What’s Going to Mercury?

Not only is this Saturday the International Observe the Moon Night but ESA’s BepiColombo is set to launch as well at 1:45 (UTC) on Saturday. That’s about 2:45pm in New Zealand so we’ll all be glued to the live feed  watching the lift off of the Ariane 5 from Launch Area 3 in Kourou, French Guinea. ESA has been putting the system through their final rehearsals today so that everything is ready for Saturday. Getting ready for a mission like this is no easy task with four months of simulations where the teams practiced every phase so they know what to be ready for and able to deal with any surprises. Launching a spacecraft puts the vehicle under an enormous amount of stress including high acceleration forces and quite a bit of shaking so it’s a critical and stressful time when it comes to switching the spacecraft systems on after launch to ensure everything is working fine.

The components of BepiColombo (Credit: ESA)

The flight profile for the mission has BepiColombo separating from the rocket’s upper stage about 26 minutes into the flight before it begins it’s 9 billion km journey over 7 years and conducting 9 planetary flybys. All of this is to reach one of the most least explored planets of the Solar System, Mercury. It won’t get there until 2025 so there’s plenty of time to get ready for the amazing images that will start flowing back.

The mission is actually two spacecraft in one as once the BepiColombo gets to Mercury it will separate into the two spacecraft that will conduct different missions. One orbiter is the Mercury Planetary Orbiter (MPO) and it’s packed full of instruments to study the surface and the inside of the planet. MPO has cameras, spectrometers, a radiometer, a laser altimeter, a magnetometer, a particle analyser, a Ka-band transponder, and an accelerometer. MPO is the bigger of the two spacecraft, weighing in at 1150kg.

The other mission is the Mercury Magnetospheric Orbiter (MMO) which is a JAXA led mission. MMO’s job is to get a better understanding of Mercury’s magnetosphere. Onboard MMO are a magnetometer, an ion spectrometer, an electron energy analyser, plasma detectors, a plasma wave analyser, and an imager. MMO is the smaller of the two weighing just 275kg. When both spacecraft get to Mercury MMO will be controlled by JAXA and MPO will remain under the control of ESA.

MMO and MPO (Credit: ESA)

This week is a great time to see Mercury as it’s slightly above Venus in the early evening sky. You’ll need a good horizon though as Mercury is quite close to the sun and can be tricky to see. Mercury is quite small at only about 38% of the Earth’s diameter and it has almost the same gravity as Mars. Humans haven’t sent many probes to Mercury with Just mariner 10 and Messenger being the only two. Messenger sent back many highly detailed images of the planet’s surface, which resembles the Moon in many ways. Messenger was crashed into the planet’s surface on 30 April 2015. Maybe MPO will photograph the crash site when it gets there in 2025. Lets hope that everything goes well on Saturday and BepiColombo safely gets on its way to Mercury.