SLS Upper Stage set to take up residence in the former home of ISS modules

by Chris Bergin

The Interim Cryogenic Propulsion Stage (ICPS) is now deep into its latest phase of processing, as it prepares to be housed in the Space Station Processing Facility (SSPF) – a facility once packed with modules waiting for their ride on Shuttles to make up the elements of the International Space Station (ISS). The ICPS will be the Upper Stage for the maiden flight of the Space Launch System (SLS).

The ICPS will only have a short lifetime with SLS, as the program aims to “swiftly” move to the more powerful Exploration Upper Stage (EUS) that will be the workhorse Upper Stage for SLS throughout the 2020s.

However, for the ICPS, the mission with SLS is only a change of call signs for this veteran unit, with years of previous – and future service – with the United Launch Alliance (ULA) Delta IV rocket fleet.

The official plan has revolved around moving to the EUS by the second or third flight of SLS, pending the readiness of the new EUS. The initial plan was to human rate another ICPS for EM-2, but NASA wants to bring the EUS online by the second SLS flight.

Based on the schedule slips for SLS – and the large gap between EM-1 and EM-2 – the plan is to revamp the Mobile Launcher umbilicals to cater for the Block 1B SLS after EM-1 (Exploration Mission-1) launches.

The EM-1 upper stage – which is effectively a ‘regular’ Delta Cryogenic Second Stage (DCSS) – was shipped from the ULA facility in Decatur, Alabama aboard the Mariner barge earlier this year, arriving at the Cape in March.

It is currently housed in ULA’s Horizontal Integration Facility (HIF) to begin processing for launch at the ULA Delta Operations Center. That work is now drawing to a close.

The next move will see it take a short journey to the SSPF, prior to a formal handover between ULA and NASA.

“The Operations Planning team, specifically the Spacecraft Offline Operations (SOO) team are supporting the delivery of the Interim Cryogenic Propulsion Stage (ICPS) to the Space Station Processing Facility (SSPF). It is expected to be accelerated ten days from predicted August 1, 2017 to July 21, 2017,” noted a Ground Systems Development and Operations (GSDO) update.

The SSPF is a three story structure containing 42,455 sq meters (457,000 sq ft) of offices, laboratories, and processing areas. It is located on NASA Causeway immediately east of the O&C (Operations & Checkout) Building.

The facility houses bays that were used for horizontal processing of components for the International Space Station and other Space Shuttle Payloads. With the payloads since launched on the now-retired Space Shuttle fleet – resulting in the impressive orbital outpost that is now into its utilization phase – the facility is almost empty of space hardware.

Prelaunch activities that took place in the SSPF included receipt, handling, and assembly of space station hardware, testing of experiments for proper configuration, and verification of critical systems and system interfaces. As such it makes it the perfect home for the ICPS ahead of its launch with the first SLS rocket.

The ICPS won’t be officially handed over (or “turned over”) until some weeks after the ICPS arrives in the SSPF, allowing the Stage’s caretakers from ULA to continue to look after the ICPS and provide guidance to its new engineers.

“Preparations are underway and include a contractor letter of direction for host role in the early weeks with the formal DD250 turnover to follow, hurricane plan development and approval, SSPF facility panel sampling,” added the GSDO update.

“(The) plan is for United Launch Alliance (ULA) access to perform monitoring and maintenance until formal turnover, and a likely transporter demonstration at the SSPF. All of these are to be addressed by the planned readiness review scheduled for July 19, 2017, at the Operations Processing Project Review (OPPR).”

The eventual destination for the ICPS will be the Vehicle Assembly Building (VAB) at KSC, in preparation for mating atop the SLS stack.

The stack will be integrated while sitting on the Mobile Launcher, which will provide the lifeblood of electrical and fluid support, along with the all-important prop loading whilst at the pad.

That connection between the ML and the ICPS will be the Interim Cryogenic Propulsive Stage Umbilical (ICPSU) will be a T-0 umbilical.

While some umbilicals have already been installed onto the ML, the ICPSU is expected to be connected in September to October timeframe – well ahead of the timeframe the first SLS is scheduled to be mated with the ML in the VAB.

(Images: NASA, ULA and L2 Orbital ATK and L2)

(L2 is – as it has been for the past several years – providing full exclusive SLS and Exploration Planning coverage. To join L2, click here: //

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