she is not going to improve her odds by starving herself until she has other food sources, and so there's no point in letting her brain get away with punishing itself for making the correct tradeoff. 

She puts on the suit – it's not cold in the cave yet, but the outside temperature is below freezing, and she could put together an outfit involving emergency blankets and her rain poncho that would be comfortable in wintery weather, but she charged the suit nearly to full battery while she was asleep and this way she can log sensor data with it to peruse at her leisure later. 

She goes out to sit on a rock and watch the sky. 

The tide seems to be close to fully out. 

Eventually the moon rises, 42 hours and 42 minutes after sunrise.