This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Private companies are getting better at launching more mass into space with larger rockets. But there is still a major constraint on the size of objects we can get into orbit—fairing size.
This places physical constraints on the overall shape of what we can launch and severely limits the sizes of, say, a communications array or a power satellite. But a new paper from researchers at Nanjing University of Aeronautics and Astronautics and the Beijing Institute of Technology offers a solution—a self-shaping, deployable module that can fine-tune both its positioning and its own dimensions. The findings are published in the journal Space: Science & Technology.
To understand how that offers an advantage, it's best to look at how engineers currently solve this problem. Typically, they use a rollable deployable boom—a stiff, thin strip of carbon fiber that can coil up like a tape measure, then unwind to snap straight once deployed in microgravity. The problem is that these systems almost never deploy perfectly in real environments, and when talking about snapping together multiple modules, even a few millimeters of error can cause the entire mission to fail.
Fixing this requires taking steps after that initial unfolding to correct whatever errors might have been introduced. The researchers built the system as a set of three hexagonal corner pods connected by carbon-fiber rods. Each corner pod has two features—a spool and thrusters—that allow the whole assembly to adjust its sizing in real time.
Using a stepper motor to drive the spool, each module can shorten or lengthen its carbon-fiber rods on command. This not only allows it to adjust its size to the structure it intends to join, but also allows for slight adjustments, provided by a control feedback loop, to ensure that each module fits neatly into the planned structural pattern. Maneuvering the modular assembly into place is where the thrusters come in.
Each corner pod is equipped with a cold gas thruster, all connected to a central control system that uses them to nudge the module forward or backward or spin it to match the rotational speed of its intended target. Once the modules are maneuvered close enough via the thrusters, magnetic force takes over, with permanent magnets embedded in each pod that pull the modules together over the final few centimeters. This all sounds good in theory, but to prove that it is good in theory, the researchers had to develop a type of mathematical framework to combine rigid corners with bendable carbon-fiber arms, and combine that with changing masses as the module expended propellant.
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