If NASA sends astronauts back to the moon under the Artemis program, they will take the long run. Rather than being another “footprints and flags” program, the goal is to create permanent infrastructure that will ensure a “sustainable lunar exploration program”. A key element in this plan is the Lunar Gateway, an orbit habitat that astronauts will use to venture to and from the surface.
The first step in setting up the gateway is the use of two critical modules – the outpost for housing and logistics (HALO) and the power and drive element (PSA). According to a recently released update, NASA (along with Maxar Technologies and Busek Co.) recently completed a hot-fire test of the PSA propulsion subsystem – the first of many to ensure the PSA and HALO will be ready to go by 2024.
This propulsion subsystem is a collection of Hall Effect thrusters (also known as an ion motor) that use electromagnetic fields to propel ionized gas through engine nozzles to create thrust. In this case, the motor system is a 6 kilowatt (kW) solar electric propulsion (SEP) concept that includes electronics built by Maxar and a xenon delivery system with four BHT-600 engines built by Busek.
This system is 30% more powerful than any system previously built and flown by Maxar or Busek and is combined with higher-powered Hall-effect thrusters to complete the PSA’s 50 kW SEP system. Robert Curbeam, Senior Vice President, Space Capture at Maxar Technologies said:
“Busek’s BHT-6000 electric thrusters offer high performance capabilities at a competitive price and are ideal for our near-earth and space programs. The SEP systems we are developing for PSA are a fantastic example of innovative commercial technology that leverages a large aviation heritage for NASA programs. We continue to make steady progress in the power and drive element. The next major milestone is the spacecraft preliminary design review, which is scheduled for later this year. “
The hot fire test was funded by NASA’s Space Technology Directorate as part of their Tipping Point program. Every year, the STMD awards grants to commercial partners to promote the development of technologies that enhance commercial space capabilities and benefit future NASA missions.
In 2018, Maxar Technologies – formerly Space Systems / Loral (SSL) – was selected via Tipping Point to develop the Power Processing Unit (PPU) that will power the 6 kW Hall engine. Busek Co. is a long-time NASA partner known for its Hall-effect satellite thruster technology. Previous posts include mini electrospray thrusters for CubeSats and the ST7-DRS thruster system used by the LISA Pathfinder mission.
This recent test consisted of powering up and down the system several times and running various flight-like scenarios to demonstrate whether the system was suitable for operations around the moon. The test, which lasted several weeks, was the first time that the hardware developed by Maxar and Busek was operated as a fully integrated system and was used to validate the dual-mode operation of the SEP up to an output of 6 kW and 600 volts.
Mike Barrett, power and propulsion manager at NASA’s Glenn Research Center, said:
“This is an exciting first step in proving that PSA’s propulsion system meets Gateway requirements. These thrusters will be critical to delivering the first elements of Gateway to lunar orbit and helping us create a dynamic exploration platform over Gateway’s 15 year lifespan. “
Once fully assembled and integrated, the PSA will be the most powerful electric propulsion spacecraft ever flown, maneuvering the gate around the moon. Together with a reusable lunar lander, the gateway will open more lunar surface than ever for exploration. PPE and HALO are currently scheduled to launch together on board a Falcon Heavy in 2024 to prepare for the Artemis III mission.
In addition to HALO, other modules will be added over time, such as the European System for Refueling, Infrastructure and Telecommunications (ESPRIT) and the International Habitation Module (I-HAB). These modules are being developed by ESA and JAXA in collaboration with the French aerospace developer Thales Alenia Space – with additional contributions from NASA and the Canadian Space Agency (CSA).
ESA has signed a contract with Thales Alenia Space to build the ESPRIT module for Gateway, a planned space station in lunar orbit. Photo credit: ESA
These modules will be launched by 2026 or 2027 and integrated into the gateway in lunar orbit. This station will be an important part of NASA’s Artemis program and provide vital support for long-term missions to the lunar surface. It will also enable partnerships with other space agencies (such as ESA, CSA, JAXA and others) that will continue in the tradition of the ISS.
In combination with a reusable lander, a base camp will also be set up on the lunar surface where astronauts can conduct important research under lunar conditions. Last but not least, it will enable crewed missions to Mars in the next ten years. From this point on, it will no longer be a “gateway” to the surface of the moon, but also to places in space.
Further reading: NASA, Maxar Technologies