What lies beyond our solar system has long fascinated not just scientists but also writers and filmmakers, so murky are its depths.

Now, Canberra researchers say they have cracked the code to enable us to send a spacecraft even further, and at a far greater speed, to another planetary system altogether.

The spacecraft is also so small and delicate that scientists plan to send more than one in the hope that some of them will make it to Alpha Centauri, without being destroyed by an errant piece of space dust along the way.

The achievement is "Very exciting" because it could enable us to record information from those planetary bodies within our lifetime — its predicted travel time is just 20 years.

Compare that to the roughly 44 years Voyager 2 spent nosing around Uranus and Neptune before continuing into interstellar space.

The study's lead author, Australian National University astrophysicist Chathura Bandutunga, said when they discovered the solution it was a kind of "Eureka moment", when they worked out how many lasers, and in what formation, they would need to propel their spacecraft far enough and fast enough to reach its goal.

"We already have several crafts — Voyager included — [in interstellar space] but it will be many human lifetimes before they reach anywhere near another star," Dr Bandutunga said.

"For the Breakthrough Starshot probe to reach Alpha Centauri within one lifetime it will need to travel over 2000 times faster than our current interstellar probes."

A sail, shot with lasers

Dr Bandutunga said the whole project was "Very ambitious", but one researchers were finally confident enough to share with their collaborators around the world.

"The challenge that we're really looking at is how do we use light to push the satellite along?" he said.

"And how do we get that light from a ray that's on the ground all the way to the satellite in orbit? How to do that on a grand scale that's really unheard of to date."

If their theory is correct, the lasers will be arranged in just the right combination and number to propel the sail to where it needs to go, and the next step is to test that theory within the laws of physics.

"The next step is to test the building blocks in a laboratory setting," he said.

Ideally, a spacecraft will reach Alpha Centauri, the closest star system and closest planetary system to Earth's, and record images and scientific measurements that will be broadcast back to Earth.

Scientists estimate roughly 100 million individual lasers will be needed to generate the required optical power of about 100GW.

Fellow author Paul Sibley said the devil was in the detail when it came to unscrambling the lasers.

"We use a random digital signal to scramble the measurements from each laser and unscramble each one separately in digital signal processing," he said. 

“This allows us to pick out only the measurements we need from a vast jumble of information. We can then break the problem into small arrays and link them together in sections."

While these measurements may seem confounding to the average eye, what is clear is that scientists have never got this close before.

"This project is really about making that travel from our star to another star possible within a human lifetime," Dr Bandutunga said.

Story By | Niki Burnside