BepiColombo
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This article or section contains information regarding a future spaceflight. Due to the nature of the content, details may change dramatically as the launch date approaches and/or more information becomes available. |
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| BepiColombo | |
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 Computer rendition of what the two BepiColumbo orbiters might look like |
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| Organization: | European Space Agency, Japan Aerospace Exploration Agency |
| Mission type: | Orbiter |
| Flyby of: | Moon,Venus, and Mercury |
| Satellite of: | Mercury |
| Orbital Insertion date: | August, 2019 |
| Launch Date: | August, 2013 |
| NSSDC ID: | BEPICLMBO |
| Webpage: | http://sci.esa.int/science-e/www/area/index.cfm?fareaid=30 |
| Mass: | 357 kg (MPO) |
| Power: | 5.5 kW available at 1 AU |
| Orbital Period: | 2.3 hr (MPO) |
| Apoapsis: | 1500 km (MPO) |
| Periapsis: | 400 km (MPO) |
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BepiColombo is a joint Cornerstone mission of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) to the planet Mercury. The mission is still in the planning stages so changes to the current description are likely over the next few years. Due to budgetary constraints and technological difficulties the lander portion of the mission (The Mercury Surface Element, or MSE) was cancelled.
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[edit] Mission
The mission as currently envisioned involves two components: the Mercury Planetary Orbiter (MPO) build by ESA and the Mercury Magnetospheric Orbiter (MMO) build by JAXA. The two components are planned to be launched together on a Soyuz-Fregat launch vehicle in August 2013. The spacecraft will have a six year interplanetary cruise to Mercury using solar-electric propulsion and gravity assists from the Moon, Earth, Venus and Mercury.
Arriving in Mercury orbit in August 2019, the spacecraft will have a 1-year nominal scientific life. The MPO will be equipped with eleven scientific instruments provided by various European countries including visible imagers, a laser altimeter and an imaging X-ray spectrometer. Russia will provide a gamma ray and neutron spectrometer. It will attempt to map the entire surface, in several different wavelengths, and to find water ice in polar craters which are permanently in shadow from the sun's rays.
[edit] 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.
ESA has selected Astrium as the prime contractor for the construction of the MPO.[1]
[edit] Mercury Magnetospheric Orbiter (MMO)
The Mercury Magnetospheric Orbiter has the shape of a flat cylinder with a mass of 165 kg.[2] 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.
[edit] 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.
[edit] Propulsion
BepiColumbo will be propelled by a form of ion drive dubbed solar electric propulsion, which has a very high specific impulse and very low thrust. Unlike a chemical rocket which fires for a few seconds, it will keep propelling the craft for years, building up far more speed per mass of fuel in the long run. This will be the first mission to another planet (excluding the moon mission by SMART-1) using such a form of propulsion.
This drive will be tested by the unusual need to actually push against the direction of travel, instead of with it; the ship will be falling toward the sun, accelerated by its gravity, and will have to constantly fight to keep its velocity slow enough to eventually enter Mercury's orbit.
[edit] Namesake
BepiColombo is named for Giuseppe (Bepi) Colombo (1920-1984), scientist, mathematician and engineer at the University of Padua, Italy, who developed the gravity-assist maneuver commonly used by planetary probes today. He helped NASA devise the trajectory of Mariner 10, the only spacecraft having encountered Mercury till today, exploiting this maneuver for the first time around Venus.
[edit] See also
[edit] References
- ^ BepiColombo To Enter Implementation Phase. ESA.
- ^ H. Yamakawa, H. Ogawa, Y. Kasaba, H. Hayakawa, T. Mukai, M. Adachi (2004). "Current status of the BepiColombo/MMO spacecraft design". Advances in Space Research 33: 2133–2141. DOI:10.1016/S0273-1177(03)00437-X.
[edit] External links
| Mercury Spacecraft Missions | |
|---|---|
| Flybys: Mariner 10 | |
| Future: MESSENGER · BepiColombo | |
| See also: Mercury · Exploration of Mercury | |
