Internet investor and science philanthropist Yuri Milner and Professor Stephen Hawking have announced Starshot, a $100 million research and engineering project aiming to demonstrate proof of concept for high speed, light-propelled nanocrafts.
These could fly at 20 percent of light speed - 100 million miles an hour or a thousand times faster than the fastest space craft today. The aim is to release hundreds, or thousands, of these craft to capture images of possible planets and other scientific data - sent back by lightbeams - in our nearest star system, Alpha Centauri. While Alpha Centauri is 25 trillion miles away it would take just over 20 years for the nanocraft to reach it. In contrast, today’s fastest spacecraft would take about 30,000 years to get there.
The programme will be led by Pete Worden, the former director of NASA AMES Research Center, and advised by a committee of top scientists and engineers. The board will consist of Stephen Hawking, Yuri Milner, and Mark Zuckerberg.
Milner said the proposed gram-scale nanocraft, which is attached to a sail pushed by a light beam, embodies “the Silcon Valley approach to space travel”, capitalising on exponential advances in certain areas of technology since the beginning of the 21st century.
Milner said: “Early proposals focused on sails driven by the sun but it turns out that our own star, as big as it is, cannot produce the force required. For interstellar travel on a human time scale you need a much stronger wind and a significantly smaller boat. Only in the last 15 years three technology trends have made this possible: microfabrication, nanotechnology and photonics.”
The nanocraft comprises of two main parts: a gram-scale wafer carrying cameras, photon thrusters, power supply, navigation and communication equipment. No larger than a big stamp and not much thicker, it constitutes a fully functional space probe and can be mass-manufactured at the cost of an iPhone.
The second, a lightsail, is made possible thanks to advances in nanotechnology that can produce increasingly thin and light-weight metamaterials. This means meter-scale sails no more than a few hundred atoms thick and at gram-scale mass can now be developed.
Thanks to the rising power and falling cost of lasers the Starshot team hope to utilise phased arrays of lasers to propel the space craft. Referred to as a ‘light beamer’, it will be modular and scalable and there is potential to create one focused laser up to the 100GW scale.
Once it is assembled and the technology matures, the cost of each launch is expected to fall to a few hundred thousand dollars.
The research and engineering phase is expected to last a number of years. Following that, development of the ultimate mission to Alpha Centauri would require a budget comparable to the largest current scientific experiments such as CERN, and would involve:
-Building a ground-based kilometer-scale light beamer at high altitude in dry conditions
-Generating and storing a few gigawatt hours of energy per launch
-Launching a ‘mothership’ carrying thousands of nanocrafts to a high-altitude orbit
-Taking advantage of adaptive optics technology in real time to compensate for atmospheric effects
-Focusing the light beam on the lightsail to accelerate individual nanocrafts to the target speed within minutes
-Accounting for interstellar dust collisions en-route to the target
-Capturing images of a planet, and other scientific data, and transmitting them back to Earth using a compact on-board laser communications system
-Using the same light beamer that launched the nanocrafts to receive data from them over 4 years later.
Milner said the Starshot team have already identified and assessed a number of engineering challenges, listed on the Breakthrough Initiatives website www.breakthroughinitiatives.org, but is hopeful they can be solved.
The Starshot project is based entirely on work that is in the public domain and the team have pledging to publish all new results and welcomes contributions from experts and the public on its online forum.
Stephen Hawking, said: “With light beams, light sails and the lightest space craft ever built we can launch a mission to Alpha Centauri within a generation. Today we commit to this next great leap into the cosmos, because we are human and our nature is to fly.”