The Maretian

by Kris Overstreet

Chapter 142: Sol 240

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[08:09] JPL: Good morning, Mark, Cherry, Starlight, Spitfire, Fireball. This is Bruce Ng in Pasadena. We’ve begun work on planning the modifications you’ll need to make to the Ares IV MAV when you get to Schiaparelli. It looks like it’s going to take a very long time, because we have to experiment with and simulate all sorts of scenarios we normally wouldn’t consider for an instant.

We’re looking for any possible way to use your ship engines. They produce a respectable specific impulse as per your static test a few days ago. Unfortunately, in terms of mass they’re nowhere near as efficient as the methane-oxygen rocket system we’re using, so we can’t just replace our engines with yours. If we’re going to use them at all, we have to add them to the existing engines somehow.

Our favorite scenario at this time is to use the MAV landing stage as a zeroth ascent stage. But that only works out if we can get the full three minutes the lander engines are rated for. A fully fueled MAV cannot get off the ground using lander thrusters alone, and adding the pony engines and batteries will leave the ship very sluggish on liftoff. If we can’t use the pony engines on it for a full three minutes we have to discard that option entirely.

After that option things get pretty uncomfortable. Our second favorite option is to replace the center first stage engine with one of yours. Our third favorite is to strap all three engines on the first ascent stage the same way we’re currently hoping to do to the descent stage. We really don’t like either of them because it adds weight to the ascent stage, hurting the efficiency of the existing rocket system. If your engines produced the same specific impulse as ours, it’d work, but they don’t come close.

Our least favorite strategy is to throw out all backups entirely (and I DO mean all) including the Sparkle Drive and bet everything on the Hermes rendezvous being absolutely successful. We don’t want to do that, because things happen, and our luck as regards Mars has not been the best recently.

There’s one other option we considered- replacing the single engine on the second stage with one of your engines and three tons of batteries. It would cost a bit of specific impulse, but the trade-off would be that you’d have engines that slowly regenerated. But the difference in speed is too great. We absolutely have to get a ship going to 5.8 kilometers per second that was designed to burn out at 4.1 kps. That leaves us no budget for backups or for slowly regenerating fuel.

Finally, although the Rich Purnell plan called for using the Sparkle Drive liberally to achieve the desired velocity, we’re reluctant to try it unless absolutely necessary. The Sparkle Drive is still experimental, and none of us know what will happen if it’s used in atmosphere or how it will function- if at all- in our universe without the power cascade that caused you to crash in the first place.

So, for any of our preferred plans to be workable, both these things have to be true…

Can you make much bigger batteries, capable of storing proportionally more power, using the salvaged electronics from your ship?

And can you synthesize hydrazine to refill the MAV descent stage’s tanks? We use hydrazine monopropellant for the descent stage because it’s our most reliable engine in terms of ignition. The MAV fuel plant isn’t built to make more, and in any case Mars’ atmosphere has very little nitrogen.

[08:51] WATNEY: Starlight Glimmer speaking. I can try to transmute hydrazine, but it’d be extremely dangerous. The transmutation process would heat up the hydrazine, and that might make it blow up in the tank. Also, there’s a good chance it wouldn’t be pure hydrazine. I’ll have to pass that on to Twilight back home.

As for the batteries, it’s possible. Back home most enchanted artifacts or magic-powered devices have a battery function built in to power things.

It’s very seldom that anyone makes a magic battery for the sole purpose of having a battery. The enchantment is very basic, and yes, the bigger the stone the more it will hold.

The main problems are as follows.

First, the meters on the battery casings are calibrated for a roughly 60 kg cubical crystal. We can make them taller, but the charge readouts will be highly unreliable.

Second, the crystals available are a lot more prone to flaws and cracks than the ones back home. I can’t just pick any big crystal. I’m going to have to search the cave and go after the biggest unflawed crystals I can find. It’s a big cave and there are a lot of huge shafts, but finding a big clear crystal here is already a challenge.

Finally, the casings are designed to protect the crystals if they’re dropped or struck. A hard enough blow will crack a battery, severely diminishing its power if it still functions at all. An outright broken crystal loses its enchantment. A too-large crystal slid into the casing will lose the protection.

How tall do you need the batteries?

[9:17] JPL: Our math, using your revised figures for performance, says that running all three of your engines at full throttle for three minutes would require seventy-two normal sized batteries. That’s too many to mount on the exterior without some disaster happening. We’d prefer fifteen batteries five times as tall as normal if we used your engines on the MAV descent stage. If we strap them to the first ascent stage, they’d need to be at least twice as tall.

[09:46] WATNEY: You don’t ask much, do you? In theory I can do the first one. I really, REALLY don’t know about the second. But I’ll need to do a lot of searching to get them.

[10:13] JPL: Okay. Please get back to us as soon as you can on that. We don’t want to chase dead ends on this. The clock is ticking down.

The last name on the office door in Meteorology was Carter, so obviously some wag had used masking tape to cover the first name and replace it with “John.” The memo taped to the wall next to the door (“QUIT CHANGING THE NAME ON MY DOOR! IT WASN’T FUNNY THE FIRST TIME.”) suggested that this happened often.

Inside the office Mindy found a worried-looking man whose first name was Randall. “Good morning, Miss Park,” he said. “What did you find?”

“I tracked the storm back for two days,” Mindy said. “At least, I think I did, but there really wasn’t much else in the area in the days and locations indicated, so I’m fairly confident. The storm began as a squall on the southeastern edge of Tempe Terra. It proceeded due west until it passed through the gap between Alba Mons and the Tharsis Montes line. It then plunged southwards along the west side of the Montes to circle around Olympus Mons, dropping into Amazonis Planitia and building strength.”

Randall nodded. “Yeah,” he said, “that’s what we got, too.”

“What??” Mindy tossed the printouts she’d brought with her onto Randall’s desk. “You already knew? Then why did you have me do it?”

“Because it’s impossible,” Randall said, a little heat in his own voice. “Tharsis rips apart weather systems. It’s like the great wall of Martian weather. And this storm system had way too much energy to begin with, and it barely lost anything crossing Tharsis.” He saw a map of Mars among Mindy’s printouts and traced the route of the storm. “This track is like a typhoon hitting and then crossing the Himalayas… and picking UP strength in the process. It just doesn’t happen.”

“But it is happening.”

“Yeah, but we needed an outside viewpoint to verify it. This is something we’ve never observed before.”

“Except for Sol 6.”

“Even then. The Sol 6 storm was out of season, but it moved at a normal speed and reasonable strength until the morning of Sol 6. We’d tracked it for three days, ever since it dropped off Arabia Terra. It started out ordinary and turned weird, but this,” he waved an irritated hand at Mindy’s paperwork, “this is weird from the get-go.”

“Okay,” Mindy said, calming down a bit as she began to understand where Randall’s mind was. “So, what’s the forecast?”

“Too soon to say, so far as Watney is concerned,” Randall said. “Right now the storm’s due south of Elysium Mons. If it maintains this blistering speed, it will hit Isidis Basin or the eastern edge of Arabia Terra in about two and a half days. A normal storm would get weakened or caught in the basin, or else turned north around Arabia and forced into the mid-latitude westerlies, turning it back towards Alba Mons.”

“But you don’t think this one’s going to do that,” Mindy said.

“Nope. The way this one’s acting, and the way luck has been lately, I’m betting this has Watney’s name on it. Or if you like, ‘Mark Watney or current resident, Ares III Hab.’ And as soon as I can get an appointment, we’re going to put all of this on Dr. Kapoor’s desk and recommend that we get started.” He picked up a handful of papers and began straightening them.

“Started? Aren’t we already started?”

“Started on hardening the Hab for another Sol 6 storm,” Randall said. “Watney and the aliens have to ride this one out. There’s no MAV available for an abort this time.”

Author's Notes:

Randall Carter is from the book; he's the meteorologist who first brings up the Arabia Terra dust storm.

According to my reading on the subject, no wind has yet been recorded on Mars faster than sixty kilometers per hour. (The Sol 6 storm, at least according to Weir, exceeded 160 kph.) Part of this is due to the thin Martian atmosphere itself, but more is down to the atmosphere's composition. Since the air is over 95% carbon dioxide, and since it's very cold, Martian air is 7% the density of Earth's on the surface... even though Mars has only 1% of the actual air pressure Earth has. The speed of sound on Mars- the point at which air becomes incompressible- is only 260 m/s, as opposed to Earth's 360 m/s.

So yeah, this storm is blatantly unnatural.

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