Chapter Text
"Prey often induce antipredator behaviors when balancing food acquisition against safety. The starvation-predation hypothesis (SPH) posits that, during food shortages, the risk of starvation requires prey to forego antipredator behavior to increase feeding rates. Such shifts in antipredator behavior may further increase the risk of predation..."
Molina, Francisco J., Justine A. Smith, Emiliano Donadio, Arthur D. Middleton, Jonathan N. Pauli, and Jacob R. Goheen. 2023. “ Food Limitation Reduces Risk Avoidance by Prey, but Does Not Increase Kill Rates in a Simple Predator–Prey System.” Ecosphere 14(11): e4701.
Grace and Rocky were maybe a little too well-informed about Grace’s food situation.
The Hail Mary just wasn't designed to sustain a human for so long after the "end" of the mission. Sure, the nutritional paste the ship pumped into his stomach on the way to Tau Ceti obviously had protein and calories in it in addition to nutrients. It had to, since it was designed to help the crew actively gain muscle during their comas.
Even so, there's a big difference between unconscious muscle-building and the activities of a fully conscious astronaut. If Grace ate enough coma slurry to get the minimum daily calories he needed to stay alive and use his conscious brain and body on a daily basis, he would run out just a couple of months after reaching Erid.
He knew that because he'd done that math a dozen times and accepted this as an inevitability when deciding to double back to save Rocky.
To come home.
As soon as they determined that Grace could safely eat Taumoeba, he started breeding and eating as much of it as he could stomach.
He'd already eaten almost all of his packaged meal supplies at that point. After being tempted by them multiple times, he'd shoved the small box of remaining meals and snacks into a random locker in the storage area. Grace didn't trust his own self-control and asked Rocky to install a lock on it that only Rocky knew how to open. That way, there would still be something left if his supply of nutrition powder (or crew morale) got to a more desperate state. The key was that Grace wouldn't be able to access it unless Rocky agreed it was necessary.
Grace had done a pretty good job so far of pretending the small stash of food didn't exist, but now that the end of the journey was mere months away, he was staring down at the end of his rope. Rocky was starting to remind him of a rotisserie chicken whenever he glimpsed that rusty brown carapace out of the corner of his eye.
Not having him around was always worse, though.
Rocky had been asleep for most of that day, and Grace had successfully distracted himself by doing a full survey and selection of the adult Taumoeba populations in the breeding tanks. This included inspecting them under the microscope, completing a battery of tests on each population, selecting the best samples for the next generation, updating the records for every single tank, and safely storing excess Taumoeba for consumption.
Selective breeding had worked for nitrogen-resistance (and the ability to crawl through Xenonite, unintentional as that might have been), so unsurprisingly, it was working for caloric density as well.
There was plenty of Astrophage in reserve to keep the Taumoeba farms going, but carefully sampling, isolating, and selecting Taumoeba that ate a few more Astrophage before they divided, or gave off 0.2% more metabolic heat than average (if he was lucky) for each successive generation was… tedious work, to say the least.
Fattening up the Taumoeba herds gave Grace something of a purpose (or at minimum, something else to do with his time that wasn't just obsessing over what he would do when he ran out of nutrients). A little over three years in, and the newest generations had 30% more calories per gram than when he'd started. That was definitely something! It at least meant he didn't have to pump it into his stomach near-constantly like he had to do in the first year.
He finished testing his current sample of Tank 7 Taumoeba and the numbers on this batch were looking pretty good. They were averaging 0.12% warmer than the last time he sampled this population. Other indicators looked good, too.
Highest marks of the day! Grace saved half of the selected sample in a small petri dish just in case Tank 8 wasn't doing so hot. Then he reintroduced the remainder to their cozy little atmosphere in the glovebox with a nice big Astrophage meal before sealing up the breeding tank. He pulled his arms out of the rubber gloves and opened the outer door to return the tank to its usual home — aka inside a slightly larger box with a nitrogen isolation layer and a test strip of Astrophage.
Grace checked his watch, then sat back heavily.
He turned his attention back to his workbench where his laptop, microscope, and calorimeter lived. Off to the side sat a large clear flask filled with clear goop. He glared at it.
Grace had tried many times to get more nutrients into the Taumoeba. Every single attempt had been a miserable failure.
Every nutrient he had researched, Taumoeba either didn't have the DNA blueprints to make it, or if they did, they didn't have any of the building blocks required. If he had the lab equipment that would allow him to manipulate DNA, he'd yank out some of his own junk DNA and and try to get that turned on.
Stupid primates, losing the ability to synthesize your own Vitamin C. Oh, sorry, you don't need it anymore? There's an abundance of fruiting plants all around you that you can eat whenever you want? Gee golly, that's so convenient! Why didn't I think of that?
Grace exhaled noisily and decided the Taumoeba won the staring contest. He snatched up the flask in defeat, swiveling his chair 90 degrees to face his "Kitchen", which consisted mainly of a shallow shelf that held a bag of white powder, rolled and sealed with a small plastic measuring scoop inside, and a single solitary spoon.
Movements rote and practiced, he opened the bag, leveled off a scoop, and tapped it into his flask before tossing the scoop back in the bag. He picked up the spoon and stirred the Taumoeba once, twice... just enough to push the powder under the surface.
He put the spoon in his mouth and pulled it out through his lips, grimacing minutely, then brought the flask and tipped his head back.
The Taumoeba goop slipped down his throat without tasting of anything, but at least it managed to (mostly) protect his tongue from the bitter-tasting powder. It felt like thick water, unsubstantial and unsatisfying. He knew it would do little to ease his hunger, and gulped it down as quickly as he could. When he was done, he scraped the flask out with the spoon. Waste not, want not. (Yeah, right.)
Unpleasantries complete, he quickly cleaned the flask, spoon, and every other surface and machine he'd used while testing the sample from Tank 7.
Even though they had customized this collapsible side room in the lab into a "clean room" for all of the Taumoeba equipment, they still took every precaution: clean-up protocols, Astrophage test slides, and a bespoke Nitrogen-bathing air filtration system, courtesy of Rocky. It could even be flooded with Nitrogen, if needed.
Thankfully, they had yet to use that feature. Since they weren't threatening the alien life form with 'death by incremental increases in nitrogen' all the time, it had no incentive to escape. Ergo, there had been no new Taumoeba leaks.
Knowing how adaptable Taumoeba could be, the last thing Grace and Rocky wanted to do was accidentally breed in some new undesirable trait and not have any of the original stock left for seeding Threeworld. Because of this, Tanks 9 and 10 were controls — they only had to be maintained and fed, and Grace handled them on different days to ensure he didn't accidentally introduce any Taumoeba that weren't supposed to mix. He wondered if breeding Taumoeba specifically to be more effective food officially made them a domesticated species?
All that was left for today was Tank 8. Grace was getting tired, but it seemed a shame to stop when he only had one left. So he put on fresh gloves and pulled the tank. Unsealed it inside the glove box and scraped the Taumoeba out into the flask. Passed the flask through the external transition chamber. Scooped out a generous sample from the population and set the rest aside.
He'd probably polish off this flask too, but he liked to wait until after he was done with each round of tests, just in case he fucked up the sample somehow and needed a new one from the same population.
His stomach growled petulantly, kicked into digestive gear but wholly unsatisfied. Like eating a raw carrot at a salad bar and then being whisked from the buffet before you can enjoy anything else.
Grace thought he'd be used to the hunger by now, but if anything, it was getting worse. He'd been getting intense cravings, stomach cramping, and intensely miserable mood swings as his body sent more and more desperate pleas for him to find and eat some actual food.
His rationing was preventing major deficiencies, but he wasn't exactly healthy. Eating the bare minimum for more than three years will do that to you.
He hoped it would be enough.
He hoped he wasn't doing all this work for nothing.
He hoped Rocky's faith in Erid's scientists wasn't misplaced.
Grace fully intended to live out the rest of his life on Erid, however long that ended up being. The end of his life didn't scare him so much anymore, but what did scare him was the idea of his bones falling apart with early-onset osteoporosis, or sustaining so much heart damage that he couldn't maintain his own blood pressure and fainted whenever he tried to stand, or started having seizures —
Grace slapped his hands on the table and cleared his throat pointedly like he was communicating nonverbal disappointment at a student. I can see what you're doing. It's time to make better choices, or I will make them for you.
He quickly prepped a slide with the tiniest drop of Taumoeba and focusing the microscope on it. He pulled the Kitchen laptop over and opened the simplest script he'd ever written: Hit space, number go up. He grabbed a tiny pipette of Astrophage and hovered his other hand over the spacebar. Let the tiny game of Hungry Hippos commence.
He could admit there were some... psychological affects of his dietary restrictions. It probably wasn't healthy to spend as much time as he did poring over the Hail Mary's archives for anything and everything related to nutritional deficits or outright starvation.
Medical textbooks, academic papers, Web MD articles... he'd read everything he could find. Multiple times. Tried to convince himself (and Rocky) that he was just doing research, preparing for the worst, making sure they knew exactly what they needed to prevent long-term side effects.
He couldn't stop looking, though. He'd get anxious, pull them up for reassurance, then he'd start over-analyzing every symptom he had and recalculating doses, and—
All it did was give him more things to freak out about when he thought about it too hard.
Especially if it spiraled into thinking about how he got into this situation in the first place.
Or how many other people went hungry while he was still in a coma traveling near light-speed, while he was bumbling around recovering from amnesia, while he and Rocky messed around in the Tau Ceti system and got to know each other, while the beetles were still making their way back, if they even make it back at all—
I didn't agree to any of this, I didn't ask to be responsible for them, I didn’t ask to die in space—
Grace groans and pulls his head back from the microscope, squeezing his eyes shut. He shoves his hands under his glasses to dig his fingers into his orbital sockets, willing the sharp pain behind his eyes to abate just a little so that he can focus on the Taumoeba for a little while longer.
When that doesn't work, he stands abruptly and shucks off his lab coat, draping it across the back of his chair.
Grace follows the quick-exit decontamination protocol and steps through the inner door, leaning back against it as his hair gets ruffled by a blast of nitrogen in the mini-airlock. It's sucked back out and replaced with normal ship air just as quickly with a familiar woosh-hiss.
The outer door slides open to reveal the rest of the lab. Dark and quiet.
He pulls down his glasses and stares at the cupola window on the opposite side, trying to give his eyes a break.
Humans designated the main star in this system 40 Eridani A, but it also had a formal name... Keid.
Keid wasn't in view on this side of the ship, since they were currently decelerating towards it derriere-first. But Grace could see the star's two smaller companions, 40 Eridani B and C. Eventually they'd move on to a different part of their orbit, but they were far enough away to stay visible for a good long while and had been keeping him company for the last few weeks. It gave Grace something convenient to focus on whenever his eyes started aching.
He'd also been trying to think of better names for them.
They were bigger and brighter than any of the stars around them: A bright blue-white dwarf and its dimmer red-gold mate, quietly dancing and switching sides every few days as they orbited their primary star together. Everything in the window was stationary to the naked human eye, but Grace liked to check on them, track their progress across the days and weeks, picture their movement in his mind like a stop-motion animation.
Most things in space look stationary from a human perspective, no matter how fast your ship is flying, because everything is so unfathomably far away. Grace could obviously feel the 1.5G from the deceleration, but there was no other indication that the Hail Mary was moving or changing speeds at all.
At least until Mary piped up about a new "Blip A" on her radar.
Grace sighed and put his glasses back on, pushing away from the door and taking a heavy step towards the ladder.
Mary had thrown a handful of proximity alarms while on route to Erid. The radar blips were usually just asteroids or some other category of space rock (in one notable instance, a particularly thick cloud of magnetic gases), but Grace still had to go in the cockpit to verify, silence the alarm, and adjust their course if needed.
It was probably for the best, in this case. He wasn't going to make much more progress in the lab if he was already winded just from climbing a ladder.
Rocky was due to wake up shortly and would probably insist that Grace sleep next.
~Grace must reserve energy~ He'd say, an anxious tone underlying the musical chords of the now-familiar phrase.
Energy. Their lives currently revolved around it. Nutrients. Taumoeba. Calories. Astrophage. If only he could safely eat and digest Astrophage, or absorb energy directly from the stars like they could. Like plants could. That would be ideal, honestly.
He was daydreaming about sunning himself on a warm palm tree island somewhere (and maybe eating out of a cornucopia full of tropical fruits) when he topped the ladder and lazily rolled into the cockpit, dramatically splaying all his limbs out on the floor and letting out a dramatic sigh.
He pushed himself up onto his feet, grunting in a very manly way (thank you very much), and plonked down into the pilot chair so he could check the radar.
"Pilot detected."
"Yup. Thank you, Mary."
The bright radar ping was still a pretty good distance away, just like the original Blip A had been at first. Grace tapped a few screens and menus to get a little more information about it.
It wasn't very big and wasn't changing course, so it probably wasn't another Eridian spaceship. Bummer.
Grace decided it was probably an asteroid, but the signature looked kind of weird compared to what they'd encountered before and its dimensions didn't match any of the known celestial objects that the Eridians had mapped before they left.
Although that was about 50 years ago, now.
He checked their trajectory first to confirm they weren't on a crash course, then scribbled some math on his arm to figure how much time they had before the Hail Mary passed it. Rocky was nearing the end of a long rest period, and according to Grace's estimates (he kept a chart), his best friend should be up within a few hours. Grace wanted his opinion about the mystery object and he didn't want to alter their course or speed without Rocky being on board (so to speak).
Hail Mary had already slowed significantly, but she was scheduled to continue decelerating for a couple of days until she reached a safe orbital speed. Then they only had a few weeks to meet up with Threeworld and catch a ride.
When Grace did the original navigation calculations for Rocky, the Blip A would have arrived when Erid was on the near side of the solar system. This would have been perfect, as he wanted to dock there first to reunite with his people and his mate, sing the good news about Taumoeba, then maybe assist with a second mission to release Taumoeba 82.5 into Threeworld's atmosphere. Even if it was a relatively safe mission for a crew (no fishing required), it didn't make sense for him to attempt it alone.
But then Blip A lost all her fuel and power, leaving Rocky stranded. And then it took a while for Grace to locate him. And most importantly, Hail Mary was much smaller and had a completely different acceleration rate.
Grace had to redo all of the navigation calculations from scratch. This time, Erid would be on the opposite side of the star system when they arrived. Sure, they got there faster than the Blip A would have, but the circumnavigation required to get around the star would still add to their total travel time.
After mulling it over for a long time (and doing a lot of math), Rocky and Grace decided it was worth it to visit Threeworld first.
Threeworld had a pretty tight orbit and was moving quick, but it would be coming around the far side of the star towards them as they finished their approach. Once they reached orbital speed, they planned to change course and fly straight to a calculated rendezvous zone, where they would meet up with the planet and drop into orbit. Bam, they've hitched a free ride to the other side of the star!
Since they won't be driving, they'll have plenty of time (and the necessary Eridian/man-power) to seed the planet with a healthy dose of Taumoeba to kick-start its new ecosystem. If everything goes to plan, the star will already be a little brighter and warmer by the time Rocky gets his well-deserved hero's welcome. If the introduction went really well, the Eridians might not even need a follow-up mission.
On the far side of the star, Threeworld will catch up to the slower-moving Erid (which was NOT in the typical habitable zone, thank you very much). A quick orbital slingshot and flash of the Hail Mary's spin drives at close approach, and they'd suddenly be in the final stretch — and a lot closer to Erid than they started.
However, the planet wouldn't exactly wait around for them to arrive if they were late. Kind of like the buses in San Francisco. If they missed it, they'd be flying on their own fuel, coming home a few weeks later, and feeling a bit less accomplished.
But a few extra weeks for Grace might mean the difference between full recovery and developing a life-long condition. So he wasn't going to be taking any chances.
Grace finished his math and flitted his eyes over the formulas, checking for errors. The result had him pretty confident that Rocky would wake up before it was too late to check out the anomalous blip. Satisfied, he acknowledged the alert and silenced it for the next six hours. Mary would only re-alert him if something new appeared or the blip suddenly changed trajectory or speed.
Grace flopped back in the pilot chair and looked over at the window in the side of the cockpit. It pointed in the same direction as the cupola downstairs, and Grace found himself staring at the binary stars again. The odd pair. The dancing couple.
As far as Grace knew, they were reflecting off the retinas of the only creature who could sense light within about 15 light years.
It had been a long journey through the vastness of space. Piercing through a light dusting of interstellar medium in almost total darkness. Only a few sparks of light had been visible there — whatever dim wavelengths made it through the remnant gases of ancient nebulae.
It was kind of funny that the team back on earth had been worried that 3-5 years of interstellar travel in close quarters would drive humans crazy. Always the contrarian, Grace was secretly happy to prove them wrong. He sometimes felt like Rocky's presence was the only thing keeping him sane.
Whenever Rocky slept, especially for this long, Grace missed him like he'd miss his heart if it left his chest.
It'd be nice to have another person to talk to when Rocky's asleep, but...
He expelled air, making weird noises as he shook his head and let the motion carry into his limbs, windmilling his arms, doing his best to get the blood flowing and wake up a bit. He swung down onto the ladder to drop back down into the lab.
He needed to finish up in the lab, grab his favorite laptop, and hang out in the dormitory. For no particular reason.
Rocky hated waking up in an empty room.