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  [SLS] RS-25 (SSME) engine tests (Stennis A-1)

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Author Topic:   [SLS] RS-25 (SSME) engine tests (Stennis A-1)
Robert Pearlman
Editor

Posts: 29406
From: Houston, TX
Registered: Nov 1999

posted 01-12-2012 06:02 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA release
Shuttle engines move from Kennedy to Stennis

The relocation of the RS-25D space shuttle main engine inventory from Kennedy Space Center's Engine Shop in Cape Canaveral, Fla., is underway. The RS-25D flight engines, repurposed for NASA's Space Launch System, are being moved to NASA's Stennis Space Center in south Mississippi.

The Space Launch System (SLS) is a new heavy-lift launch vehicle that will expand human presence beyond low-Earth orbit and enable new missions of exploration across the solar system. The Marshall Space Flight Center in Huntsville, Ala., is leading the design and development of the SLS for NASA, including the engine testing program.

SLS will carry the Orion spacecraft, its crew, cargo, equipment and science experiments to destinations in deep space.


Credit: NASA/Gianni Woods

Above: In the Space Shuttle Main Engine Processing Facility at NASA's Kennedy Space Center in Florida, a transportation canister rolls toward a Pratt Whitney Rocketdyne space shuttle main engine (SSME).

"The relocation of RS-25D engine assets represents a significant cost savings to the SLS Program by consolidating SLS engine assembly and test operations at a single facility," said William Gerstenmaier, NASA’s Associate Administrator for Human Exploration and Operations Mission Directorate.

The RS-25Ds – to be used for the SLS core stage – will be stored at Stennis until testing begins at a future date. Testing is already under way on the J-2X engine, which is planned for use in the SLS upper stage. Using the same fuel system – liquid hydrogen and liquid oxygen – for both core and upper stages reduces costs by leveraging the existing knowledge base, skills, infrastructure and personnel.

"This enables the sharing of personnel, resources and practices across all engine projects, allows flexibility and responsiveness to the SLS program, and it is more affordable," said Johnny Heflin, RS-25D core stage engine lead in the SLS Liquid Engines Office at Marshall. "It also frees up the space, allowing Kennedy to move forward relative to commercial customers."

The 15 RS-25D engines at Kennedy are being transported on the 700-mile journey using existing transportation and processing procedures that were used to move engines between Kennedy and Stennis during the Space Shuttle Program. They will be relocated one at a time by truck.

Built by Pratt & Whitney Rocketdyne of Canoga Park, Calif. the RS-25D engine powered NASA’s space shuttle program with 100 percent mission success.

See here for discussion of RS-25 engine use for the Space Launch System.

Robert Pearlman
Editor

Posts: 29406
From: Houston, TX
Registered: Nov 1999

posted 06-09-2013 10:03 AM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA Marshall Space Flight Center (MSFC) release
Production of Key Equipment Paves Way for NASA SLS RS-25 Testing

NASA plans to begin testing RS-25 engines for its new Space Launch System (SLS) in the fall of 2014, and the agency's Stennis Space Center in Mississippi has a very big — literally — item to complete on the preparation checklist.

Fabrication recently began at Stennis on a new 7,755-pound thrust frame adapter for the A-1 Test Stand to enable testing of the engines that will provide core-stage power for NASA's SLS. The stand component is scheduled to be completed and installed by November 2013.

Above: Design image shows a RS-25 rocket engine installed on the A-1 Test Stand at NASA's Stennis Space Center.

"We initially thought we would have to go offsite to have the equipment built," said Gary Benton, RS-25 test project manager at Stennis. "However, the Stennis design team figured out a way to build it here with resulting cost and schedule savings. It's a big project and a critical one to ensure we obtain accurate data during engine testing."

Each rocket engine type requires a thrust frame adapter unique to its specifications. On the test stand, the adapter is attached to the thrust measurement system. A rocket engine then is attached to the adapter, which must hold the engine in place and absorb the thrust produced during a test, while allowing accurate measurement of the engine performance.

The J-2X equipment installed on the A-1 Test Stand now cannot be used to test RS-25 engines since it does not match the engine specifications and thrust requirements. For instance, the J-2X engine is capable of producing 294,000 pounds of thrust. The RS-25 engine will produce approximately 530,000 pounds of thrust.

Above: Fabrication is under way on a 7,755-pound thrust frame adapter to be installed on the A-1 Test Stand at NASA's Stennis Space Center in south Mississippi.

NASA and the Lockheed Martin Test Operations Contract Group team worked together in designing the new adapter to make sure such requirements were met. They also communicated closely with the Jacobs Technology welding and machine shop teams to make sure what was being designed actually could be built.

The design had to account for a number of considerations, such as specific stresses on the equipment as an engine is fired and then gimbaled (rotated) during a test; what type and strength of bolts are needed to fully secure the equipment; and what materials can be used to build the adapter.

"This is a very specific process," Benton said. "It is critical that thrust data not be skewed or compromised during a test, so the adapter has to be precisely designed and constructed."

The fabrication process itself involves handling and shaping large segments of certain material, which required welders to receive specialized training. In addition, shop personnel had to create a welding procedure for dealing with the chosen construction material. For instance, the area of material being welded must maintain a heat of 300 degrees in order to ensure welds bond properly. That procedure and other specifications are being incorporated into Stennis standards.

"It's a challenging project," said Kent Morris, RS-25 project manager for Jacobs Technology. "It's similar to the J-2X adapter project, but larger. It will take considerable man hours to perform the welding and machining needed on the material. The material used for the engine mounting block alone is 32 inches in diameter and 20 inches thick."

Physically, the adapter is the largest facility item on the preparation checklist for RS-25 testing, but it is far from the only one, Benton said. Additional modifications will be made to the test stand configuration and equipment once J-2X gimbal testing is complete this summer.

Once testing begins, engineers and test team personnel at Stennis will draw on a wealth of engine testing experience. The RS-25 engines, previously known as the space shuttle main engines were tested at Stennis for more than three decades.

Robert Pearlman
Editor

Posts: 29406
From: Houston, TX
Registered: Nov 1999

posted 04-11-2014 04:01 PM     Click Here to See the Profile for Robert Pearlman   Click Here to Email Robert Pearlman     Edit/Delete Message   Reply w/Quote
NASA release
NASA gears up for next set of engine tests for Space Launch System

The RS-25 engine that will power NASA's new rocket, the Space Launch System (SLS), off the launch pad and on journeys to an asteroid and Mars is getting ready for the test stand. And it is packing a big punch.

Engineers at NASA's Stennis Space Center near Bay St. Louis, Miss., are now focusing their attention on preparing the RS-25 engine after completing testing of the J-2X engine April 10. Four RS-25 engines, previously known as space shuttle main engines, will muscle the core stage of SLS for each of its missions. Towering more than 200 feet tall with a diameter of 27.6 feet, the core stage will store cryogenic liquid hydrogen and liquid oxygen that will feed the vehicle’s RS-25s.

Modifications to the engines, like higher thrust levels, were needed on the proven workhorse to prepare them for the SLS. To accommodate a higher thrust level, the number of engines was increased from three, used during the shuttle era, to four. The power level also was increased for each engine.

Engines on the shuttle ran at 491,000 pounds vacuum thrust (104.5-percent of rated power level). After analyzing temperature and other factors on the engine, the power level was increased for SLS to 512,000 pounds vacuum thrust (109 percent of rated power level).

Modifications also have been made to the A-1 test stand at Stennis to prepare for the RS-25's first hot-fire test.

See here for discussion of RS-25 engine use for the Space Launch System.

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