#journeytomars – Page 3 – Rocketology: NASA’s Space Launch System

A Model Employee

This week, I’d like to introduce guest blogger Jared Austin, a fellow writer on the SLS Strategic Communications team, for a peek into a part of the SLS team that is rarely seen, but creates some of our most-seen tools. — David

Few people know Barry Howell and what he’s done for the space program for decades. Neither astronaut nor engineer, through his work as a master model maker Barry has helped NASA visualize spacecraft before they existed.

For more than 40 years, Barry’s “office” has been a space model workshop filled with the past, present and futures of NASA. Barry has created models of many of NASA’s greatest endeavors – from the mighty Saturn 1B and Saturn V, to the iconic Space Shuttle, to early concepts of the International Space Station, to the Hubble Space Telescope, and many other vehicles. Those models aren’t the mass produced, off-the-shelf toys that little Timmy or Sarah receives for their eighth birthdays. Barry’s models are works of both artistic and technical mastery that are painstakingly crafted to scale in a variety of sizes from models that will fit on your desk to a giant that is over 12 feet tall.

Barry Howell with a freshly updated 1-to-50 scale model of SLS.

You don’t last forty years at a job unless you’re extremely passionate about what you do. Barry’s craft is a rare calling – there are only a small handful of modellers at Marshall Space Flight Center, and only a few NASA centers have model shops. Model makers who get a job like this tend to keep it for a long time, so turnover is low and opportunities are infrequent. Barry came to the job from a background in machining, which he started working while in high school. But when there is an opening in the model shop, there really is only one job qualification – be the best at what you do. There’s no particular education or experience requirement, unmatched skill is the determining factor.

Over the course of his career, Barry’s work has helped solve the agency’s most challenging problems, letting engineers visualize the hardware they are designing and building, and to prove concepts such as the shade on Skylab. After Skylab’s launch, NASA had only 10 days to design and build a sunshade for the space station. Barry helped build a model to demonstrate that the umbrella-like shade that Marshall engineers were designing would properly shield Skylab from the sun’s heat. And his work is rather unique within NASA.

Now Barry is taking his decades of experience in modeling all types of NASA systems and using it to produce models of America’s next great rocket, the Space Launch System.

A row of Saturn-era models in the model shop archive — In decades past, Barry created his models directly from vehicle engineering blueprints.

During his tenure in the model shop, Barry has seen changes in technology and process, along with classic methods that have stood the test of time. In the old days of Saturn and early Shuttle, each and every model would be carefully machined according to actual blueprints that allowed Barry to ensure they were precise representations of the real rockets. Working with aluminum or plexiglass blocks, Barry would carefully drill into blocks with a mill or strip away pieces with a lathe, using nothing more than his focused eye, steady hands, and well-honed judgment to carve the individual parts of the rocket from those blocks.

Today, for SLS, model production is a combination of old and new techniques. There’s no longer a need to individually handcraft each model that’s produced; resin casting allows for mass production of models, allowing the model shop to churn out the models at a faster rate and lower cost. But in order to produce the mold for that casting, the old ways are still best. To this day, Barry produces his initial master for each model line with the meticulous same mill and lathe machining process that he used during Saturn.

Close-up of parts for SLS models — In order to capture the fine detail of an official Marshall model, Barry machines the prototype for each model series the shop produces.

Recently, though, even more modern techniques have entered the model shop in the form of 3D printing, creating small astronaut figures, handheld models of the rocket, or small versions of the SLS engines. It’s a new area that the modelers have just begun to explore and holds many possibilities for improving the way they make SLS models going forward.

“I truly love every part of the model-making process, as well as the variety of different models that I’ve gotten the chance to make at NASA,” Barry said. “And the young guys I get to work with, they come up with a lot of great ideas on how to make things even better.

Barry has also been very gracious in passing on his knowledge to others. Modelers who create their own models at home will often request Barry’s inputs to help them make custom-made parts that look more realistic.

Now, as Barry rides off into the sunset of retirement in a couple of months, he’ll be leaving behind a legacy of models showing NASA’s greatest technological achievements. Barry has helped tell the exploration story and by capturing NASA history in 3D for decades.

Next Time: A Model Worker

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Next Giant Leap, No Small Steps

Our focus today at the Space Launch System (SLS) program is on building a new rocket – the most powerful in the world. On its first test flight, Exploration Mission-1, SLS will carry atop it an uncrewed Orion spacecraft, which will someday carry astronauts on a journey to deep space.

A similar scene was unfolding at NASA 48 years ago. On Nov. 9, 1967, the Saturn V rocket launched for the first time, carrying an Apollo spacecraft.

Less than two years later, a Saturn V rocket and Apollo spacecraft sent three astronauts sailing through the void between two worlds, culminating in two members of the crew becoming the first to set foot on another celestial body. The words spoken as the first boot dug into the powdery gray lunar regolith took their place among the most famous ever said.

“That’s one small step for [a] man; one giant leap for mankind.”*

Launch of Apollo 4 — The launch of Apollo 4 was the first from NASA’s Kennedy Space Center in Florida.

With SLS, Orion, and a revitalized space launch complex, we are developing capabilities for our next pioneering endeavor – a journey to Mars.

We continue to make progress toward that journey. Testing has begun on the boosters and engines for the Space Launch System rocket. The One-Year Crew is currently aboard the International Space Station, learning more about living in space for long durations. Our robotic explorers on Mars discovered flowing water and the history of the Martian atmosphere. The Orion vehicle made its first spaceflight, traveling 15 times higher than the orbit of the space station before successfully returning to Earth. These accomplishments, and many more over the last year, bring us closer to the “next giant leap” to Mars, but are all important in their own right. The journey to Mars is hard and the “small steps” along the way aren’t really that small.

And that’s the general idea behind a set of new videos we’re launching today – “No Small Steps.” The challenge of going to Mars is monumental, and it’s going to take a monumental rocket to make it possible. In an entertaining and informative format, “No Small Steps” gets into the “how” of making that happen – taking rocket science and making it relatable to answer questions like how you power a rocket designed for Mars, how you build a rocket the same size as the Saturn V but make it more powerful, how SLS combines the best of NASA’s greatest launch vehicles and makes it even better. We’ll release the next two installments about a month apart, so stay tuned.

Because when it comes to our journey to Mars and beyond, there are no small steps.

https://www.youtube.com/watch?v=https://www.youtube.com/watch?v=TOYXa9jx-TI[/embedyt]

Next Time: A Model Employee

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*My take on the “for man”/”for a man” discussion: Neil was pretty awesome either way.

Movies, Mars Missions and Why Murphy Was An Optimist

If Murphy’s Law were actually true, things would arguably be much easier.

The old adage that “Anything that can go wrong will go wrong” has a reputation of being the apogee of pessimism, but think about how much simpler it would make things if it were true. Spaceflight is full of unknown possibilities, and if Murphy’s Law were really true, you’d only have to prepare for the worst of them.

It’s true for a college exam and it’s true in life or in engineering – it’s not the hard questions that will get you, it’s the ones you never imagined you’d be asked.

There’s a movie out now that captures the spirit of that. “The Martian” tells the story of Mark Watney, an astronaut on Mars who, to put it lightly, gets the opportunity to learn about what can go wrong in space exploration, and his survival depends on working with the NASA team back on Earth to answer questions none of them had ever imagined.

In many ways, “The Martian” is a spiritual successor to “Apollo 13,” both the 1995 movie and the 1970 NASA mission on which it was based. On that mission, a failure in an Apollo service module put the lives of the crew in jeopardy, and only through quick thinking, hard work and a lot of endurance was the crew able to survive.

Both movies are edge-of-your-seat stories about the risks of spaceflight and the merits of duct tape, but while one is fiction and the other is based on a true story, they both are ultimately, in a very real way, stories about NASA — about who we are, and about how we rise to the challenge of answering those unexpected questions.

The real-life carbon-dioxide scrubber assembly from Apollo 13 — A square peg in a round hole — The real-life carbon-dioxide scrubber assembly that helped save Apollo 13.

I’ve talked to engineers who have cited Apollo 13, both the mission and the movie, as something that inspired them to pursue engineering. There’s a scene in the movie where a collection of the items aboard the spacecraft are dumped on a table on Earth, and the engineering team is challenged to use them to figure out how to put a square peg in a round hole. More than one person has told me they saw that scene and said, “THAT’S what I want to do!”

The Apollo 13 mission has been described as being perhaps “NASA’s greatest moment.” I talked once with an astronaut who said this title should really go to a 10-day span in May 1973. When the Skylab space station launched on May 14, its first crew was supposed to follow it on the next day. An anomaly during launch caused the heat shield to be lost and the solar power system to be crippled, endangering the space station. In 10 days, NASA figured out multiple ways to save Skylab, designed and built two different solutions, and was able to launch the first crew on May 25. Apollo 13 was primarily a story of a crew and mission control, but the Skylab rescue was a nationwide effort.

You may never see a movie about the Skylab rescue. The world may pay more attention when lives – real or fictional – are in danger, but answering the unknown is something we do every day. When we do it successfully, it means that we prevent those lives from being endangered in the first place.

It made me happy that one of the first conversations I had with a coworker about “The Martian” wasn’t about what was right or wrong with the movie, but what could have been done differently to make sure the situation it depicts never happened in the first place. On a program developing a new vehicle, our job right now isn’t solving Apollo 13- or The Martian-style problems, it’s preventing them.

Which doesn’t mean we don’t have challenges on the Space Launch System program. We prepare for the worst and we prepare for the best and sometimes we get the unknown. A material doesn’t function in reality the way it does on paper. A proven system behaves differently in a new environment. And when that happens, just like in those movies, we roll up our sleeves and we find an answer to the unexpected question.

And the moments when we do, the moments you never see in movies when we make sure the next Apollo 13 never happens or the next Mark Watney is never stranded on Mars – THOSE are NASA’s greatest moments.

(For more about the Apollo 13 and Skylab rescues, along with other great “NASA Hacks,” check out this feature.)

Next Time: Who’s The Boss?

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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.

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.

https://www.youtube.com/watch?v=https://www.youtube.com/watch?v=dOOHJrqIJqY[/embedyt]

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Making History, Again

https://www.youtube.com/watch?v=https://www.youtube.com/watch?v=SjjRN6KAoi0[/embedyt]

Ask anybody what an astronaut does, and they’ll talk about going on space missions. And, to be sure, that is part of being an astronaut. A rather cool part of being an astronaut.

But, strictly on time spent, it’s also the smallest major part of the job. Back in the Space Shuttle Program, astronauts would spend years on the job of which only weeks were spent in space. If that sounds like it would be frustrating, you have to remember two things: 1) The going-into-space part is really amazing. 2) The not-going-into-space part is also really amazing.

While they’re not in space, astronauts spend a substantial amount of time training, which can range from simulating spaceflight on the ground to traveling the world meeting scientists behind cutting-edge research. They also get to work closely with the NASA team on a variety of different projects, including the development of future space vehicles and systems.

When space shuttle commander Hoot Gibson was selected as an astronaut in 1978, NASA was still three years away from the shuttle’s first launch. Years before he first flew the shuttle, he got to be involved in its development and see it being built. He had a front-row seat for the genesis of the future of American spaceflight, and got to be part of making it happen.

The work we’re doing today on Space Launch System (SLS) in many ways resembles the space shuttle work that Gibson and his classmates got to witness almost 40 years ago. In some ways, it very strongly resembles it – for example, we’re once again testing RS-25 engines at the same facility they did back then, albeit with numerous upgrades over the years.

I’ve had the opportunity to hear Hoot Gibson talk about his shuttle experiences, and to share about the work we’re doing today. As someone who grew up during the shuttle era and a student of its history, it’s an incredible honor that we get to carry forward that legacy with SLS, and to write the next chapter of this history.

In this video, Gibson looks back to the days of the shuttle and forward to the future of exploration. And as we continue to work toward that future, we hope you’ll join us on the journey.

Next Time: Mars: Gateway to the Solar System

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The Journey to Mars!

A graphic showing an astronaut above the Mars horizon with a rover on the surface — NASA’s Journey to Mars is not simply a human exploration mission; it will bring together much of the best of what NASA does.

How do you get to Mars? You build a rocket, and go.

OK, it’s actually a bit more complex than that. A lot more complex, really. But that’s still a vitally important step. We’ll come back to why in a minute.

First, let’s talk about that “complex” part.

Mars is hard. Really hard.

To start with, Mars is far, far away. At its closest, it can come within 34 million miles of Earth, but that’s a once-in-millennia approach. Usually, if the distance gets within the low 50s, that’s really close. At farthest, Mars is about 250 million miles away. Distance means it takes time to get there.

As you travel that distance, there’s a giant ball of gas in the center of the solar system that really wants to kill you. Once you leave Earth, you’re being constantly bombarded with radiation from our own sun and distant stars.

Then there’s the fact that, if you wanted to design a planet that would be hard for humans to land on, Mars would be a good start. The atmosphere is thick enough to combine with the gravity to make an Apollo-style powered descent difficult, but it’s too thin to make a Shuttle-style glide or Orion-like parachutes easy.

Once you make it past the distance, through the radiation, and to the surface, Mars is still inhospitable. Back in 1972, following a detailed survey of planetary conditions, noted Mars expert Elton John summarized that it ain’t the kind of place to raise your kids, and for the moment that’s not a bad assessment.

All of these challenges are substantial. All of these challenges can be overcome.

A graphic explaining NASA’s three-phase Journey to Mars through Earth Reliant, Proving Ground and Earth Independent phases — Not only is NASA’s Journey to Mars the most ambitious mission the agency has undertaken, it will consist of a series of stepping stones that will also be some of the most ambitious missions we’ve ever flown.

NASA’s Journey to Mars is a holistic approach to solving those challenges, to landing humans on Mars, and to answering key scientific questions about Mars, its environment, its history and its habitability.

This Journey is not something NASA is planning to do; it’s something we are doing, right now, in numerous ways, combining the best of our experiences and abilities in a variety of fields.

Robotic explorers are today orbiting the planet and driving across its surface, teaching us more about the conditions there in order to answer those scientific questions and help us prepare for human exploration.
Astronauts aboard the International Space Station are conducting research regarding living in space for the long durations a Mars mission will require, learning more about how to maintain both equipment and the human body during the journey.
Scientists and engineers are working to mature the advanced technologies that will be needed to solve the complex challenges like radiation protection and entry through the Martian atmosphere.
We are also building the robust systems that we need to carry out the trip. The Exploration Flight Test-1 of the Orion crew vehicle in December 2014 was a major milestone, and the first flight of Space Launch System will be another. Later will come in-space propulsion systems, deep-space habitats, and more.

We’re still in the early phases of the Journey, when our human spaceflight is still “Earth-Dependent,” relying on the supply line and other benefits that come from proximity to our home planet.

Soon, we will begin a series of increasingly ambitious “Proving Ground” missions, traveling farther into space and testing new systems and capabilities.

Finally, when we’ve demonstrated we can be “Earth-Independent,” we’ll be Mars-ready. It will be time to take the next giant leap – possibly first into Mars orbit or the Martian moons, and ultimately to take our first steps on the surface of another planet.

Which brings us back to how you get to Mars – You build a rocket, and go.

All of those challenges will ultimately be solved with hardware – habitats to live in on the long journey, shielding to protect from radiation, supersonic decelerators to descend through the Martian atmosphere, advanced life support for living on the surface, and much more. There will be a lot of that hardware, and some of it will be truly massive. And none of it does any good sitting on the surface of the Earth. If you want to get to Mars, you have to be able to put all of that into space. And that’s where Space Launch System comes in. You have to build a rocket. A big one.

And none of it matters unless you do it. Wernher von Braun went on Walt Disney’s Tomorrowland television program in the 1950s to talk about going to Mars, and much time has been spent talking about going to Mars in the decades since, by NASA, other countries, technical societies, industry, and others. You have to talk about Mars, you have to plan, before you can go, but talking and planning alone won’t get you there. You have to do something.

Today NASA is doing something in a way that neither we nor anyone have before. NASA’s Journey to Mars is unique in that it is the first and so far only time that any organization has actually begun building systems designed for human exploration of Mars. We have a long way to go, but we’re taking the first steps.

How do you get to Mars?

You build a rocket.

And go.

Next Time: Four Lessons In Four Years

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Fourth and Very Very Very Long

A graphic showing that SLS would stretch almost from one end of a football field to the other — Comparing space to football is a grand tradition that may well have been started by John F. Kennedy himself, who compared going to the moon with Rice playing Texas in his ‘We Choose to Go to the Moon’ speech. If it’s good enough for JFK, it’s good enough for me.

Ah, September. That wonderful time of year when the air becomes cooler, leaves begin to turn color, and every discussion is required by law to include football metaphors. You certainly won’t see me intentionally grounding such a great opportunity, so let’s talk about what it means to “go long” in human spaceflight.

The first launch of SLS will send the Orion spacecraft into a large lunar orbit beyond the moon. But, really, how does that compare to previous human spaceflight missions? Let’s use a comparison to a football field to find out.

In real life, a football field, from the back end of one end zone to the other, is just slightly longer than the 322-feet-tall SLS. But for the sake of this metaphor, we’re going to scale the distance Orion will reach at its farthest point on Exploration Mission-1 to the length of that field. Imagine you’re standing at the very end of the end zone of an American football field. In the distance, at the far end of the other end zone, 120 yards away, is the farthest point Orion will reach on EM-1. Are you imagining it? Good.

First play, we’re tossing from the back edge of our end zone to the International Space Station. Complete! We’re well on our way! Well, sort of. This doesn’t quite get you out of your own end zone. In fact, at about 230 miles — roughly the driving distance between New York and Washington, DC — you’ve only gained about three and a half inches on our field.

A graphic showing the International Space Station near the end of a football field — The vast majority of time Americans have spent in space has been around the altitude of the International Space Station, but it’s just the beginning of this journey.

For second down, we’re going to be a bit more aggressive. Back in 1966, almost 50 years ago, two astronauts, Pete Conrad and Dick Gordon, set an Earth orbit altitude record of 854 miles on the Gemini 11 mission – the farthest humans have been without heading to the moon. But even when Gordon takes the ball, you’ve only covered a total of one foot.

Third down, aiming farther still. The altitude record reached on Gemini 11 is less than a third of the altitude Orion reached on its first spaceflight, Exploration Flight Test-1, in December 2014. Using that altitude, 3,600 miles, for our next play, we’ll be just over one percent of the way to our goal, at a total of four feet and eight inches from where we started.

It’s now fourth down, and we’re still at the back of our own end zone. For an even longer distance, we’ll use the distance the International Space Station travels during one orbit of the Earth – 26,250 miles. This play gives us our first down, and also put us out of the end zone by almost four feet.

A graphic showing a map of the Earth outside the end zone of a football field — Technically, orbital mechanics means that the physics of two Robonauts both in the same orbit around the Earth throwing a football any substantial distance between them wouldn’t actually be possible. (Besides, wouldn’t it have been easier to throw it the other direction?)

Sticking with Earth orbit distances is getting us nowhere. We’ve got to be even more aggressive. A long Hail Mary throw sends the ball to the far end of the field, where it’s caught … by Neil Armstrong on the moon! The crowd goes wild! TOUCHD… Wait… What? That’s still only at the other eight-yard line? Oh, well. Let’s keep going.

A graphic showing an Apollo astronaut catching a football near the opposite end zone of a football field — For the record, that picture’s not really Neil Armstrong. Also, the football wasn’t really in this picture.

You look toward the end zone, and there’s astronaut Jim Lovell of Apollo 13! He’s open, and you make the pass. On their emergency free-return trajectory around the moon on Apollo 13, Lovell, Fred Haise and Jack Swigert traveled farther from Earth than anyone has ever been, almost 249,000 miles out. But although Lovell went around the moon on two different Apollo missions, he was never able to touch down, and, unfortunately, he doesn’t now, either. Even the human distance record from Earth is short of the end zone, by three and a half yards.

Back in formation, the quarterback steps back, fires to Orion, caught in the very back of the end zone for a 23 and a half yard gain from where Lovell had it! TOUCHDOWN! On EM-1, Orion will travel about 10 percent farther into space than Apollo ever did. Not bad for a first test flight.

A graphic showing Orion at the opposite end zone of a football field — TOUCHDOWN ORION!

And, from there it gets interesting. Since this was just the first possession, you’d better not let that arm get tired – on our field, the trip to Mars will be about a 77,000 yard pass. Now, THAT is going long.

Next Time: The Journey to Mars

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The Engine Experience

https://www.youtube.com/watch?v=https://www.youtube.com/watch?v=08Gv7qDxgUE[/embedyt]

Can I make a confession? To be honest, I was a little bit jaded about going to see last week’s test firing of one of Space Launch System’s RS-25 engines.

Don’t get me wrong, when the opportunity to go came up, I took it in a heartbeat. I was even excited about it.

Let’s put this in perspective. I’ve seen shuttle launches. Not one, but three RS-25 engines, each time. Plus two solid rocket boosters. Stacked together, and heading into space atop a column of sky-splitting light and noise. If you never got to see one, they were pretty amazing.

So one RS-25? Going nowhere? Honestly?

A white cloud emerges from the A-1 engine test stand — With a history of almost 50 years, the A-1 stand was used for tests to make sure the Saturn V and space shuttle were ready for flight.

In case you missed it, in our last two blog posts, we talked about the test stand s and the engines themselves, and you can read about the 535-second test of the 12-million-horsepower engine and see video here.

But what was it like?

If some hypothetical foolish soul were to be naïve enough as to be jaded about an RS-25 test because they had seen shuttle launches, not that anyone would do that, it would be because they failed to appreciate two big differences in watching an engine test.

When you watch an engine test, you’re much closer to the action than you are for a shuttle launch. And the engine doesn’t go anywhere during the test.

The former fact means that you get a better sense of the details of what’s going on. Watching a launch, you see the shuttle rising atop a majestic plume of white. From a football field away, you see just how dynamic that white cloud is as it exits the engines, the speed and violence of the steam leaving the stand. You get a new appreciation of the power those engines are generating. You understand the volume of the engines in a new way as well. Out of curiosity, during the test, I loosened one of my earplugs ever so slightly, and quickly realized how dumb an idea that was. It’s loud. Like, really loud.

The fact that the engine doesn’t go anywhere means that you experience the entire burn. Watch a launch, and it’s ephemerally amazing and then gone. Watch an engine test, and it’s unrelenting. Power and sound washing over you for minute after long minute. More than one person commented to me about having a better sense of what was happening during a launch vehicle’s climb to orbit after witnessing the test.

David Hitt in front of RS-25 engine test — If you photograph a shuttle launch, you have your camera ready and snap as quick as you can. If you photograph a full-duration engine test, you shoot some video when it starts. Then take some pictures. Then watch for a while. Then switch cameras and take some more pictures. Then take a selfie. Then watch some more. Then get someone else to take pictures of you. Then take pictures of them. Then watch some more.

And then, at the end, a surprise I didn’t anticipate at all. In a launch, the end of an RS-25s burn comes in the silent void of space. On Earth, you hear everything. It’s hard to describe the sound that engine made as it ended the test – it reminded me of the astronaut descriptions of the shuttle I wrote about a few weeks ago. It was alive. A rolling growl of a mythic behemoth. Unearthly.

It’s been four years since I stood on a riverside in Titusville, Florida and watched the space shuttle Atlantis climb into the sky for the final time, and I still have years to wait until I watch the first SLS do the same.

To be sure, that future day seemed closer as I watched the RS-25 engine burn for a duration that would have put a spacecraft into orbit. Spaceflight is about speed, and speed is about power. The difference between being on the ground and being in orbit is less about altitude than it is velocity. Push something to 17,500 miles per hour, and it will orbit. Push it harder and faster, and it will go farther. This year, we’ve fired Space Launch System’s engines and boosters and demonstrated that right now we have the power we need to generate the speed. The next trick is completing the capability to keep those very thirsty engines fueled.

But I also came away from the test with a new appreciation for this time we’re in today, between those two launches. When I watched a shuttle launch, I didn’t have any sense of what one RS-25 engine was doing. I couldn’t distinguish it from the rest of the vehicle. Watching the test, you appreciate that engine. The power, the volume, the force of one RS-25. It’s an amazing piece of machinery. People came away with an excitement for seeing the core stage green run test in two years, when four engines will be integrated into the stage and fired together. Understanding what one engine is like, there was an eagerness to see that quadrupled.

The B-2 test stand at Stennis Space Center — Work is taking place today to prepare for an even more impressive test firing in a couple of years, when a 200-foot-tall SLS core stage will be fitted with four RS-25 engines and then placed vertically into the towering B-2 test stand and fired.

In March, we test-fired one of SLS’ solid rocket boosters, and those who were there talk about a similar experience. You didn’t get a sense watching the shuttle of what one SRB was contributing. But take it off the stack and fire it on its own? One SLS booster burns with the equivalent force of seven RS-25s, so you can imagine it’s impressive in its own right.

And it’s not just the propulsion systems. I got to stand within feet of the stage adapter that mated Orion to the Delta IV Heavy rocket used for Exploration Flight Test-1 in December 2014, a twin of which will connect Orion to SLS on our first flight. Look at a picture of SLS, and you barely notice that adapter. Stand next to the thing, and it’s a substantial piece of hardware.

This current period we’re in is about construction, but for me, I love that it has the added benefit of being about deconstruction. About taking one of the most amazing vehicles our species has created, and breaking it down to its parts. About seeing how incredible each of those parts is individually, understanding them better in their own right. About adding and understanding new parts, bigger and more advanced. And then, ultimately, taking those parts and putting them together in a new way to do a new thing.

So, yes, despite my naïve jadedness, I enjoyed watching the test firing. Immensely.

But, wow, am I looking forward to that launch.

Next Time: Exploration Football

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RS-25 Engines: Meeting the Need for Speed

Guest blogger Martin Burkey, the SLS strategic communications team’s resident expert on all things engines, returns this week as we prepare for this afternoon’s RS-25 engine testing event at Stennis Space Center – if you’re not already, follow @NASA_SLS on Twitter and our Facebook link below for more info. — David

Rocket engines are among the most amazing machines ever invented. That’s mainly because they have to do one of the most extreme jobs ever conceived – spaceflight – starting with escaping Earth’s deep gravity well. Orbital velocity, just for starters, is over 17,000 mph, and that only gets you a couple hundred miles off the surface. Going farther requires going faster. Much faster.

The RS-25 makes a modern race car or jet engine look like a wind-up toy.

It has to handle temperatures as low as minus 400 degrees where the propellants enter the engine and as high as 6,000 degrees as the exhaust exits the combustion chamber where the propellants are burned.

It has to move a lot of propellants to generate a lot of energy. At the rate the four SLS core stage engines consume propellants, they could drain a family swimming pool in 1 minute.

The most complex part of the engine is its four turbopumps which are responsible for accelerating fuel and oxidizer to those insanely high flow rates. The high pressure fuel turbopump main shaft rotates at 37,000 rpms compared to about 3,000 rpm for a car engine at 60 mph.

The bottom line is that the RS-25 produces 512,000 pounds of thrust. That’s more than 12 million horsepower. That’s enough to push 10 giant aircraft carriers around the ocean at nearly 25 mph.

If the performance requirement to turn massive amounts of fuel into massive amounts of fire wasn’t enough, an engine can’t take up a lot of mass or area in a rocket. A car engine generates about half a single horsepower to each pound of engine weight. The RS-25 high pressure fuel turbopump generates 100 horsepower for each pound of its weight.

But forget mere car engines. The RS-25 is about the same weight and size as two F-15 jet fighter engines, yet it produces 8 times more thrust. A single turbine blade the size of a quarter – and the exact number and configuration inside the pump is now considered sensitive – produces more equivalent horsepower than a Corvette ZR1 engine.

Expanded view of an RS-25 engine — And this is still only the major components of an RS-25 engine.

On the other hand, when you chug fluids that fast, a hiccup is a bad thing. In the case of a rocket engine, that hiccup is called cavitation. At the least, it robs the engine of power. At worst, it can cause catastrophic overheating and overspeeding. So rocket engineers spend a lot of time making sure fluids flow straight and smooth.

That’s also why they test rocket engines on the ground under highly instrumented and controlled conditions. It’s a lot less costly to fail on the ground than in flight with a full rocket carrying people on board and/or a one-of-a-kind multi-million- or multi-billion-dollar payload.

As rocket engines go, the RS-25 may be the most advanced, operating at higher temperatures, pressures, and speeds than most any other engine. The advantage comes down to being able to launch more useful payload into space with less devoted to the rocket structure and its propellants.

In addition to its power, another key consideration for SLS was the availability of 16 flight engines and two ground test engines from the shuttle program. It’s much harder and more expensive to develop a new engine from scratch. Using a high-performance engine that already existed gave NASA a considerable boost in developing its next rocket for space exploration.

Top of an RS-25 engine during a test firing — The RS-25 handles a wide range of temperatures – super-cold on top, super-hot at the bottom.

The remaining shuttle engine inventory will be enough for the first four SLS flights. As for the maturity part, the RS-25 design dates to the 1970s and the start of the Space Shuttle Program. But it’s undergone five major upgrades since then to improve performance, reliability, and safety. If only we could all upgrade 5 times as we age. Further, much of the knowledge and infrastructure needed to use the available engines and restart production already existed. Another hidden savings in time and money.

In its next evolution, the RS-25 design will be changed to make it a more affordable engine designed for just one flight and certify it to even higher thrust – which it is very capable of – to make SLS an even more impressive launch vehicle.

Next Time: The Engine Experience

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How Is A Test Stand Like A Space Ship?

I’d like to introduce a special guest blogger this week, Martin Burkey. Martin is the SLS strategic communication team’s resident expert on all things engines. As we prepare for next week’s RS-25 engine testing event at Stennis Space Center – if you’re not already, follow @NASA_SLS on Twitter and our Facebook link below for more info – Martin will be filling in this week and next to talk about our engines and how we test them. — David

None of the test stands at NASA’s Stennis Space Center look anything like a spaceship. But they operate a lot like a spaceship, even though none of them will ever leave the ground.

A test stand is designed to make a fire-breathing rocket engine think it’s a spaceship, while at the same time keeping it from taking off for space the way it was made to. Those two requirements account for why test stands look and operate as they do… and why they aren’t as compact, light and sleek as a rocket.

Most of the big Stennis test stands were built in the 1960s to test Saturn rocket engines. Over the years, they’ve continued to serve the nation by testing Space Shuttle Main Engines and other government and commercial rocket engines. Today, the center is buzzing with test activities in support of NASA’s Space Launch System.

The A-1 Test Stand is the focus of testing to adapt the RS-25 –formerly known as the shuttle main engine – to new SLS performance requirements and environments. It will also be used to test engines with new components for the second SLS mission. The B-2 Test Stand is being readied to support testing of the massive 200-foot SLS core stage with its four RS-25 engines.

Thousands of tons of hulking, ungainly concrete and steel hundreds of feet above and dozens of feet below the Mississippi soil keep the engine locked in place for testing under way this year. An intricate network of tanks, pipes, cables and other equipment provides the engine with all the propellants, power, pressure, vacuum, fluids, cooling, data management and other services to – safely and accurately – simulate a full rocket mission from pre-launch preparations to nearly 200 miles in space.

A worker inspects the machinery of an RS-25 engine — A test stands interface with the engine mimics the interface between the engine and an actual launch vehicle.

Why test the RS-25, an engine that flew successfully for more than 3 decades and has over a million seconds of operating time? Because the RS-25 is a complex and finely tuned piece of equipment that requires thorough understanding various component interactions and responses under different conditions. Like other rocket engines, it operates at extremes of temperature, pressure, vibration, etc. that have to be monitored. More specifically, the RS-25 needs to be adapted to SLS requirements and environments such as higher propellant inlet pressure and lower temperature and integrates technology like a new engine controller unit. The test stand environment allows controlled testing of abnormal conditions and more thorough monitoring and observation than the flight environment. Ultimately, it’s better to find problems on the ground than in flight. There’s a saying in rocket testing – “Test like you fly, and fly like you test.” In other words, make the engine do everything on the ground it’s going to have to do in flight, and don’t do anything in flight you haven’t made the engine do on the ground. Why are we testing a proven engine? Because Space Launch System is going to make its RS-25s do new things in flight, but not until every one of them has been done successfully on the ground.

The A-1 stand supporting the current test series provides the RS-25 with liquid hydrogen (LH₂) and oxygen (LOX) propellants. The stand has its own run tanks for propellants but they can also be filled from a 12-inch line running from LOX and LH barges docked near the test stand during test firing. The B test complex is also served by propellant barges, though stage testing relies on the propellant in the stage alone.

Aerial view of the test area at NASA’s Stennis Space Center.

From a safe distance, the Stennis test stands look like crude, utilitarian structures. Up close, they are intricately woven with a network of pipes, cables, and other hardware designed to exercise rocket engines and extract the important data.

The stand provides various gases such as nitrogen and helium for drying, pressurizing and preventing premature combustion in the engine, as well as breathing air for crews working in the engine nozzle before and after testing.

The stand also provides hydraulic and pneumatic pressure to operate the engine propellant valves. There’s electrical power to run the engine controller. There are data cables that carry engine performance information to and from the engine and the vehicle computers and crew. The high speed data system has 186 channels that can record various conditions at more than 100,000 times per second. Four high-speed cameras can record 250 frames per second. Low-speed video includes infrared, black and white and color cameras.

And, of course, there’s water for fire suppression on the stand and water to cool the stand’s ubiquitous “flame bucket” that directs engine exhaust exiting the nozzle at thousands of degrees away from the stand where it rapidly condenses into steam and then into rain that falls downwind. The A-1 bucket consists of 21 slanted deflector segments that make up the deflector seen in pictures. Each segment gets pressurized water, and each segment is drilled with a specific number and pattern of holes that spray water and keep the deflector cool during test firing. During tests, the stand uses 170,000 gallons of water per minute from a nearby reservoir.

The “crew” of the A-1 stand consists of about 50 people, some on the stand until 30 minutes before a test and others in the hardened Test Control Center 200 yards away from the test stand.

So while rocket engine testing may not resemble any real or fictional spaceship, it’s still very much “rocket science” and a critical part of getting NASA’s next great exploration rocket to the launch pad.

Next Time: RS-25 Engines: Meeting the Need for Speed

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