Breakthrough Starshot Project: Could Relativistic Spacecraft Make it to Alpha Centauri?

The Breakthrough Starshot initiative aims to launch gram-scale spacecraft to a speed of v~0.2c, capable of reaching Alpha Centauri and seeing the Earth-like exoplanet, Proxima b, from close distance, in about 20 years. However, a critical challenge for the initiative is the effects of interstellar matter and magnetic field to the relativistic spacecraft during the journey. In this talk, I will first present our evaluation for the damage to the spacecraft by interstellar gas and dust based on a detailed analysis of the interaction of a relativistic spacecraft with the ISM. Second, I will discuss the deflection and oscillation of spacecraft by interstellar magnetic fields. Third, I will discuss the gas drag fore at high energy regime and quantify its effect on the slowing down of the relativistic lightsails. Finally, we will discuss practical strategies to mitigate the damage by interstellar dust and to maintain the spacecraft aiming at the intended target.