Interstellar travel may not be lightyears away.
Breakthrough Starshot, an international research project, recently provided an update on its plans to send a probe to Alpha Centauri, our nearest neighboring star system.
Before that, it will have to develop and test a new type of spacecraft propulsion system that uses a lightsail and a laser beam array to achieve the enormous speeds required for interstellar travel within our lifetimes, according to an Australian National University (ANU) press release.
A 40 trillion kilometer journey through space
Breakthrough Starshot’s ultra-lightweight spacecraft will have to travel four light-years to reach Alpha Centauri. To put it another way, our nearest neighboring star system is a mind-shattering 40,208,000,000,000 (40 trillion) km away from Earth.
As a point of reference, today’s fastest and most reliable technology for long-distance space travel is the ion thruster, which is propelling NASA’s DART mission to a nearby asteroid at speeds of 15,000 mph (24,000 km/h). However, NASA estimates that using an ion thruster would take 18,000 years, or approximately 2,700 human generations, to reach Alpha Centauri.
The Breakthrough Starshot team believes
that by using lasers on Earth, its spacecraft will be able to travel the distance to Alpha Centauri in only 20 years. If the probe spacecraft does reach its destination, it will return the first-ever images taken from another solar system, providing a never-before-seen window into distant planets that may or may not resemble Earth.
The ANU team outlined their concept in a new research paper, which is designed to make travel to Alpha Centauri a feasible proposition. The team is working on a tiny probe with a lightsail that will be powered by an Earth-based laser array. Throughout its interstellar journey, the laser array will focus millions of beams on the sail, allowing it to reach incredible speeds.
“To cover the vast distances between Alpha Centauri and our own solar system, we must think outside the box and forge a new way for interstellar space travel,” Dr. Bandutunga, from the Applied Metrology Laboratories at the ANU Centre for Gravitational Astrophysics, explains.
“Once on its way, the sail will fly through the vacuum of space for 20 years before reaching its destination. During its flyby of Alpha Centauri, it will record images and scientific measurements which it will broadcast back to Earth.”
Interstellar spaceflight powered by 100 million lasers
Breakthrough Starshot and the ANU team rely on the advancement of several key technologies to develop their spacecraft. Lightsails, for example, has only recently been demonstrated to be a viable mode of space travel. LightSail 2, a Carl Sagan-inspired project, successfully lifted its orbital trajectory around Earth by 3.2 kilometers in 2019 using a lightsail, or solarsail, propelled by photons from the Sun.
The main challenge, however, will be the ANU team’s cutting-edge laser array proposal, which will require precisely training millions of lasers to work in unison. “The Breakthrough Starshot program estimates the total required optical power to be about 100 GW — about 100 times the capacity of the world’s largest battery today,” Dr. Ward, from the ANU Research School of Physics, says. “To achieve this, we estimate the number of lasers required to be approximately 100 million.”
To keep their lasers pointing precisely at the lightsail for the duration of the journey, the ANU team proposes using a ‘guide laser’ satellite in Earth’s orbit, which will act as the conductor, making sure the entire laser array is pointing at the right coordinates. This, alongside an algorithm designed to pre-correct the light from the array, will help to account for the atmosphere distortion the rest of the Earth-bound lasers will suffer.
Breakthrough Starshot is one of Yuri Milner’s Breakthrough Initiatives, a set of scientific and technological efforts aimed at finding life outside our solar system. If the lightsail prototype is successful, it might reach the planets around our closest star, Alpha Centauri, during our lifetime. The project’s success would thereby raise humans to the status of interstellar species.
READ MORE: Scientists Have Created A Star Trek-Like Plane That Flies Using “Ion Thrusters” And No Fuel
