LOG ENTRY: SOL 197
Sigh...
Just once I'd like something to go to plan, ya know?
Mars keeps trying to kill me.
Well... Mars didn't electrocute Pathfinder. So I'll amend that:
Mars and my stupidity keep trying to kill me.
Ok, enough self-pity. I'm not doomed. Things will be just be harder
than planned. I have all I need to survive. And Hermes is still on the way.
I spelled out a Morse Code message using rocks. “PATHFINDER
FRIED WITH 9AMPS. DEAD FOREVER. PLAN UNCHANGED. WILL
GET TO MAV.”
If I can get to the Ares-4 MAV, I'll be set. But having lost contact
with NASA, I have to design my own Great Martian Winnebago.
For the time being, I've stopped all work on it. I don't want to
continue without a plan. I'm sure NASA had all kinds of ideas, but now I
have to come up with one on my own.
As I mentioned, the Big Three (Atmospheric Regulator, Oxygenator,
and Water Reclaimer) are critical components. I worked around them for
my trip to Pathfinder. I used CO2 filters to regulate the atmosphere, and
brought enough oxygen and water for the whole trip. That won't work this
time. I need the Big Three.
Problem is, they soak up a lot of power, and have to run all day long.
The rover batteries have 18kwh of juice. The Oxygenator alone uses
44.1kwh per sol. See my problem?
You know what? “Kilowatt-hours per sol” is a pain in the ass to say.
I'm gonna invent a new scientific unit name. One kilowatt-hour per sol
is... it can be anything... um... I suck at this... oh fuck it. I'll call it a
“pirate-ninja.”
All told, the Big Three need 69.2pn, most of that going to the
Oxygenator and Atmospheric Regulator. (The Water Reclaimer onlyneeds 3.6 of that.)
There'll be cutbacks.
The easiest one is the Water Reclaimer. I have 620L of water (I had a
lot more before the Hab blew up). I only need three liters of water per sol,
so my supply will last 206 sols. There's only 100 sols after I leave and
before I'm picked up (or die in the attempt).
Conclusion: I don't need the Water Reclaimer at all. I'll drink as
needed, and dump my waste outdoors. Yeah, that's right Mars, I'm gonna
piss and shit on you. That's what you get for trying to kill me all the time.
There. I saved myself 3.6 pirate-ninjas.
LOG ENTRY: SOL 198
I've had a breakthrough with the Oxygenator!
I spent most of the day looking at the specs. It heats CO2 to 900C,
then passes it over a zirconia electrolysis cell to yank the carbon atoms
off. Heating the gas is what takes most of the energy. Why is that
important? Because I'm just one guy and the Oxygenator was made for
six. 1/6th the quantity of CO2 means 1/6th the energy to heat it.
The spec said 44.1pn, but all this time it's only been using 7.35
because of the reduced load. Now we're getting somewhere!
Then there's the matter of the Atmospheric Regulator. The regulator
samples the air, figures out what's wrong with it, and corrects the
problem. Too much CO2? Take it out. Not enough O2? Add some.
Without it, the Oxygenator is worthless. The CO2 needs to be separated
in order to be processed.
The regulator analyzes the air with spectroscopy, then separates the
gasses by supercooling them. Different elements turn to liquid at
different temperatures. On Earth, supercooling this much air would take
ridiculous amounts of energy. But (as I'm acutely aware) this isn't Earth.
Supercooling is done by pumping air to a component outside the Hab.
The air quickly cools to the outdoor temperature, which ranges from -
150C to 0C. When it's warm, additional refrigeration is used, but colddays can turn air to liquid for free. The real energy cost comes from
heating it back up. If it came back to the Hab unheated, I'd freeze to
death.
“But wait!” You're thinking, “Mars's atmosphere isn't liquid. Why
does the Hab's air condense?”
The Hab's atmosphere is 90 times as dense, so it turns to liquid at
much higher temperatures. The regulator gets the best of both worlds.
Literally. Side note: Mars's atmosphere does condense at the poles. In
fact, it solidifies into dry ice.
Problem: the regulator takes 21.5pn. Even adding some of the Hab's
power cells would barely power the regulator for a sol, let alone have
juice to drive.
More thinking is required.
LOG ENTRY: SOL 199
I've got it. I know how to power the Oxygenator and Atmospheric
Regulator.
The problem with small pressure vessels is CO2 toxicity. You can
have all the oxygen in the world, but once the CO2 gets above 1% you'll
start to get drowsy. At 2% it's like being drunk. At 5%, it's hard to stay
conscious. 8% will eventually kill you. Keeping alive isn't about oxygen,
it's about getting rid of CO2.
I need the regulator. But I don't need the Oxygenator all the time. I
just need to get CO2 out of the air, and back-fill with oxygen. I have 50
liters of liquid oxygen in two 25L tanks here in the Hab. That's 50,000L
in gaseous form, enough to last 85 days. Not enough to see me through to
rescue, but a hell of a lot.
The regulator can separate the CO2 and store it in a tank, adding
oxygen to my air as needed. When I run low on oxygen, I can camp out
for a day and use all my power to run the Oxygenator. That way, the
Oxygenator's power consumption doesn't eat up my driving juice.
So I'll run the regulator all the time, but only run the Oxygenator ondays I dedicate to using it.
After the regulator freezes the CO2 out, the oxygen and nitrogen are
still gasses, but they're -75C. If the regulator fed that back to my air
without reheating it, I'd be a Popsicle within hours. Most of the
regulator's power goes to heating the return air so that doesn't happen.
But I have a better way to heat it up. Something NASA wouldn't
consider on their most homicidal day.
The RTG!
Yes, the RTG. You may remember it from my exciting trip to
Pathfinder. A lovely lump of Plutonium so radioactive it gives off 1500
watts of heat which it uses to harvest 100W of electricity. So what
happens to the other 1400W? It gets radiated out as heat.
On the trip to Pathfinder, I had to actually remove insulation from the
rover to vent excess heat from the damn thing.
I ran the numbers. The regulator uses 790W to constantly reheat air.
The RTG's 1400W is more than equal to the task, as well as keeping the
rover a reasonable temperature.
To test, I shut down the heaters in the regulator and noted its power
consumption. After a few minutes I turned them right back on again.
Jesus Christ that return air was cold. But I got the data I wanted.
With heating, the regulator needs 21.5pn. Without it... (drum roll)
1pn. That's right, almost all of the power was going to heat.
As with most of life's problems, this one can be solved by a box of
pure radiation.
I spent the rest of the day double-checking my numbers and running
more tests. It all checks out. I can do this.
LOG ENTRY: SOL 200
I hauled rocks today.
I needed to know what kind of power efficiency the rover/trailer will
get. On the way to Pathfinder, I got 80km from 18kwh. This time, the
load will be a lot heavier. I'll be towing the trailer and all the other shit.I backed the rover up to the trailer and attached the tow clamps. Easy
enough.
The trailer has been depressurized for some time now (there's a
couple of hundred little holes in it, after all), so I opened both airlock
doors to have a straight shot at the interior. Then I threw a bunch of rocks
in.
I had to guess at the weight. The heaviest thing I'll bring with me is
the water. 620kg worth. My freeze-dried potatoes will add another 200kg.
I'll probably have more solar cells than before, and maybe a battery from
the Hab. Plus the Atmospheric Regulator and Oxygenator, of course.
Rather than weigh all that shit, I took a guess and called it 1200kg.
Half a cubic meter of basalt weighs about that much (more or less).
After two hours of brutal labor, during which I whined a lot, I got it all
loaded in.
Then, with both batteries fully charged, I drove circles around the Hab
until I drained them both.
With a blistering top speed of 25kph, it's not an action-packed thrill
ride. But I was impressed it could maintain that speed with all the extra
weight. The rover has spectacular torque.
But physical law is a pushy little shit, and it exacted revenge for the
additional weight. I only got 57km before I was out of juice.
That was 57km on level ground, without having to power the
regulator (which won't take much with the heater off). Call it 50km per
day to be safe. At that rate it would take 65 days to get to Schiaparelli.
But that's just the travel time.
Every now and then, I'll need to break for a day and let the
Oxygenator use all the power. How often? After a bunch of math I
worked out that my 18pn budget can power the Oxygenator enough to
make 2.5 sols of O2. I'd have to stop every two to three sols to reclaim
oxygen. My 65 sol trip would become 91!
That's too fucking long. I'll tear my own head off if I have to live in
the rover that long. Anyway, I'm exhausted from lifting rocks and
whining about lifting rocks. I think I pulled something in my back. Gonna
take it easy the rest of today.
LOG ENTRY: SOL 201
Yeah, I definitely pulled something in my back. I woke up in agony.
So I took a break from rover planning. Instead, I spent the day taking
drugs and playing with radiation.
First, I loaded up on Vicodin for my back. Hooray for Beck's medical
supplies!
Then I drove out to the RTG. It was right where I left it, in a hole 4km
away. Only an idiot would keep that thing near the Hab. So anyway, I
brought it back to the Hab.
Either it'll kill me or it won't. A lot of work went in to making sure it
doesn't break. If I can't trust NASA, who can I trust? (For now I'll forget
that NASA told us to bury it far away.)
I stored it on the roof of the rover for the trip back. That puppy really
spews heat.
I have some flexible plastic tubing intended for minor Water
Reclaimer repairs. After bringing the RTG in to the Hab, I very carefully
glued some tubing around the heat baffles. Using a funnel made from a
piece of paper, I ran water through the tubing, letting it drain in to a
sample container.
Sure enough, the water heated up. That's not really a surprise, but it's
nice to see thermodynamics being well-behaved.
The Atmospheric Regulator doesn't run constantly. The freeze-
separation speed is driven by the weather outside. So the returning frigid
air doesn't come as a steady flow. And the RTG generates a constant,
predictable heat. It can't “ramp up” its output.
So I'll heat water with the RTG to create a heat reservoir, then I'll
make the return air bubble through it. That way I don't have to worry
about when the air comes in. And I won't have to deal with sudden
temperature changes in the rover.
When the Vicodin wore off, my back hurt even more than before. I'm
going to need to take it easy. I can't just pop pills forever. So I'm taking afew days off from heavy labor. To that end, I made a little invention just
for me...
I took Johanssen's cot and cut out the hammock. Then I draped spare
Hab canvas over the frame, making a pit inside the cot, with extra
canvass around the edges. Weighing down the excess canvass with rocks,
I now had a water-tight bathtub!
It only took 100L to fill the shallow tub.
Then, I stole the pump from the Water Reclaimer. (I can go quite a
while without the Water Reclaimer operating). Hooking it up to my RTG-
water-heater, I put both the input and output lines in the tub.
Yes, I know this is ridiculous, but I hadn't had a bath since Earth, and
my back hurts. Besides, I'm going to spend 100 sols with the RTG
anyway. A few more won't hurt. That's my bullshit rationalization and I'm
sticking with it.
It took two hours to heat the water to 37C. Once it did, I shut off the
pump, and got in. Oh man, all I can say is “Ahhhhhh.”
Why the hell didn't I think of this before?
LOG ENTRY: SOL 207
I spent the last week recovering from back problems. The pain wasn't
bad, but there aren't any chiropractors on Mars, so I wasn't taking
chances.
I took hot baths twice a day, laid in my bunk a lot, and watched shitty
'70's TV. I've already seen Lewis's entire collection, but I didn't have
much else to do. I was reduced to watching reruns.
I got a lot of thinking done.
I can make everything better by having more solar panels. The 14
panels I took to Pathfinder provided the 18kwh that the batteries could
store. When traveling, I stowed the panels on the roof. The trailer gives
me room to store another 7 (half of its roof will be missing because of the
hole I'm cutting in it).
This trip's power needs will be driven by the Oxygenator. It all comesdown to how much power I can give that greedy little fucker in a single
sol. I want to minimize how often I have days with no travel. The more
juice I can give the Oxygenator, the more oxygen it'll liberate, and the
longer I can go between those “air-sols.”
Let's get greedy. Lets say I can find a home for 14 more panels
instead of 7. Not sure how to do that, but let's say I can. That would give
me 38pn to work with, which would net me 5.1 sols of oxygen per air-sol.
I'd only have to stop once per five sols. That's much more reasonable.
Plus, if I can arrange battery storage for the extra power, I could drive
100km per sol! Easier said than done, though. That extra 18kwh of
storage will be tough. I'll have to take 2 of the Hab's 9kwh fuel cells and
load them on to the rover or trailer. They aren't like the rover's batteries;
they're not small or portable. They're light enough, but they're pretty big.
I may have to attach them to the outside hull, and that would eat in to my
solar cell storage.
100km per sol, stopping every fifth sol to reclaim oxygen. If I could
pull that off, I'd get there 40 sols. That would be sweet!
In other news, It occurred to me that NASA is probably shitting
bricks. They're watching me with satellites, and haven't seen me come out
of the Hab for six days. With my back better, it was time to drop them a
line.
I headed out for an EVA. This time, being very careful while lugging
rocks around, I spelled out a Morse code message: “INJURED BACK.
BETTER NOW. CONTINUING ROVER MODS.”
That was enough physical labor for today. I don't want to overdo it.
Think I'll have a bath.
LOG ENTRY: SOL 208
Today, it was time to experiment with the panels.
First, I put the Hab on low power mode: No internal lights, all
nonessential systems offline, all internal heating suspended. I'd be
outside most of the day anyway.I detached 28 panels from the solar farm and dragged them to the
rover. I spent four hours stacking them this way and that. The poor rover
looked like the Beverly Hillbillies truck. Nothing I did worked.
The only way to get all 28 on the roof was to make stacks so high
they'd fall off the first time I turned. If I lashed them together, they'd fall
off as a unit. If I found a way to attach them perfectly to the rover, the
rover would tip. I didn't even bother to test. It was obvious by looking and
I didn't want to break shit.
I haven't removed the chunk of hull from the trailer yet. Half the
holes are drilled, but I'm not committed to anything. If I left it in place, I
could have four stacks of seven cells. That would work fine; it's just two
rovers worth of what I did for the trip to Pathfinder.
Problem is, I need that opening. The regulator has to be in the
pressurized area and it's too big to fit in the rover. Plus which, the
Oxygenator needs to be in a pressurized area while operating. I'll only
need it every 5 sols, but what would I do on that sol? No, the hole has to
be there.
As it is, I'll be able to stow 21 panels. I need homes for the other
seven. There's only one place they can go: The sides of the rover and
trailer.
One of my earlier modifications was “saddlebags” draped over the
rover. One side held the extra battery (stolen from what is now the trailer)
while the other side was full of rocks as counterweight.
I won't need them this time around. I can return the second battery to
the trailer whence it came. In fact, it'll save me the hassle of the mid-
drive EVA I had to do every day to swap cables. When the rovers are
linked up, they share resources including electricity.
I went ahead and reinstalled the trailer's battery. It took me two hours
but it's out of the way now. I removed the saddlebags and set them aside.
They may be handy down the line. If I've learned one thing from my stay
at Club Mars, it's that everything can be useful.
I had liberated the sides of the rover and trailer. After staring at them
for a while, I had my solution.
I'll make L-brackets that stick out from the undercarriages, with thehooks facing up. Two brackets per side to make a shelf. I could set panels
on the shelves and lean them against the rover. Then I'd lash them to the
hull with homemade rope.
There'll be four “shelves” total; two on the rover and two on the
trailer. If the brackets stick out far enough to accommodate two panels, I
could store 8 additional panels that way. That would give me one more
panel than I'd even planned for.
I'll make those brackets and install them tomorrow. I would have
done it today, but it got dark and I got lazy.
LOG ENTRY: SOL 209
Cold night last night. The solar cells were still detached from the
farm, so I had to leave the Hab in low-power mode. I did turn the heat
back on (I'm not insane), but I set the internal temperature to 1C to
conserve power. Waking up to frigid weather was surprisingly nostalgic. I
grew up in Chicago, after all.
But nostalgia only lasts so long. I vowed to complete the brackets
today, so I can return the panels to the farm. Then I can turn the damn
heat back on.
I headed out to the MAV's landing strut array. Most of the MAV was
made from composite, but the struts had to absorb the shock of landing.
Metal was the way to go.
Each strut is 2 meters long, and held together by bolts. I brought them
in to the Hab to save myself the hassle of working in an EVA suit. I took
each strut apart, yielding a bunch of metal strips.
Shaping the brackets involved a hammer and... well that's it, actually.
Making an “L” doesn't take a lot of precision.
I needed holes where the bolts would pass through. Fortunately, my
Pathfinder-murdering drill made short work of that task.
Attaching the brackets to the undercarriages of the rover and trailer
was easy. The undercarriages come right off. I bolted the brackets in
place and returned the undercarriages where they belonged. Importantnote – an undercarriage is not part of the pressure vessel. The holes I
drilled won't let my air out.
I tested the brackets by hitting them with rocks. This kind of
sophistication is what we interplanetary scientists are known for.
After convincing myself the brackets wouldn't break at the first sign
of use, I tested the new arrangement. Two stacks of seven solar cells on
the rover; another seven on the trailer, then two per shelf. They all fit.
After lashing the cells in place, I took a little drive. I did some basic
acceleration and deceleration, turned in increasingly tight circles, and
even did a power-stop. The cells didn't budge.
28 solar cells, baby! And room for one extra!
After some well-earned fist-pumping, I unloaded the cells and
dragged them back to the farm. No Chicago morning for me tomorrow.
LOG ENTRY: SOL 211
I am smiling a great smile. The smile of a man who fucked with his
car and didn't break it. This is considerably more rare than you might
think.
I spent today removing unnecessary crap from the rover and trailer. I
was pretty damn aggressive about it, too. Space inside the pressure
vessels is premium. The more crap I clear out of the rover, the more
space there is for me. The more crap I clear out of the trailer, the more
supplies I can store in it, and the less I have to store in the rover.
First off: Each vehicle had a bench for passengers. Bye!
Next: there's no reason for the trailer to have life support. The oxygen
tanks, nitrogen tanks, CO2 filter assembly... all unnecessary. It'll be
sharing air with the rover (which has its own copy of each of those) and
it'll be carrying the regulator and Oxygenator. Between the Hab
components it'll be carrying and the rover, there'll be two redundant life
support systems. That's plenty.
Then I yanked the driver's seat and control panel out of the trailer.
The link-up with the rover is physical. The trailer doesn't do anything butget dragged along and fed air. It doesn't need controls or brains. However,
I did salvage its computer. It's small and light, so I'll bring it with me. If
something goes wrong with the rover's computer en-route, I'll have a
spare.
The trailer had tons more space now. It was time for experimentation.
The Hab has twelve 9kwh batteries. They're bulky and awkward. Over
two meters tall, a half-meter wide, and 3/4 meter thick. Making them
bigger makes them take less mass per kwh of storage. Yeah, it's counter-
intuitive. But once NASA figured out they could increase volume to
decrease mass they were all over it. Mass is the expensive part about
sending shit to Mars.
I detached two of them. The Hab mostly uses the batteries at night. As
long as I return them before the end of the day, things should be fine.
With both of the trailer's airlock doors open I was able to get the first
battery in. After playing real-life Tetris for a while I found a way to get
the first battery out of the way enough to let the second battery in.
Together, they eat up the whole front half of the trailer. If I hadn't cleared
the useless shit out earlier today, I'd never have gotten them both in.
The trailer's battery is in the undercarriage, but the main power line
runs through the pressure vessel. I was able to wire the Hab batteries
directly in. (No small feat in the damn EVA suit).
A system check from the rover showed I had done the wiring
correctly.
This may all seem minor, but it's awesome. It means I can have 29
solar cells and 36kwh of storage. I'll be able to do my 100km per day
after all.
4 days out of 5, anyway.
According to my calender, the Hermes resupply probe is being
launched from China in two days (if there were no delays). If that screws
up, the whole crew will be in deep shit. I'm more nervous about that than
anything else.
I've been in mortal danger for months; I'm kind of used to it now. But
now I'm nervous again. Dying would suck, but my crewmates dyingwould be way worse. And I won't find out how the launch went till I get
to Schiaparelli.
Good luck, guys.