Okay.
I see how it is.
Iโm not some intrepid explorer who nobly sacri๏ฌced his life to save Earth. Iโm a terri๏ฌed man who had to be literally dragged kicking and screaming onto the mission.
Iโm a coward.
All that came to me in aย ๏ฌash. I sit on the stool and stare at the lab table. I went from nearly hysterical toโฆthis. This is worse. Iโm numb.
Iโm a coward.
Iโve known for a while that Iโm not the best hope for saving mankind. Iโm just a guy with the genes to survive a coma. I made my peace with that a while ago.
But I didnโt know I was a coward.
I remember the emotions. I remember that feeling of panic. I remember it all now. Sheer, unadulterated terror. Not for Earth or humanity or the children. For myself. Utter panic.
โGod damn you, Stratt,โย I mumble.
What ticks me o๏ฌย the most is that she was right. Her plan worked perfectly. I got my memory back, and now Iโm so committed to the mission Iโm still going to give it my all. Plus, come on, of course I was going to give it my all. What else would I do? Let 7 billion people die to spite Stratt?
At some point, Rocky came through his tunnel to the lab. I donโt know how long heโs been there. He didnโt have to comeโhe couldย โseeโย everything going on from the control room with his sonar sense. Still, there he is.
โYou are very sad,โย he says.ย โYeah.โ
โI am sad also. But we not be sad for long. You are scientist. I am engineer.
Together we solve.โ
I throw up my arms in frustration.ย โHow?!โ
He clicked along the tunnel to the closest point above me.ย โTaumoeba eat all your fuel. Therefore Taumoeba survive and breed in fuel-tank environment.โ
โSo?โ
โMost life no can live outside its air. I die if not in Erid air. You die if not in Earth air. But Taumoeba survive when not in Adrian air. Taumoeba stronger than Erid lifeโstronger than Earth life.โ
I crane my neck to look up at him.ย โTrue. And Astrophage are also pretty tough. They can live in vacuum and on the surface of stars.โ
He tapped two claws together.ย โYes yes. Astrophage and Taumoeba from same biosphere. Probably evolve from common ancestor. Adrian life is very strong.โ
I sit up.ย โYeah. Okay.โ
โYou have idea already. Not question. I know you. You have idea already.
Tell idea.โ
I sigh.ย โWellโฆVenus, Threeworld, and Adrian all have a bunch of carbon dioxide. The Astrophage breeding zone in all three is where pressure is 0.02 atmospheres. So maybe Iโll start with a chamber full of pure carbon dioxide at
0.02 atmospheres and see if Taumoeba survives that. Then add in more gases one at a time to see what the problem is.โ
โUnderstand,โย says Rocky.
I get to my feet and dust o๏ฌย my jumpsuit.ย โI need you to make me a test chamber. Clear xenonite with valves so I can let air in and out. Also, I need to be able to set temperature to minus 100 degrees Celsius, minus 50 degrees Celsius, or minus 82 degrees Celsius.โ
I could use my own equipment, but why not take advantage of superior material and craftsmanship?
โYes yes. I make now. We are team. Weย ๏ฌx this. No be sad.โย He skitters down the tunnel toward the dormitory.
I check my watch.ย โThe main thrust ends in thirty-four minutes. After thatโs done, letโs use the beetles to put ourselves in centrifuge mode.โ
Rocky pauses.ย โDangerous.โ
โYeah, I know. But we need gravity for the lab and I donโt want to wait eleven days. I want to make good use of time.โ
โBeetles arranged for thrust, not rotation.โ
Itโs true. Our propulsion right now is, to say the least, rudimentary. We donโt have servos or gimbals to vector our thrust. Weโre like a sixteenth- century nautical ship, but weโre using beetles for sails. Actually, scratch that. The nautical ship could at least control the angle of their sails. Weโre more like a paddlewheel boat with a broken rudder.
Itโs not all bad, though. We have some slight attitude control by deciding how much each engine thrusts. Itโs how Rocky zeroed out our rotation before.ย โItโs worth the risk.โ
He skitters back up the tunnel to face me.ย โShip will rotate o๏ฌ-axis. No can unspool centrifuge cables. Would tangle.โ
โWeโll create the needed rotationย ๏ฌrst, then shut o๏ฌย beetles, then unspool cables.โ
He draws back.ย โIf ship not unspooled, force is too much for human.โ
That does present a problem. I want 1 g of gravity for the lab when the ship is fully unspooled in two halves. To get that much rotational inertia with the ship in one piece means spinning itย veryย fast. Last time we did that, I passed out in the control room and Rocky almost died saving me.
โOkayโฆโย I say.ย โHow about this: Iโll lay down in the storage room under the dormitory. Thatโs the closest to the center of ship I can get. The force will be smallest there. Iโll be okay.โ
โHow you operate centrifuge controls from storage room, question?โย โIโllโฆummโฆIโll bring the labโs control screen down there with me. Iโll run
data and power extension cables from the lab to the storage room. Yeah. That
should work.โ
โWhat if you unconscious and no can operate controls, question?โ
โThen you cancel the rotation and Iโll wake up.โ
He shimmies back and forth.ย โNo like. Alternate plan: Wait eleven days. Get to my ship. Clean out you ship fuel tanks. Sterilizeโmake sure no Taumoeba. Re๏ฌll with fuel from my ship. Then can use all functions of you ship again.โ
I shake my head.ย โI donโt want to wait eleven days. I want to work now.โย โWhy, question? Why no wait, question?โ
Heโs completely right, of course. Iโm risking my life and maybe the
structural integrity of theย Hail Mary. But I canโt just sit around for eleven days when thereโs so much work to do. How do I explainย โimpatienceโย to someone who lives seven hundred years?
โHuman thing,โย I say.
โUnderstand. Not actually understand, butโฆunderstand.โ
โ
The spin-up went as planned. Rocky selected Ringo to do the spinning work, leaving John and Paul o๏ฌine. George is still safely aboard the ship in case I need him.
The g-forces during the spin-up were roughโI wonโt lie. But I stayed awake long enough to manually deal with the centrifuge steps. Iโm getting pretty good at it now. Since then, itโs been a nice, level 1 g.
Yeah, it was impatient and a little risky, but thanks to that, Iโve had seven days of hardcore science since then.
Rocky delivered on the testing apparatus as promised. As always, everything workedย ๏ฌawlessly. Instead of a small, annoying glass vacuum chamber, I had something resembling a largeย ๏ฌsh tank. Xenonite doesnโt care if thereโs a bunch of air pressure on a large,ย ๏ฌat panel.ย โBring it on,โย says xenonite.
I have, shall we say, an inexhaustible supply of Taumoeba. Theย Hail Maryย is currently the Taumoeba party bus. All I have to do is open the fuel line that used to lead to the generator when I want more.
โ
โHey, Rocky!โย I call out from the lab.ย โWatch me pull a Taumoeba out of a hat!โ
Rocky climbs up his tunnel from the control room.ย โI assume that is Earth idiom.โ
โYeah. Earth has entertainment calledย โtelevisionโย andโโย โDo not explain, please. You haveย ๏ฌndings, question?โ
Just as well. It would take a long time to explain cartoons to an alien.ย โI
have some results.โ
โGood good.โย He hunkers down into a comfortable sitting position.ย โTellย ๏ฌndings!โย He tries to hide it, but his voice is just a touch higher in pitch than normal.
I gesture to the lab apparatus.ย โThis functions perfectly, by the way.โย โThank. Tell aboutย ๏ฌndings.โ
โMyย ๏ฌrst experiment was Adrianโs environment. I added Taumoeba and a
slide covered in Astrophage. The Taumoeba survived and ate it all. No surprise there.โ
โNo surprise. Is their native environment. But proves equipment works.โย โExactly. I did more tests to learn Taumoebaโs limits. In Adrian air, they
can live from minus 180 degrees Celsius to 107 degrees Celsius. Outside that
range they die.โย โImpressive range.โ
โYes. Also, they can survive in a near vacuum.โ
โLike your fuel tanks.โ
โYeah, but not aย totalย vacuum.โย I frown.ย โThey need carbon dioxide. At least a little bit of it. I made an Adrian environment but put argon in instead of carbon dioxide. The Taumoeba didnโt eat anything. They stayed dormant. Eventually they starved to death.โ
โExpected,โย he says.ย โAstrophage need carbon dioxide. Taumoeba from same ecology. Taumoeba also need carbon dioxide. How they get carbon dioxide in fuel tanks, question?โ
โI had the same question!โย I say.ย โSo I did a spectrograph of my fuel-bay sludge. Thereโs a bunch of CO2ย gas dissolved into the liquid.โ
โAstrophage probably have carbon dioxide inside. Or decomposition creates carbon dioxide. Some percentage died in fuel tanks over time. Not all cells are perfect. Defects. Mutations. Some die. Those dead Astrophage put carbon dioxide in tanks.โ
โAgreed.โ
โGoodย ๏ฌndings,โย he says. He starts climbing back down.ย โWait. I have more. Much more.โ
He stops.ย โMore, question? Good.โ
I lean against my lab table and pat the tank.ย โI made Venus in the tank. But not quite Venus. Venusโs air is 96.5 percent carbon dioxide and 3.5 percent nitrogen. I started with just the carbon dioxide. The Taumoeba wereย ๏ฌne. Then I added the nitrogen. And the Taumoeba all died.โ
He raises his carapace.ย โAll die, question? Sudden, question?โย โYes,โย I say.ย โIn seconds. All dead.โย โNitrogenโฆunexpected.โ
โYeah, very unexpected!โย I say.ย โI repeated experiment with Threeworldโs air. Carbon dioxide only: The Taumoeba wereย ๏ฌne. I added in the sulfur dioxide: The Taumoeba wereย ๏ฌne. I added the nitrogen: Boom! All the Taumoeba died.โ
He taps a claw absently on the tunnel wall.ย โVery very unexpected. Nitrogen harmless to Erid life. Nitrogen required by many Erid life.โ
โSame with Earth,โย I say.ย โEarthโs air is seventy-eight percent nitrogen.โย โConfusing,โย he says.
Heโs not alone. Iโm just as ba๏ฌed as he is. Weโre both thinking the same
thing: If all life evolved from a single source, how can nitrogen be critical to two biospheres and toxic to a third?
Nitrogen is utterly harmless and nearly inert in its gaseous state. Itโs usually content to be N2, which barely wants to react with anything. Human bodies ignore the stu๏ฌย despite every breath being 78 percent nitrogen. As for Erid,
their atmosphere is mostly ammoniaโa nitrogen compound. How could a
panspermia event ever seed Earth and Eridโtwo nitrogen-riddled planetsโif a tiny amount of nitrogen kills that life?
Well, the answer to that is easy: Whatever the life-form was that caused the panspermia, it didnโt have a problem with nitrogen. Taumoeba, which evolved later, does.
Rockyโs carapace sinks.ย โSituation bad. Threeworld air is eight percent nitrogen.โ
I sit on the lab stool and cross my arms.ย โVenusโs air is 3.5 percent nitrogen. Same problem.โ
He sinks farther and his voice drops an octave.ย โHopeless. Cannot change Threeworld air. Cannot change Venus air. Cannot change Taumoeba. Hopeless.โ
โWell,โย I say.ย โWe canโt change Threeworld or Venusโs air. But maybe we can change Taumoeba.โ
โHow, question?โ
I grab my tablet from the workbench and scroll through my notes about Eridian physiology.ย โDo Eridians have diseases? Sicknesses inside your bodies?โ
โSome. Very, very bad.โ
โHow does your body kill diseases?โ
โEridian body is closed,โย he explains.ย โOnly opening happen when eat or lay egg. After opening seals, area inside made very hot inside with hot blood for long time. Kill any disease. Disease can only get into body through wound. Then is very bad. Body shut down infected area. Heat with hot blood to kill disease. If disease fast, Eridian die.โ
No immune system at all. Just heat. Well, why not? The hot circulatory system of an Eridian boils water to make the muscles move. Why not use it to cook and sterilize incoming food too? And with heavy oxidesโbasically rocksโas skin, they donโt get many cuts or abrasions. Even their lungs donโt exchange material with the outside. If any pathogens do get in, the body seals the area o๏ฌย and boils it. An Eridian body is a nearly impenetrable fortress.
But a human body is more like a borderless police state.
โHumans are very di๏ฌerent,โย I say.ย โWe get diseases all the time. We have very powerful immune systems. Also, weย ๏ฌnd cures for diseases in nature. The word isย โantibiotics.โ โ
โNo understand,โย he says.ย โCures for diseases in nature, question? How, question?โ
โOther life on Earth evolved defenses against the same diseases. They emit chemicals that kill the disease without harming other cells. Humans eat those chemicals and they kill disease but not our human cells.โ
โAmaze. Erid no have this.โ
โItโs not a perfect system, though,โย I say.ย โAntibiotics work very well atย ๏ฌrst, but then over the years, they become less and less e๏ฌective. Eventually they barely work at all.โ
โWhy, question?โ
โDiseases change. Antibiotics kill almost all the disease in the body, but some survive. By using antibiotics, humans are accidentally teaching diseases how to survive those antibiotics.โ
โAh!โย Rocky says. He raises his carapace a tad.ย โDisease evolves defense against chemical that kills it.โ
โYes,โย I say. I point at the tank.ย โNow think of Taumoeba as disease.
Think of nitrogen as antibiotic.โ
He pauses, then raises his carapace back to its proper location.ย โUnderstand! Make environment barely deadly. Breed Taumoeba that survive. Make more deadly. Breed survivors. Repeat, repeat, repeat!โ
โYes,โย I say.ย โWe donโt need to understand why or how nitrogen kills Taumoeba. We just need to breed nitrogen-resistant Taumoeba.โ
โYes!โย he says.
โGood!โย I slap the top of the tank.ย โMake me ten of these, but smaller. Also provide a way for me to get Taumoeba samples without interrupting the experiment. Make a very accurate gas injection systemโI need exact control over the nitrogen quantity in the tank.โ
โYes! I make! I make now!โ
He skitters down to the dormitory.
โ
I check the results of the spectrograph and shake my head.ย โNo good. Complete failure.โ
โSad,โย Rocky says.
I put my chin in my hands.ย โMaybe I canย ๏ฌlter out the toxins.โ
โMaybe you can concentrate on Taumoeba.โย Thereโs a special warble that Rocky does when heโs being snarky. That warble is especially present right now.
โTheyโre coming alongย ๏ฌne.โย I glance over to the Taumoeba processing tanks arrayed along one side of the lab.ย โNothing to do but wait. Weโve had good results. Theyโre already up to 0.01 percent nitrogen and surviving. The next generation might be able to go as high as 0.015.โ
โThis is waste of time. Also waste of my food.โย โI need to know if I can eat your food.โ
โEat your own food.โ
โIโve only got a few months of real food left. You have enough aboard your ship to feed a crew of twenty-three Eridians for years. Erid life and Earth life use the same proteins. Maybe I can eat your food.โ
โWhy you sayย โreal food,โย question? What is non-real food, question?โ
I checked the readout again. Why does Eridian food have so many heavy metals in it?ย โReal food is food that tastes good. Food thatโs fun to eat.โ
โYou have not-fun food, question?โ
โYeah. Coma slurry. The ship fed it to me during the trip here. I have enough to last me almost four years.โ
โEat that.โ
โIt tastes bad.โ
โFood experience not that important.โ
โHey.โย I point at him.ย โTo humans, food experience is very important.โย โHumans strange.โ
I point at the spectrometer readout screen.ย โWhy does Eridian food have
thallium in it?โย โHealthy.โ
โThallium kills humans!โ
โThen eat human food.โ
โUgh.โย I walk over to the Taumoeba tanks. Rocky had outdone himself. I can control the nitrogen content to within one part per million. And so far, things are looking good. Sure, this generation can only handle a smidgen of nitrogen, but itโs a smidgen more than the previous generation could do.
The plan is working. Our Taumoeba are developing nitrogen resistance. Will they ever be able to handle the 3.5 percent needed for Venus? Or the
8 percent for Threeworld? Who knows? Weโll just have to wait and see.
Iโm using percentages here to track the nitrogen. I can only get away with that because in all cases, Astrophage breed where the air is 0.02 atmospheres of pressure. So, since the pressure is always the same across all experiments, I can just track the percent of nitrogen.
Theย properย way to do it would be to trackย โpartial pressure.โย But thatโs annoying. Iโd just end up dividing by 0.02 atmospheres and multiplying by it again later when dealing with data.
I pat the top of Tank Three. Itโs been my lucky tank. Out of twenty-three generations of Taumoeba, Tank Three made the strongest strain nine times. Pretty good, considering sheโs got nine other tanks to compete with.
Yes, Tank Three is aย โshe.โย Donโt judge me.ย โHow long until we reach theย Blip-A?โย โSeventeen hours until reverse-thrust maneuver.โ
โOkay, letโs spin down the centrifuge now. Just in case we run into trouble and need extra time toย ๏ฌx something.โ
โAgree. I go to control room now. You go to storage locker and lieย ๏ฌat. Do not forget control panel with long extension cords.โ
I glance around the lab. Everything isย ๏ฌrmly secured.ย โYeah, okay. Letโs do it.โ
โ
โJohn, Ringo, Paul o๏ฌ,โย says Rocky.ย โVelocity is orbital.โ
There is noย โstationaryโย in a solar system. Youโre always moving around something. In this case, Rocky reduced our cruise velocity to put us in a
stable orbit about 1 AU from Tau Ceti. Thatโs where he left theย Blip-A.
Rocky relaxes in his control-room bulb. He clamps the boxes to their wall mounts. Now that the engines are o๏ฌย weโre back to zero g, and the last thing we want is for theย โmake ship thrustโย button to beย ๏ฌoating around unattended.
He grabs a couple of handholds and centers his carapace over the texture monitor. As always, it shows him my center monitor feed with colors represented as textures.
โYou in control now.โย Heโs done his job. Now itโs my turn.ย โHow long until theย ๏ฌash?โย I ask
Rocky pulls an Eridian clock o๏ฌย the wall.ย โNextย ๏ฌash is three minutes, seven seconds.โ
โOkay.โ
Rockyโs no dope. He left his ship set up to turn on its engines for a fraction of a second every twenty minutes or so, giving us a much-needed beacon. Itโs easy enough to math out where the shipย shouldย be. But gravity from other planets, inaccurate measurement of last known velocities, inaccuracies in our estimate of Tau Cetiโs gravityโฆthey all add up to make slight errors. And a slight error on the location of something orbiting a star is a pretty big distance.
So rather than hoping we can see Taulight re๏ฌect o๏ฌย the ship when we get to where it should be, he just set it up toย ๏ฌash the engines now and then. All I have to do is watch with the Petrovascope. Itโll be anย extremelyย brightย ๏ฌash.
โWhat is current nitrogen tolerance, question?โ
โTank Three had some survivors at 0.6 percent nitrogen today. Iโm breeding them up now.โ
โWhat spacing, question?โ
Itโs a conversation weโve had dozens of times. But itโs fair for him to be curious. His species depends on it.
Theย โspacing,โย as weโve come to call it, is the di๏ฌerence in how much nitrogen each of the ten tanks receives. I donโt just do the same thing in every tank. With each new generation, I try ten new percentages of nitrogen.
โIโm being aggressiveโ0.05 percent increments.โย โGood good,โย he says.
All ten tanks are breeding Taumoeba-06 (named for the nitrogen percent it can withstand). Tank One is the control, as always. It has 0.6 percent nitrogen in the air. Taumoeba-06 should have no problem in there. If it does, it means there was a mistake in the previous batch and I have to go back to an earlier strain.
Tank Two has 0.65 percent nitrogen. Tank Three has 0.7. And so on all the way up to Tank Ten with 1.05 percent. The heartiest survivors will be the champions, and will move on to the next round. I wait a few hours just to make sure they can breed for at least two generations. Taumoeba has a ridiculously fast doubling time. Fast enough to eat all my fuel in a matter of days, as it happens.
If we get to Venus or Threeworld nitrogen percentages, Iโll do much more thorough testing.
โFlash is soon,โย Rocky says.ย โCopy.โ
I bring up the Petrovascope on the center monitor. Normally, Iโd have it o๏ฌย to the side, but the center is the only one Rocky canย โsee.โย As expected, thereโs just background light in the Petrova frequency courtesy of Tau Ceti. I pan and tilt the camera. We deliberately positioned ourselves closer to Tau Ceti than theย Blip-Aย should be. So Iโm looking more or less directly away from the star. That should minimize the background IR and give me a good view of theย ๏ฌash.
โOkay. I think I have it pointed roughly toward your ship.โ
Rocky concentrates on his texture monitor.ย โUnderstand. Thirty-seven seconds untilย ๏ฌash.โ
โHey. Whatโs is your shipโs name, anyway?โย โBlip-A.โ
โNo, I mean, what do you call it?โ
โShip.โ
โYour ship has no name?โ
โWhy would ship have name, question?โย I shrugged.ย โShips have names.โ
He points to my pilotโs seat.ย โWhat is name of you chair, question?โ
โIt doesnโt have a name.โ
โWhy does ship have name but chair no have name, question?โย โNever mind. Your ship is theย Blip-A.โ
โThat is what I said. Flash in ten seconds.โย โCopy.โ
Rocky and I each fall silent and stare at our respective screens. It took me a long time to notice the subtleties, but I can now tell when Rocky is paying attention to something speci๏ฌc. He tends to angle his carapace toward it and pivot ever so slightly back and forth. If I follow the line heโs pivoting on, thatโs usually what heโs examining.
โThreeโฆtwoโฆoneโฆnow!โ
Right on cue, a few pixels on-screen blink white.ย โGot it,โย I say.
โI not notice.โ
โIt was dim. We must be far away. Hang onโฆโย I switch to the Telescope screen and pan to where theย ๏ฌash came from. I sweep back and forth with small movements until I catch a slight discoloration in the blackness. Taulight re๏ฌecting o๏ฌย theย Blip-A.ย โYeah, weโre pretty far away.โ
โBeetles have much fuel remaining. Is okay. Tell me angle change.โ
I check the readouts at the bottom of the screen. All we have to do is align theย Hail Maryย with the current telescope angle.ย โRotate yaw plus 13.72 degrees. Rotate pitch minus 9.14 degrees.โ
โYaw plus one three mark seven two. Pitch minus nine mark one four.โย He grabs the beetle controls from their holders and gets to work. Byย ๏ฌicking on and o๏ฌย the beetles in sequence, he angles the ship toward theย Blip-A.
I zero the telescope and zoom in to con๏ฌrm. The di๏ฌerence between background space and the ship is so small as to be barely perceivable. But itโs there.ย โAngle correct.โ
He focuses hard on his texture screen.ย โI no detect anything on-screen.โย โLight di๏ฌerence is very very small. Need human eyes to detect. Angle is
good.โ
โUnderstand. What is range, question?โ
I switch to the Radar screen. Nothing.ย โToo far for my radar to see. At least ten thousand kilometers.โ
โAccelerate to what velocity, question?โ
โHow aboutโฆthree kilometers per second? Will get to theย Blip-Aย in an hour or so.โ
โThree thousand meters per second. Standard acceleration rate is acceptable, question?โ
โYes. Fifteen meters per second per second.โย โTwo hundred second thrust. Begin now.โ
I brace for gravity.
