In-Orbit Servicing (IOS): The Future of Satellite Maintenance and Space Sustainability

Akiko Hama, Client Executive, June 30, 2026
Innovation, Space and Satellites

For decades, the space industry followed a very expensive and wasteful pattern. When a satellite failed or ran out of fuel, that was the end of the mission. These massive machines, which often cost hundreds of millions of dollars to build and launch, would simply become high-tech trash.

Today, a new era is beginning as we move toward in-orbit servicing (IOS). This technology, also known as on-orbit satellite servicing, allows stakeholders to refuel, fix and even upgrade spacecraft while they are circling the Earth, as well as take out defunct spacecraft out of working orbits.

The value of being able to maintain assets in space is enormous. By using satellite life extension services, companies can keep their satellites working much longer than originally planned. This shift reduces the need to launch expensive replacements and helps keep space from becoming crowded with debris.

As more companies launch constellations of satellites into orbit, having a way to maintain them and/or to de-orbit them is becoming a vital part of a sustainable space economy.

What Is In-Orbit Servicing?

Think of in-orbit servicing as a mobile service expert or a roadside assistance service circling the Earth. It involves a “servicer” spacecraft traveling to a “client” satellite to perform specific tasks. This is very different from how we traditionally handled satellites, where they were essentially single-use objects. Once they were launched, the units were on their own and only valuable until they stopped working.

How In-Orbit Servicing Works

Working on something that is moving at thousands of miles per hour in the vacuum of space is an incredible challenge. The process usually proceeds in a few careful stages to ensure nothing goes wrong. First, the servicer must locate and track the target satellite to determine its exact position and motion. This is followed by a series of manoeuvres where the servicer gets closer and closer to the client satellite.

Once they are close enough, the servicer uses a robotic arm or a specialised docking system to grab the client. This part is tricky because many older satellites were never designed to be caught or refuelled. After they are firmly connected, the servicer performs the job, which might be pumping in new fuel, swapping out a part or just being docked to provide longer propulsion life. Finally, the servicer returns the satellite to its proper path or moves it to a new location if needed.

Types of In-Orbit Servicing Missions

There are several ways a servicer can help a satellite. Life-extension missions are currently among the most common. In these cases, a servicer docks with a satellite that has run out of fuel and uses its own engines to keep the satellite in the right spot. Refuelling missions are another major category. Instead of staying attached, the servicer transfers propellant directly into the client’s tank, allowing it to keep moving on its own.

Then, there are missions that address repair and assembly needs. This may include fixing a solar panel that didn’t open correctly or replacing a camera with a newer version. There are also relocation missions where a servicer moves a satellite to a different orbit to help it reach a new market. Finally, inspection missions allow operators to get a close-up look at their satellites to diagnose problems that cannot be seen from the ground.

Key Technologies Enabling the IOS Revolution

Modern servicing missions rely on a mix of state-of-the-art hardware and software which may include artificial intelligence (AI) enabled elements. These tools allow machines to work together autonomously in a very challenging environment.

• Autonomous Rendezvous and Docking (ARD) systems. These systems allow a servicer to find and connect with another satellite without a human pilot controlling every move.
• Robotic manipulators and grapplers. Specialised mechanical arms serve as the servicer’s hands to grasp satellites that often have no easy handles.
• Standardized docking interfaces. Hardware similar to a computer USB-style port enables servicers to connect to satellites more easily.
• Vision-based docking sensors. Optical, laser and lidar sensors and ultrasonic systems are changing how satellites dock in space. They help the servicer see the target and orient itself with millimetre precision during the final approach.
• Propellant transfer systems. Moving liquids in microgravity requires specialised pumps and seals to prevent leakage and ensure the fuel goes where it is intended.

Major In-Orbit Servicing Companies and Missions

A few prominent names are leading the way in this new field, including Northrop Grumman with its Mission Extension Vehicle (MEV-1). Orbit Fab is another pioneer, whose RAFTI Refuelling Port has been accepted as a standard by the U.S. Space Force.

Astroscale is a leader in applying space debris mitigation technologies to remove old, non-functional satellites. They work closely with agencies like the European Space Agency (ESA), which is also backing the ClearSpace-1 mission to remove space junk. While not every project succeeds—NASA recently had to cancel its expensive OSAM-1 mission due to rising expenses and technical hurdles—the knowledge acquired from these efforts is helping the entire industry grow.

In-Orbit Servicing Market Growth

The market for satellite servicing is already worth billions of dollars and is growing fast. This growth is being pushed by the rise of “mega-constellations” like Starlink, which have thousands of satellites that will eventually need to be maintained or safely removed from orbit.

For commercial operators, this makes sense. If you can spend a fraction of the cost of a new launch to keep an existing satellite working, your profits go up.

Strategic Importance of IOS

In addition to its vital role in space sustainability, cost efficiency and satellite lifecycle optimization, IOS will be essential in other ways. Governments see it as a matter of national security. Being able to inspect and repair defense satellites in orbit will provide an essential tactical advantage. Furthermore, every satellite that is refuelled or moved out of a crowded orbit reduces the risk of a collision that could create a dangerous cloud of debris.

Challenges and the Regulatory Setting

Though the potential is great, there are still many risks. A mistake during a docking attempt could cause a crash, making the debris problem even worse. There is also the issue of “dual-use” technology. A robot that can fix a satellite could also be used as a weapon to damage one. This creates tension between countries and makes the legal aspect very complicated.

Understandably, the laws governing space are still evolving to address this technology. The Outer Space Treaty is helpful, setting out some basic rules, but it doesn’t clearly specify who is responsible if a servicing mission goes wrong. There are also crucial questions about who owns a satellite during servicing.

As the industry matures, we will need clearer international rules to regulate space traffic and liability.

The Future of Space Logistics

Looking forward, we can imagine a time when space looks more like a busy industrial zone on Earth. We might see permanent orbital service stations where fleets of robotic tugboats are ready to assist any satellite in need.

This will eventually lead to a “space-as-a-service” model where companies do not just buy a satellite, but they pay for a guaranteed amount of time in orbit. These advances will also be essential for our ensuing missions to the Moon and Mars, where we will need to assemble and fuel large space structures in space.