Heinlein, Robert A – Have Space Suit will Travel

But ten minutes later I was handling myself fairly well and in half an hour I felt as if I had worn one all my life. The distributed weight wasn’t too great (and I knew it wouldn’t amount to much on the Moon). The joints were just a case of getting used to more effort. I had had more trouble learning to swim.

It was a blistering day: I went outside and looked at the Sun. The polarizer cut the glare and I was able to look at it. I looked away; polarizing eased off and I could see around me.

I stayed cool. The air, cooled by semi-adiabatic expansion (it said in the manual), cooled my head and flowed on through the suit, washing away body heat and used air through the exhaust valves. The manual said that heating elements rarely cut in, since the usual problem was to get rid of heat; I decided to get dry ice and force a test of thermostat and heater.

I tried everything I could think of. A creek runs back of our place and beyond is a pasture. I sloshed through the stream, lost my footing and fell -the worst trouble was that I could never see where I was putting my feet. Once I was down I lay there a while, half floating but mostly covered. I didn’t get wet, I didn’t get hot, I didn’t get cold, and my breathing was as easy as ever even though water shimmered over my helmet.

I scrambled heavily up the bank and fell again, striking my helmet against a rock. No damage, Oscar was built to take it. I pulled my knees under me, got up, and crossed the pasture, stumbling on rough ground but not falling. There was a haystack there and I dug into it until I was buried.

Cool fresh air … no trouble, no sweat.

After three hours I took it off. The suit had relief arrangements like any pilot’s outfit but I hadn’t rigged it yet, so I had come out before my air was gone. When I hung it in the rack I had built, I patted the shoulder yoke. “Oscar, you’re all right,” I told it. “You and I are partners. We’re going places.” I would have sneered at five thousand dollars for Oscar.

While Oscar was taking his pressure tests I worked on his electrical and electronic gear. I didn’t bother with a radar target or beacon; the first is childishly simple, the second is fiendishly expensive. But I did want radio for the space-operations band of the spectrum-the antennas suited only those wavelengths. I could have built an ordinary walkie-talkie and hung it outside-but I would have been kidding myself with a wrong frequency and gear that might not stand vacuum. Changes in pressure and temperature and humidity do funny things to electronic circuits; that is why the radio was housed inside the helmet.

The manual gave circuit diagrams, so I got busy. The audio and modulating circuits were no problem, just battery-operated transistor circuitry which I could make plenty small enough. But the microwave part- It was a two-headed calf, each with transmitter and receiver-one centimeter wavelength for the horn and three octaves lower at eight centimeters for the spike in a harmonic relationship, one crystal controlling both. This gave more signal on broadcast and better aiming when squirting out the horn and also meant that only part of the rig had to be switched in changing antennas. The output of a variable-frequency oscillator was added to the crystal frequency in tuning the receiver. The circuitry was simple-on paper.

But microwave circuitry is never easy; it takes precision machining and a slip of a tool can foul up the impedance and ruin a mathematically calculated resonance.

Well, I tried. Synthetic precision crystals are cheap from surplus houses and some transistors and other components I could vandalize from my own gear. And I made it work, after the fussiest pray-and-try-again I have ever done. But the consarned thing simply would not fit into the helmet.

Call it a moral victory-I’ve never done better work.

I finally bought one, precision made and embedded in plastic, from the same firm that sold me the crystal. Like the suit it was made for, it was obsolete and I paid a price so low that I merely screamed. By then I would have mortgaged my soul-I wanted that suit to work.