In July 1976, NASA's Mariner 10 flew through a comet's tail. This flyby marked the first successful exploration of a comet and showed how the solar wind influences cometary structure. One unexpected and unexplained observation from the spacecraft, however, remained a scientific mystery—a 192% spike in meteoroid impacts on the spacecraft the day after flying though the coma (gas and dust envelope) of Halley's Comet.

Researchers have determined these high impact rates were associated with an unknown meteor stream that the spacecraft fortuitously encountered about 24 hours after it passed through the comet.

They found a small dust trail that is part of a previously uncataloged complex of meteoroid streams associated with comet C/1975 V1 (West). It's called the 'West Meteoroid Stream Complex.' Based on their dynamical investigation, West meteoroids encountered near Comet Halley at 0.92 astronomical units from the Sun were associated with two peaks: the first one on July 8 and the second and most pronounced maximum observed the following day by the spacecraft. Researchers used numerical simulations to model those encounters by linking the observations by Mariner 10 to past and future orbits resulting from non-gravitational forces acting on dust particles to calculate their trajectories to determine an association.

Comet West approached the center of the Sun between April and May 1976 with the dust trail created over many previous orbits, likely due to the fragmentation of parent bodies in multiple cometary apparitions, the authors said. "This is another piece of evidence which shows the complex dynamical nature of dust trails produced by splitting comets," concluded researcher Humberto Campins in an email with Inside Outer Space. "We can expect new meteor streams coming close by to Earth after a breakup as happened before when comets 2P/Encke and 41P/Tuttle-Giacobini-Kresak produced streams with a similar history in terms of creation time or duration over which these trails took place."