BepiColombo Mercury Mission: Gravity Assists, Orbit Insertion, and Solar Wind Science

Overview

The Science Museum video provides an accessible tour of Mercury exploration, focusing on the BepiColombo mission as a joint ESA–JAXA effort to advance beyond NASA's Messenger and the historic Mariner 10 flybys. It explains why orbiting Mercury offers a fuller understanding of the planet and outlines the stacked spacecraft design and key scientific goals.

It also highlights a real-world setback: in April 2024 the mission experienced thruster power issues, delaying arrival from December 2025 to November 2026, and it showcases how engineering teams adapt to such challenges. The video closes with a nod to the Bepe Colombo structural thermal model on display in the gallery and the engineering story behind mission readiness.

Introduction to Mercury and the BepiColombo mission

Mercury is the closest planet to the Sun and among the least explored in our inner solar system. The video introduces BepiColombo, a collaboration between the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA), designed to build on data from NASA’s Messenger mission and the older Mariner 10 flybys. The goal is to obtain a comprehensive picture of Mercury, including its interior, surface, and magnetic field, by placing orbiting spacecraft around the planet rather than relying on flybys alone.

Historical context and earlier missions

NASA's Messenger arrived at Mercury in 2011, following Mariner 10's flybys in the 1970s that mapped about half of Mercury’s surface and detected a faint atmosphere. Messenger provided richer data and raised new questions about Mercury, which BepiColombo aims to address. The video emphasizes how successive missions have progressively expanded our understanding of the planet and its interactions with the solar wind.

BepiColombo architecture and mission timeline

The mission comprises a stacked three-vehicle formation: at the bottom is the Mercury Transport Module, in the middle is the European Mercury Planetary Orbiter (MPO), and on top is the Japanese Mercury Magnetospheric Orbiter (MMO). After arrival at Mercury, the two orbiters will separate to travel in their distinct orbits: the MPO will study Mercury’s interior and composition, while the MMO will observe Mercury’s magnetic field and its interaction with solar wind and solar storms. BepiColombo launched from French Guiana in October 2018 atop an Ariane 5 rocket. The journey to Mercury is lengthy, roughly seven years, due to the Sun’s strong gravitational pull, which makes the transfer to the innermost planet challenging.

Engineering challenges and mission updates

A key part of the narrative is the mission’s propulsion system. The MMO and MPO are supported by four solar electric ion thrusters that effectively slow the spacecraft to enable capture by Mercury’s gravity. In April 2024 engineers discovered the thrusters were not operating at full power, meaning the mission would require additional time to reach Mercury. As a result arrival is now planned for November 2026, instead of December 2025. The video uses this moment to illustrate how space missions must adapt to in-flight anomalies and still achieve their scientific objectives.

Science goals and gallery models

Upon arrival, the plan is for the three vehicles to separate and continue into separate orbits. The MMO will focus on Mercury’s magnetosphere and solar wind interactions, while the MPO will investigate the interior structure and composition. The video underscores Mercury’s unique environment, including its interaction with the solar wind and its magnetic field, and why these studies help scientists understand Earth’s own magnetosphere and space weather.

Testing, readiness, and inspiration

The segment also features the Bepe Colombo structural thermal model in the Science Museum’s new space gallery. This model demonstrates how engineers test launch vibrations and extreme temperatures to ensure the flight model can endure space conditions. The discussion highlights lessons from past failures, such as insulation design across multiple layers, and how those lessons improve mission resilience and safety. The video ends with a call to like and subscribe for more space exploration stories.