Having received new orders from NASA, the still-functional Pioneer Venus Orbiter – launched in 1978 and in a high, looping orbit over Venus since it ceased active observations of the planet in 1981 – turns its instruments in the direction of Comet Encke, which is currently passing through the inner solar system. Rather than its cameras, the orbiter’s ultraviolet spectrometer is trained on the comet as Earth-based researchers try to determine the composition and rotational speed of Encke’s nucleus. The Pioneer Venus Orbiter will continue to observe other comets through the late 1980s.
