Road to Mercury: flyby with Earth

A flyby is close passage of a space probe, at high speed, near a planet or other celestial object. It can be used to speed up or slow down the space probe.

The first successful planetary flyby ever made was performed the 14th December 1962 by the Mariner 2 NASA spacecraft with the planet Venus, but it was with the Mariner 10 mission, thanks to an intuition of the italian Mathematician Giuseppe Colombo in 1970, that we use now the flyby as orbital correction maneuver. Indeed, the professor from Paduan was invited from the JPL to participate in a conference about the Mariner 10 directed to Mercury. When he observed the spacecraft computed orbit, he noted that the Mariner 10 would have an orbital period around the sun twice the Mercury year. Hence, he suggested to carfully calibrate the first passage over Mercury in such a way that the spacecraft would have exactly the delta velocity from the planet to re-encounter Mercury at the next revolution. His suggestion was fully accepted and, thanks to him, Mercury 10 (llaunched in the 1973 on its way to Venus) had its first flyby with Mercury on 5th February 1974, and a second a third flyby on 21th September 1974, and also a third on 16th March 1975. The change in trajectory found by Giuseppe Colombo allowed to greatly increase the scientific return of the mission, as well as the scientific knowledge of the planet Mercury.
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On the early morning of the 10th of April, there will be the possibility, hopefully, to observe the crossing on the sky of BepiColombo spacecraft crossing the sky from East to West. The closest approach is foreseen at 04.25 UTC with a minimum distance of 12.677 km from the Earth's surface.

If you want to compute your own plot for your location by inserting latitude and longitude here: https://bepicolombo.iaps.inaf.it.

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source: esa