Melody Armstrong, standing on the moon's surface, watched the dials of the oxygen extractor. They had lost essential oxygen when the liftoff failed. This oxygen extractor had been one of the new devices they were to test. Now their lives depended on it working well.
The oxygen extractor operated very simply. Melody would put moon rocks into the machine. Then Hydrogen reacted with oxygen compounds in the moon rocks, producing water. Next an electric current split water into oxygen and hydrogen. Unfortunately, not all the water and hydrogen could be recovered. First some of the water stuck to the walls of the machine and to the remains of the moon rocks. Second, Hydrogen reacted with other compounds in the moon rocks. And some of the hydrogen simply leaked through the supposedly air tight joints of the machine.
Her suitphone rang. Melody smiled when she saw first the Earthlink signal, and then Grant's face on her phone monitor. "Hello,Gaunt", Melody said as she opened the connection.
"Hello, Melody. I don't have much to report on my Anti-tobacco broadcast site as yet. I have made some progress setting it up, but I'm not having any luck finding someone to program it." Grant didn't comment on Melody's use of his nickname instead of his proper name. Grant had gotten used to people first calling him gaunt Grant, and then eventually, just Gaunt.
Melody expressed her confidence. "I know you'll solve this problem as quickly and as easily as you solve all problems that come to you. Did you check out that high school group we worked with several years ago?"
"Yes. None of them remained activists. It seems that college life kept them too busy. Even their leader, what's her name..." Grant paused briefly, "Helen Athena Troy, has filled her days and nights studying music."
Melody laughed. "I'm guessing that you consulted your computer name directory. Otherwise, you'd have known her name more quickly. It seems to me that many people would jump at the chance to program an internet broadcast website. Is it true that you invented the protocols for internet broadcasting?"
"Not quite. The basic rules were set a hundred years ago. I merely organized and simplified them so that we could license and control the content of internet broadcasting. And for five more years,I keep the sole right to grant licenses for internet broadcasting, provided the courts agree with my choices. But now I have a question for you."
Melody guessed what Grant wanted to know. "The oxygen extractor is working well. We should have enough oxygen for liftoff soon."
"Great! How is the hydrogen holding up?"
Melody expressed her worry. "I'm only losing about one part in a hundred of the hydrogen for each cycle of the oxygen extraction. It looks like we'll have enough hydrogen left for liftoff but just barely."
"Hmmm . . . It would be good if you found some rocks rich with water. Then you could obtain more hydrogen and make sure you had more than enough hydrogen for liftoff. I think that the survey showed some water bearing rocks about a mile from you."
Melody laughed. "When you read about the presence of water, you didn't bother looking at how much water was found, did you?"
Grant's face showed his embarrassment. "You are right. I guess I jumped to the conclusion that it would not have been reported if it were not of practical importance. Silly me. I should be used to what other scientists find important by now."
"But you don't really need to worry about running out of water do you?"
Melody agreed. "That's correct. Lucky for us that we can recycle our water supply. We could stay here almost indefinitely except that we would run out of food in one more day. We might have to go hungry for a day or two before we can lift off."
Grant changed the subject. "Did you discover why the Oxygen tank failed at liftoff?"
"Sure did. But the oxygen tank didn't fail. The hydrogen tank is the one that failed. We had re-designed the hydrogen tanks to cut off if the airflow exceeded the safe amount. However, the hydrogen tanks still had settings calibrated for Earth. On the airless moon, because the air initially flows more quickly, we needed to re-calibrate. We've fixed the problem now."
"Then why did you lose oxygen?"
"Because the oxygen continued to flow into the reaction chamber until the computer system responsible for monitoring the reaction shut off the oxygen tank."
"I see." Grant said it in a way that made him sound like an expert on the moon rocket.
Melody grinned. Gaunt may not be a rocket scientist, but he definitely knew his electronics. "Hey Gaunt, you haven't asked me about your invisible alien detectors!"
Grant gave one of his rare smiles. "That's right. I haven't. That's because I can see from my instruments that you've already deployed them. I can assure you that no invisible aliens have landed on the moon anywhere near you."
Melody laughed again. "You know that I don't believe in your invisible aliens. Unlike you, I never saw a saucer flying toward the full moon suddenly vanish. I'm surprised that you convinced the boss to let us bring your detectors to the moon. How are they supposed to work anyway?"
"They continuously emit low intensity radio waves to get a radar picture of the surroundings. They monitor the distance between themselves and points on the moon."
"I still don't get it. How will knowing the distance between the detector and places on the moon tell you if there are invisible aliens?"
"The way an alien would make itself invisible would be to make any light or, in this case, radio waves, go around it. The radar signals would suddenly go a longer distance to reach their target. It would be as if the background target suddenly moved farther away. Yet there wouldn't be any corresponding Doppler shift."
"Now I get it. You check to see if everything stays in the same place. If something appears to move, but doesn't really move, you know an invisible alien has intercepted your radar signal."
Grant agreed. "Yes. I will let you know if any aliens, visible or invisible, have landed in your neighborhood."
"Okay, Gaunt. It's a deal. Do you also plan to use your dectors on Earth itself?
Ha! Glad you asked. I have evidence that an alien spaceship has landed on Earth, in Virginia, USA. It can't be seen by any satellite scanning. I presume that it has been made invisible. I plan to search for it soon.
"uummmm, Sounds logical. See you when I get back home." Melody smiled as she cut the connection. She wondered how Gaunt, a brilliant person, could believe in such nonsense as invisible aliens. She remembered again that many times Gaunt had sold electronic systems to Supermarket chains at cost in order to get his designs spread across the country. Were any of them alien detectors?