Apollo 13 There are 240,000 miles of empty space between the earth and the moon. That's equivalent to 99 trips around the world. The temperatures of that empty, darkened void can vary from 240 degrees F. above zero to 240 degrees F. below zero, depending upon exposure to the sun. It's a harsh and deadly environment for beings accustomed to Earth's comfortable embrace. On April 11, 1970, Jack Swigert, Fred Haise, and James Lovell-the crew of the NASA mission, Apollo 13-were propelled from the Earth's surface, destined for the moon. But fifty-six hours into the journey-some 200,000 miles from earth-Ground Control, in Texas, heard those compelling words, "Houston, we've had a problem here." The message came at 9:08 PM, on April 13th. An oxygen tank in the service module had exploded. The explosion had blown off the cover to the #4 bay, destroying one oxygen tank, and damaging a second. The astronauts, peering out the windows of the command module, observed a cloud of gas venting into space. Suddenly warning lights indicated the loss of two of three fuel cells. Without the fuel cells, the command module-the mother ship-would soon die. In communication with Houston, and with only 15 minutes of power left in the command module, the three astronauts were directed, for their own safety, to enter the adjoining lunar module. With their visions of a moon landing now dashed and with the lunar module now serving as their temporary habitation, the astronauts' first concern was for their basic survival. How long could they sustain life in this little compartment? The lunar module was built for only a 45-hour lifetime. Now that would need to be stretched to at least 90. It was designed to support only two men for two days. Now it was being asked to care for three men for nearly four days. A sufficient oxygen supply was present to meet their physical needs. Food and water, though, would have to be carefully rationed. All non-critical systems were turned off to reduce unnecessary power consumption. If their present calculations for reentry into the earth's atmosphere were correct, they estimated water supplies would be completely depleted five hours prior to splashdown. Diminishing intake to a fifth of the normal amount and risking dehydration, the crew drank but six ounces of liquid per person per day. After a day and a half in the lunar module, a warning light showed that carbon dioxide had accumulated to a life-threatening level. Removing the build-up from the module was a major concern. The lithium hydroxide canisters available were designed to remove CO2, but the square canisters of the command module were incompatible with the round openings of the lunar system. Working feverishly to bring the team home safely, Mission Control devised, and communicated, a way to attach the command module's square canisters over the round conduits of the lunar system, using plastic bags, cardboard, and tape-materials all found on-board. Resolving one crisis after another, the crew still faced the daunting dilemma of how to return to earth. The lunar module navigation system wasn't devised to do this. And after having made a midcourse correction to comply with their potential lunar landing, the crew now struggled to plot navigation for their realignment with a return-to-Earth trajectory. Five hours after the initial oxygen explosion, as the crew approached the moon, Houston directed two engine burns to facilitate a safer and more rapid return to earth. The first was a 35-second burn of one of the engines designed for the lunar landing. This would propel them into orbit around the moon. The second, a five-minute burn from the same lunar module engine would take place two hours after rounding the far side of the Moon. The formidable challenge facing the crew prior to the second burn was that a precise navigational path for their return trajectory had to be in order. The control module's platform alignment had been transferred to the lunar module, but verifying accuracy was difficult. Due to the explosion in the service module, a swarm of debris that followed the craft made it impossible to sight real stars that could be used for setting navigation. An idea came from Ground Control to use the sun as an alignment star, knowing nothing could block out its light. Realizing this to be their only reliable option, the crew carefully rotated the spacecraft to the attitude Houston directed. If they were correct, the Sun should be centered in the sextant. The crew faced the daunting reality that ground control would have no way of accurately communicating the correct calculations to insure their safe travel home. The crew would be required to figure that on their own. If Houston's estimation were right, the sun would be in place before them. If the sun were not in the right place, the crew could not accurately set a trajectory alignment to establish a path for reentry into earth's atmosphere. If their figures were incorrect, the second burn would hurl them off track, into outer space. The sun had to be there, precisely at the place and time needed. Houston waited anxiously as Lovell set his bearings and looked through the Alignment Optical Telescope. Suddenly the crew erupted in cheers! There it was! They were correct. The sun was positioned exactly where they needed it! Cheers from Ground Control immediately joined those of the crew. The alignment with the Sun proved to be less than one-half degree off, and with those measurements calculated, the second burn propelled them accurately toward the earth. Now it would be a matter of surviving the remaining 142 hours of the voyage. As the journey continued, the physical challenges became more and more apparent. The trip was marked with discomfort beyond the lack of food and water. When the electrical systems were turned off, the craft lost an important source of heat. Swigert's feet were wet, and being without lunar overshoes, he suffered in the cold. When the temperature in the module dropped to 38 degrees, the Teflon-coated in-flight coveralls were frigid to the touch and sleep was almost impossible. Still other challenges faced the crew. The service module was dead. The control module had no power. The lunar module, which they occupied, had no heat shield required to enter the Earth's atmosphere. With Houston, the three astronauts desperately worked to resolve these dilemmas. Four hours prior to their hopeful landing, and before entering the Earth's atmosphere, the crew dispatched the service module. Mission Control had insisted on retaining it until the last possible moment in order to shelter the control module's heat shield. To the crew, this was their first view of the actual damage to the craft. With one whole panel missing, and wreckage protruding, they watched it as it drifted away into space. Three hours later the astronauts reentered the control module, and having carefully powered it up after its long, cold sleep, they sealed the hatch behind them and jettisoned the lunar module into the surrounding darkness. Apollo 13 blazed into the Earth's atmosphere in a splash of light across the heavens. With the interior walls of the control module covered with condensation, upon deceleration in the upper atmosphere, it rained on the astronauts inside. Once in the earth's atmosphere, the greatest challenge facing the crew was physical exhaustion. Lovell, alone, had lost 14 pounds in the ordeal. It was now a matter of being able to stay awake through to the end of the mission. Approaching the point of splashdown, the parachutes deployed according to plan, and near midday, April 17th, the crew safely landed in the Pacific Ocean off the shores of Samoa. Incredibly, the accuracy of the reentry and touchdown were among the most precise of the entire Apollo program. To the astronauts and ground control of Apollo 13, failure was not an option. Were Lovell, Swigert or Haise air-headed optimists? Absolutely not! Were the members of the Ground Control staff hard-hearted realists who gave up on the problem? Definitely not! They were some of the toughest men you'll ever meet. When Houston heard those words, "we've had a problem," they quickly immersed themselves in a world of new thought and action. They never gave up until there was a resolution to each and every challenge those astronauts faced. They didn't spend time focused on what wouldn't work, rather they directed their energies and attentions to what would solve the crisis. And they succeeded because of their tough-minded optimism. Finding one partial solution after another, ground-control guided Lovell, Haise, and Swigert safely home, and with margin to spare!
Regards Dominic Burford BSc Hons MBCS CITP Third Party Developer Program Senior Software Engineer * Tel: +44 (0) 1536 495074 * dominic.burford <BLOCKED::mailto:[EMAIL PROTECTED]> @pegasus.co.uk "I conclude that there are two ways of constructing a software design: One way is to make it so simple there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies." -- Tony Hoare, Turing Award Lecture 1980 ______________________________________________________________________ Pegasus Software Limited is an Infor company. This e-mail is from Pegasus Software Limited. The e-mail and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom it is addressed. If you have received this e-mail in error you must not copy, distribute or take any action in reliance on it. Please notify the sender by e-mail or telephone. Pegasus Software Limited utilises an anti-virus system and therefore any files sent via e-mail will have been checked for known viruses. You are however advised to run your own virus check before opening any attachments received as Pegasus Software Limited will not in any event accept any liability whatsoever once an e-mail and/or any attachment is received. This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ --- StripMime Report -- processed MIME parts --- multipart/alternative text/plain (text body -- kept) text/html --- _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://leafe.com/mailman/listinfo/profox OT-free version of this list: http://leafe.com/mailman/listinfo/profoxtech ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
