In-space servicing and assembly

Also known as Orbital shipyards, On-orbit assembly, On-orbit servicing

In-space servicing and assembly means building, repairing or upgrading spacecraft in orbit rather than on the ground. Assembly from launched modules is established through the International Space Station, while robotic servicing is only beginning to fly and robotic construction from raw material remains at test or proposal stage.

Research and prototypesDemonstratedReviewed 21 Oct 2026
AI illustration · Illustrative scene, not a photograph of the specific device or experiment.

In plain language

Some work in orbit is already routine. Astronauts and robotic arms assembled the International Space Station from parts that were built on Earth and launched separately. Robotic servicing is newer: a servicing vehicle can approach a satellite and carry out a physical task, such as installing a propulsion module, although no completed repair has yet been reported from the 2026 launch.

The practical question is which task saves enough launch mass, time or replacement cost to justify the extra vehicles and operations. Life extension and module replacement are the nearest to everyday use. Building large structures from raw material in orbit is still a proposal, and no operational orbital factory has been shown.

Technical explanation

The term covers four different capabilities: assembly from delivered modules, servicing and upgrades of existing spacecraft, manufacture from launched feedstock, and manufacture from local space resources. Only the first is well established. NASA's history of station construction records that assembly required 37 Space Shuttle flights, two launches each of the Russian Proton and Soyuz rockets, and three commercial SpaceX Falcon 9 vehicles, and that Canadarm2 added a robotic capability described as essential for future assembly and maintenance tasks. The station's elements were manufactured and tested on Earth, so the ISS shows that complex integration can happen in orbit. It does not show that raw stock can be turned into a large pressure vessel or truss there.

Servicing is flying in early forms. NASA reports that Northrop Grumman's Mission Robotic Vehicle, hosting the NASA-supported Robotic Servicing of Geosynchronous Satellites (RSGS) payload, lifted off from Cape Canaveral on 21 July 2026 and was en route to geosynchronous orbit. NASA describes its intended role as inspecting satellites and installing propulsion modules to extend their lives. No completed repair was reported at the time of the NASA article. An earlier NASA project, On-orbit Servicing, Assembly, and Manufacturing 1 (OSAM-1), was discontinued in March 2024 because of continued technical, cost and schedule challenges.

Robotic assembly is mostly at test scale. A 2023 paper published through NASA's Technical Reports Server reports autonomous joining of 1:2.8 scale TriTruss modules by a UR10e manipulator on a test stand, using trajectory generation from a worksite model. The test verified the concept of operations and grapple-tool software. It did not report full-scale performance or operation in the space environment.

What the evidence says

Each statement is typed by the strength of its evidence and linked to the source that supports it.

Demonstrated Shown in a published experiment, test or shipping product.

NASA's history of station construction records that assembly required 37 Space Shuttle flights, two launches each of the Russian Proton and Soyuz rockets, and three commercial SpaceX Falcon 9 vehicles.

Sources: [1] · Assembly history

NASA describes Canadarm2 as essential for future assembly and maintenance tasks, and says assembly and maintenance would not have been possible without hundreds of hours of spacewalks.

Sources: [1] · Assembly history

NASA discontinued the OSAM-1 project in March 2024 due to continued technical, cost and schedule challenges. The article also points to a broader community shift away from refuelling unprepared spacecraft.

Sources: [3] · Project update

NASA reports that the Mission Robotic Vehicle, carrying the Robotic Servicing of Geosynchronous Satellites payload, launched on 21 July 2026 and was en route to geosynchronous orbit. No completed repair on a client satellite is reported in the article.

Sources: [4] · Launch report

A 2023 test used a 1:2.8 dimensionally scaled TriTruss structure on a test stand, with a UR10e manipulator and an autonomous trajectory planner, to pick up and join truss modules.

Sources: [2] · Abstract and test description · medium confidence

The 2023 TriTruss paper reports verification of the assembly concept of operations and grapple-tool software. It does not report full-scale performance or operation in the space environment.

Sources: [2] · Verification scope

Reported, unverified Stated by a company or team but not independently confirmed.

ESA reports that Project Cassandra's composite tests used samples and a prototype, with no test site given beyond a laboratory photo caption, and with embedded fibre-optic sensors locating damage and local heating triggering repair. ESA does not mention an in-orbit demonstration.

Sources: [5] · Project description · medium confidence

CompPair reports that its HealTech CS03 composite repairs microcracks in minutes when moderate heat is applied. The announcement does not state the temperature, test method or test duration.

Sources: [6] · HealTech CS03 description · medium confidence

Proposed A design or plan that has not yet been built or tested.

The Mission Robotic Vehicle is intended to inspect satellites in orbit and extend their lives by installing propulsion modules. This is a stated plan, not a record of completed service.

Sources: [4] · Launch report · medium confidence

Limitations and open problems

  • The ISS shows assembly from Earth-built elements. It does not show that raw feedstock can be turned into large structures in orbit.
  • The 2023 TriTruss assembly test used a 1:2.8 scale structure on a test stand and did not report full-scale performance or operation in the space environment.
  • A launch is not the same as a completed service. The 2026 servicing vehicle had not been reported as completing work on a client satellite at the time of the NASA article.
  • NASA's OSAM-1 page describes a broader shift away from refuelling unprepared spacecraft, so retrofitting satellites that were not designed for service remains a hard problem.
  • The sources reviewed here do not give verified cost figures for orbital servicing, assembly or manufacturing, so the economics of a yard remain unproven.

Possible future uses

Speculative

Ideas, not predictions. None of these has been demonstrated.

  • Assembling telescope apertures or antennas too large for a launch fairing from segments launched separately and joined in orbit.
  • A robotic service depot that extends the life of satellites designed with standard grapple points and service ports.
  • Building structures in orbit from materials recovered or mined in space, once an orbital supply chain exists.

Product concepts: Cooperative-target servicing tug, Orbital satellite assembly robot

Timeline

  1. Oct 2023A paper on autonomous assembly of scaled TriTruss modules is published through NASA's Technical Reports Server, describing a test on a ground test stand. Sources: [2]
  2. 1 Mar 2024NASA announces the discontinuation of the OSAM-1 refuelling and robotic assembly project, citing technical, cost and schedule challenges. Sources: [3]
  3. 3 Mar 2026ESA reports Project Cassandra test results on composite samples and a prototype, with embedded sensing and local heating. No in-orbit test is reported. Sources: [5]
  4. 21 Jul 2026The Mission Robotic Vehicle, carrying the RSGS payload, launches from Cape Canaveral towards geosynchronous orbit. Sources: [4]

Futures this could help bring about

AI illustration
How far away?

Clearing dead satellites and space junk from orbit

Engineering prototypes · 2 of 5 steps done

AI illustration
How far away?

Living in a spinning space habitat

Science demonstrated · 2 of 7 steps done

Related breakthroughs

Glossary

On-orbit servicing
Work done on a spacecraft in orbit, such as inspection, refuelling, life extension, relocation or module replacement.
Grapple fixture
A standard attachment point on a spacecraft that a robotic arm or servicing vehicle can grip.
Geosynchronous orbit
An orbit about 35,800 kilometres above the equator where a satellite keeps pace with Earth's rotation, used by many communications satellites.
Feedstock
The raw material, such as bar, wire, pellets or prebuilt blocks, that is processed into a finished part.

Sources

  1. government report
    ISS20th: High-Flying Construction
    NASA, 16 Dec 2019. Accessed 21 Oct 2026.
  2. conference paper
    Test Results for Autonomous Assembly of Modular Space Structures
    John R. Cooper, Jacob R. Martin, Olive R. Stohlman et al.. NASA Technical Reports Server (AIAA ASCEND 2023), Oct 2023. Accessed 21 Oct 2026.
  3. government report
    Update on Status of NASA's OSAM-1 Project
    NASA, 1 Mar 2024. Accessed 21 Oct 2026.
  4. government report
    Robotic Servicing Mission Launches with NASA Support
    NASA Goddard Space Flight Center, 21 Jul 2026. Accessed 21 Oct 2026.
  5. news
    Self-repairing spacecraft could change future missions
    European Space Agency, 3 Mar 2026. Accessed 21 Oct 2026.
  6. news
    CompPair wins ESA Innovation Award
    European Space Agency, 29 Sept 2026. Accessed 21 Oct 2026.

Revision history

3 changes since this profile was created.

Changes on 21 Oct 2026
Published on owner instruction (content loop iteration 6)2124aeb
Sources and claims re-checked against originalsfbb434c
Initial profile drafted from Codex research note and primary sources0eba374

What it took to get here

The inventions this technology was built on, oldest foundations at the top. Lines show what each one required.

Built on: In-space servicing and assembly Unlocked Being researched Locked
  1. 2017Asteroid miningResearch and prototypes Being researched.
  1. 2023In-space servicing and assemblyResearch and prototypesRequires: Asteroid mining. Being researched.