Tuesday, November 13, 2012

We had Everything in the World Drop Out

Here's a sad thought: as of 2010, more than half the country was not yet alive when America landed on the Moon. Folks my age, the people who witnessed the Apollo missions, are the exception, not the rule.

As such, the Apollo missions are a matter of remote history, consigned in popular culture to the same ranks of historic ignorance as the War of 1812 or the life of William H Taft.

Historical trivia: Tom Hanks didn't go to the Moon
with Kevin Bacon and Bill Paxton.

Surveyor 3 was the first spacecraft to
purposefully dig a trench on the Moon.
That doesn't include all the spacecraft that accidentally
dug a trench on impact.
Most people have a poor understanding of the history of Apollo. Their limited knowledge is derived almost exclusively from motion pictures such as Ron Howard's Apollo 13, a movie that, while accurate in most details, left behind a general idea that the only Bad Thing that ever happened on the way to the Moon was the Apollo 13 mission. The movie also gave the impression that Apollo astronauts were merely helpless passengers on a deep space journey, constantly hoping and praying that ground crews would come up with ideas to rescue them.

In fact, NASA's astronauts were not only veteran test pilots, but skilled aeronautical engineers, capable of diagnosing complex electrical systems and flight navigation software. The mission immediately prior to Apollo 13 put these myriad skills to the test in a life or death situation, just moments after launch. And the entire near cataclysm was witnessed by no less an audience than the President of the United States, 43 years ago on November 14, 1969.

The Apollo 12 mission was designed to be the first manned lunar landing with a precise target destination in mind. Unlike Armstrong and Aldrin's goal of merely landing on the flattest part of the Moon, astronauts Pete Conrad and Alan Bean would aim for a 300 square yard touchdown zone near the landing site of the unmanned Surveyor 3 spacecraft. The mission would test the limits of the crew's navigating and piloting skills, as well as the hardware's computing and event handling abilities.

Cmdr. Pete Conrad was arguably the best choice to lead this mission. The veteran naval aviator and test pilot had previously crewed the long-duration Gemini 5 mission, as well as the Gemini 11 Agena docking mission, a flight that briefly made Conrad and copilot Richard Gordon record holders for having traveled farthest from planet Earth. Conrad was a comedian and a prankster, but he also had a reputation for keeping a cool head and working through problems, even during the most dire emergencies. He was reliable when situations were no longer "nominal."

Don't disappoint the President.
Launch weather on the morning of Apollo 12's scheduled liftoff was hardly nominal. An advancing front had pushed a low cloud deck over Merritt Island during the evening, and set visibility conditions at the brink of flight rule acceptability. Unfortunately for NASA, politics sometimes trumped caution. President Richard Nixon, Chief Executive of the United States and holder of the Pen of Budget Appropriations Approval was in town for the launch that day, and to disappoint someone who was in charge of deciding the future of the agency would be an unwise move. So, despite the dodgy weather, the all-Navy crew was loaded into the 365-ft tall Saturn V and the countdown continued in the rain.

At T-0:00, with 7.5 million pounds of thrust, Apollo 12 thundered off the launch pad into the clouds. Just thirty seconds later, the ship would go transonic, pushing through maximum aerodynamic pressure inside the storm.
Launch commit... liftoff!
 Thirty six and one half seconds into the flight, the Something Bad part happened. Here's a transcript:

000:00:37 Gordon (onboard): What the hell was that?
000:00:38 Conrad (onboard): Huh?
000:00:39 Gordon (onboard): I lost a whole bunch of stuff; I don't know.

What happened was that a bolt of lightning seared through the clouds and the spacecraft, riding the trail of rocket vapor back to the launch pad. A second bolt of lightning repeated the journey a few seconds later.

000:00:50 Gordon (onboard): I can't see; there's something wrong.
000:00:51 Conrad (onboard): AC Bus 1 light, all the fuel cells-
000:00:56 Conrad (onboard): I just lost the platform.

Conrad was looking at a mess on his control panel. Every possible alarm signal was lit. The entire electrical system, previously being powered by fuel cells in the Apollo Service Module, seemed to be out. The navigation system (the pilots' familiar 8-ball) was spinning endlessly in a useless gimbal lock. And still the ship hadn't exploded... yet. Either the alarms were wrong or they were about to experience the first out-of-control Moonship. Conrad briefly explained the situation to Mission Control.

000:01:02 Conrad: Okay, we just lost the platform, gang. I don't know what happened here; we had everything in the world drop out.

Gordon, the Command Module Pilot, didn't think it was a hardware problem, but he wasn't sure what to do about the instrumentation problem.

000:01:09 Gordon (onboard): I can't - There's nothing I can tell is wrong, Pete.

000:01:12 Conrad: I got three fuel cell lights, an AC bus light, a fuel cell disconnect, AC bus overload 1 and 2, Main Bus A and B out.

This was no way to get to the Moon. Apollo 12 hadn't reached orbit yet - - they still were low enough to use their Launch Escape Tower and abort the mission. Conrad fingered the abort handle on the arm of his chair and pondered options.
Artist - astronaut Al Bean's interpretation of that moment.
 In the right-hand seat, Lunar Module Pilot Al Bean noodled through the dials on his side of the ship. Bean spotted a voltage indicator from the fuel cells that showed there was still energy in the system.  
000:01:21 Bean (onboard): I got AC.
000:01:22 Conrad (onboard): We got AC?
000:01:23 Bean (onboard): Yes.
000:01:24 Conrad (onboard): Maybe it's just the indicator. What do you got on the main bus?
000:01:26 Bean (onboard): Main bus is - The volt indicated is 24 volts.

Twenty four volts wasn't enough to run the mission, but it also meant that the electricity might be shorting out somewhere in the panel or in one of the circuits. The question was how to isolate the electrical problem without detonating the tons of fuel just behind them that was in the process of shoving them toward the Moon.
EECOM and veteran chain smoker John Aaron.
In Houston, a  NASA physics major named John Aaron suddenly realized this scenario was somewhat familiar. Aaron was the Electrical, Environmental and Consumables Manager (EECOM) for this flight, and he had seen a launch problem like this during a mission simulation back in 1968. The problem was that the primary equipment used to convert hardware electrical loads to power levels that could be read by the monitoring dials (known as "signal conditioning equipment") was broken. Fortunately, Apollo was equipped with backup, auxiliary equipment. Aaron knew the problems with all the different system alarms could be fixed with the flick of a switch. Aaron keyed his microphone to talk to CAPCOM Gerry Carr. "Try SCE to AUX," he said.

Astronaut CAPCOM Gerry Carr had no idea what that sentence meant. Neither did Flight Director Gerry Griffith, serving as Flight Director on his very first mission. "Tell them that," he told Carr.

000:01:36 Carr: Apollo 12, Houston. Try SCE to auxiliary. Over.
000:01:39 Conrad: Try FCE to Auxiliary. What the hell is that?
000:01:41 Conrad: NCE to auxiliary...

Carr corrected Conrad:

000:01:43 Carr: SCE, SCE to auxiliary.

Conrad also never heard that command before this mission. Fortunately, Al Bean knew what they were talking about. Bean had been part of the same simulation run that John Aaron remembered, and knew where the switch was on the many confusing panels of the Command Module. Al turned the switch, and the control panel reset itself. 

000:01:48 Bean (onboard): It looks - Everything looks good.
000:01:50 Conrad (onboard): SCE to Aux.
000:01:52 Gordon (onboard): The GDC is good.

Guidance and telemetry were back online, or rather, the astronauts were now able to see what Guidance and telemetry was trying to tell them. Conrad didn't have to pull the abort handle and stop the mission. Immediate crisis averted, they finally had time to take in what had just happened:
000:06:43 Gordon (onboard): Man, oh man ...
000:06:44 Bean (onboard): Isn't that a ...
000:06:45 Conrad (onboard): Wasn't that a Sim[ulation] they ever gave us?
000:06:46 Gordon (onboard): Jesus!
000:06:50 Conrad (onboard): [Laughter].
000:06:51 Gordon (onboard): That was something else. I never saw so many...
000:06:52 Conrad (onboard): [Laughter].
000:06:54 Gordon (onboard): ...There were so many lights up there, I couldn't even read them all.
000:06:55 Conrad (onboard): [Laughter].
000:06:57 Gordon (onboard): There was no sense reading them because there was - I was - I was looking at this; Al was looking over there ...
000:07:02 Conrad (onboard): Everything looked great [laughter] except we had all the lights on...
High-speed  launchpad cameras revealed the twin lightning strikes
that nearly wrecked the mission.

An amazing, terrifying moment that could have easily ended in failure, or tragedy. Instead, the training and skill of the crew and support staff managed to avert disaster. Oh, and they did manage to land right next to that Surveyor spacecraft just five days later.
Mission Accomplished

Me and Captain Girlfriend with
CAPCOM Gerry Carr, who later flew on Skylab 4


No comments:

Post a Comment