SLS Development Stage UPDATE Thread (2)

[Chris Bergin]

Thread for updates on the development stage for the Space Launch System.

Main Links of use:

Lots and lots of SLS and HLV (pre-SLS) articles - no other news site has come close to the coverage we've provided for SLS:
http://www.nasaspaceflight.com/tag/hlv/
http://www.nasaspaceflight.com/tag/sls/

L2 Members:

L2: Specific SLS Section (already VERY meaty - presentations, updates, engineering discussion, with actual SLS managers/engineers, videos and photos/graphics):
http://forum.nasaspaceflight.com/index.php?board=48.0

Note: This is a dev update thread. This should not cover policy or opinion (along the lines of the aforementioned. Use the Space Policy section for that). All posts need to be updates.

[ChileVerde]

A question about the SLS RS-25s came up in the Mk 1 incarnation of this thread that might relate to a NASA item that just appeared in the J-2X thread:

http://forum.nasaspaceflight.com/index.php?topic=26853.msg1040482#msg1040482
   
Re: SLS Development Stage Update Thread
« Reply #678 on: 2013-04-18, 14:56:11 »
   
From a recent GAO report (http://www.gao.gov/assets/660/653866.pdf page 63):
Quote

[SLS project] officials will not know if the shuttle-era RS-25 engines as currently designed can meet SLS’s performance requirements without significant modifications until the engine preliminary design review.

What are they doing to the SSME that makes its performance uncertain? Are they pushing its throttle level beyond shuttle levels and not sure if that'll work?

http://forum.nasaspaceflight.com/index.php?topic=22010.msg1042504#msg1042504

Re: Live: Testing for the J-2X Upper Stage Engine
« Reply #520 on: 2013-04-22, 18:41:54 »

Hot-fire Tests Steering the Future of NASA's Space Launch System Engines
April 22, 2013

Engineers developing NASA's next-generation rocket closed one chapter of testing with the completion of a J-2X engine test series on the A-2 test stand at the agency's Stennis Space Center in Mississippi and will begin a new chapter of full motion testing on test stand A-1.

<snip>

"The A-1 is designed to allow us to gimbal, or pivot, the J-2X during a live firing and test the range of motion for the engine's flexible parts," said Gary Benton, manager of the J-2X test project at Stennis. "This type of testing hasn’t been performed since the space shuttle main engines were tested on the stand."

Those space shuttle main engines, also called RS-25s, will make a return to the test stand in 2014. A collection of RS-25 engines, which were used to launch 135 space shuttle missions, will be rated to operate at a higher power level and used to launch the core stage of the SLS.

"While we will get valuable data on the engine from the firing and gimbaling of the J-2X, we're also re-testing the function of the A-1 stand," said Mike Kynard, manager of the SLS Liquid Engines Office at NASA's Marshall Space Flight Center in Huntsville, Ala., where the SLS Program is managed. "Using A-1 to work on the J-2X gives us a great opportunity to ensure the stand will be capable and ready to test the RS-25s."

<snip>

[deltaV]

ChileVerde: thanks for pointing that out. That looks like a good guess as to the answer to my question (that you quoted).

[psloss]

As noted elsewhere, NASA has posted the presentation slides from last week's quarterly of the Human Exploration and Operations Committee of the NASA Advisory Council.

The relevant one here is the "Status of Exploration Systems Development (Mr. Daniel Dumbacher)":
http://www.nasa.gov/pdf/742964main_20130418_heoc_dumbacher.pdf

Also posted was a link to a quarterly video:
http://www.nasa.gov/multimedia/videogallery/index.html?media_id=161836271

(This has been running on NASA TV during programming breaks; saw a part of it after the Antares launch, but missed the relevant bit here which is the current target to deliver the 1st core stage from MAF in May, 2016...I assume it would be headed for the B-2 test stand at Stennis shown in both Mr. Dumbacher's and Mr. Gerstenmaier's presentation slides.)

Main page for the Human Exploration and Operations Committee of the NAC, with links:
http://www.nasa.gov/directorates/heo/library/nac/index.html

[93143]

In November 2012, NASA produced a preliminary estimate of $7.65 to $8.59 billion for the 70 metric ton version of SLS.

Is this a total spend or a remaining spend?  It's hard to tell from the document...

[ChileVerde]

http://forum.nasaspaceflight.com/index.php?topic=26853.msg1040482#msg1040482
   
Re: SLS Development Stage Update Thread
« Reply #678 on: 2013-04-18, 14:56:11 »
   
From a recent GAO report (http://www.gao.gov/assets/660/653866.pdf page 63):
Quote

[SLS project] officials will not know if the shuttle-era RS-25 engines as currently designed can meet SLS’s performance requirements without significant modifications until the engine preliminary design review.

Perhaps relevant, perhaps not:

http://www.nasaspaceflight.com/2012/03/sls-specifications-take-shape-development-continues/

For maximum power levels (percent RPL), the RS-25Ds will obtain 109 percent of rated thrust and have a standard throttle range of 65-109 percent – the same throttle range that could have been utilized by the engines with the Shuttle orbiters… though Shuttle typically defined a lower-limit 67 percent throttle and upper-limit 104.5 percent throttle range, with 109 percent reserved for abort contingencies.

<snip>

Comparatively, the RS-25E engines, which will enter service once the RS-25D manifest is depleted due to the lack of recoverability of the Core Stage of SLS to which the RS-25Ds will be mounted, will operate with a maximum power level (percent RPL) of 111 percent, a throttle range of 65-111 percent...

[Steven Pietrobon]

Thanks psloss. Here are two images of the SLS core I extracted from the pdf.

[jacqmans]

News Release Issued: Apr 29, 2013 (8:00am EDT)


ATK Solid Rocket Boosters Complete Major Space Launch System Program Milestone

ARLINGTON, Va., April 29, 2013 /PRNewswire/ -- ATK (NYSE: ATK) has successfully completed its solid rocket booster Preliminary Design Review (PDR) with NASA for the new Space Launch System (SLS). The PDR milestone indicates the booster design is on track to support first flight of the SLS in 2017. The SLS vehicle will support NASA's human spaceflight exploration to all destinations beyond low-earth orbit.

"This is a tremendous milestone for ATK as we work toward building the boosters for our country's Space Launch System," said Charlie Precourt, vice president and general manager of ATK's Space Launch division. "NASA's SLS will enable human exploration for decades to come."

With the successful completion of PDR, the SLS booster design can now proceed with the associated activities required to advance the design toward Critical Design Review (CDR). Additionally, a ground static firing of qualification motor-1 is planned for later this year at ATK.

"The booster PDR was successful and speaks to the importance of a collaborative design process with our NASA customer" said Fred Brasfield, ATK vice president, Next-generation Booster.

The SLS booster PDR is a significant step toward providing the necessary technical and programmatic information needed for NASA to obtain approval to proceed with development of the Space Launch System—which will support a variety of missions of national and international importance.

[newpylong]

Stennis Test Stand Modifications for SLS Core testing

http://www.nasa.gov/exploration/systems/sls/b2stand.html#.UX6IwBb2JIc.facebook

[renclod]

... "Status of Exploration Systems Development (Mr. Daniel Dumbacher)":
http://www.nasa.gov/pdf/742964main_20130418_heoc_dumbacher.pdf
...

Thanks !

What I find fascinating is the "upper superstructure" on page 8.
That is new to me. Oh dear, oh gosh ! level 18. The stage must be supported at the intertank. OK.

[catdlr]

Link http://www.nasa.gov/exploration/systems/sls/b2stand.html

The B-2 Test Stand at Stennis, originally built to test Saturn rocket stages that propelled humans to the moon, is being completely renovated to test the SLS core stage in late 2016 and early 2017. The SLS stage, with four RS-25 rocket engines, will be installed on the stand for propellant fill and drain testing and two hot fire tests.

[Steven Pietrobon]

Here's what the SLS core will look like in the B-2 test stand. Should be pretty awesome when they do they the test.

[CNYMike]

Thanks for posting the test stand info.  It's a good reality check to remember just how much work is going into SLS; even with exisiting technology, it's still a new rocket.

[Mark S]

"You came here in that thing? You're braver than I thought!"

First thing that came to my mind when I saw that picture.

"What a piece of junk!". Yeah, but I'm sure that once the test core is mounted, it'll do the Kessel run in less than twelve parsecs.

Whatever that means.

Cheers!

[russianhalo117]

Here's what the SLS core will look like in the B-2 test stand. Should be pretty awesome when they do they the test.

Here is the NASA Article about this published on 29.04.2013:
ARTICLE LINK:

Apollo-Era Test Stand Being Prepared for SLS Core Stage Testing
04.29.13


Before NASA's new Space Launch System (SLS) flies to space on its inaugural mission in 2017, it will fly in place at the agency's Stennis Space Center in Mississippi.

The B-2 Test Stand at Stennis, originally built to test Saturn rocket stages that propelled humans to the moon, is being completely renovated to test the SLS core stage in late 2016 and early 2017. The SLS stage, with four RS-25 rocket engines, will be installed on the stand for propellant fill and drain testing and two hot fire tests.

"These tests will help us understand how the spacecraft and engines behave and provide critical information for ensuring mission safety," said Rick Rauch, manager of the B-2 Test Stand Restoration, Buildout and Test Project. "After all, if there are problems, it's better to address them on the ground than in the air."

NASA is developing the SLS to send humans deeper into space than ever before -- to places like an asteroid and Mars. The SLS will launch NASA's Orion spacecraft and other payloads from the agency's Kennedy Space Center in Florida. The SLS program is managed at Marshall Space Flight Center in Huntsville, Ala. The first test flight of SLS will be in 2017. The rocket will send an uncrewed Orion spacecraft around the moon.

Stennis engineers were asked early in the SLS development process to determine the cost of restoring the B-2 stand to the condition needed for green run testing of the spacecraft’s core stage. A green run is the first time the engines are assembled into a single configuration with the core stage and fired at nearly full-power. This will test the compatibility and functionality of the system to ensure a safe and viable design.

The team spent 18 months conducting structural, mechanical and electrical system evaluations to assess the work needed since Apollo- and space shuttle-era testing.

Once the decision was made to proceed with core stage testing, Stennis engineers began converting original hand-drawn facility blueprints into computer models so design work could be completed. The actual renovation work was divided into three phases: restoration, buildout and special test equipment.

"In the first phase, we are restoring the test facility to its original design condition, where it could be used to test any number of stages," Rauch explained. "In the second phase, we will focus on building out the stand specifically to accommodate the SLS core stage. Then, in the third phase, we will complete the structural, mechanical and electrical interfaces required to test the core stage."

Each phase involves assessment, design and contractor support. In the end, no area of the stand will be left untouched, including all structural areas, as well as supporting mechanical, electrical and piping systems. The fundamental design of the stand will not be changed since it originally was built to test rocket stages.

However, the SLS stage is different from the Saturn stages and the space shuttle main propulsion test article installed and fired on the stand in earlier years. It is taller, standing 212 feet. To lift the stage into place, the derrick crane atop the stand must be extended 50 feet. The stand’s weight and thrust takeout structures also must be modified, and a higher support frame must be erected. The process will involve repositioning an existing 1.2 million pound frame about 20 feet and building a new 100-foot-tall superstructure atop it.

"The teams at the Stennis Space Center are doing a great job preparing the B-2 facility," said John Rector, SLS Stages Green Run test manager at Marshall. "We're on track to begin testing there in 2016. It's an exciting time for NASA as we establish a new national capability for future space exploration." Demolition work began on several test stand levels late last summer. Structural restoration has begun. Work is to be completed in time for delivery of the SLS core stage in 2016, with installation and testing to follow.
 
 

Media Contact:
Kim Henry, 256-544-0034
Marshall Space Flight Center, Huntsville, Ala.
[email protected]

Rebecca Strecker, 228-688-3249
Stennis Space Center, Miss.
[email protected]

[Chris Bergin]

Article on the QM-1 test and the advanced boosters:

http://www.nasaspaceflight.com/2013/05/full-steam-ahead-atk-sls-booster-drive/

[HappyMartian]

Chris, thank you for the lovely article!

Hearing about the ongoing progress of the SLS is always good! 

[Starlab90]

http://www.nasa.gov/pdf/746689main_SLS_Highlights_April_2013.pdf

The April Monthly Report is now available.

[AnalogMan]

NASA Awards Contract to Modify Mobile Launcher
CONTRACT RELEASE : C13-023 May 8, 2013

WASHINGTON -- NASA has awarded a contract to J.P. Donovan Construction Inc. of Rockledge, Fla., to modify the mobile launcher that will enable the agency's Space Launch System (SLS) heavy-lift rocket to send humans to an asteroid, Mars and other new destinations in the solar system.

The work under this firm fixed-price $20.7 million contract will begin in June and be completed in 18 months.

The mobile launcher is located at NASA's Kennedy Space Center in Florida. Kennedy is expanding its capabilities to support the SLS rocket and ground support infrastructure. The modifications will enable the mobile launcher to meet vehicle processing deadlines and the launch manifest for SLS.

SLS' first launch is scheduled for 2017. It will be a flight test to send an uncrewed Orion spacecraft into lunar orbit. NASA's asteroid initiative, proposed in the agency's budget request for fiscal year 2014, would use SLS and Orion to send astronauts to study a small asteroid that will have been redirected robotically to a stable orbit near the moon.

Midwest Steel Inc. of Detroit will be a major subcontractor to J.P. Donovan Construction.

http://www.nasa.gov/home/hqnews/2013/may/C13-023_ML_Mods.html

--------------------------------------

This is a description of the work covered:

This contract is for the modification of the existing Ares-I Mobile Launcher (ML) for the new Space Launch System (SLS) at Kennedy Space Center, Florida. This contract includes removal and storage of existing system components, equipment, and materials for reuse/reinstallation; demolition of system components and structure not to be reused; modification of structural elements and installation of new structural elements; reinstallation of salvaged equipment and materials, and installation of new systems, equipment, and materials. Heavy structural demolition and construction will be performed on approximately half of the existing ML base (MLB). Temporary foundations and shoring will be required to support the remaining MLB and ML tower (MLT) structure during deconstruction/demolition and reconstruction. Modifications to the MLT Electrical Equipment Rooms include removal and modification of Air Conditioning ductwork, and electrical and communication cable trays, and relocation of lighting fixtures. Accurate weights of all items and material removed from the ML and all items and material installed on or in the ML shall be determined, documented, and provided for record. The primary deconstruction, demolition, and construction site is the ML Park Site #3 at Kennedy Space Center, Florida.

http://prod.nais.nasa.gov/cgi-bin/eps/synopsis.cgi?acqid=156193&type=award

[ChileVerde]

More about RS-25Ds and Es:

http://www.aviationweek.com/awmobile/Article.aspx?id=/article-xml/AW_05_06_2013_p22-574390.xml

<snip>

For example, the first four SLS flights will use surplus RD-25D space shuttle main engines, four at a time. The engines flew three at a time on much shorter vehicles than the towering SLS, which also will accelerate faster off the pad. That will create inlet pressures on the order of 300 psi, a higher level than the RD-25D can accommodate with only minor modifications, according to SLS chief engineer Garry Lyles. But the test stands at Stennis Space Center can only deliver 260 psi at the inlets, so the engines will be throttled back on the initial flights to hold the inlet pressures at 260 psi, Lyles says. The test facilities will be uprated when the follow-on RD-25Es come on line, he says.

<snip>

So what does this mean in the greater scheme of things for the ever-ongoing discussions of what SLS Block Whatever is going to be?

P.S.: Presumably the throttle-back will only happen during the later part of core burn, when the mass has decreased enough that the acceleration needed to produce inlet pressures > 260 is reached. When might that be and what effect would it have on IMLEO?

P.P.S.: Forgot about head in the above P.S. Inlet pressure depends on height of fuel above it in the tank as well as acceleration. Acceleration depends on total mass of vehicle, including remaining fuel.  Rocket engineer help needed.