Gateway elements start systems integration as NASA plans launch date

The two key elements that will form the initial capability of NASA’s Gateway lunar space station are making steady progress toward launch as systems integration activities ramp up. The Power and Propulsion Element (PPE) and Habitation and Logistics Outpost (HALO) are being constructed in different parts of the world, with plans to launch them together as the co-manifested vehicle (CMV) on a future Falcon Heavy rocket.

After several years of development and manufacturing, the PPE structural assembly is complete, allowing Maxar Technologies to begin installing crucial propulsion system components. A pair of bipropellant tanks and two Xenon composite overwrapped pressure vessels (COPVs) are slated for installation this year, supplying the PPE’s advanced solar electric propulsion (SEP) thrusters.

These SEP thrusters from Aerojet Rocketdyne and Busek have been a critical pacing item for the PPE. The Aerojet thrusters recently completed vibration testing and will undergo further environmental qualification in the coming months. NASA expects the first of three flight thrusters to be delivered to Maxar early next year for integration onto the PPE spacecraft.

Meanwhile, the HALO module’s structural assembly was finalized at Thales Alenia Space’s facility in Italy last fall. After successful stress testing, the structure is scheduled to be shipped to Northrop Grumman’s facilities in Arizona later this year. There, fluid tubing, wiring harnesses, and various subsystems will be installed inside the pressurized volume that will provide living quarters for Artemis crews visiting the Gateway.

Current section: Initial Capability Hardware Integration Underway

With hardware production and assembly progressing well, NASA is also conducting higher-level design reviews in preparation for the CMV’s eventual integration as a single spacecraft. The PPE completed its standalone critical design review (CDR) in March, while the HALO CDR wrapped up in June 2023. An integrated CMV CDR is targeted for the second half of 2024.

Once the PPE and HALO elements are mated together, the CMV will launch aboard a Falcon Heavy on a trajectory to a highly elliptical Earth orbit. From there, the PPE’s SEP system will spiral out over the course of about a year to insert the Gateway into a Near Rectilinear Halo Orbit (NRHO) around the Moon.

While NASA previously aimed for an October 2025 launch date, that target has been pushed back due to various schedule delays. A new official launch date has not been set, but the agency’s Fiscal Year 2025 budget documents provided a “conservative” baseline commitment of December 2027 for “a joint confidence level of 70 percent”. However, NASA stated they still intend to pursue “a more aggressive schedule” than that later projection.

With critical design reviews completed and hardware manufacturing well underway, the two key elements of the Gateway’s initial configuration are transitioning into the systems integration phase. At Maxar Technologies’ facilities, technicians are ready to begin installing the Power and Propulsion Element’s (PPE) propellant tanks and advanced solar electric propulsion (SEP) thrusters.

Two pairs of tanks – one set carrying conventional bipropellants and another containing Xenon for the SEP system – have been delivered to Maxar and are being prepped for installation onto the PPE structure. The Xenon tanks will feed the vehicle’s four Busek BHT-6000 thrusters and three larger Aerojet Rocketdyne Advanced Electric Propulsion System (AEPS) thrusters, providing the primary propulsion for Gateway operations.

These critical AEPS thrusters have undergone a rigorous testing campaign, successfully completing vibration, shock, and thermal vacuum qualification ahead of delivery to Maxar early next year. The first of three flight units is expected to be integrated with the PPE structure in the coming months.

In parallel, the Habitation and Logistics Outpost (HALO) module’s primary structure has completed assembly at Thales Alenia Space in Italy. Following successful structural testing, HALO will be shipped to Northrop Grumman’s Arizona facility later this year, where outfitting will begin. Fluid lines, wiring harnesses, and critical life support systems will be integrated within the pressurized volume to support future Artemis crew visits.