ALL SCI-FI

[Gord Green]

Back in April, Russian billionaire Yuri Milner pledged US$100 million toward a crazy plan to visit another star system.

The mission - Breakthrough Starshot - aims to get this done by propelling teeny, tiny spaceships to 20 percent the speed of light with powerful lasers.

Milner and famed physicist Stephen Hawking initially said their destination would be Alpha Centauri: a star system located some 4.37 light-years (25.7 trillion miles) away from Earth.

But the recent and groundbreaking discovery of a nearby planet could switch things up for Starshot.

Astronomers on Wednesday announced they'd discovered an Earth-like and potentially habitable world, called Proxima b, circling Proxima Centauri - a red dwarf star that's even closer than Alpha Centauri by about 1 trillion miles (1.61 trillion km).

The discovery provides an obvious target for a flyby mission, Avi Loeb, a physicist at Harvard University and a Starshot mission advisory committee chair, wrote in an email to Business Insider.

A spacecraft equipped with a camera and various filters could take colour images of the planet and infer whether it is green (harbouring life as we know it), blue (with water oceans on its surface) or just brown (dry rock).

The team hopes to achieve a launch in two to three decades, says Loeb, and reach Proxima Centauri about 20 years later. The photos, meanwhile, would take at least 4.24 years - the distance in light-years from here to the star - to get back to Earth.

Adding up that timeline, Starshot thinks it could take photos of Proxima b (plus whatever else its nanocraft encounter there) by the year 2060.

How to sail to a star

Milner said in April that Starshot will start out as a US$100 million engineering proof-of-concept to design, build, launch, and propel a small fleet of iPhone-size nanocraft to Alpha Centauri in about 25 years time.

Each nanocraft will contain a tiny spacecraft and a laser-light sail for propulsion. This is the Silicon valley approach to spaceflight, Milner said.

The hypothetical spacecraft, called StarChip, will be built out of a gram-scale silicon wafer that's carrying cameras, photon thrusters, power supply, navigation and communication equipment, and constituting a fully functional space probe.

Moving each StarChip along will be a Lightsail propulsion unit.

An array of powerful lasers called a beamer will take aim at the Lightsails, accelerating each nanocraft to more than 215 million km/h (134 million mph).

A sense of urgency to reach Proxima b

At this point, Starshot already has a prototype for the StarChip. It's smaller than an iPhone, and it will be backed with cameras, photon thrusters, power supply, navigation, and communication equipment.

But Loeb said the next five to 10 years of the project - and most of the $100 million - will be focused on proving the laser propulsion idea actually works.

From there they will work on perfecting the tiny ships, Loeb said, noting that a beamer could potentially launch hundreds of cheap, gram-scale spacecrafts per year.

"This will allow us to send a fleet of probes towards Proxima that could relay the images taken back to Earth more easily (from one spacecraft to the next along the line of sight to Proxima)," he said.

Noting that existing telescopes can't photograph the new planet, Loeb added: "The curiosity to know more about the planet (most importantly whether it hosts life) will give the Starshot initiative a sense of urgency."

Even if it doesn't support life, Loeb says it's still important to explore the not-so-distant world.

"The lifetime of Proxima is several trillion years, almost a thousand times longer than the remaining lifetime of the Sun," he said. "Hence, a habitable rocky planet around Proxima would be the most natural location to where our civilisation could aspire to move after the Sun will die, 5 billion years from now."

Read more:http://www.sciencealert.com/this-russian-billionaire-has-a-plan-to-travel-to-proxima-b-our-closest-earth-like-planet

[Bud Brewster]

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Good video about Project Starshot.

___ The Breakthrough Starshot mission explained


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Is there no man on Earth who has the wisdom and innocence of a child?
~ The Space Children (1958)