Our ambitions in space exploration have seen humans land on the moon, rovers explore Mars, and spacecraft venture to the outer reaches of our solar system. But can we reach Alpha Centauri, the closest star system to Earth, located about 4.4 light-years away? This system, home to three stars, including Proxima Centauri, which hosts an exoplanet potentially habitable, presents a monumental challenge.
Using a space shuttle like NASA’s Discovery, the journey to Alpha Centauri would take nearly 150,000 years. Even traveling at the speed of light, it would take four years, a feat impossible for anything with mass. However, smaller spacecraft, designed to travel at a fraction of the speed of light, might reach these stars within a human lifespan.
To achieve such speeds, scientists are exploring the use of swarms of picometer-sized spacecraft, much smaller than the Voyagers. These tiny spacecraft, being less powerful, can be accelerated more easily. This concept is being investigated by startups like Space Initiatives Inc, as well as initiatives like Breakthrough Starshot, which aims to combine nanometer-sized spacecraft with light sails.
While smaller spacecraft are easier to accelerate, traditional fuel sources aren’t powerful enough to push them near light speed. Instead, scientists are looking to light-powered propulsion, using either solar sails or photonic sails. These sails, propelled by the sun’s or laser light, are massless, giving them a significant advantage over traditional rocket fuel. The momentum carried by light transfers to the spacecraft, accelerating it.
Although technology for such tiny spacecraft, like communications equipment, is still in development, there are no physical limitations preventing a flyby mission to Alpha Centauri. This mission, similar to the Voyager probes, could transmit high-resolution images of the star system, potentially revealing Proxima Centauri’s habitable planet.
While the journey to Alpha Centauri is a long-term endeavor, scientists are optimistic about advancements in the coming decades. Small probes could launch in the 2040s, reaching Alpha Centauri by the 2060s. Larger probes might be possible by the end of the century, but crewed missions likely remain a challenge for the next century.
