By Matthew Willis April 19, 2016
Alpha Centauri has been the subject of greater public attention since the announcement of Breakthrough Starshot on April 12. A Breakthrough Initiative created by Russian billionaire Yuri Milner, Starshot aims to develop a gram-scale spacecraft to fly by the nearest star system. Accelerated via light sail to speeds in excess of 50,000 km/s, the probe will traverse the 4.3 lightyears to Alpha Centauri in less time than the Voyager probes took to reach the edge of our Solar System.
The Starshot announcement was closely followed by the Breakthrough Discuss workshop held at Stanford on April 15-16. The workshop brought together forward-thinking scientists and engineers, including SLAB’s principal investigator Prof. Simone D’Amico and collaborator Prof. Bruce Macintosh, to open a dialog on the next steps in our exploration of the cosmos. Discussion centered around long-term programs such as expanding the Search for Extra-Terrestrial Intelligence (SETI), application of the upcoming Extremely Large Telescopes (ELTs) to search for planets at Alpha Centauri, and the positioning of a space telescope at the focal distance of the Sun’s gravitational lens. Into this discourse, Prof. Macintosh introduced the Miniaturized Distributed Occulter/Telescope (mDOT), a near-term mission concept that can deliver valuable scientific data while paving the way for flagship missions.
The mDOT concept developed by Prof. D’Amico leverages SLAB’s expertise in formation flying and the low-cost of micro- and nano-satellites to effectively demonstrate technologies required for large-scale occulter/telescope missions, such as NASA’s proposed New Worlds Observer (NWO). These missions will use a precisely-positioned occulter spacecraft to block the light from a target star so that the space telescope can observe the star’s immediate vicinity. As initially conceived, mDOT would provide evidence for the structure of planetary systems around distant stars by imaging their exozodiacal dust. A slightly up-scaled version of mDOT would open the possibility of directly imaging extrasolar planets in the Alpha Centauri system. Astrometric observations suggest that there are no gas giant planets orbiting Alpha Centauri’s two sun-like stars, leaving the exciting prospect of finding Earth-size planets in the stars’ habitable zones. Discovery of such a world in our neighbor system by mDOT would drive the development of Starshot, galvanize observation efforts by the ELTs and future space telescopes, and capture the public imagination for generations to come.