Written by Kat Kelly
Kat is a Science Facilitator at Science World and currently working towards a degree in Physics and Astronomy. When Kat isn’t gazing at the stars or sharing her love of science with our visitors, she enjoys reading, singing, playing guitar and attending public lectures and debates.

Created date

Wednesday, November 2, 2016 - 12:18pm

Breakthrough Starshot: Reaching For The Nearest Stars

In 1997 Carl Sagan said 'It will not be we who reach Alpha Centauri and the other star systems, it will be a generation much like us, with more of our strengths and fewer of our weaknesses'.

We might be that generation. Thanks to a group of dedicated individuals, a project called Breakthrough Starshot is underway. The Breakthrough Starshot plan is to reach our nearest star system, Alpha Centauri, by shooting Nano satellites, or very tiny satellites, up into space using powerful lasers

This innovative project means we may be able to get to Alpha Centauri in just 20 years.

Why Alpha Centauri

Alpha Centauri is a binary star system, meaning there are two stars orbiting each other. This star system, our closest neighbour, is 4 light years away, this means travelling at the speed of light it would take 4 years to get there. At the moment, only photons can travel at light speed, we don't have any spacecraft's that can go anywhere near that speed. 

Take the humble 'Voyager' spacecraft as an example. It launched in 1997 and has only just left our Solar System, which is further than any spacecraft has ever gone. This is a very impressive feat, but voyager is a mere 16.2 light hours away. If Voyager has left the earth when humans first arrived (around 6 million years ago), it would only just be reaching Alpha Centauri.

Another good reason to go is, Proxima b, a recently discovered exoplanet which is roughly Earth-sized and is believed to have a rocky surface just like the Earth. If we wanted to take pictures of it from Earth we would need to use a telescope that is 300km wide, when currently the largest on Earth being built is 30m wide. With the cameras on board the Nano satellites, we could take a high resolution image that would tell us information about Proxmia b's atmosphere and other possible signatures for life.

So how on Earth does Breakthrough Starshot plan to get there in 20 years?

The tiny satellites will be sent towards Alpha Centauri travelling with the momentum of millions of photons from a laser beam that gives off 60 times more light than the Earth receives at any given moment. The photons will power hundreds of tiny 1cm^3 satellites to along. Each one will have 4 cameras, communication systems, navigation and power supplies all included and will be attached to a Light Sail.

Since space is a vacuum, there is nothing, no air, no dust In between the stars and planets. Nothing. this means that once you push something, like a photon, off in a certain direction, it will just keep going forever. There is nothing to slow it down.

We can use the momentum of photons from the laser just like a boat sail uses the wind to propel it forward. Using this technique, these spacecraft will travel at 20% the speed of light - 1 million times faster than a car on the highway.

Who are the people behind the project?

The board of directors for Breakthrough Starshot will shoulder the $100 million cost of the project. The members of the board are:

Ann Druyan - Carl Sagan's wife and creative director of 'Cosmos' and the voyager missions

Yuri Milner - Founder of DST Global (Digital Sky Technologies)

Stephen Hawking - Famous Physicist and author

Lawnrence Krauss - Famous Physicist and author

Mark Zuckerberg - CEO and Founder of Facebook

Lou Friedmann - JPL and the Planetary Society

Freeman Dyson - Princeton Institute of Advanced Study

Cool Fact: The satellites themselves each cost less than an iPhone 6.

Want to learn more about Nano technology, the cost of space explorationthe speed of light or Lightsail then check out more of our SWOGs and visit our current feature gallery , Zoom in to Nano!



I understand that you want to

I understand that you want to inspire the next generation to dream big but teaching science includes teaching a scientific way of thinking, which one of caution and skepticism. In science, you have to be careful to not allow yourself to be blinded by wishful thinking. Let's consider this proposal with healthy skepticism. Lubin’s roadmap laid out myriad obstacles that any laser-propelled interstellar mission would have to overcome, such as linking many smaller lasers into a kilometer-scale array and engineering lightweight, gossamer-thin sails strong enough to endure the array’s gigawatt-scale pulses as well as persuading policy makers to allow the construction of a laser system that could in principle be used as a weapon. The probes will also need to transmit observations back to Earth using onboard lasers with just a few watts of power—a problem potentially solvable by using the giant Earthbound laser array as a receiver. But the biggest obstacle of all was simply a matter of cost: At an estimated present-day price of approximately $10 per watt of laser power, building and operating Breakthrough Starshot’s 100-gigawatt array today could cost as much as $1 trillion. Though laser technology is advancing quickly, it’s hard to envisage what material these nanocraft will be constructed from. Even if their laser sails reflected the majority of the laser energy that hits them, there’s going to be a huge heating problem. To be frank, the nanocraft would be incinerated by the hypothetical 100 gigawatt propulsion laser if the heat isn’t efficiently radiated. But to radiate heat, the nanocraft would need radiators, which will add to the nanocraft mass. Assuming these nanocraft can be launched and sent beyond the solar system, they will need to be extremely durable and bundled with failsafes. But 20 years is a long time in space and though the interstellar medium pretty empty by solar system standards, should these craft hit anything, even the tiniest grain of dust along its 20 year path could impact any component like a hypervelocity bullet smashing into a bone china teacup. Let’s not forget that these things will be traveling at 20 percent the speed of light — that’s over 130 million miles per hour. Although they are small, will they also need shielding? Probably, but this will once again increase their weight, ultimately slowing them down. 1. Lack of Funding Even though Yuri Milner has announced that he will be investing $100 million in Breakthrough Starshot, in the field of space exploration and technology, this is still not enough. Stephen Hawking and his team need to raise more money, billions even, just to suffice the technology they will use to reach Alpha Centauri. Using the current system available, it would take 80,000 years to complete the trip. However, Stephen Hawking and his team are planning to speed up the process by 100 million miles an hour, claiming that the system that they will be using will reach Alpha Centauri in just 20 years. If this is the case, this means that the big leap from 80,000 years to 20 years equates to bigger funding. The recent probe to Pluto already cost $720 million, making the $100 million from Yuri Milner just a small chip of the whole project. 2. Dangers of Using a Powerful Laser Breakthrough Starshot requires one big laser to catapult the tiny robotic probes to space. The laser is both powerful and dangerous because it requires 100 gigawatts. With that gigantic amount of power, it could fry anything that's obstructing its way like satellites. 3. Obstacle in Communication and Maintenance Because the tiny robotic probes will be light years away, this means that when something needs to be fixed, the distress signals will reach Earth after a long time. If this happens, alerting the team on Earth and sending back help will cost a lot of years, resulting in uncertainty if the malfunctioning probe will even be fixed or has died already. 4. Without Data Transmission, It's Pointless Considering the probe's minuscule size, it's still a challenge for Stephen Hawking and the whole Breakthrough Starshot team to find a way to implant a communication and data-gathering device into the probes, which can send data and images back to Earth. Lastly, I have to point out an error in this article. The human species evolved 200,000 years ago, not 6 million years ago.

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