Photo taken on April 12, 2016 shows the "StarChip" at the "StarShot" project press conference at One World Observatory in New York, the United States. British astrophysicist Stephen Hawking announced here Tuesday he is teaming up with Russian billionaire Yuri Milner and a group of scientists for a new "Starshot" space exploration program, which will build tiny spacecraft called "nanocrafts" capable of reaching the Alpha Centauri star system in approximately 20 years after launch. (Xinhua/Li Changxiang)