Orbiting robots could help repair and power satellites in space

There are many such challenges. Because existing satellites were never intended to be serviced, they lack the markings, called landmarks, that would make it easier for a robot to visually orient itself with the moving satellite. There are no fasteners designed for the robot to hold on to. And the parts of a satellite that protrude, like antennas and solar panels, tend to be too fragile to grab.

Another problem is the time lag between the robot and the Earth. For a robot operating in geosynchronous orbit, at around 35,000 kilometers, distance and signal processing create a communication delay of several seconds between the robot and its controllers on Earth. The robot will therefore have to manage the most crucial tasks on its own.

On the plus side, the work can build on existing robotic arms in space, including two currently in use on the International Space Station.

For a demonstration mission, Henshaw and his fellow engineers plan to choose one of thousands of old, inactive satellites “parked” in distant orbits. A robot would match orbits with the satellite and maneuver about two meters away, using cameras and a laser rangefinder. When close enough, the robot uses one of its two arms to grab an aluminum ring that previously anchored the satellite to the launcher.

The other robotic arm would be able to nudge and prod solar cells or antennae that failed to deploy properly — a problem that happens every two or three years, Henshaw says. And it would be able to attach new instruments outside the satellites, such as more powerful transmitters, cameras or antennas.

Plans call for a space robot called SPIDER (pictured) to demonstrate the feasibility of on-orbit assembly. Her first task will be to assemble a seven-piece, three-meter antenna from parts she transports from Earth.


Sometime after 2025, NASA plans to launch an even more ambitious robot. The On-orbit Servicing, Assembly, and Manufacturing 1 (OSAM-1) robot would initially handle a complex refueling operation of an existing satellite. Then he would demonstrate that he can build completely new structures in space.

Landsat 7 will be first on OSAM-1’s to-do list. Launched in 1999 by the US Geological Survey in low Earth orbit, at an altitude of around 700 kilometers, the work of the satellite has been taken over by more advanced satellites. But it offers scientists the opportunity to test robotic refueling.

“Twenty years ago, technicians powered the satellite in preparation for launch, and they never thought anyone would touch that interface again,” says Brent Robertson, NASA’s OSAM-1 project manager. .

OSAM-1 will use its robotic arm to cut through a layer of insulation, cut two wires and unscrew a bolt before connecting a hose and pumping out 115 kilograms of hydrazine fuel, Robertson says. (See the video here.)

Although repair and maintenance of existing satellites is the most immediate objective, in-orbit assembly and manufacturing is potentially more important in the long term.

OSAM-1, for example, has an additional mission that will carry a separate robot called Space Infrastructure Dexterous Robot (SPIDER), designed to demonstrate that it can put things together in space. SPIDER’s first task will be to assemble a seven-piece three-meter antenna that it has carried into orbit.

Using a process similar to 3D printing, OSAM-1 will also aim to show that it can build structural components from scratch, creating strong yet lightweight composite beams from carbon fiber spools and other textiles. Beams like these could be connected to form structural components of a satellite or other structures in orbit.

If the missions being planned are successful, robotics could usher in a new era of space construction that is unaffordable today – fuel depots, space mining operations, larger space stations for space tourism, and even spacecraft bound for Mars built in orbit.

“We want to demonstrate that we can build these things. No one has done this before,” Robertson says. “If you have the ability to assemble things in space, you can bring your own hardware or have hardware sent to you. And you can build much bigger things.

This article originally appeared in
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