“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.
I have been surprised reading the story that NASA would carry on with things like the other Ares missions, rather than the whole programme screeching to a halt so all resources can be focused on rescuing Mark.
So! Looks like NASA is going to learn about magic-induced dust storms.
I wonder if this knowledge will somehow help solve the thrust to weight issues.
It would be kinda poetic, Mars speeding its parting guests with the aid of their magic.
Hmm.
8935681
If they've got resources that they can't repurpose, no reason not to continue using them for their intended purpose. Also, at this point they've basically put all their eggs in the Hermes basket; nothing they can launch at this point will get to Mars before that.
Welp. The speeding ticket sure was unfortunate :(
8935681 Not everything is Mars. JPL has other unmanned space missions in progress or in planning or construction. Watney and his friends get priority, but that doesn't mean everything else stops, especially if stopping the other things won't help Watney.
"stage single engine and fuel tanks replace it with one"
"stage single engine and fuel tanks and replace it with one"?
Ah, sorry the con's not going well for you.
At least the storm doesn't look like, for example, a giant skull...
Crazy Martian weather? This sounds like a job for pegasus weather magic!
8935754
Too bad Spitfire is the only pegasus on the planet.
Status update on song:
i.imgur.com/8FBm1E5.png
i.imgur.com/y2TFXMB.png
I'm waiting on feedback from River Babble on how to proceed with Spitfire's verse, so I've started work on transcribing Kris's version. He sings it a bit faster, but surprisingly, in the same key of D Major.
Yup, they're definitely going to space in a convertible. Statements about "going faster than any living being has ever gone before" confirmed inbound, and it WILL be epic
Also, Little Rock? As in Arkansas? Huh... nice place, such a shame the local convention isn't working out for you...
I still don't get it how a single engine test can trigger a region wide storm, even with magic. Surely weather needs a lot more input than that to be modified in any appreciable way?
My main question is, HOW? HOW does a burst of magic on the exposed Martian surface cause a massive dust storm?
8935912
They mentioned in one of the early chapters that "magic causes light to behave differently and spectrometers won't work", and on their home planet their weather has to be manually controlled. It could be that the strong magic field on their home planet makes their weather behave with excessive force and so manual management is required to keep weather in check, and the same thing is happening to Mars.
8935866
Maybe the weather learned to be "wild" like the everfree?
8935952
This will all end in tears, I just know it.
8936001
I hope it's tears and not tears... as in shredding things.
I have to wonder what would happen if they moved the Death Box next to Dragonfly. I'd bet she'd be out of there in less than an hour.
8935754
You mean like the one that makes magic engines work?
Doomed, dooooooooooomed, I tell ya!
Just how much magical power did those engines dump into Martian atmosphere? Is it an inevitable result of their thrust generation, or is it merely a run-off that could be reduced by refining the design? Does it have the same effect on any atmosphere, and if yes, how did ponies, with their elaborate weather control, not notice that?
8935912
It's been hinted for a while now that worlds are 'alive' in a way, and that while their own world loves the Equestrians, Mars absolutely hates them. A non-magical world has no way to do anything about that, but magic could alter that.
I find myself wondering if the reason Equestria manually controls its weather is because in a high magic environment a Breezy flapping its wings can and will cause a storm somewhere in the world.
8936028
Let's face it... that was a Marvin quote. He meant tears, as in crying
8936274 "It'll all end in tears" was originally an EDDIE (backup personality) quote.
8935802
You are going to release it on YouTube right when it is all said and done?
Even though Mars and Earth will be close during the launch, the food will not last long enough to get back to Earth.
(if I remember correctly they plan on having food for a few days, and with hard rations that is a few weeks, but to get to Earth you need months.)
That's kinda weird question since there is no source of nitrogen compounds on Mars. They may try to bubble chlorine gas (got via chloride electrolysis) through urea solution, but they don't have that much of urea from, well, biological sources, and they don't have that much of electricity and anode material, even if it would work.
8936469
The estimated trip for the sparkle drive to earth is only s few days. Remember it's an attempt at FTL alternative drive system.
Since mass matters very little in zero G could eqestria make a massive ship and pack it with enough life to keep the mana batteries charged even in a non magical environment. especially seeing as the sparkle drive's operation isn't exactly Newtonian. Have Baltimore turn on their search program have Starlight blast a massive spike of magic using several batteries. Big old equestrian ship comes through small lander gets castaways. Sparkles (that's now the word for using sparkle drive travel) over to earth to drop off mark, Queen Chrissy takes credit like a boss runs for President of earth and wins,and that's how we got our new changing overlords.
Oh dear, this isn’t looking good. This monster probably has enough power to rip the hab to shreds.
8936487
if (in sol 180):
is correct then the Sparkle Drive is capable of moving 5 times faster than what the MAV nead to rendezvous with the Hermes, meaning that MAV lift off is not going to be a problem.
8936506 The Sparkle Drive doesn't alter existing momentum. If you shut your other engines off and activate the Drive, then when you turn the Drive back off the momentum is unchanged. So the MAV must build up the speed to match Hermes separate of, and independent of, the speed the Sparkle Drive is capable of.
8936532
Does the sparkle drive scale with mass?
Also, if it can slow down that craft from a few hundred m/s i don't think it can have a 1.2 t/w ratio.
The mars direct craft, even if not a direct copy, is still a good baseline: It has a 4.6/1 on decent.
Another good comparison could be made with the moon lander: 3/1(Feuled) to 13/1(Last drop of fuel)
However, and this might explain where you get that number, the mars direct lander would have 1.28 on earth.
You can't slow down with that T/W on mars because you would be fighting gravity.
8936532
That's a good idea in moving forward by teleport without altering the speed or momentum of the object you eliminate all the inertia and G forces felt by the occupants. effectively you could sparkle at a speed that would cause 20G's while the occupants only experience 1G or what ever Mars is like .8 G. And also it keeps the stopping momentum to a minimum so no getting splattered at a sudden stop.
8936505 Alien Martian demon cricket mummies are behind it all!
Wait... psychic, telekinetic martian bug things obsessed with their own dominance... looking down on all other life...
Quatermass and the Pit was about CHANGELINGS!!
8936630
again: the sparkle drive is pure teleportation. Nanojumps of the described application,the act of "sparkling" around using the Sparkle Drive, produces a force-less virtual motion.
The ship's position and facing in spacetime is alterable via the Sparkle Drive, but not the ship's speed, or mass, or vector, or rotation.
You can, however, pretend to be in "no clip mode" as if the ship were in a video game, by "sparkling" the ship along a preset path and a preset facing. The ship itself will still possess inertia and continue its previous rotation and vector of travel, but the Sparkle Drive would be constantly resetting the ship's facing and positon smoothly enough so that it would outwardly appear to be moving an entirely different direction with an entirely different rotation.
Yes, this does allow for fake artificial gravity, by spinning up a crentufugal/centripetal habitat ring up to 1g of accelleraton, then "sparkling" the habitat into a single position at every moment in time, letting the habitat still think it is rotating at 1g while ships docking with the habitat would interact with it as if it were not spinning at all, because it isn't spinning with respect to the reference frame of the rest of the universe.
Spooky stuff innit?
8940748
Honestly I'm just excited someone else hopped on the sparkling bandwagon.
It originated in Hellas? Rasputin, Nokris, Xol, WHAT DID YOU DO?!? A Destiny 2 reference regarding the latest DLC, for those not in the know.
8941817 No, it didn't originate in Hellas. Most Martian dust storms do, though, especially the coat-the-whole-planet-with-dust-clouds storms.
8941967
I just realized, even if this thing doesn’t destroy the Hab or anything else that’s vitally important for Mark and the castaways. The thing doesn’t have to breach the Hab or wreck the Rovers or Pathfinder to be lethal. The thing could become an exceptionally rare global dust storm, they do occur on Mars and can last for weeks and can block out ninety-nine percent of all sunlight. That would be catastrophic because how would the Hab receive power if it’s getting so little sunlight?
Ahhhhhhhhhh. HERE it is!
Well.
This can't be good.
Well, I don't know about hydrazine, but they've got plenty of other rocket fuel literally just laying all around. Though they'd have to bash some scrap hull sheeting into heavy-duty trashcans first for it to be of much use to them, I suppose.
That's gonna be hard
I mean, they might, but it'd cost them magic...
Well, that's always an improvement as far as bosses go
Hmm, but the ponies only arrived after it, right? Not like they made that one happen...
9253900 In this universe, the Sol 6 storm was intense but still within Martian norms before the pony ship thrusters turned it into a superstorm during the crash-landing.
9190364
Solid rocket booster fuel is a pain in the rear to make. You’d still need some kind of binder to hold that perchlorate together without it reacting in the process. And then mix it without it blowing up on you. AND THEN fill the rocket body without voids and gaps in the fuel mixture that will cause burn instability that makes rockets go boom...
9370399
Well, they do have two of the original CSP astronauts who know pretty much everything about how their early rockets were built, I wouldn't underestimate them.
Again - 'specific impulse' is not the right term here. I'm not actually sure what is; other places you've used the term where you actually meant 'thrust', but changing an engine's thrust has no effect on delta-v.
Total impulse? Specific impulse of pony engines is... infinite!
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