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Breakthrough Starshot Faces Material Science and Engineering Challenges

posted by Fnord666 on Wednesday May 09 2018, @03:21PM   
from the new-type-of-sailing-vessel dept.

takyon writes:

Researchers have written about some of the challenges involved in building a light sail suitable for Breakthrough Starshot, a project that would accelerate a gram-scale "chipcraft" using lasers so that it could travel interstellar distances in just decades:

A team of researchers at the California Institute of Technology has taken a hard look at the challenges facing efforts to carry out the Breakthrough Starshot project. In their Perspective piece published in the journal Nature Materials, the researchers outline the obstacles still facing project engineers and possible solutions.

The light sail would need to be made of a lightweight but reflective material able to withstand being bombarded by gigawatts of photons without melting. Graphene doesn't qualify. Many of the materials the researchers evaluated have only been studied in their bulk forms, rather than thin films, which can have different properties.

The researchers seem optimistic about the challenges. From the abstract (DOI: 10.1038/s41563-018-0075-8) (DX):

The Starshot Breakthrough Initiative established in 2016 sets an audacious goal of sending a spacecraft beyond our Solar System to a neighbouring star within the next half-century. Its vision for an ultralight spacecraft that can be accelerated by laser radiation pressure from an Earth-based source to ~20% of the speed of light demands the use of materials with extreme properties. Here we examine stringent criteria for the lightsail design and discuss fundamental materials challenges. We predict that major research advances in photonic design and materials science will enable us to define the pathways needed to realize laser-driven lightsails.

Also at Ars Technica.

Previously: Stephen Hawking and Yuri Milner's $100 Million Interstellar Spacecraft Plan

Related: NASA Plans to Launch an Interstellar Mission to Alpha Centauri in 2069

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Original Submission

• Re:communications? (Score: 5, Informative) by takyon on Wednesday May 09 2018, @04:51PM

  by takyon (881) <takyonNO@SPAMsoylentnews.org> on Wednesday May 09 2018, @04:51PM (#677498) Journal

  https://www.popsci.com/three-questions-for-breakthrough-starshot [popsci.com]

  Breakthrough Starshot currently envisions sending gram-scale star-chips each using a 1-watt laser to communicate with Earth. Can such tiny lasers could effectively transmit data back to Earth? The project says that it has a solution.

  To receive the data from each probe, the project proposes that the laser array that launched the star-chips will also serve as a large "phased array" telescope, one sensitive enough to receive laser signals from each miniature spacecraft. The array is composed of many transmitters, each emitting at infrared or near-infrared wavelengths. It would not be difficult to make each element of the array a receiver as well as a transmitter.

  The probes can also use the reflective sails they rely on for propulsion as mirrors, to help focus their lasers for communications back to Earth.

  To help compensate for glare from Alpha Centauri and other stars that might swamp out the light signals from star-chips, each probe will use a very narrow-bandwidth laser — essentially, a light with a very distinctive color, one that researchers will be able to distinguish from all the other lights in the sky.

  Lubin calculates that each star-chip might be capable of transmitting data straight back to Earth at a rate of nearly a kilobit per second. In addition, there are other strategies the project may follow to improve data transmission. For instance, Breakthrough Starshot does not plan to send just one probe to Alpha Centauri — it might launch an armada of thousands, one after the other. "You could imagine a bucket brigade, with one probe sending data back to another, which sends it back to another," Lubin says. "That's much more complex though, since they each have to figure out where the other probes are, and not the preferred solution."

  If they did use electromagnetic communications instead, newer radio telescopes could use interferometry. They could be based in different locations in space, or on the Moon.

  https://www.nextbigfuture.com/2017/04/planet-wide-millimeter-radio-telescope.html [nextbigfuture.com]

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