Humanity has not yet launched a dedicated probe to another star, but the first attempts have already begun in spirit, hardware, and plans. Our earliest deep-space emissaries are drifting toward the galaxy, while ambitious concepts—from nuclear pulse rockets to laser-driven sails—chart routes we might take. Together, these missions and studies outline a practical path from the edge of our heliosphere to targeted expeditions of the nearest stars.
The Pioneer 10 and 11 spacecraft, launched in the early 1970s, were the first to escape the Sun’s grasp, each carrying a metal plaque as a greeting to any finders. Voyager 1 and 2 followed in 1977, adding the Golden Records and a richer suite of instruments. Voyager 1 crossed the heliopause in 2012 and Voyager 2 in 2018, sampling the local interstellar medium for the first time. New Horizons, launched in 2006, is also on an escape trajectory after its Pluto and Arrokoth flybys, though all four craft would take tens of thousands of years to pass near another star.
Even before those crossings, engineers sketched how a true star probe might work. Project Orion in the late 1950s proposed nuclear pulse propulsion, but atmospheric test bans and political realities halted it. The British Interplanetary Society’s Project Daedalus (1973–1978) envisioned a fusion-driven, uncrewed flyby of Barnard’s Star in about 50 years at roughly 12% light speed. NASA and the U.S.
Naval Academy’s Project Longshot (1988) later explored a smaller fusion design aimed at Alpha Centauri, highlighting daunting power and fuel requirements. The most prominent contemporary plan is Breakthrough Starshot, announced in 2016, which aims to push gram-scale “StarChip” probes to about 20% light speed using a multi‑gigawatt ground-based laser array and ultralight sails. At that velocity, a flyby of Alpha Centauri could occur roughly 20 years after launch, but the engineering hurdles are extreme. Researchers are studying sail materials, beam control, and wafer-scale spacecraft, while solar sail missions such as JAXA’s IKAROS and The Planetary Society’s LightSail 2 have demonstrated foundational technologies in space.
Communication back from several light-years away and protecting a tiny probe from dust impacts remain open challenges. A nearer-term bridge is an “Interstellar Probe” to the edge of the Sun’s influence, studied by teams in the 2020s to reach hundreds to a thousand astronomical units over several decades. Such a mission would refine fast‑escape trajectories, long‑life power systems, and autonomy—critical precursors to starflight. It would also deliver unprecedented heliophysics and astrophysics from beyond the heliosphere.
If funded, directed‑energy tests, advanced sails, and far‑out probes could, over the coming decades, mature the tools needed for the first true attempt: a targeted, relativistic flyby of the nearest stars.
