The ESA probe BepiColombo flew past Earth on the way to Mercury. The probe launched in 2018 and made the last visit of our home before continuing onward to the final destination. The spacecraft needs to shed velocity to arrive at Mercury in 2025 at a velocity to enter orbit. The spacecraft will make multiple additional planetary flybys of Venus and Mercury to slow down to enter orbit.
In space travel, mission planners need to balance mission resources. The amount of fuel required to either speed up or slow down a spacecraft greatly impacts the cost of the mission. Using a longer flight path can reduce the propellent requirements for a mission but the mission will take longer. Gravity assists can, therefore, allow a spacecraft to be launched on a cheaper, less powerful rocket.
Gravity assist flyby?
A Gravity assist flyby has other names including a gravitational slingshot, gravity assist maneuver, or swing-by. Gravity assistance maneuvers increase or decrease its speed or redirect the orbital path. The spacecraft slingshots around another object with a gravitational field and transfers some of the energy during that slingshot. In the case of BepiColombo, the spacecraft needs to slow down to be captured by Mercury. (Click here to see where the spacecraft is now)
Bepi skimmed past Earth within 13,000km (8,000 miles). After the flyby of Earth, Bepi must perform similar maneuvers at Venus twice and Mercury six times. Gravity Assists are common in modern spaceflight. In 1959 the Soviet probe Luna 3 became the first spacecraft to employ the gravity assist maneuver. The historic interplanetary probes Voyager 1 & 2 both included flybys of Jupiter and Saturn.
In addition to the delta-V, the orbital inclination needs adjustment. The orbit of Mercury’s orbit and Earth’s orbit requires a 6 degrees change. Even with the swing-bys, the Mercury Transfer Module (MTM) will be utilized from course adjustments and some of the delta-V.
More about BepiColombo spacecraft.
BepiColombo’s mission includes two satellites. The satellites include one from the European Space Agency (ESA) and one from the Japan Aerospace Exploration Agency (JAXA). ESA provided the Mercury Planetary Orbiter (MPO). JAXA provided the Mercury Magnetospheric Orbiter (MMO) BepiColombo marks the first joint mission between ESA and JAXA to the planet Mercury.
BepiColombo launched on 20 October 2018. The mission leverages multiple gravity assists. BepiColombo mission name selection honors Giuseppe “Bepi” Colombo(1920–1984), who proposed using gravity assist maneuvers for planetary spacecraft.
During the Earth flyby, mission controllers turned on a number of instruments for calibration. Don’t expect any great photographs of Earth from the flyby. The main camera on Europe’s MPO orientation in the spacecraft nestled inside doesn’t allow for any pictures. Small inspection cameras to the side of the probe offered some black & white pictures of the Earth and Moon.
What science will BepiColombo do at Mercury?
When it arrives at Mercury in late 2025, the satellites will be exposed to temperatures in excess of 350 °C. The data collection phase of the mission may be extended from one year to two years.
MPO will map Mercury’s terrain. In parallel, the probe will collect information about the planet’s surface structure, composition and peer into the planet’s interior.
The MMO will study Mercury’s magnetic field. It will also study the magnetic field’s behavior and interaction with the solar wind. The solar wind bombards Mercury with highly active particles Mercury. Earth’s Magnetic field helps protect the atmosphere and life by shielding the planet from the harmful radiation of the sun.
MESSENGER spacecraft. Credits: NASA
Mission objectives from the ESA website.
- The scientific objectives behind BepiColombo can be viewed by considering the following 12 questions: What can we learn from Mercury about the composition of the solar nebula and the formation of the planetary system?
- Why is Mercury’s normalized density markedly higher than that of all other terrestrial planets, Moon included?
- Is the core of Mercury liquid or solid?
- Is Mercury tectonically active today?
- Why does such a small planet possess an intrinsic magnetic field, while Venus, Mars and the Moon do not have any?
- Why do spectroscopic observations not reveal the presence of any iron, while this element is supposedly the major constituent of Mercury?
- Do the permanently shadowed craters of the polar regions contain sulfur or water ice?
- Is the unseen hemisphere of Mercury markedly different from that captured by Mariner 10?
- What are the production mechanisms of the exosphere?
- In the absence of any ionosphere, how does the magnetic field interact with the solar wind?
- Is Mercury’s magnetized environment characterized by features reminiscent of the aurorae, radiation belts and magnetospheric substorms observed at Earth?
- Since the advance of Mercury’s perihelion was explai
About The Author
Bill D’Zio
Co-Founder at WestEastSpace.com
Bill founded WestEastSpace.com after returning to China in 2019 to be supportive of his wife’s career. Moving to China meant leaving the US rocket/launch industry behind, as the USA and China don’t see eye to eye on cooperation in space. Bill has an engineering degree and is an experienced leader of international cross-functional teams with experience in evaluating, optimizing and awarding sub-contracts for complex systems. Bill has worked with ASME Components, Instrumentation and Controls (I&C) for use in launch vehicles, satellites, aerospace nuclear, and industrial applications.
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