Encounter With Tiber

by Buzz Aldrin

  The only catch is that that’s a lot of random solutions to study, and you need a big, fast computer to do it. But nowadays, when every mission carried more computing power than the whole Earth had had in the year 2000, that was hardly a barrier anymore.

  Fifteen seconds clicked by, and then the solution came out. It was remarkably close to what Captain Gander had put in in the first place, as I pointed out. “Yep. And sometimes it’s not. Well, put it in and let’s do it.”

  Once again, my job was to watch the computer and make sure that what it was doing was a good thing to do. The one thing you really can’t build into machines is common sense and gut instinct, and so even as advanced as they’ve become, we still have to watch to make sure that what they’re doing makes sense for our purposes. But once again, everything went fine, with some minor tinkering on my part, and shortly we were both closer to trajectory and at a better angle to the Sun for our power plant.

  Captain Gander had been watching me closely. I didn’t think much of it. If I’d been commanding a mission this important, with so many irreplaceable human beings on board and a pilot I hadn’t used before, I’d have been watching pretty closely, too.

  When I finished the sequence, he said, “I’m sure you’re aware I knew your father.”

  “Well, yes, sir,” I said. “The astronaut corps was pretty small in those days; I guess everyone knew everyone.”

  “True.” He looked over at the record of the correction; I had throttled back twice when one of the small rocket motors on one booster began to run hot, but that was all. We were right in the groove. “I just wanted to mention that I don’t think he ever had the patience or discipline to do the kind of job you do, as well as you do. Probably you’ve heard things like that from other people, before.”

  “Sometimes,” I said. “I think it’s not quite as much of an issue for me as it is for some others.”

  We didn’t talk much more on that shift; I hoped I hadn’t said the wrong thing. The truth was that I was well coordinated, with a good but not great head for math and science, and liked a challenge; very possibly I’d have been an astronaut even if Dad had been a plumber. People were always wondering what I was trying to prove, or trying to reassure me that I didn’t have to prove anything. It was kindly meant, but I just didn’t feel that I needed it.

  The first few weeks slid by; most shifts were uneventful. Traditionally everyone brought along a few projects to study, because there simply wasn’t much for a crew of ten to do between boosting out of Earth orbit and aerobraking into Martian orbit. I spent a good bit of time studying the little that was known of the Tiberian language, with help from Vassily Chebutykin, and learning from Nari and Dong the basic way a dig worked. In turn I coached Kireiko and Tsen on the flight simulators.

  I spent other time reading, listening to music, or asleep. Now and again I’d find myself sitting with Olga and watching the stars wheel around from the cockpit window. We never quite broached the subject of the crews coming after us in GOcycler Aldrin and what effect that might have on our relations with the rest of the crew, but we’d hint at it in passing. Or we’d have a meal together and talk about what it was like to grow up rich and famous, as I had, or to struggle up from a working-class family to becoming an engineer, as she had. We had some things in common, like skiing and enjoying mysteries, and some things that the other person couldn’t fathom: she had no idea what I saw in American country music, and I couldn’t begin to understand what she liked about twelve-tone stuff. It seemed to be developing like any friendship does, in fits and starts, getting to know each other, becoming gradually surer that the other person really likes you.

  Several of the scientists were qualified pilots, so once a week Captain Gander would have Nari or Vassily take the commander’s chair, with Paul or Ilsa as pilot, while he had a meal with Olga and me in the commons, with the door closed, and we talked about things in general.

  After one such meal, four days before the Mars Five Alpha crew were to intercept the MERC, back at Earth, he leaned back and said, “Well, it’s getting close to the day. The best thing that could happen would be to have everyone on board here shout ‘Hurray! More help!’ but I’ll be pretty surprised if that’s what happens. I’d settle for just having it all blow over after some angry words.”

  Olga nodded. “Vassily thinks the Chinese are already suspicious. He says that Dong has not been as forthcoming as usual and seems sort of troubled. With private e-mail you never know what people know anymore.”

  The captain shrugged. “Well, I guess we’ll find out soon enough. It was like this on Phobos One too, you know. We had a crew of five, one from each space agency, and sure enough there was a reason why everyone had to plant his feet on Phobos first.”

  Olga smiled, a tight little smile without humor. “The Russian on that mission is something of a friend of mine.”

  If it was a hint, it didn’t seem to bother Gander. “Dmitri was one sharp guy, which was how he got the other slot in the two-man lander. I think if I hadn’t had an eye on him, I’d have heard the door slide open behind me and turned around to hear our arrival announced in Russian.”

  “And you think he was dishonest?” Olga asked.

  “Hell, no, he was perfectly straightforward about it. I respected him highly as an opponent, and if he’d pulled it off it would have done great things for his career, I’m sure. It would also have trashed mine, which is why I wasn’t going to let him. No,” and Gander’s voice dropped low again, “that kind of thing was really more like a game than anything else. This, unfortunately, is very real. I do hope from the bottom of my heart that the planners are wrong and everyone will be friends—just like we were on Phobos eventually. But I have to think about worst cases.”

  Olga took a sip of her cocoa and shrugged. “Well, Dmitri Tomasovich always spoke highly of you, and I think he thought of it as a game as well, so I guess I can see how you managed to be friends. To me, the whole sordid business of national pride in these missions seems silly—we’re in a tiny metal box that is the only place where we can survive for millions of kilometers. You’d think we’d be smart enough not to fight inside it.”

  “You would think so,” Gander agreed. “The trouble is whether it’s true or not. That we’re smart enough, I mean.”

  “If we aren’t, nature has a way of correcting the problem,” Olga pointed out.

  “Right again. Well, anyway, I can’t think of anything else we can do to prepare, and to tell you the truth I can’t think of anything that anyone else can do about it on this ship. They can be mad at us, I guess, but we still have twenty weeks left in the voyage. That ought to be time enough for them to cool down.” He paused for a moment, and then said quietly, “And you know, Olga, I do understand that you’re right in principle. If there’s anywhere where you can get a feel for that, it’s Phobos. The horizon’s so close, and there you are where you can throw a rock into orbit, or with an extra heave throw it all the way to Mars, and where a hard jump leaves you hanging above the world for several minutes and three good bounds will take you all the way around the narrow part … and all the time, hanging up above you, taking up almost half the sky, is that huge red planet … you start to notice that you’re a little bit insignificant in the scheme of things. You start to wonder if you should take yourself so seriously. And, well, it still took a while, but five nations learned to share it.”

  “Five people learned to share it,” Olga said. “That was the easy part. And right now the Earth looks like a tiny shining dot, from our viewpoint, but the inhabitants are not much better at sharing than they were in the days of Alexander the Great.”

  “In fact, he got that title by not being very good at sharing the world with everyone else,” I pointed out. “I don’t think we can anticipate other people’s reactions. We have no idea what pressures they might be under from their home countries, or how they feel about the pressure, or even whether there’s any pressure at all.”

  They both looked at
me, slightly startled. Usually at these little gatherings I only talked about technical matters, but Olga and Captain Gander loved to get into the philosophy of things. “I think,” Olga said, “that it has been pointed out that we are theorizing in the advance of data.”

  Gander chuckled and nodded. “Yeah. And we are. All right, we’ll just play it as it lays, when the time comes.”

  When the news came, four days later, everyone was sitting in the common area, with the door open to the cockpit so that I could hear as well. Since the ship ran on Universal Time, we had gotten into the habit, as a crew, of catching the relay of the BBC six o’clock report together, just before the evening meal. As might have been expected, it was the lead story; the moment it began, everyone fell dead silent.

  I listened with half an ear; the teams of scientists coming along were indeed distinguished, and the BBC seemed to be spending a lot of time explaining how a cycler worked. They had an annoying habit of calling it a “MERC cycler,” silly because the C in MERC already stood for “cycler,” and I was kind of surprised at how much time they spent telling people about how orbital mechanics worked, but then I guess doctors are always surprised that the news has to tell people what the liver does, and lawyers probably wonder why the media always has to explain habeas corpus.

  Whatever the reason, it stayed quiet in the common room while the BBC announcer explained that to get from Earth to Mars, you have to get into an orbit that will intersect the orbit of Mars at the time that Mars will be there. When you leave the Earth, you are already moving at its orbital speed; to catch Mars, you need to modify that orbit so that you climb out away from the Sun, reaching your peak distance from the Sun—aphelion—just at the moment that Mars passes through that point.

  Mars takes almost exactly twice as long as the Earth to go around the Sun. Imagine two men running at steady speeds around two parallel circular tracks, so that the man on the inside track is running faster than the man on the outside; then the inside man “laps,” or passes, the outside man at regular intervals. When the Earth passes Mars, it’s called an “opposition.”

  When is the easiest time for the inside man to pass a football to the outside man? Just before he passes him; that way the inside man’s speed is added to that of the ball, and the ball has the shortest possible distance to travel before it overtakes the outside man.

  When is the easiest time for the outside man to pass the football to the inside man? Just before the inside man passes him: he can throw the ball inward toward the center of the track, using some of his speed, and let the faster inside man catch up with it.

  Thus Earth-Mars missions, whether they are going to Mars from Earth or to Earth from Mars, leave some time before opposition and arrive sometime after it. Oppositions come up every 780 days, on the average (it varies because the orbits are not perfectly circular). Since the opposition of March 2010, we had been sending probes to Mars (and to its moon, Phobos) on every opposition. From the opposition of 2014 on, we had been sending equipment and supplies for bases at Crater Korolev and on Phobos. And, of course, for the opposition of July 2018, Walter Gander and his crew had departed on the MERC Aldrin in May 2018 and arrived at Phobos in December 2018.

  NASA had hit on the idea of naming any Big Can habitat that ended up permanently in space after one of the early astronauts. When the time came to name the two that would become the Mars cyclers, Armstrong was already taken as the name of the space port at L1, so that made it easy to name the two Big Cans that were to become the Mars cyclers “Aldrin” and “Collins,” after the two other Apollo 11 astronauts. There was something else that was appropriate about the name Aldrin being the first one to make the voyage; Aldrin himself had worked out the basic principle of the cyclers, back in the mid-1980s and added further refinements a decade later.

  The point was simple in concept and difficult in execution. If you timed matters right, a spacecraft returning from Mars via a long trajectory could intercept the Earth from behind, a short time before an opposition. Since it would already be moving faster than the Earth’s escape velocity, it would not go into orbit around the Earth; the Earth’s gravitation would simply bend its orbit into a large ellipse around the Sun. But while this was happening, the spaceship would acquire some of the Earth’s momentum, a process known as “gravity assist” that had been used since the Voyager missions to the outer planets in the 1970s and 1980s. The ship would be whipped up into a new orbit around the Sun—if the timing was right, one that would take it right back to Mars, without the expenditure of any fuel except minor quantities for maneuvering. Using its heat shield, the ship could then “aerocapture”: slow down by passing through the Martian atmosphere, and then go into orbit around Mars.

  The system was known as a REcycler (Return to Earth cycler). Theoretically you could have a “full cycler” in which the ship passed endlessly back and forth between the Earth and Mars on a twenty-six-month cycle. In a REcycler the ship always refueled in Martian orbit, boosted out of Martian orbit carrying returning crew back to Earth, dropped them off to Earth using the Pigeons it carried, and was gravity assisted back to an aerocapture, so that once again it was in orbit around Mars with its tanks empty. This had provided huge savings for the Mars program, because each crew left in a MarsHab, like the one we were in now, which it then flew down to the surface of Mars, where it became one of the buildings for the small human settlement at Crater Korolev. Returning crews always left the MarsHabs in place for future use, and came back on Aldrin or Collins. That way every crew that went out built up the size of the base at Korolev, because a new MarsHab went out with each. Crews coming back used Aldrin or Collins, and thus we not only never brought back anything that was more useful on Mars, but we always sent the cycler back with a gravity assist.

  In theory crews could have ridden out to Mars on the MERCs at any time; all you had to do was catch up with them as they whipped around the Earth. But there was a lot concealed in “all you had to do.” They came in and out very fast; a Pigeon with a strap-on booster could just barely catch a MERC as it whipped by, and if it missed, the Pigeon would be well above escape velocity, bound out into a solar orbit with air and power for perhaps a week at best.

  If trouble happened early enough, they might be able to abort into a very high orbit that would take them back to L1. Otherwise, when they reached Aldrin, they would have to depend on its being fully functional. Telemetry of course would have assured them it was, and another crew would have gotten off just days before, but where an empty MERC coming back to Mars with problems was no big deal because crews from Phobos or Korolev could overhaul it once it reached Mars, if anything was wrong when they got on, they would have to live, or die, with it until they reached Mars more than five months later. All in all, it was a high-risk maneuver, and we and the Russians were each betting a five-person team of our very best people on getting it right the first time.

  I might have expected the dead silence that greeted the announcement that Russian and American crews in augmented Pigeons had successfully overtaken and docked with Aldrin. Space is truly international in this: the moment you hear of anyone doing anything dangerous, no matter where they are from, the first thing you want to know is if they’re all right.

  What I hadn’t expected next was Nari’s whoop of joy, or Paul shouting “Bravo!”

  I missed the first part of things, because I had a job to do and needed to keep my eyes mostly on the screens, but by the time Olga relieved me, it had turned into a full-fledged party. What all four of those of us who were in on it—me, Captain Gander, Olga, and Vassily—had forgotten was just how international science really is, and has been for a long time. Our scientists here in the MarsHab knew every one of the named group coming on Mars Five Alpha; to them they were friends and colleagues, names and faces to see again. And more than that, though they hadn’t voiced the concern much, our team of specialists knew, perhaps better than anyone, that even seven of Earth’s most brilliant people was a very small number f
or a puzzle of the scope and depth they were expecting. The effective team had just more than doubled in size, and this meant a far greater chance of success.

  In the middle of the excited uproar and chatter, Gander dropped an arm around my shoulders and said, “Well, I guess everyone was wrong. And isn’t that a surprise? Just out of curiosity, Jason … do you think there’s any way we could try a radio call to Mars Five Alpha?”

  “Well, you know the obvious. We’d have to get a position and course for it so we can point one of our antennae at it. Might take a day or two before we could find that out. Then there’s the question whether anyone there would be on radio watch for signals from our direction, and after that I guess—”

  Paul said, very loudly, “Got them!”

  We all turned to look—all except Dong and Ilsa, who had been assisting him. The three of them were clustered around one of the terminals. I bounded lightly over in the one-tenth g and was startled to see a piece of e-mail on the screen—from Robert Prang, the Mars sedimentologist on Aldrin. “How did you—”

  Paul shrugged. “I thought of it before they did, or before any of the rest of you. But it’s obvious. We send a radio message, compressed data format, every fifteen minutes, back to the relay stations in Earth orbit. A lot of it is telemetry from different machines on the ship, some of it’s the video recordings we made for our families and friends, and a great deal of it is Internet traffic. We all correspond with our colleagues via e-mail; the big reason why the Mars Consortium has to keep our addresses unlisted is only so we won’t be deluged. Well, it occurred to me that if any of us knew a private address for any of those colleagues over on Aldrin, their communication arrangement was probably similar to ours. And as you can see, it happened that it was.”