In-orbit servicing, assembly, and manufacturing (ISAM) is an emerging field within the aerospace industry that involves the use of robotic technology to perform various tasks in space, such as repairing and maintaining satellites, assembling new structures, and manufacturing materials. This technology has the potential to revolutionize the way we operate in space, making it more cost-effective and efficient.
One of the key challenges in the development of ISAM is the need for advanced robotics technology that can operate effectively in the harsh environment of space. This requires the development of new hardware and software systems that can withstand the extreme temperatures, radiation, and vacuum conditions of space. In recent years, significant progress has been made in this area, with several companies and research organizations working on the development of ISAM technology.
One example of this is the NASA Robotic Refueling Mission (RRM), which was designed to demonstrate the feasibility of using robots to refuel satellites in orbit. The RRM successfully completed its mission in 2016, showing that it is possible to use robotic technology to perform complex tasks in space. This technology has the potential to extend the lifespan of satellites, reducing the need for costly replacements and enabling more sustainable operations in space.
Another example is the development of autonomous manufacturing technology for space. This involves the use of robots to manufacture materials and components in space, potentially eliminating the need for costly and time-consuming launches from Earth. One company, Made In Space, has already demonstrated the ability to 3D print objects in space using a specialized 3D printer. This technology has the potential to enable the construction of new structures and habitats in space, paving the way for long-term human presence in space.
In conclusion, the field of in-orbit servicing, assembly, and manufacturing is rapidly evolving, with significant progress being made in the development of advanced robotics technology for use in space. This technology has the potential to revolutionize the way we operate in space, enabling more efficient and cost-effective operations. As the technology continues to develop, we can expect to see even more exciting developments in the future.
The following infographic provides a timeline of ISAM major advances and milestones from 1961 into the future.
🇺🇸 Gemini
Gemini demonstrated rendezvous, proximity operations, and docking (RPOD).
🇺🇸 NASA Space Tug Concept
The Space Tug concept was intended to be a reusable multipurpose space vehicle designed to transport payloads to different orbital inclinations. Utilizing mission-specific combinations of its three primary modules (crew, propulsion, and cargo) and a variety of supplementary kits, the Space Tug would have been capable of numerous space applications. The Space Tug program was cancelled.
🇺🇸 Skylab
Skylab demonstrated on-orbit repairs to fix critical components.
The Solar Maximum satellite was repaired in orbit by astronauts from the space shuttle mission STS-41C. The satellite design incorporated Orbital Replacement Units (ORUs) which streamlined the on-orbit repair process.

🇺🇸 STS-51A Recovery and Return Mission
One of the unique attributes of the Space Shuttle featured the ability to launch satellites into space and return them to Earth if needed. That capability was first demonstrated during the STS-51A mission in November 1984. Earlier in the year, the crew of STS-41B successfully deployed two communications satellites from Space Shuttle Challenger's cargo bay – Westar 6 for Western Union and Palapa B2 for Indonesia. The Payload Assist Module (PAM) upper stages of both satellites malfunctioned, leaving them in non-useable 160-by-600-mile high orbits instead of the intended 22,300-mile high geostationary orbits required for their normal operations. While both satellites remained healthy, their own thrusters could not boost them to the proper orbits. So NASA devised a plan to have astronauts retrieve the satellites during Extravehicular Activities (EVAs) or spacewalks using the jetpack known as the Manned Maneuvering Unit (MMU), after which the shuttle's Canadian-built Remote Manipulator System (RMS) or robot arm would grapple them and place them into the cargo bay for return to Earth. The mission was a success.
🇺🇸 Hubble Space Telescope
As of 2022, Hubble Space Telescope “Hubble” has been serviced five times, which included replacement of circuit boards, the addition of hardware to correct a mirror flaw, regular upgrades of the scientific instruments, and the installation of a device to facilitate deorbit at the end of mission lifetime. Also, as of 2022, NASA is exploring options to reboost Hubble to a higher orbital altitude.
🇯🇵 Engineering Test Satellite VII
The Engineering Test Satellite VII (ETS-VII) successfully made the first remotely-controlled unmanned rendezvous docking between two spacecraft in history.
DART proved the technologies required for spacecraft to locate and rendezvous with another spacecraft without direct human guidance. While NASA has performed rendezvous and docking missions in the past, astronauts have always piloted the spacecraft. The autonomous rendezvous technologies demonstrated by DART represented a critical step for establishing an autonomous rendezvous capability for the United States and will lay the groundwork for future reusable crewed and uncrewed launch vehicle operations. Future applications of this technology include cargo delivery, space operations for the International Space Station (ISS) and other on-orbit activities such as satellite retrieval and servicing missions.
The Defense Advanced Research Projects Agency's Orbital Express demonstrated a full end-to-end robotic satellite servicing mission, the first of its kind. The mission included autonomous docking, fuel transfer, and ORU change-out essentially removing humans from the equation.
The Robotic Refueling Mission (RRM) investigation uses the International Space Station's two-armed robotic handyman, Dextre, to show how future robots could service and refuel satellites in space. RRM tests NASA-developed technologies, tools and procedures to refuel and repair satellites that were not originally designed to be serviced.
RRM2 is demonstrating technologies and capabilities related to satellite servicing including: testing a new inspection tool, practicing intermediary steps leading up to cryogen replenishment, testing electrical connections for “plug and play” space instruments, and working with decals that could help operations guided by machine vision go more smoothly. RRM2 is the continuation of the satellite-servicing demonstrations that began in the first phase of RRM operations.
RRM3 demonstrates the first transfer and long term storage of liquid methane, a cryogenic fluid, in microgravity. The ability to replenish and store cryogenic fluids, which can function as a fuel or coolant, can help enable long duration journeys to destinations like the Moon and Mars.
University-led mission launched in 2018 to test technologies for debris removal: net, harpoon, dragsail, and LiDAR vision. These demonstrations concluded in early 2019.
SpaceLogistics' Mission ExtensionVehicle-1 (MEV-1) became the first commercial servicer spacecraft to perform a docked life extension procedure upon an out-of-operation commercial satellite, Intelsat IS-901. This was followed by the MEV-2's docking to Intelsat IS-1002 on April 12,
Large family of Orbital Maneuvering Vehicles (OMVs) designed to serve as a modular platform for payload hosting and deployment. They are able to serve as space tugs to conduct orbit raising maneuvers for deployed payloads.
Defense Innovation Unit (DIU) has selected Sierra Nevada Corporation (SNC), NanoRacks, and Arkisys for Phase I contracts for the Orbital Outpost. It will be a self-contained, free-flying spacecraft capable of supporting assembly, microgravity experiments, logistics, manufacturing, training, and hosted payloads. Currently no schedule for orbital deployment.
An OTV designed for the last-mile delivery of CubeSats and microsats of mass up to 150 kg and to perform in-orbit experiments of hosted payloads. Four successful missions as of 2022, with over 70 payloads delivered to orbit.
Photon supports hosted payloads and last–mile satellite deployment ranging from LEO to deep space.
The Sherpa line of five OTVs are designed to provide final delivery to rideshare customers' desired orbits. Includes delivery to LEO, GEO, and Lunar orbits.
Astroscale's End-of-Life-Service by Astroscale-demonstration (ELSA-d) demonstrated key rendezvous and proximity operations technologies necessary for orbital servicing, and space debris removal.
Tanker-001 Tenzing was launched June 30, 2021 and is the world's first operational fuel depot. Tenzing stores High-Test Peroxide (HTP) propellant in a sun-synchronous orbit to refuel other spacecraft.
Vigorride is an OTV capable of transporting 200 to 750 kg of payload to LEO. Future plans include support for hosted payloads, refueling, repairing, inspecting, relocation, etc.
This National Strategy outlines how the United States will support and stimulate the United States Government (US), academic, and commercial ISAM capability development. It provides strategic goals to advance ISAM capability development discussed in the United States Space Priorities Framework. The next step following the strategy is to develop US implementation action plans to fulfill the goals.
Orbiter can transport up to 400 kg of payload to LEO. It can also support hosted payloads.
OrbitGuard, is a small satellite that can autonomously carry out far and near range rendezvous and provides SSA and inspection services to satellite operators. OrbitGuard 1 & 2 are slated to launch Q4 2022 onwards and provide services from 2023.
This small satellite provides one-on-one asset inspection capabilities for high-value satellites. It is forecast to be launched in 2023.
Laura will provide asset inspection and monitoring using high definition cameras and sensors.
Fred will provide payload transportation and orbital adjustment for satellites to GEO and LEO.
Astroscale's Active Debris Removal by Astroscale-Japan (ADRAS-J) has been contracted for the initial phase of JAXA's Commercial Removal of Debris Demonstration (CRD2) program. A public-private collaboration, Phase 1 of this program is expected to launch in 2023. Once Phase 1 displays non-cooperative RPO capabilities, Phase 2 plans to demonstrate the removal of a launch vehicle's second stage in fiscal year 2025.
Atomos is developing Quark Orbital Transfer Vehicle (OTV) to deliver satellites to their desired orbits utilizing high-power electric propulsion and advanced RPO techniques. Expected launch in 2023.
The Reliant OTV comes in a Standard and Pro model to transfer satellites to different orbital altitudes. Reliant Pro will also have modular satellite upgrade and debris collection abilities.
Orbit Solutions to Simplify Injection and Exploration (OSSIE) is a modular and scalable orbital transfer vehicle designed to provide precise orbital injection and inclination changes for CubeSats and small spacecraft. Can deliver to Earth orbits, the moon, and beyond.
The Space Van is capable of transporting up to 400 kg of payload to LEO and GEO.
Optimus is capable of payload transport to LEO, GEO, and deep space. Future support for active debris removal, life extension, and in-space manufacturing.
🇯🇵 Astroscale ELSA–M
ELSA–M will be the world's first mission to de-orbit multiple small satellites.
VIA plans to offer last-mile transportation, AOCS takeover, and hosted payloads.
OSAM-2 will demonstrate the feasibility of using additive manufacturing technology (3D printing) and advanced robotics to build two beams on a free-flying satellite. The first beam will unfurl a surrogate solar array, and the second beam will be used to characterize additively manufactured structures in LEO.
DROID is planned to support asset inspection, orbital adjustment, and debris mitigation functionalities in LEO.
DARPA has partnered with SpaceLogistics to develop and deploy a robotic servicer or MRV. The program is called Robotic Servicing of GEO Satellites (RSGS). Naval Research Laboratory (NRL) will integrate robotic payload elements including manipulator arms. Launch planned for 2024.
The Mission Robotic Vehicle (MRV) will be a commercial servicing spacecraft with advanced robotics technology. The primary purpose will be the installation of Mission Extension Pods (MEPs) to provide propulsion augmentation. The MRV is also designed to address inspection and repair, relocations, propulsion augmentation, and replacement of parts and systems. Planned launch in 2024. This is part of the DARPA RSGS program.
Arkisys is building one of the first Business Platforms in Space for new Technology Hosting, Satellite Integration, Assembly and Resupply. The Arkisys Port supports scaleable rapid prototyping, new payload and technology testing, assembly and integration of new free-flying space platforms and destinations for orbital transfer vehicles and on-orbit assembly and manufacturing.
The MEK aims to repurpose the upper stage of launch vehicles for use as platforms for robotic manufacturing, servicing, etc. These platforms are intended to be controllable and function across multiple orbits.
The ATRIS is an optional stage positioned on top of Ariane 6's upper stage, which will allow the rocket to place several satellites into different orbits in a single launch, or to inject a satellite directly into its final orbit, optimizing a wide scope of missions.
OSAM-1 (previously known as RESTORE-L) will use a robotic arm and tools to grapple Landsat 7 and provide the Earth-observing satellite launched in 1999 with more fuel. Following the servicing, the space vehicle's Space Infrastructure Dexterous Robot (SPIDER) payload will demonstrate in-space assembly by constructing a functional communications antenna from stowed parts, as well as in-space manufacturing by producing a spacecraft beam. SPIDER / OSAM-1 will robotically assemble seven individual components into one large antenna reflector.
Axiom Space's commercial space station is under construction. The first Axiom module is expected to dock with the International Space Station in 2024. Additional modules will launch each year. Axiom Station will become an independent commercial space station prior to the end of life of the ISS.
Other commercial space stations planned and proposed are described here Space Stations Current and Future.
Endurance performs autonomous rendezvous & docking and provides full AOCS capability for 5 years to an end of life GEO satellite. Life Extension Services will be available from 2025 onwards.
Orbital Fab plans to offer HTP propellant to GEO satellites starting in 2025. $20 million per 100 kg.
ESA selected ClearSpace for first ever debris removal of an ESA-owned item. ClearSpace-1 will use an experimental, four-armed robot to capture a Vega Secondary Payload Adapter (Vespa) left behind by ESA's Vega launcher in 2013. Expected launch in 2026.
European Robotic Orbital Support Services (EROSS) is a technology demonstration led by Thales Alenia Space intended to provide: life extension, refueling, inspection, controlled debris reentry, and other operations. On-orbit demonstration expected by 2026.
Upgraded version of OSSIE vehicle, planned to transport 1000 kg of payloads to lunar orbit.
The Life Extension In-orbit servicer is intended to provide life extension by acting as the propulsion system for client satellites. By using four robotic arms, LEXI can position itself to provide stationkeeping, attitude control, and other orbital relocation services. LEXI can dock/undock with clients, allowing it to service multiple clients per mission.
porkchop is planning to build a reusable orbital transfer vehicle.
Skyrora's Space Tug is planned to transport 350 kg into a 500 km SSO. Future scope may include the potential to: remove space debris, conduct inspections, and fix faulty satellites.
The Otter is a small space tug expected to support: satellite life extension, active debris removal, and autonomous transportation services.