Leicester University's MIXS on integrated BepiColombo science orbiters
The two science orbiters of the joint ESA-JAXA BepiColombo mission carrying the Mercury Imaging X-ray Spectrometer (MIXS) developed by the University of Leicester, are now connected in their launch configuration and the European science orbiter and transport module have been given the go-ahead to be loaded with propellants.
Above:
ESA’s Mercury Planetary Orbiter (MPO, bottom) and JAXA’s Mercury Magnetospheric Orbiter (MMO, top) arranged in their launch configuration at Europe’s Spaceport in Kourou, in preparation for a 'fit check' with the Mercury Transfer Module (not visible in this image).
Copyright ESA / B.Guillaume
The mission completed its Qualification Acceptance Review in the last week, which confirms it is on track for its 19 October launch. The three-spacecraft mission is currently scheduled to launch on an Ariane 5 at 03:45 CEST (01:45 GMT) on 19 October, or 22:45 local time in Kourou on 18 October, with the launch window remaining open until 29 November.
Following the successful fuelling readiness review on 30 August, the chemical propellants – such as hydrazine – can be added to the European Mercury Transfer Module (MTM) and Mercury Planetary Orbiter (MPO).
“These important reviews represent further key milestone in our launch campaign, bringing us to the final stages of our launch preparations, while in the longer term enabling the journey and operations at Mercury,” says Ulrich Reininghaus, ESA’s BepiColombo project manager.
“With the fueling activities planned for 5–12 September, a technical point of no return will be reached. After mechanical stacking, final electrical health check and transfer to the final assembly building, the launch will be the next major event.”
The transfer module will use both ion propulsion and chemical propulsion, in combination with gravity assist flybys at Earth, Venus and Mercury to bring the two science orbiters close enough to Mercury to be gravitationally captured into its orbit. There, MPO will use its small thrusters to deliver JAXA’s Mercury Magnetospheric Orbiter (MMO) into its elliptical orbit around Mercury, before separating and descending to its own orbit closer to the planet.
This month the two science modules were arranged in their launch configuration for the first time in over a year; the last occasion was at ESA’s technical centre in the Netherlands during final testing before shipment to Europe’s Spaceport in Kourou, French Guiana.
The MTM will be integrated at the bottom of the stack once the propellant-loading activities have been completed. A test-run of the integration was already exercised last week with the unfueled modules. The sunshield that will protect the MMO from the Sun’s radiation on the seven year journey will also be added much closer to launch.
BepiColombo carries the Mercury Imaging X-ray Spectrometer (MIXS), developed by the University of Leicester, as part of its scientific payload. By measuring fluorescent X-rays from the surface, MIXS will provide a detailed analysis of the surface elemental composition of Mercury to aid our understanding of the planet’s evolution and formation processes. The MIXS data set will also provide information on surface-exosphere-magnetosphere interactions.
Professor Emma Bunce, Principal Investigator at the University of Leicester, said: “It is fantastic news to hear that the ESA/JAXA BepiColombo has reached this important “fuelling readiness” milestone out at the launch site in Kourou. Once topped up with fuel there is no going back, and the next stop is the launch itself. We are very excited here at the University of Leicester that the BepiColombo mission will finally be on its way to Mercury after years of hard work.
“We still will have to wait for another 7.2 years until our instrument begins its scientific mission – but with the exciting discoveries waiting to be made it will be well worth the wait!”
“The long journey to Mercury has not yet started, but I feel the two science orbiters already have a strong bond between them, thanks to the long history of this mission,” says Go Murakami, JAXA’s BepiColombo project scientist. “I believe they will achieve a very successful mission with their joint science measurements.”
MMO’s main science goals are to provide a detailed study of the magnetic environment of Mercury, the interaction of the solar wind with the planet, and the diverse chemical species present in the exosphere – the planet’s extremely tenuous ‘atmosphere’.
The MPO will focus more on surface processes and composition, and together with MMO, will help piece together the full picture of the interaction of the solar wind on the planet’s environment and surface. Together they will watch how this interaction at the surface feeds back into what is observed in the exosphere and how that varies both in time and location – something that can only be achieved with two spacecraft in such complementary orbits.
“Seeing the two BepiColombo science orbiters finally attached together and knowing that they will now stay in this configuration for the next seven years is quite emotional,” said Johannes Benkhoff, ESA’s BepiColombo project scientist. “It’s another strong indication that we will start our mission soon and I’m really looking forward to all the science measurements we have planned with instruments on these two orbiters.”