KENNEDY SPACE CENTER, FL – The 21 story tall core stage pathfinder vehicle for NASA’s Space Launch System (SLS) megarocket arrived at the Kennedy Space Center (KSC) in Florida on the agency’s upgraded Pegasus barge under sunny skies this afternoon, Sept. 27, for about 4 weeks of critical testing and stacking exercises in support of the Artemismoon exploration program aimed at landing US astronauts on the lunar south pole by 2024.
Pegasus and Pathfinder sailed into the Turn Basin at Kennedy about 3 p.m. EDT today after being towed by a pair of ocean-going and river-going tugboats for a nearly 1000-mile and week-long journey from NASA’s Stennis Space Center in Mississippi to KSC, and docked around 3:45 p.m.
Technicians plan to be offload the 212-foot long Pathfinder from the 310-foot-long Pegasus barge on Monday, Sept. 30 and move it a short distance to the iconic Vehicle Assembly Building (VAB) for a month of maneuvering and stacking practice before the first real SLS core stage arrives sometime in mid-2020 for eventual launch on the Artemis 1 mission.
Media including Space UpClose were invited to attend both today and Monday. Watch our on site coverage from today and upcoming next week.
Football field sized Pegasus was towed into Port Canaveral channel and sailed past Jetty Park pier around 7:30 a.m. this morning. It briefly docked at the middle basin where the two ocean-going tugboats were swapped out for two river-going tugboats- named Termite and American.
By 10 a.m. the fleet of ships were on the way and I observed them passing through Canaveral Lock around 10:30 a.m. Friday, Sept 27 after they passed by the SpaceX recovery fleet for Falcon rockets and Crew Dragons.
Thereafter Pegasus and Pathfinder turned north on the Banana River -accompanied by a KSC tracking ship and heading towards inland water ways to KSC Launch Complex 39 and the VAB.
The inland path was dredged decades ago by NASA to open up access to the VAB at the KSC Turn Basin and Press site.
Pegasus followed the same route used by NASA vessels decades earlier to ship Apollo moon rocket stages and Space Shuttle External tanks and solid rocket boosters.
Pegasus is NASA’s one of a kind and football field sized 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 SLS core stage pathfinder is a full-scale mockup test article that is identical to the core stage in shape, size and weight. But it is built from stainless steel and has wire rim replica engine placeholders.
The SLS core stage pathfinder was transported from NASA’s Stennis Space Center in Mississippi where it recently completed fit check testing for the upcoming ‘green run’ test of the first real SLS core stage for the Artemis 1 mission.
NASA will conduct a full duration ‘green run’ engine fire test of the completed core stage at Stennis to fully confirm its readiness for flight on Artemis 1. But that test will require six months of intense work by NASA and contractor teams.
The pathfinder hardware now arrived at KSC will be used by NASA engineers and contractors for the next four week to practice stacking the hardware in the VAB High Bay 3 using the same procedures needed to stack the real hardware for the Artemis I mission.
“The pathfinder, though not actual flight hardware, will provide the SLS program, Exploration Ground Systems (EGS) team with the opportunity to practice stacking maneuvers and certify the new system inside the Vehicle Assembly Building (VAB) High Bay 3 before Artemis flight hardware arrives next year,” say NASA officials.
“Over the next several months, pathfinder will be used to validate ground support equipment and demonstrate how the core stage will be integrated in the VAB – the same process the actual core stage will undergo when being processed for Artemis I.”
The pathfinder exercises will be completed by Oct 31.
The teams will practice rolling the pathfinder off Pegasus and into the VAB. Crane crews will then lift it vertically for placement into High Bay 3 – minus the Mobile Launcher which currently resides atop Launch Complex 39B.
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 SLS-1 core stage will propel the Artemis I mission on the first integrated flight of the SLS rocket and NASA’s Orion deep space human spacecraft to the Moon – as soon as late 2020 but more likely in early 2021.
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.
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.