- \n
- Orion Forum Section<\/li>\n
- L2 Orion Section<\/li>\n
- Click here to Join L2<\/li>\n<\/ul>\n
The AA-2 team at JSC is adding only the required test equipment inside and outside the simulator to command the dynamic parts of the test, while simultaneously collecting all of the desired test data and transmitting and recording it.<\/p>\n
\u201cThere\u2019s not a whole lot in there right now,\u201d Jennifer Devolites, AA-2 crew module deputy manager for NASA, said. \u201cWe don\u2019t have crew systems, we don\u2019t have life support systems, but we have all the avionics and power, all the wiring and harnessing that has to be installed, all the instrumentation.\u201d<\/p>\n
\u201cYou can see some blue tape on the outside, those are protections where we have pressure sensors installed,\u201d she added. \u201cWe\u2019ve only done about half of the sensors that need to go on the vehicle, all that gets installed.\u201d<\/p>\n
Spaceflight history books
<\/path>Technology News <\/path>Astronomy <\/path>\n (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n
To save money it was decided to use a crew module simulator for this test rather than launch a more flight-like crew module, such as the one that flew on Exploration Flight Test-1 (EFT-1). The LAS itself, which is fully active and fully exercised in the test, is a production unit. \u201cThe separation mechanisms, all of that is production [equipment],\u201d Devolites also noted.<\/p>\n
As with the simulator, the test avionics are not flight units. \u201cBasically all the powered systems inside are different from the mainline Orion,\u201d Devolites explained. \u201cWe were able to use a lot of commercial, off-the-shelf [systems since] we\u2019re not going to space. And so we were able save a lot of money by using mostly off-the-shelf components for a lot of that equipment rather than going with spaceflight-qualified systems that are used on the mainline Orion.\u201d<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2018\/04\/P1090615.35pct.jpg\")
<\/p>\nCrew module simulator for AA-2 test at JSC, April 26. The blue tape covers pressure sensors installed for the test. Credit: Philip Sloss for NSF\/L2.<\/p>\n
\u201cThe only piece of the software that\u2019s the same is the guidance, navigation, and control (GNC) for the LAS,\u201d she continued. \u201cWe wanted that to be the same, because that re-orientation is a critical part of the flight test. So we take that and then we\u2019ve got it embedded in a different software environment.\u201d<\/p>\n
\u201cThe LAS has the computers to control the abort motor and the attitude control motor firings, but we send the commands, and so we actually send the steering commands to the LAS from our vehicle,\u201d she noted.<\/p>\n
After all the test equipment has been installed and connected, they\u2019ll make it sure it\u2019s working. \u201cWe do powered-on testing, and we\u2019ll actually do closed-loop, hardware-in-the-loop testing out here,\u201d Devolites said. \u201cWe have one of the LAS attitude control motor controllers here from Lockheed Martin that we use in our testing, so we can go all the way closed loop with it. So we\u2019ll do testing here, we\u2019ll do mission simulations.\u201d<\/p>\n
Lockheed Martin is the prime contractor for Orion.<\/p>\n
After the instrumentation and avionics are installed and tested, Devolites said they will measure the mass properties of the simulator, such as weight and center of gravity (cg), again. \u201cIt\u2019s our X-cg fixture,\u201d she noted. \u201cWe\u2026put the vehicle on it [and] rotate it over 90 degrees to get the X-cg, it\u2019s going to be very exciting.\u201d The simulator will mimic the production Orion\u2019s mass and center of gravity.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2018\/04\/lrc-2018-h1_p_orion-021608.50pct.jpg\")
<\/p>\nCrew module simulator in the X-cg fixture at Langley, February 2018. The simulator will be put in the fixture again after it is outfitted at JSC to re-measure its mass properties. Credit: NASA\/David C. Bowman<\/p>\n
The fully outfitted crew module simulator will then be transported from JSC to the Plum Brook Station facility near the Glenn Research Center in Cleveland, Ohio. \u201cWe\u2019re doing acoustic characterization at Plum Brook, but it\u2019s really from the model perspective, right?\u201d Devolites said. \u201cSo they can characterize the acoustic environment before we fly \u2014 that way they can match it to the actual flight results and compare their models. That\u2019s really for anchoring the models.\u201d<\/p>\n
While the crew module simulator is at Plum Brook, Devolites noted that the JSC team will receive the separation ring from Langley and outfit that for the test before the crew module simulator returns to Houston to be mated to the ring. \u201cSo we\u2019ll do that here, integrate them together, and ship it all to the Cape, hopefully by December,\u201d she said. The separation ring sits between the crew module and booster to quickly disconnect them when the abort is initiated.<\/p>\n
Once at the launch site, the vehicle elements will be connected for integrated systems testing. \u201cWe\u2019ll do testing with the LAS before it gets stacked,\u201d Devolites explained. \u201cWe do what\u2019s called soft-mate testing. We\u2019ll electrically connect it [and] check out all the interfaces between the systems. We also do soft-mate testing with the booster \u2014 electrically make sure everything works.\u201d<\/p>\n
\u201cWe just keep doing incremental, integrated tests up until launch,\u201d she added. The test is scheduled for April, 2019.<\/p>\n
AA-2 Overview<\/p>\n
The AA-2 test is the second and last planned abort test for Orion. The first test was Pad Abort-1 (PA-1) in 2010, which tested an early version of the LAS in an abort starting at rest on the ground. At the time, Orion was still a part of a Constellation program that was being shut down ahead of proposed cancellation; the plans in Constellation included a longer test series.<\/p>\n
After the Orion program was rescoped following its cancellation along with all of Constellation, the AA-2 test was the only in-flight \u201cascent abort\u201d test brought forward and the program had to pick a single abort condition to test.<\/p>\n
\u201cIn the Constellation program we did have more in-flight abort tests planned and what we did was we picked apart that in-flight profile more,\u201d NASA Orion Program Manager Mark Kirasich said. \u201cI\u2019ll give you a \u2018for example.\u2019 When you abort at a very high altitude there\u2019s less atmosphere, so there\u2019s not as much aerodynamic force on the vehicle. So you have to control your attitude differently, [in that example] it\u2019s more of a reaction control system thruster test as opposed to where we\u2019re right in the thick of the atmosphere it\u2019s really the [LAS] attitude control motor that we\u2019re testing, the dynamics in that.\u201d<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2018\/04\/vlcsnap-2096-06-16-21h52m52s583.png\")
<\/p>\nImage from a video of an Orion abort simulation produced by the NASA Advanced Supercomputing (NAS) Division at Ames Research Center. Colored plumes indicate high pressure (red) and low pressure (blue). Credit: NASA\/Ames\/Timothy Sandstrom<\/p>\n
\u201cSo we spread the test points around and\u2026right now the point that we\u2019re doing on AA-2 is the combination where we get\u2026kind of a smorgasbord of the most-challenging conditions,\u201d he explained. \u201cPerhaps not the hundredth-percentile of every one of the five or six key parameters but 98 percent at most of them. And that\u2019s why we picked the test conditions that we did.\u201d<\/p>\n
Kirasich noted that the abort condition for this test will stress the ability of the LAS to maintain control of the aborting vehicle more than the ability of the LAS to get away from the booster. \u201cThe harder part is to control, because the aerodynamics are pushing you all over the place under those circumstances,\u201d he explained.<\/p>\n
The data collected in the test will help to validate existing computer models, which will be used to simulate test cases throughout an envelope of possible abort conditions.<\/p>\n
The test will launch from Launch Complex 46 (LC-46) at the Cape Canaveral Air Force Station (CCAFS) in Florida. An Orbital ATK SR 118 rocket motor is the booster for the test. Its original purpose was as the first stage of the Peacekeeper Inter-Continental Ballistic Missile (ICBM). The Peacekeeper program was deactivated in 2002 and today the motors in the inventory are used for commercial purposes such as space launches.<\/p>\n
The abort will be triggered when the vehicle is traveling at approximately Mach 1.3 at an altitude of around 31,000 feet. After liftoff, the booster takes the vehicle up to the abort condition and then signals the crew module.<\/p>\n
\u201cThe booster is responsible for getting us to the abort condition and then based on the signal to us to say \u201cwe\u2019re here,\u201d we execute the abort and perform the rest of the flight after that,\u201d Devolites explained. \u201cIt\u2019s over Mach 1, and it\u2019s a high dynamic pressure, and it\u2019s a combination of angle of attack and a couple of other parameters.\u201d<\/p>\n
The LAS has three different motors that fire at different points in the test: the abort motor and the attitude control motor (ACM) are built by Orbital ATK and would only be used in an abort case, and the jettison motor. Aerojet Rocketdyne makes the jettison motor, which is used on every mission to separate the LAS from Orion.<\/p>\n
The Orion crew module and the LAS elements make up the launch abort vehicle (LAV) that separates from the test booster in flight. The three motors make up the launch abort tower; 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
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2018\/04\/AA-2-Composite-Copy.jpg\")
<\/p>\nDiagram of AA-2 test vehicle, left. Diagram of Orion LAS, right. Credit: NASA<\/p>\n
When the abort is initiated, the abort motor instantly generates about 400,000 pounds of thrust at ignition, putting loads on the abort vehicle of twelve to thirteen g\u2019s to get away from the booster, while the ACM also fires to steer the vehicle away and put it in a good attitude. The abort motor fires for about five seconds with the thrust tailing off quickly while the ACM maintains control of the vehicle.<\/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
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
During the AA-2 test, the crew module is collecting all of the data from the sensors inside and outside. \u201cPrimarily it\u2019s a lot of pressure sensors, a lot of accelerometers, a lot of thermocouples to measure that whole aerothermal environment,\u201d Devolites noted. \u201cThere\u2019s of course all the on-board flight instrumentation for the systems \u2014 we get all of that data telemetered down.\u201d<\/p>\n
The data is being transmitted from the crew module for local ground stations to receive and record. \u201cWe have no uplink or command capability,\u201d she said. \u201cWe would like to watch the whole thing as it happens during flight but we really just need to get all the data down.\u201d<\/p>\n
Devolites said they are looking at using four ground stations for the test: \u201cA couple of them will be able to give us real-time data and a couple of them are going to be just recording the data that we can retrieve later.\u201d<\/p>\n
For redundancy, the crew module is also recording all the data on-board. \u201cWe think we\u2019ll have comm all the way down and get the telemetry, but just in case we\u2019ve got the backup data recorders,\u201d she added.<\/p>\n
\u201cAt the point at which the LAS jettisons, you\u2019ve got a plume and even during abort you\u2019ve got a plume,\u201d she said. \u201cWe think that\u2019s not going to be a problem [for telemetry]. You also have an orientation at various points in time away from the ground tracking stations, and so for full coverage, that\u2019s why we\u2019ve also got ejectable data recorders.\u201d<\/p>\n
The crew module will impact the water without being slowed down and is expected to sink, so the AA-2 team is using another off-the-shelf system in order to recover the recorders.<\/p>\n
![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2018\/04\/vlcsnap-8169-12-11-16h20m38s184.png\")
<\/p>\nImage from NASA animation of the AA-2 test showing ejection of one pair of the twelve data recorders on the vehicle. Credit: NASA<\/p>\n
\u201cThe deployment system we\u2019re using is ALE-47, which is a military\/Air Force chaff deployment system,\u201d Devolites explained. \u201cIt\u2019s an ejection system for fighter aircraft for the chaff or the flares and so we said that\u2019s perfect, we just need an ejection capability to get the data recorders out. We\u2019re using that system and [the recorders] are just built very robust, so they can just eject and drop in the water and then survive.\u201d<\/p>\n
There are twelve recorders grouped in two sets of six located at the top of the crew module simulator on opposite sides under the simulated forward bay cover. After the jettison motor fires to pull the LAS away from the crew module, the simulator will free fall to the water.<\/p>\n
\u201cThe recorders start getting ejected about twenty seconds after LAS has jettisoned,\u201d she noted. \u201cWe wanted to continue collecting data during free fall and not just immediately start ejecting. They eject in pairs and we eject every ten seconds so that way we get more and more data as we get down.\u201d<\/p>\n
The recorders are designed to float and they have beacons to expedite locating them for recovery. \u201cWe only need one to give us everything up through twenty seconds after LAS jettison, but we keep ejecting basically as long as we can,\u201d she added. \u201cThose are redundant as well so you get a pair \u2014 one from each side on each ejection.\u201d<\/p>\n
From liftoff to water impact, the test is expected to last less than three minutes.<\/p>\n","protected":false},"excerpt":{"rendered":"
NASA is getting the hardware ready for an important test next year of the launch abort system (LAS) that Orion spacecraft will use during launch on missions to the Moon in the 2020s. At the Johnson Space Center (JSC) in Houston, Texas, a crew module simulator is being outfitted with equipment to turn it into […]<\/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":[8940,640,624],"class_list":["post-38460","post","type-post","status-publish","format-standard","hentry","category-news","tag-aa-2","tag-orion","tag-sls"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/38460"}],"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=38460"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/38460\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=38460"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=38460"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=38460"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}