The Mars Express of the European Space Agency (ESA) shares findings on Martian moon Phobos’ solar wind interaction through a series of fake and real flybys. The backscattering of energetic particles in the Earth’s moon is also expected at Phobos, considering their similarities. Although Mars Express has already come close to Phobos several times, it had just seen the backscattering once in 2008. However, ESA researchers reported the second solar wind particles detection at Phobos during the moon’s flyby in January 2016.
Yoshifumi Futaana from the Swedish Institute of Space Physics (IRF), who is also the lead author for the paper on the 2016 flyby, noted that the relationship between Phobos and the solar wind had been an enigma. Futaana expresses the researchers’ excitement to see the signs of the reflected particles at Phobos. He questions whether the reflection comes from Phobos or Mars Express.

The fake flybys
Fake flybys are special operations performed by researchers with the spacecraft in 2017. Futaana’s co-author Mats Holmstrom describes this as a laboratory experiment conducted at Mars. The flybys allowed researchers to explore Mars Express’ influence on a solar wind in a controlled environment.
The researchers were also able to observe the solar wind interaction of Phobos. The experiment showed no signs of particle production or scattering. This suggests that the detected particles into space during the flybys in 2008 and 2016 were reflected by Phobos and not from Mars Express.

Phobos, one of the three moons in the Solar System, has always been an interest amongst the space exploration community. ESA and the Japanese Space Agency collaborated for the latter’s Martian Moons eXploration (MMX). Their mission was to explore Phobos’ origin, behavior, environment, and evolution.
ESA also aimed to identify whether the moons are debris in orbit or asteroids captured by the gravity of Mars. Aside from that, they plan to explore space to understand better the importance of charged particles’ behavior in space exploration.
YouTube: Mars Express flyby as seen from Phobos (Animation)
Photo credit: The images are owned by European Space Agency and have been provided for press usage.