Inside a Billionaire’s New Interstellar Mission

[SolarpunkFan]

http://www.theatlantic.com/science/arch ... ri/477669/

Yuri Milner is spending $100 million on a probe that could travel to Alpha Centauri within a generation—and he's recruited Mark Zuckerberg and Stephen Hawking to help. In an interview with ​The Atlantic, Milner makes his case for star travel.

In the Southern Hemisphere’s sky, there is a constellation, a centaur holding a spear, its legs raised in mid-gallop. The creature’s front hoof is marked by a star that has long hypnotized humanity, with its brightness, and more recently, its proximity.

Since the dawn of written culture, at least, humans have dreamt of star travel. As the nearest star system to Earth, Alpha Centauri is the most natural subject of these dreams. To a certain cast of mind, the star seems destined to figure prominently in our future.

In the four centuries since the Scientific Revolution, a series of increasingly powerful instruments has slowly brought Alpha Centauri into focus. In 1689, the Jesuit priest Jean Richaud fixed his telescope on a comet, as it was streaking through the stick-figure centaur. He was startled to find not one, but two stars twinkling in its hoof. In 1915, a third star was spotted, this one a small, red satellite of the system’s two central, sunlike stars.

Astronomers are now looking for planets around all three.

To say that Alpha Centauri is the nearest star system to Earth is not to say that it’s near. A 25 trillion mile abyss separates us. Alpha Centauri’s light travels to Earth at the absurd rate of 186,000 miles per second, and still takes more than four years to arrive.

Aerospace engineers have spent decades trying to push spacecraft to extreme speeds, and with great success. The New Horizons probe that just whistled by Pluto is our fastest flying spaceship. It can cover more than one million miles per day. But if we aimed New Horizons at Alpha Centauri, it would reach the star tens of thousands of years from now. Interstellar travel with existing propulsion technology is all but unimaginable.

But, new technology might be on the way.

Interesting, but I'm going to be cautious with my optimism.

[Khaat]

The required jump from theory to practical is the rub: where is that jump going to come from?

It's a shame the article isn't about the actual program so much as the target star system. Hawking's contribution is theoretical physics, Zuckerberg's is ... pop/media? Is the program's goal to "crowd-research" the practical?

Throwing money at it might get actual progress, or lay the foundations for getting actual progress, but it will mean wading through tons of crap.

[Simon_Jester]

100 million is waaaay too low to begin to budget for an interstellar probe. If it's based on radical new drives that can get there quickly, that's not enough money to build the engine. If it's based on conventional rocketry, then even assuming nothing changes in the next 25000 years or whatever, it's not enough money to make sure that future people keep listening to the probe, even assuming the probe doesn't fail, which it would.

[Ziggy Stardust]

I'm fairly certain that this money is going to be distributed through grants to various researchers to investigate whether this type of propulsion system can be practically developed. None of the quotes I read from Hawking et al suggested they thought that they were going to start building one with this money, but rather they want to kick-start the process of people actually trying to design one. I can't find the quote now, but the first story I read on the mission quoted Milner as not necessarily expecting this to even happen within his own lifetime but thinks that it is important for the future of space travel that they use this money to begin the process of thoroughly investigating the potential of the concept.

[SpottedKitty]

The TV reports I saw appeared to be trying (with varying success) to describe something similar to Robert Forward's Starwisp concept from 30-odd years ago. Admittedly, nanoprobes with tiny sails pushed to 0.2c by monster lasers or masers hit all my "Ooh! Shiny!" buttons...

[Starglider]

There are a lot of technical challenges on the list to which the answer is 'it has not been conclusively proven to be impossible'. The communication challenge in particular is dubious; they mention some potentially applicable research about low-power communication from lunar distances, but scaling that to interstellar distances with a 100mg power supply is entirely speculative.

[Zeropoint]

I am all for this, because I want to live in a world where Stephen Hawking is a supervillain holding the world hostage with a giant space laser cannon.

[Guardsman Bass]

This is pretty cool stuff, although some of the technical challenges are daunting. The probe has to survive and function after an acceleration of 25,000 gs, for example.

[SpottedKitty]

This is pretty cool stuff, although some of the technical challenges are daunting. The probe has to survive and function after an acceleration of 25,000 gs, for example.

Maybe not quite as bad as all that; the whole thing will probably be solid-state with no moving parts, so it can be ruggedised to an extent you can't get with anything needing mechanical parts. One of the major issues is likely to be fragility, because the sail material is going to have to be gossamer-thin, and any wobble in the laser launcher's beam will cause massive forces across the width of the sail. Definitely some advances in materials science needed there.

On the gripping hand, something like an artillery shell is only smacked really hard for a fraction of a second; this thing's flight profile will need thrust times of weeks, if not months.

[GrandMasterTerwynn]

This is pretty cool stuff, although some of the technical challenges are daunting. The probe has to survive and function after an acceleration of 25,000 gs, for example.

Maybe not quite as bad as all that; the whole thing will probably be solid-state with no moving parts, so it can be ruggedised to an extent you can't get with anything needing mechanical parts. One of the major issues is likely to be fragility, because the sail material is going to have to be gossamer-thin, and any wobble in the laser launcher's beam will cause massive forces across the width of the sail. Definitely some advances in materials science needed there.

On the gripping hand, something like an artillery shell is only smacked really hard for a fraction of a second; this thing's flight profile will need thrust times of weeks, if not months.

Actually, they're planning to kick it up to 0.20C in about two minutes using a ~100 gigawatt phased-laser array. That's why everyone's saying the probe has to withstand many tens of thousands of gees.