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Space is getting crowded. With over 10,000 active satellites and millions of pieces of debris floating around up above Earth’s atmosphere, we need better ways to see what's happening beyond Earth's atmosphere. That's where Non-Earth Imaging (NEI) comes in.
If you've heard the term before, you might be wondering what it actually means and why it matters. Let’s explore everything you need to know about NEI, from its fundamental principles to how HEO uses non-Earth imaging and real-world applications that are making space more transparent and sustainable.
Non-Earth Imaging (NEI) itself is straightforward: it's using satellites in space to take pictures of other objects in space. While most satellites (like Earth observation satellites) point their cameras down at Earth, NEI systems rotate in other directions to photograph nearby satellites, debris, and spacecraft.
This space-to-space imaging capability provides visual awareness of what’s happening in orbit. Operators can inspect satellites, monitor health and status of space objects, characterise space debris, and understand the behavior of space assets in ways that ground-based radar and telescopes can’t match.
This covers several scenarios:
Getting the ideal image in space isn’t easy. Orbital mechanics make NEI far more complex than it looks. Unlike taking photos on Earth where you can move your camera wherever you want, satellites follow specific orbital paths. For one satellite to photograph another, several conditions need to line up:
Relative Positioning: The photographing satellite needs to be close enough, typically 30-300 kilometres away, to get useful images. This distance balances image quality with the practical constraints of space operations.
Orbital Timing: Both satellites need to be in the right place at the right time to create a “window” of opportunity. This depends on their altitudes, orbital paths, and how fast they're moving.
Lighting Conditions: You usually need sunlight to illuminate the target, though some advanced sensors can work in different lighting.
Different imaging distances serve different objectives. From farther away, NEI provides broader context, ideal for identifying unknown objects, monitoring constellations, or characterising satellite behaviour. As the imaging satellite gets closer, the images become more detailed. This enables inspection-level analysis of components such as antennas, solar arrays and damage. It is critical for diagnosing issues or validating configurations.
NEI missions generally fall into two categories:
Fly-by Inspections: Satellites collect imagery during natural orbital passes. This is non-invasive, requires no fuel-intensive manoeuvres, and can be repeated frequently. Fly-bys are cost-effective, lower-risk, and highly scalable. While this is ideal for persistent monitoring across many targets, you only get photos when orbital mechanics naturally align the satellites.
Close-in Inspections: A satellite actively maneuvers to approach the target using Rendezvous and Proximity Operations (RPO). While this provides more control over imaging conditions and can capture more detailed images, it requires specialised spacecraft capabilities, significant propellant, and careful mission planning to avoid creating collision risks.
At HEO, we've pioneered a unique approach to Non-Earth Imaging that maximises coverage and efficiency while minimizing costs and risks. Our method centres on fly-by inspections that leverage the natural motion of spacecraft to create imaging opportunities without the complexity and expense of dedicated proximity operations.
Our proprietary software platform, HEO Inspect, handles the entire operation autonomously. It captures raw sensor data and turns it into useful information that meets individual customer needs.
HEO Inspect doesn't just control our own sensors either. It's designed to wrap and control various space-based hardware platforms, including:
Instead of deploying our own constellation, we integrate with existing satellite operators to expand our reach. Partners like Axelspace, Satellogic, and BlackSky provide access to their sensors during available windows, while Sidus Space and Impulse Space host our proprietary cameras on their platforms. This collaborative model extends our coverage without contributing to orbital congestion.
By orchestrating a distributed network of sensors, we’re able to image hundreds of different satellites repeatedly and from varying angles, delivering a level of frequency and perspective that single-platform systems can’t achieve across multiple constellations. This high revisit rate enables persistent monitoring, rapid anomaly detection, and near real-time situational awareness. Combined with HEO Inspect’s analytics, customers receive actionable insights in the context of their mission.
Today, most solutions focus on where an object is in orbit. Very few address what an object’s condition is at any given time. If a satellite fails, or if space debris approaches, operators often have no way to see the problem directly.
We believe the solution lies in imaging objects from other satellites. By capturing pictures from orbit, you can assess the state of a satellite, detect anomalies, and make informed decisions about mitigation or repair. Seeing the object is the only way to truly understand it.
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Defence and intelligence agencies use NEI to understand what adversary satellites can and are doing. High-resolution images reveal antenna configurations, solar panel setups, and other details that ground-based radar can't provide. By regularly imaging the same satellites, they can establish normal behaviour patterns and quickly spot changes that might indicate new capabilities or missions. Visual confirmation of satellite activities also helps analysts understand potential threats, verify intelligence reports, and make informed decisions about space security postures.
Operators use NEI to support their satellite missions from cradle to grave. Once a satellite is deployed into space, NEI can identify the satellite and verify its health, especially when telemetry is unclear. Visual checks confirm whether antennas have deployed, solar panels are properly deployed and sun-facing, or physical anomalies are present. As constellations grow, NEI enables scalable, autonomous inspection of entire fleets.
Organisations use NEI to study space debris in detail, understanding how it fragments and behaves over time. This information helps develop better strategies for dealing with orbital debris, including assisting in active debris removal and in-orbit servicing & manufacturing.
Satellite Operators get certainty about their spacecraft health, faster responses when problems occur, and better mission planning through improved situational awareness.
Defence Organisations gain tactical and strategic intelligence capabilities beyond what radar provides, real-time threat assessment, and comprehensive awareness of adversary satellite capabilities and behaviour.
Regulatory Bodies can make better decisions about space traffic management, improve debris tracking, and enforce sustainability guidelines with actual visual evidence.
Non-Earth imaging and satellite inspection have traditionally been the domain of major governments with sophisticated orbital hardware. However, as thousands of new satellites launch, the inspection challenge has shifted from capability to scale. What once required just a handful of skilled analysts and specialised satellites now demands automated solutions to keep pace with an exponentially growing orbital population.
At HEO, we transform this process through end-to-end automation, from identifying optimal imaging opportunities to tasking satellites and extracting mission-critical insights. These insights enable us to develop derivative products tailored to specific customer needs, ultimately contributing to a more transparent and sustainable space environment for all operators.
Non-Earth Imaging provides a way to observe and operate in space. As orbital environments become more complex and crowded, the ability to see what's happening in real-time becomes essential.
Through approaches like automated fly-by inspections and partnerships with existing satellite operators, NEI is a practical tool for space operations. Whether supporting national security, ensuring satellite performance, or advancing sustainability efforts, NEI provides the visual information needed to navigate our increasingly busy space environment.
We believe the future of space operations depends on transparency, sustainability, and cooperation. Non-Earth Imaging is a key technology making this possible.
