HALO
A FIELD GUIDE TO THE LUNAR GATEWAY
Ten chapters on the small international space station designed for a strange, elegant lunar orbit no crewed station had ever occupied — and on NASA’s 2026 decision to pause it, with hardware partly built and its reuse still being worked out. Status as of 10 October 2026. Scroll to begin.
BEGIN — CHAPTER 01 →Not permanently crewed, and not meant to be
The ISS is always occupied, resupplied every few weeks, and reachable by a rescue vehicle within hours. Gateway was designed for the opposite environment: crews of up to four visiting during Artemis missions [1], then the station left to operate on its own, sometimes for months, far outside Earth’s protective magnetosphere.
That meant designing systems that could diagnose their own faults and work around them, with no possibility of a repair crew launching within days the way the ISS has always allowed.
A one-week loop that costs almost no fuel
Gateway’s chosen path is a near-rectilinear halo orbit — a highly elongated loop around the Moon that swings within about 1,500 km (1,000 miles) of the surface at its closest and out to about 70,000 km at its farthest, completing one orbit roughly every 6.5 days. [1]
It’s a close cousin of the same family of orbits governed by the Lagrange-point physics of the Earth-Moon system — stable enough to hold with very little propellant, while keeping an uninterrupted link to Earth and good coverage of the south pole. [1]
Five planned modules from four providers
Work concentrated on the first two elements, PPE and HALO; neither had flown when NASA announced the pause. [1] [4] Select a component to see its planned role.
Five partners, one small station
Like the ISS before it, Gateway was structured as an international barter — each partner contributing hardware in exchange for crew time and access, rather than cash.
A 60-kilowatt solar-electric powerhouse
The Power and Propulsion Element is a 60-kilowatt solar-electric spacecraft — NASA’s FAQ calls it the most powerful solar-electric spacecraft ever flown, although it has not yet flown — using that power for high-efficiency ion thrusters that would hold Gateway in its orbit with a fraction of the propellant a chemical rocket needs. It was first powered on in 2025. [1] [2]
Built by Lanteris Space Systems in Palo Alto, California (formerly Maxar Space Systems, which won the $375 million contract in May 2019), PPE also carries Gateway’s primary communications and attitude-control systems — everything else on the station depends on it working. [2] [8]
A pressurised cabin built on two continents
The Habitation and Logistics Outpost was to be the first place astronauts actually lived aboard Gateway. Its primary structure was built by Thales Alenia Space in Turin, Italy, and flown to Arizona on 1 April 2025 for outfitting by Northrop Grumman in Gilbert. [3]
Unlike the ISS, which has hosted continuous crews since 2000, HALO was designed for intermittent occupancy — visits timed to Artemis missions, with the station otherwise running unattended. [1]
Outside the magnetosphere, on purpose
Paused in its current form
On 24 March 2026 NASA said it intends to pause Gateway “in its current form” and shift to infrastructure for sustained surface operations — a Moon Base — repurposing applicable equipment and building on partner commitments. [4] It was part of the same reformulation that turned Artemis III into an Earth-orbit lander test and made Artemis IV the first landing. [9]
In April 2026 NASA issued a stop-work order on HALO. Its combined contract value — $1.3 billion when it was converted to a firm fixed price in 2021 — had grown to $1.9 billion, and Northrop Grumman was working to fix corrosion found in 2025 throughout the module’s primary structure. The Inspector General projected that, had work continued, HALO would not have been delivered until July 2031 and Gateway would not have operated before 2032. [5]
Two modules, two different fates
Status of each piece as of 10 October 2026, from NASA and its Inspector General. Decisions on reusing the hardware were not final as of June 2026. [5]
An idea that outlasts its own timeline
Whatever becomes of PPE and HALO specifically, the underlying idea — a durable staging point in deep space, built once and reused for years — is very unlikely to disappear from lunar and Mars planning entirely.
Sources cited throughout this guide
Bracketed numbers in the text above correspond to the sources below.