"You're not gonna drop this, are you? Fine." Spitfire slumped. "I'm not just a soldier, Mark. I'm an athlete. I'm one of the twenty-four top fliers in all Equestria. Or I was, before I spent over a year in space." She shook her head. "I've read the parts of your medical papers I can understand. They all say space weakens the body. When you come back you get back most of it with time and work, but never all.
"And then you tell me I've lost twenty percent of my lung capacity? I'm a flyer. A high-altitude flyer. I need every bit of lung function I can get. You might as well tell me that I've had half a lung cut out," she shouted, making a gesture with a forehoof across her upper barrel. "It amounts to the same thing! I'll never have that edge again! I'll never be able to go as fast for as long as I used to." She slumped and finished, "Mark, you just told me I lost the Wonderbolts."
Mark put his arm around the pony's shoulders. "I think I got most of that," he said. "And first off, you don't know you've lost your edge. We studied humans in space for up to two years. Humans, not ponies. We know nothing about pony recovery time or abilities. And you'll be going home to a world full of magic. Who knows what's possible there?"
"I do," Spitfire muttered. "Once you lose the edge, you never get it back. I'm going to be like Wind Rider— an old has-been clinging to lost glory." She slapped a hoof against the frame of the bunk. "I'm too young to be like Wind Rider, darn it! I have ten good years left in me!"
Mark hugged Spitfire a little tighter. "Spits, I'm telling you, it's going to be all right."
"I'm telling you it's not! Don't patronize me, Mark! It's over!" Spitfire, hardened veteran, steel-willed officer with over a decade in the EUP behind her, caught herself sniffling. After a moment she decided she didn't care. "It's over..." she moaned, and buried her face in Mark's side.
And then, to her shock, Mark pushed her away.
Mark, the softest, most annoying person Spitfire could think of, Mr. Cheer Up, Mr. Good Feelings, had pushed her away just as she was going to start crying.
"I'm not going to accept that," he said quietly. "It's not over. You're going to survive this. You're going to go home, and you're going to fly faster and higher than ever before. Because if you don't, Mars wins." He pointed a finger at the Hab wall. "That bastard of a planet out there has been trying to break us for four hundred and some sols. In a hundred and forty sols we'll be on our way home laughing at this fucking planet that thought it could break us. Laughing, do you hear me?"
Spitfire had lost all urge to weep. For the first time she could recall, probably for the first time ever, she heard in Mark Watney's voice the same tone that Cherry Berry had when she was in full Steel Eyed Missile Mare mode. No... like that time when she'd been a cadet at Wonderbolts Academy, and she'd been thinking about washing out after a particularly bad day. She hadn't said anything, but the training officer had sounded exactly like this.
"Look at all the ways Mars has tried to kill us," Mark continued. "Impalement. Explosion. Decompression. Suffocation. Poisoning. Lightning. Starvation. Blunt force trauma. And we're beating it, Spitfire, we're beating the bastard. For four hundred sols we've beaten it. So don't you dare let it have a victory now!" He looked down into her eyes, which had gone as wide as any of the others', and said, "Are you going to let this fucking planet beat you, Spitfire?!"
The answer was so automatic as to be involuntary. "Sir, no sir!"
The response to that was, apparently, tradition in two universes. "I can't hear you!"
"SIR, NO SIR!!"
"Are you going to go home, work hard, get back into shape, and show this planet where it can shove its twenty percents?"
"SIR, YES SIR!"
"Good!" And then the moment was gone, and Mark was his smiling, gentle self again, giving Spitfire another hug. "Now let's quit this touchy-feely remake of Full Metal Jacket and go join the others, okay?"
"Um... yeah," Spitfire said, totally confused. Had what just happened been some sort of prank? Or had she actually touched something in Mark?
She did feel better, so there must be something real in it.
"One thing," Mark asked, "What's so bad about being me? And why do you call me Mark Windy?"
"Not Mark Windy," Spitfire said in English. "A pony. Wind Rider. He was a hero, once. Not more, not now. Old. Angry. Washed up." Another pat phrase, but not one Spitfire liked.
"Okay," Mark said. "I know the type. But that's not you. That's never going to be you."
As Mark walked over to his spacesuit rack, Spitfire could only hope he was right.
Author's Notes:
Mark Watney is never going to be R. Lee Ermey. But he's also a born survivor, and apparently one of his very few buttons involves giving up.
I had no idea where this was going to go at first; I just wanted Spitfire and Mark to have a scene, since Spitfire is far and away the most distant of the Equestrians from Mark. I don't think Spitfire will ever particularly like Mark, but we'll see...
Jump to top
Sol 418
View Online
MISSION LOG — SOL 418
It's been a little while since my last entry, but I've been busy, what with hunting down electrical leaks in the Whinnybago, helping do pre-trip physicals, and doing other prep work. So I've got a lot of ground to cover to tell you how I got where I am now, which is back in the Hab after another attempt at Sirius 7.
It really helps that the skies are clear again— well, except for the fact that it's now considerably colder in the Whinnybago at night. The RTG and the insulation in the habitat compartment help with that, but this morning we woke up in a cuddle-pile, and we definitely didn't go to sleep that way. And getting up and suiting up in the chill was no fun at all, let me tell you. But it's not really uncomfortable yet, so we're dealing with it.
Over the past week I've been monitoring the noontime power output of the solar cells. On Sol 410, with the clouds still in full effect, the panel I tested put out 108 watts at high noon. Today, Sol 418, with the sky clear except for the normal pink haze, we got 122 watts. That's excellent news. So long as we have this kind of weather, we'll get maximum recharge out of the system.
Over the past week we went over the electrical system of the Whinnybago twice and Rover 2 once. We found four bare spots on the wiring and one outright break (in a nonfunctional system, obviously), not counting the four entire wiring harnesses we removed because nothing they led to still functioned. We didn't throw them away, though; they got added to the scrap and tools in the back of Rover 2. There are so many potential uses for wire that I just don't want to part with it unless I have to.
Between that inspection and double-checking that the remaining cut ends are both switched off and insulated, we've secured the circuits about as well as we can do without actually dismantling the pony ship. I mean, more than it already is. The thing already looks like it spent six months at a U-Pull-It parts wrecker yard.
And, finally, we performed the two tests for Sirius 7B. Yesterday we left the Hab on a full electrical charge, one hour before dawn, with the harness for the solar panels on the roof of the trailer disconnected, so that only the RTG was still putting power into the system. Everything else, of course, was pulling power out. We ran until the power readings read 10%, which means more or less 48,600 watt-hours consumed. Distance traveled: fifty-seven and one-ninth kilometers, for a consumption rate lowered to 850 watt-hours per kilometer, probably thanks to the power leaks we patched.
We reconnected the solar panels, spread out the spares from Rover 2, and spent the day more or less as before. We pre-cooked four days of potato rations before leaving, so each round of taters only required about four minutes to bring from freezing to edible. (Quick thought; if we bring in tomorrow's potato rations from the saddlebags to thaw each day, we can cut even that in half.) In every other respect we acted just like before— playing with the computers, talking, reading, recharging suits, whatever. And this morning, when we woke up, the battery charge was within 1% of full.
Yeah! Go team! Protect those pirate-ninjas!
This led to today's experiment; drive back the way we came, with the solar panels disconnected again— basically, run all the same conditions as before— with the motor clutches on the rear two wheels of Rover 2 disengaged.
Here's the logic behind this. The wheel motor systems are designed to produce a relatively low speed but outrageous levels of torque. Bear in mind, Rover 2 by itself hauled the wreck of the pony ship— a weight two and a half times its own. (Okay, it didn't do it entirely by itself. We had a unicorn and a dragon to help over the gullies. But if the ground had been as flat as it looks from orbit, it would have. And if the ponies had used larger wheels for their landing gear, we could have done it a lot quicker than the one kilometer per hour. Seriously, the Ares rovers are fucking beasts.)
Now, the logic is that electric motors have a flat efficiency curve, i. e. that so long as the load isn't zero or too heavy for the motor to budge, it's at or near peak efficiency, and thus pouring all the electricity to one engine or distributing it among four or eight makes no difference. Thing is, that's not necessarily so. In fact, once the load on an electrical engine drops below fifty percent of its rated capacity, its efficiency drops off. Below twenty percent, it becomes outright shitty.
The reason is friction. Friction constantly steals a bit of any engine's efficiency— the bearings rub against each other, they rub against the housings, etc. When you lower the load you lower the electricity needed to move it, yes... but you also raise the percentage of the electricity that's being eaten by that constant friction drain.
And as I said, the engines in each rover wheel are monsters. NASA wanted energy-efficient rovers, but they wanted a vehicle that would be able to climb over bad terrain and get its crew home a hell of a lot more. And the same idiots who gave us safety-glass helmet faceplates and one-use disposable CO2 filters said, "Well, there's no kill like overkill," so they gave us motors which could pull England across the Channel and connect it to France, nearly.
I exaggerate a bit, but the key point is that the rover motors are overpowered. That's a good thing for getting a twenty-six ton load started, but once it's moving it only takes a little juice to keep it moving. The apparent load drops off a cliff, and friction— aggravated by the excess weight of the Whinnybago— starts going all om nom nom on the efficiency. And telling the computer to cut all power to those motors doesn't help, because if you do that the motors immediately become dynamos, producing a massive drag on the other engines that more than eats up any power they produce.
Now, of course deactivating two wheels out of eight is not going to give us a twenty-five percent efficiency boost. First, when we're getting up to speed, all that torque is welcome. As beefy as these engines are, twenty-six tons from a dead start on six motors is a bit above one hundred percent of rated load, so the efficiency takes a hit until we're up to speed. Also, every time we brake the connected motors regain a bit of the electricity we've lost, but the wheels with the clutches disconnected don't do that. Free-wheeling wheels don't turn dynamos. So with the six-wheel configuration we lose efficiency both starting and stopping.
And then there's up-slopes. The six-wheel configuration does not like anything above a one in four upgrade. I actually had to get out four times today and re-engage the two wheel clutches long enough to get us out of gullies we had to cross, because we couldn't find any banks less steep than a thirty degree angle. When we make the trip for real, that represents lost time, which means lost recharge, which means shorter legs of the trip. It also means wasted energy stopping and then accelerating again.
NASA tried the experiment on the streets of JSC (and that must have been a thing for the tourists to see, though I feel sorry for the engineers who had to move their cars out of their on-street parking). They got an efficiency gain of twelve percent in Earth gravity on perfectly flat streets with no obstacles and little braking or accelerating.
So what did we get? Well, yesterday we got 57.11 kilometers on 48,600 watt-hours. Today we got... drum roll... 60.53. That's a 5.5% efficiency improvement, 805 or so watt-hours per kilometer instead of 850. After that we recharged for a couple hours and drove the short distance back to the Hab, which we had to drive past before. And here we are.
Five point five percent helps, but not one hell of a lot, especially when you consider there's going to be a lot of terrain where we won't be able to move without those two extra wheels. And critically, we drove more or less in our own tracks going back to the Hab in that second test, so at least a bit of that efficiency improvement is down to not having to slow down to pick a way around obstacles. (And there's going to be a lot more of those where we're going than there are in Acidalia.)
In short, we can only disconnect two motors if we can count on a really long, mostly level stretch where we can just barrel on through. Otherwise it's not worth the hassle.
Now, to be fair, the issue isn't really power consumption so much as power generation. You can put up with shitty efficiency so long as you have fuel to throw at the problem. And we do have an advantage in that right now Mars is getting rapidly closer to the sun, and will continue to get closer during the trip. To make things better, Schiaparelli is almost on the equator— 3 degrees south latitude. That means, if anything, we'll get a slight gain in power from the solar panels as the trip progresses.
But that's not enough. We don't know what Mars will throw at us next. We might break down for days for some reason. We might find an obstacle NASA hasn't spotted from space that makes us detour. We might have more dust storms— autumn is the beginning of the main dust storm season, as the southern hemisphere warms up and gets really active. We really need that seventy kilometers a day.
