Following Orbital ATK successful test-firing of an Orion launch abort system (LAS) abort motor at their Promontory facility in Utah on June 15, two more qualification tests will be required before the vital crew safety element is officially ready to fly with crewed Space Launch System (SLS) missions, beginning with Exploration Mission -2 (EM-2) mission in the early 2020s.
\nLAS:<\/p>\n
The solid propellant rocket motor is designed to quickly pull the Orion spacecraft\u2019s crew module (CM) away from its launch vehicle in an emergency, either on the launch pad or during the early part of launch.<\/p>\n
The June 15 quick, five-second ground firing, called Qualification Motor-1 (QM-1), tested changes to the motor\u2019s reduced thrust profile and used a special test configuration to collect additional acoustic data.<\/p>\n
Test parameters:<\/p>\n
The abort motor was fired in the T-93 test facility at Promontory, with the test occurring on-time at 1 pm Mountain Daylight Time on June 15.<\/p>\n
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Abort motors are configured in a vertical, upside-down orientation for ground tests at Promontory. As the designation indicates, QM-1 was the first qualification test of the abort motor using a design that is largely expected to be the one used for crewed Orion flights beginning with the Exploration Mission-2 (EM-2) flight planned for early in the next decade on the Space Launch System (SLS) launch vehicle.<\/p>\n
One of the primary objectives of the test was to qualify the new thrust profile. The thrust profile was changed from earlier motors by changing the grain design, reducing the thrust from 500,000 to 400,000 pounds.<\/p>\n
\u201cOriginally, the motor was 500,000 pounds of thrust and it produced [a maximum of] sixteen g\u2019s,\u201d Dr. Roger McNamara, Director of the Orion Launch Abort System for Lockheed Martin, explained, \u201cso when it pulls off with a fully loaded crew module with crew [on-board], it accelerated [at] 16gs.<\/p>\n
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\u201cIt puts a lot of stress not only on the crew, but it puts it on the vehicle itself. When we moved away from the Ares rocket and now we\u2019ve gone to SLS, SLS does not achieve the same type of velocities as quickly. So that allowed us to go take a look at that.<\/p>\n
\u201cNow this motor will [produce] 400,000 pounds of thrust, so it reduces the loads down to probably around 12 or 13 gs and that will be easier on the crew but [also] on the crew module, the weld joints, all the avionics, and everything that is inside the crew module, it doesn\u2019t put as much stress on them, so we don\u2019t have to test them [to] as high [requirements].<\/p>\n
\u201cSo it helps us out with all the qualification of all the components and the overall system.<\/p>\n
\u201cThere\u2019s a couple of big deals out of this. Yes, we brought the g\u2019s down, but we have a lot of components out there that we\u2019re trying to validate and to qualify.<\/p>\n
\u201cThat\u2019s all the avionics, right down to the chips, the components inside \u2014 they\u2019ve all got to be able to handle the abort loads. So by going from sixteen down to thirteen, we\u2019re also reducing a lot of the cost out of the system because we\u2019re not driving failure [requirements] and then building to something that we don\u2019t need to design and build to.\u201d<\/p>\n
As with full-scale SLS booster test-firings, the abort motor is being tested at edges of its required operating temperature range. This test conditioned the motor to the upper end of the range.<\/p>\n
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\u201cTo qualify the motor under high temperature limits, the mean bulk temperature of the propellant is supposed to be a hundred degrees [Fahrenheit] or higher,\u201d Steve Sara, Orbital ATK\u2019s Launch Abort Motor Program Director said prior to the test.<\/p>\n
In contrast to the large boosters, conditioning the abort motor takes much less time.<\/p>\n
\u201cThe thermal conditioning for this motor isn\u2019t like a large motor where you have a big mass [and] it takes probably weeks to get under condition,\u201d Sara explained. \u201cThis motor needed four days.\u201d<\/p>\n
Similar to the large SLS boosters, the abort motor itself is started by a smaller, internal solid motor, an igniter. Within the LAS, the abort motor itself is upside-down, with the igniter firing from bottom to top. The exit gasses are directed through a turn-flow manifold to four nozzles at the top of the abort motor.<\/p>\n
\u201cThe purpose of this is to allow the gasses to come from the motor up through the center and then make a turn and go the opposite way, so it becomes a tractor motor, pulling the vehicle away,\u201d Sara explained.<\/p>\n
Other test objectives included verifying the performance of the joints where the motor attaches to the turn-flow manifold and where the four nozzles attach to the manifold.<\/p>\n
Configuration and preparations:<\/p>\n
Manufacturing and assembly of the abort motors is done at Orbital ATK\u2019s Propulsion Systems Utah facilities.<\/p>\n
The composite case of the motor is manufactured in their Refurbishment\/Aerospace Structures facility in Clearfield, Utah, facility. The nozzles and other smaller components are manufactured at the Promontory facility. Final assembly of all the components is done at the Headquarters\/Bacchus facility in Magna, Utah.<\/p>\n
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The fully assembled motor arrived at the T-93 facility in April to begin the final part of the test campaign.<\/p>\n
\u201cAs far as the test itself, we get all things ready ahead of time that we can in terms of tools, materials, and instrumentation and then we get [the motor] to the test area,\u201d Sara said. \u201cActually, [it was] a little bit late because of weather delays. It was supposed to arrive at the test facility and be in the test stand on the first of April, but had a delay of almost two weeks.\u201d<\/p>\n
Another significant objective of the QM-1 test was to better characterize the acoustics that firing the abort motor produces on Orion.<\/p>\n
The configuration at the T-93 facility for this test included a more elaborate set up to collect acoustic data than the previous full-scale test conducted there in 2008, which had a single near-field plume acoustic (NFPA) array positioned on the perimeter of the motor.<\/p>\n
\u201cWhen we did this back in 2008 we had one of these arrays, that had acoustic gauges on it to gather information,\u201d Sara explained. \u201cIt was felt since that time from the entire community that there was a desire to have more information on acoustics.\u201d<\/p>\n
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In addition to a second NFPA array around the motor, a heat-shield array with additional acoustic sensors was hung over it.<\/p>\n
\u201cIt\u2019s called the heat shield array \u2014 it\u2019s essentially the same distance [from the abort motor] as the heat shield for the crew module. What\u2019s also unique about it is we usually don\u2019t hang things over or near our motor when we go fire. So it was an interesting challenge to figure out how we\u2019re going to do this. It was desired not to build a structure because the structure would be in the way of acoustics reflection.\u201d<\/p>\n
Dr. McNamara said that the additional acoustic data collected from this test should allow refining of loads analysis.<\/p>\n
\u201cThe acoustics translates into loads. Originally from the ST-1 firing that we did out here, the acoustic levels were higher than we thought and so we had to go back and come up with the ogives on the outside of the LAS,\u201d he explained.<\/p>\n
\u201cAnd those ogives require a hatch on them and then the components inside with all the higher [acoustic] levels cause the qualification of all the other components on the crew module and the service module all to be tested and qualified at a higher level. The acoustics information we get back [and the] reduced thrust here, we\u2019ll be able to apply that to the loads and drop the loads down across the vehicle, across the spacecraft.\u201d<\/p>\n
LAS overview:<\/p>\n
The abort motor is one of three primary solid rocket motors in the overall Orion LAS; together with the crew module, the LAS elements make up a launch abort vehicle.<\/p>\n
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If activated in an abort, the abort motor pulls the full abort vehicle away from the launch vehicle while the attitude control motor assists with controlling the initial separation. The abort motor.<\/p>\n
The ACM then reorients the vehicle for separation events and for the crew module parachute deployment sequence. The LAS is then separated from the crew module with the jettison motor.<\/p>\n
Other elements of the LAS include a fairing assembly that covers the crew module and a Motor Adaptor Truss Assembly (MATA) that structurally connects the LAS with the CM.<\/p>\n
The LAS can be used for aborts while the spacecraft is still on the pad and during launch up to altitudes of 300,000 feet. During a nominal SLS crew launch, the jettison motor will fire to separate the LAS from the CM and the rest of the launch vehicle about three and a half minutes after liftoff.<\/p>\n
Development of the LAS began during Orion\u2019s days within the Constellation program of the past decade. The QM-1 test is the third full-scale test-firing of an abort motor.<\/p>\n
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The first was the ST-1 static test that was conducted in the same T-93 test facility in November, 2008. The second was as a part of the PA-1 pad abort test in New Mexico at the White Sands Missile Range in May, 2010.<\/p>\n
\u201cWe kept the attitude control motor the same. So working down the stack, attitude control motor is on top \u2014 we kept that the same,\u201d Dr. McNamara noted about some of the changes to the LAS since Constellation.<\/p>\n
\u201cThen [with] the jettison motors, we have made some changes to it after we did demonstration motor firings and after we did Pad Abort-1. We did a remix on the propellant to stabilize it a little bit more, and then on this abort motor is where we really backed down on the thrust on it.\u201d<\/p>\n
He also noted that the MATA design changed from composite to metallic, which will reduce its mass and increase its strength.<\/p>\n
Data reviews and modal testing:<\/p>\n
Sara said that the initial data \u201cquick look\u201d would be available just a couple of hours after the test was conducted.<\/p>\n
\u201cWe have a lot of data lines that we\u2019re going to be analyzing and reviewing,\u201d he said. \u201cWe can do some of it immediately \u2014 we\u2019re going to have a test review later this afternoon to review much of that data and that\u2019s mostly ballistic data for the performance of the motor, thrust and time and that kind of thing.<\/p>\n
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\u201cBut there\u2019s a lot of data that we\u2019re going to analyze, the strain gauges and so forth.\u201d<\/p>\n
In a press release posted after the quick look review, Orbital ATK noted \u201cmore analysis will be performed in the coming weeks, but all initial test results appear to be nominal.\u201d The Orbital ATK press release also noted that the quick look confirmed that the motor reached 400,000 pounds of thrust in the expected one eighth of a second.<\/p>\n
Rather than immediately begin disassembly of the motor, Sara said it will stay in the stand for modal testing first.<\/p>\n
\u201cIt will have to sit in that stand for a couple of weeks. The reason for that is we\u2019re going to do what we call a modal survey where we ping the motor and get vibration back to get the frequency of the motor and also multiple frequencies of the motor to get that kind of information,\u201d he explained.<\/p>\n
\u201cSo we can\u2019t really take anything apart until we do that test. Once that\u2019s done, then we take it apart, take all the parts apart, look at the joints. We also cut up some of the pieces as well, to look how they performed against what we expected them to do.\u201d<\/p>\n
Future test sequence:<\/p>\n
Two additional qualification tests of the abort motor are planned at Promontory to verify that the design is ready to fly on Orion with a crew on-board EM-2.<\/p>\n
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\u201cSo this motor test is QM-1. We have QM-2 and QM-3 that we need to test,\u201d Dr. McNamara added. \u201cWe\u2019ll do all three qualification motor firings before EM-2, when we put crew on [Orion]. If we were going to have to put crew on EM-1, we were going to have to accelerate those firings.<\/p>\n
\u201cQM-2 and QM-3 should be an exact duplicate of this motor, so we feel we\u2019ve got everything into this that we plan on doing to it and then almost like you\u2019re in production we\u2019ll do two [further tests] and then we\u2019ll say it\u2019s repeatable from QM-1 to QM-2 to QM-3.\u201d<\/p>\n
In parallel with the abort motor tests, the attitude control and jettison motors are also going through their qualification tests.<\/p>\n
\u201cAs far as the attitude control motor, we\u2019ve got some other tests going on there but same thing \u2014 QM-1, QM-2, and QM-3 with those,\u201d Dr. McNamara explained. \u201cAnd then on the jettison motor, same thing \u2014 three qualification motor firings there.\u201d<\/p>\n
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The goal is to have the final design of all the LAS elements in place for the Ascent Abort-2 (AA-2) integrated LAS test, which will launch the full launch abort vehicle on top of a modified Peacekeeper missile up to simulated maximum dynamic pressure conditions where an abort sequence will be triggered.<\/p>\n
Although it was decided not to put crew on the EM-1 flight, the feasibility assessment showed that the AA-2 test date could still be accelerated.<\/p>\n
Dr. McNamara said it could be moved up into the second quarter of 2019 from the current December, 2019, target.<\/p>\n
\u201cWe\u2019re on track to accelerate that, we\u2019re working out all of the schedules, the funding, the personnel, where everything is located and can we actually get there,\u201d he said.<\/p>\n
\u201cWe\u2019re detailing that out right now.\u201d<\/p>\n
(Images: Orbital ATK, NASA and L2 via Philip Sloss for NASASpaceFlight.com and L2 artist Nathan Koga \u2013 The full gallery of Nathan\u2019s (SpaceX Dragon to MCT, SLS, Commercial Crew and more) L2 images can be *found here*))<\/p>\n
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Following Orbital ATK successful test-firing of an Orion launch abort system (LAS) abort motor at their Promontory facility in Utah on June 15, two more qualification tests will be required before the vital crew safety element is officially ready to fly with crewed Space Launch System (SLS) missions, beginning with Exploration Mission -2 (EM-2) mission […]<\/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":[4011,8473,624],"class_list":["post-38782","post","type-post","status-publish","format-standard","hentry","category-news","tag-em-2","tag-las","tag-sls"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/38782"}],"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=38782"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/38782\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=38782"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=38782"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=38782"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}