NASA Navigation Experiment Shows Promise for Planetary Landings

Meta Title: NASA SPLICE Navigation Test Could Improve Future Moon Landings
Meta Description: NASA’s SPLICE navigation experiment used a drone to simulate lunar landing maneuvers, testing autonomous hazard detection and precision guidance technologies for future planetary missions.
URL Slug: nasa-splice-navigation-experiment-planetary-landings
Excerpt: NASA has tested autonomous landing technology designed to help spacecraft identify safe touchdown areas on the Moon and other worlds. The SPLICE experiment, flown on a drone in a terrestrial simulation, combines navigation, terrain analysis, and precision guidance methods that could reduce landing risks for future robotic and crewed missions.

## NASA Tests Autonomous Navigation for Safer Planetary Landings

NASA has reported a successful terrestrial flight test of technology intended to help future spacecraft navigate autonomously toward safer landing sites on the Moon and other planetary bodies.

According to the agency’s announcement, an Alta-X drone carrying NASA’s Safe and Precise Landing – Integrated Capabilities Evolution payload, known as SPLICE, completed simulated lunar descent and landing maneuvers on August 27. The test was conducted at NASA’s Armstrong Flight Research Center in California.

The key point is that this was not a Moon landing and did not involve a spacecraft operating in lunar conditions. Instead, NASA used a drone as a practical flight platform to test guidance, navigation, and control capabilities in a realistic moving environment. The experiment is part of a broader effort to make future landers less dependent on constant ground-based direction during the final stages of descent.

That matters because landing on the Moon remains one of the most difficult tasks in space exploration. A spacecraft must reach a precise destination while traveling at high speed, with limited fuel, delayed communications, uncertain terrain conditions, and no ability to use GPS in the way aircraft and cars do on Earth.

## What Is SPLICE?

SPLICE stands for **Safe and Precise Landing – Integrated Capabilities Evolution**. It is NASA’s effort to mature a group of technologies that could enable landers to recognize hazardous terrain, determine where they are relative to a target, and guide themselves to a suitable touchdown location.

The system is designed around a simple but demanding goal: help a vehicle avoid landing on unsafe terrain.

On the Moon, a seemingly flat region viewed from orbit may contain boulders, craters, steep slopes, loose material, or shadows that make a landing dangerous. These hazards are especially important for missions targeting scientifically valuable but challenging locations, including areas near the lunar south pole.

A future lander using related capabilities could compare onboard observations with stored maps, calculate its position during descent, identify hazards in the landing area, and adjust its flight path toward a safer point. The final decision-making process would occur quickly and largely onboard the vehicle.

NASA has been developing SPLICE through several related technical areas, including terrain-relative navigation, hazard detection, and precision descent guidance.

## Why Planetary Landings Need More Autonomy

Landing systems have improved significantly since the Apollo era, but every planetary landing remains a complex engineering challenge.

Traditional landing approaches often rely heavily on preselected landing ellipses: broad areas where a spacecraft is expected to arrive after accounting for navigation uncertainty. A larger landing ellipse can increase mission flexibility, but it may also keep spacecraft farther away from specific scientific targets or safer terrain.

For future exploration, mission planners want to land closer to features such as permanently shadowed craters, ancient geological deposits, ice-rich regions, or locations suitable for surface infrastructure. These places may be scientifically compelling, but they can also be rough, uneven, and difficult to reach.

Autonomous navigation could reduce uncertainty during descent. Instead of treating the surface as a largely fixed target chosen well before launch, a spacecraft could evaluate conditions as it approaches and refine its landing path.

This capability is particularly valuable where communication delays prevent real-time piloting from Earth. Even at the Moon, signals take roughly 1.3 seconds to travel one way. During a fast descent, that delay is long enough that ground controllers cannot manually react to every new terrain observation.

At Mars and more distant destinations, the challenge is even greater. Communications delays can range from several minutes to much longer, making autonomous guidance essential for the final landing sequence.

## What the Drone Test Demonstrated — and What It Did Not

The reported flight used an Alta-X drone, a heavy-lift multirotor aircraft, to carry the SPLICE payload through simulated landing maneuvers. A drone test allows engineers to expose hardware and software to real motion, vibrations, changing viewpoints, and time-sensitive navigation decisions without launching a spacecraft.

This kind of testing can help NASA evaluate whether sensors, processors, algorithms, and control systems work together as intended. It also provides a way to identify issues before the technology is integrated into an expensive planetary mission.

However, the test does not fully reproduce a lunar landing.

The Moon has no atmosphere, different gravity, extreme temperature conditions, abrasive dust, unusual lighting, and no terrestrial navigation infrastructure. A drone also uses rotors and aerodynamic flight, while lunar landers rely on rocket engines. Those differences mean that successful drone flights are an important development step, not a final proof that the system is ready for a lunar mission.

NASA’s announcement indicates that the experiment demonstrated promise, but the provided source summary does not specify every performance metric, such as landing accuracy, hazard-detection distance, software processing time, or the exact degree of autonomy used during the flight. Those details would be needed to compare the result directly with requirements for a specific lunar lander.

## Terrain-Relative Navigation and Hazard Avoidance

Two related concepts are central to advanced landing systems.

### Terrain-Relative Navigation

Terrain-relative navigation helps a vehicle determine where it is by comparing images or sensor data gathered during descent with a preloaded map of the target region.

This method can supplement inertial navigation systems, which track motion using accelerometers and gyroscopes. Inertial systems are highly useful, but small errors can accumulate over time. By recognizing known terrain features, a spacecraft can improve its estimate of its own position.

NASA demonstrated terrain-relative navigation during the Mars 2020 mission. The Perseverance rover used a system called Terrain-Relative Navigation during its February 2021 landing to help steer away from hazardous terrain in Jezero Crater.

### Hazard Detection and Avoidance

Hazard detection focuses more directly on the local touchdown zone. Sensors and onboard software assess the terrain below, looking for hazards such as large rocks, slopes, craters, and other features that could threaten a lander.

A guidance system can then select a safer nearby location within the vehicle’s reachable area. This process must be fast because a spacecraft has limited fuel and only a short period to redirect during descent.

SPLICE is significant because it brings related functions together as an integrated landing capability rather than treating navigation, terrain assessment, and guidance as isolated components.

## Why This Matters for Artemis and Robotic Missions

NASA’s Artemis program aims to return astronauts to the Moon and establish a more sustained lunar exploration presence. While SPLICE itself is a technology development effort rather than a crewed lunar landing mission, the underlying problem it addresses is central to Artemis-era operations.

Future lunar missions may need to land cargo, scientific instruments, robotic vehicles, and eventually crews in places that are less forgiving than the broad, relatively smooth sites chosen for many earlier landings.

Precision landing could also support repeat access to the same region. That may be useful for building surface operations over time, delivering supplies near prior hardware, or placing instruments in specific geological settings.

For robotic science missions, better landing autonomy could open destinations that were previously considered too risky. On Mars, icy moons, asteroids, and other bodies, safe landing or close-proximity operations depend on a spacecraft’s ability to understand its surroundings without waiting for instructions from Earth.

## A Step Toward More Capable Landers

NASA’s SPLICE drone experiment should be viewed as a technology maturation milestone. It suggests that the agency is continuing to test practical ways to give landers more awareness and decision-making ability during one of the riskiest phases of a mission.

The reported result is encouraging, but it is not the same as a full planetary-flight demonstration. Additional testing will be needed to validate performance under more representative conditions and to qualify any future system for use on an actual spacecraft.

Still, the direction is clear. As exploration moves toward more demanding landing sites, spacecraft will need to do more than follow a preprogrammed trajectory. They will need to identify where they are, understand what lies below them, and make rapid decisions about where it is safe to land.

Authority sources (external links):
– [NASA’s SPLICE navigation experiment announcement](https://www.nasa.gov/centers-and-facilities/armstrong/nasa-navigation-experiment-shows-promise-for-planetary-landings/)
– [NASA overview of precision landing and hazard avoidance technologies](https://www.nasa.gov/directorates/stmd/space-tech-research-grants/early-stage-innovations/precision-landing/)
– [NASA Mars 2020 Terrain-Relative Navigation information](https://mars.nasa.gov/mars2020/spacecraft/rover/terrain-relative-navigation/)
– [NASA Artemis program mission overview](https://www.nasa.gov/artemis/)
– [European Space Agency information on lunar exploration](https://www.esa.int