Behind the Scenes at QM-2: Getting Ready to Test the World’s Largest Solid Rocket Motor

By Beverly Perry

For two monumental minutes on June 28, the Space Launch System (SLS) solid rocket boosters — the largest ever built for flight — will fire up in an amazing display of power as engineers verify their designs in the last full-scale test before SLS’s first flight in late 2018. Each piece of hardware that’s qualified and each major test — like this one, dubbed QM-2 — puts NASA one step closer on its Journey to Mars.

The smoke and fire may last only two minutes, but engineers at NASA’s Marshall Space Flight Center in Huntsville, Alabama and Orbital ATK in Promontory, Utah have been preparing weeks — even months — in advance for the static test of Qualification Motor 2 (QM-2). Here’s a behind-the-scenes look at what goes into getting ready to fire up the largest and most powerful solid rocket motor ever built for flight.

T (for test) minus weeks and months. In the months prior to the test, propellant-filled segments began arriving at Orbital ATK’s Test Bay T-97 after being cast in nearby facilities. Many of these segments are veterans of space shuttle flights. In fact, the various metal case segments that comprise the five-segment QM-2 motor flew on 48 shuttle flights!

T minus 14 days. In the two weeks leading up to the test, Orbital ATK engineers begin dry runs that simulate the final test as closely as possible (without the smoke and fire). They put the motor and associated systems through their paces no fewer than 11 times before the big day to ensure not only that all systems are functioning as expected, but also that the test will be executed properly. “We only get one shot at firing the rocket motor,” says Dr. Janica Cheney, Orbital ATK’s director of Test Operations. “All the dry runs and other preparations that take place ahead of time are critical to ensuring we get the data we need from this test firing.”

NASA and Orbital ATK test SLS Qualification Motor-2 (QM-2) before first flight.
Are you ready? It’s time for the final full-scale test before the first flight test of the SLS solid rocket motor June 28 at 10:05 a.m. EDT (8:05 a.m. MDT). Many cameras record data during the test, such as this one which captures nozzle plug performance during the test.

T minus 24 hours. For this final full-scale static test, engineers have 82 goals, or test objectives, they need to measure and evaluate. One day before the test, it’s crunch time; caffeine’s flowing as engineers work around the clock the day before the test to ensure all systems function properly and all necessary data can be collected.

T minus 8 hours. Game day. There’s focus — and excitement. There are two more dry runs leading up to the test. Engineers, technicians and operators are “on station,” — present and accounted for at key locations such as the test bay, the instrument rooms and the control bunker. When you hear “control bunker,” think mission control — a command and control center that directs every aspect of the test, similar to what you see at mission control during a launch. Time flies during the final eight hours before the test.

Orbital ATK’s Test Bay housing rolls back to reveal Qualification Motor-2 (QM-2).
At T minus 6 hours with a “go” decision for testing QM-2, engineers at Orbital ATK will roll back the booster test bay housing so the massive motor can be fired.

T minus 6 hours. At 4:05 a.m. EDT (2:05 a.m. MDT), engineers and managers at Orbital ATK and NASA will make a “go” or “no go” decision on testing that day. Assuming the test’s a go, technicians “roll back” Orbital ATK’s specially designed moveable test bay housing and begin running final checks to make sure everything is ready. “We check the status of all the data and control systems, the test bay, the motor preparation and weather conditions,” Cheney says.

Weather is one variable that can halt the QM-2 test. “We make sure there’s no lightning in the area; no high winds; no storms,” explains Orbital ATK Fire Chief Blair Westergard. “We also establish fire breaks. Along with the Box Elder County Fire District, we’re prepared to extinguish any secondary wildfires too.”

Engineers also make sure cameras are ready to film and all data recording systems are online and functioning properly. Orbital ATK Security ensures the area around the test is clear.

T minus 3 hours. Crowds begin to gather as the public viewing area near Promontory off State Route 83 opens at 7:30 a.m. EDT (5:30 a.m. MDT). Orbital ATK Security directs traffic with the help of the Utah Highway Patrol and provides crowd control support to ensure everything remains orderly — vital when 10,000 people are in attendance.

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T minus 1 hour. The formal countdown commences; the public address system broadcast begins. The crew in the test bay begins final procedures to prepare the booster for testing.

T minus 9 minutes. Final system and timing checks are underway.

T minus 4 minutes. A “go for test” announcement sounds from the public address system.

T minus 1 minute. A siren begins; it will blare through T minus 20 seconds.

T minus 45 seconds. The “Safe and Arm” system sequence begins, which arms the motor. The Safe and Arm device is remotely activated from the “safe” position into the “armed” position, allowing the motor to ignite when the “fire” command is given.

T minus zero. At 10:05 a.m. EDT (8:05 MDT), two minutes of pure awesome commence as the gigantic motor burns through about five and a half tons of propellant each second during the approximately two-minute test. Inside the control bunker, there will be jubilation — and relief. “This is serious business — this is rocket science,” Cheney emphasizes. “But there’s nothing better than the smoke and fire and the data that comes with it when you’ve had a successful day. Our success is NASA’s success — we don’t do it alone.”


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Three Cool Facts About QM-2

By Beverly Perry

The countdown to the last full-scale test firing of the massive Space Launch System (SLS) solid rocket boosters has begun. Mark your calendars: June 28, 8:05 a.m. MDT.

Expect two minutes of shock and awesome as the flight-like motor burns through about six tons of propellant each second during the test. With expanding gases and flames exiting the nozzle at speeds in excess of Mach 3 and temperatures reaching 3,700 degrees Fahrenheit, say goodbye to some of the sand at Orbital ATK’s test facility in the Utah desert because after the test, the sand at the aft, or rear, end of the booster motor will be glass.

NASA and Orbital ATK are rolling back the house and rocking the Utah desert for QM-2 June 28.
NASA and Orbital ATK are rolling back the house and rocking the Utah desert for QM-2 June 28.

The 154-foot long Qualification Motor 2 (QM-2) consists of the five propellant-filled segments in the middle of the booster; the aft skirt is also part of the test, but the forward assembly (nose cap, forward skirt) won’t be. (See our Boosters 101* infographic if you need a refresher on booster parts and assemblies). The test will broadcast live on NASA TV and our Facebook page. We will also live tweet from @NASA_SLS on Twitter.

For those watching at home (or work), here are three cool things that might not be so obvious on the screen, in countdown order.

3. This motor’s chill. QM-2’s been chilling — literally, down to 40 degrees — since the first week in May in Orbital ATK’s “test bay housing,” a special building on rails that moves to enclose the booster and rolls back so the motor can be test-fired. Even though SLS will launch from the normally balmy Kennedy Space Center in Florida, temperatures can vary there and engineers need to be sure the booster will perform as expected whether the propellant inside the motor is 40 degrees or 90 degrees (the temperature of the propellant during the first full-scale test, Qualification Motor 1 or QM-1).

2. This booster’s on lockdown. If you happen to be near Promontory, Utah on June 28, you can view the test for yourself in the public viewing area off State Route 83. And don’t worry, this booster’s not going anywhere — engineers have it locked down. The motor is held securely in place by Orbital ATK’s T-97 test stand.

During the test, the motor will push against a forward thrust block with more than three million pounds of force. Holding down the rocket motor is more than 13 million pounds of concrete — most of which is underground. The test stand contains a system of load cells that enable engineers to measure the thrust the motor produces and verify their predictions.

Solid rocket booster test burns so hot it turns sand to glass.
The solid rocket motor test firing will burn so hot the sand at the aft end of the motor will turn to glass.

Putting out the fire at the end of the test is the job of the quench system, which fills the motor with carbon dioxide from both ends of the test stand. A deluge system sprays water on the motor to keep the metal case from getting too hot so the hardware can be re-used. Both the quench and deluge systems had to be upgraded to handle the heat and size of the big five-segment boosters.

1. Next time, it’s for real. These solid rocket boosters are the largest and most powerful ever built for flight. They’ve been tested and retested in both full-scale and smaller subsystem-level tests. Engineers have upgraded and revamped vital parts like the nozzle, insulation and avionics control systems. They’ve analyzed loads and thrust, run models and simulations, and are nearing the end of verifying their designs will work as expected.

Most of this work was necessary because, plainly put, SLS needs bigger boosters. Bigger boosters mean bolder missions – like around the moon during the first integrated mission of SLS and Orion. So the next time we see these solid rocket motors fire, they will be propelling SLS off the launch pad at Kennedy Space Center and on its first flight with Orion. For real.

Next time: Behind the Scenes at QM-2: Getting Ready to Test the World’s Largest Solid Rocket Motor.


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Small Hitchhikers Ride through the Galaxy

By Beverly Perry

On the first launch of the Space Launch System (SLS), America’s next-generation heavy-lift rocket, the Orion Stage Adapter (OSA) will carry 13 CubeSats, or boot box-sized science and technology investigations, that will help pave the way for future human exploration in deep space. Engineers and technicians at NASA’s Marshall Space Flight Center have built the main structure of this hardware that will be part of the rocket when it lifts off from Launch Complex 39B at NASA’s modernized spaceport at Kennedy Space Center in Florida.

The Orion Stage Adapter being designed and manufactured at NASA’S Marshall Space Flight Center in Huntsville, Ala. nears completion.
Jennifer Takeshita, the lead for friction stir welding at Teledyne Brown Engineering, compares a model of the Orion Stage Adapter (OSA), including brackets to secure CubeSats during their spaceflight, to the flight hardware nearing completion at Marshall Space Flight Center.

The Orion Stage Adapter does exactly what its name indicates: it connects the Orion spacecraft to the second stage of the launch vehicle. Using enormous friction-stir welding machines, engineers just finished welding three large panels into a ring that is 18 feet in diameter and 5 feet high. With this welding complete, it’s time for analysis. The main structural ring is currently undergoing nondestructive analysis using 3-D structured light scanning and photogrammetry, which creates a computer model using photography, to ensure hardware was built to design specification.

Three-dimensional structured light scanning, photogrammetry, and solid modeling software are helping engineers visualize the minute differences between the OSA that was designed and the hardware that was built.
Engineers use 3-D structured light scanning and photogrammetry to analyze the main structure of the Orion Stage Adapter (OSA) at Marshall Space Flight Center. Targets for the optical scanner and SLR camera can be seen on the aluminum structure. Solid modeling software will combine the images into a single computer model so engineers can compare finished hardware to the design.

Next, engineers will trim it, weld upper and lower rings onto the large ring, machine it to final dimensions, apply paint, and install the diaphragm, a barrier that separates SLS from Orion. After that, installation of cables and the brackets that will secure the secondary payloads during their spaceflight will complete this critical piece of flight hardware.

The 13 CubeSat secondary payloads will be some of the first small satellites to explore deep space and answer critical questions relevant to NASA’s future exploration plans. These small but mighty scientific investigations include ten satellites from U.S. industry, government, and commercial partners as well as the three CubeSats being built by international partners.


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Next Generation Wants Its Mars Shot

By Beverly Perry

We don’t know who will take those first steps on Martian soil, ushering in the age of humans as a multi-planetary species. But we do already know a couple things about those first intrepid explorers: They’re taking steps on Earth right now; and they belong to a generation that is tech-savvy, and raised on the internet and social media. But do today’s students think about exploring beyond this world and into deep space?

University of Illinois Urbana-Champaign student rocketry team
Members of the University of Illinois Urbana-Champaign’s rocketry team said at NASA’s Student Launch competition that they look forward to NASA’s Journey to Mars and aspire to be a part of it.

“Every day – we can’t get enough of that stuff!” said Ben Collins from the University of Illinois Urbana-Champaign on a recent windy morning that was spent launching rockets in a field north of Huntsville. Collins and his teammates were among 51 student rocketry teams that competed in various challenges and sent their amateur rockets soaring during the 16th annual Student Launch rocketry challenge April 13-16.

Tuskegee University’s rocketry team at NASA’s Student Launch competition
Members of Tuskegee University’s rocketry team enjoy their day at NASA Marshall’s Student Launch.

At this year’s Student Launch, middle and high school students and university computer scientists, physicists and engineers of all stripes (aerospace and mechanical were particularly well-represented) got to tour NASA’s Marshall Space Flight Center, the center responsible for developing the Space Launch System (SLS), the country’s next-generation heavy-lift launch vehicle.

While there, the students heard from a member of their generation actively involved in designing and engineering SLS: Marshall engineer Kathryn Crowe, who is part of a generations-spanning workforce blending fresh thinking with years of experience. (See Time Flies: Next-Generation Rocket is the Work of Generations for more about Kathryn’s work.)

For some, the competition – and the visit – were a taste of things to come.

“My biggest career goal is to work on the Journey to Mars – to somehow be a part of it,” said Brandon Murchinson, also of the University of Illinois Urbana-Champaign. “I think SLS is incredible. As someone who’s always been interested in space exploration and travel, it’s why I chose this career path.”

NASA’s call for new astronauts earlier this year also made an impact on the future engineers and scientists at the Student Launch. Paul Grutzmacher, a 17-year-old senior at St. Vincent-St. Mary High School in Akron, Ohio, said that his career goal is to become a pilot for the Orion crew vehicle that will launch on SLS. “SLS excites me because it’s supposed to take us farther than we’ve gone before and it’s also our next heavy lifter,” he added.

St. Vincent-St. Mary High School rover at 2016 Student Launch.
St. Vincent-St. Mary High School’s Project Manager Raykwon Wookdruff describes the team’s rover, which autonomously located the team’s downed rocket, providing a proof of concept that an autonomous rover on Mars could locate and retrieve a supply rocket without astronauts having to leave the vicinity of their habitat.

Grutzmacher thinks he’s got the right stuff to fly on SLS, but so does Vanderbilt University’s Rebecca Riley, a senior computer science major who plans to continue her education in particle physics. “I think we’re all pretty excited that we might be the right age to be going to Mars. I’m like, Man, that’s going to be me going to Mars!”

These students recognize the value in missions that build expertise in long-duration spaceflight – and the technological spinoffs that arise from the process. To hear them tell it, long timelines just don’t scare them.

Auburn University’s student rocketry team tracks progress on America’s next great rocket by following social media and events like solid rocket booster static test firings and RS-25 main engine tests. “Social media makes it a lot more tangible,” said Auburn’s Burak Adanur. “And I think it gives people something to look forward to,” he said.

Vanderbilt University’s Andrew Voss has participated in the Student Launch over the past four years. “I have seen a lot of work go down,” he said. “And I like seeing the test stands because the work that goes into testing is a feat of engineering.” Check out our recent blog post on Engine 2059 for more about how an engine helped test a test stand.

Tech-obsessed students have no trouble spouting off advancements that have arisen from America’s space program: cell phone cameras, scratch-resistant sunglasses, memory foam, and the list goes on. Vanderbilt’s Voss said, “That’s part of what NASA’s always done, and what could come out of SLS is not just spaceflight, but technology that drives the world forward.”

Vanderbilt University rocketry team launches rocket
Members of Vanderbilt University’s student rocketry team spoke about the future of deep space exploration after successfully launching their rocket.

“I think that’s one of the most important aspects to space exploration,” said Auburn’s Adanur. “We have to go space because it’s a mechanism – it’s a crucible – that will change us as a society and give us new technologies. I think it has more of a ripple effect than most people think.”

Chris Lorenz of the University of Illinois at Urbana-Champaign said he sees the value of NASA’s proving ground missions to build up for human Mars landings. “I’m a big fan of what NASA does in robotic exploration. It’s smart to go unmanned and build up infrastructure first before attempting manned missions,” he said.

Vanderbilt’s Mitch Masia said that while proving ground missions are necessary, deep space exploration really gets people going. “The space station is awesome and a huge feat and deep space missions will get people even more excited.” Case in point: Worldwide amazement and wonder at the photos of Pluto NASA’s New Horizons spacecraft has been sending back to Earth.

Sylvania Northview High School rocketry team at NASA’s Student Launch competition
Members of Sylvania Northview High School’s rocketry team explain their project to other students during the Rocket Fair at NASA’s Marshall Space Flight Center the day before launch.

Participants at the Student Launch emphasized that their generation wants its chance to make history. They want their Mars shot. “I think SLS will bring our generation together,” said Michael D’Onofrio, a 17-year-old senior at Sylvania Northview High School in Sylvania, Ohio. “Something that’s greater than where we are – going beyond Earth – will bring us together.”

Vanderbilt’s Riley said, “I’m excited about SLS in a very patriotic way. SLS and going to Mars is that big goal that we can all get behind and be excited about as an American people.”


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We’ve Got (Rocket) Chemistry, Part 2

Editor’s note: This is the second in a two-part series on the chemical reactions at the heart of rocket propulsion. Last week, we talked about the liquid engines of the SLS core stage , this week we’ll talk about the boosters.

By Beverly Perry

To give SLS extra power to get it off the ground, twin five-segment rocket boosters, built by Orbital ATK, tower more than 17 stories tall, burn six tons of solid propellant each second and help SLS break free from the clutches of Earth’s gravity.

Solid rocket fuel is the original rocket fuel, dating back to the early fireworks developed by the Chinese centuries ago. For the SLS boosters, aluminum powder serves as the fuel and a mineral salt, ammonium perchlorate, is the oxidizer.

Artist rendition of boosters and engines of during launch
The powerful aluminum-ammonium perchlorate reaction fuels the twin SLS solid rocket boosters.

Aluminum doodleAluminum is the most abundant metal on Earth. It’s also highly reactive. Aluminum is so reactive, in fact, that it’s not found naturally in its pure form but only in combination with other minerals. It’s this ability to readily combine with other metals that makes aluminum so useful. Every day, we use products made of aluminum alloys, or mixes with other metals, for things like beverage containers, covering leftovers, or iPhones. Amazingly, it’s this same stuff that fuels solid rocket boosters.

Ammonium perchlorate, the salt of perchloric acid and ammonia, is a powerful oxidizer (read: majorly explosive). In the boosters, the aluminum powder and ammonium perchlorate are held together by a binder, polybutadiene acrylonitrile, or PBAN. The mixture, with the consistency of a rubber eraser, is then packed into a steel case.

: Interior of booster case after firing
This is what the inside of the empty booster case looked like after the first qualification motor test in March 2015. Preparations are already well underway for the second qualification test this summer.

When it burns, oxygen from the ammonium perchlorate combines with aluminum to produce aluminum oxide, aluminum chloride, water vapor and nitrogen gas – and lots of energy.

Nitrogen doodleThis reaction heats the inside of the solid rocket boosters to more than 5,000 degrees Fahrenheit, causing the water vapor and nitrogen to rapidly expand. Just like in the liquid engines, the nozzle funnels the expanding gases outward, creating thrust and lifting the rocket from the launch pad.

Compared to liquid engines, solid motors have a lower specific impulse – the measure rocket fuel efficiency that describes thrust per amount of fuel burned. However, the propellant is dense and burns quite quickly, generating a whole lot of thrust in a short time. And once they’ve burned their propellant and helped propel SLS into space, the boosters are discarded, lightening the load for the rest of the spaceflight.

So that’s it really. Make water and shoot off an enormous firecracker and you’ve got: Rocket Chemistry. On this scale though, you can’t try this at home. Watch the real show when SLS launches in 2018.


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