{"id":168412,"date":"2019-05-02T13:08:00","date_gmt":"2019-05-02T17:08:00","guid":{"rendered":"https:\/\/www.nasa.gov\/?migration=converted-node-444520"},"modified":"2023-08-21T17:46:46","modified_gmt":"2023-08-21T21:46:46","slug":"50-years-ago-apollo-10-passes-countdown-demonstration-test","status":"publish","type":"post","link":"https:\/\/www.nasa.gov\/history\/50-years-ago-apollo-10-passes-countdown-demonstration-test\/","title":{"rendered":"50 Years Ago: Apollo 10 Passes Countdown Demonstration Test"},"content":{"rendered":"\n<p>Two weeks before the Apollo 10 launch, engineers at Kennedy Space Center\u2019s Launch Complex 39B worked to overcome a problem with the Saturn V rocket\u2019s first stage. On April 28, 1969, a planned power outage to conduct maintenance at the Launch Control Center also caused power to be lost at the launch pad, where not all systems had backup power. The rocket\u2019s first stage was loaded with its flight load of RP-1 fuel, and the loss of power caused the failure of pneumatic controls keeping prevalves at the bottom of the tank closed and the prevalves opened, spilling 5,280 liters of RP-1 fuel onto the launch pad\u2019s flame trench. Since the fuel tank didn\u2019t have any relief valves to allow air to enter the tank as fuel drained out, the loss of fluid volume caused the top of the tank to dimple inward. Quick thinking engineers at the pad instituted a work around to refill the tank and the dimple popped out with a very audible \u201cboomp.\u201d Launch pad manager John J. \u201cTip\u201d Talone concluded of the quick action, \u201cIt worked like a champ.\u201d Concern with any possible cracks in the fuel tank was resolved through non-destructive testing and visual inspections. <\/p>\n\n\n\n<p><img decoding=\"async\" loading=\"lazy\" width=\"475\" height=\"353\" src=\"https:\/\/www.nasa.gov\/wp-content\/uploads\/2019\/05\/apollo_10_crew_photo_s69-32613.jpg\" alt=\"apollo_10_crew_photo\">\u00a0 <img decoding=\"async\" loading=\"lazy\" width=\"281\" height=\"353\" src=\"https:\/\/www.nasa.gov\/wp-content\/uploads\/2019\/05\/apollo_10_on_pad_39b_cddt_may_6_1969_s69-33860.jpg\" alt=\"apollo_10_on_pad_39b_cddt_may_6_1969\"><br> <em>Left: Apollo 10 astronauts (left to right) Cernan, Stafford, and Young. Right: Apollo 10 Saturn V during the CDDT.<\/em><\/p>\n\n\n\n<p>The fuel spill incident occurred during Apollo 10\u2019s Countdown Demonstration Test (CDDT), a full dress rehearsal for the actual countdown to launch that consisted of two parts. The wet test included fueling the rocket as if for flight, with the countdown cutting off just prior to first stage engine ignition, and did not involve the flight crew. This was followed by the dry test, an abbreviated countdown without fueling the rocket but with the flight crew boarding the Command Module (CM) as if on launch day. The wet countdown was completed on May 5, and the dry test the next day, with astronauts Thomas P. Stafford, Eugene A. Cernan, and John W. Young suiting up and climbing aboard their CM Charlie Brown. As launch day approached, the trio were spending many hours in the CM and Lunar Module (LM) simulators, rehearsing various aspects of their upcoming mission. Controllers in Mission Control at the Manned Spacecraft Center, now the Johnson Space Center in Houston, participated in many of the simulations.<\/p>\n\n\n\n<p><img decoding=\"async\" loading=\"lazy\" width=\"458\" height=\"361\" src=\"https:\/\/www.nasa.gov\/wp-content\/uploads\/2019\/05\/ap10-69-h-653hr.jpg\" alt=\"ap10-69-h-653hr\">\u00a0 <img decoding=\"async\" loading=\"lazy\" width=\"288\" height=\"367\" src=\"https:\/\/www.nasa.gov\/wp-content\/uploads\/2019\/05\/apollo_10_young_stafford_ksc_sim_may_1969_s69-34341.jpg\" alt=\"apollo_10_young_stafford_ksc\"><br><em>Left: Cernan about to enter the LM simulator, with mascot Snoopy looking on. Right: Young (left) and Stafford about to enter the CM simulator.<\/em><\/p>\n\n\n\n<p>Looking beyond the first Moon landing, NASA\u2019s preparations were well underway for Apollo 12, the second attempt expected to occur about four months after the first. Flight hardware for this mission continued arriving at KSC with the S-IC first stage being delivered on May 3. Four days later, workers in the Vehicle Assembly Building (VAB) erected that stage on its Mobile Launch Platform. Stacking of the second and third stages took place later in the month. The <a href=\"https:\/\/www.nasa.gov\/feature\/50-years-ago-nasa-names-apollo-12-crew\">Apollo 12 crew<\/a> of Charles \u201cPete\u201d Conrad, Alan L. Bean, and Richard F. Gordon had begun their training including a two-day geology field trip to Big Bend, Texas, in early May.<\/p>\n\n\n\n<p><img decoding=\"async\" loading=\"lazy\" alt=\"apollo_12_s-ic_erection\" src=\"https:\/\/www.nasa.gov\/wp-content\/uploads\/2019\/05\/apollo_12_s-ic_erection_may_7_1969_19690507-01_s69-34675.jpg\" width=\"362\" height=\"284\">  <img decoding=\"async\" loading=\"lazy\" alt=\"shepard_apollo_10_splashdown\" src=\"https:\/\/www.nasa.gov\/wp-content\/uploads\/2019\/05\/shepard_apollo_10_splashdown_in_mcc_may_26_1969_s69-35183.jpg\" width=\"369\" height=\"284\"><br>\n<em>Left: First stage of the Apollo 12 Saturn V in the VAB. Right: Shepard in Mission Control after the Apollo 10 splashdown.<\/em><\/p>\n\n\n\n<p>On May 5, 1969, Alan B. Shepard marked the eighth anniversary of his suborbital Mercury-Redstone-3 mission, during which he became the first American in space. Two days later, Shepard had more reason to celebrate \u2013 flight surgeons returned him to full space flight status. Shepard was grounded in 1963 when he developed Meniere\u2019s disease, an inner ear condition that causes dizziness. A minor operation in 1968 corrected the problem and Shepard remained symptom-free. Said Shepard of his return to flight status, \u201cThe sooner I get off the ground, the better.\u201d He went on to command Apollo 14 in 1971, becoming the only Mercury 7 astronaut to walk on the Moon.<\/p>\n\n\n\n<p>Read <a href=\"https:\/\/historycollection.jsc.nasa.gov\/JSCHistoryPortal\/history\/oral_histories\/SSP\/talonejj.htm\" rel=\"noopener\">Talone<\/a>\u2019s oral history with the <a href=\"https:\/\/historycollection.jsc.nasa.gov\/JSCHistoryPortal\/history\/\" rel=\"noopener\">JSC History Office<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Two weeks before the Apollo 10 launch, engineers at Kennedy Space Center\u2019s Launch Complex 39B worked to overcome a problem with the Saturn V rocket\u2019s first stage. On April 28, 1969, a planned power outage to conduct maintenance at the Launch Control Center also caused power to be lost at the launch pad, where not [...]<\/p>\n","protected":false},"author":74,"featured_media":174127,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"nasa_hds_core_meta_l10n":"en-US","nasa_hds_core_meta_article_editor":"","nasa_hds_core_meta_article_contacts":[],"nasa_hds_core_meta_article_topic":"","nasa_hds_core_meta_linked_locations":[],"nasa_hds_core_meta_article_related_articles":[],"hds_migrate_meta_pr_release_id":"","hds_migrate_meta_pr_release_type":"","nasa_hds_core_meta_location_x":"","nasa_hds_core_meta_location_y":"","nasa_hds_core_meta_gallery_images":[],"footnotes":""},"categories":[2671,2713,2932],"news-tags":[],"internal-terms":[12664],"coauthors":[11996],"parsely":{"version":"1.1.0","meta":{"@context":"https:\/\/schema.org","@type":"NewsArticle","headline":"50 Years Ago: Apollo 10 Passes Countdown Demonstration Test","url":"https:\/\/www.nasa.gov\/history\/50-years-ago-apollo-10-passes-countdown-demonstration-test\/","mainEntityOfPage":{"@type":"WebPage","@id":"https:\/\/www.nasa.gov\/history\/50-years-ago-apollo-10-passes-countdown-demonstration-test\/"},"thumbnailUrl":"https:\/\/www.nasa.gov\/wp-content\/uploads\/2019\/05\/apollo_10_crew_photo_s69-32613.jpg?w=150&h=150&crop=1","image":{"@type":"ImageObject","url":"https:\/\/www.nasa.gov\/wp-content\/uploads\/2019\/05\/apollo_10_crew_photo_s69-32613.jpg"},"articleSection":"NASA History","author":[{"@type":"Person","name":"John Uri"}],"creator":["John Uri"],"publisher":{"@type":"Organization","name":"NASA","logo":"https:\/\/www.nasa.gov\/wp-content\/themes\/nasa\/assets\/images\/nasa-logo.svg"},"keywords":["Missions","Apollo","Apollo 10","NASA History"],"dateCreated":"2019-05-02T17:08:00Z","datePublished":"2019-05-02T17:08:00Z","dateModified":"2023-08-21T21:46:46Z"},"rendered":"<meta name=\"parsely-title\" content=\"50 Years Ago: Apollo 10 Passes Countdown Demonstration Test\" \/>\n<meta name=\"parsely-link\" content=\"https:\/\/www.nasa.gov\/history\/50-years-ago-apollo-10-passes-countdown-demonstration-test\/\" \/>\n<meta name=\"parsely-type\" content=\"post\" \/>\n<meta name=\"parsely-image-url\" content=\"https:\/\/www.nasa.gov\/wp-content\/uploads\/2019\/05\/apollo_10_crew_photo_s69-32613.jpg?w=150&h=150&crop=1\" \/>\n<meta name=\"parsely-pub-date\" content=\"2019-05-02T17:08:00Z\" \/>\n<meta name=\"parsely-section\" content=\"NASA History\" \/>\n<meta name=\"parsely-tags\" content=\"Missions,Apollo,Apollo 10,NASA History\" \/>\n<meta name=\"parsely-author\" content=\"John Uri\" \/>","tracker_url":"https:\/\/cdn.parsely.com\/keys\/nasa.gov\/p.js"},"read_time":4,"time_ago":"5 years","featured_image":{"id":174127,"file":"https:\/\/www.nasa.gov\/wp-content\/uploads\/2019\/05\/apollo_10_crew_photo_s69-32613.jpg","title":"apollo_10_crew_photo_s69-32613","alt":"apollo_10_crew_photo","caption":""},"_links":{"self":[{"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/posts\/168412"}],"collection":[{"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/users\/74"}],"replies":[{"embeddable":true,"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/comments?post=168412"}],"version-history":[{"count":3,"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/posts\/168412\/revisions"}],"predecessor-version":[{"id":494463,"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/posts\/168412\/revisions\/494463"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/media\/174127"}],"wp:attachment":[{"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/media?parent=168412"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/categories?post=168412"},{"taxonomy":"news-tags","embeddable":true,"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/news-tags?post=168412"},{"taxonomy":"internal-terms","embeddable":true,"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/internal-terms?post=168412"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.nasa.gov\/wp-json\/wp\/v2\/coauthors?post=168412"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}