Mercury is the least explored planet in our inner solar system. In late October this year, a new mission was launched with the goal of learning more about the Sun’s nearest neighbour.
On 20 October a rocket carrying two scientific spacecraft called ‘probes’ left Earth and began its seven-year-long journey towards Mercury.
The BepiColombo mission – named after an Italian scientist who pioneered a technique commonly used by orbital probes – is a joint venture by the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA).
This is only the third mission to Mercury and it is the most ambitious, being the second to enter the planet’s orbit. From 2011 to 2015 NASA’s MESSENGER probe was the first to study the planet from orbit.
In comparison the BepiColombo mission consists of two probes: the Mercury Planetary Orbiter (MPO) built by the ESA, and the Mercury Magnetospheric Orbiter or Mio built by JAXA.
Upon reaching orbit, the probes will separate from the propulsion system – the Mercury Transfer Module – and are scheduled to stay in orbit for a minimum of two years with the possibility of an extension.
Mercury Magnetospheric Orbiter
The two probes are specialised to gather scientific data in separate fields of research. The Mio will observe Mercury’s magnetosphere, specifically how it interacts with the Sun’s solar winds.
Mio will rotate continuously, partly to dissipate the scorching 400-degree Celsius heat from the Sun, but also to get a full view of how particles flow through the planet’s magnetic field.
‘Our particle sensors can cover almost [the entire] field of view,’ says Go Murakami, a planetary scientist at JAXA’s Institute of Space and Astronautical Science.
According to Murakami, by studying how the solar winds pass around Mercury, we could learn more about conditions on similar planets in the universe, including whether or not they could be conducive to life.
Mercury Planetary Orbiter
The Mio’s counterpart, the MPO, will mostly focus on scanning and mapping the surface of Mercury.
The European probe’s wide array of instruments will allow it to analyse the electromagnetic spectrum of the planet which could help us understand Mercury’s chemical composition.
The MPO will also take readings of Mercury’s gravitational field and consequently its unique iron core. Mercury’s molten iron core makes up about 85% of the planet’s radius and despite being the smallest planet in our solar system it contains the most iron.
Nancy Chabot, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory says, ‘The thing that’s really exciting about MPO is [its] low-orbit altitude.’ This will enable high resolution mapping of Mercury’s surface.
Future Missions to Mercury
Chabot is one of the top scientists on NASA’s MESSENGER mission and is still processing the data collected by the probe.
Despite Mercury’s proximity to the Sun, she says there is some evidence of ice deposits in the shadowy areas of craters near the planet’s north pole. Some may also exist near the south pole
She advocates further study of these potential ice-containing craters and says that the next mission to Mercury should aim to land on the planet. ‘Getting down to the surface is the next step,’ says Chabot.
No matter what the future holds for further exploration of Mercury it is certainly exciting to know that the next phase is already underway.
By studying the Earth’s siblings, we could potentially uncover more secrets about the vast universe we live in and our place in it.