Why Interstellar Travel Will Be Possible Sooner Than You Think

 
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Image Credit: Breakthrough Starshot
The term “moonshot” is sometimes invoked to denote a project so outrageously ambitious that it can only be described by comparing it to the Apollo 11 mission to land the first human on the Moon. The Breakthrough Starshot Initiative transcends the moonshot descriptor because its purpose goes far beyond the Moon. The aptly-named project seeks to travel to the nearest stars.
 
The brainchild of Russian-born tech entrepreneur billionaire Yuri Milner, Breakthrough Starshot was announced in April 2016 at a press conference joined by renowned physicists including Stephen Hawking and Freeman Dyson. While still early, the current vision is that thousands of wafer-sized chips attached to large, silver lightsails will be placed into Earth orbit and accelerated by the pressure of an intense Earth-based laser hitting the lightsail.

After just two minutes of being driven by the laser, the spacecraft will be traveling at one-fifth the speed of light—a thousand times faster than any macroscopic object has ever achieved.

Each craft will coast for 20 years and collect scientific data about interstellar space. Upon reaching the planets near the Alpha Centauri star system, an the onboard digital camera will take high-resolution pictures and send these back to Earth, providing the first glimpse of our closest planetary neighbors. In addition to scientific knowledge, we may learn whether these planets are suitable for human colonization.
 
The team behind Breakthrough Starshot is as impressive as the technology. The board of directors includes Milner, Hawking, and Facebook co-founder Mark Zuckerberg. The executive director is S. Pete Worden, former director of NASA Ames Research Center. A number of prominent scientists, including Nobel and Breakthrough Laureates, are serving as advisors to the project, and Milner has promised $100 million of his own funds to begin work. He will encourage his colleagues to contribute $10 billion over the next several years for its completion.
While this endeavor may sound like science fiction, there are no known scientific obstacles to implementing it. This doesn’t mean it will happen tomorrow: for Starshot to be successful, a number of advances in technologies are necessary. The organizers and advising scientists are relying upon the exponential rate of advancement to make Starshot happen within 20 years.
Here are 11 key Starshot technologies and how they are expected to advance exponentially over the next two decades.

Exoplanet Detection

An exoplanet is a planet outside our Solar System. While the first scientific detection of an exoplanet was only in 1988, as of May, 1 2017 there have been 3,608 confirmed detections of exoplanets in 2,702 planetary systems. While some resemble those in our Solar System, many have fascinating and bizarre features, such as rings 200 times wider than Saturn’s.

The reason for this deluge of discoveries? A vast improvement in telescope technology.
Just 100 years ago the world’s largest telescope was the Hooker Telescope at 2.54 meters. Today, the European Southern Observatory's Very Large Telescope consists of four large 8.2-meter diameter telescopes and is now the most productive ground-based facility in astronomy, with an average of over one peer-reviewed, published scientific paper per day.

Researchers use the VLT and a special instrument to look for rocky extrasolar planets in the habitable zone (allowing liquid water) of their host stars. In May 2016, researchers using the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile found not just one but seven Earth-sized exoplanets in the habitable zone.

Meanwhile, in space, NASA’s Kepler spacecraft is designed specifically for this purpose and has already identified over 2,000 exoplanets. The James Webb Space Telescope, to be launched in October, 2018, will offer unprecedented insight into whether exoplanets can support life. “If these planets have atmospheres, [JWST] will be the key to unlocking their secrets,” according to Doug Hudgins, Exoplanet Program Scientist at NASA headquarters in Washington.

Launch Cost

The Starshot mothership will be launched aboard a rocket and release a thousand starships. The cost of transporting a payload using one-time-only rockets is immense, but private launch providers such as SpaceX and Blue Origin have recently demonstrated success in reusable rockets which are expected to substantially reduce the price. SpaceX has already reduced costs to around $60 million per Falcon 9 launch, and as the private space industry expands and reusable rockets become more common, this price is expected to drop even further.

The Starchip

Each 15-millimeter-wide Starchip must contain a vast array of sophisticated electronic devices, such as a navigation system, camera, communication laser, radioisotope battery, camera multiplexer, and camera interface. The expectation we’ll be able to compress an entire spaceship onto a small wafer is due to exponentially decreasing sensor and chip sizes.

The first computer chips in the 1960s contained a handful of transistors. Thanks to Moore’s Law, we can now squeeze billions of transistors onto each chip. The first digital camera weighed 8 pounds and took 0.01 megapixel images. Now, a digital camera sensor yields high-quality 12+ megapixel color images and fits in a smartphone—along with other sensors like GPS, accelerometer, and gyroscope. And we’re seeing this improvement bleed into space exploration with the advent of smaller satellites providing better data.

For Starshot to succeed, we will need the chip’s mass to be about 0.22 grams by 2030, but if the rate of improvement continues, projections suggest this is entirely possible.

The Lightsail

The sail must be made of a material which is highly reflective (to gain maximum momentum from the laser), minimally absorbing (so that it is not incinerated from the heat), and also very light weight (allowing quick acceleration). These three criteria are extremely constrictive and there is at present no satisfactory material.

The required advances may come from artificial intelligence automating and accelerating materials discovery. Such automation has advanced to the point where machine learning techniques can “generate libraries of candidate materials by the tens of thousands,” allowing engineers to identify which ones are worth pursuing and testing for specific applications.

Read more on SingularityHub.

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