Boeing workers attached the last of five sections of the 212-foot-tall core stage on Sept. 19 – namely the bottom engine section which is one of the most complicated pieces of hardware for the SLS rocket and has been problematic to design and build an caused many delays.
The overall goal is to build the rockets for NASA’s Artemismoon exploration program aimed at landing US astronauts on the lunar south pole by 2024.
The SLS core stage is the largest rocket stage the agency has built since the Saturn V that sent Apollo astronauts to the Moon. It will produce 2 million pounds of thrust powered by four RS-25 engines fueled by liquid hydrogen and liquid oxygen.
“NASA has achieved a historic first milestone by completing the final join of the core stage structure for NASA’s Space Launch System, the world’s most powerful rocket,” said Julie Bassler, the NASA SLS stages manager, in a statement.
“Now, to complete the stage, NASA will add the four RS-25 engines and complete the final integrated avionics and propulsion functional tests. This is an exciting time as we finish the first-time production of the complex core stage that will provide the power to send the Artemis I mission to the Moon.”
The Boeing team bolted the engine section to the stage’s liquid hydrogen propellant tank at the base of the core stage.
I visited Michoud over the summer to see the core stage which at that time was four fifths complete and about 190 feet in length.
See our Space UpClose photos herein.
NASA Deputy Administrator James Morhard was on hand with the media for an update and facility tour during his first visit to Michoud on June 28.
Morhard told Space UpClose that NASA is working hard with Congress to obtain a $1.6 Billion budget boost to the Fiscal Year 2020 budget request for NASA.
The money is required to kickstart development of a human lunar lander and achieve the Trump Administrations new goal of achieving an American lunar landing by 2024 at the south pole with the first woman and next man from NASA’s astronaut corps on the Artemis-3 mission.
The next step this fall is installation of the four RS-25 engines to the base of the engine section by lead contractor, Aerojet Rocketdyne, and connect them to the main propulsion systems inside the engine section.
The engine section “is the attachment point for the four RS-25 rockets and the two solid rocket boosters that produce a combined 8.8 million pounds of thrust to send Artemis I to space.”
“In addition, the engine section includes vital systems for mounting, controlling and delivering fuel from the stage’s two liquid propellant tanks to the rocket’s engines.”
The RS-25 engine installation by the Aerojet-Rocketdyne team will take several months with completion expected in December.
Thereafter the core stage will be shipped on the Pegasus barge to NASA Stennis Space Center to carry out the Green Run testing involving a full duration engine test to qualify the stage for launch on the Artemis 1 mission.
The green run test campaign will last about six months or so.
“Boeing expects to complete final assembly of the Artemis I core stage in December,” said Jennifer Boland-Masterson, Boeing operations director at MAF, in a statement.
“After we deliver the stage, NASA will transport it on the agency’s Pegasus barge from Michoud to NASA’s Stennis Space Center near Bay St. Louis, Mississippi, for Green Run testing. Our team here at Michoud will continue work with NASA to build, outfit and assemble the core stage for Artemis II, the first mission that will send astronauts to orbit the Moon. Lessons learned and innovations developed in building the first core stage are making the second one progress much faster.”
The RS-25 engines are recycled from NASA’s space shuttles where clusters of three then called Space Shuttle Main Engines or SSMEs powered the orbiters and propelled 135 missions to space.
NASA now has 16 RS-25 engines in inventory. They have been modified and upgraded to power SLS. They were originally built and then refurbished by Aerojet Rocketdyne.
Among the significant upgrades is the new engine controller which functions as the ‘brain’ to command the engines. See our photos.
The RS-25 engines have been ready for installation since Oct. 2017 when they completed qualification testing at Stennis.
The core stage is scheduled to arrive in the Turn Basin at KSC on board the Pegasus Barge on Friday, Sept. 27 and then be offloaded and moved to the Vehicle Assembly Building (VAB) on Monday, Sept. 30.
Media including Space UpClose have been invited to attend. Watch for our on site coverage and photos both days.
Pegasus is NASA’s one of a kind barge used to transport the space vehicle hardware between NASA centers for testing and eventually to the launch site at the Kennedy Space Center in Florida.
The Pegasus has been lengthened to accommodate the SLS core stage which is longer than the Space Shuttle External Tanks it previously shipped from NASA Michoud to NASA KSC.
But SLS is years behind schedule and billions over budget and Boeing has encountered numerous hardware manufacturing problems and difficulties resulting in substantial delays.
NASA originally hoped to launch SLS-1 by the end of 2017 – so the rocket is at least 3 years behind schedule.And I’ve been visiting and documenting progress over the years.
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.