The European Space Agency (ESA) announced last week that its spacecraft BepiColombo – launched from Earth in October 2018 on a roundabout journey to planet Mercury – will be visible to astronomers on the night of April 9-10, 2020. This will be BepiColombo’s first and only Earth flyby. It’ll be using Earth’s gravity to speed it up and alter its course slightly, then send it on its way toward its target planet in the inner solar system.
As for viewing the spacecraft in the sky, people in the Southern Hemisphere will have the best view of the spacecraft – through telescopes – as it passes relatively high in the sky. Meanwhile, observers as far south on Earth’s globe as the southern U.S. states of Florida and Texas might also catch the spacecraft, with telescopic aid, crossing lower in the night sky. ESA said:
By the time of the flyby, BepiColombo will have travelled almost 1.4 billion km [about 870 million miles] – roughly nine times the distance between Earth and the sun – since the European-Japanese mission was launched in October 2018. Yet, passing over at an altitude of just 12,700 km [about 8,000 mi], it will come within just a couple of thousand kilometers [1,300 mi] of our planet’s exosphere, the outermost layer of the atmosphere, providing us with the last chance to say hello – and goodbye.
BepiColombo is a joint mission of ESA and the Japan Aerospace Exploration Agency (JAXA). The April 9-10, 2020, flyby will be the first of a series of nine gravity assists that BepiColombo will use to reach its final destination, Mercury. It will arrive at Mercury in late 2025. ESA said:
The next two flybys will see BepiColombo proceed towards Venus in October 2020 and August 2021, respectively, followed by six flybys of Mercury itself to further adjust the trajectory. Eventually, the mission’s two science orbiters – ESA’s Mercury Planetary Orbiter and Mio, the Mercury Magnetospheric Orbiter of the Japan Aerospace Exploration Agency (JAXA) – will separate from the Mercury Transfer Module in late 2025 and start their scientific operations at Mercury in early 2026.
ESA said its mission scientists plan to use the flyby to test some of the instruments aboard the spacecraft, adding:
The operation, however, will be performed with limited personnel at ESA’s European Space Operations Centre (ESOC) in Darmstadt, Germany, where engineers will have to comply with social distancing rules presently in place all over Europe as a response to the coronavirus pandemic.
Elsa Montagnon, BepiColombo Spacecraft Operations Manager at ESA, added:
The Earth swing-by is a phase where we need daily contact with the spacecraft. This is something that we cannot postpone. The spacecraft will swing by Earth independently in any case.
Observing a relatively close object in the sky from different locations will produce a slight difference in the view from different parts of Earth. Thus the spacecraft will appear closer to or farther from a fixed star, as seen from different perspectives or countries. We have included some sample viewing charts to help you find the spacecraft moving in front of the stars (using binoculars or a small telescope). NOTE: The times given on these charts are local times, the time on your clock as seen from the various places mentioned in the charts. Eddie Irizarry, who created these charts for EarthSky, commented:
I double-checked these times for each country and also verified in Google the current time in each of these countries, to confirm if they are, or are not, using daylight time.
Bottom line: On the night of April 9-10, 2020, BepiColombo will pass 7,891 miles (12,700 km, about 1 Earth diameter) from Earth’s surface. For most of us, it’ll pass unseen. But people with telescopes will spot it! How to spot BepiColombo on its roundabout journey to Mercury – charts and more – here.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Prior to that, she had worked for the University of Texas McDonald Observatory since 1976, and created and produced their Star Date radio series. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. In 2020, she won the Education Prize from the American Astronomical Society, the largest organization of professional astronomers in North America. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.
Eddie Irizarry of the Sociedad de Astronomía del Caribe (Astronomical Society of the Caribbean) has been a NASA Solar System Ambassador since 2004. He loves public outreach and has published multiple astronomy articles for EarthSky, as well as for newspapers in Puerto Rico. He has also offered dozens of conferences related to asteroids and comets at the Arecibo Observatory.
Asteroid 33012EddieIrizarry, a 7.8 km space rock, has been named in his honor.
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