**Thanks so much for participating in our Reddit today! Be sure and tune into to our live broadcasts before and during the test - June 27 at 1:30 pm MT will be our live pre-view of the test, and the actual test will be broadcast on June 28 at 8:05 am - both on NASA TV and on NASA's Ustream - http://www.ustream.tv/nasahdtv."

NASA is building the Space Launch System, or SLS, a new heavy-lift rocket and Orion, the crew capsule that will ride on top and carry astronauts. Together, this system gives us the ability to explore deep space. Two solid rocket boosters will help propel SLS out of Earth’s orbit, and Orbital ATK in Promontory, Utah, is building them. We tested a booster last year with the propellant conditioned to the upper limit of its temperature operating range, and our upcoming booster test will be conditioned to the lower limit.

You can watch the test live on NASA TV June 28 at 8:05 a.m. MT, and for more information on SLS, visit http://www.nasa.gov/exploration/systems/sls/index.html. For more information on Orbital ATK, visit www.orbitalatk.com.


• Alex Priskos, NASA SLS Boosters Manager

• Kyle Frame, NASA SLS Boosters Project Coordinator

• Fred Brasfield, Vice President, NASA Programs, Orbital ATK

• Jeff Foote, Deputy Vice President, NASA Programs, Orbital ATK

• Alicia Carrillo, Orbital ATK Engineer

• Earl Benson, Nozzle and Test Area Quality Engineering Manager, Orbital ATK

PROOF: https://twitter.com/NASA_Marshall/status/746400688930861056

Comments: 139 • Responses: 60  • Date: 

JustALittleGravitas7 karma

What actual changes are being made from these boosters vs when they were being used on the Shuttle system?

Also, I don't suppose you have some idea of when the advanced booster will be picked?

NASAMarshallMoon16 karma

This is Alex: There are several differences that make this the most powerful and most safe solid booster ever: 1. SLS booster has 5 propellant segments to 4 segments for the Shuttle – 25 percent more propellant. 2. New environmentally-friendly asbestos-free case insulation and liner 3. New insulation layup configuration 4. New propellant grain 5. New larger nozzle design to handle the increased mass flow of the additional segment 6. New updated avionics 7. Aft attach point moved aft to accommodate core stage structure. 8. The SLS booster is designed for single-use, so the booster doesn’t have the Shuttle booster’s recovery parachutes. 9. Additional Structural stiffeners added to forward skirt 10. Streamlined manufacturing methods for greater affordability. 11. New non-destructive inspection techniques for greater quality assurance and safety

E_Kristalin7 karma

how realistic are non-rocket launch systems like mass drivers and space elevators?

NASAMarshallMoon6 karma

I actually worked on a tethers project at my first job at NASA. It was called MXER and our work primarily focused on material capabilities from a strength as well as long-term survivability within the space environment. Both pose some great challenges and the space elevator requires more advanced technologies than are currently state of the art. Kyle

ehzstreet7 karma

How long does it take for a design to make it from concept to completion?

Does the completion of the SLS Launch Stage Adapter represent a major step toward the completion of the Orion Spacecraft?

Do any of you guys play Kerbal Space Program?

NASAMarshallMoon5 karma

Generally 4-5 years from concept to completion, including testing Need to pass the stage adapter question on to someone else... I've never played KSP, but have been seeing a lot of it on resumes of interview candidates. (note- my friends and I played SimCity... not as cool as space programs!)


NASAMarshallMoon3 karma

A brand new booster design is a multi year project from concept to launch. The SLS booster takes advantage of significant development effort of the space shuttle booster program to reduce the time to completion. JF

Senor_Tucan6 karma

Hey guys! Huge fan here, I’m absolutely stoked to see SLS in action. A couple questions:

-Do the boosters use restrictive or unrestrictive burning? A combination of the two?

-What grain pattern are you using?

Also (I probably shouldn’t be typing this up at work), feel free to give me a job!


NASAMarshallMoon7 karma

The boosters use the same burning approach as used on space shuttle booster. JF

notimetoexplainrun5 karma

Thanks for this Ama!

I've always been fascinated by NASA including going to the Atlantis rollover at KSC and visiting the exhibit a few years later, I'm wondering how the size of the SLS boosters compare to the SRBs from the Shuttle Era?

NASAMarshallMoon6 karma

SRB's from Shuttle were of the 4-segment variety. The SLS version is a 5-segment version with some upgrades, so a little more than 25 feet longer. (side note- I LOVED the Atlantis exhibit!) AC

NASAMarshallMoon2 karma

The SRBs from Shuttle were 4-segment versions. The SLS version is 5-segments. Each segment is a little more than 25 feet. (side note: I LOVED the Atlantic exhibit!) AC

ablack824 karma

I'm going to the booster test in Utah next week as part of the NASA social team! What can I expect to see while I'm there and will you be there?

Also will you wish Brittany a happy birthday? she's a huge SLS fan

NASAMarshallMoon6 karma

Happy birthday, Brittany! You'll see the largest rocket ever designed for human space flight tested - an enormous show of awesome power over 2 minutes. You'll hear the test crew as they work down to T-0 and over 5 tons of propellant burned every second, producing 3.6 million lbs of thrust. Lots of fire, smoke and noise. You'll love it. Yes, I will be there and hope to see you. FB

NASAMarshallMoon5 karma


NASAMarshallMoon5 karma

You will tour the booster manufacturing plant and will get VIP viewing access of the test firing. There will be a live NASA social event as well where you will hear from NASA and Orbital ATK executives talk about future of space program.

Happy B-Day Brittany!!! JF

NASAMarshallMoon5 karma



NASAMarshallMoon3 karma

First of all, Happy Birthday Brittany!!! As for the test - you can expect to hear a pre-test countdown as engineers verify the readiness of each of the subsystems including thrust vector control, data acquisition and ignition systems. Upon ignition a flash of light at the nozzle will be seen followed by a continuous, flame front. Really: you see, then you feel it (shock wave), then you hear it! After that point you will hear variations in the noise levels as they peak and decline then rise again, this is a pre designed throttling of the system (essentially: we press on the gas, let up, then press on the gas again) - AP

NASAMarshallMoon2 karma

Happy Birthday!!! - EB

digger_ex_pat4 karma

SRB's? Why aren't you working on fusion reactors or warp drive?

NASAMarshallMoon9 karma

If we were, I couldn't tell you ... ;-) AC

Frajer4 karma

How long does it take to design and build a booster?

NASAMarshallMoon7 karma

4-5 years from concept to qualification. There's a lot that goes into it. AC

xBanderoo4 karma

If the Orion capsule is underneath the fairing how will a launch escape procedure work? Will the whole faring be carried away in the event of the LES being used or would you need to deploy the fairing first then escape?

NASAMarshallMoon2 karma

the whole capsule will be carried away in the event of a launch abort scenario...EB

xBanderoo3 karma

I've read that nasa has confirmed the rocket to be orange but a lot of people pictures depict it as being black and white. What color will it be for launch?

NASAMarshallMoon1 karma

The Core stage will be orange based on the foam insulation, which provides thermal protection for storing the super-cooled fuel and oxidizer. While the boosters will primarily be white with accents of orange and grey to compliment the core.

NASAMarshallMoon0 karma


Senray3 karma

Do you really think SLS will fly, beyond an unmanned test flight? It seems very to believe that it will, given that there is still no plan for an operational manned flight.

NASAMarshallMoon2 karma

Thanks for your interest - it's important to us..Actually the second launch is manned. I really do believe it will fly, or I wouldn't be doing this for a living. The hardware needed to fly is being built right now. We've already cast (filled with propellant) 3 of the 10 segments for first flight. This is real! FB

NASAMarshallMoon1 karma

SLS is a manned mission on its second flight. JF

Senray2 karma

Will that flight still fly if ARM is cancelled?

NASAMarshallMoon1 karma

Absolutely for EM-2 mission AC

xBanderoo3 karma

Once SLS gets flying how many launches do you anticipate per year?

NASAMarshallMoon1 karma

As many as budgets will allow - EB

NASAMarshallMoon1 karma

Initially, there will be one flight per year. This may increase to two or three after system operability and mission plans mature. JF

Outofmilkthrowaway3 karma

Wow! So cool to be talking to you guys! My phone almost made me miss your AMA.

So, NASA says this is going to be the most powerful rocket ever built. Is this true? I'm assuming it is. But my question is how are the boosters (as well as the rocket as a whole) going to differ from the one used to launch Orion? Why do we need to re-engineer boosters for this cause?

NASAMarshallMoon5 karma

Yes it is, with 3.6 million pounds of max thrust per booster then adding in the RS-25 engines you get to over 8 million pounds of thrust off the pad at launch and that is only our initial configuration. for the vehicle including two boosters and four RS-25 liquid engines. The initial configuration produces 15 percent more thrust than Saturn V at liftoff and the evolved configuration will produce 20 percent more. - AP

NASAMarshallMoon2 karma

I'm not familiar with Orion Herald. Are you thinking of the Orion EFT-1 launch in 2014?

Outofmilkthrowaway2 karma

Yes that is what I'm thinking of. Sorry, I was using dictation software. Not really sure where it picked up Herald from. haha.

NASAMarshallMoon3 karma

That's OK. Orion EFT-1 was launched on a Delta IV Heavy, which did a great job of the mission profile of EFT-1. To go beyond that mission, into deep space and on to Mars, we need a more powerful rocket designed for that mission. FB

zling1113 karma

Do you guys build avionics and software at SLS? If so what assets do you need work there?

NASAMarshallMoon2 karma

Some avionics were developed for SLS and some were developed on previous platforms and application engineered for SLS usage. We are in constant need for smart engineering people particularly in the electronics and computer science disciplines. JF

NASAMarshallMoon2 karma

We have an Avionics and Controls group here. I know the Chief Engineer of that program likes electrical engineers and computer science backgrounds. A blend of electrical and mechanical competencies are a huge plus! AC

bandman4443 karma

First of all, good luck on the test!

This will be the cold version of the test. What effect does the coooler tempurature have on: thrust, burn duration, total impulse, ablative usage? Are these significant to the flight envelope of SLS?

NASAMarshallMoon4 karma

Cold propellant burns slightly slower than warmer grain. This acts to depress pressure, thrust and lengthens the action time. The cold test is more significant to demonstrating the operating environmental envelope. JF

ditty_333 karma

Hello NASA and Orbital ATK! I'm a Mechanical Engineering student currently working at a previous NASA prime contractor called Neptec. I have been following the SLS and Orion progress extensively because there isn't anything much cooler than BLEO space flight ! My question is, How many variations of the SLS are currently under development for different payloads/travel distance and how confident are you that it will make the first launch date, aka no non-weather related delays?

Thank you and you guys are awesome!!

NASAMarshallMoon5 karma

Currently, the first flight in 2018 is the Block 1 configuration which is rated for 70 metric ton lift capability. Future configurations of SLS will require the larger Exploration Upper Stage, which will lift 105 metric tons. Reaching the full potential of SLS will require more powerful boosters with a significant increase in performance over existing boosters.

NASAMarshallMoon5 karma

We are currently working the baseline configuration now. We have plans in work for an upgraded concept to support future missions as needed. We are working toward the first launch in 2018 with high levels of confidence. AC

kylesalcedo3 karma

Good luck on your qualification test! I'm a student pursuing physical therapy, but I've always been interested in the engineering behind aeronautics and the design behind all of the structures that help us learn more about space.

  1. What are the biggest obstacles when turning a design concept to completion?

  2. While working with your team, how do their unique perspectives influence the way you want to move your profession forward? Is there anything specific that helps you bring out the best in your team?

NASAMarshallMoon4 karma

Anytime you're taking something from paper to product it provides difficulty in many areas, including tooling, facilities, materials, and of course processing. Being as prepared as possible and having a system that can react quickly and adequately when things don't go as planned is critical, and not easy. Having different perspectives is critical to getting the best ideas out in the open. It challenges you to think more openly and moving forward you want a culture that promotes that environment. Always let everybody be themselves. If anybody on the team is uncomfortable you won't get their best effort and ideas. - EB

NASAMarshallMoon2 karma

The biggest key to bringing concept to completion begins with good detailed up front planning followed by the recognition that issues will arise and including contingency plans to resolve them. There is no substitute for similar previous experience...while not required it can simplify the avoidance of many previously learned lessons.- AP

NASAMarshallMoon2 karma

  1. The biggest challenges in developing a launch platform are determining where you want it to go and how much it should carry. Ground infrastructure is key to developing a safe launch range. The launch vehicle configuration needs to optimized including minimizing inert weight of each stage.

  2. We have a terrific team of experienced technical professionals and we motivate the team by giving them difficult problems to solve and allow their innovation to deliver high value solutions that meet needs of the space industry. JF

fond_nemesis2 karma

Hello, do satellites use rockets to position or navigate to any specific place or location around space/ earth?

NASAMarshallMoon1 karma

Satellites typically are launched to orbit on top of a multi stage rocket. They are maintained in position with small motors and/or pressure bottles. JF

Image8132 karma

How do liquid and solid rockets compare. It seems like all the new companies are using liquids?

NASAMarshallMoon3 karma

they each have their benefits, and rockets are often at their best when using both, depending on how many stages are required, trajectory, payload, orbit, etc - EB

NASAMarshallMoon2 karma

New endeavors continue to include both liquid and solids. They have different performance characteristics that are selected based upon mission requirements. One major characteristic is that liquid engines tend to have more moving parts but higher potential in-space performance. Solid motors have few moving parts and greater potential thrust capability. KF

cruddyhoneybadger2 karma

What do you think of elon musk?

NASAMarshallMoon3 karma

The work that our commercial partners are doing is very important to achieving our overall space exploration mission. Today's role for our commercial partners is focused on efficient access to low earth orbit(like the International Space Station). The efforts of Elon Musk and others are driving efficiency and innovation into this portion of the endeavor.

NASAMarshallMoon1 karma


NASAMarshallMoon2 karma

He's a good talker, great at PR - EB

cruddyhoneybadger2 karma

So NASA thinks he's full of hot air? SCANDAL

NASAMarshallMoon1 karma

Not at all. We're all partners in space exploration. FB

NASAMarshallMoon1 karma

I like the bravado and willingness to fail to learn. To quote Elon: "Space is hard." AC

NASAMarshallMoon1 karma

Mr. Musk is doing lots of very cool things in lost of arenas, including space. So are we. FB

TheDuskDragon2 karma

How are the temperature operating range limits determined? Also, if either test fails (for both temperature extremes), what would be the contingency plan for future tests?

NASAMarshallMoon1 karma

This temperature operating range limit maximizes launch availability windows and is established based on statistical evaluation of observed weather conditions. Maximizing the launch windows becomes critical for deep space missions. We've already conducted our hot motor qual test (this is our cold test). We've successfully tested the precursor booster to cold, so we don't expect any failures. We have contingency plans in place but are planning for success. AC

MrTrevT2 karma

Can you reschedule QM 2 test to a Friday or Saturday so I may attend?

NASAMarshallMoon4 karma

We will evaluate that. Umm no. There are many attendees that would be disappointed. Can you get out here on Tuesday?

NASAMarshallMoon4 karma

Slightly above my pay grade...EB

leemthompy2 karma

-What is the expected probability of success for the test? -If successful, how long before the SLS sees active duty? -What are the initial primary missions for the SLS?

Thank you!

NASAMarshallMoon7 karma

I'll just say very, very high. The first expected flight for SLS is in 2018. SLS is capable of being used for a variety of missions from manned spaceflight aimed at eventually getting to the moon to unmanned missions to explore Europa...EB

NASAMarshallMoon3 karma

Good question - this is our final qualification test and our confidence is very high. If successful NASA plans on launching the first time in 2018. There are lots of components from all parts of the SLS vehicle and Orion capsule being built all over the country as we speak. FB

grahambalamba1 karma

I've heard that solid rocket boosters are dangerous on a manned spacecraft. If true, why is NASA pursuing using SRB's on the SLS?

NASAMarshallMoon3 karma

No - solids and liquids are both similar when considering reliability and explosive hazard. Both systems have hazards that require management and SLS incorporates an abort system that uses solid propulsion to take the crew to safety during an anomaly. The specific characterizations of this issue are often over simplified while reality is much more nuanced. The key in either case is to properly employ hazard mitigations into the design. AP

NASAMarshallMoon1 karma

Space launch vehicles that leave earth's orbit use energetic materials that need to be designed and used safely whether liquid or solid propellant or manned or unmanned spacecraft. Solid propellants are inherently stable but not as easily throttled. Liquid propellants are more volatile and more easily throttled. The key to optimal launch vehicle design effectively managing the hazards associated with all energetic elements.

spacemika1 karma

Does the change from Mission to Mars to Return to the Moon impact the design or intended usage of SLS?

NASAMarshallMoon1 karma

No- still need to transport people and cargo AC

MetalLava1 karma

(I've been counting down the hours to see this IAMA!!!)

I did a paper on the SLS system a while back, but I haven't brushed up on the details enough to know which technology-based questions to ask.

Can I ask a more personal-centered question, though? I'm a student planning to major in aerospace engineering because I basically want your job. Designing, building, testing...all that jazz involved with putting stuff in space up there. I'm a little bit overwhelmed by the fact that I get to talk to you folks! Anyways back on focus. So I'm terribly interested in that path. Do you have any tips on how to get there? I've been obsessed with NASA and rockets and the like since practically when I was born. I've got passion, skills...what else do I need? How did you get where you are?

Also, do any of you guys have an opinion on Embry-Riddle?

NASAMarshallMoon6 karma

This is Kyle. First of all, thank you for your question and your interest in SLS. Your selection of majoring in aerospace engineering is an awesome choice if you're interested in designing, building, testing, and flying rockets! My degree is actually in mathematics so any technical degree can put you on the path.

NASAMarshallMoon6 karma

Embry-Riddle is a very good school for Aerospace! We had an intern from there last summer.

As far as tips: Get as much experience as you can! Internships are now really important to gain experience for making yourself stand out for full-time employment. At Orbital ATK, we require a 3.0 GPA, US citizenship or US person, and classical degree. As a hiring manager, I like to see people with passion and interest. Generally speaking, most people who go to an accredited university and meet that criteria could all do the job. We want people who love to do the job! If you show interest (and knowledge from company research) and passion, you'll stand out so keep it up! STEM clubs and volunteer opportunities help too. Keep it up!


NASAMarshallMoon3 karma

The first, most obvious, part is to focus on math and science and strive to develop your physics-based understanding. Second, take things apart. Understand how stuff works. If something around the house breaks, try to fix it. Then later you'll be able to take your practical understanding of how stuff works and combine it with physics and math. this kind of understanding will help start you down and engineering path...EB

Knutsop1 karma

Why is it that blimps are not used as launch platforms? If you were to build a Hindenburg size blimp potentially double hulled (exterior helium fully encapsulating an interior of hydrogen) made with modern materials. Would you be able to get a blimp up to the height where Baumgartner did his jump from (120,000 ft)? That would make it so you could launch a rocket in any weather (the blimp would float above inclement weather), drastically reduce fuel requirements (less distance to travel to NEO and reduces weight do to less gravity), which means you could increase payload size or reduce launch costs. not to mention, a 100% (minimal H, and He loss) reusable first stage.

I would love to know why this wouldn't work

NASAMarshallMoon2 karma

There are various air launch systems in use today. Typically, a fixed wing aircraft is used. There have been balloon launched rockets and this is a great question.

talymo300 karma

Hello! I am a 35 year old female Lead Web Developer who aspires to work at NASA. I would like to become a software engineer there and was wondering if you could give me some advice about what degree would benefit me on my track to achieving my goal, I would greatly appreciate the guidance.

My goal is to work on the software systems that are behind some of your amazing projects.

I am currently working as a Lead Web Developer and have been doing web development for close to 6 years now. I am looking into getting back into college to finish up my Bachelors Degree (and hopefully my Masters after that!) and would love to be aligned on the right path to give me the greatest odds of success. It has been my dream for years to work for NASA and am constantly amazed at all the new discoveries and world changing breakthroughs that are being achieved there. I know I am a little bit older and am already approaching at a disadvantage because of that, but I am very dedicated and will do everything I can just to have a shot at my dream.

I have done quite a bit of research on what degrees are appreciated/accepted at NASA and have decided on a Bachelors in Computational Science with a minor in Computer Science, then going back to get my Masters in Physics/Computer Science. Is this a good path?

Any advice you can offer me to align myself for the best opportunity to work for you guys would be greatly appreciated. I know my odds of achieving this goal are about 0.0004% but I couldn't die a happy old woman if I didn't try.

NASAMarshallMoon3 karma

There are tons of opportunity related to internship programs (pathways) and regular employment opportunities as advertised on USA jobs. Getting out and meeting NASA employees at various technical forum can prove to be beneficial. Also reaching out to contractors who support NASA directly can open up significant opportunities and be a key first step. - AP

MrTrevT2 karma

I think these guys are from Orbital ATK, not NASA.

NASAMarshallMoon3 karma

FYI- We have Orbital ATK and NASA MSFC reps here! AC

Beyonder4560 karma

Why NASA still working with 70's Booster Tech?

NASAMarshallMoon3 karma

Booster technology evolves but physics stays constant. The improvements are usually focused on safety and reliability improvements and cost efficiency. What was produced in the 70's forms a basis for propulsion technology but the current state of the art has come a tremendous way in casing, insulation, propellant and nozzle areas. Guidance systems are completely different today than earlier era. JF

NASAMarshallMoon2 karma

We have utilized existing assets to minimize initial costs as the SLS program evolves, that said there are several new technologies which have been incorporated in this booster that are state of the art including: internal insulation system - that is environmentally friendly and preforms much better than previous systems. All new avionics and controls. And newly developed non-destructive inspection techniques to ensure the highest reliability. -AP