rocket – Page 2 – Rocketology: NASA’s Space Launch System

Five “Secrets” of Engine 2059

Earlier this month, another successful test firing of a Space Launch System (SLS) RS-25 engine was conducted at Stennis Space Center in Mississippi. Engine testing is a vital part of making sure SLS is ready for its first flight. How do the engines handle the higher thrust level they’ll need to produce for an SLS launch? Is the new engine controller computer ready for the task of a dynamic SLS launch? What happens when if you increase the pressure of the propellant flowing into the engine? SLS will produce more thrust at launch than any rocket NASA’s ever flown, and the power and stresses involved put a lot of demands on the engines. Testing gives us confidence that the upgrades we’re making to the engines have prepared them to meet those demands.

If you read about the test – and you are following us on Twitter, right? – you probably heard that the engine being used in this test was the first “flight” engine, both in the sense that it is an engine that has flown before, and is an engine that is already scheduled for flight on SLS. You may not have known that within the SLS program, each of the RS-25 engines for our first four flights is a distinct individual, with its own designation and history. Here are five other things you may not have known about the engine NASA and RS-25 prime contractor Aerojet Rocketdyne tested this month, engine 2059.

1. Engine 2059 Is a “Hubble Hugger” – In 2009, the space shuttle made its final servicing mission to the Hubble Space Telescope, STS-125. Spaceflight fans excited by the mission called themselves “Hubble Huggers,” including STS-125 crew member John Grunsfeld, today the head of NASA’s Science Mission Directorate. Along with two other engines, 2059 powered space shuttle Atlantis into orbit for the successful Hubble servicing mission. In addition to its Hubble flight, engine 2059 also made four visits to the International Space Station, including the STS-130 mission that delivered the cupola from which station crew members can observe Earth below them.

Launch of Atlantis on STS-125 — The engine farthest to the left in this picture of the launch of the last Hubble servicing mission? That’s 2059. (Click for a larger version.)

2. The Last Shall Be First, and the Second-to-Last Shall Be Second-To-First – The first flight of SLS will include an engine that flew on STS-135, the final flight of the space shuttle, in 2011. So if the first flight of SLS includes an engine that flew on the last flight of shuttle, it only makes sense that on the second flight of SLS, there will be an engine that flew on the second-to-last flight of shuttle, right? Engine 2059 last flew on STS-134, the penultimate shuttle flight, in May 2011, and will next fly on SLS Exploration Mission-2.

View of the test stand during the test of engine 2059 at Stennis Space Center on March 10. — The test of engine 2059 at Stennis Space Center on March 10.

3. Engine 2059 Is Reaching for New Heights – As an engine that flew on a Hubble servicing mission, engine 2059 has already been higher than the average flight of an RS-25. Hubble orbits Earth at an altitude of about 350 miles, more than 100 miles higher than the average orbit of the International Space Station. But on its next flight, 2059 will fly almost three times higher than that – the EM-2 core stage and engines will reach a peak altitude of almost 1,000 miles!

Infographic about engine testing — Click to see larger version.

4. Sometimes the Engine Tests the Test Stand – The test of engine 2059 gave the SLS program valuable information about the engine, but it also provided unique information about the test stand. Because 2059 is a flown engine, we have data about its past testing performance. Prior to the first SLS RS-25 engine test series last year, the A1 test stand at Stennis had gone through modifications. Comparing the data from 2059’s previous testing with the test this month provides calibration data for the test stand.

NASA Social attendees with engine 2059 in the background — Attendees of a NASA Social visiting Stennis Space Center being photobombed by engine 2059.

5. You – Yes, You – Can Meet Awesome SLS Hardware Like Engine 2059 – In 2014, participants in a NASA Social at Stennis Space Center and Michoud Assembly Facility, outside of New Orleans, got to tour the engine facility at Stennis, and had the opportunity to have their picture made with one of the engines – none other than 2059. NASA Social participants have seen other SLS hardware, toured the booster fabrication facility at Kennedy Space Center in Florida, and watched an RS-25 engine test at Stennis and a solid rocket booster test at Orbital ATK in Utah. Watch for your next opportunity to be part of a NASA Social here.

Watch the test here:
https://www.youtube.com/watch?v=https://www.youtube.com/watch?v=njb9Z2jX2fA[/embedyt]

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Next Time: We’ve Got Chemistry!

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Time Flies: Next-Generation Rocket Is the Work of Generations

This week’s Rocketology post is by the newest member of the SLS communications team, Beverly Perry.

When NASA’s Space Launch System (SLS) first flies, it will slice through Earth’s atmosphere, unshackling itself from gravity, and soar toward the heavens in an amazing display of shock and awe. To meet the engineering challenges such an incredible endeavor presents, NASA’s Marshall Space Flight Center draws upon a vast and diverse array of engineering talent, expertise and enthusiasm that spans multiple disciplines and, in some cases, a generation. Or two.

Kathryn Crowe is a twenty-something aerospace engineer who tweets from her smartphone and calls herself a “purveyor of the future.” Hugh Brady, on the other hand, began his career at Marshall during the days of punch cards and gargantuan room-sized IBM mainframes with an entire 16 kilobytes (!) of memory.

But if you think these two don’t have much common ground on which to build a strong working foundation, well, think again. Although the two aerospace engineers may be separated by a couple generations, they speak of each other with mutual admiration, respect and enthusiasm. And like any relationship built on a solid foundation, there’s room for fun, too.

Even though Brady’s career spans 50-plus years at NASA, he’s anything but jaded, to hear Crowe tell it. “Hugh still seems to keep that original sense of excitement. I figure if he thinks I’m doing okay, then I must be doing okay since he’s seen almost our entire history as an agency. It’s nice to have him to help keep me straight,” says Crowe, who recently received NASA’s Space Flight Awareness Trailblazer Award, which recognizes those in the early stages of their career who demonstrate creative, innovative thinking in support of human spaceflight. “And, he always tries to bring a sense of humor to everything he does.”

“I’ve enjoyed being mentored by Kathryn,” jokes the seventy-something Brady, who admits to failing retirement (twice, so far) because he loves the space program and can’t stay away. (Also, he said, because he doesn’t care for television. But mostly it’s because he loves space exploration and working with young, talented engineers.)

Crowe and Brady have worked together evaluating design options and deciding on solutions to make the second configuration of SLS as flexible and adaptable as possible. This upgraded configuration – known as Block 1B – adds a more-powerful upper stage and will stand taller than the Saturn V. It could fly as early as the second launch of SLS, which will be the first crewed mission to venture into lunar orbit since Apollo. Block 1B also presents the opportunity to fly a co-manifested payload, or additional large payload in addition to the Orion crew capsule.

Illustration showing the Block 1B configuration of the rocket and 8.4 and 10 meter payload fairing options — The addition of an Exploration Upper Stage to SLS will make the rocket more powerful and open up new mission possibilities.

For Crowe, a self-described “shuttle baby,” working on a future configuration of SLS means the chance to look at the big picture. “I like to have a global view on things. For this particular rocket, we’ve made it as flexible as we can. We can complete missions that we don’t even know the requirements for yet!”

For Brady, “Things have a tendency to repeat.” While technology and solutions continue to improve, some of the challenges of spaceflight will always remain the same. When it comes to wrestling with the challenges of a co-manifested payload, Brady draws on his experience, but focuses on solutions that are tailored for SLS. It’s bringing lessons from the past into the present in order to find the best solution for future missions. “It’s drawing on what we’ve learned from the past but not necessarily repeating the past. We want the best solution for this vehicle,” he emphasizes.

Crowe says the experience and knowledge Brady brought to the table made all the difference when studying options for the SLS vehicle. “Hugh would say, ‘I think we worked on this particular technical problem when we were initially flying.’ He could draw parallels so we didn’t reinvent the wheel,” Crowe says. Since then, Brady has become something of a mentor to Crowe and other younger team members.

“When you put that kind of technical information on the table it gives people better information – information that’s based on prior experience,” Brady says. “We may not pick the same solution, because technology changes over time, but we will have more and better information to use when making decisions.”

“I think that having that kind of precedent to build upon it really is a beautiful thing,” Crowe says.

For his part, Brady says he feels a “comfort” level in passing the United States’ launch vehicle capabilities on to the next generation of engineers and other supporting personnel. “One of the things I find very exciting is to look around and see the young talent around the center with their energy and enthusiasm. I feel good thinking about when I do hang it up – again – that they will carry on and even do more than we did,” he says.

When you ask Crowe if humans will get to Mars, she says, “For sure I think within my lifetime I will see humans on Mars. I think more than ever right now is the right time to return to human spaceflight. We have the right skills and expertise. And when we successfully complete our mission and show that sort of hope to people again, that’s going to be equally as important as technological benefits.”

“That’s the objective,” Brady says. “I can’t wait until we fly again. It’s a tremendous feeling! It’s exhilarating! It’s time.”

https://www.youtube.com/watch?v=https://www.youtube.com/watch?v=gXMhOe1pRKc[/embedyt]If you do not see the video above, please make sure the URL at the top of the page reads http, not https.

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Making a Lot of Fire in Two “Easy” Steps

On one end of the technology spectrum, you have rocket science, mastering the laws of physics to allow human beings to break the chains of gravity and sail through the void of space.

On the other end, you have the earliest humans, first learning to use the world around them in innovative ways to do things they previously couldn’t.

What do these two extremes have in common? Making fire. Just like the secret to learning to cook food was mastering the creation of flames, creating fire is also the secret to leaving the planet.

We just use a much bigger fire.

If you’ve watched the first video in our No Small Steps series you’ve learned why going to Mars is a very big challenge, and why meeting that challenge requires a very big rocket. In the second installment we talked about how NASA’s Space Launch System (SLS) builds on the foundation of the Saturn V and the space shuttle, and then uses that foundation to create a rocket that will accomplish things neither of them could.

Now, the third No Small Steps video takes a step further by looking at the basics of the monumental energy that makes the rocket go up. If you’ve been following this Rocketology blog and the No Small Steps videos, you’re aware that the initial configuration of SLS uses two different means of powering itself during launch – solid rocket boosters and liquid-fuel engines.

But why? What’s the difference between the two, and what role does each play during launch? Well, we’re glad you asked, because those are exactly the questions we answer in our latest video.

With more SLS engine and booster tests coming in the next few months, this video is a great way to get “fired up” about our next steps toward launch.

https://www.youtube.com/watch?v=http://youtu.be/zJXQQv9UZNg[/embedyt]
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Think You’re Stressed? Try Being A Rocket

You know how big the SLS vehicle will be. We described the tremendous power and thrust of just one of the RS-25 engines after last year’s test firings. You may have witnessed live as we fired one of the massive five-segment solid rocket boosters last March. Through all that, perhaps you can imagine how incredible it will be at launch when all four engines and both boosters ignite together to lift this 322 feet tall, 5.75 million pound rocket up through the atmosphere and toward deep space. Imagine the thunderous vibration in your chest even as you stand several miles away.

Artist’s concept of an SLS launch — Note: Actually watching an SLS launch from this close is strongly not advised (or permitted). Orion hardware is being tested to withstand sound levels that would turn a person to liquid.

We’ve talked about how it will feel to be there when the rocket launches. Now, let’s talk about how it would feel to BE the rocket, launching.

Envision the power generated at launch as the engines and boosters throttle up to 8.8 million pounds of thrust. The heat is incredible! The vehicle starts to shake. The engine nozzles, as big and solid as they seem, will warp under the pressure of heat when the engines ignite seconds ahead of the boosters. While still on the pad, the boosters are bearing the weight of the entire vehicle even as they fire up for launch – the weight of almost 13 Statues of Liberty resting on an area smaller than an average living room.

Then, you – the rocket – are released to fly, and up you go. More than 5 million pounds of the weight of the rocket pushing down are now counteracted by more than 8 million pounds of thrust pushing from the opposite direction. Remember those 13 Statues of Liberty? Now the bottom of the rocket is feeling the pressure of 29 of them instead!

And now things are heating up on the front end of the rocket as well. Approaching Mach 1, shock waves move over the entire vehicle. Friction from just moving through the air causes the nose of the vehicle to heat. The shock waves coming off the booster nose cones strike the core stage intertank and can raise the temperature to 700 degrees. The foam insulation not only keeps the cryogenic tanks cold, it keeps the heat of ascent from getting into the intertank structure between the hydrogen and oxygen tanks.

Are you feeling it yet? That’s a lot to handle. These impacts from weight (mass), pressure, temperature and vibration are called “loads.” It’s a key part of the “rocket science” involved in the development of the SLS vehicle.

A load is a pressure acting on an area. Sounds simple, right? There are all kinds of loads acting on SLS, some even before it leaves the launch pad. Tension and compression (pulling and pushing), torque (twisting), thermal (hot and cold), acoustic (vibration), to name a few. There are static (stationary) loads acting on the big pieces of the rocket due to gravity and their own weight. There are loads that have to be considered when hardware is tipped, tilted, rolled, and lifted at the factory. There are “sea loads” that act on the hardware when they ride on the barge up and down the rivers to various test sites and eventually across the Gulf of Mexico and up the Florida coast to Kennedy Space Center for launch. Engineers have to consider every single load, understanding how they will affect the structural integrity of the rocket and how they will couple and act together.

The Pegasus barge that will transport SLS — You’ve probably never thought of “riding on a boat” as rocket science, but SLS has to be designed to handle sea loads as well as space loads.

When SLS is stacked on the mobile launcher at KSC, there are loads acting through the four struts securing the core stage to the boosters and down into the booster aft skirts that have to carry the entire weight of the launch vehicle on the mobile launcher. Then there are roll-out loads when the mobile launcher and crawler take SLS more than 4 miles from the Vehicle Assembly Building to the launch pad. There are many more loads as the vehicle is readied for launch.

How do engineers know the rocket’s ready to handle the loads it has to face to send astronauts into deep space? Step One is good design – developing a rocket robust enough to withstand the strains of launch. However this is difficult as the vehicle needs to be as lightweight as possible. Step Two is digital modeling – before you start building, you run many, many simulations in the computer to a level of detail that would make any Kerbal Space Program fan jealous. Step Three is to do the real thing, but smaller – wind-tunnel models and even scale-model rockets with working propulsion systems provide real-life data. And then comes Step Four – build real hardware, and stress it out. Test articles for the core stage and upper stage elements of the vehicle will be placed in test stands beginning this year and subjected to loads that will mimic the launch experience. Engines and boosters are test-fired to make sure they’re ready to go.

Still want to be the rocket? Stay tuned for more on loads as we do everything possible to shake, rattle, and yes, even roll, the pieces of the rocket, ensuring it’s ready to launch in 2018.

Next Time: No Small Steps Episode 3

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