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

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.

Computer model of a shock wave at the front of the SLS vehicle at the time of booster separation during launch.

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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The Path to the Pad

2016 is well underway. Another year over, another year begun.

For the SLS program, it means we’re even further past the halfway point toward launch readiness. It’s been only four years since the program officially began in September 2011, and we’re working toward being ready in less than three years for our first launch.

Artist’s concept of SLS stacking at Kennedy Space Center — The day this is a photograph instead of an artist’s concept will be a good day.

The bulk of the first four years was focused on completing the design. To be sure, there was smoke and fire and bending metal as we tested boosters and engines and began building the barrels for the core stage of the rocket. Building on the foundation of the Space Shuttle Program allowed us to move quickly into testing of the engines and boosters, and the design work on the core stage progressed rapidly enough to allow us to begin early manufacturing, and all of that was preparation for what would come when we completed the critical design review of the plans.

An RS-25 engine being raised into the test stand — RS-25 Engine 2059 is currently in the stand for testing at Stennis Space Center. A few years ago, it powered Atlantis’ longest mission, and a few years from now, it will loft SLS’ first crew into space.

With the design work all but done, the push toward the pad is well underway, and there’s a lot of work that entails.

For the rocket to roll out to the pad for launch, each element of the vehicle has to arrive at the Vehicle Assembly Building at Kennedy Space Center to be stacked together with the Orion crew vehicle. And each part has its own road to get there.

For the upper stage portion of the vehicle, which will push Orion out of Earth orbit and into deep space, to be ready to fly, test articles will be built of the adapters that connect the upper stage to the rest of the rocket and to Orion, along with a test article of the upper stage itself. These three test articles will be placed in a stand together, and subjected to stresses and strains to make sure they’re ready for launch. Based on the results of that test, the actual flight articles of the upper stage and adapters will be completed and transported from Marshall Space Flight Center in Huntsville, Ala., to Kennedy Space Center.

For the solid rocket boosters to be ready to fly, qualification motor tests will take place at Orbital ATK in Utah. The results of those tests will pave the way for processing, fueling and completion of the flight boosters, using hardware already at Kennedy Space Center. The boosters will be the first piece of SLS to be stacked in the VAB at Kennedy.

For the 200-foot-tall core stage, which its large fuel tanks and RS-25 engines to be ready to fly, the engines and the stage itself must each undergo individual preparation, and then be integrated together. Tests will be conducted at Stennis Space Center in Mississippi of individual engines, to make sure the RS-25 is ready for the environment it will encounter during launch. Test articles will be built of the large pieces that make up the core stage, and will be transported from Michoud Assembly Facility outside New Orleans to Marshall, where they’ll be placed in large test stands – which have to be built for this purpose – to undergo structural testing. Using the results of those tests, the actual first flight core stage will be completed. Engines will be transported from Stennis to Michoud to be integrated into the core stage, which will then be transported back to Stennis for the largest rocket test firing since the Apollo era. Once it has been tested, the stage will then be shipped down to Kennedy for stacking.

And that’s just the big pieces. In the meantime, work must be done on things like making sure the software that controls the rocket is ready to go.

A new SLS test stand being built at Marshall Space Flight Center — At Marshall Space Flight Center, work is taking place now on the stands that will be used for the test versions of core stage components.

We’ve already made a good start on this “building” phase of the program. In March of last year, we conducted the first qualification test of the solid rocket boosters, and we’re currently preparing for the next, which will take place later this year. At the same time, we’ve started working on the flight hardware for the boosters for SLS’s first launch.

We’ve completed the first series of individual engine tests, using an unflown development engine, and are about to start the second early this year, using an engine that has flown on shuttle missions and will fly again on the second flight of SLS.

We’re almost finished with the upper-stage element test articles, and will use them to conduct structural tests over the course of this year. At the same time, work has already begun on the actual upper stage that will be used to push Orion beyond the moon on SLS’s first flight.

We’re well underway building the pieces that will be used to finish the core stage test articles and the stands on which they’ll be tested. Very soon, we’ll be welding together test articles of the rocket’s liquid hydrogen and liquid oxygen tanks, as well as other core stage components. Those, in turn, will be followed by the flight articles for the first core stage.

It’s an exciting time, and making it more exciting is the fact that this work is taking place in the modern era of digital media, giving you an unprecedented look at the process. As we continue to grow closer, one step at a time, to launch, you’ll be able to follow us every step of the way.

Next Time: May The Forces Be With You

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Orion, At Your Service (Module)

What do NASA’s Orion spacecraft and nuclear-powered airplanes have in common? Here’s a hint: It’s something they also both have in common with actor Samuel L. Jackson.

The answer, of course, is that they’ve all been to NASA’s Plum Brook Station in Sandusky, Ohio.

The Orion service module test article with a model of SLS — The piece of hardware on the left fits roughly were the NASA logo is on the rocket to the right.

Plum Brook, a branch of NASA’s Glenn Research Center, was originally created to allow the agency to conduct nuclear research, first related to airplanes and then to nuclear rockets. Today, it’s a unique facility that allows testing that replicates extreme conditions encountered in spaceflight – from vacuum and thermal environments found in orbit to launch-like acoustic levels that would turn a human body into a puddle.

On an average day, the Space Power Facility at Plum Brook is engaged in tasks like using a a vacuum chamber made of aluminum equivalent to about one billion soda cans to test large payload fairings for SpaceX rockets. And on special occasions it’s used for more unique purposes, like serving as a set for Marvel’s The Avengers (in case you’ve ever wondered why there was a NASA banner hanging behind Jackson’s Nick Fury in the opening scene).

I had the opportunity to visit Plum Brook last month for the arrival from Europe of a test article of the Orion crew vehicle’s service module.* Orion, of course, is the aforementioned deep-space spacecraft, which will be launched on SLS to enable human missions beyond the moon and eventually to Mars. Orion is designed to meet the robust demands of human space exploration, from providing life support to keep up to six astronauts healthy and safe to withstanding the high temperatures generated by a high-speed entry into Earth’s atmosphere.

In order to do that, Orion has requirements that dwarf those of a mission to low Earth orbit. Even after it separates from SLS, Orion will need more than twice as much propellant as a spacecraft on an orbital mission. It will have to have four times the ability to scrub carbon dioxide from the atmosphere, and will have to carry five times as much oxygen and drinking water.

Infographic of Orion capabilities — Just some of the ways Orion is designed uniquely for a unique purpose.

Which is where the service module comes in. It’s a combination of a propulsion system and a storage unit for all those helpful things like air and water that keep astronauts alive while traveling hundreds of thousands of miles from home. Orion’s service module is provided by the European Space Agency, in a partnership agreement that has its roots in NASA’s cooperation with ESA on the International Space Station. The service module builds on the success of the European Automated Transfer Vehicle, which has carried cargo to the space station since 2008.

Work is well underway on the service module for the first flight of SLS and Orion on Exploration Mission 1, but, in the meantime, the recently arrived test article will be put through a variety of stresses and loads to make sure the design is ready to fly. Being at the event marking the arrival of the test article was a glimpse into the future of international space exploration – an overlapping of different accents and different languages, united in a common message of working together to do things we’ve never before done.

The Red Planet is waiting. And people from around our planet are already working together to get there.

Speakers in the acoustic testing chamber at Plum Brook — The acoustic test chamber at Plum Brook will subject the test article to 163 decibels of sound.

*If you’d like to join Orion and Samuel L. Jackson in having a Plum Brook connection, your chance is coming. Plum Brook Station and Glenn Research Center, in Cleveland, will hold open houses in 2016, on June 11-12 and May 21-22, respectively, in connection with Glenn’s 75^th anniversary.

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Mars: Gateway to the Solar System

The demands of going to Mars are immense.

Meeting that challenge will require delivering our best, and then continuing to do better.

Designed to enable human exploration of deep space, NASA’s Space Launch System will be, from its first launch, the most powerful rocket in the world today. The first SLS to depart Earth will carry about triple the payload of the space shuttle, provide more thrust at launch than the Saturn V, and send Orion further into space than Apollo ever ventured.

But even that power is only a fraction of what is needed for human landings on Mars. To continue the Journey to Mars, we will have to take the most powerful rocket in the world and make it even more powerful.

Engineers prepare a 3-D printed turbopump for a test at NASA’s Marshall Space Flight Center in Huntsville, Alabama — NASA is doing research today on technologies like composite materials and 3-D printing that will be used to make future versions of the rocket more powerful.

Engineers at Marshall’s Space Flight Center, where the program is based, and other engineers across the country, are already in the planning phases for the first major upgrade, which will come in the form of a more powerful upper stage. This will create a version of the rocket that will serve as the workhorse for “Proving Ground” missions that will test out new systems and capabilities in the vicinity of the moon before we heard toward Mars. With the new upper stage, SLS will be able to carry additional payloads to lunar space with Orion, allowing astronauts to make longer stays in deep space.

Then, in order to enable the leap to Mars, SLS will receive new, advanced booster rockets that will make it even more powerful. The SLS Program is already working with industry partners to demonstrate new technologies that will make sure the new boosters are state-of-the-art when they begin flying.

Mars is sometimes discussed as a “horizon goal” in human space exploration. While Mars is a focus of our efforts, it is neither the first step of the journey nor the last. Just as we will develop our capabilities in the Proving Ground near the moon before heading toward Mars, once we have reached the Red Planet, our voyage into deep space will continue.

Space Launch System not only represents a foundation for our first steps on the Red Planet, the robust capability necessary to accomplish that goal will also give us the ability to carry out many other ambitious space missions.

Jupiter hangs in the sky above the surface of a moon — Far beyond Mars, SLS could speed space probes far faster than ever before to the outer solar system.

With the ability to launch far more mass than any rocket currently flying or in development, SLS could be used to help pave the way to Mars with large-scale robotic precursor missions, such as potentially a sample return, that would demonstrate systems needed for human landings.

SLS’s unrivaled ability to speed robotic spacecraft through our solar system offers the potential to revolutionize our scientific expeditions to distant worlds. Reducing the time it takes to reach the outer planets could make it possible to conduct in-depth studies of icy moons that are promising destinations in the search for life.

With payload fairings that make it possible to launch five times more volume than any existing rocket, SLS could be used to launch gigantic space telescopes, which will allow us to peer farther into space, and with greater detail, than ever before, revealing new secrets of our universe.

In addition to the Orion crew vehicle and other large payloads, SLS will be able to carry small, low-cost secondary payload experiments, some not much larger than a lunchbox, providing new opportunities to for research beyond the moon and through the solar system. This will make it possible for groups that otherwise might not be able to afford a dedicated rocket launch to fly innovative ideas that can help pave the way for exploration.

The first launch of the initial configuration of SLS will be just a first step toward these and other opportunities; each upgrade will give us progressively greater ability to explore.

Mars – and the solar system – are waiting.

For more about how NASA is preparing for the Journey to Mars, check out our page, The Real Martians.

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David Hitt works in the strategic communications office of NASA’s Space Launch System Program. He began working in NASA Education at Marshall Space Flight Center in 2002, and is the author of two books on spaceflight history.