First of all, I’ve finally decided on a name for the ROV: Mercury, after the US’s first manned spaceflight program.  I’ve decided to name my first three ROVs Mercury, Gemini and Apollo, after America’s pre-shuttle era spacecraft.

Now, time for some photos:

This photo shows the lower half of the ROV, now with all four of the bilge pump thrusters installed.  The thrust from the pumps is directed using a combination of flexible plastic tubing and PVC pipe fittings.  As luck would have it, the size of plastic tubing that fits snuggly over the outputs of the bilge pumps is also just the right size for 15mm PVC pipe to fit inside it very snuggly.  At the back of the ROV is a small black plastic box which all the wires feed into, which is where the relays are housed.  Once absolutely all the wiring is done (which isn’t yet), I’ll completely flood this box with melted candle wax, so that when it sets the entire things is totally waterproof.  You can see a short “tail” coming out the end of the ROV.  The plastic PVC end cap you can see at the end of this is the beginning of a screw-shut coupling I’m making from a PVC barrel union.  This way I don’t end up with the full 30m tether permanently attached to the ROV.  You can also see some orange nylon rope running between the very beginning of the tail and the black box: this length of rope is slightly shorter than the lengths of cable which run from the box to the same point on the tail, so that if tether gets snagged on anything and the ROV runs right out to its full length, the nylon rope will absorb the shock of the sudden stop, rather than the cables.  The two sets of thin red and black cable from the box to the front of the ROV will carry power to the lights.  Also visible in this photo are two new lengths of PVC pipe underneath the mounting grid, which weren’t included during the initial round of frame construction.  These are where ballast will eventually go to keep the ROV neutrally bouyant.

Above is a (rather blury) photo of the camera I’m planning to use (on the left).  It’s designed to be installed in a car as a reversing camera, and I got it off eBay for $30.  I had thought that a reversing camera would be ideal for use on a ROV for a number or reasons: they’re small, cheap, designed to work in low light conditions, and they run off 12V DC.  However, since getting one I learned of a few details that make them less than ideal: for one thing, they actually mirror the image, so that the picture on the screen can be interpreted in the same way as the image in a rear-view mirror.  For another, many of them seem to super-impose a set of converging lines with distance gradations on them, rather than just giving you a pure image.  So, not exactly an ideal solution, but I’m going to use it nevertheless.  On the right of the image is a “balun”, which converts the unbalanced signal from the camera into a balanced signal, suitable for transmission over long distances via cat5 or cat6 cable.  The balun takes a BNC input and gives an RJ45 output, but the output on the camera is RCA, so I need to use a BNC-RCA converter.

This is a quick mock-up to give an impression of the camera housing.  It’s just going to be a shorth length of 90mm PVC pipe with endcaps, one endcap having a hole cut into it with a clear acrylic window over it.  This will eventually be painted orange like the rest of the ROV.

This picture shows off some of the components of the lighting system, which I’ve not really started working on yet.  At the far left is an Australian 10 cent coin (23mm diameter) to provide scale.  To the right of this is a single 3W LED “star”, which puts out 180 lumens.  I don’t really have any intuitive appreciation for the unit lumen, but apparently this is quite bright.  To the right of this is a special constant-current power supply, or “driver”, for the LED.  The driver can power up to 3 LEDs in series, and carefully regulates the current delivered to the LEDs to maximise their lifespan.  I eventually plan to have two drivers on the ROV, on to the left of the camera housing and one to the right, each powering a cluster of 3 LEDs for a total output of 1080 lumens.  Hopefully this is enough to provide a clear camera image when deep underwater.

and here’s another showing the bilge pump mounted to the grid on the base of the body:

There’s still a long way to go, obviously, but I’m happy to be this far along, which is enough for basic testing purposes.

A few tips for other people building ROVs in (South) Australia:

1. Most ROVs on the web build the mounting grid out of a plastic grid material which is commonly used for two things, diffusing light from fluorescent tubes, or diffusing air flowing out of an air conditioning duct.  It seems that this stuff is common and easy to find in the US, but I had a bit of trouble finding it here.  Major hardware chains like Bunnings don’t seem to carry it.  I had no luck learning where I could get this searching online for things like “plastic diffuser grid”.  The breakthrough came when I learned that this stuff is called “eggcrate” (I was baffled as to why until I found a photo of an old time egg crate, which bears no resemblence to the cardboard cartons you buy eggs in today).  I called a few plastic supply places around Adelaide, including City Plastics, Acrilix Plastics and Menzel Plastic Traders.  All of them knew exactly what I meant when I asked about “eggcrate” and they all sold it.  It comes in sheets which are (from memory) about 120 cm tall and 60 cm wide, and these sheets cost between $30 and $40 at the places linked to above.  One of these sheets should be enough for a few ROV projects if you’re careful with it, so the per-ROV price is even cheaper.  I also read online that you can sometimes buy eggcrate at aquarium supply stores, because people use it to make breathable lids for fish tanks.  I asked a friend who worked at a pet store if she knew anything about this and she didn’t, but it wasn’t a dedicated fish store, so you might have better luck at such a place.  In the end, I didn’t end up using eggcrate at all, because a friend of a friend was able to get me some old bread crates (the kind used in bakeries) which worked well enough.
2. The two places I’ve found which sell bilge pumps of the kind commonly used for ROV projects are Super Cheap Auto (I haven’t looked for one in-store, but you can find them easily enough on their website) and Boating Camping Fishing (and I have bought a pump in-store from my local BCF, and they had a pretty good range).  I tried a Ray’s Outdoors but they didn’t have any.

On a related note, the friend in the friend of a friend chain to my free bread crates recently pointed me to a blog entry by Randal Munroe, of xkcd fame.  It seems that Randal has recently been doing some ROV work of his own.  I was surprised to see that Randal and I seem to have independently come up with more or the less the same control solution – communicating with an Arduino over Cat5 using an ethernet shield.  Randal has gone one step further and has the Arduino controlling the thrusters on his ROV (which are bare motors with properllors, rather than bilge pumps) through a speed controller.  I’m just planning to use some relays for on/off control, at least to begin with.  Anyway, this discovery has at least convinced me that the ethernet Arduino approach to control is genuinely a good idea, so I’m more motivated to go down that route now.

I’m leaving quite soon for a one month long trip (culminating in the Neural Information Processing Systems conference in Vancouver in December!), so I won’t get a chance to do any more ROV work for a little while, but before I leave I’m hoping to get the chance to do a quick bathtub test of what I’ve built so far.  If all goes well, upon my return I’ll buy the 3 other bilge pumps I need to get adequate control and then things should progress fairly quickly!

I’ve been intrigued by the possibilities of print-on-demand book publishing for a long time, and also a fairly obsessive Wikipedia autodidact for a long time as well, so when I discovered this I went into a little bit of a frenzy, where over a period of 2 weeks I composed books on just about everything I’d like to know more about – linguistics, genetics, evolution (and in particular human evolution), neuroscience, Earth sciences, and more.  I absolutely couldn’t afford to get all these books printed (and shipped – shipping costs make the prices of these books not quite as attractive), but to test the service out ordered my linguistics and genetics books.  Including postage they cost me about AU$30 each.  Not super cheap, but given how expensive “real textbooks” are and considering that this system gives you total control over what material the books cover, certainly not bad either.

It took quite a while for them to arive (probably something like 3 weeks), but I was fairly happy with them.  The printing and binding quality seems quite good – the spine of my genetics book was a little crushed at the top, but that’s probably the result of rough transit experiences rather than a manufacturing defect, because the bottom of the genetics book spine and both ends of the linguistics book spine look great.  The system they use to make the books is based on LaTeX, so the pages look quite pretty, although there are some flaws – clearly they don’t convert ” characters into ` and ‘ characters depending on their position, so all the quotation marks look a little bit off.  This is a fairly novice LaTeX mistake and I have no doubt they’ll change it pretty quickly.  It would also be nice if you could choose to have the references at the end of each article excluded.  It’s good to have them there on the Wikipedia website, but in book form having a few pages of hyperlinks at the end of each article is a waste of paper.

The really big issue around these books is just how coherrent a text you can get from concatenating a pile of Wikipedia articles.  My linguistics book was a bit of a grab-bag by design, but I put a lot of effort into planning the genetics book.  You can arrange the articles into chapters, and before getting the book printed I ran my chapter/article structure past a geneticist friend to make sure I was covering the major subjects and arranging things in a sensible order where articles wouldn’t depend too much on information in articles that came after them.  The end result obviously wasn’t as “smooth” as a real genetics textbook (but it was an awful lot cheaper), and there was quite a bit of repetition (including some verbatim repetition where text had clearly been copied and pasted from one article to another), but at the same time at no point did it leave me really confused and scratching my head.  The amount of biology background knowledge I bought to the task of reading the book was very minimal, and I definitely came away from it with what I think (and hope!) is a fairly solid understanding of the basics of the subject (I was able to follow this recent public lecture without any difficulty at all).

All up I’m pretty happy with how the books turned out, and will definitely gradually order the other ones I made.  It might seem silly to some people to spend money on printed copies of material which is freely available online, but I think having a big bunch of related articles in a book you can read on the bus lets you really learn a lot more from Wikipedia than idly reading individual articles online as particular things take your fancy.  It also solves one of the main problems with reading Wikipedia online.

During the time I’ve actually been working on the frame, I’ve been thinking about the (to me) more interesting and exciting stuff, like control.  My original plan had been to keep things extremely simple, and just control the thruster pumps using a block of relays which I sent signals to directly from a control unit on the surface over some ethernet cable.  However, I’ve been doing a lot of reading lately on the Arduino boards and how to do all kinds of things with them.  They are much, much easier to understand and work with than I ever expected and I pretty much can’t wait to buy one and start playing with it.  So I think I’ll put an Arduino onboard my ROV from the start – to begin with I’ll just use it to control the pump relays, but I think I’ll pretty quickly want to start attaching devices to it for navigation and recording data on things like temperature and water pressure.

One really nice thing about using an Arduino for control is that I can put an ethernet shield on it and then control the ROV directly from a laptop, rather than having to wire up a box of joysticks and/or buttons to do control.  I had intended to have a laptop present for ROV sessions anyway (to display camera footage), so this actually reduces the amount of work involved to some extent.  Furthermore, if I can find a cheap IP camera to use instead of a USB webcam, and I can find a very small ethernet hub or switch (this page suggests it may actually be easy to build such a thing using nothing more than some diodes!) I can get away with the one ethernet cable for control and video.  My original plan had been to have one cable for talking to the relays and a separate one for video, which would carry the signal from a USB webcam using an ethernet-USB extender.  Cutting down the number of cables in the tether will reduce cost and increase speed and maneuvarability, which are both good things.

The ideas in the book are well argued and I find myself without any good reason to reject most of them, although the possibility exists that there are better argued alternatives I’m not aware of.  My biggest complaint is that Dunbar’s rhetoric seems to blur the distinction between what language fundamentally does and how we preferentially use language.  I don’t have exact quotes, but there are several places in the book where Dunbar says things to the effect of “language evolved not for the purpose of exchanging information about the world around us, as we so often assume, but for exchanging information about each other for social purposes”.  This phrasing baffles me somewhat, because other human beings are part of the world around us.  Language is, by Dunbar’s hypothesis, for exchanging information about the world around us, it just happens that kind of information about the world around us which we preferentially exchange – and possibly the only kind that our ancestors exchanged – is each other.

This might seem like an odd or insignificant complaint to make, but my motivation for reading Dunbar’s book (and for reading more in general about the evolutionary origins of language) was considering the applicability of Andersonian rational analysis to language.  My recent research has centred around the Uniform Information Density (UID) hypothesis, which is theoretically motivated by the idea that human language is a roughly optimal solution to the problem of high-speed, high-reliability exchange of information (rational analysis in general holds that human cognitive faculties represent roughly optimal solutions to specific problems).  I have heard people question the applicability of this view to language, and in particular suggest that language is not essentially “for” information exchange but rather for various social interactions.  It seems implicit in this line of argument, and in much of Dunbar’s rhetoric, that these are orthogonal or mutually exclusive goals, but after reading this book I think that in fact one is simply a special case of the other, which is good news for rational theories of language.

This reassurance aside, I think the other thing I got most of reading Dunbar’s book was an appreciation for the continuity between the behavioural (and so presumably cognitive) traits of primates, including humans.  Cognitive science seems to be a fairly anthropocentric field – for obvious reasons – but it seems to me like it would often make a lot of sense to take a more inclusive view.  Perhaps attempts at modelling individual differences should also try as best they can to model inter-species differences at cognitive tasks which non-human primates are unanimously considered capable of?

These are all of the objections to integrating evolutionary thinking into psychology that I have either seen or can anticipate, and why none of them hold water:

• “Evolutionary psychology is bad because it will (or might) end up providing a scientific justification for racism, sexism, or some other unpleasant -ism”.  This is a straight up example of the well known is-ought fallacy.  It’s absolutely not a valid argument against EP or anything else.
• “Evolutionary psychology is a junk science full of speculative “just so” stories without any hard evidence”.  This may well be a valid criticism against some, or even many, of the particular ideas which have been developed under the guise of evolutionary psychology, but it’s not a good reason to discard the entire field.  The appropriate response to bad science which combines evolution and psychology is good science which combines evolution and psychology, not a declaration that evolution and psychology shall never meet.   Such a declaration can only be justified by an argument that good evolutionary psychology is impossible in principle.  As far as I know, no convincing argument of this kind has been made, and it seems unlikely to me that one ever will.
• “But, but, but, what about culture?”.  Bringing evolutionary thinking into psychology does not eliminate the possibility of cultural explanations for some phenomena, and in turn the explanatory power of culture does not completely eliminate the need for evolutionary thinking.  Culture isn’t magic: any given cultural influence on thought necessarily has to (i) be an influences on something, and that something has to have existed prior to the particular cultural influence under consideration, and (ii) have bene acquired by some mechanism, which again has to have existed prior to this particular cultural influence.  Evolution is the only thing which can terminate the infinite regress which results from trying to use culture as an explanation for everything.  Biological evolution and cultural evolution are complementary processes, and not at odds with one another.
• “Not everything in an organism’s phenotype represents an adaptation to some function.  The evolutionary process can also lead to traits which are exaptations, or spandrels”.  This is a prefectly valid claim in and of itself (although it’s not necessarily true – I haven’t done enough reading on the “Darwin Wars” to definitively come down on the side of Dawkins or Gould, although I’d love to have done so and fully intend to do so), but it doesn’t really remove the role for evolution in psychology.  It discredits one particular conception of evolutionary psychology, i.e. the conception in which everything is an adaptation.  But all this does is force us to widen our conception of what evolutionary psychology is, from “explaining as much of psychology as possible in terms of adaptations” to “explaining as much of psychology as possible in terms of adaptations, exaptations or spandrels”.
• “The mind is emergent magic!  Chaos, fractals, self-organisation!”.  My characterisation of this school of thought is tongue-in-cheek, but it does represent a perfectly legitimate take on the human mind.  However, once again, it’s not a magic ticket away from evolution.  The full complexity of the human mind may well emerge in some seemingly magical way from the simple, local interactions of individual neurons in the human brain, but that same complexity does not emerge from extremely similar simple, local interactions of individual neurons in the brains of cats and dogs.  Clearly there is some set of preconditions for the emergence of various psychological traits, and if we establish what those preconditions are we will be faced with the task of explaining how evolution drove our brains to meet those preconditions from a previous state which did not.  Evolution cannot have proceeded with foresight toward those preconditions because of the benefits that would emerge from them: each step along the way must have yielded its own benefits, and the story isn’t complete until we know what those steps were and why they happened.

No matter what your particular beliefs are about how the mind or evolution works (well, assuming they’re not dualist in the case of the mind), there’s just no way you can completely separate the two.  “Evolutionary psychology” isn’t some distinct subfield which you can ignore or choose not believe in.  All of psychology is under the influence of evolution, and it is a totally legitimate goal of the science to eventually account for all of these influences.  It’s conceivable that we can completely ignore this part of psychology until “the end”, characterising the functionality of all the various psychological traits without any recourse to evolutionary thinking at all and then tying it all together with an evolutionary story at the end.  But why should we do that?  To the extent that we can without sacrificing scientific rigour, we should try to uncover the evolutionary story as we go.  Not only is it damned interesting, but it can be legitimately used to constrain hypotheses in areas of the science where we haven’t yet made a lot of progress, making it a useful tool.  Besides, it’s just as conceivable that we can’t completely ignore this influence.  If nothing else, I think a basic grounding in the latest facts and hypotheses surrounding the evolutionary emergence of human intelligence should be considered an essential part of a thorough education in psychology.

The show was largely structured around the well known Drake equation, which tries to estimate the number of intelligent civilisations within the Milky Way galaxy, other than our own, which we should in principle be able to make contact with.  It does this by multiplying together estimates of a bunch of relevant terms, namely:

• the average rate of star formation per year in our galaxy,
• the fraction of those stars that have planets,
• the average number of planets that can potentially support life per star that has planets,
• the fraction of the above that actually go on to develop life at some point,
• the fraction of the above that actually go on to develop intelligent life,
• the fraction of civilizations that develop a technology that releases detectable signs of their existence into space,
• the length of time such civilizations release detectable signals into space.

The format of the show was basically to explore the most interesting of these concepts and what we know about them – for instance, how we’re starting to get pretty good at discovering exoplanets, planets outside our solar system, which helps give us an idea of how many stars have planets and what those planets are like, at least in terms of very high level features like size and distance from their sun.  What I found most interesting was the discussion of the 5th term in the Drake equation, which deals with the fraction of planets bearing life where that life eventually evolves to be intelligent.

The show’s discussion of this term was mostly centred around the fact that for intelligence to evolve from unintelligent life takes quite a lot of time, and this time may not always be available.  All kinds of events, ranging from asteroid impacts to strong tectonic activity, can very easily completely or almost completely wipe life off a planet (Earth itself has had 5 major extinction events so far, and some would argue, not unconvincingly, that it is currently going through a 6th, in the form of humans wiping out species at an alarming rate), and if these average duration between these events is shorter than the average time it takes unintelligent life to evolve intelligence, then that suggests that the jump from life to intelligent life will be very rare indeed.

There’s nothing wrong with the above analysis, of course: sufficiently frequent extinction events are both a reality (I recently finished reading reading Bill Bryson’s “A Brief History of Nearly Everything“, which was quite an eye-opener on just how inhospitable Earth is to life on long enough timescales) and a real obstacle to the evolution of intelligence.  But underlying all of the discussion on the show seemed to be an implicit assumption that this was all that was standing in the way: that if there was some particularly lucky life-bearing planet out there which was somehow shielded from asteroids and solar flares and supernovas, and had relatively stable, benign weather and tectonic activity, and basically was left completely unmolested by forces of great destruction, then it would be a matter of certainty that, eventually, intelligence would evolve.  To be fair, I don’t know if the producers of the show or Neil himself believe this, but certainly the show did nothing to explicitly dismiss this notion.

The problem with this is that it’s completely wrong, and yet it is surprisingly often overlooked.  I wouldn’t have noticed this oversight myself if I hadn’t previously read either Steven Pinker’s “The Blank Slate” or his “How the Mind Works” (I forget which it was), which talks about this misconception in considerable detail (I can’t remember whether or not it was in the context of the Drake equation).  Although it’s easy to fall into the trap of thinking that it is, evolution is of course absolutely not some kind of driven, inevitable progression from simple to complex organisms.  It’s about adaption to an environment so as to maximise reproductive success, and unless there is an unintelligent organism somewhere in an environment with the following conditions satisfied:

• intelligence is evolutionarily accessible to the organism (i.e. it already has necessary prerequisites, like a sufficiently complex nervous system, for a few mutations to lead to some kind of intelligence),
• evolving intelligence will give it the organism a significant reproductive advantage over its unintelligent companions,
• and there are no other evolutionary pathways open to the organism which will yield a better ratio of reproductive advantage to “cost” (in terms of energy requirements, etc.) than intelligence,

then intelligence isn’t going to just turn up for the sake of carrying life higher and further.  Those organisms will remain unintelligent, possibly extremely successfully, possibly for an extremely long time, until the next extinction event wipes them out.  Intelligence is not inevitable given sufficiently long time.  It needs a good reason to emerge.

The problem that this situation poses for accurately estimating the 5th term of the Drake equation is that we actually have no idea why humans evolved intelligence.  There are plenty of plausible hypotheses out there, but nothing for certain, and I don’t think there is likely to be anything certain in the near future, given that we know extremely little about the lives of early humans and their ancestors (something else, incidentally, which Bill Bryson’s book gives a good accessible account of) and that we really know extremely little about intelligence (to the extent that there isn’t even a universally agreed upon, objective definition of what intelligence even is).  If we have no idea how we became intelligent, we’re not really in a position to speculate reliably about how likely other organisms are to become intelligent, given the chance.  The 5th term of the Drake equation could, in fact, be arbitrarily close to zero: close enough to zero to completely counteract all the terms in the equation which are very probably quite large.

Of course, it’s by no means a new criticism of the usefulness of the Drake equation to point out that the uncertainty surrounding our best estimates of each of its terms is so great that the final answer can vary by orders of magnitude, and even reach zero.  However, as far as I know, the term relating to the likelihood of the evolution of intelligence is the only one which currently has no reasonable lower bound: you can push it as close to zero as you like and not really reach a point where you can compellingly say “come on, surely it has to be higher than that“.  Which means that no new discovery suggesting that one of the other terms is actually incredibly huge will be sufficient to guarantee a result of more than one.  Which means, somewhat sadly, that perhaps we are much closer to being alone than a lot of people, myself included, have always thought.

On a related note, I recently read this BBC article, which discusses the opinion of one SETI astronomer that we should stop structuring the search for alien intelligence exclusively around the assumption that said intelligence will be biological in nature (which is an implicit assumption – and not the only one – of the Drake equation’s structure) and instead start to consider the possibility that a lot of that intelligence will – in its own version of our own transhumanism movement – have become non-biological in nature; that we should be looking for civilisations of intelligent machines, which are likely to hang out in very different places to intelligent meatbags.  I think this is a fairly persuasive argument.  Eliminating the problem of the mind-blowing slowness of interstellar travel (which is essentially a necessity for a civilisation to be truly long lasting) by figuring out how to transplant our consciousness into machines is probably considerably easier than the alternative of getting around the slowness directly with some sort of sci-fi-esque wormhole stuff.  At the very least, a lot of people who are experts in the relevant field believe that the former may be possible in principle, whereas, as far as I know, the latter is purely speculative.

are capable of diving hundreds of metres under the surface of the ocean and find a wide range of applications in both the commercial world (underwater oil drilling operations being a topical example) and the scientific research community.  They’re fairly pricey too, with even the most basic models – which basically consist of a camera and some light – costing tens of thousands of dollars.  However, a surprisingly large number of hobbyists have managed to build capable “hobby ROVs” for only a few hundred dollars, such as the Seafox, pictured below:

The precise designs of these hobby ROVs varies somewhat, but there are a few things that they all seem to have in common, which contribute to their simple construction and low cost:

• They use standard PVC pipe and fittings as their main structural components
• They use small 12V DC electric boat bilge pump as their main means of propulsion
• They use common, non-waterproof devices like webcams mounted in watertight containers for the onboard electronics

I’ve done some fairly thorough scouring of the web for resources on how to build these things.  As near as I can tell, the hobby ROV movement began, or at the very least was widely popularised by the book “Build Your Own Underwater Robot And Other Wet Projects“, which includes complete designs for two PVC ROVs, the Seaperch and the Seafox (pictured above).  The book is fairly cheap, but there is so much information about these kinds of vehicles online now that you probably don’t need to buy one unless you’re unfamiliar with basic electronics, like using relays – I don’t plan to buy the book unless I run into trouble.  Far and away the best online resource for building hobby ROVs seems to be the Homebuilt ROVs page by Stephen Thone, who has built a number of ROVs, most of them of his own design.  The image of the Seafox above is of the Seafox he built.  Some other decent resources are:

• Hobby Submarines (featuring a slightly modified Seafox)
• Underwater ROV at instructables.com
• How to build an underwater robot, at eHow (the ROV shown here is named “Bob”)

There’s also a Yahoo Group called Robotrov which seems highly regarded in the hobby ROV community, but I haven’t checked it out yet (I’m not partial to Yahoo Groups).

In some ways this is a bit of an odd project for me to undertake, in that I’m not much of a water person.  I’m not afraid of water by any means, but I’m not really into fishing, boating, swimming, diving, etc. like a lot of people who build these things seem to be.  However, while most of my projects are software-based, I have always enjoyed making “real things”, and for a long time I’ve wanted a project I could use to deepen my understanding of electronics (which was probably my first serious hobby when I was a young kid, before I had access to the internet or even computers).  In particular I’ve always wanted to have an excuse to buy and learn to use something like the very popular Arduino boards, but nothing has really grabbed me yet.  ROVs seem like a great candidate for such a project, though, in that they don’t require a lot of space or tooling to construct (I don’t currently have regular access to a large shed or any tools, I don’t know how to weld, etc.), they don’t need to be precisely built (unlike, say, UAVs, which would otherwise be an awesome hobby and for many people are), none of their components require special training or licenses (unlike model rockets), there aren’t any issues with government regulations (unlike the high-altitude balloon projects which are currently extremely popular), and it seems unlikely that simple mistakes could result in catastrophic failures: most ROVs are designed to be slightly positively buoyant, so that a broken tether or flat batteries means the ROV will slowly rise back to the surface of the water, rather than sink to the bottom.

I’ve decided to build a very simple ROV first to get my feet wet (figuratively and literally!), probably just something with the bare minimum number of thrusters to get around, a camera and some lights, before moving onto something more complex.  Rather than strictly following the Seafox design like lots of other people do, I’ve decided to use the “Bob” ROV as a starting point, because its frame/shape strikes me as more efficient than the Seafox, which is really rather chunky.  So today I headed to my local hardware store and bought a bunch of 15 mm PVC pipe and fittings to use for the main frame of the ROV and some 90 mm PVC pipe to use for buoyancy pods, as well as other associated stuff like PVC cement, a hacksaw, sandpaper, some cable ties, etc.  I’ll try my best to make regular posts about the construction process.

After testing the water with a really simple ROV I might have a go at designing something more complicated, from scratch.  I’m particularly interested in building a complex navigation system: GPS doesn’t work under water, since EM radiation at the appropriate frequency only penetrates water a few centimeters deep.  This means ROVs need to rely on things like digital compasses, accelerometers, gyroscopes, sonar and laser rangers to find their way around underwater – lots of fun stuff and plenty of opportunities for learning.

The two directions for NASA are multidimensional, and I think it’s simplistic to simply take a side.  I’m disappointed to see Constellation cancelled, although certainly there were things about it I thought could be better: the DIRECT group’s Jupiter rocket family seems like a better idea to me than NASA’s Ares family, for example.  I think the Obama plan’s focus on privatising the development of launch vehicles makes sense, and stayed up quite late to watch the recent inaugural flight of SpaceX’s Falcon 9, but I wonder about its suitability for manned flight out of Low Earth Orbit: SpaceX have a direct commercial incentive to develop the Dragon capsule and rockets for launching it – ISS ferry missions – but do they have the incentive or knowledge base for something like a Mars mission?  I’m excited about the Obama plan’s push for research on exciting new technology like inflatable spacecraft modules and orbital propellant deposits, but I don’t see why we can’t combine that sort of research with, well, actually going to places and doing stuff.  But I think perhaps the central question in this whole thing, the one which is most important for the long-term future of manned spaceflight, and the one where I am the most baffled by one side of the two camps, is the question of whether we should ever go back to the moon, or simply proclaim “been there, done that!” and head straight for Mars.

I absolutely do not understand the attitude of “we’ve already been to the moon, why go back?”.  Not only does it not make a lot of sense, it also seems to be an attitude reserved singularly for the moon.  Did anybody seriously break this argument out after the first time we reached the north or south pole, or the first time we climbed Mount Everest, or each time we discovered a new island?  Of course they didn’t.  It’s really just a silly argument, and so it’s disappointing that it’s one of the most commonly cited arguments against a return to the moon: probably less common than the old “why spend so much money on space when we have so many problems here on Earth” line, which I feel is effectively dealt with by a combination of pointing out that humanity is actually capable of doing more than one thing at a time, that sometimes the solutions to problems on Earth can be found in space (and this is going to become more true rather than less true in the future as land and resource pressures on Earth mount), and finally that we really can spare the money – the total amount spent so far on the war in Iraq could have paid for a complete repeat of the Apollo program (including R&D costs) with $500 billion left over to spend on the environment, poverty, hunger, education and whatever else you care to mention.

Viewing the fact that we’ve already been to the moon as an argument for never going back confuses space exploration as something done purely for prestige, entirely as a stunt, a game of ticking boxes with no further meaning or purpose.  Admittedly this attitude played a strong role in the original space race, with a desperate desire to show up the commies fuelling most of what NASA did, but in 2010 it’s entirely out-dated and nobody should cling to it anymore.  We’ve been to the moon, yes, but we haven’t yet even scratched the surface of what there is to do on the moon!  We haven’t done a fraction of the meaningful geological research that could be done on the moon: research which can help to improve our understanding of the formation and history of the solar system, including Earth.  We haven’t set up observatories on the far side of the moon to take advantage of a complete lack of light pollution or atmospheric distortion.   We haven’t prospected for valuable Helium 3 in the lunar soil.  We haven’t tried growing edible plants in the lunar soil.  We haven’t tried performing industrial processes on the moon which will work much better and much more cheaply in the reduced gravity.  The list of interesting stuff we haven’t done goes on.  Many would argue that most or even all of the above could be done by teleoperated robots from Earth at a lower cost than it could be done by people.  This is undoubtedly true, but doing it at least partly with people has the benefit of providing much needed practice for the establishment of future long-term colonies on the moon for their own sake.  Seeing permanent off-Earth human presence is essential for guaranteeing the very-long-term survival of the human race, and should always be considered the ultimate goal of manned spaceflight.

Some people who are in favour of off-Earth colonisation would argue that the moon is a bad place to do it.  It’s true that if we just had to pick somewhere in the solar system as a starting point for off-Earth human presence, based entirely on how nice various places are to live, the moon would probably not end up high on anybody’s list.  It has no atmosphere, no magnetic field, very low gravity, not a whole lot of water, and unless you’re in one of a few special places, you can’t rely on solar power easily because night time lasts 14 days.  It makes a lot more sense to head for Mars, and arguably even more sense to head for the atmosphere of Venus (although this idea has a lot less currency amongst space enthusiasts, for some reason).  However, the simple fact is that moving humanity off the Earth is not a simple matter of choosing somewhere to go and then going there.  We have to deal with the practical matters of actually getting and living there.  The moon is 3 days away from Earth using existing technology, meaning that rescue missions and emergency resupplies are actually feasible: contrast this with months of travel for Mars using existing technology.  The radio delay to the moon is a little less than 2 seconds, compared with about 15 minutes for Mars, reducing the psychological feeling of isolation and allowing real time problem-solving assistance from specialist teams on Earth.  Landing on and taking off from the atmosphere-lacking moon is a completely solved problem which we’ve done before, whereas the same problems on Mars are a lot harder and it’s by no means certain the techniques we use for probes and rovers will scale up to vehicles large enough to support a human crew.  Even though Mars is a nicer place to be than the moon, getting to and living on the moon is going to be considerably easier than doing the same on Mars for the forseeable future, and since there are still so many unanswered questions about living off-Earth – what are the long term physical and psychological effects of reduced gravity, of increased radiation exposure, of living so far away from the rest of humanity? – it makes sense to me that we should try to answer these questions in the very near future on the moon, at the same time as we work on getting everything else we can get out of the moon in terms of science, resources and industry.