{"id":13454,"date":"2018-12-10T00:54:01","date_gmt":"2018-12-09T16:54:01","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/delta-4-heavy-countdown-aborted-moments-before-launch\/"},"modified":"2018-12-10T00:54:01","modified_gmt":"2018-12-09T16:54:01","slug":"delta-4-heavy-countdown-aborted-moments-before-launch","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/delta-4-heavy-countdown-aborted-moments-before-launch\/","title":{"rendered":"Delta 4-Heavy countdown aborted moments before launch"},"content":{"rendered":"<p><iframe loading=\"lazy\" src=\"https:\/\/player.vimeo.com\/video\/305286884\" width=\"678\" height=\"381\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p><em><strong>Video credit: United Launch Alliance<\/strong><\/em><\/p>\n<p>A dramatic automatic abort 7.5 seconds before the planned liftoff of a United Launch Alliance Delta 4-Heavy rocket Saturday night kept the towering launcher on the pad at Vandenberg Air Force Base, California, with a top secret spy payload for the National Reconnaissance Office.<\/p>\n<p>The 233-foot-tall (71-meter) rocket was counting down to launch at 8:15 p.m. PST Saturday (11:15 p.m. EST; 0415 GMT Sunday), but an automated sequencer detected a technical issue and triggered an abort.<\/p>\n<p>\u201cHold hold hold,\u201d a member of the ULA launch team declared on the countdown net.<\/p>\n<p>A burst of flame appeared at the base of the rocket, a normal occurrence in the final seconds of a Delta 4 countdown as sparklers activate near the engines to burn off excess hydrogen gas before ignition, a measure aimed at eliminating the risk of a fireball or explosion.<\/p>\n<p>It was not immediately clear whether any of the rocket\u2019s three Aerojet Rocketdyne RS-68A main engines started their ignition sequences, but a statement later released by ULA said the computer-controlled countdown sequencer ordered an abort at T-minus 7.5 seconds.<\/p>\n<p>In the statement, ULA said the abort was \u201cdue to an unexpected condition during terminal count at approximately 7.5 seconds before liftoff.<\/p>\n<p>\u201cThe team is currently reviewing all data and will determine the path forward. A new launch date will be provided when available,\u201d ULA said.<\/p>\n<p>The Delta 4-Heavy is made up of three Delta 4 first stage boosters bolted together, each with an RS-68A engine burning liquid hydrogen and liquid oxygen propellants. ULA commands the three RS-68A engines to start in a staggered sequence, beginning with the starboard engine at T-minus 7 seconds, followed two seconds later by ignition of the center and port engines.<\/p>\n<p>The timing of the abort at T-minus 7.5 seconds suggests the countdown stopped around a half-second before the first of the Delta 4-Heavy\u2019s three main engines was supposed to ignite.<\/p>\n<p>ULA\u2019s launch team quickly \u201csafed\u201d the rocket, disarmed ordnance, and drained the Delta 4-Heavy of its supply of cryogenic propellants. The launch team did not set a new target launch date, but officials were instructed to plan for an extended turnaround after Saturday night\u2019s scrub, and the Delta 4-Heavy flight was expected to be delayed at least a few days.<\/p>\n<p>A similar cutoff in the final seconds of a Delta 4 countdown in 2010 resulted in a three-day slip to resolve the problem responsible for the abort \u2014 and replace the hydrogen burn-off sparklers on the pad \u2014 before the rocket successfully launched from Cape Canaveral with a GPS navigation satellite.<\/p>\n<p>The upcoming mission from Vandenberg, located around 140 miles (225 kilometers) northwest of Los Angeles, is&nbsp;codenamed NROL-71 by the National Reconnaissance Office, which owns the U.S. government\u2019s classified intelligence-gathering satellites. The NRO has not released any information about the spacecraft aboard the Delta 4-Heavy, but independent observers of NRO space launches believe the payload is heading for an unusual, high-inclination orbit, and is likely a new Keyhole-type high-resolution optical imaging satellite, with an Earth-pointing telescope capable of capturing extremely detailed imagery of sites around the world for review by government intelligence analysts.<\/p>\n<p>The Delta 4-Heavy is ULA\u2019s biggest rocket, and can loft up to 51,950 pounds (23,560 kilograms) of payload mass to a 120-mile-high (200-kilometer) low Earth orbit inclined 90 degrees to the equator.<\/p>\n<p>The heavy-lift variant of the Delta 4 rocket has launched 10 times to date. The NROL-71 mission will be the 11th flight of a Delta 4-Heavy, and the 38th mission overall for the Delta 4 family since November 2002. It will also be ULA\u2019s ninth and final launch of the year, following five Atlas 5 launches, a pair of Delta 4s, and the final liftoff of the company\u2019s now-retired Delta 2 rocket.<\/p>\n<p>A launch attempt for the NROL-71 mission Friday night was scrubbed after the Delta 4 team encountered a problem with a communications link between the control center and the rocket associated with the holdfire system.<\/p>\n<p><b><i>Email the author.<\/i><\/b><\/p>\n<p><em><strong>Follow Stephen Clark on Twitter: @StephenClark1.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Video credit: United Launch Alliance A dramatic automatic abort 7.5 seconds before the planned liftoff of a United Launch Alliance Delta 4-Heavy rocket Saturday night kept the towering launcher on the pad at Vandenberg Air Force Base, California, with a top secret spy payload for the National Reconnaissance Office. The 233-foot-tall (71-meter) rocket was counting [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[864,1878,2790,1688,1408,25,257,848],"class_list":["post-13454","post","type-post","status-publish","format-standard","hentry","category-news","tag-aerojet-rocketdyne","tag-delta","tag-delta-382","tag-delta-4","tag-delta-4-heavy","tag-launch","tag-military-space","tag-national-reconnaissance-office"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/13454"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=13454"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/13454\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=13454"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=13454"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=13454"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}