Confined Space Inspection Drones: Remove People From Danger, Capture Better Data

Why confined space inspection drones change the economics of inspection

Traditional internal inspection of a tank or vessel means building scaffolding, issuing confined space entry permits, posting hole watch, monitoring atmosphere continuously, and putting a person inside a structure that may contain residual product, oxygen-deficient air, or fall hazards. A drone built for these environments removes the inspector from the danger entirely. The operator stays outside the manway while the aircraft flies the interior, streams live video to a tablet, and records data that is location-tagged for reporting.

The downstream value compounds quickly. Eliminating or reducing scaffolding cuts both direct cost and the days of downtime needed to erect and strike it. A full digital twin or point cloud of the asset interior gives engineers a permanent, measurable record they can revisit between turnarounds instead of relying on a handful of photos. For an in-depth look at the financial case, see our guide on reducing scaffolding costs and downtime with drone inspections.

Because these assets are enclosed steel structures, GPS does not work inside them. Every platform below solves navigation a different way, and every one is designed to tolerate contact with walls, beams, and internal structure rather than relying on open airspace.

Three platform types for GPS-denied and confined spaces

Measur groups its indoor and confined space aircraft into three design families. Each makes a deliberate trade between protection, endurance, survey-grade data, and the size of the opening it can pass through. You can browse the full range in the confined space drones collection.

1. Caged drones: maximum collision tolerance indoors

A caged drone wraps the entire aircraft in a protective shell so it can bump beams, walls, and internal structure and keep flying. The Flybotix ASIO X is built around a full protective cage and a patented coaxial bi-rotor propulsion system that delivers extended endurance with built-in redundancy. If a rotor is disturbed, the coaxial design helps the aircraft land safely rather than dropping.

For inspection payload, the ASIO X carries a true 4K (3840x2160) RGB camera that captures 12-megapixel stills in flight, a FLIR infrared thermal camera (160x120px at 9fps) for spotting defects invisible in normal light, and up to 40,000 lumens of oblique lighting to turn pitch-black interiors into daylight. More than twelve onboard sensors update altitude and position thousands of times per second, and an obstacle-repulsion field continuously analyzes the surroundings to slow and stop the aircraft before contact. A LiDAR payload and a gas detector for hazards such as H2S, CO, and O2 are available. Learn how the platform handles tight interiors in our guide on navigating complex indoor environments with the Flybotix ASIO X.

2. Tethered survey-grade systems: unlimited endurance, rich 3D data

When the priority is dwell time and survey-grade output rather than the smallest possible opening, a tethered system wins. The ScoutDI Scout 137 flies on a custom tether (60 metres extended) that delivers power, control, and a fully wired data link from the ground station. Because power comes up the tether, flight time is effectively unlimited, so operators can take their time, pause mid-air to discuss findings, and capture every point of interest in one session.

The Scout 137 navigates and positions itself using an onboard 3D LiDAR system (an Ouster OS0-128, 128-beam unit with a 35 to 100 m range and 90-degree vertical field of view) combined with built-in SLAM, so it builds a live map of the interior with no GPS required. Its gimbal-stabilized 4K camera offers 3.5x optical zoom and autofocus for detailed visual data. Every inspection finding is location-tagged and rendered in a 3D point cloud inside the Scout Portal software, where teams can move chronologically through a flight or jump to a specific location on the asset. A Tether Launch and Recovery System (TLRS) enables through-hatch deployment, an integrated gas sensor monitors air quality during flight, and a UTM ultrasonic payload combines surface preparation and thickness measurement in a single pass. See our deep dive on continuous industrial inspection with the ScoutDI Scout 137.

3. Ducted drones: fly close to people and equipment

A ducted design encloses the propellers inside the airframe so there are no exposed blades at all. The Cleo Dronut X1 is the world's first bi-rotor ducted drone, built on a ruggedized composite frame that lets it operate comfortably near people, around sensitive equipment, and in the tightest GPS-denied spaces. At roughly 420 g and about 6 inches across, it slips through openings that larger aircraft cannot.

The Dronut X1 is powered by a Qualcomm Snapdragon processor and an array of sensors including a 3D LiDAR module and five LiDAR rangefinders, so it can live-stream HD video and export a full point cloud of the interior. It carries a 4K (3840x2160) main camera with a 140-degree field of view, dual HD secondary cameras at 220 degrees, and four LED lights, with around 17 minutes of flight time per charge and AES-256 encrypted communications. The fully ducted, no-exposed-propeller design makes it inherently collision tolerant.

How the three platforms compare

Choosing the right platform for your asset

Start with the opening size and the data you need. If the asset has a small manway and you need to fly close to fragile internals or alongside workers, the ducted Dronut X1 is the most forgiving. If you expect a lot of contact with internal structure and want thermal plus high-lumen lighting in one aircraft, the caged ASIO X is purpose-built for it. If you need long, unhurried dwell time and a survey-grade 3D point cloud you can measure and revisit, the tethered Scout 137 is the strongest fit.

Data strategy also matters. Where you need accurate 3D geometry of a GPS-denied interior, LiDAR-equipped platforms typically outperform image-only capture; our guide on LiDAR vs. photogrammetry in GPS-denied environments walks through the trade-offs. And because confined space work carries strict regulatory and safety obligations, review ensuring safety compliance during indoor drone operations before you build your program. To see how these platforms come together on a real site, read our case study on digitizing a Canadian mining operation with confined space drones.

Not sure which system fits your tanks, vessels, or underground assets? Our team can match a platform and payload to your inspection scope. Request a quote and we will help you specify the right confined space solution.