spaceSpace and Physics

Double Flyby For Venus As Two Probes To Vist Within Hours Of Each Other Next Week


Stephen Luntz

Freelance Writer

clockAug 6 2021, 14:50 UTC
venus missions

BepiColombo (artist's impression shown here) and Solar Orbitor will perform flybys of Venus just 33 hours apart next week. Image Credit: ESA/ATG Medialab

If Venus was a sentient being it would be feeling like someone catching public transport – you wait hours for a bus, and then along come two at once. In Venus's case, no probes have newly visited it since 2015, and it's about to get two in 33 hours.

Early on Monday, August 9, at 4:42 am UTC (12.42 am ET) the European Space Agency's Solar Orbiter will fly past Venus at a distance of 8,000 kilometers (5,000 miles). At 1:48 pm UTC (9:48 am ET) the next day BepiColombo, a joint venture of the ESA and Japanese Space Agency will make a considerably closer approach – just 550 kilometers (340 miles).


As its name suggests, this is just a casual visit for Solar Orbiter – its main task is to study the Sun and is just using Venus as a gravity assist so it can get closer to its goal without using too much fuel. It can't even turn its cameras on Venus as it passes, needing to stay orientated to the Sun. BepiColombo's goal is Mercury, to become the second craft to orbit after MESSENGER, and is also using Venus as a gravity assist to get closer towards its target. Its view will be partially blocked by its transfer module, but it should still manage to view Venus with two of its three cameras as it passes.

double venus flyby ESA
Two missions will make flybys past Venus in the space of 33 hours to help them travel further into the Solar System. Image Credit: European Space Agency

The two spacecraft will, however, be able to investigate the magnetic and plasma environment around Venus, and the coincidence of their timing may tell us something about changes occurring there, for example how changes in the solar wind ripple through with time.

Solar Orbiter has been given a path in resonance with Venus so it will visit many times, making use of Venus's gravity for adjustments. These will gradually push it out of the orbital plane of the planets so it can get an unprecedented view of the solar poles. It probably won't have such close company again, however. More detailed Venusian research will have to wait for NASA's recently approved Veritas mission.

Astonishingly, Mariner 2 made a close approach to Venus in 1962, only five years after the first-ever satellite was launched. Venera 1, launched days before Yuri Gagarin reached space, probably passed by even earlier, but had lost contact with ground control beforehand, so we'll never know. Back then, science fiction writers were still writing books set on a wet, but hospitable Venus. It was only in 1967 that Venera 4 revealed a surface temperature of 464°C (867°F).


These temperatures made Mars a much more attractive place to explore, both because probes don't melt, and the tantalizing possibility of life remains. 

If you want to get a direct view of the planet being visited, this is a great time, with Venus high and unmissably bright in the western sky after sunset. On Tuesday and Wednesday, it will be joined by the new Moon, for extra aesthetics.

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