Monday, February 23, 2015

What Could Have Been

Way back in the earliest days of the Apollo Program, they had no clue how to do the job they'd been handed. When President Kennedy laid down the gauntlet to put a man on the Moon by the end of the decade, America had a grand total of fifteen minutes and twenty-two seconds of spaceflight experience, and didn't even have a man-rated orbital rocket yet.

The most obvious, and in some ways the technically safest approach would be to build a ginormous rocket and lift the whole thing -- lander, earth-return stage, and capsule -- all in one heave. They called that approach Direct Ascent.

In the end, they decided against that approach. As it happened, if you split the earth-return capsule totally apart from the lander, you could save weight on both. That means you don't need such an enormous rocket, and the overall project cost is lower.

And besides which ... the Direct Ascent version of the Apollo 13 scenario is grim. No separate LM spacecraft means no lifeboat, and no lifeboat means three dead astronauts.

But we can still imagine what might have been. Seferino Rengel has used the Orbiter space simulator to visualize what it would have looked like.

Looks great ... but, on the whole, it's just as well we didn't go this route.

The great thing about Orbiter is that you can take a walking tour of designs that never were. You can appreciate the aesthetics, and sometimes come to a realization about why we didn't take that branch. Direct Ascent was just one example. Another example is the Lockheed Star Clipper. The pilot in me looks at that beautiful lifting body and drools ... but the engineer looks at that fuel tank layout and screams "Foam strikes ahoy!"

Another great thing about Orbiter is that we can imagine things that we could be doing, but for whatever reason aren't. Take the Grand Tour, for instance. When I was young, I assumed that this was a once-in-a-lifetime thing, that you'd never see such a fortuitous alignment again. Not so fast! For Jupiter and Saturn, at least, that alignment repeats every so often, and you can get one of Uranus or Neptune into the act as well. Such an alignment is available ... oh, right about now. Had we been more alert on the trigger, we could have something like Eris Explorer on deck and ready to go.

The mission plan is breathtaking in its vision, and optimism. The Eris encounter would be in 2051. I'll be 84 years old, making the bold and possibly unwarranted assumption that I last that long. When we go -- and we will, I'm sure of it -- the senior scientists and engineers on the project will simply have to accept that they won't survive to see the project come to fruition. They will have to hand it off to a new generation to bring it all together at the target. They'll have to assume that the organizations will still be viable entities throughout the entire duration of the mission. That the sponsor governments will stay the course, and provide funding for the whole course.

I find such optimism encouraging. When we plant a field that our sons and daughters will harvest, we make an investment in their future. And we can't invest in a future that we don't believe in.

National Engineers Week is February 22nd through the 28th. If you can read this, thank a teacher. If you can read this in English, thank a veteran. But if you can read this on a computer, thank an engineer.

Friday, February 13, 2015

Sesquicentennial, Part XLIII: Looking Ahead, Looking Back


One hundred years ago, the Western Front had settled down into an awful stalemate. A system of trenches stretched from the Swiss border to the North Sea, and the land in between the trenches had been turned into a churn of mud by the combined efforts of German, Austrian, French, and British artillery. The men in those trenches probably thought to themselves that surely, no such vision of Hell had been brought to Earth before.

Except that, if any of them had thought to cast their sight back fifty years in time and two thousand miles to the west, they'd see quite clearly that it had.

The Siege of Petersburg was, in many ways, a preview of coming attractions.

Trenches? Check. Massive artillery pounding the Hell out of everything in sight? Check. Crazy plans to dig mines under the enemy works and pack them with explosives? Good God yes, check. People had every right to feel despair, disgust, dread, or any number of other emotions regarding what the Western Front had become ... but they had no right at all to feel surprised. The Western Front was really nothing more than Petersburg scaled up to fit a continent.

Granted, the Western Front nightmare lasted a good bit longer. But that's partly because Douglas Haig wasn't fit to stand in the company of either Grant or Sherman.

True, Lee was keeping Grant's army out of both Petersburg and Richmond. He was also pinned down there, unable to do anything but hold those two cities. He was also unable to keep Grant from extending his lines around Petersburg to the south, and Richmond to the north.

That was eventually going to be a problem.

You see, there was more to Sherman's plan than simple bloody-minded violence. Part of that can be seen by a modification to a map of Confederate railroads (the original can be found here).

Sherman's approximate line of march since jumping off in Spring 1864 is shown in orange. By mid-February, Sherman had reached the city of Columbia in South Carolina. That encounter ... went poorly for Columbia. Sherman claimed that he didn't order Columbia burnt to the ground ... but he wasn't exactly sorry it happened, either. That's neither here nor there, though; the main point I want to make is that he was exacting the maximum amount of damage possible against the Confederacy's ability to move supplies from where they were to where they weren't. Where they were tended to be the farms where food was grown and the shops where goods were made, and where they weren't was the Army of Northern Virginia.

Lee had exactly one life-line left open. And that was the rail line from Richmond to Danville. This had been recently connected to Greensboro in North Carolina, so in theory Lee could draw on supplies from points south ... except that due to Sherman's efforts, there wasn't much further south from which to draw.

This is more or less the point in a chess match at which you'd resign.

You resign in a chess match when you see the inevitable outcome, and know that no matter what move you make, even if you make the best move possible from your current position, you will lose. Your opponent will put your King in checkmate, and there's nothing you can do about it.

But Jefferson Davis was at least in nominal control, and he wasn't in a resigning mood. Was this stubborn pride, delusional lunacy, or some mix of the two? Because Davis had to have known the jig was well and truly up. Had to. He was a West Point man himself, and had enough military experience out on the sharp end to know what's what. But pride ... his pride would not allow him to admit he'd been beaten. Nor would it allow him to breathe a word of defeatism to another living soul.

No, surrender wasn't a word in Davis' vocabulary. So long as it was up to him, he'd grind it out to the last desperate inch.

And so it would go.