Last year, the Russian billionaire Yuri Milner committed to spending $100 million on “Breakthrough Starshot,” a massive engineering project with the intention of developing a fleet of miniature spacecraft capable of travelling to our nearest neighboring star system, Alpha Centauri — some 20 to 30 years away from Earth travelling at less than a quarter the speed of light.
One of the most tantalizing aspects of travelling to Alpha Centauri is investigating its Proxima Centauri B exoplanet, which possesses an Earth-like mass and orbits within the system’s habitable zone — meaning that it has the potential to harbor life. So far, so good.
The problem is getting the data back from the lightweight solar sail that Breakthrough Starshot aims to send. Radio, for instance, is impossible. An independent astrophysicist named Michael Hippke thinks he has a solution, however — and he’s published a couple of papers online to explain what it might entail. The TLDR version? It involves using an effect called gravitational lensing and the sun’s gravity to amplify signals from the probe for some sweet interstellar space streaming.
“In the first paper of my series, I show that we can communicate with such a probe near Proxima at low data rates, in the vicinity of bits per second, when using large Earth-based telescopes,” Hippke told Digital Trends. “This allows for the transfer of a few images over the course of months, but nothing more. In the second paper, I analyze how to improve the data rate. This can be done using our sun as a telescope. The gravitational field bends the light and a telescope can be put in its focus to collect the signal photons. This allows for much higher data rates.”
According to Hippke’s calculations, the gravitational lens telescope could increase data rate by a factor of one million. That would mean data transfer rates sufficient for live HD video streaming. (“Although live is relative,” he points out. “The speed of light still applies, and it takes the photons 4 years for the journey.)
The coolest part of Hippke’s suggestion is that it uses a lot of existing technology — although it still requires the use of a spacecraft being launched further into space than any we’ve launched before.
“The receiver itself it off-the-shelf established technology,” he said. “A telescope like the Hubble Space Telescope would be totally sufficient in terms of aperture and quality. It would need to be equipped with a coronagraph, also standard technology, and a fast photon detector. The difficult part is to bring the device, which would be 1 to 2 meters, to to a distance of 600 astronomical units — roughly the distance from Earth to the Sun — which takes many decades with classical rockets. However, there are some NASA studies that show options for gravitational swing-bys and high-velocity rockets to make it possible in 30-50 years.”
Plus, there’s that tiny matter of getting a probe near to Proxima in order to send us the data in the first place, of course!