| | BepiColombo
| ROLE | Mercury observation and exploration |
| LAUNCH DATE | Jul-Aug 2014 |
| LAUNCHER | Ariane 5 |
| LAUNCH MASS | 4200 kg |
| ORBIT | MPO: polar orbit, 400×1500 km, 2.3hr period
MMO: polar orbit, 400×12 000 km, 9.2hr period |
NOMINAL
MISSION | Arrival: November 2020 - nominal 1 year in Mercury orbit |
| + ESA's first mission to Mercury will provide clues on how planets form and interact with the Sun + |
 | | | Artist's impression of the Mercury Composite Spacecraft during the interplanetary cruise to Mercury. |
The mission
BepiColombo - ESA's first mission to Mercury - will be conducted in cooperation with Japan. The mission will consist of two separate spacecraft: ESA is building the Mercury Planetary Orbiter (MPO), and the Japanese space agency JAXA will contribute the Mercury Magnetospheric Orbiter (MMO).
Europe's space scientists have identified the mission as one of the most challenging long-term planetary projects, as Mercury's proximity to the Sun makes it difficult for a spacecraft to reach and survive in the harsh environment. Scientists are keen to go to Mercury for the valuable clues that such a mission can provide in understanding the planet itself as well as the formation of our solar system; clues which cannot be obtained with distant observations from Earth.
The objectives of the mission are:
- Study the origin and evolution of a planet close to its parent star
- Study Mercury as a planet - its form, interior, structure, geology, composition and craters
- Investigate Mercury's vestigial atmosphere (exosphere) - its composition and dynamics
- Study Mercury's magnetised envelope (magnetosphere) - structure and dynamics
- Investigate the origin of Mercury's magnetic field
- Confirm Einstein's theory of general relativity
MPO will study the surface and internal composition of the planet, while MMO will study Mercury's magnetosphere, the region of space around the planet that is dominated by its magnetic field.
Astrium GmbH has been selected as Prime Contractor to build the European part of the space segment.
| | | Elsa Montagnon |
The Flight Control Team The MPO Flight Control Team (FCT) will operate the Mercury Planetary Orbiter from a Dedicated Control Room located at ESOC, in Germany. Elsa Montagnon was appointed as Spacecraft Operations Manager (SOM) in December 2006. Under her lead, the team is now working on mission operations definition and ground segment specification.
The FCT will be supported in-flight by specialists from Flight Dynamics, Ground Facilities, and Mission Data Systems.
Mission operations overview
BepiColombo, one of the 'cornerstones' in ESA's long-term science programme, presents enormous but exciting challenges. Apart from Venus Express, all 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 spacecraft so close to the Sun.
| | | Artist’s view of BepiColombo at Mercury |
The journey from Earth to Mercury will also be a first for the Agency.
The Mercury Composite Spacecraft - consisting of the MPO and MMO spacecrafts, a Transfer Module (MTM) and a Sun-shield for the MMO (MOSIF)– will be launched into an interplanetary trajectory in July 2014.
On its long 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 in 2015, Venus (twice in 2016) and Mercury itself (in 2017, 2018 and twice in 2019) and by using solar electric propulsion (SEP).
This innovative combination of low-thrust space propulsion and gravity assist was earlier demonstrated by ESA's technology mission to the Moon, SMART-1.
| | | BepiColombo orbits |
When approaching Mercury, the MTM will be jettisoned and the remaining composite spacecraft will then use a special 'Weak Stability Boundary Capture' technique to insert itself into a polar orbit, which will be stabilised by means of conventional chemical propulsion engines. The arrival will take place in November 2020.
Orbit insertion using the ‘Weak Stability Boundary’ method gives flexibility and is more robust against failure compared to using the more traditional "big kick" approach (using a single burn of the main engine to achieve capture).
MMO will be released into its operational orbit, then the sun-shield and the MMO interface structure will be separated while the chemical propulsion system will bring MPO to its lower orbit.
The mission design and deployment sequence is depicted in the animation on this page. The prime scientific mission in orbit is planned to start in February 2021, lasting one Earth year, with a possible extension of one year.
The ground station
Cebreros - DSA 2
The primary ground station for BepiColombo will be ESA's 35m deep space station at Cebreros, Spain, for 8 hours/day. This will be augmented by the 35m station at New Norcia, Australia, and the Malargüe, Argentina, 35m deep space antenna during critical phases. A cross-support agreement with JAXA ensures that the Japanese Usuda Deep Space Centre's 64m antenna can be also be used as back-up during critical phases and in case of problems.
| | | ESA's deep space antenna DSA 2 at Cebreros, Spain. |
During the cruise to Mercury, the Mercury Composite Spacecraft will be controlled by ESOC.
After arrival at Mercury and separation of the MMO by spin-ejection, JAXA's Sagamihara Space Operation Centre, located south-west of Tokyo, will take over control of MMO via the Usuda Deep Space Centre’s 64m antenna, located in Nagano, Japan. ESOC will retain control of the MPO until the end of the mission.
The platform and payload
Visible from the bottom are: the BepiColombo transfer module, the Mercury Planetary Orbit (MPO), the sun shield and the Mercury Magnetospheric Orbiter (MMO)
The platforms
| Mercury
Planetary
Orbiter (MPO) | Mercury
Magnetospheric
Orbiter (MMO) | | Stabilisation | 3-axis stabilised | 15-rpm spin-stabilised | | Orientation | Nadir | Spin axis at 90° to Sun | | Spacecraft Mass | 1100 kg | 250 kg | | Payload Mass | 80 kg | 40 kg | | Power | 834 W | 300 W | | TM band | X/Ka-band | X-band | | Deployment | 400 × 1508 km | 400 × 11 824 km | | Operational lifetime | > 1 year | > 1 year | | Data volume | 1550 Gb/year | 160 Gb/year | | Equivalent average data rate | 50 kb/s | 5 kb/s | | Antenna | High-temperature resistant 1.0 m X/Ka-band high-gain steerable antenna | 0.8 m X-band phased array high-gain antenna | | Thrusters | Ion thrusters | | Other equipment | high temperature resistant thermal protection, solar arrays |
The payloads
| Planetary orbiter | cameras, spectrometers (IR, UV, X-ray, γ-ray, neutron), radiometer, laser altimeter, magnetometer, particle analyser, Ka-band transponder, accelerometer | | Magnetospheric orbiter | magnetometer, ion spectrometer, electron energy analyser, cold and energetic plasma detectors, plasma wave analyser, and imager |
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