NASA’s Exploration Ground Systems (EGS) program and prime test and operations contractor (TOSC) Jacobs are working at the Kennedy Space Center (KSC) to position Artemis 1 Orion and Space Launch System (SLS) hardware to be ready for final assembly ahead of the arrival of the SLS Core Stage in the late-April time-frame. With the final major Core Stage test completed, the SLS Boosters are stacked in the Vehicle Assembly Building (VAB) and fueling of the Orion spacecraft was expected to begin.
EGS and Jacobs are also working to align the schedules of cubesat payloads and the Interim Cryogenic Propulsion Stage (ICPS) so they can be ready for vehicle integration when their turn arrives for stacking. EGS is looking at ten months of work to get ready for Artemis 1 once the Core Stage arrives, which would put the current launch forecast towards the end of the first quarter of 2022.
Orion, ICPS preparing for propellant loading
Now that the major SLS Core Stage Green Run tests are finally complete, more attention is turning to KSC in Florida where EGS and Jacobs are already processing the rest of the Artemis 1 vehicle for the first flight of all the Exploration Systems Development (ESD) division programs. While an Orion crew module flew the Exploration Flight Test-1 mission in late 2014 on a Delta IV Heavy launch vehicle, all the other ground and vehicle elements from the Mobile Launcher to the Orion Service Module to SLS will make their debut on Artemis 1.
The Core Stage Hot-Fire on March 18 at the Stennis Space Center was the final major standalone development test; now that it has been performed, stage prime contractor Boeing and RS-25 engine prime contractor Aerojet Rocketdyne are performing inspections and refurbishment required before transportation from Stennis to the Kennedy Space Center launch site. About 30 days was planned after the test-firing to get the Core Stage ready to depart Stennis, and NASA is hoping to see it on dock at the Launch Complex 39 Turn Basin around April 27.
Once the Core Stage is at KSC, what remains to get ready for Artemis 1 is the first-time full assembly and integration with the launch infrastructure there. There’s still some uncertainty when Artemis 1 will be ready to go.
“We know the flow once we get the Core Stage but at this point there is still work to be defined, traveled work, that will have to be performed,” Cliff Lanham, NASA Senior Vehicle Operations manager for EGS at KSC, said. “So what I would tell you is that from that standpoint we fully expect it to take, once the Core Stage arrives on dock, ten months to get everything completed and to get the vehicle to launch ready.”

Credit: NASA/Kim Shiflett.
(Photo Caption: The Artemis 1 Orion spacecraft in the Multi-Payload Processing Facility (MPPF). The uncrewed Orion will orbit the Moon during the mission and it is being loaded with all the commodities needed for the mission, from ammonia to nitrogen to helium to hypergolic propellants.)
The testing-heavy schedule will be periodically refined, and NASA has not officially ruled out a launch in 2021, but a late-April, early-May arrival of the Core Stage at KSC and a 10 month estimate from there to Artemis 1 launch readiness projects out to the February-March, 2022 timeframe.
All the other major Artemis 1 hardware elements are already at KSC and have been formally turned over to EGS for launch processing. Both the Orion spacecraft that will orbit the Moon on Artemis 1 and the SLS Boosters have started that work.
After Lockheed Martin delivered the Artemis 1 Orion to EGS, the spacecraft was transferred from the Armstrong Operations & Checkout (O&C) Building at KSC to the Multi-Payload Processing Facility (MPPF) on January 16. Work on the spacecraft to load its flight commodities was juggled due to delays in the Core Stage Green Run schedule, and the sequence is now ordered so that the most life-limited items are serviced at the end.
“For example, the CM (Crew Module) helium tanks have a limited life of a little over a year,” Marcos Pena, NASA Spacecraft Element Operations manager for EGS at KSC, said. “So given that the Core Stage is completing its testing at Stennis, we don’t want to go ahead and start those clocks prematurely, so we have switched the operations such that we’re servicing the commodities that don’t have limited life associated with them [first].”
Pena noted that so far the Service Module (SM) helium and nitrogen tanks in Orion have been loaded; Lockheed Martin did the SM nitrogen servicing in the O&C Building before the handover to EGS. The test team then serviced the CM ammonia to do a functional check of the thermal control system; after the test, the ammonia was then drained from the system.
“There’s an ammonia functional check – which, basically, we load it to the flight level, it’s about 80 pounds, and then we power up all the systems on the CM and the SM and verify that we can reach these various [temperature] set points,” Pena explained.

Credit: NASA/Kim Shiflett.
(Photo Caption: The Orion spacecraft was covered up for its transport from the Armstrong O&C Building to the MPPF on January 16. Prime contractor Lockheed Martin formally turned over the fully-assembled Orion to EGS to begin its launch processing for Artemis 1.)
The team is also performing fit checks of equipment inside the Crew Module. “We’ve been trying to take advantage of when we’re not doing a hazardous operation in the MPPF and we have the hatch open, we’re trying to do fit checks,” Pena said. The equipment cage of one experiment has already been fit checked, and in April the plan is to do a test install of a crew seat with a suited mannequin.
“One of the payloads that we’re flying on Artemis 1 is a suited mannequin with radiation dosimeters, and the Orion suit that the Artemis 2 crew would wear,” Pena noted. “We’re going to plan on doing a fit check while we’re at the MPPF not doing hazardous ops. That fit check is going to be done some time in the early to mid-April time-frame.”
The mannequin will be strapped to a seat that will be removed once Orion lands at the completion of Artemis 1 and readied to carry a human passenger on the Artemis 2 mission.
“Actually today we’re in the middle of fit checking the lightning monitoring system inside the Crew Module,” Pena said during the March 16 interview. “We need that lightning monitoring system when we go out to the pad. That will help us have ground truth on whether the vehicle has had any lightning strikes or anything like that.”
In the days before the critical Core Stage test on March 18, the spacecraft offline operations team got ready to start loading the hypergolic propellant commodities onboard the SM. “What we’re going to get into next here between now and mid-May is first is the SM oxidizer loading. There’s about 12,000 pounds of nitrogen tetroxide that we’re going to be loading,” Pena said.
At the time of the interview on March 16, Pena noted that the offline operations team was getting set up to begin the hazardous hypergolic loading. “Today, we’re actually working on the connections to the vehicle between our oxidizer servicing GSE (Ground Support Equipment) and the flight interfaces on the CMA (Crew Module Adapter). And the plan is to do all those connections here in the next few days and be ready to perform the actual flight load next week,” he said.
25.5 MILLION POUNDS
The weight which has been placed on top of Crawler Transporter 2 as it makes passes down the crawlerway in preparation for @NASA_SLS and the launch of #Artemis 1. This is the heaviest weight that has ever been placed on the crawlerway at @NASAKennedy. pic.twitter.com/WZvC1ROCY1
— NASA's Exploration Ground Systems (@NASAGroundSys) March 19, 2021
“Once we complete the oxidizer servicing, we’ll move over onto the MMH (monomethyl hydrazine) servicing on the SM. So we’ll load the fuel on the SM, 8,000 thousand pounds of that, and then the next thing that we’re going to take up after that is doing the actual flight load of the ammonia that we deferred until later in the flow.”
“Immediately after that, we have to do the helium servicing of the CM,” Pena added. “[That] could be extended with waivers, but again the goal was to put that as late in the flow as possible. And then the final thing that we would do is the CM fuel servicing, the hydrazine, and then after that we’re ready to roll out of the MPPF over to the LASF (Launch Abort System Facility).”
The LASF is where the Orion’s Launch Abort System and ogive fairings will be installed before it is then transported to the VAB for stacking.
Orion was joined in the MPPF by the ICPS upper stage of the SLS rocket on February 18. The stage will eventually need its own hydrazine servicing to power its reaction control system (RCS), but the ICPS was moved to the MPPF to clear space out of other facilities. “That was not the original plan,” Pena said. “That was an audible that we made, and it took some work to get both SLS and Orion on board.”
“What drove that decision was that the ICPS went back to ULA (United Launch Alliance) for a couple of months. They were doing some rework associated with some issues they had with the harnesses, and at some point they needed to make room so that they could continue their operations.”
“They essentially needed to get it off their hands and we needed to take ownership of it, and we did that by sending it to the SSPF, the Space Station Processing Facility,” Pena added. “The SSPF [is] getting increased demand for using their high bays, so we needed to move it out of the SSPF as well.”