Fourmilog: None Dare Call It Reason

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Thursday, July 30, 2015

Reading List: Superman: Red Son

Millar, Mark, Dave Johnson, and Kilian Plunkett. Superman: Red Son. New York: DC Comics, [2003] 2014. ISBN 978-1-4012-4711-9.

On June 30th, 1908, a small asteroid or comet struck the Earth's atmosphere and exploded above the Tunguska river in Siberia. The impact is estimated to have released energy equivalent to 10 to 15 megatons of TNT; it is the largest impact event in recorded history. Had the impactor been so aligned as to hit the Earth three hours later, it would have exploded above the city of Saint Petersburg, completely destroying it.

In a fictional universe, an alien spaceship crashes in rural Kansas in the United States, carrying an orphan from the stars who, as he matures, discovers he has powers beyond those of inhabitants of Earth, and vows to use these gifts to promote and defend truth, justice, and the American way. Now, like Tunguska, imagine the spaceship arrived a few hours earlier. Then, the baby Kal-El would have landed in Stalin's Soviet Union and, presumably, imbibed its values and culture just as Superman did in the standard canon. That is the premise of this delightful alternative universe take on the Superman legend, produced by DC Comics and written and illustrated up the standards one expects from the publisher. The Soviet Superman becomes an extraterrestrial embodiment of the Stakhanovite ideal, and it is only natural that when the beloved Stalin dies, he is succeeded by another Man of Steel.

The Soviet system may have given lip service to the masses, but beneath it was the Russian tradition of authority, and what better authority than a genuine superman? A golden age ensues, with Soviet/Superman communism triumphant around the globe, apart from recalcitrant holdouts Chile and the United States. But all are not happy with this situation, which some see as subjugation to an alien ruler. In the Soviet Union Batman becomes the symbol and leader of an underground resistance. United States president and supergenius Lex Luthor hatches scheme after scheme to bring down his arch-enemy, enlisting other DC superheroes as well as his own creations in the effort. Finally, Superman is forced to make a profound choice about human destiny and his own role in it. The conclusion to the story is breathtaking.

This is a well-crafted and self-consistent alternative to the fictional universe with which we're well acquainted. It is not a parody like Tales of the Bizarro World (November 2007), and in no way played for laughs. The Kindle edition is superbly produced, but you may have to zoom into some of the pages containing the introductory material to be able to read the small type. Sketches of characters under development by the artists are included in an appendix.

Posted at 23:32

Monday, July 27, 2015

Reading List: GPS Declassified

Easton, Richard D. and Eric F. Frazier. GPS Declassified. Lincoln, NE: Potomac Books, 2013. ISBN 978-1-61234-408-9.

At the dawn of the space age, as the United States planned to launch its Vanguard satellites during the International Geophysical Year (1957–1958), the need to track the orbit of the satellites became apparent. Optical and radar tracking were considered (and eventually used for various applications), but for the first very small satellites would have been difficult. The Naval Research Laboratory proposed a system, Minitrack, which would use the radio beacon of the satellite, received by multiple ground stations on the Earth, which by interferometry would determine the position and velocity of a satellite with great precision. For the scheme to work, a “fence” of receiving stations would have to be laid out which the satellite would regularly cross in its orbit, the positions of each of the receiving stations would have to be known very accurately, and clocks at all of the receiving stations would have to be precisely synchronised with a master clock at the control station which calculated the satellite's orbit.

The technical challenges were overcome, and Minitrack stations were placed into operation at locations within the United States and as far flung as Cuba, Panama, Ecuador, Peru, Chile, Australia, and in the Caribbean. Although designed to track the U.S. Vanguard satellites, after the unexpected launch of Sputnik, receivers were hastily modified to receive the frequency on which it transmitted its beeps, and the system successfully proved itself tracking the first Earth satellite. Minitrack was used to track subsequent U.S. and Soviet satellites until it was supplanted in 1962 by the more capable Spacecraft Tracking and Data Acquisition Network.

An important part of creative engineering is discovering that once you've solved one problem, you may now have the tools at hand to address other tasks, sometimes more important that the one which motivated the development of the enabling technologies in the first place. It didn't take long for a group of engineers at the Naval Research Laboratory (NRL) to realise that if you could determine the precise position and velocity of a satellite in orbit by receiving signals simultaneously at multiple stations on the ground with precisely-synchronised clocks, you could invert the problem and, by receiving signals from multiple satellites in known orbits, each with an accurate and synchronised clock on board, it would be possible to determine the position, altitude, and velocity of the receiver on or above the Earth (and, in addition, provide a precise time signal). With a sufficiently extensive constellation of satellites, precision navigation and time signals could be extended to the entire planet. This was the genesis of the Global Positioning System (GPS) which has become a ubiquitous part of our lives today.

At the start, this concept was “exploratory engineering”: envisioning what could be done (violating no known law of physics) if and when technology advanced to a stage which permitted it. The timing accuracy required for precision navigation could be achieved by atomic clocks (quartz frequency standards were insufficiently stable and subject to drift due to temperature, pressure, and age of the crystal), but in the 1950s and early '60s, atomic clocks were large, heavy, and delicate laboratory apparatus which nobody imagined could be put on top of a rocket and shot into Earth orbit. Just launching single satellites into low Earth orbit was a challenge, with dramatic launch failures and in-orbit malfunctions all too common. The thought of operating a constellation of dozens of satellites in precisely-specified high orbits seemed like science fiction. And even if the satellites with atomic clocks could somehow be launched, the radio technology to receive the faint signals from space and computation required to extract position and velocity information from the signal was something which might take a room full of equipment: hardly practical for a large aircraft or even a small ship.

But the funny thing about an exponentially growing technology is if something seems completely infeasible today, just wait a few years. Often, it will move from impossible to difficult to practical for limited applications to something in everybody's pocket. So it has been with GPS, as this excellent book recounts. In 1964, engineers at NRL (including author Easton's father, Roger L. Easton) proposed a system called Timation, in which miniaturised and ruggedised atomic clocks on board satellites would provide time signals which could be used for navigation on land, sea, and air. After ground based tests and using aircraft to simulate the satellite signal, in 1967 the Timation I satellite was launched to demonstrate the operation of an atomic clock in orbit and use of its signals on the ground. With a single satellite in a relatively low orbit, the satellite would only be visible from a given location for thirteen minutes at a time, but this was sufficient to demonstrate the feasibility of the concept.

As the Timation concept was evolving (a second satellite test was launched in 1969, demonstrating improved accuracy), it was not without competition. The U.S. had long been operating the LORAN system for coarse-grained marine and aircraft navigation, and had beacons marking airways across the country. Starting in 1964, the U.S. Navy's Transit satellite navigation system (which used a Doppler measurement system and did not require a precise clock on the satellites) provided periodic position fixes for Navy submarines and surface ships, but was inadequate for aircraft navigation. In the search for a more capable system, Timation competed with an Air Force proposal for regional satellite constellations including geosynchronous and inclined elliptical orbit satellites.

The development of GPS began in earnest in 1973, with the Air Force designated as the lead service. This project launch occurred in the midst of an inter-service rivalry over navigation systems which did not abate with the official launch of the project. Indeed, even in retrospect, participants in the program dispute how much the eventually deployed system owes to its various precursors. Throughout the 1970s the design of the system was refined and pathfinder technology development missions launched, with the first launch of an experimental satellite in February 1978. One satellite is a stunt, but by 1985 a constellation of 10 experimental satellites were in orbit, allowing the performance of the system to be evaluated, constellation management tools to be developed and tested, and receiver hardware to be checked out. Starting in 1989 operational satellites began to be launched, but it was not until 1993 that worldwide, round-the clock coverage was available, and the high-precision military signal was not declared operational until 1995.

Even though GPS coverage was spotty and not continuous, GPS played an important part in the first Gulf War of 1990–1991. Because the military had lagged in procuring GPS receivers for the troops, large numbers of commercial GPS units were purchased and pressed into service for navigating in the desert. A few GPS-guided weapons were used in the conflict, but their importance was insignificant compared to other precision-guided munitions.

Prior to May 2000 the civilian GPS signal was deliberately degraded in accuracy (can't allow the taxpayers who paid for it to have the same quality of navigation as costumed minions of the state!) This so-called “selective availability” was finally discontinued, making GPS practical for vehicle and non-precision air navigation. GPS units began to appear on the consumer market, and like other electronic gadgets got smaller, lighter, less expensive, and more capable with every passing year. Adoption of GPS for tracking of fleets of trucks, marine navigation, and aircraft use became widespread.

Now that GPS is commonplace and hundreds of millions of people are walking around with GPS receivers in their smartphones, there is a great deal of misunderstanding about precisely what GPS entails. GPS—the Global Positioning System—is precisely that: a system which allows anybody with a compatible receiver and a view of the sky which allows them to see four or more satellites to determine their state vector (latitude, longitude, and altitude, plus velocity in each of those three directions) in a specified co-ordinate system (where much additional complexity lurks, which I'll gloss over here), along with the precise time of the measurement. That's all it does. GPS is entirely passive: the GPS receiver sends nothing back to the satellite, and hence the satellite system is able to accommodate an unlimited number of GPS receivers simultaneously. There is no such thing as a “GPS tracker” which can monitor the position of something via satellite. Trackers use GPS to determine their position, but then report the position by other means (for example, the mobile phone network). When people speak of “their GPS” giving directions, GPS is only telling them where they are and where they're going at each instant. All the rest: map display, turn-by-turn directions, etc. is a “big data” application running either locally on the GPS receiver or using resources in the “cloud”: GPS itself plays no part in this (and shouldn't be blamed when “your GPS” sends you the wrong way down a one-way street).

So successful has GPS been, and so deeply has it become embedded in our technological society and economy, that there are legitimate worries about such a system being under the sole control of the U.S. Air Force which could, if ordered, shut down the civilian GPS signals worldwide or regionally (because of the altitude of the satellites, fine-grained denial of GPS availability would not be possible). Also, the U.S. does not have the best record of maintaining vital infrastructure and has often depended upon weather satellites well beyond their expected lifetimes due to budget crunches. Consequently, other players have entered the global positioning market, with the Soviet/Russian GLONASS, European Galileo, and Chinese BeiDou systems operational or under construction. Other countries, including Japan, India, and Iran, are said to be developing their own regional navigation systems. So far, cooperation among these operators has been relatively smooth, reducing the likelihood of interference and making it possible for future receivers to use multiple constellations for better coverage and precision.

This is a comprehensive history of navigation systems and GPS from inception to the present day, with a look into the future. Extensive source citations are given (almost 40% of the book is end notes), and in the Kindle edition the notes, Web documents cited within them, and the index are all properly linked. There are abundant technical details about the design and operation of the system, but the book is entirely accessible to the intelligent layman. In the lifetimes of all but the youngest people on Earth, GPS has transformed our world into a place where nobody need ever be lost. We are just beginning to see the ramifications of this technology on the economy and how we live our day-to-day lives (for example, the emerging technology of self-driving cars would be impossible without GPS). This book is an essential history of how this technology came to be, how it works, and where it may be going in the future.

Posted at 23:53

Friday, July 17, 2015

Reading List: Code of Conduct

Thor, Brad. Code of Conduct. New York: Atria Books, 2015. ISBN 978-1-4767-1715-9.

This is the fifteenth in the author's Scot Harvath series, which began with The Lions of Lucerne (October 2010). In this novel, the author “goes big”, with a thriller whose global implications are soundly grounded in genuine documents of the anti-human “progressive” fringe and endorsed, at least implicitly, by programmes of the United Nations.

A short video, recorded at a humanitarian medical clinic in the Congo, shows a massacre of patients and staff which seems to make no sense at all. The operator of the clinic retains the Carlton Group to investigate the attack on its facility, and senior operative Scot Harvath is dispatched to lead a team to find out what happened and why. Murphy's Law applies at all times and places, but Murphy seems to pull extra shifts in the Congo, and Harvath's team must overcome rebels, the elements, and a cast-iron humanitarian to complete its mission.

As pieces of evidence are assembled, it becomes clear that the Congo massacre was a side-show of a plot with global implications, orchestrated by a cabal of international élites and supported by bien pensants in un-elected senior administrative positions in governments. Having bought into the anti-human agenda, they are willing to implement a plan to “restore equilibrium” and “ensure sustainability” whatever the human toll.

This is less a shoot-'em-up action thriller (although there is some of that, to be sure), than the unmasking of a hideous plot and take-down of it once it is already unleashed. It is a thoroughly satisfying yarn, and many readers may not be aware of the extent to which the goals advocated by the villains have been openly stated by senior officials of both the U.S. government and international bodies.

This is not one of those thrillers where once the dust settles things are left pretty much as they were before. The world at the end of this book will have been profoundly changed from that at the start. It will be interesting to see how the author handles this in the next volume in the series.

For a high-profile summer thriller by a blockbuster author from a major publishing house (Atria is an imprint of Simon & Schuster), which debuted at number 3 on the New York Times Best Sellers list, there are a surprising number of copy editing and factual errors, even including the platinum standard, an idiot “It's” on p. 116. Something odd appears to have happened in formatting the Kindle edition (although I haven't confirmed that it doesn't also affect the print edition): a hyphen occasionally appears at the end of lines, separated by a space from the preceding word, where no hyphenation is appropriate, for example: “State - Department”.

Posted at 23:54

Wednesday, July 8, 2015

Reading List: StarTram

Powell, James, George Maise, and Charles Pellegrino. StarTram. Seattle: CreateSpace, 2013. ISBN 978-1-4935-7757-6.

Magnetic levitation allows suspending a vehicle above a guideway by the force of magnetic repulsion. A train using magnetic levitation avoids the vibration, noise, and rolling resistance of wheels on rails, and its speed is limited only by air resistance and the amount of acceleration passengers consider tolerable. The Shanghai Maglev Train, in service since 2004, is the fastest train in commercial passenger service today, and travels at 431 kilometres per hour in regular operation. Suppose you were able to somehow get rid of the air resistance and carry only cargo, which can tolerate high acceleration. It would appear that if the technical challenges could be met, the sky would be the limit. In this book the authors argue that the sky is just the start.

They propose a space launch system called StarTram, to be developed in two technological generations. The Generation 1 (Gen-1) system is for cargo only, and uses an evacuated launch tube 110 km long in an underground tunnel. This sounds ambitious, but the three tunnels under the English Channel total 150 km, and are much larger than that required for StarTram. The launcher will be located at a site which allows the tube to run up a mountain, emerging in the thinner air at an altitude between 3 and 7 kilometres. There will be an extreme sonic boom as the launch vehicle emerges from the launch tube at a velocity of around 8 kilometres per second and flies upward through the atmosphere, so the launcher will have to be located in a region where the trajectory downrange for a sufficient distance is unpopulated. Several candidate sites on different continents are proposed.

The Gen-1 cargo craft is levitated by means of high (liquid nitrogen) temperature superconducting magnets which are chilled immediately before launch. They need only remain superconducting for the launch itself, around 30 seconds, so a small on-board supply of liquid nitrogen will suffice for refrigeration. These superconducting magnets repel loops of aluminium in the evacuated guideway tube; no refrigeration of these loops is required. One of the greatest technical challenges of the system is delivering the electric power needed to accelerate the cargo craft. In the 30 seconds or so of acceleration at 30 gravities, the average power requirement is 47 gigawatts, with a peak of 94 gigawatts as orbital velocity is approached. A typical commercial grid power plant produces around 1 gigawatt of power, so it is utterly impractical to generate this power on site. But the total energy required for a launch is only about 20 minutes' output from a 1 gigawatt power station. The StarTram design, therefore, incorporates sixty superconducting energy storage loops, which accumulate the energy for a launch from the grid over time, then discharge to propel the vehicle as it is accelerated. The authors note that the energy storage loops are comparable in magnitude to the superconducting magnets of the Large Hadron Collider, and require neither the extreme precision nor the liquid helium refrigeration those magnets do.

You wouldn't want to ride a Gen-1 cargo launcher. It accelerates at around 30 gravities as it goes down the launch tube, then when it emerges into the atmosphere, decelerates at a rate between 6 and 12g until it flies into the thinner atmosphere. Upon reaching orbital altitude, a small rocket kick motor circularises the orbit. After delivering the payload into orbit (if launching to a higher orbit or one with a different inclination, the payload would contain its own rocket or electric propulsion to reach the desired orbit), the cargo vehicle would make a deorbit burn with the same small rocket it used to circularise its orbit, extend wings, and glide back for re-use.

You may be wondering how a tunnel, evacuated to a sufficiently low pressure to allow a craft to accelerate to orbital velocity without being incinerated, works exactly when one end has to be open to allow the vehicle to emerge into the atmosphere. That bothers me too, a lot. The authors propose that the exit end of the tube will have a door which pops open just before the vehicle is about to emerge. The air at the exit will be ionised by seeding with a conductive material, such as cæsium vapour, then pumped outward by a strong DC current, operating as the inverse of a magnetohydrodynamic generator. Steam generators at the exit of the launch tube force away the ambient air, reducing air pressure as is done for testing upper stage rocket motors. This is something I'd definitely want to see prototyped in both small and full scale before proceeding. Once the cargo craft has emerged, the lid slams shut.

Launching 10 cargo ships a day, the Gen-1 system could deliver 128,000 tons of payload into orbit a year, around 500 times that of all existing rocket launch systems combined. The construction cost of the Gen-1 system is estimated at around US$20 billion, and with all major components reusable, its operating cost is electricity, maintenance, staff, and the small amount of rocket fuel expended in circularising the orbit of craft and deorbiting them. The estimated all-up cost of launching a kilogram of payload is US$43, which is about one hundredth of current launch costs. The launch capacity is adequate to build a robust industrial presence in space, including solar power satellites which beam power to the Earth.

Twenty billion dollars isn't small change, but it's comparable to the development budget for NASA's grotesque Space Launch System, which will fly only every few years and cost on the order of US$2 billion per launch, with everything being thrown away on each mission.

As noted, the Gen-1 system is unsuited to launching people. You could launch people in it, but they wouldn't still be people when they arrived on orbit, due to the accelerations experienced. To launch people, a far more ambitious Gen-2 system is proposed. To reduce launch acceleration to acceptable levels, the launch tunnel would have to be around 1500 km long. To put this into perspective, that's about the distance from Los Angeles to Seattle. To avoid the bruising deceleration (and concomitant loss of velocity) when the vehicle emerges from the launch tube, the end of the launch tube will be magnetically levitated by superconducting magnets (restrained by tethers) so that the end is at an altitude of 20 km. Clearly there'll have to be a no-fly zone around the levitated launch tube, and you really don't want the levitation system to fail. The authors estimate the capital cost of the Gen-2 system at US$67 billion, which seems wildly optimistic to me. Imagine how many forms you'll have to fill out to dig a 1500 km tunnel anywhere in the world, not to speak of actually building one, and then you have to develop that massive magnetically levitated launch tube, which has never been demonstrated.

Essentially everything I have described so far appears in chapter 2 of this book, which makes up less than 10% of its 204 pages. You can read a complete description of the StarTram system for free in this technical paper from 2010. The rest of the book is, well, a mess. With its topic, magnetic levitation space launch, dispensed with by the second chapter, it then veers into describing all of the aspects of our bright future in space such a system will open, including solar power satellites, protecting the Earth from asteroid and comet impacts, space tourism, colonising Mars, exploring the atmosphere of Jupiter, searching for life on the moons of the outer planets, harvesting helium-3 from the atmospheres of the outer planets for fusion power, building a telescope at the gravitational lensing point of the Sun, and interstellar missions. Dark scenarios are presented in which the country which builds StarTram first uses it to establish a global hegemony enforced by all-seeing surveillance from space and “Rods from God”, orbited in their multitudes by StarTram, and a world where the emerging empire is denied access to space by a deliberate effort by one or more second movers to orbit debris to make any use of low orbits impossible, imprisoning humanity on this planet. (But for how long? Small particles in low orbit decay pretty quickly.) Even wilder speculations about intelligent life in the universe and an appropriate strategy for humans in the face of a potentially hostile universe close the book.

All of this is fine, but none of it is new. The only new concept here is StarTram itself, and if the book concentrated just on that, it would be a mere 16 pages. The rest is essentially filler, rehashing other aspects of the human future in space, which would be enabled by any means of providing cheap access to low Earth orbit. The essential question is whether the key enabling technologies of StarTram will work, and that is a matter of engineering which can be determined by component tests before committing to the full-scale project. Were I the NASA administrator and had the power to do so (which, in reality, the NASA administrator does not, being subordinate to the will of appropriators in Congress who mandate NASA priorities in the interest of civil service and contractor jobs in their districts and states), I would cancel the Space Launch System in an instant and use a small part of the savings to fund risk reduction and component tests of the difficult parts of a Gen-1 StarTram launcher.

Posted at 01:10

Wednesday, July 1, 2015

Leap Second

Take that, alarm clock!

Posted at 02:22