Starshot update

Two years ago I wrote about a project called Breakthrough Starshot, which proposed sending small remote-controlled cameras to nearby star systems, powered by lasers that could propel them up to twenty percent of the speed of light.

Which means we could be getting photographs back from Proxima Centauri in twenty years.

[Image licensed under the Creative Commons ESO/M. Kornmesser, Artist's impression of the planet orbiting Proxima Centauri, CC BY 4.0]

It's an ambitious project, and faces significant hurdles.  Even if propelled by lasers -- which, being light, travel at the speed thereof -- navigation becomes increasingly difficult the farther away it gets.  Even at the distance of Pluto, our intrepid little spacecraft would be 4.5 light-hours from Earth, meaning if we tried to beam it instructions to dodge around an incoming meteor, it would be 4.5 hours until the command arrived, at which point all that would be left is intrepid scrap metal.  And Proxima Centauri is 4.3 light years away.

You see the problem.  The Starshot spacecraft would have to be able, on some level, to think for itself, because there simply wouldn't be time for Mission Control to steer it to avoid danger.

There are other obstacles, though.  Besides the obvious difficulties of being in the cold vacuum of interstellar space, contending with cosmic rays and the like, there's the problem engendered by its speed   Assuming the estimate of a maximum velocity of twenty percent of light speed is correct, even tiny particles of dust would be formidable projectiles, so Starshot is going to require some heavy-duty shielding, increasing its mass (and thus the amount of energy needed to make it go).

But last month we got an encouraging proof of concept, when the group working on the mission -- Russian entrepreneur Yuri Milner's Breakthrough Foundation -- launched a test of the Starshot craft.  It was a tiny little thing, small enough to fit in your hand and weighing about the same as a stick of gum, designed and built by engineers at the University of California - Santa Barbara, and in the test flight achieved an altitude of nineteen miles, all the while functioning flawlessly, returning four thousand images of the Earth taken from aloft.

The Breakthrough Foundation is planning a suborbital test next year, and perhaps a full orbit the year after that.  So things are moving along.  But the most significant hurdle is to design the laser system to make Starshot move -- lasers that are so finely collimated that they can still strike a ten-centimeter craft square-on from several light years away.  The engineering director for Breakthrough, Peter Klupar, is designing a 100,000 gigawatt laser -- to be located, he says, in Chile -- that could be the answer.  Of course, such a powerful device is not without its dangers.  Reflected off a mirror in space, Klupar says, such a laser could "ignite an entire city in minutes."

Not that there's a mirror out there.  So you shouldn't worry at all about that.

"You would think that this is all impossible, but we have folks at Caltech and the University of Southampton and Exeter University working on about 50 contracts on making all [of] this happen," Klupar said.  "No one has come up with a deal-breaker that we can find yet. It all seems real."

One possible way to increase the thrust generated by the laser is to increase the surface area that the beam strikes, and Klupar thinks he knows how to do that -- using a "light sail."  He's already built a prototype.  "The sail is very thin. It's about 400 atoms thick, it weighs about a half a gram, and it's four meters in diameter," he said.  "I think of it as 'reflective smoke.'"

All of which may seem like science fiction, but it's phenomenal how fast things go from the realm of Star Trek to reality.  Klupar compares his light sails to CubeSats, tiny (ten by ten centimeters, weighing a little over a kilogram) orbiting telemetry devices that are now common.  "It feels a lot like the way CubeSats felt twenty years ago," he said.  "People were saying, 'Those are toys, they're never going to develop into anything, there's no way I can see that ever working.'  And today and look them: Hundreds of millions of dollars is being spent on them."

So keep your eye on this project.  If there's a chance at a remote visit to another star system, I think this is our best bet.  The Breakthrough Foundation estimates an actual, honest-to-goodness launch toward a nearby star as early as 2030.  Meaning perhaps we could get our first photographs of planets around another star by 2050.

I'll be ninety years old at that point, but if that's what I'm waiting for, I can make it till then.

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When the brilliant British neurologist and author Oliver Sacks died in August of 2015, he was working on a collection of essays that delved into some of the deepest issues scientists consider: evolution, creativity, memory, time, and experience.  A year and a half ago, that collection was published under the title The River of Consciousness, and in it he explores those weighty topics with his characteristic humor, insight, and self-deprecating humility.

Those of us who were captivated by earlier works such as The Man Who Mistook His Wife for a Hat, Musicophilia, Awakenings, and Everything in its Place will be thrilled by this book -- the last thoughts of one of the best thinkers of our time.

[Note:  If you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Reaching for the stars

It has long been one of my dearest wishes to have incontrovertible evidence of extraterrestrial intelligence in my lifetime.  I've been a staunch supporter of SETI; in fact, my screensavers both at home and at work are from "SETI at Home," which pilfers a little bit of the computing power of computers that are on but not currently being used to analyze signals from the Arecibo Radio Telescope for signs of extraterrestrial communications.  My classroom walls have lots of ET-related stuff, including a poster from the Roswell UFO Museum, a sky map showing the location of various exoplanets, and Fox Mulder's "I Want To Believe" UFO poster.

Unfortunately, though, SETI has thus far come up empty-handed, and the accounts of UFO sightings have been, one and all, beneath the threshold of evidence that most of us science-minded types would be willing to accept.  And honestly, it's unlikely that ET, should it exist, has come here.  The distances involved are simply too big.  The same barrier (even more unfortunately) prevents us from going there.  Until Zefram Cochrane invents the warp drive, we're pretty much Solar System-bound.

But that doesn't mean we can't explore -- we just have to find a different way.

One of the most intriguing ones I've seen I had never heard of until yesterday.  Called "Breakthrough Starshot," this is an initiative to send unmanned probes out using the idea of a light sail -- a lightweight craft propelled by light pressure -- to Proxima Centauri, the nearest star to the Sun, which just last year was shown to have an exoplanet of its own.  The Breakthrough Starshot site says:

In the last decade and a half, rapid technological advances have opened up the possibility of light-powered space travel at a significant fraction of light speed.  This involves a ground-based light beamer pushing ultra-light nanocrafts – miniature space probes attached to lightsails – to speeds of up to 100 million miles an hour.  Such a system would allow a flyby mission to reach Alpha Centauri in just over 20 years from launch, beaming home images of its recently-discovered planet Proxima b, and any other planets that may lie in the system, as well as collecting other scientific data such as analysis of magnetic fields. 

Breakthrough Starshot aims to demonstrate proof of concept for ultra-fast light-driven nanocrafts, and lay the foundations for a first launch to Alpha Centauri within the next generation.

The cool thing about this is that it removes not only the distance barrier, but eliminates one of the biggest concerns -- which is how, even if we could achieve the kinds of speeds Breakthrough Starshot talks about, we could protect the crew of a manned mission from the effects of being in space for that long.  Just a few weeks ago, a study of identical twins Mark and Scott Kelly showed that Scott, who had just come back from a year aboard the International Space Station, had significantly less bone density than his brother.  (Scott also showed a slight lowering of cognitive function, but it is uncertain if that was an effect of the mission.)

So it's pretty certain that long-term space travel will result in some fairly major changes in metabolism and bodily function, not to mention the psychological strain of being cooped up for years on a spacecraft millions of miles away from terra firma.  The idea that we could get the information we're looking for remotely, without risking human life, is pretty exciting.

Breakthrough is also sponsoring two other programs besides Starshot:

Breakthrough Listen is a $100 million program of astronomical observations in search of evidence of intelligent life beyond Earth. It is by far the most comprehensive, intensive and sensitive search ever undertaken for artificial radio and optical signals. A complete survey of the 1,000,000 nearest stars, the plane and center of our galaxy, and the 100 nearest galaxies. All data will be open to the public. 

Breakthrough Message is a $1 million competition to design a message representing Earth, life and humanity that could potentially be understood by another civilization. The aim is to encourage humanity to think together as one world, and to spark public debate about the ethics of sending messages beyond Earth.

Of the three, however, Starshot is the most exciting to me.  Just the idea that we might, in my lifetime, receive digital images of a planet revolving around another star is one of the most thrilling things I can think of.

So keep your eye on the Breakthrough Project.  It sounds like they're going about things the right way, and that this might be our best hope for finding out if we have neighbors.

Until Zefram Cochrane comes along, of course.  After that, screw being here, I'm going boldly where no one has gone before.