MISSION LOG – SOL 193
Went out to the cave farm today. It’s actually warm there now- only a few degrees cooler Centigrade than in the Hab. Apparently sealing the cave properly also insulated it more efficiently. I’ve turned down the remaining space heater. I considered uninstalling it, but even if it is springtime on Acidalia Planitia, outdoor temperatures still hit nearly -80 C at night. We might need that heater in here, and the ones we already pulled out too. Better safe than sorry.
We’re a little more than halfway to the next harvest. The alfalfa is recovering beautifully from the cutting a month ago. The potato plants are prospering, and a few are even flowering. Of course that’s a waste, since we don’t need potato seeds- I’ve kept a few spuds safe from freezing in the Hab just in case, so we can start over. If anything I’d like to see the alfalfa blooming, since we only have about a third of the original seed remaining. I would love to get replacement seed, because the ponies absolutely, positively need alfalfa for continued survival. But no, no signs of flower buds.
Oh, and Cherry Berry’s saplings are bifurcating with amazing speed. They look like they’re a year old, maybe two, already. I could almost believe we might get a harvest out of them before we have to abandon this place. (Not that I’m mentioning that to Cherry Berry, since she spends almost as long with the trees as she does with the hay, never mind that there’s five hundred square meters of alfalfa and only one row of saplings. Whatever keeps her sane and focused is fine by me, and I don’t want to fuck it up.)
After we got back to the Hab I discovered we had some homework from the new team at JSC, who have accepted my suggested name of Project Sirius. Go me! My first step on the ladder of bureaucratic achievement! In five years they’ll be painting my name on Teddy Sanders’ door! Well, no, not likely, since the only things I’ve administered are plants, some Eritrean farmers, and five adorable but unpredictable aliens. But a man can dream.
Anyway, the rest of today was about math and engineering. A lot of the math depends on the procedures NASA sent us for testing the power of Friendship’s engines and maneuvering thrusters. And, of course, all the engineering is about how to actually carry those procedures out.
Here’s how that’s going to work. First we have to dismount all three of the ship’s main engines, complete with the replacement engine bells the ponies stole from the MAV landing stage. I then get to take the three remaining intact landing struts off the MDV and use some scrap metal to make a holding cradle for the engines.
Now, according to the rough unit conversions Dragonfly and I whipped up, each of those engines weighs about one and a half tons, conservative estimate. The large rock sample scale maxes out at 500 kilograms. It’s calibrated to Mars gravity, so the readout will show its mass accurately. We put the scale under one foot of the cradle and, in theory, it will show one-third of the weight of the engine plus the cradle.
In order for that to work, of course, the cradle will have to be perfectly symmetrical and the engine perfectly centered inside it. That means precision craftsmanship. The hammer will have to stay at home and read a book for this one. And then, of course, the cradle will have to be absolutely level after the scale is stuck under the foot, because tipping it will change the center of gravity and throw off the results.
That’s a lot of work, and the numbers will still be fuzzy, but not as fuzzy as they are now. More to the point, this method also gives us the best shot at an accurate measurement of the power of those engines. We’ll have the engine hooked up to a couple of Starlight’s magic batteries and controls from Friendship. We kick the engine on at minimum power and, very gradually, we ramp up the power until the scale reads one-quarter its starting load. We don’t want to go farther than that, because the last thing in the world we want is a liftoff of an engine connected to loose things by long cables.
Once we have a reading of what percentage of full power takes away three-quarters of the weight of the whole, we can extrapolate the maximum power from there. Also, we can monitor the power readout of the batteries and get a good idea of how quickly the power drains out. When that’s done, we power down as slowly as we can before the batteries run out, because we don’t want all that weight coming back onto the scale at once. We can’t fix or replace that scale, and if we fuck it up, our only backup plan is to cobble together a sled, pile rocks on it, and test Friendship to see how good it would do at a tractor pull.
The math as we currently have it is like this: one of Starlight’s batteries will run one of the main engines for about four point four seconds if it doesn’t recharge itself. In the pony universe this wasn’t really a problem. The batteries are also passive energy collectors, and in Pony-land space magic energy is literally everywhere. The thing is, each battery weighs about seventy kilos, so in order to power all three engines for one minute at full throttle, you need forty-one batteries. That’s not quite three tons, or about two-thirds the estimated weight of the engines themselves.
Now, that’s not terrible compared to the weight of a liquid-fueled rocket at takeoff- on the contrary. But the problem is, with a liquid-fueled rocket the ship’s weight decreases the longer you fly, so what’s left becomes more effective. But with magic battery powered flight, the weight remains constant. You’re dragging every ounce the whole flight, and the rocket never gets any more efficient.
So why bother? Because so long as the thrust-weight ratio of the ship these things get attached to is higher than 1, they’re worth having along. It’s positive delta-V, and we’re going to need every bit of delta-V we can cobble together to get off this rock. We estimate that these three engines, at full throttle, could just about allow Friendship as it currently is to hover- an estimated forty-five tons. The three engines plus the batteries for one minute of flight add up to a lot less than forty-five tons, which means all that excess thrust goes into pushing up the rest of the craft- which already has engines with a greater-than-1 thrust-weight ratio.
But, again, that’s seven point four tons, give or take two hundred kilograms, of extra mass on the ship that’s only useful for one minute. After that it’s dead weight. And, of course, adding more batteries for a longer flight also adds more weight, which makes the engines less useful. And, finally, there’s a simple matter of space; all this crap is going to have to be bolted, strapped, or glued to the outside of the MAV, and there’s only so much room for that.
Nobody at NASA has said so out loud yet, but it’s pretty obvious that the only way this works is if we re-use the landing stage. The landing stage engines have a thrust-weight ratio of about 1.1, just enough to land the thing after aerobraking and parachutes have done all they can do. With all tanks full, the landing stage has about three minutes of full power flight. Between the hydrazine monopropellant still in the Ares IV MAV’s tanks, the leftovers in the MAV and MDV here, and maybe a little pony magic, we should be able to get one minute of flight out of it and then activate the first stage ascent engines.
I grant you, one minute of 1.1 plus whatever the pony engines contribute isn’t going to be a hell of a lot of actual speed. But it’s speed we otherwise wouldn’t get.
And the whole point of this rigamarole is this: we need to know exactly, or as close as we can get, how much more speed this will be, so that JPL or JSC or whoever can plan the flight profile of the rest of the launch. We need to know how fast we can expect the MAV to be going when the first ascent stage lights and the landing stage gets dumped. All the other modifications to the MAV- lightening the load, adding fuel, whatever- depend on that information being accurate. Get it too badly wrong either way, and we miss our date with Hermes.
So Dragonfly, Starlight, Fireball and I tiger-teamed that for a while, figuring out how we’re going to build the cradle, dismount the engines and control systems, and so forth. Then I sat down to do some more math, and this is a bit more critical.
Based on the first harvest, the next hay harvest should provide enough to extend the ponies an alfalfa-only diet through Sol 520, taking into account the potatoes they’ve been eating so far to stretch the harvests. We already have more than enough potatoes to carry us through to launch day, even if all the food packs got stolen by Murphy. For food purposes alone, in about three weeks both the cave farm and the Hab farm become superfluous.
But that’s not the only thing we need. The cave provides faster magic recharge now than the Hab, so we store most of the new batteries there until we need them. If we lose the cave, we lose a lot of our magic production. That’s important, because we need roughly five times the batteries we currently have to make the Rich Purnell plan work.
Follow me here. The Rich Purnell plan has the five hundred kilo rock sample bay filled with a new Sparkle Drive. Six batteries is four hundred and twenty kilos, leaving eighty kilos for the Drive itself. Forty-one batteries for one minute’s use of the pony ship’s engines at liftoff. And one battery for emergencies, because God knows Mars isn’t going to stop fucking with us even after we leave.
Forty-eight batteries.
We currently have nine.
And even with the cave, the recharge time from zero to full for those batteries is seventeen sols- and we need at least two full batteries to make up to two new batteries. And sealing the cave a few days ago zeroed out the batteries we have, so it’s going to be another twelve sols before any batteries get built at all- and that’s if we didn’t use any magic at all in the meantime. But we have to use magic, because these tests, dismantling the ship, etc.
Argh.
Sometimes I get the feeling that I’m not really alive. I’m just an animated sprite in a resource-management video game. Balance your magic reserves, food stocks, and sanity level, and see how long you can keep Mark Watney alive! Buy now and get the Pastel Colored Aliens DLC for only $4.99!
If I am a video game character, I wish the user would go online and download the fan-made Dejah Thoris mod. Just sayin’.
Well, looks like Watney & Co. have their work cut out for them. Here's hoping for a successful test and (eventually) rescue.
Yeah, blood work is no fun. Especially if you don't have really good veins and they have to poke around for one.
I'm still waiting for Mark to make a 'Construct Additional Pylons' joke with the magic batteries.
Shouldn't the time to make new magic batteries go down with each new one they add?
As I understood it the magic recharge wasn't impacted by how many batteries they were charging but by how much life was present to charge them with.
Because if the magic produced is divided by how many sources are using/absorbing it shouldn't the time to charge raise with each new battery?
OH man, I bet Cherry would HATE to leave behind her Cherry Trees when they have to leave, too bad they can't figure out how to put them into stasis and seal them into a case or something to take them back with them then, that way Cherry won't throw a massive fit with having to leave her cherry tree's behind.
I would buy that DLC.
Yes, all of the yes there. Also, you can of this Mark, all you need is some reference pics and I'm sure Dragonfly can accommodate
Is there a way they can eject dead batteries while ascending, as spent cartridges are from a gun? That would make the flight profile more like a chemical propellant, with the mass reducing as the tanks empty.
Hope the blood work is nothing serious, and looking forward to seeing the commissioned picture!
If you were a game character, I'd strongly advise against letting your users install arbitrary mods. Judging by this audience, you certainly wouldn't be getting Dejah Thoris...
8871696
I'm thinking that as far as simple little mobile games go, 2035 will see a sudden revival of the old Cookie Clicker engine as "Potato Clicker" in which the player attempts to optimize potatoes, alfalfa, and batteries.
ooh new chapter! what hilarity and wonde-
maaaaaaaatttthhhh!
8871696
Yes, we need this
Among my friends and I its an automatic win card in Cards against Humanity
I hate to say it, but their plan seems like a huge waste of resources.
The whole reason why they need so much gosh darned magic is because the magical thrusters are horrifyingly inefficient compared to basically anything else magic can do. So why are they wasting all of this power on thrust when they have much more efficient ways to drive the ship?
Use an anti-gravity/reverse-gravity spell instead (we know they have those). Or use a combination of manual teleportation and the Sparkle Drive to get above the atmosphere where there's no wind resistance before engaging their limited thrust. Or use a shield to create a perfectly aerodynamic profile for the ship. It makes little sense to waste their most powerful resource on such an inefficient means of propulsion.
Would it be possible to construct a dedicated magic battery charger?
A "solar" sail of enchanted carbon nano-tubes that could gather the dregs of ambient mana emanated from every living planet in the galaxy!
8871697
No, because the bottleneck isn't the number of batteries, its the fact that they need to USE the batteries.
They need magic to repair the Sparkle Drive.
They need magic to move the Sparkle Drive.
They need magic to assemble the Sparkle Drive.
They need magic to attach the Sparkle Drive.
And thats JUST the Sparkle Drive. That doesn't include ANY work done on the Amicitas or the MAV or emergencies or "I NEED MAGIC OR I'LL GO CRAZY!".
Oh and they need batteries to make batteries. Oh and Starlight is the only unicorn, and I'm willing to bet anyone here cold hard cash that she gets magic locked again.
8871747
They're inefficient because they were designed for use in an environment where they'd literally have infinite energy available and it didn't matter how efficiently they used it. I imagine an anti-gravity spell would probably be similarly draining on resources, and might well not even give them the one minute burn the engines do- and that's assuming that it can even be cast well enough to do any good in a low-magic environment. Besides, NASA doesn't know that such spells exist at the moment and therefore couldn't take them into account when planning the mission.
Good luck with the blood work.
8871711
8871717
Oh, he'd get Dejah Thoris, alright. For a few minutes. And then he'd get the sort of thing one would usually expect from the scenario "trapped in a slowly failing Mars base with a starving black insectoid obligate sophovore alien". The fan who made that mod was apparently something of a troll.
(Though on a lighter note, yeah, what other be careful what you wish for mods might this audience inflict on him? Romance mods are probably near the top of the list...)
Theoretically speaking couldn't you just rig it so that they drain in series instead of draining all at once (I.E. the full load of the power draw is placed onto one or a few batteries at a time instead of all of them at once) then throw the things overboard later? It's not like any plan they have involves actually recharging them to any sort of usable level, right? I mean, I know it might be hard to take a big 70kg rock and throw it away from a vehicle in flight, but it's certainly possible if you get the math right and have a procedure for it and if NASA is good at anything it's math and procedures.
Hell if Kerbal has taught me anything then if there's a way to mount the batteries radially while doing this then provided that the drag doesn't exceed the trust provided then you could just jettison them off proper asparagus style with some simple magic that costs less to maintain then the delta-v it saves by the removal of the weight. The only thing to keep in mind there is that you need a stern joystick jockey to make sure that everything runs smoothly through the staging, but you also have that too.
I guess the question really is why can't they just get rid of the batteries when they are exhausted and turn back into pretty rocks, besides the obvious "becuase that would be difficult" because if something difficult is the difference between surviving and not then you do your best to try the difficult thing and have a contingency in case it fails.
>inb4 magic means that you can't just run them in series
Also this 8871697
8871747
Twilight pretty casually used a 'reverse gravity' spell while she was running around looking for the Crystal Heart. Why fight Mars when you can make it throw you away, instead?
8871771
Not true. Since the beginning of CSP Twilight has been trying (and failing) to improve the efficiency of the thrusters because even an environment with infinite energy can't provide power to the thrusters fast enough to overcome gravity. A spell literally designed to overcome gravity will obviously be more efficient than one we know cannot do that.
8871758
You totally missed the point of my question/comment
The amount of time to make new batteries shouldn't be constant.
It gets faster as more batteries are made and they have more to use thus lowering their % of available magic used each time a battery is used.
or
It gets slower as the total amount of available magic produced in the farm is divided between more and more batteries.
In the chapter Mark comments that the time to make each battery is constant, which is what my question is about.
It wouldn't make sense if production of new batteries is a priority that they would keep them to a constant production schedule when they could in theory produce them faster over time and then have more and more magic to use in a few months by limiting their use as much as possible now.
If they have 4 they can use those to make 4 more, then they can double next time while still having 5 batteries just for use on other things. which is what my whole question is about, if the magic is limited and is divided between all the batteries it will take longer for each full recharge. If it isn't divided then it should take 68 sols roughly if they start with 4 and use the new ones on production of new batteries. In theory they could make 100+ batteries with 85 sols, but at 68 sols starting with 4 and doubling they would have 64 which is more then they need.
The real limit seems like it should be finding the crystals to use to make the batteries not the magic or the recharge time.
8871782
That was the scenes I was thinking of. And you're right, it was 'reverse gravity.'
8871800
Can a pegasus make a magic battery? Can a dragon make a magic battery? Can a human make a magic battery?
8871697
Yep, the overall recovery time will decrease as they add more batteries, much in the style of Cookie Clicker (confound that game).
You're correct that the number of batteries present doesn't seem to negatively impact their collection efficiency. They seem to act a lot like solar panels that way: so long as the batteries don't "occlude" each other, adding more to the farm has no impact on those already there.
8871781 If they were on a world with infinite parts, tools, etc., it would be no problem at all.
But our heroes have only what's with them plus what magic can provide. So staging the batteries (which, among other things, would require that the batteries NOT be drained equally, but rather in series) would require a lot of ingenuity.
Ah good to see that DT got into the mix there though I always preferred Thuvia.😎
Question what affect will firing the magic engines have besides lift?
Didn't they cause a dust storm firing just briefly last time they fired on there way down to mars.
8871789
She cast the spell on herself and Spike. Probably 100kg at most. We have no idea how that would scale up to 3.5 tons just for the batteries.
So.... are they gonna expand the farm and pack the cave with as much living stuff as possible to maximize the magic recharge?
Wait a minute...we know that air and water can move through the link what about mana since magic is abundant in the pony verse there wouldn't be a need to try to shunt it through the life support link why not use one of suits to blow a magic bubble into our universe.
8871960
that
um
does it work like that?
8871942
Here's the thing; if you scale the magical thrusters down to that 100kg performance, Twilight would have needed a 500kg engine (300kg thruster, 200kg batteries). Twilight's spell is obviously much more efficient, and the only way it wouldn't be is if the spell cost increased exponentially with mass, which wouldn't make sense.
8871991
It doesn't I asked about a similar thing before, the water/air is a plot convenience and can't do anything except water/air.
Because really if they can send water and air there's no reason they shouldn't be able to send anything they want and easily follow the connection to find them, it would make for one heck of a short story.
8871991
I'd be inclined to no.
Magic in MLP is, as far as I can tell, a truly mass-less "thing."
Air and water have mass, however simply arranged they are (a critical part of the exchange system, as I recall, any sufficiently complex molecule like food or something gets completely hashed into worthless goo) so the spell can move them as needed.
I view trying to do the same with straight magical energy as kind of like picking yourself up by the seat of your pants. You can grab your pants all you want, you'll never lift your own feet off the ground.
...unless you happened to be named Pinkie...
When you're rife with devastation
There's a simple explanation:
You're a toymaker's creation
Trapped inside a crystal ball
8872018
yeah but my point is its a simple thing that could easily be overlooked by a pony engineer, "why try to send magic through the link, its everywhere?" i am aware that anything more complex than an H2O gets reduced to base elements but what stops you from say planting an insulated jacolt's ladder right over the intake outlet and revving it up with the backing of say an Alicorn or Changeling Queen. Might make for an omg thank you but you almost killed us moment.
8872056
I suppose, but in the end that will be up to the author and if they want to give a massive boon to the team.
8871810
eurobeat intensifies
i0.kym-cdn.com/photos/images/original/000/434/947/4f5.gif
8872056
Um, that teleport thing is already powered by magic, right? Amp it up, see what happens. Even if 99% is lost to some bullcrap-sci-twi enthropy, you still got 1% of Twilight output. And I say give it a shot.
Also, water telegraph is redundant when you can simply go to sleep and talk to a magical blue moon horse princess.
Psst.
Twilight.
Hey.
Send magical-swan-walking-solar-power-plant-teacher-horse on a probe.
Celestia eats sun to make magic.
Her special talent is literally photosynthesis. Everywhere you send a probe, there is sun, ergo, there is magic.
Btw why isn't she green tho.
Doesn't matter. Send Celestia to Mars, solve two problems at once:
1. Mars now have infinite magic.
2. You get rid of the only alicorn I don't like.
It seems like there's something wrong with Whatney's assertion that "so long as the thrust-weight ratio of the ship these things get attached to is higher than 1, they’re worth having along". Sure, the magic thrusters provide delta-V. But by adding mass, they also reduce the delta-V provided by the rocket fuel on-board. That could easily exceed any gains!
It sounds like the thrusters might be being strapped onto the landing stage and discarded with it when both burn out at the same time, though I don't see it said outright. If that's the plan, and the thruster/battery system's thrust-to-weight is better than that of the ship without them (which at an estimated 6 vs. 1.1 it very much would be) then that's all good.
8872210
Nah, just fire magic burners first, and when those are done, cut the duct tape you fixed em to the rocket with.
Oh what a twist will it be if Watney and co arrive to Ares IV only to have this monstrosity of a rocket blow up.
Have will they be saved, you ask?
They'll become valuable research site for future astronauts, of course.
Hey, I'd play that game... although I might opt to find a mod that adds even more ponies rather than accepting that the only ponies I can have are the ones from the official DLC. Just sayin'
8871718
Cherry Clicker obviously.
And Cherry Berry snuck in the 'cherry tree' fan mod when Watney wasn't looking.
8871903
If that's the case then I would be kind of surprised if it wasn't at least considered. Even if raw physical resources are a limiting factor ingenuity is something they would have a near boundless supply of. That said I agree that it's something that probably would be very difficult to actually do, but my point is that it shouldn't be too difficult to consider to the point at which it can be determined that it is reasonably infeasible.
Like, you don't even have to stage every single one individually, or even have them run in series. Even just jettisoning them after they have exhausted their reserve would be better than nothing and could potentially give them a hell of a lot more delta-v to work with if the margins are otherwise too tight for comfort.
Also
Yes, I do beleive that is what I said. I don't quiet understand why you're repeating that in particular.
8872191
The life support systems aren't really something that you want to mess with just to see what happens since if they fail then they fail, period. As much as it is a plot convenience as things are established in the story it makes sense that they're not trying stuff like that just to see what happens since some of the things that could happen when you start messing with things like that fall under the worst case scenario category.
8870645
on the other hoof a long rambling chapter can break immersion as well the length of the chapter always has its own message to me at least
Burn the batteries in stages and jettison them.
8871747
Or transmute Martian soil into rocket fuel. Remember that problem they had with exploding percholrates?
https://en.wikipedia.org/wiki/Ammonium_perchlorate_composite_propellant
Or, do what Twilight asked them to a couple chapters ago and send out a magic pulse to pinpoint their location. ESA already knows the straight-line direction to Mars, and they heard the last pulse Starlight sent. It just wasn't enough to determine a precise distance. That pulse used up (2 I think?) batteries plus Starlight's reserves. But now they have 9 batteries and it takes 17 Sols to recharge them.
This jury-rigged launch and Hermes intercept plan seems incredibly dangerous to me. And within the timeframe that they have to enact it, they could instead send out half a dozen much larger homing pulses.
If it were me, I would think that a much safer bet.
8872025
or the Lorax
8871960
It's not actually a wormhole at all like a lot of people seem to be thinking. It teleports things, and as magic isn't matter, it can't be teleported.
8872191
The problem with that is the inefficiency loss would probably become other energies (heat most likely if we're dealing with entropy). And any significant inefficiency fraction would likely be enough energy to destroy the life support unit. Then they'd be completely fucked. Also Luna hasn't appeared in any of their dreams so far, so it's safe to assume that her power doesn't extend to parallel universes.
8872298
Transmuting matter to rocket fuel does seem a more efficient way to get thrust since they don't have to take the magic batteries on the rocket for that plan.
The pulse was with 9 batteries though, it was Twilight trying to track the magic used sealing the cave. Though they could still do quite a few larger pulses along the way to the Hermes arrival time. The ESA rescuing them still seems a much safer route overall at this point.