Of all the planets of the inner Solar System, Mercury is the least-visited. No mission has ever landed on its surface, only two missions have studied it from space, and only one of those has reached orbit.
Travelling to Mercury is difficult as the proximity to the Sun makes for unstable orbits and fast orbital speeds.
The first spacecraft to visit Mercury was Mariner 10, pictured here in an artist’s impression from UCL’s planetary science archives. UCL is the only UK institution to host a NASA Regional Planetary Image Facility.
Mariner 10 made three fly-bys of Mercury in 1974 and 1975, mapping a little under half of the planet’s surface.
The complex path to Mercury, involving multiple fly-bys, was designed by scientist Bepi Colombo, whose name is honoured by a forthcoming mission planned by the European Space Agency and the Japan Aerospace Exploration Agency. The BepiColombo mission, expected to launch in 2016, will feature two orbiters, and will fly past the planet several times before reaching orbit in 2024.
UCL’s Prof Alan Smith is chair of the UK Space Agency’s BepiColombo management board.
Image credit: NASA/RPIF/UCL Earth Sciences
- Snapshots from Space History (UCL RPIF public outreach website)
- UCL Regional Planetary Image Facility
- UCL Earth Sciences
- UCL Mullard Space Science Laboratory