The Planet Mercury:
BepiColombo To Explore Mercury
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The European Space Agency (ESA) and the Japan Space Exploration Agency (JAXA) Institute of Space and Astronautical Science (ISAS) are cooperating to send a pair of probes called BepiColombo to explore Mercury, the planet closest to the Sun.
European engineers say the mission will be one of the most challenging long-term planetary projects because Mercury orbits very close to the Sun. That makes it difficult for a spacecraft to travel there. Mercury also is difficult to observe from a distance.
Flying from Earth. BepiColombo would be launched in 2011-12 just as the work of the earlier probe, MESSENGER, work would be winding down at Mercury.
BepiColombo's trip would be a 3.5 year tour of the inner Solar System ending up in orbit around Mercury about 2015.
Two spacecraft. The BepiColombo project will include two spacecraft to map the planet and examine the planet's magnetosphere – Mercury Planetary Orbiter (MPO) and Mercury Magnetospheric Orbiter (MMO).
The orbiters. The MPO and MMO spacecraft will fly into orbit around the planet. They will have to withstand temperatures at Mercury above 500°F to send back pictures and data about the least explored planet in the inner Solar System. ESA's previous interplanetary spacecraft have traveled to colder parts of the Solar System.
- ESA is building MPO to study the surface and internal composition of the planet.
- ISAS is building MMO to study Mercury's magnetosphere, a region of space around the planet dominated by Mercury's magnetic field.
The lander. A small lander, called the Mercury Surface Element (MSE), also may be part of the package. It would measure the chemical composition and physical properties of the planet's surface, in particular how much iron is present in the top layer of crust. As the planet is surprisingly dense, the suspicion is that it has an unusually large iron core.
Whopper of a mission. BepiColombo, flying two or three spacecraft, will be a large, complex, costly mission. Each spacecraft would fly into a polar orbit around Mercury from where it would observe the planet for at least one Earth year. If one is sent, the lander would drop down to the surface within the first week after arriving at Mercury.
Launch choices. The two orbiters alone could be launched on a Soyuz-Fregat rocket from Russia's Baikonur Cosmodrome in Kazakhstan. The two orbiters and the lander would be launched on one of ESA's Ariane 5 rockets from Kourou, French Guiana. Either way, the spacecraft would take 3.5 years to travel to Mercury.
Innovative braking. Flying toward Mercury from Earth, the multiple spacecraft would have to be able to brake against the Sun's gravity. To slow down, they would use a new state-of-the-art solar electric propulsion (SEP) engine as well as the gravity of Earth's Moon, the planet Venus and Mercury.
What's in a name? BepiColombo is named after the late mathematician and engineer, Professor Giuseppe "Bepi" Colombo (1920-1984), from the University of Padua, Italy. Colombo had 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 1974-1975. He also had been the first person to understand that resonance is responsible for Mercury's process of rotating on its axis three times for every two revolutions it makes around the Sun.
Mariner 10. The only probe to have visited Mercury before this century was NASA's Mariner 10 which flew past the hot planet three times in 1974-1975. Previosuly, the only close-up pictures of the planet have been those sent home by Mariner 10.
ESA and JAXA scientists hope their BepiColombo will find valuable clues at Mercury to help us understand how planets of our Solar System formed.
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