United Launch Alliance (ULA) delivered the last-ever Space Launch System (SLS) Interim Cryogenic Propulsion Stage (ICPS) from its Decatur, Alabama, factory to Cape Canaveral Space Force Station (CCSFS) in early August for eventual use on the Artemis III lunar landing mission. ICPS-3 was also the last Delta hardware to depart Decatur and can support NASA’s third and final launch of the SLS Block 1 rocket before it’s upgraded to the Block 1B configuration starting on Artemis IV.
The SLS in-space stage will remain mostly in storage at ULA’s CCSFS facilities until NASA is able to fly Artemis III; the mission is aspirationally targeted for the top of 2025 but will not be expected until 2026 on the earliest and will possibly fly later than that. Within the meantime, ULA and SLS teams will make final preparations for ICPS-2 to be stacked for the Artemis II circumlunar test flight next 12 months; that stage is fully outfitted and able to be formally turned over from ULA when NASA Exploration Ground Systems (EGS) needs it.
ICPS-3 delivered to CCSFS from Decatur plant
ULA’s seagoing cargo ship, R/S RocketShip, arrived at Cape Canaveral in early August, where the ICPS stage was offloaded still inside its shipping container and brought to the corporate’s Horizontal Integration Facility (HIF). “That’s the large constructing that is correct down the road from their Delta pad, they process mostly Delta hardware in there,” Chris Calfee, NASA SLS deputy manager for the Spacecraft/Payload Integration and Evolution (SPIE) office, said in a recent interview with NSF.
“So, we’ll stage the ICPS there, it is going to stay within the horizontal position. It’ll allow us to really barbeque roll it and do inspections and people varieties of things if we’d like to, but it surely’ll stay there until we’re able to take it down the road to ULA’s Delta Ops Center, we call that the DOC.”
With the second ICPS stage currently in storage on the DOC, ICPS-3 will remain within the HIF until next 12 months. “Every ICPS has been staged there, ICPS-1 was staged there, [and ICPS-]2 was staged there before it went to the DOC,” Calfee noted. “Let’s say ULA has a knowledge statement on a Delta flight and even an Atlas flight that may have cross-fleet components they usually say, ‘Hey we wish to get a heads up on this component,’ we’ve actually pulled the component off of the stage within the HIF.”
“We don’t plan to do anything, but it surely type of depends upon if something comes up with a cross-fleet issue or another issue where we wish to do an inspection. You may’t do testing, but you’ll be able to put scaffolding up and take away a component if it’s essential.”
![](https://www.nasaspaceflight.com/wp-content/uploads/2023/08/ICPS-3-2022-ULA-Composite.jpg)
Major ICPS-3 elements in production in 2022, the liquid hydrogen tank on the left and mid-body structures on the suitable. Credit: United Launch Alliance.
The Interim Cryogenic Propulsion Stage is used as an in-space stage within the SLS Block 1 vehicle design to move payloads out of low Earth orbits. The ICPS is a detailed cousin to the Delta Cryogenic Second Stage (DCSS) used on the soon-to-be-retired Delta IV vehicle, with the key differences being a rather longer liquid hydrogen tank, an additional hydrazine bottle for the stage’s attitude control system, and Orion-specific interfaces, since NASA’s crewed spacecraft is the only primary payload that ICPS and SLS Block 1 will fly.
ICPS-3 can be prone to be the last Delta IV stage to fly, and Calfee said it is going to stay stored within the HIF until after the last planned Delta IV flight hardware is tested and checked out within the DOC next 12 months. “At once, the ICPS-3 [is scheduled] to enter the DOC in spring of 2024,” he said.
“There’s a test cell in there where we’ll do final testing and checkout, run roughly 20 different tests on the stage before we do final acceptance and go into storage. ULA has one final Delta DCSS stage that may go into that cell before us, it flies on a mission called NROL-70, which flies middle of next 12 months I imagine, it’s the last Delta IV Heavy flight.”
“So ICPS-3 will go into the test cell after that [NROL-70] stage moves out,” Calfee added. NASA continues to focus on December 2025 for the Artemis III launch, and Calfee said that the EGS need date can be the spring of 2025. Once EGS receives the stage from ULA, it is going to be moved to the Multi-Payload Processing Facility (MPPF) within the nearby industrial area of Kennedy Space Center (KSC) where the attitude control system hydrazine bottles will likely be loaded for flight before the stage is then transported to the Vehicle Assembly Constructing (VAB) to be stacked with SLS.
ICPS-2 stage outfitted and checked out for flight
ICPS-3 will follow the identical path for Artemis III that ICPS-2 is taking for Artemis II. The stage that may help send the primary astronauts to the Moon in over 50 years is now prepared for the Artemis II launch campaign when it begins next 12 months.
ICPS-2 was originally delivered to Cape Canaveral two years ago in the summertime of 2021; this spring, ULA moved it from the HIF to the DOC to get it ready for Artemis II. “It’s actually complete within the DOC,” Calfee noted.
“It had been in there since we rolled it down the road from the HIF into the DOC. All that testing is complete, it just wrapped up a few weeks ago and the stage was moved from that test cell, down the transfer aisle, into its storage cell.”
![](https://www.nasaspaceflight.com/wp-content/uploads/2023/08/icps2_toDOC3.resize.jpg)
Credit: United Launch Alliance.
After the stage was moved into the test and checkout cell within the DOC, the nozzle extension for the RL10 engine and flight computers for the stage were installed; then, the stage went through a series of tests.
“We do avionics testing, now we have a version of the flight software that we exercise the system with,” Calfee said. “The fundamental testing that we do there, probably the most critical test, is we actually extend the RL10 nozzle. The RL10 on the ICPS is an extendable nozzle, it’s stowed in-flight and it extends right before it fires.”
“We actually do several tests of that nozzle extension, where we extend all of it the best way down. It’s a mechanical test within the DOC after which we slew the engine, backwards and forwards, pitch and yaw, all those angles to make sure that it’s functioning properly.”
“It’s called the NEDS (nozzle extension and deployment system), [it’s] added to the stage within the DOC test cell,” he added. The ICPS flight computer takes over control of the flight after separation from the SLS Core Stage and the avionics are crew-rated for Artemis II.
“There’s a number of select avionics components,” Calfee explained. “The INCA (Inertial Navigation Control Assembly), which is our flight computer; [the stage] is shipped from Decatur without that, so we put a test INCA within the DOC for testing.”
“For Artemis II now we have what known as the emergency detection system. The emergency detection system will likely be used to predict a catastrophic scenario the ICPS can be experiencing on ascent or during in-space operations, which might essentially send a signal to the crew to say ‘Hey, we’re having a foul day, get off.’”
“That’s one in all the important thing differences between [Artemis I and Artemis II], and that component will not be on there after we ship it from Decatur either, so those are your three primary components which can be [installed], the 2 avionics boxes, the INCA and the emergency detection system, and the nozzle extension.”
![](https://www.nasaspaceflight.com/wp-content/uploads/2023/08/ICPS-2-DOC-ULA-Composite.jpg)
Credit: United Launch Alliance.
One among the crew-rating modifications evaluated for ICPS was adding some shielding to scale back the chance of micrometeoroid and orbital debris (MMOD) impacts; nonetheless, Calfee noted that concept turned out to be more trouble than it was value. “We checked out concepts for beefing up a number of the components particularly areas that were probably the most suspect to strikes with shielding and people varieties of things and determined that it just wasn’t feasible, that there would likely be unintended consequences, and really add risk as a substitute of reducing the chance of a catastrophic micrometeoroid strike,” he said.
“In order that risk will actually be the identical for Artemis II and III. Now the trajectory could be very different that we fly for Artemis II and III, so we’ll fly a trajectory to attenuate the chance of a strike.” For instance, all three SLS Block 1 missions using the ICPS plan to fly just one revolution of Earth — the primary one — throughout the range of orbital altitudes that carry the very best calculated risks of MMOD strikes.
Also installed on ICPS-2 on the Delta Operations Center was a rendezvous goal that will likely be utilized by the Artemis II flight crew as a component of an Orion proximity operations and handling qualities demonstration on the primary day of the mission. The centerline goal is one in all two that will likely be utilized by the crew in approaches to the stage and its still-mated launch adapters.
When Orion separates from ICPS, it leaves the Spacecraft Adapter cone and Orion Stage Adapter with the stage. One other centerline goal will likely be installed on the diaphragm of the OSA that plans call for the crew to make use of for its first close approach. Later within the proximity operations demonstration, the ICPS will maneuver in order that the second goal that’s attached to the side of the stage structure faces Orion for one more close approach manually flown by the crew.
Calfee noted that the storage cell within the DOC is something that NASA funded to convert for SLS. “The Delta Operations Center has 4 test cells in it, just one is lively,” he said. “We actually funded a storage cell; it was a cell that ULA had mothballed.”
“Once we decided we desired to fly two additional ICPS-es a number of years back, we predicted that we would wish some storage capability, so we converted one in all those test cells right into a storage cell. That’s where ICPS-2 is now, is in that storage cell.”
Eventually, ICPS-3 will even find yourself in that storage cell when it’s finished and waiting to get the decision from EGS that it’s time for Artemis III stacking.
![](https://www.nasaspaceflight.com/wp-content/uploads/2023/08/LVSA-2-June-2023.jpg)
The finished Launch Vehicle Stage Adapter (LVSA) for Artemis II is moved to a storage location at Marshall Space Flight Center (MSFC) in June. The LVSA will connect the ICPS to the SLS Core Stage. Credit: NASA.
For now, ICPS-2 is waiting to get that decision for Artemis II first. “Our goal launch date for Artemis II is late calendar 12 months 2024, we do have a partnering agreement with EGS on transfer of ICPS-2 and it’s within the spring timeframe of 2024,” Calfee said.
When the time comes, ICPS-2 will likely be moved using the canister that the primary ICPS sat in for thus much time. “That canister known as the VTF, the vertical transport fixture,” Calfee noted.
“That’s unique GSE only for Artemis and the ICPS. We use that to move it from the DOC over to EGS; the primary stop for the ICPS is on the MPPF, we load our hydrazine bottles there for [the attitude control] system after which we use the VTF to move it into the VAB.”
LVSA, OSA status for Artemis II and III
The SPIE element throughout the SLS program is responsible partly for managing all of the pieces of the Integrated Spacecraft and Payload Element (ISPE) of the launch vehicle. For the initial Block 1 vehicle configuration, that features not only the ICPS, however the two adapters that connect the SLS stages and Orion.
The Launch Vehicle Stage Adapter (LVSA) connects the Core Stage and ICPS; it encloses a lot of the stage, including the RL10 engine. SLS can be liable for the Orion Stage Adapter (OSA) that connects Orion to ICPS.
Work to finish production of the Block 1 adapters for Artemis II and III is currently in progress on the Marshall Space Flight Center (MSFC) in Huntsville, Alabama. “They’ve switched buildings within the last month, so there’s been some pictures of some transfers,” Calfee noted.
![](https://www.nasaspaceflight.com/wp-content/uploads/2023/08/LVSA-3-July-2023.jpg)
LVSA-3 is moved from a thermal protection system application facility to a final outfitting facility at MSFC in July. Credit: NASA.
“LVSA-2 is totally finished, it’s in storage here at Marshall Space Flight Center in Constructing 4708. It’s able to ship at any time when EGS needs it. We do have an agreed-to tentative date that it is going to ride the Pegasus barge all the way down to the Cape from Marshall. It’s early spring or late winter so I need to say a February/March timeframe, that’s our planned barge date.”
The LVSA for Artemis III has now taken the spot that LVSA-2 vacated. “LVSA-3 moved from where they were doing the TPS (thermal protection system) application,” Calfee said. “[It] moved just a few weeks ago into Constructing 4649, which is where LVSA-2 moved out of.”
“What we’ll do there’s final integration of specifically the frangible joint and the pneumatic actuation system, which is the separation hardware that gives the separation of ICPS from LVSA,” he added. “That is definitely ULA-provided hardware, so ULA provides the hardware to the federal government, we offer the hardware to [LVSA prime contractor] Teledyne Brown, and Teledyne Brown makes that integration of the [separation] system to the highest of the LVSA. That’s ongoing as we speak.”
The OSA for Artemis II can be nearing completion and readiness for delivery to Florida. “We’re in final assembly there,” Calfee said. “We got direction – I suppose it was a few years ago – to accommodate secondary payloads on Artemis II. In the event you remember for Artemis II, the unique baseline was it was not going to wish secondary payloads.”
“That was reversed some time back and people secondary payloads are mounted within the OSA. So, we’re doing the ultimate integration of that bracketry [and] an avionics unit that controls the deployment of those secondary payloads.”
“That’s ongoing without delay, but we’re forecasting that to be complete in October of this 12 months after which OSA-2 will go into storage,” he added. Eventually, the OSA will likely be shipped to Kennedy Space Center on NASA’s Super Guppy cargo aircraft. “It might be in regards to the same timeframe because the [LVSA], which can be spring of 2024,” Calfee said.
Speaking in regards to the OSA for Artemis III, Calfee noted: “OSA-3 is definitely sitting in the identical room as OSA-2, after all it lags behind so far as production goes there.”
“It has a diaphragm which protects the quantity from environments above it and from Orion,” he noted. “That diaphragm is delivered from an organization called Janicki [Industries] in Washington state, that’s the following step for OSA-3.”
SPIE supporting development, training for Orion and Flight Operations Directorate
Along with the production of the flight stage and connector hardware for Artemis II and III, Calfee noted that the element also provides data products and evaluation to support the Orion program and the Flight Operations Directorate (FOD) on the Johnson Space Center in Houston, Texas.
“One among the things that is exclusive to SPIE and specifically to ICPS is that this support to Orion and FOD,” he said. “Orion for his or her flight software development and FOD for training the crew.”
![](https://www.nasaspaceflight.com/wp-content/uploads/2023/08/SLS-Block-1-ISPE-Elements.jpg)
Credit: NASA.
“We support [FOD] with various scenarios of in-space anomalies so that they can train the crew and their console folks down on the MCC (Mission Control Center) for those potential scenarios. Not one of the other SLS elements participate like that with Orion and FOD.”
“To me that’s exciting,” he added. “We discuss this on a regular basis; it’s been a challenge for us.”
“It’s been a challenge to supply the variety of products that FOD and Orion need from us, but to have the option to work with those programs, to me, is a tremendous opportunity, in order that is something that’s much more vital now with crew on Artemis II and Artemis III. We provided somewhat little bit of those sorts of products for Artemis I but not near the number that we’re providing now.”
They will even be supporting the upcoming flight evaluation cycle for Artemis II, where the launch periods that we became accustomed to for Artemis I in 2022 are calculated. “We undergo a trajectory assessment process with ULA and with the SLS Level II vehicle management team,” Calfee explained.
“The primary phase of that process known as the TFA, trajectory feasibility assessment, that’s essentially ‘Hey look, this trajectory will work, we all know this trajectory will work.’ After which it evolves into PMA, preliminary mission assessment, where you dig down into those trajectories to ensure that they may work, any nuances, after which the period where you do those launch period assessments known as the FMA, the ultimate mission assessment.
“We’ve accomplished the second phase, we’ve just accomplished PMA,” he added. “Our flight software is nearing qualification and completion, to where we’ll declare our flight software as qualified, after which we’ll enter that [FMA] phase.”
“That’s scheduled for fall of this 12 months, the beginning [of] the ultimate phase.”