Airships are dusty relics of aviation history. Lighter-than-air vehicles conjure images of the Hindenburg, in its glory and destruction, and the Goodyear Blimp, a floating billboard that barely resembles its powerful predecessors.

But now engineers are designing sleek new airships that could streak past layers of cloud and chart a course through the thin, icy air of the stratosphere, 65,000 feet above the ground — twice the usual altitude of a jetliner. Steered by scientists below, these aerodynamic balloons might be equipped with onboard telescopes that peer into distant galaxies or gather oceanic data along a coastline.

“Stratospheric airships could give us spacelike conditions from a spacelike platform, but without the spacelike costs,” said Sarah Miller, an astrophysicist at the University of California, Irvine.

High-altitude airships are still in their relative infancy. None has ever flown at 65,000 feet for longer than eight hours. But a recent study from the Keck Institute for Space Studies at Caltech suggests that a more capable airship may not be far-off. And NASA is expected to sponsor a contest to build better airships, breathing new life — and funding — into the idea.