The Cat Who Walked Through Walls

by Robert A. Heinlein

  There is another way to land. Stop dead right over the spot where you want to touch down. Fall like a rock. Brake with your jet so precisely that you kiss the ground like a juggler catching an egg on a plate.

  One minor difficulty- Right-angled turns are about the most no-good piloting one can do. You waste delta vee something scandalous-your boat probably doesn't carry that much fuel. ("Delta vee"-pilot's jargon for "change in velocity" because, in equations, Greek letter delta means a fractional change and "v" stands for velocity-and please remember that "velocity" is a direction as well as a speed, which is why rocket ships don't make U-tums.)

  I set about programming into the Volvo's little pilot computer the sort of synergistic landing Armstrong and Aldrin made but one not nearly as sophisticated. Mostly I had to ask the piloting computer to call up from its read-only memory its generalized program for landing from an orbit circum Luna... and it docilely admitted that it knew how... and then I had to inject data for this particular landing, using the crib sheet supplied by Budget Jets.

  Finished with that, I told the computer pilot to check what I had entered; it reluctantly conceded that it had all it needed to land at Hong Kong Luna at twenty-two hundred hours seventeen minutes forty-eight point three seconds.

  Its clock read 1957. Just twenty hours ago a stranger calling himself "Enrico Schultz" had sat down uninvited at my table in Rainbow's End-and five minutes later he was shot. Since then, Gwen and I had wed, been evicted, "adopted" a useless dependent, been charged with murder, and run for our lives. A busy day!-and not yet over.

  I had been living in humdrum safety much too long. Nothing gives life more zest than running for your life. "Copilot."

  "Copilot aye aye!"

  "This is fun! Thank you for marrying me."

  "Roger, Captain darling! Me, too!"

  This was my lucky day, no doubt about it! A lucky break in the timing had kept us alive. At this instant Chief Franco must be checking every passenger entering the twenty o'clock shuttle, waiting for Dr. Ames and Mistress Novak to claim their reservations-while we were already out the side door. But, while that critical tuning saved our lives. Lady Luck was still handing out door prizes.

  How? From Golden Rule's orbit our easiest landing on Luna would involve putting down at some point on the terminator- least fuel consumed, smallest delta vee. Why? Because we were already on that terminator line, going pole to pole, south to north, north to south, so our simplest landing was to bend it down where we were, never change our heading.

  To land in the east-west direction would involve throwing away our present motion, then expending still more delta vee making that foolish right-angle turn-then programming for landing. Maybe your bank account can afford this waste; your skycar cannot-you're going to find yourself sitting up there with no fuel and nothing under you but vacuum and rocks. Unappetizing.

  To save our necks I was happy to accept any landing field on Luna... but that door prize from Lady Luck included landing at my preferred field (Hong Kong Luna) just about daybreak there, with only an hour spent parked in orbit waiting for the time to tell the computer pilot to take us down. What more could I ask for?

  At that moment we were floating over the backside of the Moon-as corrugated as the backside of an alligator. Amateur pilots do not land on the far side of Luna for two reasons: 1) mountains-the side of the Moon turned away from Earth makes the Alps look like Kansas; 2) settlements-there aren't any to speak of. And let's not speak of settlements that aren't to speak of, because it might make some unspeakable settlers quite angry.

  In another forty minutes we would be over Hong Kong Luna just as sunrise was reaching it. Before that time I would ask for clearance to land and for ground control on the last and touchiest part of landing-then spend the next two hours in going around behind again and gently lowering the Volvo down for landing. Then it would be time to turn control over to Hong Kong Luna ground control but, I promised myself, I would stay on overrides and work the landing myself, just for drill. How long had it been since I had shot an airless landing myself? Calhsto, was it? What year was that? Too long!

  At 2012 we passed over Luna's north pole and were treated to earthrise... a breathtaking sight no matter how many times one has seen it. Mother Earth was in half phase (since we were ourselves on Luna's terminator) with the lighted half to our left. It being only days past summer solstice, the north polar cap was tilted into full sunlight, dazzling bright. But North America was almost as bright, being heavily cloud-covered except part of the Mexican west coast.

  I found that I was holding my breath, and Gwen was squeezing my hand. I almost forgot to call HKL ground control.

  "Volvo Bee Jay Seventeen calling HKL Control. Do you read me?"

  "Bee Jay Seventeen affirm. Go ahead."

  "Request clearance to land approx twenty-two hundred seventeen forty-eight. Request ground-controlled landing with manual override. I am out of Golden Rule and still in Golden Rule orbit approx six klicks west of her. Over."

  "Volvo Bee Jay Seventeen. Cleared to land Hong Kong Luna approx twenty-two seventeen forty-eight. Shift to satellite channel thirteen not later than twenty-one forty-nine and be ready to accept ground control. Warning: You must start standard descent program that orbit at twenty-one oh-six nineteen and follow it exactly. If at insertion for ground-controlled landing you are off in vector three percent or in altitude four klicks, expect wave off. Control HKL."

  "Roger wilco." I added, "I'll bet you don't realize that you are talking to Captain Midnight, the Solar System's hottest pilot"-but I shut off the mike before I said it.

  Or so I thought. I heard a reply, "And this is Captain Hem-orrhoid Hives, Luna's nastiest ground-control pilot. You're going to buy me a liter of Glenlivet after I bring you down. If I bring you down."

  I checked that microphone switch-didn't seem to be anything wrong with it. I decided not to acknowledge. Everybody knows that telepathy works best in a vacuum... but there ought to be some way for an ordinary Joe to protect himself against supermen.

  (Such as knowing when to keep his mouth shut.) I set the alarm for twenty-one hours, then processed to attitude straight down and, for the next hour, enjoyed the ride while holding hands with my bride. The incredible mountains of the Moon, taller and sharper than the Himalayas and tragically desolate, flowed by ahead of (under) us. The only sound was the soft murmur of the computer and the sighing of the air scavenger-and a regular, annoying sniff from Bill. I shut out all sound and invited my soul. Neither Gwen nor I felt like talking. It was a happy interlude, as peaceful as the Old Mill Stream.

  "Richard! Wake up!"

  "Huh? I wasn't asleep."

  "Yes, dear. It's past twenty-one.**

  Uh... so it was. Twenty-one oh-one and ticking. What happened to the alarm? Never mind that now-I had five minutes and zip seconds to make sure we entered descent program on time. I hit the control to process, from headstand to bel-lywhopper backwards-easiest for descent, although supine backwards will work just as well. Or even sideways backwards. Whichever, the jet nozzle must point against the direction of motion in order to reduce speed for insertion into landing program-i.e., "backwards" for the pilot, like me Fillyloo Bird. (But I'm happiest when the horizon looks "right" for the way I'm belted in; that's why I prefer to put the skycar into bel-lywhopper backwards.)

  As soon as I felt the Volvo start to process I asked the computer if it was ready to start landing program, using standard code from the list etched on its shell.

  No answer. Blank screen. No sound.

  I spoke disparagingly of its ancestry. Gwen said, "Did you punch the execute button?"

  "Certainly I did!" I answered and punched it again.

  Its screen lit up and the sound came on at teeth-jarring level:

  "How do you spell comfort? For the wise Luna citizen today, overworked, overstimulated, overstressed, it is spelled C, 0, M, F, I, E, S-that's Comfies, the comfort therapists recommend most for acid stomach, heartburn, gastric ulcers,
bowel spasm, and simple tummy ache. Comfies! They Do More! Manufactured by Tiger Balm Pharmaceuticals, Hong Kong Luna, makers of medicines you can rely on. C, 0, M, F, I, E, S, Comfies! They Do More! Ask your therapist." Some screech owls started singing about the delights of Comfies.

  "This damn thing won't turn off!"

  "Hit it!"

  "Huh?"

  "Hit it, Richard."

  I could not see any logic in that but it did meet my emotional needs; I slapped it, fairly hard. It continued to spout inanities about over-priced baking soda.

  "Dear, you have to hit it harder than that. Electrons are timid little things but notional; you have to let them know who's boss. Here, let me." Gwen walloped it a good one-I thought she would crack the shell.

  It promptly displayed:

  Ready for descent-Zero Time = 21-06-17.0.

  Its clock showed 21-05-42.7

  -which gave me just time to glance at the altimeter radar (which showed 298 klicks above ground, steady) and at the doppler readout, which showed us oriented along our motion-over-ground line, close enough for government work... although what I could have done about it in ca. ten seconds I do not know. Instead of using fractional jets paired in couples to control attitude, a Volvo uses gyros and processes against them- cheaper than twelve small jets and a mess of plumbing. But slower.

  Then, all at once, the clock matched the zero time, the jet cut in, shoving us into the cushions, and the screen displayed the program of bums-the topmost being: 21-06-17.0- -19 seconds 21-06-36.0

  Sweet as could be, the jet cut off after nineteen seconds without even clearing its throat. "See?" said Gwen. "You just have to be firm with it."

  "I don't believe in animism."

  "You don't? How do you cope with- Sorry, dear. Never mind; Gwen will take care of such things."

  Captain Midnight made no answer. You couldn't truthfully say that I sulked. But, damn it all, animism is sheer superstition. (Except about weapons.)

  I had shifted to channel thirteen and we were just coming up on the fifth bum. I was getting ready to turn control over to HKL GCL (Captain Hives) when that dear little electronic idiot crashed its RAM-its Random Access Memory on which was written our descent program. The table of bums on the screen dimmed, quivered, shrank to a dot and disappeared. Frantically I punched the reset key-nothing happened.

  Captain Midnight, undaunted as usual, knew just what to do. "Gwen! It lost the program!"

  She reached over and clouted it. The bum schedule was not restored-a RAM, once crashed, is gone forever, like a burst soap bubble-but it did boot up again. A cursor appeared in the upper left comer of the screen and blinked inquiringly. Gwen said, "What time is your next bum, dear? And how long?"

  'Twenty-one, forty-seven, seventeen, I think, for, uh, eleven seconds. I'm fairly sure it was eleven seconds."

  "I check you on both figures. So do that one by hand, then ask it to recompute what it lost."

  "Righto." I typed in the bum. "After this one I'm ready to accept control from Hong Kong."

  "So we're out of the woods, dear-one bum by hand and then ground control takes over. But we'll recompute just for insurance."

  She sounded more optimistic than I felt. I could not remember what vector and altitude I was supposed to achieve for take-over by ground control. But I had no time to worry about it; I had to set up this bum.

  I typed it in: 21-47-17.0- -11.0 seconds 21-47-28.0

  I watched the clock and counted with it. At exactly seventeen seconds past 2147 I jabbed the firing button, held it down. The jet fired. I don't know whether I fired it or the computer did. I held my finger down as the seconds ticked off and lifted it exactly on eleven seconds.

  The jet kept on firing.

  ("-run in circles, scream and shout!") I wiggled the firing button. No, it was not stuck. I slapped the shell. The jet kept on roaring and shoving us into the cushions.

  Gwen reached over and cut power to the computer. The jet stopped abruptly.

  I tried to stop trembling. "Thank you, Copilot."

  "Yessir."

  I looked out, decided that the ground seemed closer than I liked, so I checked the altimeter radar. Ninety something-the third figure was changing. "Gwen, I don't think we're going to Hong Kong Luna."

  "I don't think so, either."

  "So now the problem is to get this junk out of the sky without cracking it."

  "I agree, sir."

  "So where are we? An educated guess, I mean. I don't expect miracles." The stuff ahead-behind, rather; we were still oriented for braking-looked as rough as the back side. Not a place for an emergency landing.

  Gwen said, "Could we face around the other way? If we could see Golden Rule, that would tell us something."

  "Okay. Let's see if it responds." I clutched the processing control, told the skycar to swing one-eighty degrees, passing through headstand again. The ground was noticeably closer. Our skycar settled down with the horizon running right and left-but with the sky on the "down" side. Annoying... but all we wanted was to look for our late home. Golden Rule habitat. "Do you see it?"

  "No, I don't, Richard."

  "It must be over the horizon, somewhere. Not surprising, it was pretty far away the last time we looked-and that last bum was a foul blast. A long one. So where are we?"

  "When we swung past that big crater- Aristoteles?"

  "Not Plato?"

  "No, sir. Plato would be west of our track and still in shadow.

  It could be some ringwall I don't know... but that smooth stuff-that fairly smooth stuff-south of us makes me think that it must be Aristoteles."

  "Gwen, it doesn't matter what it is; I've got to try to put this wagon down on that smooth stuff. That fairly smooth stuff. Unless you have a better idea?"

  "No, sir, I do not. We're falling. If we speeded up enough to maintain a circular orbit at this altitude, we probably would not have enough fuel to bring her down later. That's a guess."

  I looked at the fuel gauge-that last long, foul blast had wasted a lot of my available delta vee. No elbow room. "I think your guess is a certainty-so we'll land. We'll see if our little friend can calculate a parabolic descent for this altitude- for I intend to kill our forward speed and simply let her drop, once we are over ground that looks smooth. What do you think?"

  "Uh, I hope we have fuel enough."

  "So do I. Gwen?"

  "Yes, sir?"

  "Honey girl, it's been fun."

  "Oh, Richard! Yes."

  Bill said in a choked voice, "Uh, I don't think I can-"

  I was processing to put us back into a braking attitude. "Pipe down. Bill; we're busy!" Altimeter showed eighty something- how long did it take to fall eighty klicks in a one-sixth gee field? Switch on the pilot computer again and ask it? Or do it in my head? Could I trust the pilot computer not to switch on the jet again if I fed it juice?

  Better not risk it. Would a straight-line approximation tell me anything? Let's see- Distance equals one half acceleration multiplied by the square of the time, all in centimeters and seconds. So eighty klicks is, uh, eighty thousand, no, eight hund- No, eight million centimeters. Was that right?

  One-sixth gee- No, half of one sixty-two. So bring it across and take the square root-

  One hundred seconds? "Gwen, how long till impact?"

  "About seventeen minutes. That's rough; I just rounded it off in my head."

  I took another quick look inside my skull, saw that in failing to allow for forward vector-the "fall-around" factor-my

  "approximation" wasn't even a wild guess. "Close enough. Watch the doppler; I'm going to kill some forward motion. Don't let me kill all of it; we'll need some choice in where to put down."

  "Aye, aye. Skipper!"

  I switched power to the computer; the jet immediately fired. I let it run five seconds, cut power. The jet sobbed and quit. "That," I said bitterly, "is one hell of a way to handle the throttle. Gwen?"

  "Just crawling along now. Can we swing and see where
we're going?"

  "Sure thing."

  "Senator-"

  "Bill-shut up!" I tilted it around another hundred and eighty degrees. "See a nice smooth pasture ahead?"

  "It all looks smooth, Richard, but we're still almost seventy klicks high. Should get down pretty close before you kill all your forward speed, maybe? So you can see any rocks."

  "Reasonable. How close?"

  "Uh, how does one klick sound?"

  "Sounds close enough to hear the wings of the Angel of Death. How many seconds till impact? For one-kilometer height, I mean."

  "Uh, square root of twelve hundred plus. Call it thirty-five seconds."

  "All right. You keep watching height and terrain. At about two klicks I want to start to kill the forward speed. I've got to have time to twist another ninety degrees after that, to back down tail first. Gwen, we should have stayed in bed."

  "I tried to tell you that, sir. But I have faith in you."

  "What is faith without works? I wish I was in Paducah. Time?"

  "Six minutes, about."

  "Senator-"

  "Bill, shut up! Shall we trim off half me remaining speed?"

  "Three seconds?"

  I gave a three-second blast, using the same silly method of starting and stopping the jet.

  'Two minutes, sir."

  "Watch the doppler. Call it." I started the jet.

  "Now!"

  I stopped it abruptly and started to process, tail down, "windshield" up. "How does it read?"

  "We're as near dead in the water as can be done that way, I think. And I wouldn't fiddle with it; look at that fuel reading."

  I looked and didn't like it. "All right, I don't blast at all until we are mighty close." We steadied in the heads-up attitude-nothing but sky in front of us. Over my left shoulder I could see the ground at about a forty-five-degree angle. By looking past Gwen I could see it out the starboard side, too, but at quite a distance-a bad angle, useless. "Gwen, how long is this buggy?"