Thursday, January 21, 2010

Apollo +50: Little Joe 1B

Finally, NASA got had a successful test of the Mercury abort system under maximum dynamic pressure.

I am devoting some space in this blog (pun intended) to covering the 50th anniversary of the start of the space age. 50 years ago today, NASA was 9 years, 5 months, and 30 days away from launching a mission to land a man on the moon and bring him safely back to Earth. Only, nobody at NASA knew this at the time. They were still trying to put a man into space - for a little while at least.

One of the systems that they wanted to test before putting a human on the top of a rocket was whether the astronaut would survive an abort at that point in the lanch when the rocket would be under the most stress. This was determined by the speed at which the rocket was traveling and the thickness of the atmosphere it was flying through.

Above the point of maximum dynamic pressure - or max-Q - the atmosphere grew sufficiently thin that it did not put much pressure on the space craft. Below the point of max-Q the rocket was travelling more slowly and that meant less dynamic pressure. At the point of max-Q the speed had gotten high enough and the atmosphere was still thick enough to put the greatest load on the rocket.

If the astronaut could survive this, he should have no trouble surviving an abort either before or after that point.

Well . . . assuming everything else worked.

For this test, NASA also decided to get a little extra data by putting a live passenger on board - a Rhesus monkey by the name of Miss Sam. The Max-Q test was originally designed to test how the rocket held up under an abort under max-Q. But how well would the astronaut hold up?

In this test, Miss Sam became disoriented for about 30 seconds after the abort sequence was triggered. He had been trained to perform a set of tasks throughout the mission. When the abort rockets fired to carry the capsule away from the rocket, she quit performing those tasks and failed to respond to commands. Thirty seconds later, she was back to doing her tasks.

However, this caused NASA officials to worry that an astronaut would react in the same way. This was a problem because the astronaut was the designated backup for a chute deployment failure. If the capsule did not deploy the parachutes automatically during an abort, the astronaut was supposed to be available to deploy the chutes manually. If the astronaut was too shaken up by the abort itself to do the job, then he would not serve as a reliable backup.

This result did not imply that the mission was a failure. In fact, a part of the success of this mission was that it produced useful data such as this - and Miss Sam and the capsule did survive the Max-Q test.

The rocket launched, the abort system activated at Max-Q. The capsule splashed down into the ocean. The Navy recovered the capsule. Mss Sam was taken out of the capsule and examined and shown to be in good health.

At this point, NASA decided to move past the use of test capsules and to start flight-testing the man-rated capsules - the capsules designed to carry astronauts into space.

We will have to wait six months until the next test. However, when these tests start up again, they will begin a run that will end up in putting men in space, then in orbit, then on the moon, in nine and a half years.

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