From multiplanetary to multistellar

Five weeks ago, CNAV considered Elon Musk’s provocative statement about making humanity a multiplanetary society. We also considered the forgotten ideas of Robert Duncan Enzmann, who sketched out several provocative ship designs before he died. Today – two days after a successful static-fire test of the SpaceX Starship – we consider an actual program for creating a multistellar society. And in fact, humanity is farther along on that program than anyone would realize.

G. Harry Stine

George Harry Stine founded model rocketry in America. He founded and ran the National Association for Rocketry, who developed the strict safety code that took model rocketry out of the “basement bomber” stage (his term, or at least the NAR’s term) and into the stage of serious, but safe, experimentation. Readers of science fiction might remember an author named Lee Correy – which in fact was Stine’s pen name. Politically he was a libertarian and a “volunteerist.” Therefore he saw space colonization as something private individuals or companies could do, without government bureaucracies or tax dependencies.

Sadly, he never saw any part of his vision come to fruition during his life. He died in 1997, and only afterward would Elon Musk create, in essence, a private space program.

But in 1973 he published, in Analog magazine, a provocative article he called “A Program for Star Flight.” Today this is still the most comprehensive attempt at a step-by-step approach to establishing a multistellar civilization. Or rather, his program could make humanity a multistellar species. In that condition, humans would have not only one civilization, but several. He never envisioned faster-than-light communications, nor travel, either. But he believed a multistellar colonization effort was still viable, even at the obvious Einsteinian speed limit. Such a program would rely on decentralization and the vesting of vast discretionary powers in key decision makers far too removed from any central authority to take “orders from home.”

Why multistellar?

Stine suggested eight possible reasons for humanity to “go multistellar.” The first, Elon Musk would definitely agree with: species survival, or at least insurance. Once humanity is multistellar, no disaster at any one star would destroy humanity completely. Stine’s seven other reasons are:

• Information – the more we know, even about the vastness of outer space, the better.
• Life search – literally searching for new life of any kind.
• Intelligence search – looking for trading partners.
• Room to live – when Stine wrote his article, people worried about overpopulation. In fact someone suggested that humans might soon be standing on one another’s shoulders, two deep!
• Sociological research – studying colony expeditionaries, in training, in transit, and as they built new societies.
• Ideology – different groups want to spread their ideas and traditions. This drove the Age of Exploration on Earth.
• Economics – money to be made, if not in the journey, then in technological spinoffs.

To this, add simple curiosity. The same view always palls, so people want a different view. The colony expeditionaries of the Age of Exploration were all dissatisfied for one reason or another. (In the extreme case, the debtors’ prisons of England yielded the colonists of the eventual State of Georgia!)

Look for a place to go

The first step in the Stine program is literally looking at stars for likely places to go. He started with an estimate by Stephen H. Dole, Ph.D., that Earth has fourteen “neighbors” of classes M2 through F2. Astronomers recognize seven broad classes of stars, labeled O, B, A, F, G, K, and M from largest to smallest. (The Sun is a G2V-type star.) By “neighbors” Dole meant that they were no farther than 22 light-years away. He guessed a 43 percent probability that we might find one habitable, or at least colonizable, planet in orbit around one of those stars.

That might be an under-estimate now. The reason we know that is that we have already begun this first step. Even before Stine’s article appeared, various space agencies had already placed several telescopes in orbit. Today a large number of telescopes are active or in planning, for scanning electromagnetic radiation from microwave to gamma rays, and even to scan for particles.

Stine had ambitious plans for a space telescope: a visible light instrument with a ninety-meter (about 300-foot) mirror. Such a telescope could optically resolve a gas giant the size of Jupiter in the Alpha Centauri system. But Stine did not discount infrared telescopes. He speculated that such a telescope could resolve decent images at 25 light years. The James Webb Space Telescope is a good start, but perhaps Stine would want to build one fourteen times as large.

What are we looking for?

The plan is to look for exoplanets – actual planets in orbit around other stars. We infer those today, by measuring the “wobble” of a star as a planet orbits it. Stine wanted only to look for gas giants, seeing them as fuel deposits for interstellar colony wagons. Indeed gas giants are the most common suspected exoplanet known to astronomers today. But Earth’s various space agencies have already catalogued more than sixty potentially habitable exoplanets. Some of these they call superhabitable – planets better than Earth, if one can imagine that.

Stine might never have imagined a habitable exomoon. George Lucas and his colleagues have, of course, imagined two. But astronomers claim to have found twenty-one already, though none have confirmed this.

Therein lies the problem. Confirmation of a gas giant, or especially a rocky planet (habitable or not), is notoriously difficult at such distances. Astronomers still can’t settle whether Proxima Centauri b, for example, has an atmosphere or not. We can only guess at such things, because no telescope presently in operation can resolve the image of an exoplanet. Which, of course, is why Stine wanted to build a visible-light telecope with a 300-foot mirror.

A project like that will take time, and only an installation already in space can undertake it. Which brings up another interesting point.

Multiplanetary first, then multistellar

The multistellar program cannot proceed until humanity has mastered multiplanetary living first. Humans need the “space cities” to support the industry to build telescopes with 300-foot mirrors. For that matter, some of the ship or probe designs under consideration, need space-based infrastructure. Powerful lasers to drive a vessel with a photon sail are one example of this infrastructure. So is the industry to build eventual colony wagons and scouts. No one builds that kind of ship on Earth! Robert Enzmann would no doubt agree.

But the biggest single reason to master multiplanetary life first, is to prepare the crews and passengers of the interstellar expeditions for whatever they might encounter. The blithe assumption that a superhabitable or even marginally habitable world will be waiting at destination would be unforgivably irresponsible. Indeed, we might never be able to confirm the existence of a gas giant before we send a colony fleet. So humanity must master the art of building livable spaces wherever we can, in our solar system. Besides making room to grow our population even more, it would give us practice. Stine did envision building solar power stations in space, and that kind of project would also be practice for colonization. The techniques for building everything from low-gravity cities to “cloud cities” (on Venus) to O’Neill cylinders would be required reading at various space force academies.

Step two – send probes

When astronomers have identified likely candidate stars that might have gas giants, Stine proposed sending probes to confirm them. He sensibly never proposed sending one ship, or even one probe, alone. So three probes would go to a distant star, using whatever propulsion system we might devise by then. Of course you want a system to drive the probes as close to lightspeed as they can go. Each probe would carry sensors to sniff for gas giants – and a big H-bomb to blow the probe up if it found a suitable one. The bright flash would tell Earth astronomers one fact: “Yes.”

The purpose of the gas giant is to re-fuel if need be. Stine didn’t treat this in any detail, but surely the probe’s designers would cram several assaying instruments on board. To design a probe properly, it would help to know the fueling requirements of a colony wagon or scout. So the shipwrights would need to build one of Dr. Enzmann’s designs, fly it, re-fuel it on Jupiter, and fly it some more. Maybe the first missions for Enzmann’s starships would be to colonize at Saturn, Uranus, Neptune, and in the Kuiper Belt.

Bu the first probes would be relatively simple, and with a simple mission. Three go out, and if any one of them confirms a gas giant, it blows up. Which means a lag time more than twice as long as the distance measured in light-years.

Step three – go!

Now comes the third step: actually mounting a colony expedition. With three probes sent to any given star, astronomers would watch for four kinds of signal. If they see nothing, then they were wrong and the star is not promising. One flash would rate later consideration. Two or three flashes would be enough of a signal to send a fleet.

And it would be a fleet. Stine and Enzmann seemed to agree on this much: to send ten colony wagons, plus automatic or crewed scouts. Enzmann’s colony-wagon designs are all modular. If something goes wrong aboard any ship, the commodore could order that other ships take on a module from the stricken ship.

The scouts that would accompany and fly ahead of the fleet would now be looking for more than gas giants. They would be looking for habitable worlds – or indeed any resources that would support a colony. This makes the practice in building space colonies in our solar system so valuable. In fact, Stine proposed sending at least three waves of robotic scouts – one light-year, one light-month, and one light-day ahead. The commodore and his staff would base his decisions on their reports – more on that later.

Governance

How would the expeditionaries govern themselves? Remember that Enzmann’s ship designs had capacities of 2,000 souls, or 10,000. The ships would start with fewer people on board than that, so the population would have room to expand.

This is enough for a small town, or a city, so Stine guessed that the passengers would form a city-state. But a starship is still a vessel – an artificial environment, like a ship or aircraft on Earth. As such, it has a captain, and the captain’s word is law. The ships as a collection are a fleet, or at least a task force, so they have a commodore. And as senior officer in charge, he has the highest authority – and that authority must be absolute.

Absolute authority goes along with absolute responsibility. We can only guess at the hazards of an interstellar journey. Mitigating those hazards, and making sure enough people arrive who can still have children, is for the commodore to decide. Any captain would be responsible for the safety of his ship and its passengers. So the selection and training of passengers, crew, and officers becomes the most important decision the launch authority can make. Psychological factors become even more important than skill sets. Skills, one can learn in class or in a library. Psychology, one must settle before launch.

Decisions

Stine recognized that the most important – and maybe gut-wrenching – decisions wait for the fleet at destination. (Or as much as three years ahead of time, depending on how fast the ships can travel.) True, the fleet won’t even set out without reasonable assurance that the star will have a convenient gas giant. But reasonable assurance is not absolute. Suppose, then, that the fleet arrives and finds no gas giant? Then they have to form whatever society they can, from the resources available. Either that, or a partial fleet turns around to return to Earth.

The launch authority can mitigate this. The fleet should set out with one or more locations of alternate destinations. So if they find no gas giant, they could make a close hyperbolic pass at the star and steer for the alternate. If they do it right, they would use only a minimum of extra fuel. But they might have to stop, send a distress report, and settle in for a century or more in orbit. That’s the worst case – and if humanity has had practice building space cities, the fleet could still build a decent society that could last indefinitely.

The best multistellar outcome

If the fleet does find a gas giant – and again they are more likely than not to find one – then they have the most options. First, they refuel. Second, they use whatever resources they find to build a refueling station. Surely other fleets will come that way, even from Earth itself.

If that’s all they can do, then with their full load of fuel they can now go to a variety of alternate targets. This includes some they might not be able to reach with a hyperbolic “slingshot” course.

But if the resources they find let them build a society in orbit around the star, that’s what they do. That goes double if they find a habitable planet or moon. Again, they come from a society that has had plenty of practice building societies anywhere. So more than likely, they’ll build a functioning society that can grow and service other fleets.

Then they can send two ships (minimum!) back to Earth with a full report. (Remember: never send one ship or even one probe alone!) The rest of the fleet can fly on to an alternate – or they can wait until they build replacement ships.

Finding even one star system with a gas giant and a habitable exoplanet or exomoon would ensure success. Such a system would form the ideal advance base to make humanity multistellar.

Variations on the theme

Stine put his program together with what humanity could build most quickly. But Enzmann did not limit himself to designing colony wagons. He did design scouts – and a scout with a crew improves the options by an order of magnitude. His Enzmann Echolance is the best kind of scout, capable of fantastic relativistic speeds. Better yet, this is a scout with a crew – and the crew’s families, so the crew can literally train their children to relieve them.

An Enzmann Echolance could reconnoiter a target system, mark every world in orbit around it, return, and report. That alone would make the program more efficient. Once the Echolance came into service, never again need any fleet take a chance on stranding itself in orbit around a star without resources.

Even if the program began before the perfection of the Echolance, that ship type, once in service, could save lives. Imagine a convoy of them escorting a gigantic deuterium tank to a stranded fleet, to refuel them and lead them to a better destination. They need not lead them back to Earth. Instead they could lead them to any advance base, or to a yet unexplored alternate.

The multistellar civilization

The result of the multistellar colony program would not be one civilization, but several, each centering around its own star. Stine admitted that the various societies could communicate but not converse. Not, that is, unless and until someone developed faster-than-light travel. Even so, any multistellar union would be analogous to the Roman Empire – or the United States during its territorial expansion. Communication would be relatively slow – literally by mail.

Furthermore, humanity would expand through an open space. Earth is closed, as Ferdinand Magellan proved with his expedition. Technically the Galaxy is also closed – but it’s so vast that it might as well be open. That definitely had its appeal to a libertarian like Harry Stine. He likely never imagined a navy in the conventional sense deploying task forces between and among the stars. One particular passage is telling:

Who will be able to afford a starship…? Perhaps any group of people who don’t like it here and want to go somewhere else.

What’s not to like? Anything from obstreperous neighbors to empire builders. We also come back to Elon Musk’s greatest desire: create as many human societies as possible. Whatever else one thinks of him, one must admit this much: he has shown great love for humanity.