Just beyond the edge of the usual

 kw: book reviews, science fiction, short stories, ekumen series, space travel, anthologies, collections

I read some of the stories collected in The Birthday of the World and Other Stories, by Ursula K. Le Guin, when they were first published in the middle 1990's. It was a rare pleasure to re-read them, and to get to know their companion pieces, with the perspective offered by thirty years of personal experience and the dramatic social and political changes that have occurred in that time. These stories represent Ms Le Guin twenty years into her prolific career. This collection was published in 2003.

Seven of the stories (maybe only six, by her assessment in the Preface) take place in her speculative universe, the Ekumen, in which all "alien" races are descended from the Hainish on the planet Hain, from which numerous planetary societies have been founded. Sufficient time has passed that quite different, even extreme, societal and physiological variations have arisen. This affords the author a way to explore societal evolution among beings that are at least quasi-human. It removes the difficulty of dealing with totally alien species.

The story I remember best is the opening piece, "Coming of Age in Karhide." Although the Ekumen is mentioned and a few Hainish dwell on the planet, the story focuses on the experiences of a young person approaching "first kemmer", a span of a few days or weeks in which the sexless body transforms into either a male or female body, the newly-sexed man or woman has promiscuous sex in the kemmerhouse, and may become a parent; it can take a few kemmers (which I translate internally as "coming into heat" the way cats, dogs and most animals do) for a female to become pregnant the first time. During each kemmer, a man may remain a man or change to a woman, and vice versa.

The author passed away in 2018, just as "trans ideology" was garnering political power, primarily in "blue" states. I wonder what she thought of it. Thankfully, the ideology is fracturing and I hope it will soon be consigned to the dustbin of history. At present, roughly a quarter of American adults appear to genuinely believe that complete transition is possible. It isn't, "sex reassignment" is cosmetic only. It is only for the rich, of course; transition hormones cost thousands, and the full suite of surgeries costs around a million dollars. The amount of genetic engineering needed to produce a quasi-human with sex-changing "kemmer", should any society be foolish enough to attempt it, would cost trillions.

Other stories in Birthday explore other sexual variations, and the societal mores that must accompany them. These are interesting as exploratory projects. They were written shortly after the death of Christine Jorgensen. Ms Jorgensen was the first American man (but not the first worldwide) to undergo complete sexual reassignment surgery, in the early 1950's. Subjects such as the surgical transformation of the penis into the lining of a manufactured vagina, without disrupting blood vessels and nerves, were actually published in formerly staid newspapers! 

To my mind, in America at least, Ms Jorgensen is the only "transitioner" to whom I accord female pronouns. She transitioned as completely as medical science of the time allowed (and very little progress has been made since). She became an actress and an activist for transsexual rights (she later preferred the term "transgender". I think she learned a thing or two). She even planned to marry a man, but was legally blocked. She intended to enjoy sex as a woman would. Maybe she did.

The last piece in the volume, "Paradises Lost", takes place on a generation spaceship. Population 4,000, strictly regulated to match the supplies sent on a journey that was intended to require more than 200 years. The religious politics that threaten to derail the enterprise don't interest me much. Of much more interest: the mindset of residents in the fifth generation after launch, after all the "Zeroes" and "Ones" have passed away, expecting the sixth generation to be the one to set foot on the new planet; and the way the "Fives" react to their experiences on that planet after an early arrival (sorry for the spoiler).

We are only in part a product of our ancestors' genetics. Much more, we are a product of the environment in which we grew up—which is only in part a product of our ancestors—, in which we had those formative experiences that hone our personalities. While all the stories in this volume explore these issues, "Paradises Lost" does so most keenly.

The work of Ursula K. Le Guin stands as a monument to speculative thinking in areas that few authors of her early years could carry off.

To Jupiter in a Week?

 kw: analytical projects, space travel, solar system

I began reading a bit of space opera from the early 1950's, in which a space pilot goes from Earth to Jupiter in seven days. I wondered how that would be possible. My first thought was, "Jupiter is around half a billion miles away. What does it take to speed up to around 70 million miles/day (~3 million mph)?"

For perspective: About fifteen years ago, the New Horizons spacecraft was launched from Earth and boosted to a speed of about 45 km/s (about 100,000 mph). Thirteen months later it approached Jupiter, still going just under 20 km/s, and was directed into a slingshot flyby that boosted its speed to about 22.5 km/s.

From this point we go metric. Jupiter's distance from Earth varies between 588 and 968 million kilometers (Mkm). For what it is worth, when Earth is at quadrature with Jupiter, one can gain an extra 30 km/s of takeoff speed, and at that point the distance is near the average of about 780 Mkm. For this analysis I'll be dividing by 7 and by two numbers divisible by 3, and to have an even-numbered result, I'll pick a distance that is divisible by 126 million (126=9x7x2). I chose 126x6 = 756 Mkm.

First simple analysis: 756/7 = 108. Thus, average speed needs to be 108 Mkm/day or 1,250 km/s. That's almost 28 times as fast as the starting speed of New Horizons (Clearly, science fiction writers in the pre-Sputnik days expected great advances in rocket fuel technology). Suppose the rocket can accelerate at 1G for as long as needed. How long does it take to get up to 1,250,000 m/s?

Basic velocity formulas:

• 1G acceleration (a) = 9.8 m/s²
• Velocity (v) = 9.8*t m/s
• Distance in time t = 4.9*t² m

Turn the second formula around: t = v/9.8, which comes to 1,250,000/9.8 = 127,550 sec = 35.43 hours. It takes about a day and a half to get up to speed. Without going into detail, this means that actual travel time would be more like 8.5 days. But this puts us in the right ballpark.

Let us figure what acceleration is needed to go half the distance at constant acceleration, then turn around and slow down in the same amount of time and distance. Half the distance is 378 Mkm. Solve the third equation for a, the acceleration needed to go 378 Mkm in 3.5 days, or 84 hours, or 302,400 seconds: a = 2*dist/t², which comes to 8.27 m/s². That is about 0.84 G. With that level of acceleration, our pilot can have the comfort of a near-1G environment for the whole trip, except for turnaround at the midpoint, and other maneuvers at both ends. Peak speed would be 8.27*302,400 = 2.7 million m/s or 2,700 km/s, or more than twice the average speed.

So there we have it. We just need a fuel-&-engine system that can accelerate at near-one-G for a total of a week, and repeat the performance for the return trip.

A secondary consideration is, what would be the consequences of hitting a dust particle, or worse, a sand-size particle, at a speed of 2,700 km/s? An average grain of beach or dune sand is half a mm across and weighs about 180 micrograms (µg). 180 µg is 180 billionths of a kg, the unit we need to calculate energy. Silt particles are 1/100 the diameter and weigh one millionth as much, or 180 trillionths of a gram.

Let's start with a sand grain. Kinetic energy E = m*v²/2, or 0.000 000 18*(2,700,000)²/2 = 656 thousand joules; a joule is a watt-second, so this comes to 182 watt-hours. This is the energy of a 1 kg mass at a speed of 1,150 m/s, a little faster than the bullet from an AR-15 rifle, but that bullet weighs only about 4 grams. This sand grain deposits the energy of 250 rifle rounds in an area half a millimeter across. That would melt a chunk of armor plate and make a hole you can stick your finger in. The ship's pilot would feel a bit of a jerk from the impact.

A grain of silt or dust, with one-millionth the weight, has one-millionth the kinetic energy, which comes to 2/3 of a joule. It doesn't sound like much, but that's the energy of a BB dropped about a foot. You'd hear it. It would strike off a bit of material, which a BB wouldn't do. Intermediate-sized grains would do correspondingly more damage. Sand size grains are very scarce in the asteroid belt, but silt-size grains are probably abundant enough that the wear on forward armor would be significant.

So, as enjoyable as such tales are, with people bombing around the solar system as though one were driving from Idaho to Florida, there's a lot of reality in between where we are now and the technology needed to accomplish it.

First contact - with AI

kw: book reviews, science fiction, space travel, space aliens, artificial intelligence

Considering recent titles by Ben Bova, I figure that his new novel Survival is one of a series, probably the second or third. Very generally, humans have been contacted by a starfaring machine culture that they call the Predecessors, an altruistic one that is attempting to contact as many planet-bound cultures as they can, to help them prepare to survive a "Death Wave" that is spreading from the galactic core. Periodic cataclysms there emit enormous waves of gamma radiation that scour all the planets in a galaxy of organic life, and also any "machine life" that is insufficiently hardened against the radiation.

Much of the dramatic tension in the book, aside from a couple of love stories, concerns the contrast between the Predecessors and another machine culture on a planet about 2,000 light-years toward the galactic center from Earth, dubbed the Survivors. The Survivors are not altruistic. They are motivated only by a drive to survive that was built into them by the organic beings that first created them and then perished in an earlier death wave. A human ship sent to warn the Survivors is held captive by them. They do not wish to receive such help, having survived prior death waves, and they are supremely indifferent to the fate of the organic life on their planet, even though they had a hand in preserving remnants of earlier biospheres, and re-instating them.

It would give away too much to describe more of the plot. Of course, this would not be a Ben Bova novel if the humans didn't find a way to influence the Survivors.

I am interested in decision making, by men and machines. A number of psychological and sociological studies in the past couple of decades have demonstrated that an emotionless, Spock-like hyper-logical being would actually be crippled when it came to deciding between competing alternatives. People who have suffered injuries that disconnect their intellect from their emotions, or that destroy their emotional centers, are incapable of making decisions. It seems that we need the ability to like or even love one thing more than another. Emotion is not contrary to logic, but in some way amplifies it.

We were, or at least my generation was, taught that our brains evolved in layers, with an entirely reactive "reptile brain" or even "fish brain" overlain by an emotional "rat brain", all wrapped in a cerebral cortex, the "higher brain" in which free will, creativity and intelligence resides. Further, if we learned a smidgen of endocrinology, we find that emotion is a largely bodily function, mediated by hormones and other small molecules that motivate us, or its opposite, in response to many kinds of stimuli. The reality is not all that simple. Disconnect the cortex from the inner layers, and reasoning spins along without having any "hooks" to pick one alternative over another.

The "modern" (50-70 years) efforts to create Artificial Intelligence (AI) comprise two branches. The engineering branch includes various attempts to replicate human reason by finding all the rules we follow. The "poster child" for this branch is the Expert System, much touted 20-30 years ago. Its best-known example was the Caduceus System for medical diagnosis. It was supposed to be able to ask a doctor or patient a series of questions and then produce a differential diagnosis of any condition. It could eventually diagnose about 1,000 conditions, a small fraction of the total. As is typical of the field of AI in general, it had a few dramatic successes amidst a great number of equivocal results and a large mass of failures.

The heuristic branch of AI includes neural nets and machine learning systems. A neural net is a framework that is thought to (very roughly) represent natural networks of neurons, and while it can be implemented in hardware, it is most often emulated by software running on a multi-core processor. A machine learning system can be based on a neural net, or on other technologies that are being tried on a rather empirical basis, almost trial-and-error. The Watson system, which won a round of Jeopardy against two very talented men, is the current exemplar. I doesn't make the news much these days. It cost billions to develop, and a number of applications (besides winning game shows) are still being developed. It has been 7 years since the Jeopardy event. So far as I can find out, its main strength is parsing and answering questions posed in natural language, presumably orally, and it is mainly being used for decision support in the treatment of lung cancer.

Many of us now encounter AI in the form of Siri, Alexa, Cortana or a few other voice avatars of our smart phones and "thing in the den" systems. They can indeed parse our vocalizations into text, and then the "big computer in the cloud" can come up with an answer for us. A few years ago a short article in the endpapers of Scientific American touted a machine system that supposedly exceeded the human brain in processing speed and memory capacity. Just a bit of miniaturization is needed before such a "machine brain" can be installed in Robby the Robot, however: the system requires a 9 megawatt power plant to support the electronics and the cooling systems, and fills a warehouse. Can we expect technology to advance until such a system is lunch-pail size and runs of a lithium battery? Can Moore's Law (very roughly: capacity tends to double about every 2 years) deal with this?

Wouldn't you know it, Moore's Law ended about 15 years ago with the development of CPU cores (because more than one CPU is now put on a chip) that run in the 3-4 GHz range. That has been the limit. I built the PC I am using about 8 years ago, to be a middle-of-the-road desktop system. It is still a middle-of-the-road system. In the 1980's a machine with this level of compute power was called a supercomputer. Today's supercomputers are enormous arrays of 4 GHz multicore processors running special software so they can effectively communicate and thus break up a complex process into numerous subprocesses. Had Moore's Law continued from 2005 until today, a single-core processor running at a clock speed close to 1 THz would be the basis of most systems (and phones, etc.), and a large chip holding up to 1,024 cores would form the basis of supercomputers that would fit in a filing cabinet-size unit, consuming no more than a few hundred watts.

Will quantum computing re-start Moore's Law where it left off? So far, it is a great deal harder to take advantage of quantum coherence and decoherence than anybody predicted in the 1990's when "quantum computing" was coined. Without that, however, we have little hope of developing a "machine brain" to rival the mammalian brain for its combination of size and capacity.

And we still have no clue how to even define consciousness, let alone reproduce it. Every SciFi story about artificial consciousness either finesses it with "it just happened when we put together enough circuits", or doesn't try to describe its workings at all. Based on the studies mentioned earlier, a big component of consciousness is our emotional response system(s). We really don't understand that, and until we do, it may be impossible to develop a Watson-like "decision support system" into an effective "decision system".

Still, a well-told tale of how we might interact with any machine civilizations out there is a welcome diversion from the "organic" aliens we usually encounter. It gets the brain cells working in a new direction or two...a good thing.

Leapfrogging NASA?

kw: book reviews, science fiction, space travel, space policy

Here is an idea for you. The US government has no stomach any more for crewed space travel beyond "low earth orbit", meaning inside the inner Van Allen Belt, at altitudes well below 1,000 km. Imagine persuading twenty or so of the top billionaires to contribute a total of $100 billion to fund a private program to go to Mars. That is the premise behind Ben Bova's latest book Mars, Inc.: The Billionaire's Club. It is no spoiler to tell that the book ends with the ship's launch. The interesting ideas come throughout, as the protagonist, one Art Thrasher, herds together the billionaires, NASA, and a national government or two while fending off hostile takeovers of the company, sabotage and other assorted obstacles, and chases every skirt that crosses his path in the meantime.

Let's consider the finances. Thrasher gets each of twenty billionaires to contribute $1 billion yearly for five years, for a total of $100 billion. It seems he is counting on much greater efficiencies than past programs. The Apollo program cost $20 billion in the 1970s, and if you inflate by 6 (check the CPI calculator for the factor from 1970 to today), it would cost $120 billion. That was to go to the Moon six times. Government estimates for a Mars program range from $1 trillion and up. Of course, the cost to get there and back the first time may be less than that, but $100 billion is wildly optimistic.

Bova imagines using nuclear propulsion (and has a lot of fun with Thrasher getting permission to launch one!), using standard figures that it is more than twice as efficient as chemical propulsion. It is, but if the shielding needed to protect the crew doubles the weight of your craft, it is a wash. This isn't mentioned.

An element I found fascinating is a logical extension of Virtual Reality as we presently know it. Currently affordable equipment can handle vision and hearing quite well. Getting tactile feedback is still in the research stage, and a few primitive versions of the Haptic Glove can be had at steep prices.

Side note: a haptic glove uses tiny vibrators and other wiggly items distributed over its inside surface, wired to a controller that connects it to the computer. It simulates the feel of virtual objects. Simulating heft, body, and mass resistance are separate problems entirely: The glove might let you feel the texture a barbell's handle, but it can't exercise your arm while you "lift" it. Nor can it keep you from closing your hand beyond the surface of that virtual steel handle. There are no prospects for a haptic "Y at home".

Now imagine a haptic body glove. In the novel, Art Thrasher complains that putting one on is like climbing into a stiff Brillo pad. That's probably apt. But Bova's notion is, we may have watched Neil Armstrong land on the moon on our TV sets (a facet of the story no science fiction writer had predicted), but for Mars exploration, how about sending Virtual Reality signals back so that people can experience what the explorers experience? Selling the VR equipment is posited as a funding source for ongoing Mars exploration.

Hmm. Millions and millions of people watched the Apollo 11 landing. Hardly anyone watched A17. I wonder who'd have watched if they'd known it would be the last in their lifetimes? It has been just over 41 years…

It is in the nature of such a book that it becomes a political thriller. Most such turn me off, big time. But Bova keeps the overt politics to a minimum and lavishes the technical, as much as he can. Now, if somebody can just come up with a propulsion system that is double again as efficient as thermal-nuclear, to get people to and fro in a month instead of half a year. We can only dream.

A Dyson hemisphere

kw: book reviews, science fiction, space fiction, space aliens, space travel

In their first collaboration, Larry Niven and Gregory Benford have come to lead that subgenre of Science Fiction that combines hard science, some blue-sky projections thereof, and believable sociology of both human and alien societies. In the case of Bowl of Heaven, the hard science keeps all speeds below that of light and accepts certain other known limitations of physics, the projections (or speculations) push engineering to the scale of a solar system and also posit a ramscoop that uses superconducting magnetic fields a few thousand times greater than any so far known, and the sociology involves a dozen or so humans confronted by not just one or a few quite alien species, but a profusion of them, in a colossal engineered ecosystem.

Most SciFi aficionados know the concept of a Dyson Sphere, the product of a society that captures all the radiation of a star as its energy source. Though Dyson first conceived of a hollow sphere, the concept was soon modified to encompass myriads of large, stellar-light-capturing orbital habitats in a thick shell about the star, sufficient to block all or nearly all of its light, and emitting waste heat primarily at wavelengths between 8 and 20µ (the human body's thermal radiation, at 310K, peaks at 10µ). So far, no deep-infrared stars suggestive of such structures have been observed. The orbital mechanics of such a system are formidable, and collisions might be so frequent as to make the scheme impracticable.

Niven's best-known foray into the partial Dyson Sphere arena has been the famous Ringworld series. Now we have an even more ambitious engineering project: Build a hemisphere centered on a flare star (a late K or early M star that tends to have a strong stellar wind), that supports many (quadrillions, I suppose) steerable mirror segments. Its radius is roughly an AU (150 million km). A wide ring at the equator supports a habitat with the area of many trillions of km², and the structure rotates to produce centrifugal "gravity" in the habitable ring. There is a hole at the center (the rotational axis of the hemisphere) with a special function. The mirrors reflect the star's light to focus on an area at the "rear" of the star (we can presume its axis of rotation), heating it and focusing its stellar wind into a jet that passes through the hole in the hemisphere. This begins to drive the star. Some sort of engines in the hemisphere counteract its orbital instability until the star begins to accelerate sufficiently to closely balance the tendency of the hemisphere to fall inwards. Then the job of the engines is quite a bit easier, or at least less energetic. Now you have a "ship" that is similar in size to the orbit of Earth or perhaps Mars, that can cross interstellar space over a span of millions of years.

This idea by itself could be fodder for a simple high-concept novel. For Niven and Benford it is mainly backdrop. Put it out there, make it a few tens of millions of years old, populate it with a cadre of large, birdlike alien species and an uncountable number of "adopted" alien species whose members they have plucked from star systems as they swung by in ages past. Then add US.

A ramscoop from Earth, bearing colonists heading for a star they've named Glory, catches up with this star-centered Bowl. Now, we all know that paying a visit to aliens who can engineer on such a scale is quite foolhardy. But it happens that the colonists, most of whom are in frozen sleep, have a problem. The small "awake" crew has discovered that the ship's top speed is a few percent low. Low enough that they can't keep a crew awake and alive long enough to get to Glory. They figure the Bowl might be able to supply them with materials they can use to replenish their stores, so they do pay the ill-advised visit, and of course the landing crew is partly taken captive and partly escapes to re-learn their Boy Scout skills as they flee hither and yon, evading capture while they learn what they can about the Bowl and the habitat.

I have wondered in the past just how big a spinning structure could be, to produce about 1g of apparent gravity. It turns out that the stress intensity for 1g of centripetal acceleration increases linearly with radius, such that the strongest known steel could not produce 1g when the radius is greater than a few hundred meters. Perhaps some kind of carbon nanotube assembly could hold together a structure of a km or so diameter. Both Ringworld and the Bowl would require materials with a tensile strength a few million times greater than any known. However, I was able to keep such considerations from marring my enjoyment of the book and its concepts, and I trust so can most SciFi readers.

A great deal goes on in this 400-page book, as we glean insights into the various cooperating "big bird" denizens and some of the Adopted species, and as one human group begins to learn to communicate with their "hosts" while the other searches for understanding and some kind of bargaining leverage. Here, the volume ends. I suppose a trilogy is planned (though the authors promise but one sequel, Shipstar).

The possibilities of quite distinct psychologies that the authors explore in the big birds are fascinating. Is our human Bicameral Mind going to be a handicap or a detriment, compared to their more unified psychology? It makes me wonder if the future volume(s) will explore the possibility that human psychology could become more unified, making our "unconscious" more consciously accessible.

There is a character, Fred, that I found myself identifying with. He is socially awkward but totally at ease with machines and computer code. In a conversation he describes his problem-solving technique, which takes advantage of sleep, and I was saying, "Yes! That's just what kept my programming career going for 4 decades!". I figure that either Niven or Benford must do this, or they know quite well someone who does and has described it. It is comparatively rare as an explicit technique, though many people have experienced waking up with a worrying problem solved.

Now I have my marching orders, to track the progress of the next volume, Shipstar, and any possible successor volumes. I can hardly wait.

Minimizing energy cost on the interplanetary express

kw: analysis, energy, space travel, economics

It is frustrating. Space fiction is filled with 35^th Century, or 135^th Century folks flitting about space in their interstellar runabouts, going to Mars or Neptune like we might go to Omaha or Yokohama, and catching some kind of hyperspace express to cruise out to Aldebaran or some other locale a few hundred parsecs distant, for a rather modest cost.

The fact is, space travel requires a lot of energy, and energy costs something. At the moment, though, it costs more than it should because a space vehicle has to carry the fuel to make its entire journey, and we take advantage of tricks like using the atmosphere of Earth to slow the return module to parachute speed (or landing speed, for a shuttle-type vehicle, not that any currently exist).

A number of new technologies have been proposed to get a vehicle off the Earth without using any on-board fuel, such as laser propulsion. I don't propose to get into such a discussion here. Rather, given that some kind of remote assist is developed, what is the lowest cost of getting something from point A to point B?

For comparison, we might consider that it costs a few dollars ($20 or less) to ship a kilogram of any legal substance via public carriers or even the US Postal Service, say from western Pennsylvania to Massachusetts, a distance of about 800 km. If I were to personally deliver the package by driving both ways, it would cost more. My car gets 30 miles per gallon, or 48 km/gal, on the highway. That's also about 12.7 km/l. Gas (petrol) cost alone for the 1,600 km trip comes to 33.3 gallons at $4, or $133. But that's partly because the material being moved now weighs a metric ton, not just one kg. On a per kilo basis, the cost is thirteen cents. So the USPS or other carrier is only a few percent efficient, compared to my own costs, if I were carrying lots of packages in my one-ton car (and if I worked for free).

In actuality, the energy costs to the Postal Service or FedEx or whoever, are still a minor portion of total costs. But let's consider that energy-only cost a baseline: $0.133/kg to go 1,600 km, or about 8 cents per 1,000 km. Now let's consider moving a more modest 200 km, but straight up. That'll get us in the neighborhood of the ISS. USPS might charge only $5, but I doubt it. We'll consider achieving orbital velocity separately.

What's the gravitational potential difference between Earth's surface and an altitude of 200 km? Considering the Earth as a point object, which is mathematically valid from its surface outward, potential V = -GM/r. At the surface, V_s = -6.64×10^-11×5.97×10²⁴/6.37×10⁶ = -6.255×10⁷ J/kg. Add 200 to the 6,370 km radius of the earth and recalculate, and we get V_orbit = -6.065×10⁷ J/kg. Subtracting these two, we get 1.90×10⁶ J/kg. So what does that amount of energy cost?

In the US, gasoline costs $4 per gallon, and has an energy content of 3.2×10⁷ J/l or 1.2×10⁸ J/gal. The most efficient methods of using gasoline are only 30% efficient, however, so the usable energy cost is about ten cents per megajoule, or 10^-7 $/J. Liquid hydrogen can be bought for about $0.40/l, and running the figures I find it costs about 20% more than gasoline for a joule of energy obtained from hydrogen. We can use the 10¢/MJ figure for our calculations. Thus, lifting a kilogram to orbital altitude costs nineteen cents.

Keeping it there requires moving it at orbital velocity, however, which is 7,910 m/s. E_k = ½MV² = 3.13×10⁷ J/kg. This comes to $3.13/kg, more than sixteen times the cost of achieving altitude. That's an important fact about getting around in space: δv (delta vee), or change in velocity, can be a larger factor than the gravitational potential. However, at this point, let's consider that, if we truly could achieve costs as low as $3/kg to get an object into orbit, it would be revolutionary: Attaining orbit presently costs about $10,000/kg. With such a reduced cost we could think about visiting the outer planets.

The major factor going from planet to planet is the gravitational potential relative to the Sun. At Earth, this comes to -8.85×10⁸ J/kg; at Neptune, it is much smaller: -2.95×⁷ J/kg. Subtracting these yields 8.55×10⁸ J/kg, which costs $88.50/kg. Getting out of Earth's gravity well is a fraction of this (about $6/kg, similar to the cost of going to the Moon). But now there is a time factor to consider. It takes fifteen to twenty years to get to Neptune on a ballistic orbit. In other words, if some kind of energy deposition mechanism gives our one kilogram package an initial velocity of about 40 km/s, it will coast out to Neptune, and have nearly no kinetic energy left, but it might take twenty years or more.

If we increase that to Solar escape velocity, measured from Earth vicinity, or 42 km/s, it'll arrive with velocity comparable to Neptune's orbital velocity of 5.4 km/s. However, it will have required 15-16 years to travel some five billion km. To get there in one year requires a lot more initial velocity, and almost as much δv at the other end to slow down. Initial velocity needs to be of the order of 158 km/s. Kinetic energy comes to 1.25×10¹⁰, which costs $1,250. So, take your choice. A decade and a half for $88.50 or a one year delivery time for $1,250, plus another thousand-dollar slowdown fee.

These costs assume we are not accelerating fuel, just the kilogram we want to deliver. Perhaps there will one day be installations, set up by earlier generations (plural, to be sure!), that use something like laser boosting to push a projectile to these velocities, or to push against an incoming package to slow it back down. These costs are just the incremental energy costs for moving a package about. I am ignoring amortization of sunk costs (you know, the odd quadrillion or quintillion dollars to get the laser boosters into Earth orbit—or onto the Moon—, Neptune orbit, and sundry places between).

If getting to Earth orbit drops to some $3/kg, then there is some hope for a 100 kg guy like me to afford an orbital vacation. I'd gladly pay $300 each way for tickets to visit a space station, particularly if a more comfortable one than the ISS is assembled. Of course, I suspect the daily room cost will be more than at your average hotel! Going to Neptune would be more costly. Since the express trip takes a year each way (I don't have thirty years for the slower round trip!), I need some support systems, including plenty of water, air and food. Call it a couple tons. At $1,250/kg to start, $1,200 to stop, and then the same amounts for the return trip, the energy costs alone will come to nearly ten million dollars.

I don't have even one million dollars, nor much prospect of obtaining it. Vacationing in the outer solar system will probably always remain available only to the rich. What about going farther out? Stellar travel has huge time requirements, and to make it practical, the energy has to be balanced against that time.

For a number of reasons, various researchers have settled on a tradeoff velocity of 0.13c, or 39,000 km/s. That'll get you to Proxima Centauri in 33 years and Barnard's Star in 46 years. What is the energy cost? You really need laser boosting, at least at the near end, to make it practical. The relativistic kinetic energy is 7.69×10¹⁴ J/kg, at a cost of $76.9 million/kg. How many kg will a vehicle weigh, that can keep a few people alive for decades? 10,000 tons? Assuming that would do it, the energy cost is now $769 billion, or about what each of the "stimulus" packages of 2008 and 2009 cost the US government.

That is the bottom line. Sending people to a star is going to cost trillions. It may be that bombing around the inner solar system will become affordable for many of us, but even visiting the outer solar system will never be within reach to folks like me. Just getting a useful-sized spacecraft up to 0.13c is a project for a nation or a consortium of nations. Getting a kg or two in the form of a Von Neumann self-replicating robot up to such a speed is no cheap undertaking, and sending along fuel enough to allow it to slow down is another huge cost, but much less than the cost of sending people.

This doesn't mean I don't think it will be done. I expect it to take a lot more time, ingenuity, and fortitude. We especially need the planetary will to invest in technologies that enable getting off Earth, into orbit, and off to the planets, at the very least, at greatly reduced incremental cost. In today's dollars, we spent a pretty good chunk of a trillion dollars going to the Moon a few times. With any luck at all, we ought to be able to return to the Moon for one percent of that cost. The Moon is a good base for big lasers to accelerate packages once they are outside the atmosphere; an Earth-based laser facility ought to be able to get them that far. That is step one, and further steps are up to future generations of dreamers.

Space travel - behind the curtain

kw: book reviews, nonfiction, space travel, astronauts

I want to comment first on the closing words of Packing for Mars: The Curious Science of Life in the Void by Mary Roach.

"Yes, the money could be better spent on Earth. But would it? Since when has money saved by government redlining been spent on education or cancer research? It is always squandered. Let's squander some on Mars. Let's go out and play."

Squandered? True, but whether the machines and men go to Mars or other machines and men go to Afghanistan or Libya, the dollars are spent right here! People complained in 1969 about the "millions of dollars left on the Moon" by the astronauts when they returned to Earth. A $1,200 Hasselblad camera was one item left behind: "What a waste!" It would have cost much more than $1,200 to lift from the Moon back to Earth, but more than that, every single dollar spent for that camera, its marketing and procurement, and for everything else including the fuel and equipment that took the astronauts to the moon and back, was spent on Earth, primarily in the good old U S of A. We spent a trillion dollars on wars in the past ten years. Where is the money? Right here! It was spent right here and circulated in the US national economy. OK, EoR (End of Rant).

Packing for Mars is a great read that delves into all kinds of aspects of getting people into space and keeping them from dying there, and getting them back. Astronauts need to be rather different from most of us, for example. They have to be preternaturally smart, yet capable of enduring huge doses of boredom. Great self-starters, but tolerant of micromanagement because every tiny sub-task of every bit of work is scripted beforehand. They get autonomy only when things go wrong. Yet this doesn't give them much motivation to "help" things go wrong, because there are so many ways to go wrong in a fatal way, and so few ways to survive errors.

Life without gravity seems idyllic; we all dream of flying about, weightless. In a microgravity environment, though, just trying to take a drink can kill you. Those videos of astronauts that made a little ball of water, then ingested it? They had to practice a lot, with someone watching and ready to help them get the water out of their nose before they suffocated. Astronauts-in-training get nausea-control training, and still a third to half of them vomit the moment they first see someone floating upside down, or find themselves visually upside down or sideways and an odd food smell wafts by. And floating vomitus is even more dangerous than floating water. It burns while you're wiping it off. Not for nothing is the C-9 plane used for zero-g training called the Vomit Comet.

Ms Roach got a ride in the VC/C-9, and fortunately, loved it, except for the 2-G intervals between 20-second 0-G sections of the ride. When your gravity meter is going 0-2-0-2-0-2-0-2, you start to wonder just why you signed up for this ride. You have to start out absolutely adoring roller coaster rides; there is no guarantee that you'll still like them afterward. But the VC gets a lot of use because every piece of equipment has to be tested to be sure something weird doesn't happen when the G-meter reads zero.

So if water can kill you, how ya gonna bathe? Usually, they don't. An aspect of retrieving a space capsule and helping the astronauts out of it that didn't make it into the press was the incredible smell. There is a way to sponge bathe in the ISS, as there was in MIR, but nobody likes it much. But a hot shower, with water squirting everywhere? A formula for a capsule full of drowned crew.

And so it goes. Zero G erodes your bones, and nothing they have tried has been able to alleviate it much. And if sex is even possible without gravity to help a couple stay in contact, NASA isn't telling, and neither are the other space-faring nations and agencies. "Everybody" is certain it's been tried. No tales have been told.

So, we're faced with getting several humans of some average size to Mars and back, in a mission that'll take about 2.5 years. Call it a bit less than a thousand days. Food: 1.5-2 pounds daily (0.7-0.9 kg), or up to nearly a ton per person. Water: twice that amount, unless it can be efficiently recycled. Oxygen: midway between, say another ton or ton-and-a-half per person, again depending on whether it can be recycled by less massive machinery and chemicals. Then you have to absorb carbon dioxide, and the chemicals and machinery to do so come to more tons.

An aspect not covered, nay, barely mentioned, is radiation exposure. I found this article in New Scientist, which points out that a Mars mission will expose a person to more than two sieverts, assuming no extra solar flares pop off during the mission. A sievert is about a thousand CT scans. Worry #1: retired astronauts getting cancer, lots of it. It is probably best to use the oldest astronauts who are fit enough. Worry #2: non-proton cosmic rays do lots more damage than the proton and electron kind, and are prevalent enough that an astronaut's brain could lose an IQ point per month. Send up a genius, get back someone quite ordinary. Don't bother sending up an ordinary bloke; you'll get back someone who has forgotten how to read.

If this last item can be overcome, such as by having the crew encased in fifty tons of food and water on the way up, and in fifty tons of excrement and "used water" by the time they are back, then the trip is worth it. Forget the dollars. The human instrument is still the one that causes all the trouble. I vote for designing a rocket motor that goes ten times as fast! Get 'em there in thirty days, not 300, and get 'em back equally quickly. While they are there, have 'em dig in so they can at least sleep underground. Better yet, send a robotic digging facility first, so they arrive to a ready-made "subway tunnel" to live in. Now that's a mission worth fighting for!

As different an alien as he could imagine

kw: book reviews, science fiction, space travel, aliens, first contact

Peter Watts is a very accommodating writer. Following an increasingly popular practice, he has appended to his novel Blindsight a section explaining and discussing some of his ideas. Blindsight is the first book by Watts that I've read, so I don't know what he did with his earlier Rifter series (four books). In this book, he plunks us down in a society that is taking genetic and cyborganic tinkering pretty far, to the point of restoring recently lost species such as the Vampire, a Human subspecies that, being a predator on the next-most-efficient predator (us), has mental skills needed to lead increasingly complex projects, such as the mission to an object in the Oort cloud that seems to harbor an alien intelligence.

The narrator is a Synthesist, Siri Keaton. In this case, that means he's someone who had half his brain removed to eliminate debilitating epileptic seizures (complete hemispherectomy is now rare; functional hemispherectomy, which disables one hemisphere but leaves most of it in place, is performed on a few hundred people yearly). While they were at it, the installed some equipment in its place. Now, he is able to read body language well enough to just about read your mind. He is one of a team of four heavily altered and enhanced people sent to study the object they call Ben, and contact any aliens they might find. Their team leader is a Vampire.

The novel's title comes from the ability of the aliens, once encountered, to hide in plain sight. In the presence of one person, they can take advantage of the saccades, the tiny movements our eyes make constantly, to trick the brain into ignoring them. These aliens are really something. Watts has posited an alien physiology for which magnetic fields (really strong ones) and ionizing radiation interact with super-resistant proteins and superconducting polymers to produce creatures that read the electronic signals in a human brain at a distance, and the myoelectric signals from muscles, to read the people much better than Siri could hope to. All this is discovered over much time, and for much of the book, things keep going on in one mysterious way after another.

The tensions of studying the alien Scramblers, and an intelligence—artificial or otherwise, we don't find out—that controls their city-size orbiting habitat, pale by comparison to the tensions between the four very different human/cyborg crew, and the most-different member, the Vampire. In the end, we find that selective attention, which enables conscious beings to function in a very stimulus-rich world, is a fatal detriment to us in the presence of creatures that seem not to be conscious as we know it, but can process all stimuli in real time; their attention is not selective, so they learn really, really fast.

The concept of a Chinese Room is used to great effect to explain the difference. This thought experiment by John Searle is used to question the meaning and usefulness of the Turing Test. One the one hand, Turing asked, if you communicate with a computer by teletype, and cannot determine whether it truly is a computer, is it intelligent? On the other, Searle proposed a person in a room who receives written or printed messages that he cannot understand, but that he can recognize and find in a large (very large, I'd think!) rule book. He doesn't even know they are Chinese ideographs. He just looks up in the rule book how to respond, and writes the response on a fresh sheet of paper and passes it outside the room to an observer. Is the Chinese Room intelligent?

Some think consciousness is an illusion. Descartes offered the best reply (I think, thus I am). I know I am conscious, and you know that you are conscious. That poor soul over there doesn't think either one of us is conscious, but perhaps he (she?) just suffers from impaired self-consciousness...