{"id":12132,"date":"2020-11-05T01:04:16","date_gmt":"2020-11-04T17:04:16","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/ula-scrubs-atlas-5-launch-as-spacex-readies-repaired-rocket-for-gps-mission\/"},"modified":"2020-11-05T01:04:16","modified_gmt":"2020-11-04T17:04:16","slug":"ula-scrubs-atlas-5-launch-as-spacex-readies-repaired-rocket-for-gps-mission","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/ula-scrubs-atlas-5-launch-as-spacex-readies-repaired-rocket-for-gps-mission\/","title":{"rendered":"ULA scrubs Atlas 5 launch as SpaceX readies repaired rocket for GPS mission"},"content":{"rendered":"
\"\"
A United Launch Alliance Atlas 5 rocket stands on pad 41 at Cape Canaveral Air Force Station on Tuesday, Nov. 3. Credit: United Launch Alliance<\/figcaption><\/figure>\n

United Launch Alliance called off the planned launch of an Atlas 5 rocket Wednesday at Cape Canaveral to resolve a problem with valves at the launch pad, while a SpaceX team a mile-and-a-half to the south readied a Falcon 9 rocket for liftoff Thursday evening with a GPS navigation satellite for the U.S. military.<\/p>\n

ULA\u2019s launch team scrubbed the Atlas 5 launch attempt Wednesday shortly before 6 p.m. EST (2300 GMT) after unsuccessful attempts to fix the valve issue, first remotely and then with a team of technicians dispatched to the Atlas 5\u2019s seaside launch pad.<\/p>\n

The Atlas 5 rocket will carry a classified payload into orbit for the National Reconnaissance Office, the U.S. government\u2019s spy satellite agency. The launch is designated NROL-101, and the NRO has not disclosed any specifics about the payload\u2019s mission, other than it will help the agency in its mission to collect and disseminate information for the government\u2019s intelligence agencies.<\/p>\n

ULA started the Atlas 5\u2019s countdown late Wednesday morning, powered up the rocket, and proceeded with guidance system testing and other checkouts before loading cryogenic propellants into the launcher ahead of a planned liftoff at 5:54 p.m. EST (2254 GMT).<\/p>\n

But the launch team stopped the countdown clock after an \u201cunexpected system response from remotely commanded ground system liquid oxygen valves,\u201d ULA said in a statement.<\/p>\n

\u201cThe team continues to analyze the system and will protect for our next launch attempt no earlier than Nov. 6,\u201d ULA said.<\/p>\n

The next opportunity to launch the Atlas 5 rocket will be Friday, ULA said. An exact time for Friday\u2019s launch attempt was not immediately announced, but the mission\u2019s launch time has moved about four minutes earlier per day. That would put Friday\u2019s launch time at around 5:46 p.m. EST (2246 GMT).<\/p>\n

The Atlas 5\u2019s launch was previously scheduled for Tuesday, but ULA returned the rocket to its vertical hangar near the launch pad to replace an environmental control system duct feeding conditioned air to the top secret NRO payload on top of the 206-foot-tall (63-meter) vehicle.<\/p>\n

Ground crews returned the Atlas 5 to its launch pad late Tuesday in preparation for the launch attempt Wednesday.<\/p>\n

Before the next Atlas 5 launch opportunity, SpaceX plans to launch a Falcon 9 rocket from nearby pad 40 during a 15-minute window opening at 6:24 p.m. EST (2324 GMT) Thursday.<\/p>\n

The 229-foot-tall (70-meter) Falcon 9 rocket was standing on pad 40 Wednesday in preparation for launch Thursday evening. Pad 40 is located about a mile-and-a-half (2.5 kilometers) south of the Atlas 5 launch pad at Cape Canaveral.<\/p>\n

\"\"
A SpaceX Falcon 9 rocket stands on pad 40 at Cape Canaveral Air Force Station on Nov. 4. Credit: Stephen Clark \/ Spaceflight Now<\/figcaption><\/figure>\n

The Falcon 9 rocket is poised to loft the GPS 3 SV04 navigation satellite for the U.S. Space Force, replenishing the fleet of positioning and timing stations used by billions of military and civilian users around the world.<\/p>\n

SpaceX tried to launch the GPS satellite Oct. 2, but an engine problem forced an automatic abort just two seconds prior to liftoff.<\/p>\n

Engineers investigating the Oct. 2 abort found that two of the nine first stage engines on the rocket had a tendency to ignite a split-second earlier than expected. Inspections showed a blocked relief valve in the gas generators of the two engines caused pressures to rise sooner than designed at startup, and sensors on the engines detected the problem and halted the countdown.<\/p>\n

SpaceX engineers identified a masking treatment inadvertently left behind in two Merlin engines as the cause of the aborted countdown last month.<\/p>\n

\u201cWhen we looked at the data, we saw that two of the engines attempted to start early, and the auto abort prevented that,\u201d said Hans Koenigsmann, SpaceX\u2019s vice president of build and flight reliability. \u201cAnd by doing that, it prevented a possible hard start that could have been damaging to the engine hardware.\u201d<\/p>\n

The Merlin engines power up with help from an igniter fluid known as TEA-TEB \u2014 or triethylaluminium-triethylborane \u2014 that gives off a bright green flash at the start pf the ignition sequence.<\/p>\n

\u201cAnd then we have liquid oxygen, and we have kerosene, or RP-1 as its called,\u201d Koenigsmann said last week in a conference call with reporters. \u201cAnd you need to introduce these liquids in the right order. If you do this in the wrong order, if you happen to throw in the liquid oxygen and the RP-1 and the igniter fluid, then what would happen is we call it a hard start.\u201d<\/p>\n

A hard start would \u201crattle\u201d the engine in most cases, but could cause damage, Koenigsmann said. \u201cSo in general, you do not want that. You want a good startup.\u201d<\/p>\n

SpaceX shipped the Merlin engines back to a test site in Central Texas, where inspections revealed a substance blocking a line leading to a pressure relief valve in the gas generator on two of the engines.<\/p>\n

Koenigsmann said the vent port, which means just one-sixteenth of an inch wide, was obstructed by a hardened masking lacquer. He said liquid lacquer \u2014 similar to red nail polish \u2014 is used by a third-party vendor that anodizes aluminum engine components for SpaceX.<\/p>\n

The lacquer protects certain parts during the anodizing treatment process, but the vendor \u2014 which officials did not identify \u2014 is supposed remove the material before shipping the components to SpaceX for engine manufacturing.<\/p>\n

The gas generator on each Merlin engine drives a turbopump feeding kerosene and liquid oxygen propellants into the main combustion chamber.<\/p>\n

Engineers at SpaceX\u2019s McGregor test site demonstrated that the engines performed normally after removing the blockage from the vent valve. Koenigsmann said the issue was \u201cvery subtle, but can have obviously some negative impact on the engine operation.\u201d<\/p>\n

\u201cThe GPS 3-4 mission will still use the same booster as for the first launch attempt\u201d said Walt Lauderdale, GPS 3-4 mission director from the Space Force\u2019s Space and Missile Systems Center. \u201cThe two engines which gave rise to the launch abort were replaced with ones confirmed through inspection and pedigree review to not have any residual masking lacquer.\u201d<\/p>\n

SpaceX and Space Force officials verified all nine Merlin engines on the Falcon 9 rocket were ready for flight after a test-firing on pad 40 Saturday.<\/p>\n

Besides the rocket for the GPS mission, the engine issue has also affected vehicles for a pair of upcoming NASA launches. So far, the problem has only impacted missions slated to use new Falcon 9 boosters.<\/p>\n

The first operational flight of SpaceX\u2019s Crew Dragon spaceship is set for liftoff Nov. 14 from the Kennedy Space Center with three NASA astronauts and a Japanese mission specialist to kick off a half-year expedition on the International Space Station.<\/p>\n

SpaceX is replacing two Merlin engines on the Falcon 9 rocket for the Crew Dragon mission that engineers found suffered from the same early startup tendency exhibited by the engines on the rocket for the GPS mission. The problem delayed the Crew Dragon launch from Oct. 31 to Nov. 14.<\/p>\n

Steve Stich, NASA\u2019s commercial crew program manager, said last week that the agency\u2019s engineers want to analyze engine data from the GPS launch before clearing the Crew Dragon for liftoff later this month.<\/p>\n

The engine problem has also delayed the launch of the U.S.-European Sentinel-6 Michael Freilich oceanography satellite from Vandenberg Air Force Base in California. That mission was originally supposed to blast off Nov. 10, but is now scheduled for launch Nov. 21.<\/p>\n

Email the author.<\/i><\/b><\/p>\n

Follow Stephen Clark on Twitter: @StephenClark1.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

A United Launch Alliance Atlas 5 rocket stands on pad 41 at Cape Canaveral Air Force Station on Tuesday, Nov. 3. Credit: United Launch Alliance United Launch Alliance called off the planned launch of an Atlas 5 rocket Wednesday at Cape Canaveral to resolve a problem with valves at the launch pad, while a SpaceX […]<\/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":[724,2003,1736,1708,479,2004,2015,2016],"class_list":["post-12132","post","type-post","status-publish","format-standard","hentry","category-news","tag-atlas-5","tag-av-090","tag-complex-40","tag-complex-41","tag-falcon-9","tag-gem-63","tag-gps","tag-gps-3-4"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/12132"}],"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=12132"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/12132\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=12132"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=12132"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=12132"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}