Interstellar space probes: Where’s the brakes?

With a miniaturized space probe capable of being accelerated to a quarter of the speed of light, we could reach Alpha Centauri, our nearest star, in 20 to 50 years. However, without a mechanism to slow it down, the space probe could only collect data from the star and its planets as it zoomed past. A theoretical physicist has now examined whether interstellar spacecraft can be decelerated using ‘magnetic sails’.