It is hardly an exaggeration to say that 2021 will be the year of Mars.

Two successful landings, two new probes in orbit, a rover in search of traces of life, the first flight of a motorized helicopter - there were many occasions to let your thoughts wander in amazement towards the red deserts of our neighboring planet.

The great fascination with Mars is not new, however.

A multitude of missions, a broad spectrum of research results on its structure and history, perhaps also the visual similarity to terrestrial landscapes and at the same time the profound difference of the conditions there make Mars the planet that is closest to us, at least in terms of media.

Much closer than our other neighbor, Venus, at least.

Sibylle Anderl

Editor in the features section.

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    Venus enthusiastic researchers have long complained about this asymmetry. Fifty years ago, the journal Nature Physical Science pointed out that the focus on Mars was contrary to the intentions of the American National Academy of Sciences. Their space science advisory board ultimately provides missions to as many different planets as possible.

    In fact, at the time, the exploration of Venus was dominated by Soviet mission programs. The Venera 4, 5 and 6 probes had descended into the Venusian atmosphere. In 1970, the Soviet probe Venera 7 even managed to make a soft landing on the surface of Venus for the first time. Until then, in 1962 with Mariner 2 and 1967 with Mariner 5, the Americans had only been able to collect scientific data in flyby flights. On the other hand, NASA was planning two orbiters (Mariner 8 and 9) and a landing mission (Viking 1) for Mars at the beginning of 1971. “Was Venus unjustifiably ignored?” Was the rhetorical question asked at the time, in order to emphasize the meteorological findings to be expected from Venus as worthwhile.Its dense and cloudy atmosphere, as a counterpart to the thin and cloudless Martian atmosphere, could provide important information for a general understanding of atmospheric dynamics and development.

    The complaint about a scientifically neglected Venus has lasted for decades. It was heard again in recent years, even if there have been quite a few missions there since then - most recently on NASA's part since 1990 with the Magellan orbiter and flyby of the probes Galileo, Cassini and Mercury Messenger in 1990, 1999 and 2005. The The European Space Agency ESA provided important data with the Venus Express as an orbiter from 2006 to 2014. The Japanese Akatsuki probe has orbited Venus since 2015.

    Nevertheless: When in 2017 two proposed Venus programs were eliminated in the final round of the future NASA Discovery missions against two asteroid missions, the disappointment about a supposedly underestimated Venus in its scientific potential was again great. The science magazine Science speculated that the missions might lack the right selling point. The search for life on Venus is out of the question in view of the prevailing conditions, and neither is the possibility of future astronautical development. A better understanding of earthly climate change through the study of the heated Venus is also not a good argument under the Trump administration to finance a Venus mission after more than 30 years. At most the ideaUsing knowledge about Venus for the study of distant exoplanets is promising.

    At that time nobody suspected that the argumentation would soon change unexpectedly. In September 2020, a study appeared in Nature Astronomy in which astronomers claimed to have found a possible indication of the existence of microorganisms in the Venusian atmosphere with the detection of the gas monophosphane (PH3) in the Venusian atmosphere. The media hustle and bustle was enormous. The scientific claim quickly lost its persuasiveness after a subsequent examination - the data analysis turned out to be flawed, and the interpretation of the find as a biomarker was by no means compelling - but the discussion undoubtedly provided a boost to supporters of other Venus missions.