by Jeff Pollard
“Why is there a window?” Richard Branson asks.
“Because,” Kingsley looks to the animation behind him. “Because that.”
“The station in lunar orbit,” Josh Yerino explains to Richard, “orbits along a plane that doesn't move respective to the background stars. But the Moon rotates, so that orbit shifts a little every day. The Moon has a 28-Earth-day long day. And so every Earth-day, every 24 hours, the lunar surface has shifted 1/28th of a rotation relative to the orbit. Now you might be wondering why we use a polar orbit rather than a more equatorial orbit, and the answer is that the eventual goal of this project is the establishment of a base on one of the lunar poles, and if you are going to and from the poles and a polar orbit, there are no launch windows, you have constant access, but the downside is that non-polar latitudes are only accessible for a few days ever two weeks, and only for a few days with sunlight every four weeks.”
“Right, magic, got it,” Branson replies.
“After our four day surface-stay,” Kingsley says, “we rendezvous with the station, we deposit the Pegasus back at the gas station, we take the Griffin back to Earth for a powered landing less than a mile from where I am standing. Then ULA launches a month later, nobody cares cause we already beat them, we get the massive contract, we do so many launches that we build up a massive fleet of reusable rockets, we bring the price to orbit down by an order of magnitude and I retire on Mars. Any questions?”
“The Commander and Flight Engineer have been incapacitated on the lunar surface. You must now pilot the Pegasus back to lunar orbit,” Josh Yerino says over an intercom into the Pegasus module simulator. Caroline and Richard Branson stand at the controls, facing the simulated windows and held up by bungees to simulate 1/6th gravity.
“Alright, it's just the two of us,” Richard says.
“Let's do this,” Caroline says sarcastically.
“Do you have the guidance computer on?”
“I think so.”
“Select the target, it's the orbiting space station,” Richard says. Caroline presses buttons, navigating through her rendezvous target options.
“I don't see it,” Caroline replies. Richard leans over to her side to look at the list of targets.
“There,” Richard points.
“SS Marie Juliette?” Caroline asks.
“SS stands for SpacEx Ship, and I don't know why it's Marie Juliette, but that's what it's called.” Caroline nods and hits the button next to the name and selects the target for rendezvous. Her multi-function-displays switch to showing a diagram of the Moon with their current position as a dot on the surface and the SS Marie Juliette's orbital track overhead.
“Hawthorne, Pegasus,” Richard calls.
“Go ahead Pegasus,” Yerino calls back.
“We have guidance computer in automatic rendezvous mode, over.”
“Copy.”
“Is there anything else we need to do?”
“Familiarize yourself with the flight plan, the altitude and velocity check-points, in case the guidance computer fails, you'll need to fly it manually.”
“Oh sure, I'll just memorize this and fly it manually, got it,” Richard says sarcastically.
“Engine arm on, rendezvous radar on, you getting this?” Richard asks.
“I got it,” Caroline replies, having been day-dreaming. “Engine arm on, what else?”
“Rendezvous radar on,” Richard repeats.
“Got it.”
In the simulator-control-room a hundred feet away, Kingsley sits with Josh Yerino, watching the internal camera feeds showing Richard and Caroline as well as the telemetry.
“Okay, we've got ignition,” Richard says. K can see the two astronauts buffeted by the simulator rig. The bungees that simulate 1/6th gravity are released and they are returned to Earth gravity, simulating liftoff from the lunar surface.
“Let's see what this does,” Josh says as he pushes a button on one of his many touch screens. Alarms ring out in the capsule.
“Hawthorne! Hawthorne we've got a bunch of shit in here. Lots of warning lights. I got GDC override, Abort override, Uplink failure, Hawthorne are you getting this?!”
“They can't hear you,” Caroline says calmly.
“Why?”
“Uplink failure, the radio's broken. They want to see us fly this manually.”
“Shit,” Richard says, taking the controls and looking to his indicators. “Where do I go, there's nothing on here. Which way is it to the station?”
“Umm, here, look,” Caroline points to the display showing the SS Marie Juliette's orbit respective to their position now rising above the lunar surface.
“They missed pitch-over,” Josh says.
“No shit,” K replies.
“North, it's to the north, okay,” Richard says. He pitches the Pegasus module away from vertical, aiming her due north.
“And they're dead,” Josh says.
“Yep,” Kingsley agrees.
“Wait!” Richard shouts. “It's coming towards us. We need to match its speed, not go towards it!” Richard flips the Pegasus around and aims her to the South. A new alarm goes off. “Orbit Alarm. What does that mean?”
“I don't know,” Caroline replies.
“Shit,” Richard declares. If either of them were paying closer attention, they would see that their remaining delta-V was at 1600 m/s and dropping. Since they had begun their gravity turn in the wrong direction and now had to double back, they no longer had enough delta-v to reach orbit. The fact that trying to continue to orbit is a futile exercise has yet to occur to them.
“Should we end it?” K asks Josh.
“They're supposed to see the Orbit Alarm and realize they have to abort and land instead.”
“Yeah but for the real mission we're not going to have a backup Pegasus, so they're dead whether they fail to make orbit and crash or if they land safely and then wait to run out of oxygen.”
“Maybe dying in the simulator will make them realize they need to work harder.”
“Come on,” K says. “This simulation includes Tim and I both dying on the surface leaving the two newbies to try and get home by themselves, and then a failure in the guidance computer. We don't need to practice bleeding.”
“Don't cover for her, she's not ready, look at how little she cares. They're still trying to get to orbit, neither of them are looking at the data.”
“She'll be ready.”
“Well, we can agree she's not ready now,” Josh replies.
“What about Dick, he's screwing up too.”
“He's at least trying, he cares, look at her!” Josh points to the screen. Caroline appears bored.
“She'll be ready.”
“You will be some of the very first people to practice lunar field geology. Only twelve people have been before you. There's a whole lot of Moon left to explore,” Exogeologist and Canadian Astronaut Victor Tremblay says as he leads the crew of Pegasus 3 on a hike in the desert of northern Arizona.
“Well, here she is,” Victor says as they reach the rim of Meteor Crater. What had looked like a ridge now reveals a cavernous crater before them. “This is perhaps the clearest crater we have on Earth. It's about a kilometer across and about two hundred meters deep. We have craters that are hundreds of kilometers across, but they are so large and so eroded that you wouldn't realize you were standing in a crater without satellite pictures or a degree in geology. But this is more like what you'll be seeing on the Moon. Come on down,” Victor says as he starts the arduous hike down the slope and into the crater.
“Here on Earth we have wind and rain that erases these craters. You can see the gullies made by flowing water, but more or less the crater is intact. The reason this crater is so clear and crisp if you will, is that it's very young, only about 50,000 years old, and it's located in a desert, so there's little hydrological activity to wash it away. We think this crater may have only been 10,000 years old when hu
mans first set eyes on it, so we're talking about a very recent impact in geological time.”
“Okay, here's a good spot,” Victor says, stopping. “You are detectives at a murder scene, let's put together what happened. When this crater was found, it was thought to be the leftovers of a volcano. So let's look and see if that's the case. Look around you, in the ground, what do you see?”
“Rocks,” Caroline replies.
“Okay. What kind of rocks? Are they volcanic rocks?” Victor asks.
“No,” Tim replies. “These aren't volcanic.”
“Good,” Victor says.
“Sandstone,” Kingsley says.
“Right! Coconino Sandstone. We find this all over the southwest from Colorado to Utah to Nevada and Arizona. It's formed by wind blowing very fine particles around into dunes. Wherever there used to be massive deserts filled with wind-blown dunes, you find sandstone. There are parts of the Grand Canyon that have over six-hundred-foot-thick layers of sandstone and we've dated it to about 260 million years ago. So if this wasn't volcanic, what was it? We need to go deeper!” Victor leads them down a steep trail, deeper into the canyon.
“Suck up,” Caroline says to K. Victor stops the group after a difficult descent to about midway down the crater wall.
“Okay, now what do we see?” Victor asks. “Anybody at all.”
“Go on tell him,” Caroline elbows Kingsley. “You know it, surely.”
“Do we have a question?” Victor asks.
“Yeah, why are you training us? Why don't we let the exogeologists do this?” Caroline asks.
“I'm supposedly going to be going to this alleged Moon base I've heard so much about on TV. But even if we have a team of exogeologists on the Moon, it will take many of us decades to fully explore the Moon. You four will be the first to see Tycho Crater and your observations will be invaluable for years to come.”
“And you're going to be the first woman to walk on the Moon, you really want to get there and have no idea what you're doing?” K asks.
“So what do we have?” Victor asks.
“Is it limestone?” Richard Branson asks.
“Right! This particular kind is called Toroweap Limestone and is part of the Toroweap Formation. This layer is darker than surrounding layers making it easy to spot on say the wall of the Grand Canyon. It contains some gypsum and shale. However, here is our first big clue. On the Grand Canyon wall or just about anywhere you look in the southwest you'll find Toroweap Limestone above the Coconino Sandstone, and we've dated it to around 255 million years ago. So here, and nowhere else, we find these layers are reversed with the older one above the younger one. Hmmm.” Victor continues the descent, stopping when they are just about to the bottom of the crater wall.
“Now what do we see?”
“Crystals?” Tim asks, crouching down and examining the rocks near the bottom of the crater rim.
“Right, we've got crystals, some white, some gray, you might see a little pink in there. There's also a little yellow-brownish tint, that's from the iron content. If you find a really nice rosy-pink color, that indicates higher content of manganese. This is called dolomite, and we call this specific layer the Kaibab Formation. This is about 250 million years old and we see it all over the southwest. Again, the younger layer is beneath the older layer. How can that be? We have to go deeper!”
They reach the crater floor, with the crater rim now towering fifty stories above them. “Now what you have here is pretty boring stuff, this is called mudstone, and it's basically that, dried-up old mud. This layer is called the Moenkopi Formation and it's about 245 million years old. Now across the whole southwest, we find these same four layers, but in the opposite order. You might come here and think, maybe these aren't the same layers? But we look deeper, look at the fossils, look at the fine details like the iron and manganese content and we find that these layers are indeed the same. So how could it be that these layers were reversed? No volcano does that. A volcano might come up, stretch the layers, explode, then leave a crater, but the layers would still be in the right order. So some said it could have been caused by a meteor. However, did you see any heavy iron chunks of meteorite laying around? Is there a massive iron asteroid sitting in the bottom of the crater? No. This led many to the conclusion that it couldn't have been a meteorite, because a meteorite big enough to do all this would have been massive and would have been here.”
“They did find several tons worth of small iron meteorite fragments around the crater, but nowhere near the amount they thought was required. This led to a man named Daniel Barringer speculating that there was a hundred million tons of iron meteorite under the crater. He spent nearly thirty years trying to find it, but never could, because there wasn't a massive meteorite. What they didn't realize was that most of the meteorite was vaporized in the collision and only small fragments could remain. The smoking gun, so to speak, was the discovery of stishovite and coesite, these are rare silica formations created when quartz is hit with a massive shock-wave, something that volcanoes can't do. We call it shock quartz and how it formed was a mystery until we started doing underground nuclear tests, and then we found shock quartz all over the place.”
“Now we know that a meteorite of about three-hundred thousand tons, not a hundred million, hit here at a speed of over 20,000 mph. It hits the ground and then begins vaporizing as it plunges deeper and deeper into the Earth. The vaporized rock creates a massive over-pressure which blasts all this material up. So what we see is that the layers have been peeled back by this impact and they came back to rest in reverse order, and much of the material was blasted out and into a thin layer on the surrounding landscape. On Earth, this impact reveals these deeper layers, but we also have rivers carving canyons that show us the same layers. On the Moon, there are no rivers to carve canyons, and so we need some other process by which to see those deeper layers. Since impact cratering is the primary geological process on the Moon, that means that all over the surface we have craters on top of craters on top of craters, and all of those impacts have blasted material out. With lower gravity than on Earth, that ejecta blanket travels much farther, so that an impact on the southern hemisphere can easily lay down ejecta material on the northern hemisphere. That means the entire Moon is slowly accumulating fine layers of ejecta. Thus if we go into a very old crater, it'll be difficult to get below a thick blanket on the surface of ejecta material from everywhere else.”
“But, you will be landing near Tycho Crater. Tycho is one of the youngest craters on the Moon. It's very white, that bright coloring, or albedo, is a sign of its youth. Typically the darker a feature is, the older it is, and Tycho is very bright white, like snow. This means that Tycho is not going to have a very thick layer of ejecta material from other lunar impacts. It's a bit of a clean slate if you will. We thought Tycho was about 200 million years old. Why did we think that? Because the Moon is constantly being bombarded, and so when a new feature is made, wiping out the old craters, then this new feature is pristine. Until it is hit with new meteors carving out smaller craters here and there. By counting the small impacts and knowing about how often the Moon is hit, they estimated Tycho to be about 200 million years old.
But on Apollo 17, a quarter of the way across the Moon, they picked up samples that we think came from the Tycho impact, and we radiometrically dated those samples to 108 million years ago. We think that's the age of Tycho. You will tell us for sure. Tycho Crater is also a very large crater, you can see it with the naked eye from here. That means it excavated very deep into the lunar crust, which means we'll be able to see very deep into the past.”
“Now, you think this crater we're standing in is large, a kilometer across, about a quarter kilometer deep. Tycho Crater is 86 kilometers across and nearly 5 kilometers deep. This is a massive crater. We think the Tycho impactor was from the Baptistina family of asteroids, but we don't know for sure. There should be chunks of the impact asteroid strewn around the crater rim, where
you will be landing, and so, if you know what to look for, if you can pick up the right rocks, you'll be able to tell us what the Tycho impactor was made out of, we'll be able to exactly date the impact, and when we look elsewhere on the Moon, we should be able to find a layer of ejecta material matching the composition of that asteroid and that will give us an exact date for that layer of lunar soil.”
“The science of geology, and any science, really, comes down to the building up of data. If we didn't know the order of these layers you see around you, we never would have realized they were inverted. So when I'm living on the rim of Shackleton Crater in ten years on the Moon base Kingsley's building for NASA, If I take a core sample, I will be able to identify the Tycho impact layer and that will give me a benchmark, I will know exactly how old that thin layer is, and that will tell me more about the layers around it. I will be able to do my job better and discover more about the Moon's history, assuming you can do your job and get a piece of that asteroid.”
“It's this kind of build up of knowledge that will lead to discoveries. Nobody knew what killed the dinosaurs, but we knew that they suddenly disappeared from the fossil record 65 million years ago. Then we discovered that there was a thin layer that marks the end of the dinosaurs that's rich in iridium. Then we found a massive impact crater caused by an iridium rich asteroid 65 million years ago. You put those pieces of information together and you discover the cause of a mass extinction. Who knows what we might discover about the Moon by building up seemingly innocuous data and putting together a more complete picture.”