This Day In Space April 13, 1970


By KD Martin

In 1969, a group of astronauts change the world.  They ride the biggest rocket ever built to the Moon.  It's the culmination of 10 years of space pioneering, and the foundation of four decades of exploring worlds beyond our own.  Join us for the ongoing story of our greatest adventure.

© 2010 John C. Dvorak Cage Match


The launch of Apollo 13


The Service Module explosion, painting by Alan Bean


The Crew of Apollo 13, Lovell - CDR, Swigert - CMP (replaced Mattingly) and Haise LMP

Courtesy Alan Bean and NASA  Click each to enlarge↔


This Day In Space, April 13, 1970

The Apollo 13 mission launched on April 11, 1970 at 13:13 CST.

The mission began with a little-known malfunction: during the second-stage boost, the center (inboard) engine shut down two minutes early. The four outboard engines burned longer to compensate, and the vehicle continued to a successful orbit. The shutdown was determined to be due to dangerous pogo oscillations that might have torn the second stage apart.

Two days later, en route to the Moon, a fault in the electrical system of one of the Service Module's oxygen tanks produced an overpressure rupture which caused a loss of electrical power and failure of both oxygen tanks. The Command Module remained functional on its own batteries and oxygen tank, which were only designed to support the vehicle during the last hours of flight. The crew shut down the Command Module and used the Lunar Module as a "lifeboat" during the return trip to earth. Despite great hardship caused by limited power, loss of cabin heat, shortage of potable water, and the critical need to jury-rig the carbon dioxide removal system, the crew returned safely to Earth on April 17, and the mission was termed a "successful failure".

The first two days the crew ran into a couple of minor surprises, but generally Apollo 13 was looking like the smoothest flight of the program. At 46 hours, 43 minutes  Joe Kerwin, the CapCom on duty, said, "The spacecraft is in real good shape as far as we are concerned. We're bored to tears down here." It was the last time anyone would mention boredom for a long time.

At 55 hours, 46 minutes, as the crew finished a 49-minute TV broadcast showing how comfortably they lived and worked in weightlessness,  Lovell stated,"This is the crew of Apollo 13 wishing everybody there a nice evening, and we're just about ready to close out our inspection of Aquarius (the LM) and get back for a pleasant evening in Odyssey (the CM). Good night."

Nine minutes later, oxygen tank No. 2 blew up, causing the No. 1 tank also to fail. The Apollo 13 command modules normal supply of electricity, light, and water was lost, and they were about 200,000 miles from Earth.

Thirteen minutes after the explosion,  Lovell happened to look out of the left-hand window, and saw the final evidence pointing toward potential catastrophe. "We are venting something out into the.. into space," he reported to Houston.  Jack Lousma, the CapCom replied, "Roger, we copy you venting."  Lovell said, "It's a gas of some sort." It was oxygen gas escaping at a high rate from the second, and last, oxygen tank.

Ground controllers in Houston faced a formidable task. Completely new procedures had to be written and tested in the simulator before being passed up to the crew. The navigation problem had to be solved; essentially how, when, and in what attitude to burn the LM descent engine to provide a quick return home.  Without the LM, the accident would certainly have been fatal.

After an intensive investigation, the Apollo 13 Accident Review Board identified the cause of the explosion. In 1965 the CM had undergone many improvements, which included raising the permissible voltage to the heaters in the oxygen tanks from 28 to 65 volts DC. Unfortunately, the thermostatic switches on these heaters weren't modified to suit the change. During one final test on the launch pad, the heaters were on for a long period of time. "This subjected the wiring in the vicinity of the heaters to very high temperatures (1000 F), which have been subsequently shown to severely degrade teflon insulation. The thermostatic switches started to open while powered by 65 volts DC and were probably welded shut." Furthermore, other warning signs during testing went unheeded and the tank, damaged from 8 hours overheating, was a potential bomb the next time it was filled with oxygen. That bomb exploded on April 13, 1970 -- 200,000 miles from Earth.




Click picture for video and watch in full screen





Click picture for video, set hi-def (480p) and watch in full screen


Article Courtesy NASA and KDM

Today's trivia question:

When Jim Lovell, on the Lunar return, asked Ken Mattingly, who had been scrubbed from the mission and replaced by Jack Swigert if "the flowers were blooming in Houston," to what was he referring?

I haven't a clue. Great post though.

Today's trivia question:

What was really radioed to Houston when the O2 tank exploded?  This is one of the most famous misquotes of Apollo history.  "Houston..."

I remember it as "Houston, we have a problem here."

Based on your question, I'd better google. Actually, the misquote in this case is close enough. There's no difference in meaning. Here's the audio on youtube. For any who click before they guess, clicking disqualifies your guess, of course.

No more Google.  Today's trivia question:

Something blew up, which was almost expected, when Apollo 13 was enroute back to Earth from the Moon.  What was it?  What did the explosion force the crew to do?

The winner gets to suggest the next TDIS topic.

Was it something in the LEM that caused them to reenter the command module, which was required for reentry anyway? (I've already suggested a TDIS topic to you by email. I suspect you would have used it with or without my suggestion.)

KD,

Sorry, unlike you, I am not a professional astronomers with the memory of a computer, at least not a working computer.