Thursday, 22 June 2017

Why Interstellar Travel Will Be Possible Sooner Than You Think

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.



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 technologiesare 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.

1. 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 01 May 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.

2. 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.

3. 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.

4. 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.

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.

5. 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.

6. Energy Storage

While the Starchip will use a tiny nuclear-powered radioisotope battery for its 24-year-plus journey, we will still need conventional chemical batteries for the lasers. The lasers will need to employ tremendous energy in a short span of time, meaning that the power must be stored in nearby batteries.

7. Lasers
Thousands of high-powered lasers will be used to push the lightsail to extraordinary speeds.

8. Speed
Achieving 20% speed of light for Starshot would represent a 1000x speed increase for any human-built object.

9. Memory Storage

Fundamental to computing is the ability to store information. Starshot depends on the continued decreasing cost and size of digital memory to include sufficient storage for its programs and the images taken of Alpha Centauri star system and its planets.

10. Telecommunication
Once the images are taken the Starchip will send the images back to Earth for processing.

The bandwidth and speed required for Starshot to send digital images over 4 light years—or 20 trillion miles—will require taking advantage in the latest telecommunications technology.One promising technology is Li-Fi, a wireless approach which is 100 times faster than WIFI. 

11. Computation

The final step in the Starshot project is to analyze the data returning from the spacecraft. To do so we must take advantage of the exponential increase in computing power, benefiting from the  trillion-fold increase in computing over the 60 years.

All for now,
+Brad Skelton