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The robotic Sputnik 1 launched back in October of 1957, making history as earth’s first artificial satellite. Two decades later, the Voyager missions began a process that has seen robots being sent to the outer reaches of our solar system… and beyond. More recently, a machine named CIMON (Crew Interactive Mobile Companion) became the first AI-enabled robot in space. Indeed, robots come in many forms and have many uses - but in this piece, we’re going to discuss a lower profile use of space robotics - ‘orbital manipulation‘.

What is orbital manipulation? What can we do with it?

Orbital manipulation (or ‘in-orbit manipulation’) refers to the use of robotic means to carry out tasks in orbit. Although sophisticated, it’s not particularly new.

The now famous ‘robotic arm’ of the space shuttle, the Canadarm (also known as the Shuttle Remote Manipulator System or ‘SRMS’) - was first tested in orbit back in 1981. It has been used, amongst other things, to build the International Space Station (ISS) and to release the Hubble Space Telescope. Though Canadarm1 was retired in July 2011, Canadarm2 lives on today in the ISS.

And, as orbital manipulation increases in capability, it will find new uses in space. Here are four examples.

Clearing ‘space junk’

One of the major (and growing) challenges is ‘space junk (also known as ‘space pollution’ and ‘space debris’). Space junk describes a range of debris left by humans in orbit, hurtling around the earth at roughly 18,000 mph. On the small scale, this includes paint flecks that have broken off of craft, and, on the larger scale, failed satellites and discarded rocket boosters.

This space junk increasingly falls into conversations on the impact we have on the environment - with space being part of that environment. As the amount of this junk grows, and as our need to use the space environment increases, it will become an increasing problem.

As such, technologies that are able to catch rapidly moving debris in order to safely deorbit it will be essential for the safety of near-earth operations. Ideas that have been envisioned include net-like devices and electro-adhesive boom arms.

Moving craft

NASA describes the process of seizing a craft or module via robotic means as a ‘cosmic catch’. Moving craft has already proved to be important, and will be even more so, as we continue to make greater use of space.

A major consideration is moving things that lack their own propulsion systems - particularly those that are delicate, or that carry sensitive-payloads. It’s far easier to dock with a craft that has its own means of movement (ie. its own engine).

This will be particularly important with satellites. Traditionally, the approach to satellite coverage was to build a small number of larger, more expensive satellites. But this is changing. Newer satellite ‘constellations’ consist of more numerous, smaller, and more cheaply built ‘microsatellites’. One such high-profile example is SpaceX, which plans to launch roughly 12,000 satellites as part of its Starlink constellation.

The result of such constellations is a greater volume of craft, that have a greater probability of failing. Having a way to safely manage them will be essential.

Changing payloads and undertaking repairs

For decades, space missions have helped to bring payloads up into orbit. For example, in 2018, astronauts replaced Canadarm2’s ageing ‘hands’. And, as the number and variety of platforms in space increases, interchangeable payloads could offer cost savings and provide greater task flexibility on existing platforms. For example, it’s cheaper to repurpose an existing unused platform, than to deorbit it and launch another in its place. But this is still some way off yet.

In-orbit manufacturing

Made in Space’s Additive Manufacturing Facility (AMF), which lives on ISS, provides the first example of in-orbit manufacturing. Made In Space claim to have manufactured over 200 tools, assets and parts to date. This, however, is just the first step in a long road.

It will be quite some time before we see large-scale orbital manufacturing. Currently, the majority of objects are manufactured on the surface, and then launched into orbit. In some cases, various components travel up on different payloads, before being assembled in space (by a robot).

The problem, of course, is that getting material into space is expensive; with the price is proportionate to the size and mass of the payload in question. And, for delicate components, the sheer force of launch is another consideration.

In future, the hope is for the robotic construction whilst in orbit. This could include individual components, all the way up to entire platforms, like crewed stations or satellites.

It’s a realistic prospect. Back on earth, industrial robots (with some supervision) are already being used to build everything from cars to sophisticated electronic components. The ISS was built, in large part, in space. As such, we can expect to see further space applications as AI and automation develops.

Not only would this save significantly on costs, but it would also help to meet environmental targets - for example, the UK’s target for Net Zero greenhouse gas emissions by 2050.

A long history and a bright future

As robotic uses go, it doesn’t grab headlines like Voyager or Sputnik, but orbital manipulation will be an integral part in our transition to a space-faring species.

In the shorter term, we can expect to see developments in docking and berthing. ‘Docking’ refers to the joining of two free-flying space vehicles. ’Berthing’ refers to operations in which robotic means (usually an arm) is used to connect a vehicle or module that lacks thrust with another craft.

QinetiQ is currently developing the International Berthing and Docking Mechanism (IBDM) for just this purpose. Previously, docking mechanisms have struggled with the issue of inertia, particularly with craft or modules that are unable to decelerate under their own power as they move in to dock.

IBDM overcomes this by absorbing relative movement - which minimises the impact forces and resultantstructural loads between two objects while docking orberthing. Not only is this safer, it’s also more efficient,increasingly the likelihood of successful docking.

IBDM is also extremely adaptable, allowing it to work with a range of object sizes and configurations. This facilitates a range of tasks: everything from resupply, to using a station for a starting point for a long-range mission.