Dragonfly leaned against the battery projecting the magic field, letting each rainbow-colored arc of magic ease the dull gnawing in every cell of her body.

Oh, she looked much better than she had when she first came out of the cocoon. Most of the wrinkles were gone. She’d put on weight. Her legs were now less hole and more whole, to make an English joke. So obviously the short daily doses of magic everybody got in the cave worked. She was, very gradually, getting better.

But.

Ninety sols from now, they would leave the cave behind, hopefully forever. After that the batteries that powered these brief recreations of a natural Equestrian environment would recharge only from the ponies themselves- not from the biomass of the cave. Even taking into account the difference between magic generated by thinking life and plant life, the recharge rate would be cut by two-thirds at least, and likely more.

Actually, certainly more, since part of the daily recharge would have to go to topping off the jumbo batteries, which couldn’t ride inside the Whinnybago with them.

Hard times were coming, which is why Dragonfly stayed as close to any magic field projectors that happened to be running.

Sometimes too close. “Dragonfly,” Starlight Glimmer said, “I know you need the exposure, but could you back a few feet away from the battery, please? You’re absorbing too much of the field.”

“Sorry.” Dragonfly reluctantly stepped backwards several paces.

“In fact,” Starlight continued, “could you fetch another battery? I don’t think this one will last long enough to finish the enchantment on all fifteen batteries.”

“I got it.” Before Dragonfly could move, Mark got up and walked over to the row of idle batteries by the cave wall, currently cabled together to help balance the absorption of magic produced by the plants. That was fine by Dragonfly, who didn’t like picking up a sixty-kilo battery in her forehooves. (Okay, it only weighed about twenty-five kilos on Mars, but she’d been sick a really long time.) Lifting it with her limited store of magic, of course, was right out.

Meanwhile, Starlight Glimmer focused her attention on the fifteen jumbo batteries. Each had enough spare space on the top of the crystal to jam in a secondary enchantment linking each battery to one of three forty-kilo slices of quartz. Each of these slices would have five batteries pouring all their power into pushing them away from the batteries at a particular rate of power consumption which, if their calculations were correct, would run about six minutes.

The plan was simple. Mount the slices of quartz around and behind the central engine bell of the first ascent stage of the MAV. The slices had been cut and shaped precisely according to the diagrams in the Ares mission protocols on Mark’s computers to fit in those spots. The fifteen jumbo batteries would be raised in a henge surrounding the MAV descent stage, and by some means- they hadn’t worked that out yet- they would be triggered to switch on half a second after the MAV lifted off the descent stage.

Based on the calculations from experiments back home, if all fifteen batteries worked, there would be fuel reserve in the second ascent stage for maneuvers . They could lose four and still make rendezvous with Hermes without having to use the Sparkle Drive. But that was based on the perfect conditions of Equestria, not the conditions prevailing in a cave on Mars, which was why Dragonfly hadn’t said a word in response to Starlight’s polite request to quit hogging the magic.

In fact… Dragonfly checked the battery charge indicator and said, “Finish this one and stop, Starlight. The battery’s about to run out.”

“Okay.” Starlight had another magic battery under her hooves, and she channeled both that power and the power she could tap from the weak artificial field into crafting the enchantment as strong and deep as she could. The magic flowed from her horn and into the clear quartz, not flickering even for the brief acknowledgment of Dragonfly’s warning. For twenty seconds the spell continued to burn invisible pathways into the stone, and then she cut it off, the enchantment finished. “Okay, shut it down and swap over.”

Dragonfly always hated the moment, even if it was brief, when the Jacolt’s ladder shut down and the magic field dropped. It no longer threatened her sanity when it happened, but it still felt like something which constantly lifted her up had been yanked away, replaced by a brutal, agonizing vacuum.

But she’d had a lot of practice dealing with it, hiding it, denying it. And anyway, it was the work of less than two minutes to remove the kludged aerials from the spent battery, attach them to the full battery, and switch it from recharge to discharge. “How’s it coming?” she asked as she performed this task.

“The three booster targets and ten of the jumbos are finished,” she said. “The enchantments all look good. We’ll have to add conductors to link the battery terminals to the receptor spots on the crystal. The original battery enchantment wasn’t designed to power a second enchantment on the battery itself, not directly.”

“Can you show me the places?”

“Sure. I need to drill a small hole into each of them to hard-mount the conductors, to make sure they stay in contact with the receptor spots in case the jumbos get shaken up by liftoff.”

“We have some power tools.”

“Nothing you or Mark has can cut quartz,” Starlight said. “I won’t be doing the drilling for another week at least, not until we get the charge back from today’s work.”

“Okay. If you’re sure you’re okay to do it.”

“Believe me, it’s a lot easier to put a two-inch hole in quartz than it is to add these enchantments. Ready with the new battery?”

“Yep.”

“Okay. I should be done in another ten minutes.”

“What did you think of the last part of the book?”

“Hm? Oh. Didn’t I say during Story Time?”

“You didn’t say anything. You let us talk.”

“Oh. Sorry, my mind was on this task. And besides, since Mark keeps complaining every time I bring up his species’ inferior system of government, I didn’t think he wanted to hear me talk about how Carrot is clearly meant to be an alicorn prince.”

“Oh, really?” Mark asked. “Because, y’know, ponies often have orange buzz-cut hair, stand two meters tall, carry swords using the opposable thumbs they don’t have-“

“Switch the battery on, Dragonfly,” Starlight sighed.

Dragonfly, having done her little bit to shake up things just enough to keep them interesting, complied.

Author's Notes:

I'd actually intended to have this referred to in passing, but this was the only thing I could think up to write today.