Timeline of Manned Interstellar Travel, Based on Simple Economics: No Humans on Alpha Centauri Planets Until 2613

It has been estimated that a manned Mars mission would cost $100 billion. Compare this to the most recent unmanned lander, Insight, at $830 million; putting people on Mars then comes with a cost multiplier of 120.

The Initiative for Interstellar Studies estimates that an unmanned interstellar mission would cost at least "in the trillions"; Centauri Dreams cites Odenwald at $174 trillion. Assuming the same scaling, the lower and upper bounds on that then suggest that a manned mission would cost from $240 trillion to $21 quadrillion.

If on the other hand we take the projected cost of a manned mission to Mars, and assume it scales linearly with distance, a manned Mission to Alpha Centauri would cost $55 quadrillion.

It's worth pointing out here that world GDP is $80 trillion. Let's assume an annual economic growth rate over time of 2%. Let's also assume that starting tomorrow we put ALL of GDP toward such a mission - that is, every last human is working this mission and just barely otherwise just barely surviving as peasants eating crumbs.

Assuming an annual economic growth rate over time of 2%, then at earliest, we can launch a manned interstellar mission at the earliest by 2227; at latest, by 2501.

But forget about that. Because neither you, nor any other human on this planet will sign up tomorrow for their descendants being reduced to slavery for centuries for a space mission, which is what those numbers assume. So let's assume we continue to spend money on space exploration at the same rate that we in the US currently are - about 0.11% of GDP. This is already quite a generous assumption, given that most countries can't afford to dedicate such a fraction of wealth to endeavors that don't quickly return on investment. If you're more optimistic and want to set the relative rate of expenditure (over centuries) to the highest it has ever been (in a democracy - you said you were optimistic right?) that's 1966 USA, which is about twice what it is today, and only makes it happen 35 years earlier. (This is more dependent on economic growth than space program expenditure.) So let's stick with current NASA budget fraction, and assume that the future space program is ONLY working on this one mission.

By these assumptions, we can launch the mission at earliest by 2570; for the upper bound estimate, by 2845.

Our fastest spacecraft so far would take another 30,000 years after launch to get there. Let's be more optimistic and assume that the light sail technology we're talking about for unmanned probes also applies to manned craft, and can get the ship up to 10% of the speed of light. Therefore, taking into account travel time and speed-of-light delays, we wiill get the interstellar "Eagle has landed message" at an absolute cheapest earliest date of 2618.

Of course this is still unrealistic, because we're still assuming mission development starts in earnest tomorrow, assuming every government on Earth will let us use a NASA-sized fraction of their GDP for this, and that they will continue to cooperate for at least 550 years building the mission. Think of this in reverse: it's as if in 1470, the middle of the War of the Roses, and the Russians and Poles and Lithuanians still throwing off the Mongol yolk, everyone started spending money and cooperating on a project and continued to cooperate on it until this year.

I think it is unlikely, barring unforeseeable scientific revolutions, that human beings will leave the Solar System this millennium. I think it is likely that there will be civilization or species-threatening or destroying events in this millennium. This discussion of colonizing other planets to mitigate existential risks has a scatter plot listing a probability of event happening within 200 years/risk of civilizational collapse for nuclear war, coronal mass event, rogue AI, and nuclear war as 90%/20%, 70%/90%, and 95%/70%.

Using those same numbers, in the time period until launch there's a greater than a 96.6% chance of a rogue AI, and a greater than 99% chance of coronal mass event or nuclear war.

But fully automated probes could get out more quickly, particularly if we design self-reproducing von Neumann probes. We should start terraforming Mars now, as practice for remotely terraforming planets with von Neumann probes for when we eventually get there. We have time to terraform them, because if physical human bodies ever do get there, it will be in the distant future. But we do not have that much time to get the launch the hardware, which suggests we should at least colonize the Moon as insurance. Cryonics and hibernation technology at this point is still basically science fiction. These numbers are depressing given our previous dreams, but we calibrated on going from powered flight to standing on the moon in 2/3 of a century.

Space Colonies Will Be Run By Dictators; Or, Why Science Fiction Is About Government Space Travel

Settling colonies in the age of exploration was easy. Jamestown in particular seemed like a breeze. There was air, water, food, and even people who would sometimes help you if you were nice to them. Even still, it wasn't until the third ship arrived from England that the colony became self-sustaining. The Norse were unable to hold onto Greenland at all, and we still in 2018 have not put a self-sustaining colony on Antarctica . That the land does not provide basic life-sustaining commodities for free - that there is no indestructible commons where air and water is concerned - has led some political scientists to speculate that the natural state of any off-Earth colony would be that of "Oriental despotism", which earlier historians associated with the culture of the Middle East. Another way of looking at this is that there's a predisposition to strong central authority anywhere that central coordination is required for survival. This might mean political rent-seekers who control the water by force, as in parts of the Middle East, or the coordination of crops that are massively productive when huge teams of people harvest it, as with rice in East Asia. This also solves the mystery of why states emerged initially in places that were actually quite marginal for agriculture - the dry high altitude Mexican Plateau, the Nile Valley, and the Fertile Crescent (with the exception of China - still explained by a benefit of central authority's ability to coordinate labor.) On the other hand, places where berries and game almost jump into your mouth are not famous for producing large states - though they do often produce impressive cultures, like the Pacific Northwest. When you get angry at some tribal council decision, it's too easy to storm off and take your family into the next valley and start hunting and gathering there. Not so when your life depends on predicting and collectively exploiting, say, the flooding of the Nile.

But there is still another reason to think that space colonies (planet-bound or not) will resemble the walled fortress of a desert, or the absolute authority of an Eastern monarch, more than a democracy. (Yes, it gets worse.) How do you get your family to your new valley? You can walk - even if it takes a while. If you got sick of Ohio and wanted to head west, you might have to pool your funds with other families but it didn't take that many families before you could put a small wagon train together. Leaving a gravity well and building a habitat are massively complicated and expensive undertakings. This is why space launches are the province (so far) of wealthy states and so far, just one corporation. For economic reasons of massive capital requirements, space travel will therefore be performed in a way that advances the interests of wealthy states and/or corporations. (This is similar to the reason movies are more constrained, i.e. less imaginative, risk-taking, and creative than writing or visual art - they're very capital-intensive and it's much more important in this medium to make back your investment!) Science fiction typically continues to imagine it this way, likely correctly - but rarely explores the pitfalls of large organizations having a stranglehold over the means of transportation in this brave new world - or the impact of, say, aliens appearing and handing out technology that allows individual humans to cheaply travel between planets. (Libertarians - if you think having private corporations do it, you not only have to explain how they will obtain such a position in the company of a cartel of violence-monopolizing organizations called states, you have to explain why it's better to be oppressed by a privately held rather than public organization. Left-leaners, if you think states are the ideal organizations to undertake such ventures, keep in mind that the first country with a real rocketry program was Nazi Germany, and the fastest growing one today is free-speech-crushing, putting-Muslims-in-concentration-camps China.)

It's also worth pointing out that, for related reasons, such colonies will be dependent on Earth for a long, long time, much longer than Jamestown was dependent on England. Why? First off, people are much more comfortable now. Second, when the first settlers arrived in Jamestown, they were able more or less to build on their own the technology that they were accustomed to in England. Yes, in the case of iron production, English colonists actually reverted to a medieval version for a while, but they were still making the nails and blades and gun barrels and plows that they needed. What about the first settlers on Mars? Will they be able to make a smartphone? Will they be able to make another spaceship, or habitat, or geodesic farming equipment, or satellite dishes? Even assuming zero surplus mortality from the harsh Martian environment, how many ships and people are necessary before the Martian Jamestown is self-sustaining? The Martian despot will likely be interested in not just controlling the oxygen and water, but the shipments coming from Earth.

Ice on Ceres; Aqueous Chemistry...?

We're increasingly certain that there is ice on Ceres. We've known for a while that Ceres was expected to be more primitive (wetter) than Vesta. I cannot wait for February 2015 when Dawn gets to Ceres.

Good news for possible interesting interstellar chemistry. When are we going to do a sample return mission?!?

Prebiotic Source of Nucleobases Found in Comets and Molecular Clouds

Formamide. It's been found in warm star-forming regions in about the same abundances as on some comets. Here's the possible synthetic pathway.


Star-forming region LH 95. Image credit NASA.

Water Vapor From Europa's South Pole

PART I: Europa has water vapor plumes at its south poles, consistent with tidal heating (Science paper here.) These are more easily understood but no less exciting than the water vapor plumes seen last year over the south pole of Saturn's moon Enceladus, which turned out to contain organics.

Enceladus	Europa

The reason this is so interesting is not just the possibility of life in these alien oceans, but the broader implications for the spread of chemical replicators on water-containing low-gravity bodies. Increasingly it seems that many asteroids are just dried-out comets that last their external volatiles, like we just watched in accelerated fashion with ISON. It's now well-established that both asteroids and comets contain amino acids and nucleobases (PNAS paper there), both from samples of fallen meteors as well as sample return missions like Stardust, which brought back material from comet Wild-2, which turned out to have an extra-solar origin (as well as carrying the amino acid glycine). If there are replicators - either natively evolved, or von Neumann probes, mutant or otherwise - it is likely they'll be composed of easily available building blocks in low gravity environments, and spread during Oort cloud exchange between adjacent solar systems.

Another implication is that the answer to the Fermi paradox may be that we're a little premature in saying there's no evidence of life. This is especially true since humans haven't even made 50 soft landings on other bodies in our own solar system. The Dawn mission to Ceres arrives in 2015 and the findings will be interesting no matter what.

As an aside, replicators that spread between stars would ideally avoid gravity wells like Earth, because we're dead-ends, at least without expending huge amounts of energy to get back out. That said, if you think simple life at the scale of a virus or prokaryote couldn't survive re-entry simply by sheltering in a crack on a rock, try again. The C. elegans worms carried aboard the Columbia were found alive in a Texas swamp 3 weeks after the shuttle broke up on re-entry. And they're multicellular.

(Of note for amateur astronomers: here's a Twitter feed for a quick check of the positions of Jupiter's moons relative to Earth. If it's cold and clear where you live, take advantage and get out there with a telescope!)


PART II: Movie Review, Europa Report

Fittingly enough I watched Europa report about two weeks before this news came out. It's on Netflix, and if you have Netflix, go watch it right now. (Trailer) It's a recently released independent and I'd count it among the better science fiction movies I've seen. A la 2001 and other hard science fiction works, there's not a lot of screwing around with normal filmy conventions; although maybe too much character development for my taste, because character development is not what this film is for. It's a technically accurate, very un-wild-eyed tale about the first manned landing on Europa, told mostly in raw video logs from the spacecraft with occasional after-the-fact narration from the mission chief on the ground. Beyond that I can't tell you too much without spoiling the movie, but you don't need me to. My only criticism, and it's not really a criticism, is that at times I felt like it was made as a trick to get more young people excited about the next phase of space exploration. If that's true, they still made an excellent movie. (Like I said, not a criticism.)

China Lands Rover On Moon, Western Press Barely Reports

China has landed a rover in the Bay of Rainbows. Tonight when you go outside, look up; it's here:


Bay of Rainbows is the red X, upper right. It's not near any other landings, which is good for learning more about the Moon. Interactive map of the Moon and previous landings here.

The second story here is the meta-story of how little of a story this has been in the U.S. press. Only Cassini's maneuvers around the Enceladus water plumes in 2012 rival this for the lowest ratio of reporting:importance ratio. The extreme under-reporting of this event - the first landing in four decades - shows the U.S. press bias against science reporting, and/or against the possible relevance of anything that is done by someone outside the U.S. Sometimes I think it was a miracle that the Higgs boson was reported! Plus, the more groups of people we have in space (public or private), the more competition and the better for space exploration and science.

Russian Spacecraft to Land on Phobos, Return Samples

[Added later: unfortunately Phobos-Grunt ain't landing nowhere. To say the least, a real disappointment.]

Phobos-Grunt will touch down on Phobos and return samples to Earth. If we expect the surface of low gravity bodies with organic materials (like asteroids and comets) is where we'll find evidence of von Neumann probes if they exist, then this is an exciting mission. "Low gravity" really means "low escape velocity", so life materials can spread more easily, and with an escape velocity of 40 kph, Phobos falls into that category.

Dawn Spacecraft Arrives at Vesta

The Dawn spacecraft is in orbit around Vesta as I type. Of the two bodies Dawn will explore, Vesta is the more boring in terms of possibilities for organic chemistry, since it's drier. For Ceres, McCord and Sotin estimate a water contentof 17-27% by mass. This means Ceres actually has more water than Earth's oceans. Of course much of this will be present in minerals and not sloshing around loose, but that's still a much bigger reaction vessel than Urey and Miller had. In fact, if we think water-mineral interface is what matters, which is what underlies the assumption that Earth's first RNA replicators appeared in shallow warm pools where they had surfaces onto which they could be immobilized for more reactions, then most of the volume of early Earth's deep seas could have been an organic chemistry desert, by comparion to Ceres.

Unfortunately we won't know, because Dawn only has EM detectors. My wish for a landing or at least a gas chromatograph on board Dawn stems from my argument that it's exactly on small wet bodies like Ceres that we should expect to find evidence of von Neumann probes, or their descendants.


Above: gas chromatogram of amino acids found in the Murchison meteorite. The organic chemistry of small bodies, even including nucleic acid bases as in the Murchison meteorite">this paper, is usually discussed in the context of being a possible source of early replicator chemistry on Earth; this is not mutually exclusive with these materials being von Neumann probes, mutant or otherwise. Figure from Engel MH and Macko SA, Nature 389, 265-268(18 September 1997).

Both Vesta and Ceres are big enough that you can't reach escape velocity just by running (Vesta's escape velocity is a little less than a jet's at cruising altitude, and for Ceres it's a little more than Mach 1); so they still aren't trivial gravity wells (a criterion for being a good place for replicator activity). However, it looks like water vapor has already been observed escaping Ceres, a necessary step in the spread of an organic-molecule model of von Neumann probes. But I hope that Vesta surprises us, because we have to wait until February 2015 for Dawn's efficient but not-flashy ion thrusters to get it there.


Dawn's launch.

What would be really ironic is if we didn't find anything until we towed a smaller asteroid back to Earth orbit for mining.

Investigating a Comet Lifecycle

Comets are appearing more and more chemically interesting. They contain amino acids, they contain clays and compounds that are associated with liquid-water chemistry. Delivery of nitrogen to the early Earth by comets seems increasingly plausible. Most speculatively, for reasons I argued previously, we should expect to find evidence of von Neumann probes on chemically rich and active carbonaceous chondrite asteroids and comets.

However, in our brief encounters with the comets (always near perihelion), we may not be getting a complete picture of the chemistry that takes place on or around the comet. A small permanent probe or probes may be useful. Because of the volatility and small size of a comet, a single probe is quite likely to be lost after a short period.

Consequently the small ("thumbnail") satellites which were recently designed by Cornell and are now being investigated may be a good option. A comet with a short period could be targeted, so we could get results sooner and the probes wouldn't have to last as long. Multiple small probes could actually be designed to be blown back off at some point and collect data from the tail may givve us a clearer view into the full lifecycle of a comet as it warms during its descent to the sun.

The Pro-Tools of World-Building

Celebrated science fiction author Marshall Maresca pointed me to online world-building tools. They are here and here. For good measure here's a real star atlas out to 50 LY.

I'm sure I'm not the only whiner, but doesn't such a tool take some of the fun out of inventing a whole new "known space"? There are several practical upshots for authors and maybe that's the appeal: you might have lots of settings you want to keep track of, and you don't want astute readers catching you in plot holes or continuity problems that you could avoid with a more comprehensive visualization of your universe. Or maybe you could build your story inside a world like Eve, and use that as a promotional vehicle. (Who knows which one would make more money and which would just be a funnel for the core revenue source. That would also presence interesting IP problems, and for all I know probably has already come up.) My concern is that such a program does seem like it risks genericizing science fiction writing to some degree.

I like science fiction or I wouldn't write about it all the time on my blog. But of course, we're just Spaniards writing about two-legged dragons in Patagonia and Baja California as an island of Amazons, and cities of gold in the interior. There's a reality out there waiting for us to find it that will (I hope) obviate all this literature one day, like Las Sergas de Esplandian. Let's build probes! Let's send them to exoplanets! Let's put smaller more chemically sophisticated probes down on Titan and Europa! Now now now!