All propulsion systems that leave the Earth are based on chemical reactions with a few adding ion engines. Chemical reactions, at best, have an efficiency compared to rest mass of 10-9 (or about 1eV per bond). All the mass in the universe converted to chemical reactions would not propel even a single proton to relativistic speeds. While chemistry will get us to Mars, it will not allow interstellar capability in any reasonable mission time. Barring new physics, we are left with few solutions, other than science fiction and imaginary propulsion. Recent advances in photonics and directed energy systems now allow us to realize the possibility of relativistic flight. With spacecraft from fully-functional gram-level wafer-scale systems ("wafer sats") capable of speeds greater than c/4 that could reach the nearest star in 20 years to spacecraft for large missions capable of supporting human life with masses more than 105 kg (100 tons) for rapid interplanetary transit that could reach speeds of greater than 1000 km/s can be realized. With this technology spacecraft can be propelled to speeds currently unimaginable. Photonics, like electronics, and unlike chemical propulsion is an exponential technology with a current double time of about 20 months. It is this that is the key. In addition, the same photon driver can be used for many other purposes such as planetary defense, space debris vaporization and de-orbiting, beaming energy to distant spacecraft, beaming power for high Isp ion engine missions, asteroid mining, sending power back to Earth for high value needs, stand-off composition analysis, long range laser communications, SETI searches, kilometer class telescopes among others. This would be a profound change in human capability, one whose non-scientific implications would be enormous. Known as Starlight, NASA began our Phase I funding in April 2015. On April 12, 2016 the Breakthrough Foundation announced that they would support this effort with a 100M$ Research and Development program called Breakthrough Starshot that would explore the fundamental technology underlying this. On May 12, 2016 NASA announced Phase II funding. On May 23 the FY 2017 congressional appropriations request directs NASA to study the feasibility of an interstellar mission to coincide with the 100th anniversary of the moon landing using quoting our NASA program as one option. I will discuss the idea of relativistic flight generally, the many technical challenges ahead, our current laboratory prototypes and data as well as the transformative implications of this program.
APPLIED PHYSICS/PHYSICS COLLOQUIUM
Held Tuesdays at 4:30 pm in the William R. Hewlett Teaching Center, room 200. Refreshments in the lobby of Varian Physics at 4:15 pm.
Winter 2016/2017, Committee: A. Linde (Chair), S. Kivelson, S. Zhang