TARS: Sunlight-Powered Space Slingshot Could Propel Tiny Probes to the Stars

Scientists have long dreamed of sending tiny spacecraft to other stars, but the challenge remains immense. A new idea called TARS (Torqued Accelerator using Radiation from the Sun), named for the robot in Interstellar, aims to turn fiction into reality by harnessing sunlight as a slingshot. TARS is essentially a solar-powered centrifuge: two long reflective panels on a tether that spin and fling a tiny probe outward at high speed. Unlike rockets or giant lasers, this design needs no exotic fuel, only sunlight and engineering.

Solar-Powered Space Slingshot

According to the paper published in arXiv, the design of TARS by Kipping, professor of astronomy at Columbia University, uses two reflective panels on long booms, forming a giant rotating slingshot in space. Sunlight pushes on the shiny sides of these panels (much like a solar sail), causing the whole system to spin faster and faster.

After months or years of rotation, a small probe attached to the edge is released like a stone from a sling. In one example, 7-meter-wide panels spun for three years could fling a probe at about 7.5 miles (12 km) per second, enough to escape the Sun's gravity with orbital boost.

Voyage to the Stars

Even at about 0.3% of light speed, it would take over a thousand years to reach Alpha Centauri (4.3 light-years away). Kipping notes such voyages are inherently multi-generational, a “progressive” endeavor. He notes even engineering students could build a prototype.

This simplicity has drawn attention: one team offered a free launch if someone builds a cubesat-scale prototype. This sun-powered slingshot joins other ambitious ideas—like laser-driven lightsails—to explore whether tiny probes can one day reach the stars. Kipping argues every idea is worthwhile, since “some combination of them will get us to the stars.”