The joint European and Russian mission to Mercury, BepiColombo, has captured a last image of Earth as it makes a final flyby of our planet.
The image was taken by one of BepiColombo’s “selfie” cameras, which are mounted on the Mercury Transfer Module. The three cameras take black and white images of 1,024 × 1,024 pixels in resolution, and are used to monitor the status and integrity of parts of the craft including the solar array and the Mercury Planetary Orbiter.
This particular image shows the Earth, illuminated against the black of space, with the moon just barely visible as a tiny speck above the end of the solar array. In the bottom left you see one of the sun sensors on the Mercury Transfer Module. The image was taken from over 300,000 miles away from Earth, after the spacecraft swung around our planet to get a gravity assist this week as it headed out into the solar system toward its target of Mercury.
The joint European-Japanese Mercury spacecraft BepiColombo took a final glimpse of Earth on the 11th of April, 2020, a day after its closest approach to the planet to perform a gravity-assist flyby. ESA/BepiColombo/MTM, CC BY-SA 3.0 IGO
BepiColombo will investigate Mercury using its two orbiting spacecraft, the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO). One of the biggest questions that the mission aims to investigate is how Mercury formed, as it is a very small planet and travels very close to the sun. Astronomers think that it may have formed elsewhere in the solar system and moved into its current position at a later time.
The planet also has an unusually large core in relation to its size, which could indicate a dramatic history. “One theory is that this big impact in the past, in addition to possibly pushing Mercury to where it is today, also stripped away most of the crust material and left behind the dense core with only a thin outer layer,” Johannes Benkhoff, ESA BepiColombo Project Scientist, explained in a statement.
Artist’s impression of BepiColombo orbiters arriving at Mercury. ESA
The mission will also search for water on Mercury as, surprisingly, despite the surface temperatures of up to 450°C, the previous MESSENGER mission to the planet spotted what might be water ice around its poles. “We have strong indications that there might be water ice in these craters, but it has not been detected directly,” Johannes said. “With the instruments that we have on MPO, we hope to be able not only to measure water content directly and confirm whether there really is water but also to attempt to find out how much of it is there.”
BepiColombo is scheduled to arrive at Mercury in December 2025.