BepiColombo keeping an eye on Earth from afar

A sequence of daily images of Earth taken by the joint European-Japanese BepiColombo spacecraft as it moved away from our planet after its gravity-assist flyby on 10 April 2020, on its path towards the inner Solar System and its final destination, Mercury. The first image in this sequence was taken on 13 April, 1.3 million km away, and the last image on 5 May, around 8 million km away.

The images were captured by one of the MCAM selfie cameras mounted on the Mercury Transfer Module (MTM), one of the three components of the BepiColombo mission. One of the solar arrays is visible on the upper side of the images, and the structure visible in the lower right corner at the beginning of the sequence is one of the sun sensor units on the MTM, covered in multi-layered insulation.

Planet Earth is visible at the centre of the images, below the solar panel, first as a pale crescent, then gradually fainter until barely visible. A version of this animation with a zoomed and brightened inset showing Earth is available here. The images have been cropped and corrected for brightness; the original frames are available on ESA's Planetary Science Archive, along with other MCAM images that do not feature Earth.

These images complement the views of Earth gathered by BepiColombo as it approached, closed in, and departed from our planet on 9–11 April, which are also combined in a timelapse video of the flyby.

The orbit-tightening manoeuvre, which saw BepiColombo come as close as 12 689 km to Earth’s surface at 04:25 UTC on 10 April, provided an opportunity to test several instruments and sensors aboard the two science orbiters that comprise the mission, ESA’s Mercury Planetary Orbiter (MPO) and Mio, the Mercury Magnetospheric Orbiter of the Japanese Aerospace Agency (JAXA).

Data gathered during the flyby, including observations of the Moon from the MERTIS instrument and measurements of Earth's magnetic field by the MPO-MAG magnetometer, and data recorded by the Italian Spring Accelerometer (ISA), demonstrate that the instruments are in excellent condition to gather high-quality data during the spacecraft’s long cruise, even before reaching Mercury, the mission's target, with arrival scheduled in late 2025.

The Earth flyby was the first of nine gravity-assist manoeuvres that BepiColombo, launched in October 2018, will perform during its seven-year journey. BepiColombo will perform its next two flybys at Venus and further six at Mercury.