European Space Agency listening

Days after the European Space Agency [ESA] released the first pictures of its historic dual flyby of Venus, the space agency has now recorded sounds emerging from the planet as the Solar Orbiter and the BepiColombo spacecraft crossed the mysterious planet.

The ESA-NASA Solar Orbiter spacecraft flew past Venus on August 9 at a distance of 7,995 km, while the ESA-JAXA BepiColombo mission skimmed past at just 552 km fplanetrom the s surface a day later. The two spacecraft used Venus to slingshot their way to the centre of the Solar System.

While the Solar Orbiter is headed to the Sun, the BepiColombo spacecraft is on its way to study the innermost planet of the solar system Mercury, where it is expected to make the first of six flybys on October 1-2 before entering orbit in 2025. Meanwhile, the solar orbiter will make a close Earth flyby on November 27, "before further Venus slingshots will tilt its inclination in order to get the first-ever views of the Suns poles," ESA said.

Sounds of Venus

During their gravity assist, the spacecraft recorded the sounds of Earth's mysterious twin as they headed towards their destinations. The sounds have been generated from the planets gravity acting on the spacecraft structure and its response to the rapid temperature changes.

The Italian Spring Accelerometer [ISA] onboard the BepiColombo spacecraft recorded the accelerations measured by the spacecraft, which was then translated into the frequency to make them audible. ESA said that the accelerometer also felt the tidal effects acting on the spacecraft as it flew at different distances past Venus.

Another audio generated from a simple sonification captures low-frequency wind-like noises caused by the solar wind and its interaction with Venus.

Feeling the Venutian heat

During the flyby, the BepiColombo spacecraft felt a major surge of heat on its structures as it flew as close as 552 km from the planets surface. The heat rose as the spacecraft passed from the nightside to the dayside of the planet. Mercury Magnetospheric Orbiter [MMO] recorded an increase of 110 degrees Celsius on one of its eight solar panels. The temperature change ranged from -100 degrees Celsius to 10 degrees Celcius.

"On the European Mercury Transfer Module, a temperature increase of 50 degrees was observed on the spacecraft radiator, while the Mercury Planetary Orbiter [MPO] recorded a change of about 20 degrees," ESA said.

Both spacecraft felt the immense gravitational pull of the planet on their reaction wheels, which are used to maintain the spacecraft's attitude, keeping it pointing on course. The spacecraft also experimented with the magnetic field of the planet with the Solar Orbiter magnetometer team describing noticing a spike in magnitude due to the compression of the field as they travelled past the flanks of the planet.

"Sensors on both BepiColombo MPO and MMO were also monitoring for ions circulating in the magnetosphere and in the close vicinity of Venus," the agency said.

Earlier the space agency had released a picture taken by the Mercury Transfer Modules Monitoring Camera 3, which captured a black-and-white snapshot of Venus in 1024 x 1024 pixel resolution. The solar orbiter did not click any picture of Venus since the science cameras onboard the spacecraft must remain facing the Sun.