Don't stop me now As preps continue, its looking more likely NASA will fly the Artemis II mission The core stage of NASA's Space Launch System is now integrated with the rocket's twin boosters. Stephen Clark Mar 24, 2025 7:08 pm | 8 The Space Launch System's core stage is seen sandwiched between the rocket's twin solid-fueled boosters inside the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. Credit: NASA/Frank Michaux The Space Launch System's core stage is seen sandwiched between the rocket's twin solid-fueled boosters inside the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. Credit: NASA/Frank Michaux Story textSizeSmallStandardLargeWidth *StandardWideLinksStandardOrange* Subscribers only Learn moreLate Saturday night, technicians at Kennedy Space Center in Florida moved the core stage for NASA's second Space Launch System rocket into position between the vehicle's two solid-fueled boosters.Working inside the iconic 52-story-tall Vehicle Assembly Building, ground teams used heavy-duty cranes to first lift the butterscotch orange core stage from its cradle in the VAB's cavernous transfer aisle, the central passageway between the building's four rocket assembly bays. The cranes then rotated the structure vertically, allowing workers to disconnect one of the cranes connected to the bottom of the rocket.That left the rocket hanging on a 325-ton overhead crane, which would lift it over the transom into the building's northeast high bay. The Boeing-built core stage weighs about 94 tons (85 metric tons), measures about 212 feet (65 meters) tall, and will contain 730,000 gallons of cryogenic propellant at liftoff. It is the single largest element for NASA's Artemis II mission, slated to ferry a crew of astronauts around the far side of the Moon as soon as next year.Finally, ground crews lowered the rocket between the Space Launch System's twin solid rocket boosters already stacked on a mobile launch platform inside High Bay 3, where NASA assembled Space Shuttles and Saturn V rockets for Apollo lunar missions.On Sunday, teams inside the VAB connected the core stage to each booster at forward and aft load-bearing attach points. After completing electrical and data connections, engineers will stack a cone-shaped adapter on top of the core stage, followed by the rocket's upper stage, another adapter ring, and finally the Orion spacecraft that will be home to the four-person Artemis II crew for their 10-day journey through deep space. Four RS-25 engines left over from NASA's Space Shuttle program will power the SLS core stage. Credit: NASA/Frank Michaux Through the motionsThis will be the first crewed flight of NASA's Artemis program, which aims to land astronauts on the lunar south pole and eventually build a sustainable human presence on the Moon, with an eye toward future expeditions to Mars. The program's first crewed lunar landing is penciled in for the Artemis III mission, again using SLS and Orion, but adding a new piece: SpaceX's enormous Starship rocket will be used as a human-rated lunar lander. Artemis II won't land, but it will carry people to the vicinity of the Moon for the first time since 1972.The core stage for Artemis II arrived from its factory in Louisiana last year, and NASA started stacking the SLS solid rocket boosters in November. Other recent accomplishments on the path toward Artemis II include the installation of the Orion spacecraft's solar panels, and closeouts of the craft's service module at Kennedy Space Center with aerodynamic panels that will jettison during launch.As soon as next month, the Orion spacecraft will travel to a different facility at Kennedy for fueling, then to another building to meet its Launch Abort System before moving to the VAB for stacking atop the Space Launch System. For the Artemis I mission, it took around eight months to complete these activities before delivering Orion to the VAB, so it's fair to be skeptical of NASA's target launch date for Artemis II in April 2026, which is already running years behind schedule.However, the slow march toward launch continues. A few months ago, some well-informed people in the space community thought there was a real possibility the Trump administration could quickly cancel NASA's Space Launch System, the high-priced heavy-lifter designed to send astronauts from the Earth to the Moon. The most immediate possibility involved terminating the SLS program before it flies with Artemis II.This possibility appears to have been overcome by circumstances. The rockets most often mentioned as stand-ins for the Space Launch SystemSpaceX's Starship and Blue Origin's New Glennaren't likely to be cleared for crew missions for at least several years. The Orion spacecraft for the Artemis II mission, seen here with its solar arrays installed for flight, just prior to their enclosure inside aerodynamic fairings to protect them during launch. Credit: NASA/Rad Sinyak The fully reusable Starship holds immense long-term promise to be significantly cheaper and more capable than the Space Launch System, but it suffered back-to-back failures to start the year, raising questions about SpaceX's upgraded Starship design, known as "Version 2" or "Block 2." Once SpaceX irons out the design issues, it must prove it can recover and reuse Starships and test the vehicle's in-orbit refueling capabilities. Blue Origin's New Glenn had a successful debut flight in January, but its next flight is likely six or more months away. Neither rocket will be ready to fly people for at least several years.NASA's existing architecture still has a limited shelf life, and the agency will probably have multiple options for transporting astronauts to and from the Moon in the 2030s. A decision on the long-term future of SLS and Orion isn't expected until the Trump administration's nominee for NASA administrator, Jared Isaacman, takes office after confirmation by the Senate.So, what is the plan for SLS?There are different degrees of cancellation options. The most draconian would be an immediate order to stop work on Artemis II preparations. This is looking less likely than it did a few months ago and would come with its own costs. It would cost untold millions of dollars to disassemble and dispose of parts of Artemis II's SLS rocket and Orion spacecraft. Canceling multibillion-dollar contracts with Boeing, Northrop Grumman, and Lockheed Martin would put NASA on the hook for significant termination costs.Of course, these liabilities would be less than the $4.1 billion NASA's inspector general estimates each of the first four Artemis missions will cost. Most of that money has already been spent for Artemis II, but if NASA spends several billion dollars on each Artemis mission, there won't be much money left over to do other cool things.Other options for NASA might be to set a transition point when the Artemis program would move off of the Space Launch System rocket, and perhaps even the Orion spacecraft, and switch to new vehicles. Looking down on the Space Launch System for Artemis II. Credit: NASA/Frank Michaux Another possibility, which seems to be low-hanging fruit for Artemis decision-makers, could be to cancel the development of a larger Exploration Upper Stage for the SLS rocket. If there are a finite number of SLS flights on NASA's schedule, it's difficult to justify the projected $5.7 billion cost of developing the upgraded Block 1B version of the Space Launch System. There are commercial options available to replace the rocket's Boeing-built Exploration Upper Stage, as my colleague Eric Berger aptly described in a feature story last year.For now, it looks like NASA's orange behemoth has a little life left in it. All the hardware for the Artemis II mission has arrived at the launch site in Florida.The Trump administration will release its fiscal year 2026 budget request in the coming weeks. Maybe, then, NASA will also have a permanent administrator, and the veil will lift over the White House's plans for Artemis. Listing image: NASA/Frank Michaux Stephen ClarkSpace ReporterStephen ClarkSpace Reporter Stephen Clark is a space reporter at Ars Technica, covering private space companies and the worlds space agencies. Stephen writes about the nexus of technology, science, policy, and business on and off the planet. 8 Comments