The mercury-bound BepiColombo spacecraft will observe Venus during today's pass in search of phosphine and sulfur dioxide.
The joint spacecraft BepiColombo of the Japan-European Space Agency is making a scheduled pass near Venus tonight while the cloud-shrouded planet was hugely popular in the news.
The flyby is part of a complex series of passes the spaceship must make in order to arrive in orbit around Mercury on Christmas Day, December 25, 2025. BepiColombo was launched on October 20, 2018 with an Ariane 5 rocket from the Guyana Space Center and will fly by on April 10, 2020 earlier this year.
Update: The Venus flyby last night was successful, and heads of mission in Darmstadt report that BepiColombo is on the right track. The spaceship even posed for a quick selfie with Venus in the background:
Venus, during the flyby on October 15th. ESA / BepiColombo / MTM
Tonight's closest approximation is set at 11:58 p.m. EDT / 3:58 UT at 10,800 kilometers from the surface of Venus. BepiColombo will then make a much narrower pass of 630 kilometers through Venus on August 11, 2021 next year. After that, BepiColombo will make six passes near Mercury before entering orbit in late 2025. BepiColombo will only be the second spaceship (after NASA's Mercury MESSENGER) to orbit the innermost world.
ESA Operations will live tweet the flyby this evening from 3:30 p.m. UT / 11:30 p.m. EDT.
Today's Venus Flyby … Credit: ESA
BepiColombo is actually two spaceships on one platform: the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO). The spaceship is named after the 20th century scientist Giuseppe ‘Bepi’ Colombo, who first proposed the use of gravity aids in planetary missions.
Observations made during the brief flyby are used to calibrate instruments and supplement measurements made by Earth observation sites and the Japanese Akatsuki spaceship, which is currently the only active mission on the station around Venus.
"Overlapping or complementary viewing geometries from the three locations BepiColombo, Akatsuki and Earth lead to complete global (day and night side) views of the atmosphere over several atmospheric levels at the same time," Johannes Benkhoff (ESA) told Universe Today. "MERTIS observations will help investigate the radiation equilibrium of Venus, the atmospheric structure, chemical processes at the cloud level and the influence of global atmospheric waves on the weather patterns of Venus."
The BepiColombo stack is preparing for launch. Photo credit: ESA / CNES / Arianespace
The flyby comes just a month after astronomers announced the detection of phosphine in the Venusian atmosphere. What is ironic is that researchers originally used Venus as a baseline measurement as an example of a sterile world when the detection was done. On earth, phosphine is reactive and is only replenished by volcanic activity and life. However, Venus would require higher levels of volcanic activity than we know to produce the amounts of phosphine observed in the study.
An artistic impression of volcanism on Venus. NASA / JPL-Caltech / Peter Rubin
BepiColombo has a detector for measuring the phosphine content: the mercury radiometer and the thermal infrared spectrometer (MERTIS). While MERTIS may not hit the 20 parts per billion threshold needed during today's distant pass, it could serve as a test run for Venus' narrow pass next year and offer much better prospects.
However, MERTIS can detect another chemical compound that is able to shed light on another aspect of the puzzle: sulfur dioxide, which could point to recent volcanic activity on Venus.
"With the observed phosphine levels, our chances of today's flyby are very slim." says Jörn Helbert (German Institute for Planetary Research at the Aerospace Center). “It would have to be significantly more than previously reported in order to be observed by MERTIS. During the second flyby we have a slightly better situation. "
"We will be able to measure sulfur dioxide." Helbert continued. "The contents of this gas in the atmosphere of Venus have changed considerably in the last few decades and could indicate active volcanism."
The Planetary Virtual Observatory Laboratory (PVOL) is also calling for amateur observations to support scientific observations made during today's flyby.
Modern amateurs can use ultraviolet filters to bring out current details in the Venusian cloud cover. Photo credit: Roger Hutchinson
Venus could become the target of future missions in the next decade. First and foremost could be the Rocket Labs proposed Venus mission, which includes a modified version of their small Photon spacecraft set to fly to Venus in 2023. Other proposed missions are the NASA proposed Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy (VERITAS) mission, the Deep Atmosphere Venus study of noble gases, the chemistry study (DAVINCI +) and the Bio-Inspired Ray for Extreme Environments mission and Zonal Exploration (BREEZE). Another interesting concept, ESA's Venus orbiter EnVision, could hit the market in the 2030s.
You can currently see Venus and wave to BepiColombo low in the morning sky. As a plus, Venus will be accompanied by the ultimate target Mercury of the dawn mission at the end of October. If you have binoculars (and they don't go away) then you should definitely look for Comet C / 2020 P1 NEOWISE from + 8 the East.
Looking east on the morning of October 31st. Image credit: Stellarium
Follow the BepiColombo tonight for a quick look at Venus, a planet that is sure to be the subject of scientific study for the next decade.
Lead Image Credit: An artistic impression of BepiColombo past Venus. Photo credit: ESA / ATG MediaLab