SLS Development Stage Update Thread

[spectre9]

Thanks for your response Starlab90.

A valuable insight into the engineering capabilities of MSFC. 

I didn't know there was an open competition to build it.

I apologise for being misinformed. 

[ChileVerde]

Anyway, NASA's Dan Dumbacher gave a status briefing on Exploration Systems Development to the NASA Advisory Council on 14 November 2012 (http://www.nasa.gov/pdf/707188main_Dumbacher_ESD_Status_NAC_20121114.pdf).

A question: In the "Core Stage Engine" section of the Milestone Schedule, there's a line for "A-1 Test" and another for "RS-25 Testing (A-1)."  Is that for what's been called the RS-25E? If not, what's happened to the RS-25E and what will SLSes after EM-4 use for core stage engines?

[edkyle99]

Anyway, NASA's Dan Dumbacher gave a status briefing on Exploration Systems Development to the NASA Advisory Council on 14 November 2012 (http://www.nasa.gov/pdf/707188main_Dumbacher_ESD_Status_NAC_20121114.pdf).

A question: In the "Core Stage Engine" section of the Milestone Schedule, there's a line for "A-1 Test" and another for "RS-25 Testing (A-1)."  Is that for what's been called the RS-25E? If not, what's happened to the RS-25E and what will SLSes after EM-4 use for core stage engines?

To my eyes this looks like engine and engine cluster testing using existing engines, with new controllers.  I seem to recall that a few additional current-design engines might be assembled from "spare parts" or manufactured new if needed.  On this chart, at least, there is no sign of an RS-25E development effort before 2025.

 - Ed Kyle

[ChileVerde]

To my eyes this looks like engine and engine cluster testing using existing engines, with new controllers.  I seem to recall that a few additional current-design engines might be assembled from "spare parts" or manufactured new if needed.  On this chart, at least, there is no sign of an RS-25E development effort before 2025.

I think you're right. The Gerstenmaier version has RS-25d in place of the A-1 bit.  There are some differences between the Gerstenmaier and Dumbacher timelines that I don't understand. The attachment crudely juxtaposes them.

[ChileVerde]

On this chart, at least, there is no sign of an RS-25E development effort before 2025.

Reviewing the RS-25E thread that ran here early this year, it appears that it will take about seven years to develop the engine.  If EM-5 is in 2027, as is suggested by the schedule, then we should see indications of RS-25E development activity ca. 2020, no?

[kch]

Anyway, NASA's Dan Dumbacher gave a status briefing on Exploration Systems Development to the NASA Advisory Council on 14 November 2012 (http://www.nasa.gov/pdf/707188main_Dumbacher_ESD_Status_NAC_20121114.pdf).

A question: In the "Core Stage Engine" section of the Milestone Schedule, there's a line for "A-1 Test" and another for "RS-25 Testing (A-1)."  Is that for what's been called the RS-25E? If not, what's happened to the RS-25E and what will SLSes after EM-4 use for core stage engines?

If I'm not mistaken, the "A-1" refers to this ...

http://sscfreedom.ssc.nasa.gov/etd/ETDTestFacilitiesA1.asp

... not to a name change for the RS-25E.

[edkyle99]

On this chart, at least, there is no sign of an RS-25E development effort before 2025.

Reviewing the RS-25E thread that ran here early this year, it appears that it will take about seven years to develop the engine.  If EM-5 is in 2027, as is suggested by the schedule, then we should see indications of RS-25E development activity ca. 2020, no?

That sounds about right, but another option would be to defer RS-25E and just build more RS-25D (SSME) engines.  There's plenty of time on the schedule to build plenty of engines, and steady production would likely offer cost reduction opportunities.

 - Ed Kyle

[Starlab90]

http://www.nasa.gov/pdf/712431main_SLS_Highlights_Nov2012.pdf

The November monthly highlight is now posted.

[Ben the Space Brit]

Regarding RS-25E: Assuming the figure of 7 years is broadly accurate, that means that the first units would be available around 2020.  That's pretty close to when they'll be needed anyway.  So, unless the funding appears for more SLS missions in between the current proposed dates for EM-1 and EM-2 (maybe probe launches or a very large cargo delivery to the ISS) then there won't be a need for more than 10 SSMEs for SLS at the very most.  I'm pretty sure the extant stock is enough for that.

That said, a bit of me is a bit worried that we're banking on a very limited utilisation for SLS to compensate for a backwards engine dev program (upper stage before core stage).  I still think they should have migrated the J-2X contracts to RS-25E; it isn't as if J-2X is going to be used for more than a decade but... ah, I guess no-one was asking me.

[AnalogMan]

http://www.nasa.gov/home/hqnews/2012/dec/HQ_12-440_SLS_Core_Stage_Milestone.html

NASA'S Space Launch System Core Stage Passes Major Milestone, Ready to Start Construction
RELEASE : 12-440  Dec. 21, 2012

HUNTSVILLE, Ala. -- The team designing America's new flagship rocket has completed successfully a major technical review of the vehicle's core stage. NASA's Space Launch System (SLS) will take the agency's Orion spacecraft and other payloads beyond low-Earth orbit, providing a new capability for human exploration.

The core stage preliminary design review (PDR) was held Thursday at NASA's Marshall Space Flight Center in Huntsville, Ala., and included representatives from the agency and The Boeing Co. Boeing's Exploration Launch Systems in Huntsville is the prime contractor for the core stage and its avionics. Marshall manages the SLS Program.

"Passing a preliminary design review within 12 months of bringing Boeing on contract shows we are on track toward meeting a 2017 launch date," said Tony Lavoie, manager of the SLS Stages Element at Marshall. "We can now allow those time-critical areas of design to move forward with initial fabrication and proceed toward the final design phase -- culminating in a critical design review in 2014 -- with confidence."

The first flight test of the SLS, which will feature a configuration for a 70-metric ton lift capacity and carry an uncrewed Orion spacecraft beyond the moon, is scheduled for 2017. As the SLS evolves, a two-stage launch vehicle using the core stage will provide a lift capability of 130-metric tons to enable missions beyond low-Earth orbit and to support deep space exploration.

The purpose of the PDR was to ensure the design met system requirements within acceptable risk and fell within schedule and budget constraints. An important part of the PDR was to prove the core stage could integrate safely with other elements of the rocket's main engines and solid rocket boosters, the crew capsule and the launch facilities at NASA's Kennedy Space Center in Florida. Core stage designers provided an in-depth assessment to a board of engineers comprised of propulsion and design experts from across the agency and the aerospace industry.

"Each individual element of this program has to be at the same level of maturity before we can move the program as a whole to the next step," SLS Program Manager Todd May said. "The core stage is the rocket's central propulsion element and will be an optimized blend of new and existing hardware design. We're building it with longer tanks, longer feed lines and advanced manufacturing processes. We are running ahead of schedule and will leverage that schedule margin to ensure a safe and affordable rocket for our first flight in 2017."

The core stage will be built at NASA's Michoud Assembly Facility in New Orleans using state-of-the-art manufacturing equipment. The plant continues modifying its facilities and ordering materials for construction of the rocket. Michoud has built components for NASA's spacecraft for decades, most recently, the space shuttle's external tanks.

For more information about the Space Launch System, visit:

http://www.nasa.gov/sls

[jacqmans]

Boeing Completes Preliminary Design Review for Space Launch System Core Stage

Ahead of schedule for design and development
 
Team will use schedule advantage to ensure safe, affordable rocket

 
HUNTSVILLE, Ala., Dec. 21, 2012 -- Boeing [NYSE: BA] and NASA on Dec. 20 completed the Preliminary Design Review (PDR) for the Space Launch System (SLS) core stage and avionics, validating the design of the rocket that will send humans beyond low Earth orbit to places like the moon, an asteroid and ultimately Mars.
 
The PDR is a comprehensive review that demonstrates that the design meets all system requirements within acceptable risk constraints, establishing approval for proceeding with detailed design. The first mission in 2017 will be an un-crewed loop around Earth's moon, to be followed by a crewed mission.
 
"Design reuse and concurrent design and production planning helped us to quickly create a core stage preliminary design that integrates heritage and new designs, all less than a year from contract award. This is an important element of our schedule management approach," said Jim Chilton, vice president for Boeing Exploration Launch Systems.
 
Boeing and NASA achieved three important milestones in the past year -- System Requirements Review, Systems Design Review and now PDR. Boeing can now proceed to the Critical Design Review, the final step -- expected in 2014 -- that officially gives Boeing the authority to proceed into production. Boeing continues to develop production capability for the heavy-lift rocket at NASA's Michoud Assembly Facility in New Orleans.
 
"We are running ahead of schedule and we will use the extra time to ensure a safe and affordable rocket," said Frank McCall, Boeing SLS deputy program manager.
 
The SLS program employs a growing Boeing Space Exploration workforce in Huntsville, Ala., and New Orleans, as well as in Houston; Huntington Beach and El Segundo, Calif.; Cleveland, Ohio; and Titusville, Fla.
 
http://boeing.mediaroom.com/index.php?s=43&item=2544

Photo-1: In this photo, Boeing weld engineer Tim Livengood confirms the setup on a friction stir weld test fixture at NASA's Michoud Assembly Facility in New Orleans in support of the SLS.

Photo-2: In this photo, Boeing weld technician Richard Oramous, weld engineer Tim Livengood and weld technician Gary Bennett (left to right) observe a Self Reacting Friction Stir Weld development test weld in progress at NASA's Michoud Assembly Facility in New Orleans in support of the SLS.

[sdsds]

Congratulations to NASA and Boeing! Essentially the same information is at http://www.nasa.gov/exploration/systems/sls/corepdr.html. There's a photo there (attached) showing a fabricated isogrid panel of the type that will be used for the structure. Looking closely inside each triangle there are features that might be a side effect of milling, but maybe they have other (design) reasons for being there?

[TomH]

Looking closely inside each triangle there are features that might be a side effect of milling, but maybe they have other (design) reasons for being there?

I used the zoom feature. Looks like each triangle has within it a set of 4 concentric progressively smaller equilateral triangles that have less height on the z axis than the large triangles. It is a corrugated pattern. Obviously gives strength.

[clongton]

There's a photo there (attached) showing a fabricated isogrid panel of the type that will be used for the structure.

Which structure? This is a flat panel which cannot be rolled without deforming the isogrid.

[HappyMartian]

Thank you jacqmans! Reading about the progress with the SLS is good news.

[spacejulien]

Looking closely inside each triangle there are features that might be a side effect of milling, but maybe they have other (design) reasons for being there?

I used the zoom feature. Looks like each triangle has within it a set of 4 concentric progressively smaller equilateral triangles that have less height on the z axis than the large triangles. It is a corrugated pattern. Obviously gives strength.

No, it's just the path the milling cutter was programmed to take, there are no changes in height. You won't feel a step with your finger.

E.g., zoom in the first row of triangles, they're not concentric, the milling head went across areas milled before, so obviously can't include intentional changes of height on the z axis.

[sdsds]

There's a photo there (attached) showing a fabricated isogrid panel of the type that will be used for the structure.

Which structure? This is a flat panel which cannot be rolled without deforming the isogrid.

Yet the website claims it is, "the first test panel for the SLS liquid hydrogen tank."

It does seem like any sensible person would form the plate into a barrel section first; then mill the isogrid. But apparently these aerospace manufacturing guys do the wackiest things! Check out Fig. 7 -- "Machined panels at General Dynamics are filled with a low-melting resin to allow easier bending and forming" at http://www.isogrid-sst.com/machine%20design.htm

[EDIT: Ed's reference below expands on this a bit. "For [roll forming] the isogrid pockets should be filled with a suitable filler material to prevent buckling of the members." And also (in section 7.3.3) it discusses the difficulties of machining after forming. See attached.]

[edkyle99]

There's a photo there (attached) showing a fabricated isogrid panel of the type that will be used for the structure.

Which structure? This is a flat panel which cannot be rolled without deforming the isogrid.

See chapter 7 of the following document.
http://femci.gsfc.nasa.gov/Isogrid/NASA-CR-124075_Isogrid_Design.pdf
"To date, waffle construction, unless it is very shallow and used for parts
with compoand curvature, has been machined in the flat and subsequently formed."

The ribs have to be designed to handle the forming loads.  Thor/Delta, Saturn, STS External Tank, etc., followed these procedures.

 - Ed Kyle

[jacqmans]

RELEASE: 13-020

NASA AWARDS SPACE LAUNCH SYSTEM ADVANCED DEVELOPMENT GRANTS

WASHINGTON -- NASA has awarded grants to nine universities for
advanced development activities for the nation's next heavy-lift
rocket, the Space Launch System (SLS).

The agency is providing approximately $2.25 million that will be
shared by all the proposals under this NASA Research Announcement to
seek innovative and affordable solutions to evolve the launch vehicle
from its initial lift capability to a larger, future version of the
rocket, which will carry humans farther into deep space than ever
before. NASA sought proposals in a variety of areas, including
concept development, trades and analyses, propulsion, structures,
materials, manufacturing, avionics and software.

"Partnering with academia on SLS advanced concepts brings new ideas
and vitality to NASA and expands the SLS team of rocket scientists
beyond just the agency," said William Gerstenmaier, associate
administrator for Human Exploration and Operations at NASA
Headquarters in Washington.

The selected universities and their proposals are:
-- "High Electric Density Device for Aerospace Applications," Auburn
University
-- "Challenges Towards Improved Friction Stir Welds Using On-line
Sensing of Weld Quality," Louisiana State University
-- "A New Modeling Approach for Rotating Cavitation Instabilities in
Rocket Engine Turbopumps," Massachusetts Institute of Technology
-- "Algorithmic Enhancements for High-Resolution Hybrid RANS-LES Using
Loci-CHEM," Mississippi State University
-- "Characterization of Aluminum/Alumina/Carbon Interactions under
Simulated Rocket Motor Conditions," Pennsylvania State University
-- "Development of Subcritical Atomization Models in the Loci
Framework for Liquid Rocket Injectors," University of Florida
-- "Validation of Supersonic Film Cooling Numerical Simulations Using
Detailed Measurements and Novel Diagnostics," University of Maryland
-- "Advanced LES and Laser Diagnostics to Model Transient
Combustion-Dynamical Processes in Rocket Engines: Prediction of Flame
Stabilization and Combustion-Instabilities," University of Michigan
-- "Acoustic Emission-Based Health Monitoring of Space Launch System
Structures," University of Utah

For a description of each of the proposals, visit:

http://go.nasa.gov/ULC5iT

"As we make tangible progress on the initial launch vehicle, our
advanced development team is formulating concepts for an evolved
version of the rocket," said Todd May, SLS Program manager at NASA's
Marshall Space Flight Center in Huntsville, Ala. "The work being done
today on SLS is a national and collaborative effort. With faculties
and students engaged now, we look forward to creative, innovative and
more affordable strategies to guide development of the
next-generation heavy-lift launch vehicle."

The SLS is designed to be flexible for launching payloads and
spacecraft, including NASA's Orion Multi-Purpose Crew Vehicle, which
will take humans beyond low-Earth orbit. The rocket will enable the
agency to achieve its deep-space exploration goals and create new
possibilities for scientific discovery.

The period of performance for these grants will be one year with as
many as two one-year options.

The first flight test of NASA's SLS, which will feature a
configuration for a 70-metric-ton (77-ton) lift capacity, is
scheduled for 2017 from NASA's Kennedy Space Center in Florida.

For information about NASA's Space Launch System, visit:

http://www.nasa.gov/sls

[JosephB]

What a slam.
Internet experts have been providing this free for years.