Although the planets have usually been the destinations of space probes, minor members of the Solar System have not been ignored. In March 1986, several space probes passed near Bailey's Comet as it approached Earth.
Two Russian probes, Vega 1 and 2, approach within 5,520 and 4,990 miles ( 8,890 and 8,030 km) respectively on 6 and 9 March. Although the images from their cameras were blurry, onboard spectrometers successfully measured the composition of the comet's dust.
Four days later, the European Space Agency's probe, Giotto, intercepted Halley's Comet. It penetrated the coma, or head, of the comet, passing within 370 miles (600 km) of the nucleus and sending back astonishing images of bright geyser-like jets erupting from a black potato-shaped body. The composition and mass of the coma and the dust tail were measured, as was the interaction between the comet's gas and the solar wind. Halley's solar-wind interactions were further studied by the International Sun-Earth Explorer and the Japanese probes Sakigake and Suisei.