The Maretian

by Kris Overstreet

Chapter 141: Sol 238

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“So,” Venkat said, once telephone pleasantries had been exchanged, “Bruce, how was your time off?”

“I didn’t get time off,” Bruce Ng said. “I merely had the luxury of a couple weeks of eight-hour days and sufficient sleep. Sleipnir might be closed out except as presupply for a future Ares VI, but JPL has a lot of other projects going on.”

“Don’t we all,” Venkat agreed. “But seriously, you and your people did a tremendous job, and we’re all grateful.” He leaned back in his chair and continued, “So, did you get my memo about the Ares IV MAV modifications for Watney and his friends?”

“I did. I spent all afternoon and part of the night looking at it,” Bruce said. “And I really wish I didn’t have to tell you this, but your napkin math is wrong. Way wrong.”

“Wrong? How so?”

“The descent stage of a MAV has a thrust-weight ratio of 1.2,” Bruce said. “But that’s before the fuel plant turns one and a half tons of hydrogen into almost twenty tons of fuel and oxygen. Your math assumes the thrust-weight ratio of the hydrazine engines alone is 1.2 with a total vehicle weight of forty-four tons. But a landed MAV, before it begins making fuel, only weighs about twenty-six tons. For a fully fueled MAV, the thrust-weight ratio of the descent stage boosters is about 0.7.”

“Ah.” Venkat ran the numbers in his head, realizing Bruce was dead on target. He’d calculated the rough weight of the total MAV stack while assuming everything else stayed the same. “That’s not good. That’s really not good.”

“Tell me about it,” Bruce agreed. “I’ve been trying various alternatives with the pony engines, but none of those look promising, either. And we can’t do too much lightening of the load if we want to keep the MAV capsule viable for a direct-to-Earth Sparkle Drive backup plan.”

“Keep working the problem, Bruce. It’s in your hands now.” Venkat paused and thought, “If we can’t use the pony engines on the descent stage, where could we use them?”

“I’ll keep working on that,” Bruce said. “The best way would be to drop the second stage single engine and fuel tanks and replace it with one pony engine and three tons of batteries. Those could gradually recharge and refuel the ship in orbit. But I just can’t see how Mark and his friends would get access to that engine safely, even with magic. Also, the specific impulse on a pony engine isn't as good as a methane-oxygen chemical engine, so we'd be trading delta-V right now for delta-V maybe later. I don't know if that works.

"And I really don’t want to add one ounce of non-fuel weight to the first stage if I can help it. The trade-off in delta-V at the start of the burn would not make up for the losses towards the end. Our ascent profile relies on the first stage losing seventy percent of its mass during the burn, Venkat.”

“Do what you can, and keep me and Teddy posted.”

“I’ll do what I can,” Bruce sighed. “In the meantime, ask the ponies if they have any way to make more hydrazine that doesn’t get them all killed.”

There had been a time when Dr. Gaither had ruled Satellite Command, or SatCom, with an iron fist. Then came the aliens, and Mindy Park’s semi-promotion to chief Mark Watney watcher, with authority to override Dr. Gaither’s orders. Gaither had formally protested, and he had been told that he still had NASA’s Earth science orbiters, two solar laboratories, a space telescope, and a Venus orbiter under his absolute command, so quit complaining about Mars. Gaither responded to that by requesting a transfer.

Gaither was in Contractor Relations now, bludgeoning NASA private contractors with the example of the Sol 88 Hab breach and how the long-foreseen dangers of safety-glass space suit visors had finally become real. Tamara Lincoln had taken his place, and unlike the former SatCom boss, Mrs. Lincoln treated Mindy as an important and responsible worker instead of an ambitious scheming hussy. (Not that Gaither had ever used those words, but he’d made his displeasure at losing authority felt quite plainly.)

So instead of walking over to Mindy’s desk and giving her orders, or ignoring Mindy outright, the head of SatCom called her over to the main desk. “Hey, Mindy,” she said. “I just got a strange request from Meteorology.”

Mindy looked over her new boss’s shoulder. “Is this about the dust storm that’s blown up in Amazonis Planitia?” she asked.

“Sure is,” Lincoln said. “They want a detailed tracking of the storm back to its origins. It’s not unprecedented, but it’s really out of season.” Which was true: the really big Martian dust storms tended to blow up in late spring and early summer of Mars’s southern hemisphere, when the planet was closest to the Sun and the Martian weather systems received the most energy. Northern summer happened when the planet was at its most distant point in its elliptical orbit, sharply reducing the potential solar heating. It was the southern summer when things really got hot, with daytime highs routinely breaking into positive degrees Celsius.

But the Sol 6 megastorm had also been unseasonal…

“I can see why,” Mindy said. “But why are they asking us for image analysis? They’ve got a whole department dedicated to Mars weather observation.”

“They didn’t ask us,” Lincoln said. “They asked you.”

“Oh,” Mindy said weakly.

“Welcome to the fast track, Mindy,” Lincoln said. “And don’t be surprised if Crew Systems asks you to help modify their designs for the Sirius tandem rover.”

“At least that would let me actually use my degree,” Mindy muttered.

“Excuse me?”

“Nothing important,” Mindy said. “I’ll get right on it.”

For the first hour Mindy just read up on Martian weather patterns. To have a hope in hell of backtracking the storm, she had to have some idea of where it could have come from. She studied the approximate wind patterns, insofar as Mars had them, and read the highlights of what had been written about Martian weather systems over the years. She didn’t waste time digging into deep meteorology; she’d studied mechanical engineering, which didn’t give her much insight into things like the Coriolis effect.

Interestingly enough, the morning’s observations of the storm in Amazonis Planitia (roughly centered on 10° N, 170° W and moving due west at a blistering sixty kilometers per hour)) suggested that the storm originated in the Tharsis rise- indeed, would have had to roll directly over Olympus Mons itself. That was ridiculous, though. Mindy’s quick reading made plain that three-quarters of the major dust storms Mars produced originated from Hellas Planitia or from the northern plains- low-lying places with comparatively high air pressure, where storms could build up energy before tackling the Martian highlands.

Hellas was in the southern hemisphere; its storms only crossed the equator after they became enormous. And a storm born in the boreal plains would have moved northwest to southeast for quite a distance before catching Mars’s trade wind belt and turning. In either case, the storm shouldn’t be north of the equator but well south of the trade wind interface.

And, most notably, although Martian dust storms could expand with lightning speed, they tended to move at a glacial pace. This one was flying by Martian standards- like spring or autumn cold fronts blasting into the Houston area at thirty or forty miles per hour, driving thunderstorms ahead of them.

This storm was all wrong. It matched nothing in the quick dip she’d taken into Martian weather.

But it bore striking similarities to the Sol 6 disaster.

I can guess why they wanted me to work on this instead of doing it themselves.

Mindy called up the weather photos of Tharsis for the previous day and got to work.

Author's Notes:

Little Rock Comic Con... is not going to pay for my speeding ticket. It's not even paying for itself.

Not much writing tonight, but that's because I was thrashing out math.

Next Chapter: Sol 240 Estimated time remaining: 14 Hours, 54 Minutes
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