Researchers with the UCSB Experimental Cosmology Group (ECG) reached a major milestone by successfully testing a prototype version of system carried by a high altitude balloon. They plan to continue improvements and eventually have a laser-propelled interstellar StarChip spacecraft.
UC Santa Barbara students sent up, via balloon, a prototype miniature spacecraft that might eventually become the “wafercraft” that researchers posit could be propelled by lasers to achieve space travel at relativistic speeds to reach nearby star systems (Proxima Centauri) and exoplanets within our lifetimes.
Under the leadership of Philip Lubin, the group has dedicated a considerable amount of effort towards the creation of an interstellar mission consisting of directed-energy light sail and a wafer-scale spacecraft (WSS).
The prototype StarChip wafercraft that was tested by the UCSB Experimental Cosmology Group. Credit: UCSB
The prototype wafer scale spacecraft (WSS) is small enough to fit in the palm of one hand. It was launched into the stratosphere above Pennsylvania, to an altitude of 105,000 feet (32 km) — three times that of commercial aeroplanes — to gauge its functionality and performance.
The project’s goal, as the device’s name suggests, is to build an ultra-lightweight (gram scale) silicon wafer with embedded electronics, capable of being shot into space while relaying data back to Earth. For the distance the researchers want to achieve — roughly 25 trillion miles, or 40 trillion kilometres, cruising at a significant fraction of the speed of light — the technology required is daunting.
The launch was conducted in collaboration with the United States Naval Academy in Annapolis on April 12th, 2019. This date was selected to coincide with the 58th anniversary of Russian Cosmonaut Yuri Gagarin‘s orbital space flight, making him the first human to go to space.
For the sake of this flight, the science team that created it put the StarChip through a series of tests designed to gauge its performance in space and ability to explore other worlds. Aside from seeing how it fared in Earth’s stratosphere (three times higher than the operational ceiling of aeroplanes), the prototype collected more than 4000 images of the Earth.
The idea behind the StarChip is simple. By taking advantage of advancements in miniaturisation, all the necessary components of an exploratory mission could be mounted on a spacecraft the size of a human hand.
“Due to the rapid advancements in microelectronics we can shrink a spacecraft into a much smaller format than has been done before for specialised applications such as ours.” said Nic Rupert, a development engineer in Lubin’s lab.
The sail component builds on the concept of a solar sail and developments made with lightweight materials; and together, they add up to a spacecraft that could be accelerated up to 20% the speed of light.
How will the 'StarChip' get to it's destination?
Considering the distances involved – 4.24 light years (40 trillion kilometres; 25 trillion miles) – and the fact that the spacecraft will need to reach a fraction of the speed of light, the technological requirements are daunting.
Ordinary chemical propulsion, such as that which took us to the moon nearly 50 years ago to the day, would take nearly one hundred thousand years to get to the nearest star system, Alpha Centauri.
“Even an advanced propulsion such as ion engines would take many thousands of years. There is only one known technology that is able to reach the nearby stars within a human lifetime and that is using light itself as the propulsion system" Lubin said.
Known as directed energy propulsion, the technology requires building an extremely large array of lasers to act as the propulsion. This system does not travel with the spacecraft; it remains on Earth.
"If you have a large enough laser array, you can actually push the wafers with a laser sail to get to our goal of 20 percent of the speed of light," added Rupert. "Then you'd be at Alpha Centauri in something like 20 years."
One of the greatest challenges at this point is building an Earth-based laser array that would be capable of accelerating the laser sail.
Initial Wafer Scale Spacecraft Prototype Model A (left), Model B (middle), Model D (right) and a US Quarter
Part of a NASA-funded endeavour called Starlight, the effort is supported also by the Breakthrough Foundation, where it is known as Starshot. UC Santa Barbara initiated the project in 2009 with modest funding from NASA’s Spacegrant program, receiving additional funds in 2015 via NASA Advanced Concepts.
The UC Santa Barbara team then approached billionaire tech investor Yuri Milner’s Breakthrough Foundation in 2016 to share the implications of the technology. In April of that same year, the foundation announced it would undertake a $100 million effort to back this program.