Lunar missions are running into a navigation wall. Landers heading for the south pole this decade cannot rely on GPS, the Moon has no positioning constellation of its own yet, and the commercial cadence of flights is accelerating faster than the infrastructure meant to guide them. Every recent lunar landing failure has put the same uncomfortable question in front of operators and investors: how does a spacecraft know exactly where it is and which way it is pointed when the signals that anchor terrestrial navigation simply are not there?
Northrop Grumman thinks the answer, at least for the next several years, is hardware that does not need outside help at all. The company has repurposed guidance technology originally built for the James Webb Space Telescope into a commercial product aimed squarely at the emerging lunar economy. Its new inertial measurement unit, the LR-450, was developed as a commercial-grade unit for precise guidance and control of spacecraft, intended to keep them oriented and on course in regions where GPS signals fade to uselessness.
The bet is straightforward. As traffic to the Moon and cislunar space accelerates, satellites and landers need self-contained ways to know where they are pointed and how fast they are turning. Inertial measurement units do that job. Northrop Grumman is wagering that hardware proven on a flagship observatory parked a million miles from Earth will sell well to the next wave of lunar operators.
From a flagship observatory to a commercial product line
The James Webb Space Telescope arrived at the Sun-Earth L2 Lagrange point in January 2022, where it has operated since. Keeping a 21-foot segmented mirror steady enough to resolve features on distant exoplanets demands extreme precision in attitude control. The gyroscopes and pointing electronics built for Webb had to deliver that performance for years without service calls.
Northrop Grumman, which built the spacecraft bus for Webb, has now miniaturized that lineage. The unit is designed to be compact and power-efficient for commercial spacecraft applications. At the core sits a miniature hemispherical resonating gyroscope, which measures rotation by tracking vibrations in a small resonator rather than through spinning mechanical parts.
The GPS problem above low Earth orbit
GPS was engineered for users on or near the surface of the planet. Its satellites sit in medium Earth orbit and beam their signals downward. Spacecraft in low Earth orbit can pick up usable signals by looking sideways across the planet at the constellation, but push past geostationary altitude and the signal geometry collapses. For lunar missions, GPS is effectively absent, and the same gap haunts military assets in higher orbits and any probe heading into deep space.
That void is why agencies are racing to build dedicated lunar navigation infrastructure. The European Space Agency’s Moonlight programme is building a constellation of five lunar satellites, four for navigation and one for communications, with the Lunar Pathfinder relay spacecraft acting as the precursor mission. Those constellations are years from full operation, so until they exist, spacecraft must navigate using what they carry onboard. That is the slot the new inertial measurement unit is built to fill — and it does so by needing no external reference at all. An IMU tracks rotation and acceleration internally and integrates those measurements over time to estimate orientation and trajectory. The catch is drift. Every IMU accumulates error, and the longer a vehicle relies on inertial data without correction from a star tracker, ground signal, or GNSS fix, the larger that error grows.
Hemispherical resonating gyroscopes are prized because they drift slowly. They have no spinning mass to wear out and no fluid-filled rings, which makes them well suited to long-duration missions where servicing is impossible. Webb itself sits roughly four times farther from Earth than the Moon, with no possibility of repair after launch. For a lunar lander making a powered descent, drift tolerance translates directly into landing accuracy. For a relay satellite in a near-rectilinear halo orbit, it determines how long the spacecraft can hold its pointing between ground updates. Vendors who can shave grams and watts off that hardware win design slots on commercial landers where every kilogram costs money.
A crowded but immature market
The lunar services sector has expanded faster than most of its underlying infrastructure. NASA’s Commercial Lunar Payload Services program has put contracts in the hands of multiple American companies, and lander demand has pulled in adjacent suppliers ranging from launch providers like Firefly Aerospace to communications operators planning relay constellations.
Navigation hardware is one of the less visible pieces of that supply chain, but it is one of the most consequential. A landing failure traced to a guidance fault can end a company. The industry has responded by tightening requirements on inertial sensors and star trackers.
Northrop Grumman’s pitch to that market leans on heritage. The same engineering lineage that holds Webb’s mirrors steady is being offered, in a smaller package, to commercial operators who cannot afford the development cost of a flagship-grade IMU.
Modularity as a selling point
The unit is designed as a modular product suitable for satellites from Earth orbit out to deep space. That breadth matters. A vendor selling a single product across multiple mission classes can amortize development costs and offer customers a known quantity rather than a custom build.
The unit is intended to support complementary navigation architectures designed to reduce dependence on GPS. The approach does not promise replacement of satellite navigation, but rather a layered approach in which onboard inertial sensing fills the gaps that external signals cannot reach.
That layered model is where lunar navigation is heading. Future spacecraft are likely to combine inertial data with star trackers, ranging from Earth-based stations, optical landmark recognition near the surface, and signals from whatever lunar GNSS constellation eventually emerges. Each input compensates for the weaknesses of the others.
The bigger industrial pattern
Northrop Grumman’s move follows a familiar arc in aerospace. Hardware developed for a high-stakes government mission gets refined, miniaturized, and sold into commercial channels once the technology matures. The company has run this play before in other domains, including missile defense systems where flight-proven subsystems migrate between programs.
What is new is the destination market. Lunar operations were not a meaningful commercial category a decade ago. They are now. The companies that supplied parts for Apollo or for science flagships are repositioning to sell those same competencies to a younger set of customers planning recurring missions rather than one-off expeditions.
The stakes extend well past which vendor wins which contract. The lunar economy that investors and agencies have been sketching out — water prospecting at the south pole, cargo delivery for Artemis, science payloads riding commercial landers, eventually crewed surface infrastructure — assumes spacecraft can reliably arrive where they intend to. Every guidance failure that scatters hardware across the regolith raises insurance premiums, lengthens schedules, and chills the capital that the sector needs to keep flying. Navigation is not a glamorous line item, but it is the one that decides whether commercial lunar activity becomes a routine business or stays a string of expensive demonstrations.
For now, a piece of guidance technology that helps a telescope at L2 stare into the early universe is being repackaged to help landers find their way to the lunar south pole. The destinations could not be more different. The underlying problem — knowing exactly which way a spacecraft is pointed — is the same, and solving it cheaply and repeatedly is the precondition for everything else the industry has promised.
