“No, the thing masses several tons. I don’t think there’s any way to get it to fit even if the Krechet or Chandra could handle the mass. Nice idea though.”
“We could cover more ground if the landers land in different areas, pick two biologically different landing sites.” That was Wu again. Good, focusing on the problem at hand was taking her mind off the fate of the Xīng Huā’s crew.
“But the refueling pod would only be at one site, we’re back to the same problem with landing on two planets.” Darwin said.
“The crew of one could rendezvous with the other, we have the ultralights. I don’t know about you or Xiaojing, but I’d be willing to do that,” Klaar said.
“If something went wrong with the aircraft one of the crews would be stranded.”
“So, we don’t send the second lander down until everything has checked out with the first. And we could always hike, if the air’s breathable.”
“Let’s table that for later discussion, we’re getting sidetracked again. We’ve settled that we can only do a landing on one planet, although possibly in two locations if they’re not far apart,” said Darwin. He looked at the clock. “We only have a few minutes left before we reconvene. What else?”
They continued their review of the Xīng Huā’s manifest and what impact it might have to the biology mission. They could still proceed. The other teams would be going through the same process, and Darwin hoped they’d reach similar conclusions.
∞ ∞ ∞
“All right,” said Drake, bringing the meeting to order. “Has everyone reviewed the options?” There were nods and murmurs of assent. “Okay. Understanding that we’ll have to make changes to the mission plan if we go on, I want the inputs from the team leads. Just a ‘go’ or ‘no go’, then we can get into the details. Engineering?”
“We can go on.”
“Biology?”
“We’re go.”
“Geology?”
“Go.”
“Astronomy?”
“Was there ever a doubt? Go.”
“Thank you. As mission commander, the final decision is mine. Proceeding at this point is a risk.” He paused, looking at each of his team members in turn. Some looked eager to go on, but he thought he saw hints of doubt on other faces. Peer pressure? They were hanging on his next words. “But we knew that when we started. We go.”
He heard a collective sigh of held breaths being released.
Chapter 7: Into the Centauri System
The reduced fleet continued deeper into the Alpha Centauri system in short hops. They had basic data on the positions of the planets both from the telescopic observation from Sol, and from the data returned by the Nessus robotic probe. They refined that data by imaging everything each time they moved in warp, then comparing the pictures. Anything within the system—anything big enough to be seen—would be apparent by its shift in position compared to the background of distant stars.
Aboard the Heinlein, Drake, Sawyer and Darwin were discussing landing options.
“We have photo-maps of all the planets from the Nessus probe,” Drake said, “but the resolution isn’t high and there are gaps in the coverage.”
“Gaps?” asked Darwin. “What did it miss?”
“It was under a time constraint to return the data, as well as a storage constraint. There are parts of both habitable planets that happened to be cloud-covered each time Nessus made a pass over them. Nothing sinister, the overall weather patterns weren’t the same each time, it’s just that some places are naturally cloudier, or dustier, or it was nighttime, and so on. In places we do have some excellent photographs.”
In part it had been some of those higher resolution pictures from orbit which had prompted the speed up in the mission schedule. They had shown vegetation and, in places, what might be herds of large animals. Just as significantly, they had detected no signs of civilization—Earth wasn’t ready for a first contact. The planets and their life had been there for millions or billions of years and would be for a while yet, but the people footing the tax bills wanted to know now.
“Anyway,” he continued, “my point is that we need to scan both in more detail to decide on our landing, especially now that we’re limited to landing on one planet.”
“Actually sir,” said Sawyer, “we’re limited to taking off again from one planet. Technically we could still land on both.”
Drake eyed her curiously. That was true; they had two landers, plus the backup Anderson, but now only one refueling system, with no way to return it to space once it had landed. Meaning that anyone landing on the second planet—whichever they chose as second—would be stranded. “Are you suggesting we strand somebody on one of the planets? Maroon them?”
She paused, then shook her head. A short, slow movement, they were still in freefall. “I’m not proposing it, although I imagine we could find volunteers to do just that. It wouldn’t even be for very long, we could return to Earth and bring another refueling platform in a matter of a few weeks, a few months at the most if they don’t already have them in production.”
“Months, cut off from Earth and no way to get out in an emergency. I don’t think so.”
“No worse than any early explorer. But no, I wasn’t proposing it, just making the point that we still have multiple landers.”
Drake wondered about that, but didn’t press the point. “Be that as it may, we still need to decide where we’re going to land. We need to prioritize targets, and that includes deciding whether to land on Able or Baker. My choice for mission safety reasons would be the smaller planet, with the lowest escape velocity. That will make it easier for the lander, both in landing and returning to orbit. That assumes there’s a suitable landing site.”
“There should be plenty of potential landing sites, we picked out dozens from the Nessus data,” said Sawyer.
“Right, I’m not too worried, we just need to properly evaluate them. And perhaps we could use two landers, but both on the same planet—if we can find two landing areas close enough.”
“And how do they get off again, they’d have to be close enough to refuel,” asked Darwin.
“We could use the plane to ferry the crew to the first lander,” said Drake. “You look surprised.”
“That sounds like more of a risk than I thought you’d be willing to take.”
“I didn’t say we’d do it. It’s a hypothetical we can evaluate. We would have to adjust the mission rules to minimize risk. Besides, I’d probably have a mutiny on my hands with a shipload of scientists that I wouldn’t allow down to a planet.”
Sawyer chuckled dryly. “Yeah, you might at that.” She looked pointedly at Darwin, who pretended to ignore her.
“Let’s just keep that hypothetical to ourselves for now, All right? I don’t want anyone expecting something we can’t do, and it’s a long shot.”
“Agreed,” said Sawyer. “We’re closer to Alpha Centauri A than B at the moment, so let’s do a pre-landing survey at A first. We can also set up for the anti-neutrino tomography.”
Simply put, the anti-neutrino tomography, or ANT, was like a planet-sized CAT scan. Two ships would orbit on opposite sides of the planet, one equipped with a neutrino detector and the other with a nuclear reactor optimized to emit anti-neutrinos. Differences in composition and density within the planet would, ever so slightly, affect the anti-neutrino flow differently. Most such particles would pass through the planet, and the detector, without even noticing, but slight differences could be built up into a crude virtual image of the planet’s interior in the same way a medical CAT scan’s x-rays did of a patients. The technology had spun off from instruments designed to help enforce nuclear non-proliferation treaties, for all the good those had done, but it was revolutionizing planetology.
“Can we do an ANT scan without the Xīng Huā?” asked Drake
“We still have our own reactor and the detector is on the Anderson, so yes.”
“Okay, I’ll have everyone set course for P
lanet A.”
∞ ∞ ∞
The expedition spent the next two weeks doing detailed analyses of the two Earthlike planets in the combined Alpha Centauri system. They established orbit around Planet A, or Able, and examined it by remote sensors, ANT scan and unmanned probes while doing a detail telescopic analysis of the other bodies in the system, but especially of Baker, the planet orbiting Alpha Centauri B. The latter was nearing its furthest distance from A, about as far as Neptune from Earth. They could cover that distance in about a minute in warp, but that would mean undocking all the ships and collapsing the inflatable docking hub. Since they were now limited to one landing, the undocking would wait until they’d decided where.
Both Able and Baker turned out to have large moons, roughly similar in size to Earth’s Moon, but Baker also had a smaller satellite, much further out, about one-eighth the Moon’s size.
If warranted, one of the unused landers, the Poul Anderson, would do close-up investigation of any other interesting bodies in the system during the Chandrasekhar’s stay on the surface of whichever planet it landed on, while the others would remain in orbit around the planet as a base of operations.
∞ ∞ ∞
Daily status teleconference, orbiting Able
“Physical parameters.” Greg Vukovich, the astronomer reviewed the data for the assembled team. “Able rotates more slowly than Earth, so the day is longer. It’s twenty-five hours, forty-four minutes and seventeen seconds long.”
“Is that a sidereal day or a solar day?” asked Sawyer.
“Well, given that Sol is 4.3 light-years away, a solar day is a sidereal day, but—”
“Come on, you know what I meant.”
Frank Drake thought he’d heard her mutter “as bad as George” under her breath, but he ignored it.
“As I was about to say, but I assume you mean a local Centauran day,” continued Vukovich. “The time I gave you was local noon to local noon. The sidereal day is—”
“Never mind, that’s close enough,” said Drake. “Just shy of twenty-six hours. Just the thing for people who complain there aren’t enough hours in a day.”
“How do we set the time?” Sawyer asked. “Would we just jump from 25:44:17 to 00:00:01 at local midnight, or make the hours sixty four minutes long?”
“That would give you an error of about eight minutes each day,” pointed out Vukovich.
“Roll that into a leap hour each weekend.”
“Or you could do a week of five twenty-six hour days with the weekend days twenty-five hours,” Darwin said. “Hmm, Then use the left-over quarter-hour to give an extra hour every fourth weekend.”
“What? You are wanting shorter days on the weekend? Are you a workaholic?” asked Jennifer Singh.
Drake rolled his eyes. Scientists. The by-play was amusing but it was sidetracking the meeting. Drake raised his voice: “All right, folks. You can do the clock and calendar reform on your own time. Let’s get this back on topic. Just the numbers, please.”
“Yessir. Alpha, diameter is 13,390 kilometers, a bit larger than Earth, but density is only 5.23, a bit less. The surface gravity is 9.682 meters per second squared, about 98.6 percent of Earth’s. The escape velocity is 11.42 km per second, higher than Earth’s.”
“Higher? But it has lower gravity.”
“Yes, but the larger radius means it falls off slower,” Vukovich said. “Anyway, the rotation rate at the equator is 0.45 km per second, so we can subtract that from delta-vee to orbit. It has one moon, 2876 km diameter, with surface gravity 1.322 meters per second squared, about 80% of Luna’s.”
“Thank you. What about Baker”
“Baker is a bit smaller and denser, 12,680 kilometers diameter and density of 5.76, so smaller but denser than Earth, giving a surface gravity of 1.028 gees. The escape velocity is only 11.35 kilometers a second, with a 0.48 km/sec rotational boost at the equator. There are two moons, the larger and closer is very similar to Luna, 3300 km diameter, gravity 1.6 m/sec-squared, or 98% of Luna’s. The outer moon is a bit smaller than the asteroid Pallas at 460 km, with about 12% of Luna’s gravity. Not quite low enough to just jump to orbit, but it’ll take you a while to come back down.”
“Okay, I think we’ll give Pallas Junior a miss. What are the mission implications?”
“The slower rotation of Able means we don’t get as much of a boost when launching. That narrows the latitudinal limits for our landing area. On the other hand, Able’s gravity is a little lower, so that helps. On the other other hand, the gripping hand, the lower density of the planet overall means a larger radius so by the inverse square law, the gravity doesn’t fall off as quickly on Able as it does on Baker. The escape velocity is higher.”
Drake wanted a bottom line. “So what’s the net of that?”
“We’ll know more after the close survey, but Planet Baker gives us approximately 130 meters per second more delta-Vee to play with. For what it’s worth, A’s light in the night sky of Baker will be brighter than B’s light on Able, although both are way brighter than the full moon on Earth. Fortunately we picked the right time of their years to get here.” It hadn’t entirely been good luck, the Nessus probe had returned enough data on the orbits to that the timing was a driver in the overall mission schedule. “Anyway, I’d suggest Alpha Centauri B II.”
“Good. If the biology and geology teams have learned all they can from orbit here, let’s pack up and head for Baker.”
Part II: Landings
Chapter 8: Planetfall
Centauri Station
The ships orbited above Alpha Centauri B II, also known as Planet Baker, all now docked together to form what they called Centauri Station.
“All right, choice of landing site.” Commodore Drake had the combined crew assembled in the docking hub, the largest clear volume on the now-linked ships.
“Wasn’t that decided before we left Earth?” asked Darwin. He’d been more focused on the quarantine requirements of the return until he’d been pulled in as the replacement lead exobiologist.
“Not exactly. There were recommendations based on the pictures and imagery returned by the Nessus probe, but that was a list of some dozen possibilities and subject to change depending on what we found when we got here. Conditions change, weather changes, the planet is in a different season than when those pictures were taken, and so on.” Drake flashed a list up on a large monitor screen. “Sawyer’s the planetologist, I’ll turn this briefing over to her.”
“Thank you. Here are the absolute criteria. Any landing site has to satisfy these simply to meet operational limits and mission safety requirements. One, local geography. We need reasonably flat terrain. No hills, cliffs, rock outcrops, ravines, etc, etc. A dry lake bed would be ideal—”
“But there would be nothing to see there!” Jennifer Singh exclaimed. “What would be the point?”
Sawyer held up her hand. “Relax, let me finish. Obviously we’re going to land somewhere more interesting, I’m just going over the requirements; I want you all to be aware of the constraints and what’s optimal.
“Now, as I was saying, a dry lake bed would be ideal from a mission safety perspective but, as Dr. Singh suggests, boring, and we’d miss one of the operational requirements to make as broad a survey as possible. Which brings me to the other geographic requirement. It must be near a broad mix of terrain types, including both land and ocean. However, we don’t want to land on soft ground or somewhere we’d have to worry about high tides or rogue waves.” Drake brought up a display on a second screen, a Mercator projection map of the planet below them. “Now, we’re not landing in the polar regions because of launch constraints, we need to take advantage of the planet’s rotation to get the most lift back to orbit, same as launching from Earth.”
At the planet’s rotation rate, the equator was moving nearly a half-kilometer per second compared to its north and south poles. That speed was automatically added to any vehicle launching from the equator, which could make a significant di
fference in the payload a rocket could carry to orbit. Since the return craft would have none of the usual ground support of an Earth launch, it would be at operating at the limits of its performance to return to space. The further north or south of the equator they launched from, the less payload they could carry back, until further than sixty degrees north or south, depending on other conditions, they couldn’t make orbit without leaving something significant behind, even with the assist of the planet’s rotation.
“So, that said, we’ve reduced our choices as follows.” Sawyer clicked another key and the top and bottom of the map display were overlaid with red, as were the oceans, inland areas, and mountain ranges. “River delta areas might be a great place to site possible future settlements but until we evaluate flooding risk and surface stability, they’re ruled out. We don’t want to land in a swamp.” Several areas on the map, where major rivers met the sea, were overlaid with orange.
“That still leaves two dozen possibilities, everything from coastal desert to jungle. Jungle’s obviously out because we need a cleared area to land.” More of the map turned red. “We have three survey drones to check out potential landing sites.”
“What’s the range on the drones, can we check out more than one site with each?”
“They’re solar-electric—”
“Don’t you mean Alpha Centauran electric?” Darwin piped up from the back.
Sawyer scowled. “All right, smart ass, they’re photovoltaic. The point is they have indefinite range but they’re not fast and they could run into bad weather or whatever. If there are two potential sites within a couple of hundred kilometers of each other we might be able to cover them with a single drone, but we need to prioritize. I want recommendations back from both your biology and my geology teams for the top five sites. If we’re lucky we might even agree on a couple.”‘
Alpha Centauri: First Landing (T-Space: Alpha Centauri Book 1) Page 4
