New initiative announced in Moscow on April 12, 2016, by Russian businessman Yuri Milner and British cosmologist Stephen Hawking seems to have potential to change the world if succeed.
It is named "Breakthrough Starshot" and is worth, according to founder, Yuri Milner $100 million. Board of the project consists of Yuri Milner, Stephen Hawking and Mark Zuckenberg; name of the program is truly well representing whole concept - first private deep space exploration program with ambitious goal - reaching star which is closest to Earth in solar system - Alpha Centauri (apart from the Sun). Mission objective seems virtually impossible in present state of technology. With present technical abilities any spacecraft with conventional propulsion will reach Alpha Centauri after 30000 years of space travel. There is also one theoretical issue - fuel. Deep space exploration spacecraft needs fuel for correcting course and for powering onboard instruments. Distance to Alpha Centauri is just too long and spacecraft would not be able to power itself during such long journey not to mention about 30000 years of engine flight. "Breakthrough Starshot" represents different and revolutionary approach to deep space exploration. It assumes using nanotechnology and solar sail propulsion. To give spacecraft appropriate speed for travelling and reaching Alpha Centauri in reasonable time, spacecraft should achieve great speed. It could be possible if spacecraft would be extremely small - with weight around few grams. Then spacecraft could use energy impulse from Earth to its solar sail to start flight and next use solar wind to achieving greater speed. This is just essential of the "Breakthrough Starshot" - at the moment it is basing on two elements: StarChip and Lightsail. First one will be microelectronic, highly integrated component built with nanotechnology and containing camera, photon thruster, power supply, navigation and communication equipment. Second, Lightsail would be main propulsion - built with ultra-thin light and extremely durable (with thickness of couple atoms) solar sail. Such spacecraft could reach Alpha Centauri in less than twenty years. According to official site of the project, it is planned to produce large number of Nano spacecrafts and lift them to orbit where they would start they journey. Solution for the communication problems, which are obviously for such long distances, will be utilizing of the Nano laser emitter for downlink.
Project due its open character is rather vision than precisely planned mission with scheduled launch date. Due the very ambitious goal there are more questions than answers - at the moment nanotechnology is not developed enough to create such spacecraft. Solar sails are still not efficient to speed up spacecraft to required speed. During such long space travel spacecraft should be highly autonomous due the great delays in communication (for example spacecraft should be able to avoid collisions with space objects for its own) and it requires numbers of sensors and thrusters for maneuvering which are not possible to be built in nanotechnology. But still it is more direction and idea than real space mission (or source of advertisement for main sponsors). Although it is worth to remind that in early thirties no one could even dream about sending man in space, but it was possible only thirty years after.
On picture above You can see vision of Breakthrough Starshot spacecraft powered with Lightsail, which receives impulse form Earth to start its journey.