enough to tear the outer portal away and eject sphere and occupants at a speed well above Raindrop's escape value. There was a small Phoenix rocket in the station for emergency use, but Silbert had no wish to create a genuine excuse for using it. Also, since he was in the lock himself, he would probably be in no condition to get or pilot it.
5
The water sprayed in violently enough through the narrow opening he permitted, bouncing the sphere against the outer hatch and making a deafening clamor even for the spacesuited trio inside. However, nothing gave way, and in a minute it was safe to open the main hatch completely.
Silbert did so. Through the clear dome which formed the sphere's only observation window he could see Weisanen fingering controls inside. Water jets from almost invisible ports in the outer surface came into action, and for the first time it became evident that the sphere was actually a vehicle. It was certainly not built for speed, but showed signs of being one of the most maneuverable ever built.
After watching for a moment as it worked its way out of the lock, Silbert decided that Weisanen had had little chance to practice handling it. But no catastrophe occurred, and finally the globe was hanging in the greenish void outside the weed-grown bulk of the lock. The spaceman closed the big hatch, emerged through the personnel lock himself, and swam over to the vehicle's entrance.
The outer door of the tiny air lock opened manually. Thirty seconds later he was inside the rather crowded sphere removing his helmet — some time during the last few minutes Weisanen had filled the vehicle with air.
The others had already unhelmeted and were examining the “diving” suits which Bresnahan had brought inside. These were simple enough affairs; plastic form-fitting coveralls with an air-cycler on the chest and an outsized, transparent helmet which permitted far more freedom of head movement than most similar gear. Since there was no buoyance in this virtually weight-free environment, the helmet's volume did not create the problem it would have on Earth. Silbert was able to explain everything necessary about the equipment in a minute or two.
Neither of the Weisanens needed to have any point repeated, and if Bresnahan was unsure about anything he failed to admit it.
“All right.” Raindrop's owner nodded briskly as the lesson ended. “We seem to be ready. I started us down as soon as Mr. Silbert came aboard, but it will take the best part of an hour to reach the core. When we get there a regular ecological sampling run will be made. You can do that, Mr. Silbert, using your regular equipment and techniques; the former is aboard, whether you noticed it being loaded or not. Brenda and I will make a physical, and physiographical, examination of the core itself, with a view to finding just what will have to be done to set up living quarters there and where will be the best place to build them.”
Silbert's reaction to this remark may have been expected; both Weisanens had been watching him with slight smiles on their faces. He did not disappoint them.
“Living quarters? That's ridiculous! There's no weight to speak of even at Raindrop's surface, and even less at the core. A person would lose the calcium from his skeleton in a few weeks, and go unbalanced in I don't know how many other chemical ways…'
“Fourteen known so far, Mr. Silbert. We know all about that, or as much as anyone does. It was a shame to tease you, but my husband and I couldn't resist. Also, some of the factors involved are not yet public knowledge, and we have reasons for not wanting them too widely circulated for a while yet.” Brenda Weisanen's interruption was saved from rudeness by the smile on her face. “I would invite you to sit down to listen, but sitting means nothing here — I'll get used to that eventually, no doubt.
“The fact you just mentioned about people leaching calcium out of their skeletons after a few days or weeks of weightlessness was learned long ago — even before long manned space flights had been made; the information was gained from flotation experiments. Strictly speaking, it is not an effect of weightlessness per se, but a feedback phenomenon involving relative muscular effort — something which might have been predicted, and for all I know may actually have been predicted, from the fact that the ankle bones in a growing child ossify much more rapidly than the wrist bones. A very minor genetic factor is involved; after all, animals as similar to us as dolphins which do spend all their time afloat grow perfectly adequate skeletons.
“A much more subtle set of chemical problems were noticed the hard way when manned space stations were set up, as you well know. A lot of work was done on these, as you might expect, and we now are quite sure that all which will produce detectable results in less than five years of continuous weightlessness are known. There are fourteen specific factors — chemical and genetic keys to the log jam, if you like to think of it that way.
“You have the ordinary educated adult's knowledge of gene tailoring, Mr. Silbert. What was the logical thing to do?”
“Since gene tailoring on human beings is flagrantly illegal, for good and sufficient reasons, the logical thing to do was and is to avoid weightlessness,” Silbert replied. “With Phoenix rockets, we can make interplanetary flight at a continuous one-gravity acceleration, while space stations can be and are centrifuged.”
Brenda Weisanen's smile did not change, but her husband looked annoyed. He took up the discussion.
“Illegal or not, for good or bad reasons, it was perfectly reasonable to consider modifying human genetic patterns so that some people at least could live and work normally and indefinitely in a weightless environment. Whether it shocks you or not, the thing was tried over seventy years ago, and over five hundred people now alive have this modification — and are not, as I suppose you would put it, fully human.”
Bresnahan interrupted. “I would not put it that way!” he snapped. “As anyone who has taken work in permutation and combination knows perfectly well, there is no such thing as a fully human being if you define the term relative to some precise, specific idealized gene pattern. Mutations are occurring all the time from radiation, thermal effects, and just plain quantum jumping of protons in the genetic molecules. This sort of phenomenon is used as example material in elementary programming courses, and one of the first things you learn when you run such a problem is that no one is completely without such modifications. If, as I suppose you are about to say, you and Mrs. Weisanen are genetically different enough to take weightlessness, I can't see why it makes you less human. I happen to be immune to four varieties of leukemia virus and sixteen of the organisms usually responsible for the common cold, according to one analysis of my own gene pattern. If Bert's had ever been checked we'd find at least as many peculiarities about his — and I refuse to admit that either of us is less human than anyone else we've ever met.”
“Thank you, Mr. Bresnahan,” Brenda Weisanen took up the thread of the discussion once more. “The usual prejudice against people who are known to be significantly different tends to make some of us a little self- conscious. In any case, my husband and I can stand weightlessness indefinitely, as far as it is now possible to tell, and we plan to stay here permanently. More of us will be coming up later for the same purpose.”
“But why? Not that it's any of my business. I like Raindrop, but it's not the most stimulating environment, and in any case I'm known to be the sort of oddball who prefers being alone with a collection of books to most other activities.”
The woman glanced at her husband before answering. He shrugged.
“You have already touched on the point, Mr. Silbert. Modifying the human genetic pattern involves the same complication which plagued medicine when hormones became available for use in treatment. Any one action is likely to produce several others as an unplanned, and commonly unwanted, byproduct. Our own modification is not without its disadvantages. What our various defects may be I would not presume to list in toto — any more than Mr. Bresnahan would care to list his — but one of them strikes very close to home just now. Aino and I are expecting a child, and about nine times out of ten when a woman of our type remains in normal gravity any child she conceives is lost during the fifth or sixth month. The precise cause is not known; it involves the mother's physique rather than the child's, but that leaves a lot still to be learned. Therefore, I am staying here until my baby is born, at the very least. We expect to live here. We did not ask to be modified to fit space, but if it turns out that we can live better here — so be it.”
“Then Raindrop is going to be turned into a — a—maternity hospital?”
“I think a fairer term would be `colony,' Mr. Silbert,” interjected Weisanen. “There are a good many of us,
