Breakthrough Starshot wants to go to Alpha Centauri

On the anniversary of Yuri Gagarin’s maiden space flight, Yuri Milner who was named after Gagarin announced plans to fund a fleet of tiny space craft to Alpha Centauri, the star system closest to the sun. Ars Technica reports  the star studded launch on top of World Trade Center, included popular science science author, theoretical physicist and cosmologist Stephen Hawking, physicist and mathematician Freeman Dyson who is famous for conceptualizing the Dyson sphere, as well as Ann Druyan, the co-writer of PBS documentary series Cosmos. New Horizons, the fastest spacecraft built so far would take 80 years to cover the distance, Breakthrough Starshot hopes for a new approach which will cover the distance in 20 years. Breakthrough Starshot hopes to use a ground based laser, called a light beamer to propel a fleet of small spacecraft weighing only grams. The spacecraft will be equipped with lightsails, which work similar to the sails on sailboats, only they will be pushed forward by photons and not wind. The sail component also doubles as the antenna for communications with earth. The nanocraft have all the components of a spacecraft embedded on one chip, called a StarChip, which will beam back photos and scientific readings once it reaches its destination. Each nanocraft has 4 photon thrusters, 4 cameras, 4 batteries and a protective coating. Challenges to work around include a small and light power generation and storage unit, wear and tear of the sail because of interstellar dust and precisely determining the orbital position of an exoplanet.