{"id":56,"date":"2007-02-11T16:19:13","date_gmt":"2007-02-11T21:19:13","guid":{"rendered":"http:\/\/www.thehistoricalarchive.com\/happenings\/the-apollo-13-accident-chronology-of-events\/"},"modified":"2007-02-11T16:21:38","modified_gmt":"2007-02-11T21:21:38","slug":"the-apollo-13-accident-chronology-of-events","status":"publish","type":"post","link":"http:\/\/www.thehistoricalarchive.com\/happenings\/56\/the-apollo-13-accident-chronology-of-events\/","title":{"rendered":"The Apollo 13 Accident &#8211; Chronology of Events"},"content":{"rendered":"<div class=\"147322a129097e1fa44d6732c925fd6d\" data-index=\"1\" style=\"float: none; margin:10px 0 10px 0; text-align:center;\">\n<script type=\"text\/javascript\"><!--\r\ngoogle_ad_client = \"ca-pub-8134560547846945\";\r\n\/* 468x60 tha *\/\r\ngoogle_ad_slot = \"1487607395\";\r\ngoogle_ad_width = 468;\r\ngoogle_ad_height = 60;\r\n\/\/-->\r\n<\/script>\r\n<script type=\"text\/javascript\"\r\nsrc=\"http:\/\/pagead2.googlesyndication.com\/pagead\/show_ads.js\">\r\n<\/script>\n<\/div>\n<p><a href=\"http:\/\/www.thehistoricalarchive.com\/products\/Apollo-13-15-and-16-62.html\"><img decoding=\"async\" align=\"right\" src=\"http:\/\/www.thehistoricalarchive.com\/covers\/a129.jpg\" title=\"\" alt=\"\" \/><\/a>The below timestamped commentary documents the Apollo 13 accident from about 2 minutes before the accident began to about 5 minutes after the accident. The time sequence is given in Ground elapsed time &#8211; the time elapsed from the liftoff of Apollo 13 on April 11, 1970. To help with the time perspective, 55:52:00 G.E.T. is the same as 10:05 PM EST on April 13,1970.<br \/>\n55:52:31 &#8211; Master caution and warning triggered by low hydrogen pressure in  tank no. 1<\/p>\n<p>55:52:58 &#8211; CapCom (Jack Lousma): &#8220;13, we&#8217;ve got one more item  for you, when you get a chance. We&#8217;d like you to stir up the cryo tanks. In  addition, I have shaft and trunnion &#8230;..<\/p>\n<p>55:53:06 &#8211; Swigert:  &#8220;Okay.&#8221;<\/p>\n<p>55:53:07 &#8211; CapCom: &#8220;&#8230;. for looking at Comet Bennett, if you  need it.&#8221;<\/p>\n<p>55:53:12 &#8211; Swigert: &#8220;Okay. Stand by.&#8221;<\/p>\n<p>55:53:18 &#8211; Oxygen  tank No. 1 fans on.<\/p>\n<p>55:53:19 &#8211; Oxygen tank No. 2 pressure decreases 8  psi.<\/p>\n<p>55:53:20 &#8211; Oxygen tank No. 2 fans turned on.<\/p>\n<p>55:53:20 &#8211;  Stabilization control system electrical disturbance indicates a power  transient.<\/p>\n<p>55:53:21 &#8211; Oxygen tank No. 2 pressure decreases 4  psi.<\/p>\n<p>55:53:22.718 &#8211; Stabilization control system electrical disturbance  indicates a power transient.<\/p>\n<p>55:53:22.757 &#8211; 1.2 Volt decrease in ac bus 2  voltage.<\/p>\n<p>55:53:22.772 &#8211; 11.1 amp rise in fuel cell 3 current for one  sample<\/p>\n<p>55:53:26 &#8211; Oxygen tank No. 2 pressure begins rise lasting for 24  seconds.<\/p>\n<p>55:53:38.057 &#8211; 11 volt decrease in ac bus 2 voltage for one  sample.<\/p>\n<p>55:53:38.085 &#8211; Stabilization control system electrical  disturbance indicates a power transient.<\/p>\n<p>55:53:41.172 &#8211; 22.9 amp rise in  fuel cell 3 current for one sample<\/p>\n<p>55:53:41.192 &#8211; Stabilization control  system electrical disturbance indicates a power transient.<\/p>\n<p>55:54:00 &#8211;  Oxygen tank No. 2 pressure rise ends at a pressure of 953.8  psia.<\/p>\n<p>55:54:15 &#8211; Oxygen tank No. 2 pressure begins to  rise.<\/p>\n<p>55:54:30 &#8211; Oxygen tank No. 2 quantity drops from full scale for 2  seconds and then reads 75.3 percent.<\/p>\n<p>55:54:31 &#8211; Oxygen tank No. 2  temperature begins to rise rapidly.<\/p>\n<p>55:54:43 &#8211; Flow rate of oxygen to  all three fuel cells begins to decrease.<\/p>\n<p>55:54:45 &#8211; Oxygen tank No. 2  pressure reaches maximum value of 1008.3 psia.<\/p>\n<p>55:54:51 &#8211; Oxygen tank No.  2 quantity jumps to off-scale high and then begins to drop until the time of  telemetry loss, indicating failed sensor.<\/p>\n<p>55:54:52 &#8211; Oxygen tank No. 2  temperature sensor reads -151.3 F.<\/p>\n<p>55:54:52.703 &#8211; Oxygen tank No. 2  temperature suddenly goes off-scale low, indicating failed  sensor.<\/p>\n<p>55:54:52.763 &#8211; Last telemetered pressure from oxygen tank No. 2  before telemetry loss is 995.7 psia.<\/p>\n<p>55:54:53.182 &#8211; Sudden accelerometer  activity on X, Y, Z axes.<\/p>\n<p>55:54:53.220 &#8211; Stabilization control system  rate changes begin.<\/p>\n<p>55:54:53.323 &#8211; Oxygen tank No. 1 pressure drops 4.2  psi.<\/p>\n<p>55:54:53.500 &#8211; 2.8 amp rise in total fuel cell  current.<\/p>\n<p>55:54:53.542 &#8211; X, Y, and Z accelerations in CM indicate 1.17g,  0.65g, and 0.65g.<\/p>\n<p>55:54:53.555 &#8211; Master caution and warning triggered by  DC main bus B undervoltage. Alarm is turned off in 6 seconds. All indications  are that the cryogenic oxygen tank No. 2 lost pressure in this time period and  the panel separated.<\/p>\n<p>55:54:54.741 &#8211; Nitrogen pressure in fuel cell 1 is  off-scale low indicating failed sensor.<\/p>\n<p>55:54:55.350 &#8211; Telemetry  recovered.<\/p>\n<p>55:54:56 &#8211; Service propulsion system engine valve body  temperature begins a rise of 1.65 F in 7 seconds. DC main A decreases 0.9 volts  to 28.5 volts and DC main bus B 0.9 volts to 29.0 volts. Total fuel cell current  is 15 amps higher than the final value before telemetry loss. High current  continues for 19 seconds. Oxygen tank No. 2 temperature reads off-scale high  after telemetry recovery, probably indicating failed sensors. Oxygen tank No. 2  pressure reads off-scale low following telemetry recovery, indicating a broken  supply line, a tank pressure below 19 psi, or a failed sensor. Oxygen tank No. 1  pressure reads 781.9 psia and begins to drop.<\/p>\n<p>55:54:57 &#8211; Oxygen tank No.  2 quantity reads off-scale high following telemetry recovery indicating failed  sensor.<\/p>\n<p>55:55:01 &#8211; Oxygen flow rates to fuel cells 1 and 3 approached  zero after decreasing for 7 seconds.<\/p>\n<p>55:55:02 &#8211; The surface temperature  of the service module oxidizer tank in bay 3 begins a 3.8 F increase in a 15  second period. The service propulsion system helium tank temperature begins a  3.8 F increase in a 32 second period.<br \/>\n55:55:09 &#8211; DC main bus A voltage recovers to 29.0 volts, DC main bus B  recovers to 28.8.<\/p>\n<p>55:55:20 &#8211; Swigert: &#8220;Okay, Houston, we&#8217;ve had a problem  here.&#8221;<\/p>\n<p>55:55:28 &#8211; Lousma: &#8220;This is Houston. Say again please.&#8221;<\/p>\n<p>55:55:35 &#8211; Lovell: &#8220;Houston, we&#8217;ve had a problem. We&#8217;ve had a main B bus  undervolt.&#8221;<\/p>\n<p>55:55:42 &#8211; Lousma: &#8220;Roger. Main B undervolt.&#8221;<\/p>\n<p>55:55:49  &#8211; Oxygen tank No. 2 temperature begins steady drop lasting 59 seconds indicating  a failed sensor.<\/p>\n<p>55:56:10 &#8211; Haise: &#8220;Okay. Right now, Houston, the voltage  is&#8211;is looking good. And we had a pretty large bang associated with the caution  and warning there. And as I recall, main B was the one that had an amp spike on  it once before.<\/p>\n<p>55:56:30 &#8211; Lousma: &#8220;Roger, Fred.&#8221;<\/p>\n<p>55:56:38 &#8211;  Oxygen tank No. 2 quantity becomes erratic for 69 seconds before assuming an  off-scale low state, indicating a failed sensor.<\/p>\n<p>55:56:54 &#8211; Haise: &#8220;In  the interim here, we&#8217;re starting to go ahead and button up the tunnel  again.&#8221;<\/p>\n<p>55:57:04 &#8211; Haise: &#8220;That jolt must have rocked the sensor on &#8212;  see now &#8212; oxygen quantity 2. It was oscillating down around 20 to 60 percent.  Now it&#8217;s full-scale high.&#8221;<\/p>\n<p>55:57:39 &#8211; Master caution and warning  triggered by DC main bus B undervoltage. Alarm is turned off in 6  seconds.<\/p>\n<p>55:57:40 &#8211; DC main bus B drops below 26.25 volts and continues  to fall rapidly.<\/p>\n<p>55:57:44 &#8211; Lovell: &#8220;Okay. And we&#8217;re looking at our  service module RCS helium 1. We have &#8212; B is barber poled and D is barber poled,  helium 2, D is barber pole, and secondary propellants, I have A and C barber  pole.&#8221; AC bus fails within 2 seconds.<\/p>\n<p>55:57:45 &#8211; Fuel cell 3  fails.<\/p>\n<p>55:57:59 &#8211; Fuel cell current begins to decrease.<\/p>\n<p>55:58:02 &#8211;  Master caution and warning caused by AC bus 2 being reset.<\/p>\n<p>55:58:06 &#8211;  Master caution and warning triggered by DC main bus  undervoltage.<\/p>\n<p>55:58:07 &#8211; DC main bus A drops below 26.25 volts and in the  next few seconds levels off at 25.5 volts.<\/p>\n<p>55:58:07 &#8211; Haise: &#8220;AC 2 is  showing zip.&#8221;<\/p>\n<p>55:58:25 &#8211; Haise: &#8220;Yes, we got a main bus A undervolt now,  too, showing. It&#8217;s reading about 25 and a half. Main B is reading zip right  now.&#8221;<\/p>\n<p>56:00:06 &#8211; Master caution and warning triggered by high hydrogen  flow rate to fuel cell 2.<\/p>\n\n<div style=\"font-size: 0px; height: 0px; line-height: 0px; margin: 0; padding: 0; clear: both;\"><\/div><iframe src=\"http:\/\/www.facebook.com\/plugins\/like.php?href=http%3A%2F%2Fwww.thehistoricalarchive.com%2Fhappenings%2F56%2Fthe-apollo-13-accident-chronology-of-events%2F&amp;layout=standard&amp;show_faces=true&amp;width=450&amp;action=like&amp;colorscheme=light\" scrolling=\"no\" frameborder=\"0\" allowTransparency=\"true\" style=\"border:none; overflow:hidden; width:450px;margin-top:5px;\"><\/iframe>","protected":false},"excerpt":{"rendered":"<p>The below timestamped commentary documents the Apollo 13 accident from about 2 minutes before the accident began to about 5 minutes after the accident. The time sequence is given in Ground elapsed time &#8211; the time elapsed from the liftoff of Apollo 13 on April 11, 1970. To help with the time perspective, 55:52:00 G.E.T. [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_links_to":"","_links_to_target":""},"categories":[8],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"http:\/\/www.thehistoricalarchive.com\/happenings\/wp-json\/wp\/v2\/posts\/56"}],"collection":[{"href":"http:\/\/www.thehistoricalarchive.com\/happenings\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.thehistoricalarchive.com\/happenings\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.thehistoricalarchive.com\/happenings\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.thehistoricalarchive.com\/happenings\/wp-json\/wp\/v2\/comments?post=56"}],"version-history":[{"count":0,"href":"http:\/\/www.thehistoricalarchive.com\/happenings\/wp-json\/wp\/v2\/posts\/56\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.thehistoricalarchive.com\/happenings\/wp-json\/wp\/v2\/media?parent=56"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.thehistoricalarchive.com\/happenings\/wp-json\/wp\/v2\/categories?post=56"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.thehistoricalarchive.com\/happenings\/wp-json\/wp\/v2\/tags?post=56"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}