  We study the motion of a gyroscope located far away from an isolated
gravitational source in an asymptotically flat spacetime. As seen from a local
frame tied to distant stars, the gyroscope precesses when gravitational waves
cross its path, resulting in a net "orientation memory" that carries
information on the wave profile. At leading order in the inverse distance to
the source, the memory consists of two terms: the first is linear in the metric
perturbation and coincides with the spin memory effect, while the second is
quadratic and measures the net helicity of the wave burst. Both are closely
related to symmetries of the gravitational radiative phase space at null
infinity: spin memory probes superrotation charges, while helicity is the
canonical generator of local electric-magnetic duality on the celestial sphere.
