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| Damaged Apollo 13 Module. Photo courtesy of www.nasa.gov. |
So, the movie "Gravity" failed to win best picture at the 86th Academy Awards. The winner of best picture this year, "Twelve Years a Slave," was a very good movie and deserved it more anyway, in my opinon. But, if you are disappointed, here is some barbecue related space age information that may make you feel a little better.
Apollo thirteen was supposed to be the third landing on the moon by American astronauts. Two days into the journey to the moon, an oxygen tank exploded crippling the spacecraft and seriously endangering the lives of the astronauts James Lovell, Mission Commander, Jack Swigert, Command Module pilot and Fred Haise, the Lunar Module Pilot. There is no doubt that the tireless and heroic efforts of the astronauts and the ground support crew saved Apollo thirteen and safely returned it to earth six days after embarking on their ill-fated mission. But, there is one other "hero" in all this that you probably never heard about: American barbecue.
The proper courses of action to resolve the many crises that arose during the Apollo thirteen mission were not always clear or without dispute. For example, one discussion among mission control personnel became particularly heated after Max Faget suggested that the crew perform a maneuver required to manage the temperature of the spacecraft by pointing out "That ship's had one side pointing to the sun and one pointing out to space for hours." The reply was "Do you have any idea what kind of pressure it's going to put on the crew to ask them to execute a PTC (passive thermal control) roll now?" Another chimed in "Or what kind of pressure it's going to put on the available power? I'm not sure we can afford to try something like that at the moment."
For several minutes there was a lively argument at the flight director's station as each person fiercely argued their position. Finally, Flight Director Gene Kranz stepped in saying, "Gentlemen, I thank you for your input. The next job for this crew will be to execute a passive thermal roll. After that, they will power down their spacecraft. And finally, they will get some sleep. A tired crew can get over fatigue, but if we damage this ship any further, we're not going to get over that."
Max Faget's original suggestion that caused all of that lively debate was
"That ship's had one side pointing to the sun and one pointing out to space for hours. If we don't get some kind of barbecue roll going soon, we're going to freeze half our systems and cook the other half."
Apollo spacecraft were protected first by a mylar foil coating that was applied to most surfaces. The second level of protection was the barbecue roll. This was a maneuver the spacecraft made as it coasted to and from the moon. It rotated slowly along its roll axis in order to disperse the heat from the sun so that it evenly and gently heated the spacecraft. The idea for this maneuver was inspired by watching barbecue cooks turning meat to prevent it from scorching.
When cooking barbecue over hot coals, it is important to flip the meat or spin it on a spit as it cooks. This does the same for barbecue that it did for the Apollo spacecraft. It evenly disperses heat so that there is no overheating or under heating. The temperature is even on all sides. The thought for Apollo spacecraft was, if it worked for barbecue, it will work for the Apollo spacecraft too. And, it did.
Apollo astronauts had to perform many tasks in order to successfully complete their missions. There were times when they had to tend to fuel cells and eliminate water in some systems. One of the most important tasks was making sure the thermal operation of the spacecraft was being done well. In the Apollo program, that mode of operation was called barbecue mode. The technical name of the
maneuver is the Passive Thermal Control (PTC) maneuver. During an Apollo 7 test in 1968, NASA learned "During translunar and transearth flight on future missions, it would be necessary to put the spacecraft into a slow “barbecue” roll to maintain an even external temperature." This maneuver, called "the barbecue roll," was first successfully tested twice on Apollo 7.
After Apollo, the barbecue roll was also employed by space shuttle crews too.
So, that's how barbecue helped save Apollo thirteen. The same principle that barbecue cooks use to barbecue a pig on a spit over coals to ensure that it doesn't scorch was also what was chosen by NASA to protect astronauts and the spacecraft in which they were traveling.
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| A Virginia barbecue c. 1900 doing the "barbecue roll." |
