If We Master Building in Space Then the Solar System Will Be Wide Open

Marc G. Millis, Jeff Greason, Rhonda Stevenson of the Tau Zero Foundation provided a 69-page review to NASA of the Interstellar Flight Challenges and Prospects.

A lot of the focus is on the massive speed, distance, and power challenges.

We Are Crippled Because We Cannot Really Build in Space

The most technically feasible ways to start making much faster progress to making travel around the solar system routine and fast and then to build a foundation for interstellar flight is to build large and light space structures.

It will be easier to build bigger in the low gravity of space. We need robots and new construction systems. All of our Earth-based megastructures will look tiny in comparison to the space-based structures.

Fully reusable rockets are the game changer that SpaceX is creating now. The next steps are robotic construction capabilities and megawatt and gigawatt power. No matter what the large power source is we have to build large in space to radiate the heat from the large power systems.

Going 400 Times Faster to Get to 10% of the Speed of Light

To convey the challenge of reaching 10% lightspeed, consider the improvements between the 1977 Voyager and the 2011 Juno missions. In roughly three decades there was a four-fold increase in speed. At that rate, it would take another 130 years to reach 10% lightspeed. The gap between achieved speeds and the goal of 0.1c is a factor of 400 (Juno achieved 0.00025c). The technical challenge is to increase spacecraft ∆V by at least 400 times more than presently possible with chemical rockets.

Most of the systems for useful interstellar missions would need gigawatts or terawatts of power.

Passenger Jet Travel Volumes at 1% of the Speed of Light Around the Solar System

The edge of our solar system can be defined as beyond around 200 AU. The next destination of interest past that point is 550 AU, where the gravitational lensing effect of our sun can be used to magnify images of whatever is on the opposite side of the sun. It has been proposed that this solar gravitational lens has the magnification to be able to image an exoplanet with enough resolution to distinguish land features.

This figure shows the correlation between long timescales, interstellar distances, and average flight speed. Both the distance and timescales are logarithmic. The horizontal scale spans the radius of the Milky Way galaxy (50,000 ly), while the time scale extends all the way to the certain end of Earth’s habitability (~1 billion years). The assumed upper limit for the operational duration of a space probe (200 years) is shown. The diagonal lines represent different speeds, starting on the left with Voyager’s 0.00006 c. The faster Juno spacecraft (0.00025 c) is also shown. The other diagonal lines are in terms of fractional lightspeed, shown in increasing factors of 10 all the way up to lightspeed. For each factor of 10 increase in speed, the required energy goes up by at least a factor of 100.

Going to Another Star is 500 Times Further than Gravitational Lensing Points

Beyond that point, the next targetable object is almost 500 times farther away, specifically the Centauri star systems (270,000 AU, 4.2 ly). In the vast void between those points of interest there exist only sparse densities of comets and asteroids; the Hills cloud (2,000 AU), Oort cloud (10,000 AU), and the G-cloud (41,000 AU). These features are difficult to discern using Earth-based astronomy, but probes passing through them could make direct in-situ measurements of the fields and particles.
Once past the Centauri systems, there are already eight potentially habitable planets detected within 41 ly, half of which are within 22 ly.

This chart compares the amount of energy likely to be made available for interstellar missions
(one-millionth of total world energy) to the energy required for interstellar missions. The central diagonal line is the nominal energy growth from extrapolating data spanning 1980-2007. The upper and lower diagonal lines are ± one standard deviation of that data. The horizontal lines represent the energy requirements for the following missions:
1. Ten StarShot Probes (0.01 kg total) at 20% c – kinetic energy only (1.9 x 10^13 J)
2. Ten StarShot Probes (0.01 kg total) at 20% c – energy beamed from lasers (1.8 x 10^14 J)
3. Flyby Probe (100 kg) at 10% c – kinetic energy only (4.5 x 10^16 J)
4. Rendezvous Probe (100 kg) 10% c – kinetic energy only (9.1 x 10^16 J)
5. Flyby Rocket Probe (100 kg) at 10% c, with 1 million sec Isp – rocket energy (eq. 1) (9.8 x 10^16 J)
6. Rendezvous Rocket Probe (100 kg) at 10% c, with 1 million sec Isp – rocket energy (eq. 1) (2.2 x 10^18 J)

To estimate when the energy will be available for such missions, look at the calendar year beneath the intersection of that mission energy to predicted energy availability trend lines.

SOURCES- Tau Zero Foundation, NASA

Written By Brian Wang

88 thoughts on “If We Master Building in Space Then the Solar System Will Be Wide Open”

  1. You keep repeating the same argument about introducing non-human genetics, and I keep repeating that it’s not necessary (other than maybe a handful of enzymes), therefore irrelevant.

    I don’t see why senolytic and other SENS drugs are any more crazy than the various cr*p people routinely take to treat other chronic diseases. Aging is a chronic disease with 100% mortality rate. So you deal with it the same as with any other chronic disease.

    Anyway, this discussion is a week old, and going in circles, so I’ll stop here.

  2. All current SENS research is essentially involving using crazy drugs at regular intervals for regeneration, or (in the case of the most cited research) they use a virus to administer and introduce a non-human genetic element.

    Human genetic variation is very limited due to a population bottle neck in the population 100-120kya range (based off DNA mutation rates), again look into the “founders effect” and modern human genetics.

    Introducing non-human genetics, combined with the fact that most traits are governed by multiple, often times overlapping loci. It is a recipe for disaster.

  3. Oh, they’ll find ‘good’ reasons to forbid exploration.

    Pollution will likely be the main one. Then there’ll be the ‘wasting perfectly good resources by shooting them into space’. Or the classic ‘that money needs to be spent on Earth!’ like they’re loading up the capsules with $100 bills and just shooting them off…

    But I really hope I’m wrong on this…

  4. No.

    This goes against the only empirical evidence that exists today: people’s opinion. A few years ago I studied biochem specifically to join anti-aging industry. Part of my hobbies was talking to people spontaneously about exactly this surprisingly contentious aspect.
    It was a slight majority of people against the prospect. The overwhelming majority of that majority could not rationally motivate their opposition. It was pure gut reaction, with reason a late to that knee jerk party.

    There won’t be any such certainty as in your above argument until actual concrete evidence: people actually living that long.

    It’s very hard not to see your above post as betraying a hard and stubborn bias or agenda against the prospect of aging. Which is hard to defend, tho you’re welcome to try, without also arguing against the sheer inhumaneness of robbing people of a lifespan that’s effectively as essential a human right as anything else, that medicine owes them as per hippocratic oath, etc.

    As MK says below, there’s no obligations. Only opportunity to make one’s life whatever they wish, more so than today where death from old age is involuntary. That subtle difference doesn’t sound like what you meant.

  5. Considering how relatively cheap e.g. SpaceX is poised to make LEO/BEO, it’d really be something if this time around we again retreated from space like after the Apollo era.

    The loss leaders are significant, but the returns once past that inflection point make Earth almost insignificant — strictly from a habitat construction POV. Nothing in our solar system will, in the short and medium term, compare with Earth’s natural comforts, but the real estate and resources BEO are immense, even for our primitive means of exploitation.

    Like a slightly wet but gigantic firecracker. Like a long, unpowered train on greasy tracks just before the downward slope starts in earnest.

    In the slightly longer term it will be hard to stop people from creating their own self-sufficient social circles, whether as actual politically independent states or not, and this combined with ever improving technology ought to dissolve much of the dependence and subservience to politics that characterizes most of the modern world.
    Except for security, as ever with technology’s multiplicative effect of good and evil.

    The more humans spread out, the lesser existential risks get, the further we get towards the point of no return: the practical infeasibility of extinction (many dark tunnels eventually reaching light), and/or the curing of aging (light at the end of a very long tunnel), and/or scarcity reduced to negligibility (infinite tunnel building ability).

  6. > My final note: human psychology. Most people would would kill themselves or everyone around them before they lived 400 years.

    Psychology follows culture and societal infrastructure. All of these are quite adaptable.

    We used to live much shorter lives with a lot less free time and a lot fewer options. There have been multiple cultural and societal transformations and revolutions. We’re still doing fine.

    Besides, nobody’s forcing anyone to live longer than they want.

  7. > Fixing one trait might have terrible implications on another. […] Trying to figure out that Intricate problem, then to do the same for multiple non-human species in order to introduce their genetics to ours is something that we have no idea whether it is actually possible.

    That’s closer to what George Church etc are trying to do, not what SENS is about (mostly). AFAIK, the main genes that SENS wants to add are mitochondrial genes that we already have and genes for a few specific enzymes that are better at clearing various junk.

  8. > SENS would practically require 3d printing a human to exact specs […]

    Not really. Stem cells can be administered in-vivo and do the main regeneration work.

    > […] cell regeneration genes […]

    Don’t know about that. There are multiple groups working on SENS-related research, likely with slightly different approaches at each.

    IMO, SENS can be done with no genetic manipulation other than generating and rejuvenating stem-cells. At most, there would be ~20 or so added genes for a more complete package. See my longer replies for details on that.

    I don’t know if maybe you’ve skipped this, but this gives a decent summary of the key ideas of SENS: https://en.wikipedia.org/wiki/Strategies_for_Engineered_Negligible_Senescence

  9. (part 2)

    IMO, SENS can consist of:
    (1) Senescent and cancer cell clearance.
    (2) Replacement of lost cells with rejuvenated stem-cells.
    (3) Breakage of protein cross-links.
    (4) Clearance of other extracellular junk.

    None of these require genetic manipulation, other than stem cell geneneration.

    (1), (3), and (4) can be performed by suitable medical agents (small molecule drugs, macromolecular drugs, enzymes, etc) and/or immunotherapy. (2) is stem cell therapy. The agents can be administered periodically, and over a certain treatment period (e.g. X biweekly treatments every 5 years) to minimize the required dosages, cell replacement rate, and side-effects.

    The remaining categories of damage can probably be left untreated, since they deal with intracellular problems, and damaged cells will eventually get replaced anyway by the above.

    But I agree that a complete SENS package will include genetic manipulation. Specifically, to backup several mitochondrial genes in the nuclei, to encode for a handful of better enzymes to clear intra- and extra-cellular junk, and maybe to modulate telomerase. No complex changes to metabolism or to the immune system are needed (immunotherapies involve training the immune system, not genetically editing it – at least not directly). The whole shebang is maybe 20 genes or so out of ~20000, in areas unrelated to reproduction.

    In contrast, George Church and others’ genetic approaches to fighting aging involve much more extensive gene therapies.

  10. (part 1)

    > “repeated senescent cell clearance” is a form of genetic manipulation.

    Not necessarily. A senolytic drug needs to do 2 things:
    1. Identify senescent cells using their biomarkers.
    2. Selectively trigger death of the matching cells.

    There are many ways to trigger cell death, e.g. puncturing the cell wall. Genetic modification isn’t required for this.

    (The same can be done with cancer cells using other biomarkers. Recent cancer immunotherapy does something similar via the body’s existing immune system, and has seen some remarkable success. There are ways to do that without using the immune system.)

    > All major academic works that look at gene editing to make SENS a reality need genetic manipulation. [emphasis added]

    Sure, if you a priori look at papers about gene editing approaches, then of course they’ll require gene editing. The bulk of the publications list on sens.org deals with cell therapies, not genetic manipulation.

    > The problem […] is that you have to introduce non-human genetics […] At some point it stops being human […] and you create a new species that may or may not be able to procreate

    A) In my personal opinion, being human is overrated. I see it a starting point, not a panacea.
    B) More importantly, AFAIK, they neither intend nor need to introduce so many foreign genes that would result in a new, incompatible species.

    (continued in reply)

  11. Master building honeycomb shapes in space. Strong, light weight per volume, uniform shape in beams, can build them multidirectional and or layered or stacked Potentially easy to repair if a beam gets knocked out. B-bots in space. Hive module supplys the honey sticks to build the structures.

  12. I’m not going to bet on us not sabotaging ourselves. For all the ‘best’ reasons, we’ve got a political class that seems intent on solidifying their power over the population, which will eventually lead to a stagnation and decline, not prosperity, innovation and growth.

  13. SENS would practically require 3d printing a human to exact specs, even then given the known DNA needed to make it work, you are talking Lizard People.

    Humans have a very limited genome due to an extreme founders effect early in our populations history.

    The cell regeneration genes they want to use in current academic research share loci with everything skin related. Overlapping loci. All the regeneration genes they are looking at are derived from lizard or salamanders. So humans will have scales.

    We are already 90%+ Banana. See the problem.

  14. SENS is speculation beyond the wildest horizon of human genetics. The level of genetic manipulation required for SENS might not be possible without creating an entirely new species. Multiple loci traits, super limited genome to work with and that sort of thing.

    Given the focus of the current SENS research on salamander and lizard DNA for regeneration, maybe the idiot conspiracies have it right with Lizard People

  15. That would work, provided you use a huge gene bank and have artificial wombs. Otherwise I see some human psychology and sociological problems happening. You also still need a generational ship, it just means you don’t have to expand your population and it should preferably be all women to start, so you have an egg supply to introduce variation. Sperm is easier to store and collect in mass. 🙂

  16. So, it is crazy genetic manipulation where you have to introduce non-human genetics. Go look at the actual research papers, they all focus on the introduction of non-human genetics. Can’t work with what you don’t have. The million or so Chimpanzees left on earth, have more genetic variation than all of humanity.

  17. My final note: human psychology. Most people would would kill themselves or everyone around them before they lived 400 years.

  18. Most genetic traits occur as a cumulative effect on multiple loci, Different traits frequently overlap along the same loci. Fixing one trait might have terrible implications on another. The way the traits operate and how the loci interact with different traits is the result of millions of year of evolution. Trying to figure out that Intricate problem, then to do the same for multiple non-human species in order to introduce their genetics to ours is something that we have no idea whether it is actually possible. Yes we have been able to manipulate single loci traits, but not multiple loci ones. The problems with those grow exponentially with each loci. Every loci you change it might actually impact traits you did not target.

  19. “repeated senescent cell clearance” is a form of genetic manipulation. All major academic works that look at gene editing to make SENS a reality need genetic manipulation. The problem that they face is that you have to introduce non-human genetics to make it work. Human genetics are subject to a founders effect, so we have a limited variation and the positive traits from mutations at human procreation rates take awhile to accumulate and some may have been lost, since they may have not been “positive” from an HBE adaptive standpoint when they originally emerged. All traits are relative to environment.

    At some point it stops being human when you add too much non-human genetics and you create a new species that may or may not be able to procreate with extant modern humans (Homo sapiens). Unless genetics hits a point where every gene is controllable and we understand every loci and how they interact, what you say is impossible.

  20. I think there are fewer things that you can’t teach though a computer than you think. But in order to rely on stored media to revive a skill when needed, it really needs to be better characterized than most of the skills civilization relies upon are at this point. Too many black arts and proprietary technologies right now; You’d launch your generation ship, and 50 years out it would turn out you couldn’t make some needed article because the manufacturer had been cagey about how it was actually manufactured.

    The ability of computers to teach skills is likely to expand dramatically over the next few decades, as the increasingly expensive and broken education system gets displaced by computer aided homeschooling. But proprietary technologies are likely to be a continuing problem, barring some real reform of the patent system to remove the incentive to hide things.

  21. But, at any given point, about 50% of the planet is on the night side, and in most of that area (where people are asleep), energy use is reduced. So arguably, there should be around 30-40% of global capacity available for other uses at any given time (though getting that energy to where it’s needed is difficult).

  22. One of the sub-fields of SENS, OncoSENS, specifically deals with cancer. Their main approach is inhibiting telomerase, to limit the number of times a cell replicates. WILT, or Whole-body Interdiction of Lengthening of Telomeres, is its more extreme variant (not my favorite idea, I admit).

    Apart from those, the general way that SENS deals with cancer is two part:
    A) Elimination of senescent cells, which (I think) are the most likely ones to become cancerous. The same techniques can be used to eliminate actual cancer cells. (This is covered by damage category #4 – death-resistant cells, which can include both senescent and cancerous cells.)
    B) Replacing exhausted cell populations with fresh (young) stem-cells. (This is covered by damage category #1 – cell loss.)

    Our bodies have a natural tissue turn-over, and this mimics that in a more controlled fashion, removing and replacing cells before they become cancerous. Individual cell rejuvenation (epigentic reset) has been demonstrated, and as you probably know, the probability of young cells to become cancerous is much lower than old cells.

    Keep reading. You’ve barely scratched the surface, if even that much.

  23. True a gene bank of sperm and eggs from a large number of individuals could work. You would still need a decent number of women otherwise you would essentially have a few women acting as baby machines. You also need a large enough population for knowledge transfer. Like you said, you need enough skilled individuals to start and throughout history there has been this problem that you need enough people not only to preform those skills, but to teach them. When the population of skilled individuals gets too low, those skills can get lost in the preceding generations. There are a lot of things you cannot teach through a computer.

  24. Round trip they have to live close to 800 years. Are you trying to establish a colony? If yes, then you have to reproduce and you wan’t to start with a big enough gene pool.

  25. SENS does not address cancer and other replication errors that occur in DNA over time. Cells will replicate and die, unless you turn off that gene. Even without much negative outside stimuli, as cells replicate, each time they do so it increases the chance of a replication error. Those errors if in the wrong place, lead to cancer and various other degenerative conditions more often than not. SENS cannot solve that problem, only gene editing can. Then their is a limit to human genetic variation, ever hear of the “founders effect”. Go talk about SENS with a geneticist and they will tell you that well it has potential that potential has it’s limits. Those limits are genetic. No matter what you try to do with SENS, its still just a band-aid, SENS borders on pseudo-science, even if it does draw from a number of legitimate medical fields.

  26. Money to be made is too… narrow an interpretation.

    Benefit to be gained.

    The Apollo project didn’t make profit, but it was a serious campaign in the war of ideas, image and status that was the Cold War. And hence gave a huge benefit.

    Just like (and I know I keep mentioning this but it strikes my fancy) if Kim Jun Un used a nuclear cannon to put a 5000 tonne anything in orbit, that would cement his place in history as something other than “Asian Hereditary Monarchs, 1 AD – 2500 AD, page 5678.” Even if it was just an orbital tomb* for Great Leader and Dear Leader, that would be an unavoidable sign in the heavens of greatness.

    *Ramses the Great would be revolving in his grave fast enough to accelerate the African Rift Valley. Because a 5000 tonne freaking STAR in a permanent orbit would be the peak of awesome monumental tombs.

  27. I read a novel set in ancient Inca times… that turned out to be on a generation ship. The theory was that the originators looked for the most stable culture and went with that for their generation ship, and the protagonist was in the generation that had to be culture shocked back into the 23rd century or whenever when they finally reached their destination.

    In practice I think the Inca empire barely lasted a century and wasn’t stable at all, but ancient Egypt or something could be a possibility.

  28. Beyond the predictability horizon (50 or 100 years from now) is such a vast range of technological factors to permutate with, that it’s hard (understatement) to come up with a detailed comparison for all of the most credible strategies.

    If we can upload, then a non-negligible new dimension to the subject is whether “people” will still want to go in the first place. If we can “upload” then travel time would ostensibly not be an issue anymore; just a different solution to the time problem that anti-aging addresses.

    If we can upload and there’s such a thing as computronium, then the distance to stars and arguably to galaxies is a non-issue. It would become a bigger issue to identify what existential motivations “people” would have, then. Interstellar/galactic travel is probably much lower on the to-solve and to-do list by then.


  29. <<No matter what, if expect your population to go on for multiple generations, you need 60 people and some crazy mating restrictions to make it work or 360+ with normal taboos (no 2nd cousins or something). >>

    This is speculation beyond the predictability horizon. Not least because there is zero empirical basis for predicting what humans (and more particularly still, humans on an interstellar ship) will be like once they get to live multiple centuries. Ideally not just the first humans who necessarily live thru (and to some degree be a product of) the transitory period between pre- and post-aging, but more “steady state” arbitrarily-aging humans.

    And again the rest of the real world picture needs to be accounted for. Other tech like artificially induced torpor, or possibly total freeze, could be part of the tools for interstellar trips.

  30. Michael accurately gave credit for the complexity of the problem. Geriatrics and gerontology are both more complex by far than SENS – in fact that complexity is a fundamental reason for SENS not being another metabolism or pathology strategy.

    The aging process is not magic. Taking out the garbage natural aging produces is not magic.

    Maybe when you’re done with ad hominems and strawman fallacies this back and forth will head somewhere useful.

  31. It’s not ignorance to state the facts of an empirically identified dynamic. Natural aging accumulates damage. Removing that damage is not “fictional magic”, nor just “a pill”, nor “ignoring genetic limits at every level”. In fact it’s working with the limits; it provides for taking the garbage out. Unlike gerontology and geriatrics.

  32. Further down this comment thread you discredit aging damage mitigation therapies for the fact they “do not exist yet”, a fallacious argument on its own; but already you argue in the above comment:

    <<Ghost in the Shell level, consciousness transfer>>
    Which is even more of a speculative prospect. It’s stated as fact when it’s even more “hocus pocus” than SENS.

  33. If the vehicle was low mass, used beam propulsion (avoid the rocket equation), and used the unused, night-time electrical-generating capacity of Earth then one could imagine a decently capable and relatively near-term mission.

  34. Maintaining genetic diversity in a small population is basically a solved problem, given the capacity to freeze gametes. You just have some sort of lottery where people occasionally have to have a kid from the gene bank, in addition to one from their partner.

    The real minimum population size is going to be driven by issues of cultural stability, (You don’t want a Jonestown halfway through the trip!) and minimum number of active skillsets needed. You can revive skill sets from stored media if there aren’t undocumented tricks involved, but a given population size can only have so many different skills active at a time.

  35. Personally, I’m more in favor of non-biological living (more precisely, post-biological). But that’s a whole ‘nother topic for another time.

  36. The whole point of biological existence is to spread your genes. You are advocating a 1 gen population that somehow lives forever though Hocus Pocus, MAGIC SENS.

    Yes, you are advocating nothing but fictional magic, we live forever with a pill, ignoring genetic limits at every level. Better living through chemistry, right? Pure ignorance.

  37. It’s a far more complex problem than you are giving it credit. No matter how you want to address it, all genetic variation has it’s limits. The aging process is part of that finite variation.

  38. I looked up SENS, it looks like it has gone nowhere. It seems like a celebrity type fad. Like super foods making you live longer.

  39. The real problem introduced by having waypoints pre-launched and on their way to the destination is that unlike Science Fiction space theatre, once ‘our’ spacecraft gains appreciable speed, it cannot be stopped (or speed-changed) quickly to match the intended intercept fuel tank. In fact, its just a pain in the âhrse.  

    Ideally, you’d want ot overtake the tank of juice at almost exactly 0 m/s without ‘wasting’ thrust to braking. This would be done by the tank of fuel traveling more slowly than the spacecraft, having the SC pass it by, and accelerating at just the right time (and acceleration rate) to deliver the intercept right on the money some time down the pike. 

    The fuel transfer happens, and the tank’s empty mass is ejected. It doesn’t have enough fuel to do anything except drift endlessly forward.  

    But when you think on that, you realize that the mission would have to have a fair few fuel tanks pre-launched, perhaps up to hundreds of years before the main launch, to be in the right spots at the right times, for intercept.  And what might the spacefaring origin peoples create in those intervening hundreds of years?  VERY probably, something far more capable than the originally envisioned probe+flying-tanks concept.  

    Just saying,

  40. Granted, there’s still a lot of research to do in SENS, but there is growing evidence to support it. In particular, senescent cell removal (senolytics) has had some remarkable results lately.

    Specifically regarding cancer, cancer is caused by misbehaving cells. They misbehave because something is interfering with their normal function. Be that accumulated genetic mutations, various damage to the cellular machinery, external junk, etc. That’s exactly the sort of thing that SENS tries to address. Healthy undamaged cells don’t become cancerous.

    It does sound like you aren’t familiar with SENS, so perhaps you should take your own advice, and read up. Watch a few lectures, maybe. Read the literature. Don’t take my word for it.

  41. Got it, hocus pocus. There is this thing called cancer, the more a cell replicates, the more likely to crop up. Also, you need intense genetic screening. The smaller the population the more likely stuff can crop up even if it’s low prob. I am guessing you are not a geneticist and just read a cool article. Genetic variation if finite. Go look up HBE (Human Behavioral Ecology) and read some stuff by, or better yet learn how to model the human genetics of physical adaptation and behavior by looking at the works of Richard McElreath.

  42. I did say further down the line. Artificial wombs etc aren’t required. They’re just an extra option.

    Keep in mind that we’re not likely to send any crewed interstellar mission in the near 50 years at least, by which point we may well reach Star Trek like level on several fronts. We’re already past or approaching Star Trek on a few, particularly in fields related to computing.

    The artificial wombs etc are being developed now. There already somewhat working prototypes. And they aren’t huge facilities either.

  43. People used to die at a much younger age, so the biological limit may be much higher than you might think. Personally, I’m not convinced that there is a biological limit on longevity. I’m optimistic that we can achieve indefinite lifespan with a full SENS package, maybe even with a partial one.

    Full SENS does involve “mild” genetic manipulation like moving certain mitochondria genes into the nucleus. But it doesn’t require “heavy” genetic manipulation like rewriting our metabolism or immune system.

    In case you’re not familiar with SENS, the idea is that aging is caused by accumulation of 7 key types of damage, and by fixing that damage, it may be possible to reverse aging to some degree. If you can keep a person functioning at a 40 or 50 y/o level by periodically removing those damages, then you avoid the diseases of old age, which are the primary causes of death. If you can keep doing that indefinitely, then you’ll end up living indefinitely (barring fatal accidents).
    It’s like keeping a classic car functional by routine maintenance, whereas it would be a pile of rust a long time ago without it.

    Such treatments could basically be a type of pill that you take once in a while. But even genetic manipulation isn’t technically complex. The techniques and equipment are reasonably simple. The hard part is knowing what to modify.

  44. Building a ship plus having facilities to do the whole artificial womb thing, plus gene editing is too Star Trek, as in, its not realistic. At what point is it still human (Homo sapien) anyway?

  45. I am pretty confidant that getting people to live 400 years w/o cybernetics (think Ghost in the Shell level, consciousness transfer) is not possible. There are biological limits to any organism, no matte how much you screw with it. Think about the “chainsaw hands and beaver” argument if you will. The genetic variation does not exist to allow for such adaptations. If you try to fix one thing, you may change another, try to change too much and its not the same organism and then you have to create them in a lab every time until you have a genetically viable population. You seem to think that they will be able to handle this stuff in deep space. Whatever population you send, you want it to continue, crazy extreme gene editing only complicates that.

  46. I think that repeated senescent cell clearance at regular intervals should give us a pretty big boost of healthspan just on its own. There are a few other SENS techniques that don’t rely on gene editing, which address things like protein cross-linking etc. Combined, that might be enough for a 400-year non-generational trip. But full SENS does indeed involve some gene manipulation. I don’t see that as a show-stopper.

  47. So like I said, anything short of gene editing and you need a certain population with enough room for growth. Then social dynamics set in, which requires a even higher population to offset the female to male ratio over time, or you are at risk of bad stuff. Remember that monogamy was the bribe paid to the working class, by the wealthy. Various forms of polygamy ruled before that.

  48. There could be multiple redundant copies of the data, allowing for a lot of error correction. But if that’s still a problem, use larger probes and add shielding. The probes don’t need to be fast if they multiply exponentially at each stop.

  49. There’s some research on turning somatic cells into sperm and egg cells. As I recall, it was already demonstrated, but probably still needs to be perfected. So I wouldn’t worry too much about limited eggs supply.

    Add to that artificial wombs, which are also being developed, and statistical genetic engineering further down the line (find all healthy variants of each gene in the human population and their statistical distribution, then use that data to semi-randomly engineer an egg and sperm). Then one could, in principle, repopulate from just a few cells.

    But if we fix aging to the point of radical life extension, then a 400 year trip wouldn’t be generational anymore. Then all of this reproduction talk is moot.

  50. The problem with that is P ~ F*Isp, so if your Isp is that high, either your thrust is tiny, or you need HUGE amounts of power.

    But as MTCZ points out, (nanotech-based) ISRU precursor probes are an interesting alternative. They could be launched via the laser-wisp method, then build up the large communications and other infrastructure from local sources on the other end. Slowing down is tricky, but if the probe can take the form of a small light or magnetic sail, it might be doable.

    If by then some of us upload to nano-computronium, we might even hitch a ride on a probe like that. Or maybe we’ll eventually figure out how to use ISRU to set up a micro-wormhole (should be far easier than a macro wormhole), and then the computronium can be sent through that.

  51. Think of it this way, you have to plan mating with 3 gens at 60 people even if you have a 3:1 female to male ratio and each woman has to have 6 viable offspring, two from three different mates. At 360 that becomes 1.5 partners per gen at 2 gens until it becomes a free for all, much more inline with current human habits. Only the first generation and early second gen would have restrictions if you go with a 1.5-2:1 female to male. Much more doable, when you consider dynamics.

  52. Think a punnett square: x2+xy+y2=1 where x and y are the different genes provided by the different parents. Automatically when you have a dominate and recessive you get a dual variable for X or Y so you square the whole equation. Then for each generation you square it again to get your outcomes. For each generation add +1 to the exponent. You need to get to the 4th gen zygote (5th power) before inter-familiar mating can occur at a minimum, to prevent a huge runaway of recessive genetics. That gives you 3-4 gens apart with 60, if done right.

  53. Really, it would be gene editing that could solve it, It’s solving menopause, just as much as aging. I am not sure that is doable. Women are born with a fixed amount of eggs in their ovaries. No matter what, if expect your population to go on for multiple generations, you need 60 people and some crazy mating restrictions to make it work or 360+ with normal taboos (no 2nd cousins or something).

  54. Error correction code. Right now DNA is encoded in such a way that it can correct for a single error.

    You have to realize how small the cross section of a poppy seed is. I think many of them will make a trip of many light years without colliding with a cosmic ray.

    I also think if they get hit by a cosmic ray particle the poppy seed is toasted.

  55. Spider fab 3.0 being able to build the airtight shell of a rotating habitat one section at a time would be almost as big as BFS.

  56. And they will never survive the millennium long trip through deep space without the enclosed DNA being scrambled by cosmic ray impacts.

  57. Well if you are doing the generational ship thing to go the 378 years, you need a minimum starting population of 60 with highly controlled mating 3:1 female to male ratio, else you might get some unwanted receive genetics cropping up. Preferable is more like a population of 360 with roughly 2:1 female to male ratios and enough room to expand to about a population 1000-1500. That would have to be a pretty big ship.

  58. 3: Once you have metallic aluminum, extrusion of slender structural members to be assembled by robot should be a relatively simple matter. By bringing some ceramic, or tungsten extruder parts up from earth, extrusion of steel, and titanium should be possible.
    Additive manufacture of metal structures should be made easier by zero gee. The metal will tend to stay where it is deposited. Devising a way to do additive manufacture without first making wire would help. Heat treating should be made easier by vacuum, build a big ceramic box, and shine lots of light on it.

  59. If we are serious about building things in space, we must use materials obtained there. Bringing materials up earth’s gravity well is absurdly uneconomic.

    Here’s the plan:

    1: Establish permanent bases on the moon. One base should be at the best source of water, and other volatiles, presumably polar craters, another should be at the lunar equator, near a good source of aluminum, iron, and titanium rich regolith.
    The polar base could be powered by PV, the equatorial base should have a nuclear power plant so operations need not be curtailed during the lunar night. Mining and ore concentration at the equatorial base could be done continually, with daytime launches by electromagnetic catapult done with energy from PV.

    2: iron, aluminum, and titanium ores(oxides) should be reduced to metal by concentrated solar radiation in the vacuum of space, with the oxygen captured from some of the smelting for use as atmosphere, chemical synthesis, and use as reaction mass.
    Titanium might be smelted away from other infrastructure, and the oxygen lost because of the high temperatures involved, relative to iron.
    Titanium is purified by the Kroll process here on earth, but I suspect that with high enough temperatures, and vacuum to dispose of oxygen, a “brute heat” approach could be used. After all, in zero gee, vacuum is your crucible. I see no reason why metals could not be separated by fractional distillation in space.

  60. All life is is information. The ultimate way to seed the galaxy would be to transmit a beam of light that could bootstrap matter into a life form. The hard part would be to get that first molecules of RNA to form. But once you do that you are half way there.

    BTW, if you think it is impossible, you do realize we are here and it was random.

  61. There is no reason to sent people when we can send DNA and information. The ultimate devices for populating the galaxy are star seeds. Poppy seed size probes with tissue size solar sails. They will grow anywhere there is light and water. And if they find the right environment they will grow an entire ecology including people.

  62. In those timeframes, if STL, I would consider (cough layman imagination cough) ISRU precursor probes out to the periphery of our system and at destination. Those could offset the launch mass loss. For better retro propulsion at destination? Or refill other basic resources.

    Hundreds of years from now means it’s not unlikely that all the ISRU/mfg/propulsion/telecom techs make it feasible. Unless the imagined mission launches tomorrow.. Just ISRU and mfg ought to have some meaningful progress by the time we’d have actually built whatever main mothership was supposed to survive a 375yr (+whatever overengineering/redundancy margins) trip.

    Basically a similar dynamic as our present plans for orbital refueling. Funny that – LEO is halfway to anywhere (in our star system); Oort cloud is halfway to anywhere (beyond our star system) ?

  63. Nice charts.
    Totally agree. ISRU and manufacturing are the two things we need after cheap orbital access, to be in space *for good*.

    After that the solar system is ours. To span beyond those distances we need to cure aging, solve fusion or similar energy levels, or “solve” FTL travel. But curing aging would flatten all other obstacles by virtue of us having time on our side.

    If we don’t sabotage ourselves, a future is coming where we finally come out of our cosmological prehistory, down here in this gravity well of space and time.

  64. LOL, if you like beers that in any other nation would be considered not just bad, but undrinkably awful. I rather like a well aged goesse though. Better around the 4 year mark, I’ve found. Nice and tart. The funk takes on interesting herbal-and-fruity overtones. Undertones? Quarter-tones? GoatGuy

  65. Part 3

    Tho’ I’ve posted it scores¹ of times, but Tsiolkovsky’s Rocket Equation makes figuring this stuff pretty easy. That and the E = ½mv² thing to convert energy to velocity, and so forth.  

    E = ½mv² so… inverting
    v = √(2 E/m)

    E = 5 MeV
    E = 5,000,000 eV × 1.6×10⁻¹⁹ J/eV
    E = 8×10⁻¹³ J/nucleon

    m = 4 AMU
    m = 4 g/mole ÷ 1,000 g/kg ÷ 6.022×10²³ nucleons/mole
    m = 6.64×10⁻²⁷ kg/nucleon

    v = √(2 × 8×10⁻¹³ J ÷ 6.64×10⁻²⁷ kg )
    v = 15,520,000 m/s

    ISP = v ÷ 9.81 N/kg
    ISP = 1,583,000 sec

    At utilization of 20% of nucleons, productively… (in Tsiolkovsky’s equation)

    ΔV = 9.81 × ISP • utilization • ln( M₀ / M₁ )
    M₀ = 1 (the whole enchilada, at launch)
    M₁ = (1 – ⅔)

    ΔV = 3,410,000 m/s (now divide by 299,792,458 m/s for ‘c’)
    ΔV = 1.14% of c.

    Alpha Cen is 4.3 LY.

    t = 4.3 LY ÷ 1.14% of c
    t = 378 years

    Just saying,

    ¹scores … archaic grouping of 20-at-a-time. Like dozens is groups of 12.

  66. Part 2

    Just saying: if 20% of the D-D fusion produced alphas could be gainfully deflected without losing their 5 MeV kinetic energy, AND if our steampunk era space ship were to reserve ⅔ its mass as Deuterium for acceleration, and another ⅔ of the remaining as deceleration, then getting to Alpha Cen is only a 375 year proposition.  

    I say “only”, just to show how limiting even direct fusion ions are with million plus ISPs, at getting us to the stars in anything approximating the Human Attention Span interval. HASI

    The author rather charitably set a line at 200 years for spaceship operational survivability. This I believe is much more related to the HASI than actual spacecraft ageing and decomposition. Certainly one can envision rather do-able-in-the-future highly redundant robotic repair mechanisms that’d keep a starship going for far longer than HASI.

    But still, arriving at Alpha Cen, you’d only have (⅓ of ⅓) or ⅑ of the original launch mass. And get there in 375 years. 

    Could do some darn interesting science though!
    Especially if outfitted with dozens of fine telescopes.
    And interferometers, magnetic field sensors, all that. 
    And AI brains to poke around for hundreds of loiter years. 

    Communicating back to Old Earth by laser!
    Why not… 

    Mightn’t be a 2 way conversation, but 1 way data is good enough.
    If anyone’s still aware to listen in, 375 years down the pike.

    Just saying,

  67. Its a fun article, I have to say.

    The biggest problem is one of energy, in the end, for all these dreams of interstellar space flight. Energy and as the first graph points out, mass & time. Obviously we can get to any place we want, simply whizzing around at the speed of a comet, but the time it’d take to traverse even to the nearest stars is prohibitive (25,000+ years!), and by rights we could actually just use a comet as The Boat, too.  

    Likewise, we can get to most anyplace we want quickly (at least by Relativistic standards), if both mass is near nil, and energy is huge but still not mindblowing. The idea(s) of using large lasers to accelerate gram-scale wisps of “spacecraft” to low percentages of ‘c’. No room for people tho. Not even significant room for communications, controls, computing, instrumentation.  

    Energy, compactness, per joule density, Tsiolkofsky’s Rocket equation, ISP and so forth all figure in big. But again, in the end, its all about energy. Energy, mass, time.  

    The most intriguing (i.e. not magical) ideas so far seem to center on harnessing fusion to produce really energetic reaction charged ions, then using electric fields to attract-and-reflect those “away”, to gain thrust. Remarkably high ISP. Because MeV nucleons got punch, baby. 

    5 MeV alphas have V = 15,500 km/s. ISP of 1,580,000. 
    Now that’s cooking.

    Just need a 5 million volt gradient to reflect them. 
    No problem. 
    1950s atom-smasher stuff.  


  68. The Trappist planets are at ~40ly, they might consider that too far. I am more surprised Ross 128b is not on the list. Evidence is building that it might be the most earth-like yet, its 11ly away.

  69. Build on moon. Build space elevator on moon. Lift thing built on moon to space. Moon boss give you promotion. Go back to moon house and fuck moon wife.

  70. To build in space. Need a canister full of magnetic eyelets on perferated flatstock. Several arms on either side of the canister. Hole on either side. Arms take out and bolt together. Magnet pieces find ferris pieces and voila arms have some drills attached. Belly of cannister also has magnetic attraction to bars.

  71. The Destinations of Interest list is missing Ross 128b. It is looking better than many others as a possible more earth-like world.

  72. Begin a Manhattan project on the bootstrapping Brainiac 2090. The Brainiac will work on various propulsion strategies for rapid transit across the galaxy. It will set up experiments to validate various promising ideas.

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