Only 200 kilometers: On a cosmic scale, that’s nothing. At that distance, the European-Japanese spacecraft Bepicolombo flew above Mercury’s cratered surface. Technically, this maneuver is called a “hover”: a path close to a planet.
This move was one of many maneuvers needed to get the spacecraft into orbit around the planet. The team on the ground immediately seized the opportunity to take some photos. The first one came online on Thursday.
“Amazing,” space expert Eric Lan calls the new image. “We rarely see Mercury this close,” he adds. Only two of the two probes precede the Bepicolombo.
gravity
Traveling to Mercury is very difficult due to its proximity to the Sun. It pulls a probe with a greater gravity than a small planet like Mercury. In order to stay close to the planet, Bepicolombo must slow down very precisely. This happens during a flyby, as the probe gives some of its velocity to the planet.
Thursday’s flight was its second, and there are four more on the agenda before the probe remains permanently trapped in Mercury’s gravity. Bepicolombo takes its name from Giuseppe “Bebe” Colombo, the man who first charted this complex journey in 1979.
Spacecraft that fly close to the sun must withstand extreme temperatures. On the day side of Mercury, the temperature rises above 400 degrees Celsius, while on the shadow side Mercury can dip well beyond 100 degrees below freezing. To ensure the probe continues to operate during such high fluctuations, Bepicolombo uses a type of titanium blind that reflects sunlight and can fold inward or outward to regulate heat.
puzzles
Although such a flyby is only a fleeting encounter between the probe and the planet, it is a precious moment for new measurements to be made, Johannes Benkoff, project scientist at Bepicolombo, said in a press release. We welcome any analogy to solve the mysteries of Mercury, questions such as: How do planets so close to stars form? And how can a small planet generate a magnetic field?
Bepicolombo will be in orbit around Mercury in three years, after which it will spend about a year collecting measurement data – and more images.
