Friday, July 30, 2010

Sesquicentennial, Part III: The Past is Prologue


How did it come to this? How did it get so bad that the signs became so big that even a blind man could see them? The Election of 1860 had shaped up into a four-way scrum that was probably going to tear the country apart no matter who won. Only one and two generations before, their fathers and grandfathers had fought side-by-side against the British; now, they were practically baying for one another's blood. How did it get so bad, so fast?

There was a fundamental problem baked into the Constitution at its inception in 1787. Everyone knew what it was, but no one wanted to tackle the problem straight away. The coming storm would be the price of procrastination. But to understand the problem, and how it shaped the development of the United States during the first half of the 19th Century, we have to dig back a lot farther than that.

The first thing to understand is that passage from the Old World to the New wasn't exactly free. The ships involved in setting up the first colonies back in the 1600s represented the pinnacle of the day's technology. They might well have been dropped off in the wilderness with nothing but the clothes on their backs, but they rode there in the Space Shuttles of their day.

Not all of them could afford the fare for the trip. Actually, only about one in five could. The rest partook of an arrangement called indentured servitude.

Being an indentured servant wasn't any fun, but there was an end to it. Once you fulfilled your contract, usually three to seven years' labor, you were free to go about whatever business you could find. There was always new land to be broken up for farming.

Initially, this was how all of the North American colonies were populated. But, in parallel with this, another system of unfree labor was taking shape. In the labor-intensive tobacco plantations of Virginia, and also in Spanish Florida, farmers began to import Africans as slaves. Soon, these plantations stopped using indentured servants entirely, for several reasons. For one, no one in his right mind would sign an indenture contract to go hustle tobacco in Virginia, or (God help you) the Carolinas, when he could go to New England instead. There were few takers at any price, so the planters eventually stopped asking. For another, it takes a while to teach a new hand how the job is done, and that training is lost when the indenturee completes his contract.

So, even by the time of the Revolution, the northern and southern sections of the country had a markedly different composition. The North was a region of smaller farms, tradesmen, and craftsmen; a diverse economy based on manufacturing and trade. The South was dominated by wealthy planters who owned large plantations, and their economy lived or died by the export of their cash crop. The North was trending towards increasing egalitarianism, while the South was trending towards an entrenched aristocracy.

That was the situation as of 1787. Each side had its doubts about the other, but both needed each other in the face of the external enemy, the British. This state of affairs lasted to about 1820. Then, the knives started to come out.

It was all about the balance of power in the Senate. For the South, it was vital to maintain if not a majority, then at least a parity of power in the Senate. This would allow them enough seats in the upper house to block any Constitutional changes that would affect the institution of slavery. They were keen, very keen, on inducting new States into the Union that would permit slavery, and thereby keep parity. They were content to go one-for-one with the North on this. That is where the Missouri Compromise came from. Basically, this was the disposition of the new territories purchased for the Union by President Jefferson. The State of Missouri would be admitted as a slave-holding State. Slavery would be allowed in unincorporated territory south of parallel 36°30' north latitude, and forbidden in territories to the north.

Many observers hailed the Missouri Compromise as a triumph of negotiation. Not everyone was satisfied. Thomas Jefferson foresaw doom when he wrote to a friend that "this momentous question, like a fire bell in the night, awakened and filled me with terror." He was right, because the Missouri Compromise Line basically sealed the deal, but it would be another generation before that fact became clear.

The next crisis would involve the Mexican-American War of 1848. In 1836, Texas fought a successful revolution against Mexico, and became an independent republic. But Texas was saddled with a massive debt that was becoming impossible to pay. So, Texas decided discretion was the better part of valor, and petitioned the United States Congress for entry to the Union in 1845. Congress accepted their offer, since Texas brought a nice chunk of land along with them ... except, of course, that they didn't necessarily have clear title to the land on offer. Mexico begged to differ. Mexico probably had a valid point, but the tips of General Taylor's soldiers' bayonets were pointier still, and carried the day. Mexico lost not only the disputed land that Texas had claimed, but everything between that and the Pacific as well.

On the one hand, people across the United States rubbed their hands together: "Oh boy! More land!" But on the other hand ... "Oh crap! NOW what do we do? How do we divide this mess up?" It took a couple of years to sort everything out. The basic shape of the deal was that the Missouri Compromise line would be extended to the Pacific. South of 36°30', slavery OK; north, forbidden. But a funny thing happened on the way to the bargaining table...

In 1849, a curious mineral find in California changed everything. Yes, sports fans, there's gold in them thar hills! Men flocked to California to get in on this action. Enough, in fact, to allow a shrewd group of Californians to petition the Union for Statehood. In an ordinary year they'd have been ignored. But they had gold, and plenty of it, and then just like now, cash talked.

And California entered the Union as a state forbidding slavery.

That sound you just heard was an echo of the wail of frustration from the South when they looked at this map:

Just like that, they'd been outflanked.

This was when the desperation began to flourish. This was when the really crazy things began to percolate. Like the Knights of the Golden Circle, for example; or the plans to invade Cuba and Central America to gain new slave-friendly territory to incorporate as States. This was the older, now-disused meaning of the word filibuster, as applied by one William Walker. Nothing came of any of this ... but any educated Southerner who could read a map knew they were doomed.

And that was ... a problem.

By 1860, there were four million slaves in the United States, collectively worth $3.5 billion. Yes, that's "billion" with a B, and yes, that's 1860. That's equivalent to $75 billion today: roughly the same amount of money (in 2010 dollars) that we spent to put a man on the Moon. Slaves were the single largest capital asset in the entire United States economy. Ahead of the railroads. Ahead of the factories.

Chew on that number for a second, and you'll know why they weren't giving up without a fight. The cause they fought for was evil, but by and large these were not irrational men.

Between 1850 and 1860, positions did nothing but harden. The North knew it held the trump cards, and knew time was on its side. Abolitionists became progressively more vocal and more strident. The South knew that, eventually, they'd be forced to forfeit a gigantic financial asset. Things almost came to a head in 1856, the first year a Republican candidate ran for President. James Buchanan, a Democrat, was elected on the premise that he'd be able to hold the Union together.

It would not come to light until a year later, but Buchanan's Secretary of War, John Floyd, was issuing some ... innovative orders to the Army. He had ordered 115,000 muskets and rifles shipped to Southern armories, and heavy ordinance shipped to depots at Galveston Harbor in Texas and Ship Island in Mississippi. He also saw to it that units posted in the South had, shall we say, sympathetic commanders.

The powder keg and fuse had been set. All it wanted was a match. The Presidential election was only three months away.

Friday, July 23, 2010

L'Roi C'Est Mort, Vive L'Roi

"No king rules forever, my son." -- King Terenas Menethil II

For seven consecutive years, Lance Armstrong was able to avoid major trouble. He had assembled a team around him that had some of the world's best cyclists, and he had the experience to avoid problems before they cropped up. But still, seven Tours without a major crash or major mechanical problem is an astonishing run of luck. Even allowing for the fact that much of the time luck results from preparation, staying that good for that long was a singular achievement.

This year, his luck appears to have run out. By the end of the first week, Armstrong's attempt to win an eighth Tour de France was essentially over, after a disastrous series of crashes. Crashes that, five years ago, he'd have danced around almost effortlessly. But five years of age have robbed him of the quickness he once had: the crashes left him bandaged, hurt, and tens of minutes out of contention. It's not a complete loss. He's stayed in, and it looks as if his Radio Shack squad might capture the overall team classification.

Still, it's clear: the crown must now pass to a new generation.

This year, it's a hard-fought race between two exceptional young men. One has won the race twice before: Alberto Contador, who holds the lead by a scant eight seconds. The gentleman on his left in the photo above is in second place going into Saturday's time trial: Andy Schleck. They are almost perfectly evenly matched. Contador has an edge in experience, and has won the last four Grand Tours he's entered. Schleck has strength, endurance, and an increasing amount of poise and confidence. If I were betting ... well, I wouldn't. I honestly have no idea who's going to be stronger tomorrow.

But I do think that Alberto Contador is the dominant cyclist of his generation. The crown is his, if he can ride hard enough to keep it. He's probably good enough to earn another two or three to follow, though that remains to be seen.

L'Roi c'est mort. Vive l'Roi!

Friday, July 16, 2010

Space Travel for Dummies, Part 7: Case Study, Part 2


Last time, we took up the plight of the wayward Galaxy 15 satellite, and started looking into how we'd go about building what amounts to a space-going garbage truck. Someone's going to have to build one eventually. We may as well see how hard it's going to be. We got a good start on that last time, by figuring out we would need a delta-V (DV) budget of 20,086 meters per second to accomplish the stated mission.

This is directly related to the amount of fuel you have to burn to get from here to there and back again. About a hundred years ago, Konstantin Tsiolkovskii became interested in the mathematics of space travel, and got to work figuring out how to compute the performance of a space-going rocket. The equation he derived was:

(DV) = (Ve) * ln ( Mi / Mf )

where (DV) is the velocity change of the rocket, (Ve) is the exhaust velocity, (Mi) is the initial vehicle mass, and (Mf) is the vehicle mass at burnout. In some texts, you'll see the ratio (Mi/Mf) written as (R). The exhaust velocity (Ve) is a function of the rocket engine you're using. Depending on who you talk to and how they're feeling that day, you'll hear this equation called either the Rocket Equation or Tsiolkovskii's Equation.

This gives us enough information to compute the ratio of the initial mass to the burnout mass of the rocket, which isn't quite enough information for us to estimate a takeoff gross weight for the rocket. The burnout mass of the rocket will consist of two different kinds of things: things that have a fixed mass, and things whose mass can "float". Things that have a fixed mass are your crew, your payload, the life support system, things like that. You know how much they weigh, and that's independent of how big or small the rocket ends up being. Things that can "float" are everything else: structure, engines, plumbing. Eventually, you have to nail hard numbers down for everything, of course; but you have to start somewhere.

Now, we can expand the mass ratio computation a little bit to reflect this:

(Mi/Mf) = ( Me + Mp + MP ) / ( Me + MP )

where (Me) is the empty or dead weight, (Mp) is the mass of propellant, and (MP) is the payload mass. Here, "payload" means anything whose mass is fixed. So, if it's a multistage rocket, the "payload" is the entire upper stage.

This leaves us with a small problem: if we know values for (MP) and (DV), we still don't know what either (Me) or (Mp) are. That is, we have one equation and two unknowns. In order to go any further, we have to make an assumption about (Me). There are a few different approaches, but the easiest is to assume that (Me) is some fraction of the total stage weight. For this example, we are going to use a fraction of 0.1. This is an exceedingly optimistic value, but will serve to illustrate the point. Substituting:

(Mi/Mf) = ( Mp + 0.9 * MP ) / ( 0.1 * Mp + 0.9 * MP )

Given (DV) and (MP), we can solve for (Mp), and then we can compute the overall vehicle mass.

For this example, the fixed-mass items are:

(1) Crew cabin: 3,000 kilograms
(2) Payload: 8,000 kilograms (one satellite up, one satellite down)

So, MP = 11,000 kilograms, at least on Earth return.

GUESS 1: We're going to try to use a single stage to do the job. I basically know this won't work, but we'll try it anyway. Using DV=20,086 and MP=11,000, we throw the numbers in and ... we get a negative number for gross weight. Well, that just tells us you can't get there from here. (It's a standard engineering sanity check -- when your equations return nonsense, you've either made an arithmetic error, or you've assumed something to be possible that really isn't.)

GUESS 2: Now, we'll try a two-stage vehicle, one to put the stack into orbit, the second to get us the rest of the way there and back. This works out to approximately DV=10,000 for each stage. For the second stage, we get an initial weight of ... another negative number. So that won't work, either.

GUESS 3: We're up to three stages now. Splitting our DV up three ways gives us about 7,000 to cover with each stage. For the third stage, we get ... hey, it's a positive integer! Third stage weighs in at 134 tons. Second stage, 1,637 tons. Which gives us a grand total of 19,971 tons gross weight at liftoff.

At this point, I would like to observe that the Saturn V rocket tipped the scales at 6.5 million pounds on the pad, or 3,250 tons. It is the largest object known to have flown under its own power. So, our garbage truck tips the scales at about six times the weight of the biggest thing that's ever flown in the entire history of forever.

Yeah, that sucker ain't never gonna get built. Even I'm not that crazy.

We're giving up on this concept at three stages. Theoretically, there's no reason we couldn't go to four or even five stages; and the gross weight would probably come down some more. But there are two problems. One, you reach a point of diminishing returns. You don't realize enough mass reduction to make the additional complexity worthwhile. Another is operationally-driven. With three stages, each stage is recoverable and reusable, at least in principle. With a fourth stage, you're just about committed to leaving at least some hardware "out there", which kind of defeats the purpose of the vehicle.

Well, that stinks. But we're not quite done, yet.

Let's think about what it is we really need to do. We need to get to and from low earth orbit. Then we need to get to and from geosynchronous orbit. There's no law that says the same vehicle has to do both.

So: we have two different vehicles. One is robotic, and runs from LEO to GEO. The other has a crew, and flies from the ground into orbit. They meet at a depot, where the shuttle drops off fuel and upward-bound satellites, and the truck refuels and takes fresh satellites up, bringing expended satellites back for disposal. Further, since the truck never needs to come back to Earth, it doesn't need a high-thrust engine, so we can use lower-thrust but higher-efficiency engines.

Let's take a first pass at RoboTruck: it carries 10,000 kg worth of fixed-mass items, and uses electric engines with an exhaust velocity of approximately 20,000 m/s. To get to GEO and back, it needs a total DV capacity of 10,000 m/s. Putting those numbers into our above equation gives us a total RoboTruck weight of right at 18 tons. Quite reasonable.

Now, our ground-to-orbit ship needs to be able to carry either a full RoboTruck, or a satellite plus some amount of fuel. Let's say, 20 tons total. It needs a DV capacity of 10,000 m/s. Putting this into our equations yields a third-stage mass of 54 tons, second-stage total mass of 115 tons, and total pad weight of 389 tons.

This, we can do. It's still fairly hefty, but not so much so that it beggars the imagination. All the bits are recoverable and reusable, so we aren't contributing to the debris problem. And it's conceivable with current technology. On the down side, it's sufficiently expensive that its benefit doesn't justify the cost of actually bending metal to build it.

Which brings up one last question: what's the price point where something like this would be worth building? My guess is that engines would have to be much, much more efficient and powerful. Say, if you were able to build a high-thrust engine that was almost as efficient as an electric rocket ... able to generate exhaust velocities of about 10,000 m/s and still be powerful enough to lift itself. Such a vehicle with three stages would weigh in at only a hundred tons or so, and a single-stage model would "only" tip the scales at 300 tons or thereabouts.

Such engines become a real possibility, once we unlock the secret of controlled nuclear fusion. But that's a story for another day ... we hope.

Friday, July 09, 2010

A Fifth Star?

I forget precisely where I saw this blurb, but I saw a note this week suggesting the promotion of General David Petraeus to the rank of General of the Army, a rank that hasn't been held by an American officer since the death of Omar Bradley in 1981.

I don't think this will happen, nor do I think it should. Let's review the history of this rank, and see why it was ever awarded in the first place.

In the late 19th and early 20th Century, the nations of Europe began using universal conscription to fill their armies. This was by itself nothing new. What was new was the fact that the men, once discharged, remained in reserve formations that would meet once a year or so to update their rolls. The theory was that, if a war broke out, a nation with a large trained reserve could in very short order have a very large army indeed.

This was one of the few theories of World War I that was borne out in reality. The European armies were huge, on a scale heretofore unseen in history. They were, in fact, so huge as to be unmanageable by an ordinary general officer. It's the basic span of control problem: one man can only effectively manage three to five direct reports. If you add more, he can pretend to manage them, but won't actually do very well. If you have ten million men under arms, that pretty much spells out for you how many echelons of command you need. You cannot run a war with a committee of ten four-star generals, you have to put one in charge. Therefore, they all found it necessary to appoint Field Marshals, officers superior in grade to every other general officer, who could then assemble a command staff to run things. The system seemed to work tolerably.

When the United States entered the war in 1917, Congress was presented with a bit of a problem. The man they had tapped to lead the American Expeditionary Force, John J. Pershing, would be junior by definition to his alleged peers in England and France. But America did not have a rank higher than General ... so, Congress made one. John J. Pershing was appointed to the rank General of the Armies, one of only two men to ever have been appointed to that rank. (Three guesses as to who the other was...)

But this was an ad-hoc solution. Pershing was authorized to design a rank insignia for his new post, but never wore more than four stars.

The problem arose again in World War II, for basically the same reason. This time it was worse, since Dwight D. Eisenhower was supposed to be in overall command of the European Theater of Operations. Until late 1944 this wasn't a problem, since Eisenhower was of equal rank with his peers ... but Bernard Montgomery was about to be promoted to Field Marshal.

This ... was a problem. Because, inter-service politics had become rather more complex in the inter-war period.

If Eisenhower were promoted to a new super-grade, the Chief of Staff of the Army, George C. Marshall, would also have to be so promoted. And General MacArthur, the Army commander in the Pacific. And General Arnold, the head of the Army Air Force. And the Navy wasn't about to be left out ... you'd have to advance the Navy men in equivalent positions to equivalent rank.

So, Congress would have to create two new ranks. The Navy rank, Fleet Admiral, was obvious. There was a brief consideration given to naming the Army rank Field Marshal. Field Marshal Eisenhower ... has a nice ring to it. Field Marshal MacArthur. Yes, that might work, too. But then they got to Field Marshal Marshall, and Marshall was not amused. (And who can blame him? Go ahead, try to say it without snickering.) So, the new Army rank was to be called General of the Army.

By the end of 1944, three men were promoted to Fleet Admiral: William D. Leahy, Ernest J. King, and Chester W. Nimitz. Four men were promoted to General of the Army: George C. Marshall, Douglas MacArthur, Dwight D. Eisenhower, and Henry H. Arnold. Two additional appointments were made to that rank, for Fleet Admiral William Halsey and General of the Army Omar Bradley, but none have been appointed since. (It is interesting to note that the most senior five-star officer -- by date of rank -- was a Navy man. The Navy has always been held to be the senior service. Army people don't like to hear that, but there it is...)

(By the way -- Ray Spruance was robbed. He should have gotten Fleet Admiral. But that's beside the point.)

With that said, it should be readily apparent why no new appointments to General of the Army will be made. None of our allies have any serving officers of a rank higher than our full General, so an American General is a peer in all respects to any general officer of an allied service. If the British were to elevate one of their officers serving in the Middle East to Field Marshal, we'd have a legitimate discussion. But since that's vanishingly unlikely, General Petraeus will most likely never hold a rank higher than the one he currently possesses.

Now, if he successfully pulls our fat out of the fire in Afghanistan, it might not be wrong to let him carry a fifth star with him into retirement. I don't think that'd be out of line. It just isn't necessary right now. And that rank, historically, has been all about necessity.

Friday, July 02, 2010

Video Del Fuego, Part XXX

The incomparable Dave Brubeck had his 89th birthday recently. Most of the performers who were active in the late '50s and early '60s are gone, but he's still active. It's an inspiration, knowing that this man has stayed so active, so long. I only discovered his music about ten years ago, but it's amazing stuff. It's a half-century old, some of it, but it sounds as if it could have been written yesterday.

Here's a performance by the Dave Brubeck Quartet from 1966.