There are ~150 proteins in the human genome that operate through ~5 processes (some overlap) to maintain and repair DNA damage. DNA damage from many carcinogens would modify individual bases which are maintained through Base Excision repair or Mismatch Repair [2]. Radiation on the other hand (at least the ionizing kind -- X-rays and Gamma-rays) produces free radicals in the cells and can induce single strand and double strand breaks in the DNA backbone. DNA double strand breaks are potentially the most harmful as they must be repaired and in non-dividing cells the probable repair process is the Non-Homologous-End-Joining (NHEJ) which involves the WRN and DCLRE1C proteins which have exonuclease activities which can delete DNA bases from the DNA strands. These in turn introduce microdeletions (or in some cases microinsertions) which can corrupt gene sequences producing downstream problems (unfolded proteins, malfunctioning proteins, diminished protein production, cell death, etc.).

The photolyase enzyme which is involved in repairing thymine dimers (produced by UV radiation) is much simpler than most of the other DNA repair mechanisms. All known organisms with the possible exception of Deinococcus radiodurans and its close relatives repair DNA double strand breaks using similar, potentially genome corrupting, processes because not repairing such breaks is much worse than repairing them and potentially corrupting a small portion of the genome. The problem is that the accumulation of such botched repair processes likely plays a major role in aging. (Think of your body as an running instance of Microsoft Word and cosmic rays are going through your RAM flipping bits in memory. One hour the print function stops working, next hour the copy function stops working, next hour the dictionary lookup stops working, etc. [1] eventually it gets to the point where nothing works and you have to reload it. Bodies are currently not reloadable).

1. We are assuming here that the bit-flipping isn't introducing segmentation violations, etc. Bodies tend to be fairly error tolerant due to the cellular redundancy but the faulty fixups do accumulate over time.
2. All of the DNA repair process have greater or lesser degrees of reliability. Base excision repair is likely to work most of the time. Mismatch repair can be much more a roll of the dice.

> You might suggest that damage to DNA has consequences besides cancer but it actually doesn't, really.

You need to go do some more research. Somatic mutation is probably the primary cause of "aging". There are ~150 DNA repair proteins operating through 4-5 repair mechanisms. One in particular, Non-Homologous-End-Joining (NHEJ) which is the primary repair mechanism for DNA double strand breaks in mammals, particularly in non-replicating cells, involves two proteins the WRN protein and the DCLRE1C (Artemis) protein which have exonuclease activity. That activity will chew up your DNA in the process of repair and introduce microdeletions or microinsertions in the genome in the process of repairing said double strand breaks. Those in turn will introduce frame shift mutations or premature stop mutations or splice site mutations which in turn will increase the probability that you will have proteins in those cells which will never fold properly. Unfolded proteins activate endoplasmic reticulum or mitochondrial unfolded protein responses which contribute to the cell functioning less efficiently and/or committing suicide. Michael Leiber, a Prof. at UCLA has estimated by the time you hit 70 *each* cell may contain ~200 genes damaged by such mutations. Such mutations are cumulative and ongoing.

One might consider oneself lucky if the mutations happen to occur in the less than 5% of genes involved in regulating cell division, cell migration, etc. that are involved in cancer development and progression since it could be a relatively rapid progression to death rather than the slow decline of aging as ones genome in each cell gradually decays.

Because these planes can stay up indefinitely and can fly over specific locations they offer an interesting way to "break" the monopolies posed by the Telephone and Cable companies over most of U.S. and presumably much of the rest of the world. The major problem with satellites is the ground-to-satellite distances and the delays that imposes on "real-world" applications such as telephone conversations or internet access. Low altitude (13-18km [42,000-60,000] ft) is above that at which most jet airplanes fly. Yet one could position planes such as this slightly to the north of most major metropolitan regions and use them effectively as relay towers which would require less infrastructure than standard "cell" phone towers without the delays associated with standard geosynchronous satellites. The planes could be flown continuously out of "regional" airports which have high bandwidth connections to the Internet backbone and provide the high bandwidth up/down-link services to the plane-towers. Interestingly because the plane-towers could be positioned north of most cities one could have mini-dish/phased-array antennas attached to homes, cars, etc. to provide the connection capabilities using the same frequencies currently used for satellite communications (where the dishes face south) [1].

It looks to me like this is an opportunity waiting to be implemented. The cost of the planes is likely to decrease as more nano-technologies become available (e.g. nanotube based wings, lightweight high efficiency solar cells) and electronics advances make routers smaller and more efficient). A JV between Google & Cisco could bring down the monopolies and make the Internet World cheaper for all of us.

1. I'm obviously talking about the northern hemisphere here.

I suspect you come from a different era than that which I am from (1974-1990's computing). I don't own a cell phone or a pad that runs "apps" nor do I have any interest in owning one -- as some reviewer pointed out a few months ago the "Network Computer" was an idea invented by Oracle 15+ years ago. It just took that long for the hardware prices to decline enough and "Javascript" to become popular enough that one could to begin to think about implementing it.

There are times when I like to experience "life" which includes things like reading a real book or smelling the roses and not wondering why I'm out of cell tower range. Nor do my father or aunt (individuals in their 70's and 80's) who like to use their 5-10 year old computers over dial-up lines to stay in touch with people using that primitive medium called email care for "apps". They tend to get frustrated when companies like JetBlue require you to take 20+ minutes to download sufficient Javascript and/or warn about requiring Flash Upgrades to print a simple boarding pass. And if Javascript is so "cool" why am I perfectly happy using Gmail without it? Sure Gmail with Javascript is a bit sexier, but Gmail is the only application I use regularly where Javascript might be desirable. NoScript is the first thing I download followed by Flashblock when I setup a new browser profile.

And when I haven't touched the computer for 12 hours (and it needs to be up because it runs a web server) I don't want my browser -- be it Firefox, SeaMonkey, Opera or Chrome (I've used them all) consuming 30-50% of the CPU time preventing the CPU from dropping the clock speed from 2.8GHz back to 700MHz doing nothing but running garbage collections on a Javascript heap and polling file handles which *should* be inactive. The existing browsers are preventing me from running as "green" as possible and that to me is much much more important than freeing me from hardware I do own (sunk costs) and replacing it with a set of concerns as to why I should be spending more than the cost of a PC on an annual basis to maintain a 3G or 4G connection.

You may have heard of the statement "Information should be free". It isn't if I have to run Javascript on current browsers (or pay Verizon or AT&T significantly more than one would pay NetZero) to get to it.

The speed of Javascript is the *least* of my critera to use in judging a browser (seems like reviewers and developers are operating under some misguided credo where "foreign" software providers running unexamined software ON MY MACHINE is a *good* thing. While open source, an Internet site is free to change their Javascripts at the drop of a hat (unlike an open source browser where one at least some has some community review and reasonable confidence in security/reliability). So any web site which uses Javascript is open to compromise and therefore could become a mal-Javascript distributor.

If the purpose of HTML and Standards is to distribute *information* and not to use *my* CPU cycles or sell me things (aka distribute commercials) I'd be much more interested in browsers that use the fewest CPU cycles in an unused state (or a "used" state displaying static HTML) or reliably restore sessions when requested.

The overemphasis on how fast Javascript runs seems to be due to a lack of serious thought as to how to make browsers better at doing what they were designed to do -- which was *not* to run "web-apps". We used the Internet very successfully for over a decade to provide information -- not to run apps -- if it wasn't (isn't) broken why the emphasis on fixing(?) it?

I note this with an aside that the U.S. Government (NIH NCBI) no longer allows complete access to its *public* databases, e.g. PubMed, by browsers which do not have Javascript enabled. (One is compelled to ask *who* for the most part paid for that information but can no longer access it?).

A "good idea" is something which doesn't break something which used to work just fine when it is supposed to be improving on it.

The article is interesting in stressing the need for a more systematic approach to medicine in the hope of providing both better care and lower costs. That will improve things but it does not solve the fundamental problem.

The fundamental problem is the inherent improper design of biological systems which results in aging. As organisms age components fail and need treatment, repair or replacement. As the fraction of the population which requires these therapies increases costs will increase. Period. There are only two ways to solve this. Agree that because the biological systems are failing and will eventually lead to death we should reduce the level of care provided to these failing systems. Or redesign the systems so that they are more resistant to aging -- i.e. eliminate aging. If one eliminates aging one eliminates a significant fraction of the anticipated increases in the costs of health care.

Now as is usually the case the devil is in the details. What causes aging? Largely the inherently poor design of the system, e.g. energy production methods (the electron transport chain in the mitochondria) which produces free radicals which in turn damage the DNA producing point mutations and/or DNA double strand breaks the repair of which cumulatively corrupts the genetic program of each and every cell in the body until one ends up with either cancer or "aging" [1]. From a programmer's perspective each and every program in the trillions of cells in an adult human's body is becoming corrupted and will eventually fail. We have replacement capacity for some of those programs through our stem cells but those programs become corrupted as well. Until we have the ability to replace or repair the declining genetic programs we will not solve the increasing costs of health care.

Note that one can replace the programs in bulk (organ transplants) and there is an X prize pending for growing replacement organs from ones own stem cells. There are also a number of companies, e.g. Regenexx, BioHeart, etc. working on legitimate autologous stem cell therapies. There are also companies like 23andMe, Navigenics, etc. making personalized medicine available to the masses (so one can known what ones own genetic weaknesses are). And eventually if molecular nanotechnology develops quickly enough and we get real nanorobots like "chromallocytes" the repair of the cumulative DNA damage in each and every cell may become feasible (at low cost without the need for an operating room and a team of surgeons to perform a large organ replacement proceedure).

But until one starts seeing more people point out that the lack of clothes on the emperor (that the real problem is gradual genome corruption and "aging") and the need for a real "industry" to deal with it *and* the political problem that if you solve aging (so people live indefinitely [2]) then one is also going to have to touch the "third rail" of politics (social security entitlements) if one is going to avoid bankrupting nations [3] then speeches such as the one cited will miss the critical issues.

1. This isn't the only way the system is mis-designed. One could argue that the use of free radicals and inflammation by the immune system is questionable. On the one hand it may help to fight bacteria or viruses when one is wounded or otherwise exposed to them but at the same time the same processes probably contribute to heart disease. But heart disease can largely be dealt with through proper diet and exercise, and if necessary relatively inexpensive drugs, the same cannot be said for cancer and aging.
2. Indefinite lifespans are not "immortal" lifespans. Fatal accidents still have a non-zero probability.
3. All of the news debates about medical care costs, national debt, etc. (largely promoted by right wing politicians, new "Tea parties", etc. IMO) *all* ignore the probability that these perspectives largely disappear in light of molecular nanotechnology. People largely don't need Medicare if their genomes were better engineered to last indefinitely. People don't need much trauma related health care if methods of transportation, buildings, etc. were engineered to extreme safety standards (which nanotechnology presumably enables). People don't need social security if 10kg of nanorobots and an acre of land can build them a Sapphire Mansion in a couple of years (they can "live" for free off of the energy supplied by the sun and the labor of the nanorobots). Conspiracy theorists might speculate that the reason there isn't a more aggressive push for the development of molecular nananotechnology is that it would largely make news forums (little or no "bad" news) and/or political forums (and poltical parties and governments in general) historical oddities [4].
4. It has now been 18 years since Nanosystems was published and there is *still* no national or world wide plan (push) to make molecular nanoassembly readily available to everyone.

Depends how "close" to the type of cells required for specific applications you want them to be. The problem is that it is likely that every location in the body where cells replicate has stem cells. Thus extraction ranges from easy to difficult. Skin stem cells (fibroblasts) are easy. Hair follicles are easy. Fat stem cells involve liposuction. Blood stem cells involve a blood draw plus cell sorting (which might get expensive). Bone marrow stem cells require an operation. Stomach, intestine, lung or neuronal stem cells require fairly major biopsy like methods. Now ultimately one can probably turn many (most?) stem cell types into other stem cells for specific therapies. For example, it is likely that one will be able to turn skin stem cells into neuronal stem cells (neurons are derived from epithelial (skin) stem cells during brain development). But the ability to perform these transformations is on a steep learning curve currently and many paths remain a mystery. There are 300-350 cell types in the body so converting A into B for all of them is quite a jigsaw puzzle.

Preservation using current methods would be similar to banking sperm or eggs for in vitro fertilization or banking blood for future operations. Typically one separates the desired cells and freezes them to liquid nitrogen temperatures using a mixture, typically DMSO, to prevent ice crystal formation. More advanced methods are used at labs like Alcor or 21st Century Medicine which are designed to minimize damage to an even greater extent. Preservation requires long term storage in LN2 or temperatures nearly as cold.

While I agree with much of what you have said the general "negative" (we are in a hell of a mess) tone rests upon an important presumption: "That things will not change".

In particular you are assuming that technology will never change sufficiently to meet the material requirements (food, shelter, housing, a number of trinkets (yachts, planes, etc.)) of every human being on the planet. If it does then the debt you are worried about largely becomes irrelevant. The mass doubling time of general purpose nanofactories is measured in hours rather than decades (as one measures human population). If the U.S. Government owns even a small fraction of the IP required to fully develop nanotechnology it will be swimming in cash. Add to that the bond holders will be so "effectively" rich that they could care less about U.S. bonds becoming worthless (if they were to do so). I don't care what my bonds are worth if I live in a "Sapphire Mansion". [In large part the entire system of having to borrow funds from the future to pay for current consumption becomes obsolete.] I know that may seem strange but one really have to have read books like Nanosystems or The Singularity is Near and *really* understand their consequences before one can begin to wrap ones head around this.

In the future material goods become relatively "free" and the only thing of any value is the IP and even that most probably for only a brief period.

I know you probably don't agree. But I was a researcher for TSIN and a Foresight Institute Senior Associate during the late 1990's and know most of the people who developed these lines of thought personally. Assuming we don't undergo a complete financial meltdown (1930's style depression or worse) or get hit by a civilization destroying meteor/asteroid this is going to happen -- the question is simply whether it will happen sooner or later.

Until such time as we have a more complete understanding of parental genomic imprinting and artificial wombs the entire idea of "cloning" is pretty useless. Harry can't benefit much from Harry's clone for probably 10+ years (Harry requiring adult size body parts in many cases) and even then Harry II is likely to object to their use (except for perhaps a spare kidney). The real use for a "clone" is to grow an anencephalic (brainless) body to maturity and then utilize it for brain transplants. I think within the next 10-15 years we will be pretty close to understanding how to rewire the spinal cord (or provide neuro-electrical remapping implants) that will enable this. But if one is talking a twin of a different age thats all it is -- a twin of a different age.

From a genotype standpoint I consider all of the cells in my body to be mostly identical. From the perspective that iPSC cells can be made from them (Biotime and a number of academic labs are fairly adept at it at this point) and if they aren't "identical" they are pretty darn close. The entire "embryonic" discussion becomes irrelevant because you don't have to destroy an enbryo (kill an "individual") to create a clone -- all you have to do is twiddle 4 genes to revert the genomic program to an embryonic "state". So the "only god can create life" fan club(s) have fallen into quicksand where the justifications and rationalizations are going to seem increasingly distant from realities which can be scientifically demonstrated. Anyone who has ever owned a DNA synthesizer (as I did 15+ years ago) has known that "creating life" has been more of a cost/desire/need issue rather than a feasibility issue.

While many of the current stem cell clinics overseas do fall into the snake oil category one should not cast out the baby with the bathwater. If one understands the following probable guidelines, then one may be able to navigate the field.

1) Non-autologous (non-self) stem cells are likely to be extremely problematic for therapeutic purposes because there have been a number of reports showing that the immune system will eliminate those cells over time (without immune system suppression). If you view them as "organ transplants" from other individuals which require drug protocols to suppress Natural Killer Cells and other arms of the immune system with significant probabilities of rejection then therapies which involve non-self embryonic stem cells or non-self iPSC cells might be useful. But they are never going to be a "good" solution. (This means that the debate over "embryonic stem cells" which blocked a significant amount of progress in stem cell research in the U.S. over 8 years was useless "noise".)

2) Autologous (self) stem cell therapies *are* useful. One already effectively uses them in cases of storing sperm, eggs, blood and skin for future use. There have been common uses for decades such as for blood storage before a major surgery, growing skin grafts for burn victims breast reconstruction surgery, etc. Common heart bypass operations are another example of transplanting tissue from one region of the body to another. There has been a "Holy Grail" search to obtain embryonic or totipotent stem cells over the last decade due to the press/hype that they can "grow into any tissue". While we have the knowledge to do this for some tissues we do not have it for many more. Indeed one doesn't need totipotent cells for most therapies. Partially differentiated stem cells which are very close to the target tissue types will work as well, perhaps even better, than totipotent undifferentiated cells.

3) While injecting stem cells into the blood and hoping that they end up in the right place and will do the right thing works in some cases (e.g. bone marrow transplants) it is *not* likely to work for most applications of stem cells. Each type of therapy where stem cells may be used is going to have to be a precise tissue specific (heart, brain, lung, hair follicle, joint, tendon, muscle, blood vessel, skin, etc.) therapeutic protocol. That is why one is likely to see dozens of companies with specific expertise and not "one size fits all" solutions. There isn't going to be a "magic bullet" -- therapies are largely going to have to replicate, typically through cell culture in a laboratory, many of the natural processes which occur during fetal development in order for therapies to be effective.

4) There are on the order of 2300+ clinical trials in stem cells going on around the world (according to the NIH clinical trials database). Some of them are likely to be useless. But some of them might be quite useful.

5) There are companies in the U.S. that are doing autologous stem cell therapies with a fair amount of success. Three that I'm aware of are VetStem, Regenexx and BioHeart.

6) There has not been a widespread understanding yet within the stem cell R&D and therapy communities that stem cells *do* age. Simply, stem cells accumulate mutations in their genetic code with age which will cause them to function less well if sourced from elderly individuals compared with young individuals. [Everyone should have cryopreserved pools of stem cells when they were 10-15 years old.] So a stem cell therapy that might work very well in a young individual (say 20-30) may not work as well (or at all) in an older individual (say 60-70). There are methods that may be used to address this problem (disclaimer: I am the author of a pending patent on one of these methods) but they have yet to be put into practice by *any* stem cell clinic to the best of my knowledge.

So one can "dis" current stem cell therapies as being snake oil, often with some basis for the feelings, but you should not "dis" the concept. Everyone probably has quality stem cells within their body and these could probably be used with great success in treating severe accidents and/or aging. IMO, for the next 15 years or so high quality autologous stem cell therapies will likely provide the best path for retarding aging and extending functionality for the elderly. Sometime, probably 10 to 20 years from now, if R&D is supported sufficiently, we should be able to start replacing our own cells and eventually the DNA in those cells with better operating systems.

It should be pointed out that Google's promotion of Javascript and its use is self-serving (if their apps don't run using Javascript then I'd imagine that they don't run at all). It also goes without even a very long discussion that promoting Javascript is potentially promoting security holes as well as excessive CPU use (and thus the browser using more electricity and being non-Green) as well as network overhead (delaying the network for everyone).

Now, if Javascript were used intelligently, i.e. no code is transmitted unless the user requests it, no code executes unless the user allows it and web sites were designed to be be fully functional *without* Javascript then its promotion might be reasonable. But that is hardly the case for the web as it sits today.

HTML is a *display* language. It exists to distribute information and there are many many Internet users who are very happy with that use. I don't need any part of that "interactive experience" that some people seem to desire. I especially don't need or want costs or risks imposed on me by web designers without my permission. As Joe Friday used to say, "Just the facts, Mam."

If Google spent half as much time improving the "display" aspects (speed, efficiency, power use, etc.) as they spent on improving Javascript we would have a very cool browser in chrome. But that does not appear to be the case.

Astronauts are not "mass produced". They are a rather select group of highly trained individuals. The people who train them are not "unskilled". They require the support of a *lot* of computers to both design their spacecraft, build them and operate them. And to a large extent computers are now built by computers at the design, chip making and testing phases.

In case you haven't priced it out recently the cost of a whole rack of microprocessors, i.e. a supercomputer, is a heck of a lot cheaper than a highly trained human astronaut.

I suspect when Wernher made that statement he had no idea the extent to which modern society and indeed space development and exploration would become dependent on mass-produced non-human computers. (A close friend of my fathers was one of the people who worked on the design of some of the first integrated circuits which would eventually be used in some of the Apollo electronics.) The first mass produced microprocessor, the 4004, was released in 1971 when Wernher was 59. Wernher von Braun was dead before the 8086 was released which lead to the PC era). Opinions when may be correct in some contexts may not be correct in others.

The satellites and the Mars rovers are not wholly "remote controlled" -- they are running "limited intelligence" programs that allow them significant amounts of autonomous operation. I'd put them as comparable to perhaps 4-8 year old humans in terms of "autonomous" operation. They needed external management and contributions from time to time. And as I recall Apollo 13 would fall into a similar category even though it had adult *human* operators.

As far as "colonizing" goes -- there isn't a "hospitable planet" in the solar system. In order to make Mars hospitable you need to terraform it. In order to terraform it you need molecular nanotechnology. If you have molecular nanotechnology you might as well disassemble it and contribute its mass to the Matrioshka Brain. If you really want to colonize someplace alien but hospitable there are places like Antarctica, 1+ mile deep in the ocean, the cone of an active volcano, a lot of mountain peaks. Some of those have been colonized but not *really* since they have access to regular support on pretty much an "as needed" basis. If you want to *really* colonize some of those places simply send a team of humans there and don't provide them with any external support unless there is a life or death situation (and even then you are probably breaking the game rules). One could easily make up situations here on Earth that look like Moon, Mars or even Europa colonization efforts *WITHOUT* the expense of having to design new rockets, haul mass out of the Earth's gravity well, insert it safely into foreign gravity wells, etc. The "colonization" part is one aspect of the problem. What resources you do it with can be artificially constrained if you know enough about where you are starting from and where you are going to end up. If there is no ice on the South Pole at the moon then human colonization becomes an much different exercise than if there is. But we could fairly easily play out both scenarios here on Earth.

If on the other hand, colonization which is extremely difficult is your cup of tea, might I suggest a colony on the surface of Jupiter.

I'm not talking about REM sleep. I'm talking about physical damage to DNA caused by ionizing radiation (gamma-rays & X-rays where the photons have enough energy to split water molecules) which produces hydroxyl radicals in the nucleus that attack the DNA. Similar but more extensive damage is caused by heavy ions (charged Fe, C, O, etc. that stream through space -- and ultimately contribute to cosmic ray showers). The only way to shield from the high energy photons is a lot of mass (e.g. lead or an equivalent mass of liquid/solid H) [what one wants is "nucleus" density). In a pinch one could get by with a lot of water/ice which has other uses and probably has to be carried along unless you have a completely closed recycling environmental system with zero losses.

I was quite surprised that current NASA policy limits total space time of astronauts so as to *only* increase their lifetime cancer risk by something like 4-6% -- and that is for non-lunar flights within the magnetosphere (which does a lot of the shielding for us). Presumably if one is willing to sit on top of tons of rocket fuel one can view future cancer risk as acceptable. But that wasn't considering months or years of total time in space.

And while yes, the human body is capable of a lot of self-repair and most robots are not but that doesn't mean that they cannot be designed with sufficient redundancy (4 antennas instead of 2, 8 wheels instead of 6, etc.) or have "spares" available, etc. In case you haven't noticed a *lot* of what has been going up in the Space Shuttle recently has been spare parts to extend the lifetime of the space station. A properly designed robotic colony would have a robot replacement part warehouse just like any factory on Earth which requires 24/7 operation. And you might notice that on the Apollo missions I don't think there was a physician on the crew manifest nor was there an operating room available for serious injuries. So the repair capabilities for humans in space are somewhat limited compared to what they are in developed societies here on Earth. No holographic doctors at the Moon Colony.

All I can say is "Its about time." The human body is not designed to operate in space, indeed almost all biological systems on Earth that reside under nice "shields" including the magnetic field, the atmosphere, the ozone layer or even the oceans and they were not designed (evolved) to withstand the hazards of space. Ignoring minor topics like micrometeorites and the lack of atmosphere one has the ongoing problem of radiation exposure. Humans for example have 150-200 genes in the genome (~1%) whose purpose is to repair DNA damage. It does not do so reliably (so radiation causes gradual genome decay). And although one may develop "shields" this makes activities by humans in space inherently more expensive than using the right "organism" [1]. Anyone aware of robotics research knows that the Japanese are pushing this forward at a very rapid pace. Presumably much faster than one can push forward human "evolution" [2].

Yes humans can engineer suits, habitats, shields, rovers, etc. which would allow humans to operate in such alien environments. But *why* do this? One has to remember that the "moon rocks" were brought back to Earth for analysis. We have to develop the remote robotics operations capabilities for exploration anyway [3]. Lets do it for the moon first.

If people want to go places to say "I have been there", then fine let them pay for it (as private citizens or organizations) -- just don't expect all the rest of us to pay for your expensive vacation. The robotic development of the moon could serve as a prelude for human colonies there (to preserve humanity from terrestrial impacts) or taking vacations there. The moon is close enough that round trip radio can be used to control or reprogram robots in the event of complex/unforseen situations (remember we reprogrammed the Galileo mission when it proved necessary). The "nightmare" scenario of robots evolving into autonomous entities (a new robotic species) only arises when one is dealing with situations where remote control and/or reprogramming are not possible and one has designed the robots both self-reproduction and intelligence enhancement capabilities -- and I think we are still quite some distance from those achievements.

1. References to using a hammer as a screwdriver apply when using humans in space. Astronauts require additional tools and training to work in space. Instead design the systems to be easily maintained and repaired by robots in space.
2. Ideally if one wanted humans to live in space one would use genetic engineering to produce humans which were radiation tolerant. This not only has benefits from a space exploration standpoint -- such humans would likely have reduced cancer rates as well. But such developments are at least a generation away.
3. I have yet to see a single proposal for a single human "submarine" or a human colony to explore the oceans of Europa to search for life or provide a humanity "safe room".