NASA Seeks Cause to Early End of SLS Moon Rocket Green Run Hot Fire Test

NASA Seeks Cause to Early End of SLS Moon Rocket Green Run Hot Fire Test
The core stage for the first flight of NASA’s Space Launch System rocket is seen in the B-2 Test Stand during a hot fire test Jan. 16, 2021, at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. Credits: NASA Television

For SpaceUpClose.com & RocketSTEM

CAPE CANAVERAL, FL –  NASA conducted the long awaited and absolutely critical Green Run hot fire test of all four engines on the core stage for the agency’s Space Launch System (SLS) moon rocket in Mississippi on Saturday, Jan. 16 but the test ended early when the engines shut down only about 1 minute into the planned full duration time of eight minutes.

NASA is now seeking to determine the cause of the premature engine shutdown of the agency’s mammoth Space Launch System (SLS) core stage quartet of engines at the base of the mighty Moon rocket at the agency’s Stennis Space Center near Bay St. Louis, Mississippi.

“Teams are assessing the data to determine what caused the early shutdown, and will determine a path forward,” said NASA.

All four Aerojet Rocketdyne RS-25 core stage engines – recycled from the space shuttle era – did successfully ignite as planned at 120-millisecond intervals at 5:27 p.m. ET (2227 GMT) on the B-2 Test Stand at Stennis Space Center and fired for 67 seconds.

Thus the test was a milestone achievement and marks a major step forward for SLS since NASA did collect a vast quantity of very helpful data.

In fact this test marked the first time that all four engines ignited simultaneously for the Boeing-built core stage.

However the root cause of the engine anomaly must be determined and reliable and robust fixes implemented.

The hot fire lasted only a little more than 1 minute and was far short of the full duration Green Run test NASA and prime contractor Boeing had sought in order to clear the core stage for refurbishment and then shipment by the Pegasus barge for arrival at NASA’s Kennedy Space Center (KSC) launch site on February 25.

“Saturday’s test was an important step forward to ensure that the core stage of the SLS rocket is ready for the Artemis I mission, and to carry crew on future missions,” said NASA Administrator Jim Bridenstine, who attended the test in a post test media briefing.

“Although the engines did not fire for the full duration, the team successfully worked through the countdown, ignited the engines, and gained valuable data to inform our path forward.”

Watch this NASA video of the test:

 

The four RS-25 engines fired for a little more than one minute and generated 1.6 million pounds of thrust during a hot fire test Jan. 16, 2021, at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. Credits: NASA TV

The hot fire test was planned to run full duration and simultaneously fire the four RS-25 engines for about 8 minutes or approximately 485 seconds on the B-2 test stand at  Stennis and generate about 1.6 million pounds of thrust – fueled by cryogenic, or supercold, liquid oxygen (LOX) and liquid hydrogen (LH2) propellant fed into the fuel tanks from six  propellant barges.

The full duration of eight minute was planned because its the same amount of time it will take to send the SLS rocket to space following launch from KSC.

Officials said they needed for the test to run at least about 250 seconds to obtain sufficient data to proceed ahead – at the pretest briefing.

The hot fire is the final test of the Green Run test series, a comprehensive assessment of the Space Launch System’s core stage prior to launching the Artemis I mission to the Moon. Credits: NASA TV

This first SLS core stage is destined to launch the Artemis I mission to the Moon.

NASA had been targeting to launch Artemis 1 by late 2021 – if all had gone well with the Jan. 16 hot fire test.

The hot fire was to be the final test in the Green Run series of eight major tests that began about a year ago.

“For the test, the 212-foot core stage generated 1.6 million pounds of thrust, while anchored in the B-2 Test Stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. The hot fire test included loading 733,000 pounds of liquid oxygen and liquid hydrogen – mirroring the launch countdown procedure – and igniting the engines,” NASA reported.

“Seeing all four engines ignite for the first time during the core stage hot fire test was a big milestone for the Space Launch System team” said John Honeycutt, the SLS program manager at NASA’s Marshall Space Flight Center in Huntsville, Alabama.

“We will analyze the data, and what we learned from today’s test will help us plan the right path forward for verifying this new core stage is ready for flight on the Artemis I mission.”

But the cause is not yet clear and NASA did not offer much in the way of explanations.

“When I left the team a little while ago, they were still beginning to pore through the data, and we will continue to do that over the next several days,” said Honeycutt.

Crews delivered the last of four RS-25 engines for Artemis 1, the first flight of NASA’s Space Launch System (SLS) rocket and the Orion spacecraft, from NASA’s Stennis Space Center near Bay St. Louis, Mississippi, to NASA’s Michoud Assembly Facility in New Orleans on June 27, 2019. The Aerojet Rocketdyne engines are lined up side-by-side on June 28 and will be installed into the SLS engine section Fall 2019. Credit: Ken Kremer/kenkremer.com/spaceupclose.com

The NASA, Boeing and Aerojet Rocketdyne team will need to inspect the core stage and engines and determine fixes and then decide the way forward and if another hot fire test should be conducted or not.

A delay in shipment to KSC seems almost certain – but is TBD at this point

Simultaneously team at KSC are already stacking the Artemis 1 SLS SRB boosters and have finished assembly of the Orion crew vehicle – see our upcoming story and photos.

Jim Bridenstine said it was to early to say if the early shutdown will delay launch of Artemis 1.

During the post test briefing I asked if NASA would proceed ahead with booster stacking and Orion fueling?

Crews delivered the last of four RS-25 engines for Artemis 1, the first flight of NASA’s Space Launch System (SLS) rocket and the Orion spacecraft, from NASA’s Stennis Space Center near Bay St. Louis, Mississippi, to NASA’s Michoud Assembly Facility in New Orleans on June 27, 2019. The Aerojet Rocketdyne engines are lined up side-by-side on June 28 and will be installed into the SLS engine section Summer 2019. Credit: Ken Kremer/kenkremer.com/spaceupclose.com

 

Further details from NASA:

The Green Run series of tests began in January 2020, when the stage was delivered from NASA’s Michoud Assembly Facility in New Orleans and installed in the B-2 test stand at Stennis. The team completed the first of the eight tests in the Green Run series before standing down in March due to the ongoing coronavirus pandemic. After resuming work in May, the team worked through the remaining tests in the series, while also standing down periodically as six tropical storms or hurricanes affected the Gulf Coast. Each test built upon the previous test with increasing complexity to evaluate the stages’ sophisticated systems, and the hot fire test that lit up all four engines was the final test in the series.

“Stennis has not witnessed this level of power since the testing of Saturn V stages in the 1960s,” said Stennis Center Director Rick Gilbrech. “Stennis is the premier rocket propulsion facility that tested the Saturn V first and second stages that carried humans to the Moon during the Apollo Program, and now, this hot fire is exactly why we test like we fly and fly like we test. We will learn from today’s early shutdown, identify any corrections if needed, and move forward.”

In addition to analyzing the data, teams also will inspect the core stage and its four RS-25 engines before determining the next steps. Under the Artemis program, NASA is working to land the first woman and the next man on the Moon in 2024. SLS and the Orion spacecraft that will carry astronauts to space, along with the human landing system and the Gateway in orbit around the Moon, are NASA’s backbone for deep space exploration.

NASA Administrator Jim Bridenstine gives remarks on the agency’s Artemis program, Monday, Dec. 9, 2019, announcing assembly completion in front of the 1st core stage for NASA’s Space Launch System (SLS) moon rocket at NASA’s Michoud Assembly Facility in New Orleans. Credit: Ken Kremer/kenkremer.com/spaceupclose.com

Here is test fire imagery from NASA:

 

Watch our live and complete ‘Stay Curious’ Dec 14 and Dec. 30 , 2020 shows on many space topics including Artemis and human spaceflight

Video Caption: Return and Resurgence of US Human Space Flight:   Learn about what’s new at the Cape with huge increase in launches including SpaceX Crew & Cargo Dragon and ULA Atlas & Delta IV Heavy launches and Holidays in Space as Space Journalists Dr. Ken Kremer and Jean Wright serve as co-hosts on ‘Stay Curious’ on the Dec. 14 edition hosted by American Space Museum and update you on the latest news from the Space Coast…all to bridge the space between us. Credit: Stay Curious/American Space Museum

 

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The core stage Green Run test series of NASA’s Space Launch System (SLS) rocket is currently underway. Crews installed the 212-foot-tall core stage — the same rocket hardware that will be used for the first Artemis mission to the Moon — in the B-2 Test Stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi, for the core stage Green Run test series in January 2020. The comprehensive, eight-part test series, or run, will steadily bring the core stage flight hardware, or new, “green” hardware, to life for the first time. The test series cumulates with a “hot fire” as all four RS-25 engines fire simultaneously. The maximum thrust of the four RS-25 engines during launch and ascent is 2 million pounds. During Green Run testing in the B-2 Test Stand, the RS-25 engine thrust peaks at 1.6 million pounds, which is the maximum thrust the engines produce at sea level on the launch pad. The core stage design will be used for all configurations of the SLS rocket, and the series of eight tests will verify the stage is ready for the first and future Artemis lunar missions. This infographic will be updated with check marks in real time to indicate the progress NASA had made in testing the largest rocket stage the agency has manufactured since the Apollo Program that first sent astronauts to the Moon. Credit: NASA

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Ken Kremer

Ken Kremer

Watch for Ken’s continuing onsite coverage of NASA, SpaceX, ULA, Boeing, Lockheed Martin, Northrop Grumman and more space and mission reports direct from Kennedy Space Center and Cape Canaveral Air Force Station in Florida and Wallops Flight Facility in Virginia. Stay tuned here for Ken's continuing Earth and Planetary science and human spaceflight news. Dr. Kremer is a research scientist and journalist based in the KSC area, active in outreach and interviewed regularly on TV and radio about space topics. Ken’s photos are for sale and he is available for lectures and outreach events.

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