{"id":12401,"date":"2020-06-22T21:29:25","date_gmt":"2020-06-22T13:29:25","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/sls-booster-segments-arrive-in-florida-but-stacking-on-hold-until-core-stage-test\/"},"modified":"2020-06-22T21:29:25","modified_gmt":"2020-06-22T13:29:25","slug":"sls-booster-segments-arrive-in-florida-but-stacking-on-hold-until-core-stage-test","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/sls-booster-segments-arrive-in-florida-but-stacking-on-hold-until-core-stage-test\/","title":{"rendered":"SLS booster segments arrive in Florida, but stacking on hold until core stage test"},"content":{"rendered":"
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The 10 booster segments for the first flight of NASA\u2019s Space Launch System travel across a bridge between Titusville, Florida, and the Kennedy Space Center on Monday, June 15. Credit: Northrop Grumman<\/figcaption><\/figure>\n

Fueled segments of the solid rocket boosters that will lift off on the first flight of NASA\u2019s Space Launch System have arrived at the Kennedy Space Center in Florida, but officials will hold off on stacking the boosters until the SLS core stage completes a crucial test-firing later this year.<\/p>\n

Loaded in 10 specially-designed railcars, the 10 segments that will make up the first Space Launch System\u2019s twin solid rocket boosters rolled into the Kennedy Space Center on June 15 after a railroad journey from a Northrop Grumman facility in northern Utah, where the rocket sections were filled with solid propellants.<\/p>\n

Teams at Northrop Grumman\u2019s solid rocket booster facility in Utah completed the process of casting aluminum powder fuel, ammonium perchlorate oxidizer, and binding agent into all 10 segments of the first flight-ready SLS boosters in 2017, then put the cylinders into storage to await shipment to the Kennedy Space Center when NASA needed to receive the sections for stacking.<\/p>\n

The SLS boosters will be stacked on NASA\u2019s mobile launcher, a towering structure and platform currently undergoing final testing and checkouts inside the Vehicle Assembly Building at Kennedy. Once the boosters are in place, the SLS core stage will be positioned in between the boosters, followed by raising of the SLS upper stage and the Orion crew capsule, which will fly without astronauts on the first SLS test flight.<\/p>\n

The SLS will send the unpiloted Orion spacecraft \u2014 comprised of a pressurized Lockheed Martin-made crew cabin and a European-built service module \u2014 toward lunar orbit for a demonstration mission planned to last several weeks. The Orion will come back to Earth for a parachute-assisted splashdown in the Pacific Ocean.<\/p>\n

Future SLS\/Orion missions will carry crews to the moon for NASA\u2019s Artemis program, which aims to land astronauts on the moon\u2019s south pole by the end of 2024.<\/p>\n

Liftoff of the first SLS\/Orion test flight, designated Artemis 1, is scheduled for November 2021, four years later than planned when the SLS program was unveiled in 2011.<\/p>\n

\u201cWe\u2019ve been working long and hard here to prepare the center for processing of the Space Launch System and Orion, and the fact that we\u2019re upon that right now with the booster work that we\u2019re doing is very exciting,\u201d said Jeff Angermeier, NASA flow director for the Artemis program at the Kennedy Space Center.<\/p>\n

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This illustration shows the components of the Space Launch System\u2019s Block 1 configuration, which is the version scheduled to fly on the rocket\u2019s first mission, designated Artemis 1. Credit: NASA<\/figcaption><\/figure>\n

The boosters for the Space Launch System are derived from the solid rocket motors that flew on the space shuttle. The main difference is the addition of a fifth segment in the center of the booster, which gives the solid rocket motor extra fuel capacity.<\/p>\n

The SLS boosters will each generate 3.6 million pounds of thrust at peak power, while each four-segment booster on the space shuttle produced a maximum of 3.3 million pounds of thrust. Built to fire for about 2 minutes, 6 seconds, the solid rocket boosters will provide about 75 percent of the total thrust to propel the Space Launch System off the ground.<\/p>\n

\u201cWe\u2019re very comfortable working with those motors having accomplished 135 flights with shuttle,\u201d Angermeier said. \u201cThe big difference with this one, and one of the exciting things about the booster for Artemis, is that they\u2019re a five-segment motor versus the four-segment motor we had for shuttle.<\/p>\n

\u201cSo we have a couple of more segments we have to process, and that will give us a little bit more thrust, a little bit more horsepower, getting off the ground here when we have the launch in 2021,\u201d he said.<\/p>\n

But the boosters on the Space Launch System won\u2019t be recovered and reused like they were during the space shuttle program. The SLS core stage\u2019s four reusable RS-25 main engines are also leftovers from the shuttle program, but they will be expended with the core stage on each launch.<\/p>\n

In an interview with Spaceflight Now, Angermeier said the aft segment of each booster will be the first motor sections to be inspected and prepared for stacking. Those two segments will go into the Rotation, Processing and Surge Facility north of the Vehicle Assembly Building to be unloaded from their railcars, followed the other eight booster segments.<\/p>\n

Engineers will inspect the propellant grains and attach joints on each 180-ton solid motor segment, and install sensors that will be used during pre-launch testing of the fully-assembled Space Launch System vehicle, according to Angermeier.<\/p>\n

Crews inside the RPSF will also paint the NASA \u201cworm\u201d logo on some of the motor segments, continuing the reemergence of the 1970s-era logotype began with the red worm\u2019s appearance on the SpaceX Falcon 9 rocket that launched astronauts Doug Hurley and Bob Behnken into orbit May 30.<\/p>\n

\u201cWe\u2019re going to paint on what we call the NASA worm,\u201d Angermeier said. We\u2019ll paint that onto the boosters.\u201d<\/p>\n

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Elements of the SLS solid rocket boosters for the Artemis 1 mission previously flew on 40 space shuttle flights. Credit: Northrop Grumman<\/figcaption><\/figure>\n

On the aft motor segments, ground teams will attach the aft skirts, which contain the thrust vector control system to help steer the launch vehicle in flight.<\/p>\n

\u201cWe mate to the aft skirt, and we do a lot of the work to prepare that aft motor assembly for stacking,\u201d Angermeier said. \u201cThere\u2019s a core stage attach ring and the struts that we install. We install the aft exit cone onto the aft motor, do the thermal curtain installs, and there\u2019s DFI (Developmental Flight Instrumentation) that we also need to install. So a handful of ops that we do special to the aft motor segments, and once that\u2019s done we call it the aft booster assembly.<\/p>\n

\u201cWe do that work, and it extends over about a month period of time for each one of the motors,\u201d he said. \u201cOnce we\u2019re done with those operations, then whenever we need the aft (assemblies) over in the VAB, we\u2019ll put them on a transportation pallet and move it over to the VAB.\u201d<\/p>\n

Booster stacking will wait for key SLS core stage test<\/strong><\/em><\/p>\n

Angermeier said the booster segments should all be ready for stacking by the end of September, but ground teams at Kennedy will wait to begin building up the boosters on the mobile launcher until the SLS core stage completes a test-firing of its four hydrogen-fueled main engines on a test stand at the Stennis Space Center in Mississippi.<\/p>\n

The eight-minute test-firing was planned to occur in August, but has been delayed to later this fall due to work interruptions caused by the coronavirus pandemic. The core stage will be transported from Mississippi to the Kennedy Space Center on NASA\u2019s Pegasus barge once the test-firing, known as a green run hotfire, is completed.<\/p>\n

The earliest the core stage might be delivered to the Florida launch site is November, but that schedule could be delayed further if teams encounter problems with the rocket, or work on the core stage slows due to the coronavirus pandemic or poor weather.<\/p>\n

\u201cWe\u2019re waiting until the hotfire (to begin stacking the boosters),\u201d Angermeier said. \u201cThe reason being is we have limited life items, time-based requirements, for multiple items on the vehicle. On the boosters, a limited life item is from the time we mate the first joint we have a limit life that says you should launch that booster within 12 months.<\/p>\n

\u201cSo right now, by linking up with the core stage (schedule), that pretty much assures us that we\u2019ll be able to stack the boosters and get it off the ground before those 12 months expire \u2026 So anywhere between two to four weeks after hotfire is when we would start our booster stacking,\u201d Angermeier said.<\/p>\n