The Telescopes of the Future Might Assemble Themselves in Space
The scientist behind the Modular Active Self-Assembling Space Telescope Swarm wants to make space telescopes less risky and more productive.
The impulse to build stuff that “forms like Voltron” isn’t just fodder for 1980s animated series and hip hop lyrics. Across multiple scientific fields, the idea of engineering small components that can link up together to create massive structures has become a hot topic.
One of the coolest examples of these architectures is the Modular Active Self-Assembling Space Telescope Swarm, a proposal that was recently greenlit for funding and development by the NASA Innovative Advanced Concepts (NIAC) Program.
Envisioned by Cornell University aerospace engineer Dmitry Savransky, this space telescope would be composed of thousands of hexagonal modules that would be dropped off in space by several rocket launches over months or even years. Once off Earth, the modules would deploy solar sails to propel them to a target location, meet up with the other parts, and autonomously arrange themselves into a telescope with a diameter of at least 30 meters.
A space telescope of this scale could revolutionize astronomical observation, enabling scientists to pinpoint the evolution of stars and galaxies over a timespan of 10 billion years, gaze at exoplanets in unprecedented detail, and pursue unresolved questions about dark matter and energy.
“I wanted to study the modular, self-assembling space telescope concept because there are incredible science cases for giant space telescopes,” Savransky explained in an email. “But existing techniques for building telescopes on the ground and then launching them in one piece simply won't scale to the giant aperture sizes that future astronomers will need.”
Indeed, this approach is a contrast to the traditional method of bundling progressively more complex space telescopes into just one nail-baiting launch. An example is NASA’s next-generation James Webb Space Telescope (JWST), currently slated for liftoff in 2020 after several delays, which comes with an $8.8 billion price tag. It would not be surprising if JWST scientists occasionally wake up from anxiety dreams about one launch flaw destroying such a valuable project. With Savranksy’s modular self-assembling model, however, these risks are mitigated.
“There are a lot amazingly talented people working on [JWST], and the delays that we've seen are basically a demonstration of how hard it is to build something like this,” he said. “I wanted to explore a method for constructing future space telescopes where we could actually mass-produce components, where failure in any one launch couldn't lead to the failure of the entire mission, and where we could even think about expanding an updating existing structures on orbit.”
In addition to lowering the odds of mission-ending catastrophes, the modular design of this new telescope concept makes it potentially scalable to sizes that would be impossible to launch in one go. Observatories on this colossal scale of 30 meters are still in the making on Earth, so it would be a boon to figure out a mechanism to send them to space.
“A 30-meter diameter telescope would have a collecting area roughly 30 times larger than James Webb, and roughly 150 times larger than Hubble,” Savransky said. “This means that even with instrumentation that has the same spatial and spectral resolutions as JWST and Hubble instruments, we could perform observations in minutes that would take many days or even months with the smaller telescopes.”
This all sounds mind-blowing in theory, but the hard part will be determining its feasibility. Now that he has been awarded Phase I funding from NIAC, which is normally in the range of $125,000, Savransky and his team will model sequences of deployments and rendezvous, and analyze whether a high-quality mirror structure could be functionally assembled from smaller parts. He also wants to figure out if the solar sails could double as sunshields for the telescope, or be repurposed as a long-term source of solar power.
No doubt it will take several years and lots of creative thinking to answer these questions. But speculatively speaking, if all the kinks were to be worked out, this model of space telescope would drastically improve our understanding of the universe beyond Earth. Perhaps its most exciting potential superpower would be the ability to “capture high signal-to-noise measurements of light reflected from exoplanets” during their rotation periods, Savransky said.
“This will allow us to deduce the fraction of different types of ground cover, such as land, water, and ice, on an Earth-like exoplanet,” he told me. “We might even be able to say, for the nearest such exoplanets, whether they have continents and oceans like Earth's.”
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