Tuesday, April 12, 2011

T+50: Poyekhali!

[Ed. Note: Another anniversary from 1861 is here. And another anniversary from 1981 is here.]

Fifty years ago...

By April 12, 1961, only fifteen successful launches into orbit had been made. Today, the Soviet Union would attempt to make that total sixteen. They would also up the ante by putting a human being on top of the rocket. The Americans were planning to do much the same thing, of course. But, for reasons I've discussed earlier, they would be too late to claim the honor of being first.

(Actually, it's a slightly different problem. The orbital phase of Mercury was paced by the availability of the Atlas booster, which wasn't quite ready for prime time yet.)

It is interesting to compare and contrast the Mercury and Vostok capsules. Each vehicle shows basic design traits that would carry down into their descendents. The Mercury capsule was designed to sit snugly on top of a Redstone or Atlas missile. It was a streamlined, conical shape, and served as its own fairing for getting through the atmosphere. Space and mass were at an absolute premium, so the capsule barely had enough room for its pilot. It was sometimes said that you didn't climb into a Mercury capsule, so much as you wore it.

The Russians weren't quite so tight on mass constraints, since they had more powerful rockets at their disposal. But, they didn't bother to streamline their capsule at all. It might have never occurred to them to do so. "It's a spaceship," they'd probably say. "It operates in vacuum. Why in the world would you bother to streamline it? Just put a fairing over it for the first few minutes, and it's all good." This design trend would continue with the Soyuz capsule, still in use.

It's also interesting to compare and contrast astronaut selection and training techniques. Many of the training methods were similar, insofar as no one knew precisely what to expect. They wanted to select men who would cope well with the unexpected. The similarity ended there, though. The Americans decided to start with experienced test pilots, since they were already in excellent physical condition, and had proven their ability to cope with ... unusual working environments. You knew the men you picked could handle themselves in a crisis. The ones who couldn't, didn't last long as test pilots.

The Russians went another route entirely. They started with young, physically robust military pilots; then they trained them to be cosmonauts. Their main concern was whether or not a man could endure space flight at all. Famously, the manual controls on Vostok were behind a locked panel. This wasn't because the Russians didn't trust their pilots to land where they were told to. It was because the engineers weren't sure that, after hours in free-fall, a man would still have the faculties necessary to control the spacecraft. It was a safety feature. As it happens, the locks would only be used for the first flight, after which they were decided unnecessary. The original plan called for the codes to be radioed up to the cosmonaut if they were needed. "But, what if the radio goes out?" Well, they put the codes in an envelope that the cosmonaut could open when directed. The cosmonaut detachment commander, Nikolai Kamanin, thought that was a stupid idea. He decided that he'd give his man the code before launch, and trust him not to use it unless it was an emergency.

Two men were training for that first flight. One was Gherman Titov, an Air Force pilot who excelled at gymnastics. The other was Yuri Gagarin, another Air Force pilot, slightly older and slightly more experienced than Titov. The decision on who would fly was not made until the morning of the mission. Gagarin was chosen, partly because he was older and seen as more stable, a steady man who would not panic.

At about 7AM local time, Gagarin was bolted into the Vostok capsule. This brings up another difference between Vostok and Mercury: Vostok had no escape tower. It was not believed to be necessary, since the pilot was already equipped with an ejection seat. They couldn't make a parachute big enough to slow down the capsule enough for a survivable landing, so they decided that the pilot would punch out and land on his own parachute. This would serve double-duty as the pilot's emergency escape if anything should go wrong with the launch.

Gagarin was calm as they worked their way through the pre-launch checklist. Then, at seven past nine local time, the final count began.

Less than ten minutes later, Vostok 1 was in orbit. It would be another 25 minutes before ground control had gathered enough data to be certain that it was a stable orbit. Not that it mattered much at this point. Stable or not, Vostok 1 was committed. The only large engine left was the one intended to de-orbit the spacecraft before re-entry.

Vostok had a beautifully-ingenious device for orienting the spacecraft prior to deorbit. Orientation is crucial. You have to have the spacecraft's engine pointing in exactly the right direction, else you waste thrust. Assuming a circular orbit, all you need to do is make sure you're level, and pointed backwards. The Vzor device did this, with a window and some mirrors. The mirrors reflected the horizon such that it was visible all around the window's edge. So, if you were oriented level, you saw the horizon all around the edge of the window. Then, you look at the clouds rolling past the window. If they're going from the bottom straight to the top, bingo! Otherwise, you slew around in yaw until they line up.

Gagarin didn't have to do any of this by hand, though. The automatic systems worked quite well, and were perfectly able to line up and execute the de-orbit burn without direct intervention. But, there was one small problem. One of the pyro bolts had failed, and the re-entry capsule was still connected to the service module by a bundle of cables. The two halves began re-entry above Egypt, and Gagarin began to experience wild gyrations. He didn't mention this to ground control, for two reasons. One, he didn't think he was in serious trouble. And two, what could they do about it anyway? It's not like they could send up bolt-cutters.

As it happens, Gagarin's instincts were spot-on. The cable burned in two, and re-entry proceeded normally. At seven kilometers altitude, the hatch was released, and Gagarin punched out. He landed under his own parachute, and greeted the two startled farmers who met him with a request for a telephone to call Moscow.

Only an hour and a half had passed, but the world would be forever different. Man had taken his first halting steps into the Universe.

(You can recreate this for yourself, with Orbiter 2010, as demonstrated in the clip above. It's a fascinating experience.)

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