As Voyagers 1 and 2 continue their epic journeys through interstellar space, they're resolving past controversies and even helping to spark a new one: the true shape of the heliosphere. Launched more than four decades ago, the two Voyager spacecraft keep expanding our horizons. Having flown past the giant planets in the late 1970s and 1980s, Voyagers 1 and 2 are now well beyond all their planetary targets, with Voyager 1 more than five times farther out than Neptune and Voyager 2 not far behind. “Every day is a new record for Voyager,” says the spacecraft’s project manager, Suzanne Dodd at the Jet Propulsion Laboratory near Los Angeles, CA. New data from the fabled Voyager spacecraft have fed a controversy over the geometry and activity of the heliosphere. Image credit: NASA/JPL-Caltech. “I never in my wildest dreams thought that I would still be working on Voyager fifty years after we wrote the proposal,” says Voyager researcher Stamatios “Tom” Krimigis of Johns Hopkins University in Laurel, MD. During the past decade, both spacecraft reached a new realm, entering the interstellar medium: the tenuous material that fills the vast space between the stars. There, the spacecraft continue to make new discoveries. The interstellar magnetic field has surprised researchers with both its strength and its direction, and the new data have even fed a controversy over the geometry and activity of the heliosphere—the Sun’s magnetic domain. Is the heliosphere the shape of a comet, as has long been assumed, or is it instead more spherical? And does it expand and contract when sunspots wax and wane, or is it more stable? The spacecraft have offered up some tantalizing clues. Voyager 2 left Earth in 1977, followed by Voyager 1. They weren’t the first spacecraft to reach the nearest of the giant planets—that honor …