ESA's first mission to Planet Mercury. BepiColombo
is a Mercury exploration project jointly planned by Japan and
the European Space Agency (ESA). BepiColombo is ESA's first
mission conducted in co-operation with Japan.
The mission was inspired by the late Italian
astrophysicist Dr. Giuseppe "Bepi" Colombo, who suggested that a
spacecraft could get close to Mercury several times by using a
gravity-assist swing-by of Venus. Hence the name of the project,
BepiColombo It is named BepiColombo in his honour.
BepiColombo will conduct
comprehensive observations of Mercury’s magnetic field,
magnetosphere, and both its surface and interior. That will help
determine how much it has in common with other planets and what
elements are unique to Mercury as well as the origin and
evolution of terrestrial planets.
Japan is planning a joint mission with the European Space Agency called
BepiColombo, which will orbit Mercury with two probes: one to map the planet and
the other to study its magnetosphere. An original plan to include a lander has
been shelved. Russian Soyuz rockets will launch the probes in 2013. As with
MESSENGER, the BepiColombo probes will make close approaches to other planets en
route to Mercury, passing the Moon and Venus and making several approaches to
Mercury before entering orbit. The probes will reach Mercury in about 2019,
orbiting and charting its surface and magnetosphere for a year.
Solar Orbiter are ESA's first long-range science missions designated to use an
- Origin and evolution of a planet close to the parent star
- Mercury as a planet: form, interior, structure, geology, composition and
- Mercury's vestigial atmosphere (exosphere): composition and dynamics
- Mercury's magnetized envelope (magnetosphere): structure and dynamics
- Origin of Mercury's magnetic field
- Test of Einstein's theory of general relativity
The BepiColombo mission is based on two spacecraft:
- a Mercury Planetary Orbiter (MPO); and
- a Mercury Magnetospheric Orbiter (MMO)
BepiColombo will make a complete map of Mercury
at different wavelengths. This will allow to map the planet's mineralogy and
elemental composition and determine whether the interior of the planet is molten
BepiColombo will set off in 2014 on a journey lasting approximately 6 years.
When it arrives at Mercury in August 2019, it will endure temperatures as high
as 350 °C and gather data during its 1 year nominal mission from September 2019
until September 2020, with a possible 1-year extension to September 2021.
The two components will be launched together on
a Soyuz 2-1B/Fregat-M booster
Apart from intensively studying the planet
itself, mission planners also hope to use the probe’s proximity to the Sun to
test the predictions of General Relativity theory with improved accuracy.
The mission is named after Giuseppe (Bepi) Colombo, the scientist who first
determined the nature of Mercury’s orbital resonance with the Sun and who was
also involved in the planning of Mariner 10’s gravity-assisted trajectory to the
planet in 1974.
The mission will consist of two separate spacecraft that will orbit the
planet. ESA is building one of the main spacecraft, the Mercury Planetary
Orbiter (MPO), and the Japanese space agency ISAS/JAXA will contribute the
other, the Mercury Magnetospheric Orbiter (MMO).
The MPO will study the surface and internal composition of the planet, and
the MMO will study Mercury's magnetosphere, that is the region of space around
the planet that is dominated by its magnetic field.
The mission presents
enormous, but exciting challenges. All of ESA's previous inter-planetary
missions have been to relatively cold parts of the Solar System. BepiColombo
will be the Agency's first experience of sending spacecraft to 'hot' regions.
The journey from Earth to Mercury will also be
a first. On its way to
Mercury, the spacecraft must brake against the Sun's gravity, which increases
with proximity to the Sun, rather than accelerate away from it, as is the case
with journeys to the outer Solar System. BepiColombo will accomplish this by
making clever use of the gravity of the Earth, Venus and Mercury itself and by
using solar electric propulsion (SEP). This innovative combination of low thrust
space propulsion and gravity assist has been demonstrated by ESA's technology
When approaching Mercury, the spacecraft will use the planet's gravity plus
conventional rocket engines to insert itself into a polar orbit.
||Spin axis at 90° to Sun
||400 × 1508 km
||400 × 11 824 km
||> 1 year
||> 1 year
|Equivalent average data rate
||High-temperature resistant 1.0 m X/Ka-band high-gain steerable antenna
||0.8 m X-band phased array high-gain antenna
||high temperature resistant thermal
protection, solar arrays
cameras, spectrometers (IR, UV, X-ray,
γ-ray, neutron), radiometer, laser altimeter, magnetometer, particle
analyser, Ka-band transponder, accelerometer
||magnetometer, ion spectrometer, electron
energy analyser, cold and energetic plasma detectors, plasma wave analyser,
The mission operation centre will be located at the European Space Operations
Centre (ESOC) in Darmstadt, Germany. The ground telemetry station for the MPO
and MMO spacecraft will be the Cebreros (Spain) 35m antenna (8 hours/day) and
the Usuda (Japan) 64m antenna (6-8 hours/day) respectively.
A European mission to Mercury was first proposed in May 1993. Although an
assessment showed it to be too costly for a medium-size mission, ESA made a
Mercury orbiter one of the three new Cornerstones missions when the Horizon 2000
science programme was extended in 1994.
Gaia competed with BepiColombo for the fifth Cornerstone mission. In October
2000, ESA approved a package of missions for 2008–2013 and both BepiColombo and
Gaia were approved.
Spacecraft and Subsystems
The MPO and MMO spacecraft will each be driven by a Solar-Electric Propulsion
Module (SEPM) and a chemical propulsion module (CPM). The SEPM is optimal for
slow cruise manuevers and will consist of a set of xenon ion thrusters housed in
a rectangular prism powered by two GaAs-cell solar panel wings covering 33
square meters. The panels will be progressively tilted away from the Sun as the
spacecraft gets closer from 0.6 AU to 0.32 AU in order to provide approximately
constant power, about twice the 5.5 kW available at 1 AU. Three thrusters will
be available, one or two to be used at any given time. The nominal thrust is
planned to be 0.17 or 0.34 N. The total dry mass of the unit is 365 kg with 230
kg of xenon fuel for the MPO and 238 kg for the MMO. The CPM is a bi-propellant,
N2O4-MMH, system for attitude control and orbital insertion. Attitude control
will be achieved by eight 20_N thrusters, other maneuvers will be achieved with
a single 4000 N engine. The dry mass of the CPM is 71 kg, with 156 kg of fuel
for MPO and 334 kg for MMO. The total launch mass of the entire MPO system will
be 1229 kg and for MMO about 1200 kg.
Mercury Planetary Orbiter (MPO)
The Mercury Planetary Orbiter will be a 357 kg spacecraft in the shape of a
flat prism with three short sides slanted at 20 degrees covered with solar cells
providing 420 W at perihelion. A radiator with an area of 1.5 square meters is
mounted on one side to provide thermal control. The radiator is always pointed
away from the Sun and is protected from planetary IR with a 3.4 square meter
shield. High efficiency insulation is also used. A 1.5 m diameter high gain
antenna is mounted on a short boom on the zenith side of the spacecraft. The MPO
will be 3-axis stabilized and nadir pointing with a planned lifetime of over 1
year in Mercury orbit. Communications will be on the X/Ka band with an average
bit rate of 50 kb/s and a total data volume of 1550 Gb/year. A UHF dipole
antenna mounted on the nadir side will be used for possible communications with
the MSE. Navigation knowledge is provided by 3 star sensors.
The MPO will carry an imaging system consisting of a wide-angle and narrow
angle camera, an infrared spectrometer, an ultraviolet spectrometer, gamm,
X-ray, and neutron spectrometers, a laser altimeter, a Near Earth Object
telescope and detection system, and radio science experiments.
Mercury Magnetospheric Orbiter (MMO)
The Mercury Magnetospheric Orbiter has the shape of a flat cylinder with a
mass of 165 kg. The MMO is spin stabilized at 15 rpm with the spin axis
perpendicular to the equator of Mercury. The top and bottom of the cylinder act
as radiators with louvers for active temperature control. The side is covered
with solar cells which provide 185 W and second surface mirrors and protected by
thermal blankets. Communications with Earth are amintained through a despun
1-meter diameter high-gain offset antenna and two medium-gain antennas operating
in the X-band. Telemetry will return 160 Gb of data per year at about 5 kb/s
over the lifetime of the craft, which is expected to be greater than one year. A
microstrip UHF patch antenna will be used for communication with the MSE. The
reaction and control system is based on cold gas thrusters. Deployable booms and
wire antennas are stowed until orbit is achieved. The MMO will carry a set of
fluxgate magnetometers, charged particle detectors, a wave receiver, a positive
ion emitter, and an imaging system.
Mercury Surface Element (MSE)
The Mercury Surface Element has been cancelled due to budgetary constraints.
The description which follows gives the general plan for the MSE at the time of
cancellation. MSE is a small (44 kg) lander designed to operate for about one
week on the surface of Mercury. The MSE is a 0.9 m diameter disc which is
designed to land at a latitude of 85 degrees near the terminator region.
Following the release of the MMO, a burn of the 4 kN thruster will put the MSE
into a 10 km orbit. Another braking maneuver controlled by gyros/accelerometers
and an optical range/range-rate sensor will bring the MSE to zero velocity at an
altitude of 120 meters at which point the propulsion unit will be ejected, the
airbags inflated, and the module will fall to the surface with a maximum impact
velocity of 30 m/s. If the landing occurs in sunlight a thermal protection cover
will Since 40% of the terrain at the landing point will be in shadow, primary
power is supplied by a 1.7 kWh battery. Scientific data will be stored onboard
and relayed via a cross-dipole UHF antenna to either the MPO or MMO at a data
rate of 8.7 kb/s providing for a total of 75 Mb over 7 days, assuming 18 contact
periods of 480 seconds each. The MSE will carry a 7 kg payload consisting of an
imaging system (a descent camera and a surface camera), a heat flow and physical
properties package, an alpha X-ray spectrometer, a magnetometer, a seismometer,
a soil penetrating device (mole), and a micro-rover.
BepiColombo is named for Giusseppe (Bepi) Colombo (1920-1984), scientist,
mathematician and engineer at the University of Padua, Italy. The total
estimated cost of the mission is 650 million euros.
BepiColombo is named after Professor Giuseppe (Bepi) Colombo (1920-1984) from
the University of Padua, Italy, a mathematician and engineer of astonishing
imagination. He was the first to see that an unsuspected resonance is
responsible for Mercury's habit of rotating on its axis three times for every
two revolutions it makes around the Sun. He also suggested to NASA how to use a
gravity-assist swing-by of Venus to place the Mariner 10 spacecraft in a solar
orbit that would allow it to fly by Mercury three times in 1974-5.
ESA's Science Programme Committee decided at its meeting in Naples in 1999 to
name the Mercury cornerstone in honour of Giuseppe Colombo's achievements.
Observation mission by BepiColombo
This project consists of two orbiters. Mercury
Planetary Orbiter (MPO) will observe the surface and interior; Mercury
Magnetospheric Orbiter (MMO) will observe the magnetic field and the
magnetosphere. JAXA is responsible for MMO, as Japan excels in the study of
magnetic fields and magnetospheres. ESA is responsible for the launcher, the
interplanetary cruising engine, the placement of BepiColombo into Mercury’s
orbit, and the development of MPO.
Other Planet Mercury Spacecraft:
Mariner 10, Messenger.
Name BepiColombo is named after Giuseppe (Bepi) Colombo
(1920-1984), a scientist who studied Mercury's orbital motion in
detail as well as orbits and interplanetary travel in general.
orbiters will be launched together on a single Ariane 5 rocket
from ESA's Spaceport in Kourou, French Guiana. To guide its
journey, BepiColombo will exploit the gravity of the Earth,
Venus and Mercury in combination with solar-electric propulsion
During the voyage to Mercury the two orbiters and the transfer
module, consisting of electric propulsion and traditional
chemical rocket units, will form one single composite
spacecraft. Arrival at Mercury will be in 2020..
The journey from Earth to Mercury is also special because the
spacecraft must brake against the Sun's gravity, which increases
with proximity to the Sun. This requires a lot of energy. Most
other missions must accelerate away from the Sun, as it is the
case with journeys to the outer Solar System.
Programme: To Ariane and Beyond
by Brian Harvey
* Most of ESA's previous interplanetary missions have been to
relatively cold parts of the Solar System. BepiColombo will be
the Agency's first experience of sending a planetary probe close
to the Sun.
* Professor Colombo is best known
for the discovery of the spin-orbital coupling of Mercury and
the planning of multiple fly-by of Mercury in 1972-1973. He
promoted the conceptual design of the Solar Probe mission, the
Skyhook concept applications, a new type of orbiting gravity
gradiometer and gave the interpretation of the azimuthal
brightness variation of ring A of Saturn as a spiral structure.
He studied new concepts concerning space transportation, large
space structures and evolution of space technology for space
sciences and applications.
* The proximity of Mercury to the Sun makes it difficult to
observe and hard to reach by space flight.
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