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Raumfahrt - ESA Solar Orbiter Proba-3 Mission -Update-4

5.07.2020

Solar Orbiter commissioned in orbit despite Covid-19

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Airbus has successfully completed the In-Orbit Commissioning (IOC) of the European Space Agency’s (ESA) Solar Orbiter spacecraft, by the teams working from home as a result of the Covid-19 pandemic.

At 165 million km away from Earth, Solar Orbiter is definitely keeping its social distance, but its commissioning presented a challenge to the teams who would normally work together in the office to complete the IOCprocess. Instead, under the leadership of Airbus project Manager Ian Walters, the team met online at least once a day to make sure the process was tackled quickly and efficiently.

Ian Walters, project manager for Solar Orbiter at Airbus said: “In the four months since launch we have been keeping an eye on every move to make sure Solar Orbiter performs as it should. If someone had told me in February that we would be doing the in-orbit commissioning while working from home I would have been horrified – but in the event the teams all worked perfectly together online and we achieved it without a hitch.”

ESA confirms that the IOC has been completed on time by the Airbus prime team and it is believed that this is the first “virtual” ESA Mission Commissioning Results Review (MCRR).

Immediately after launch from Cape Canaveral on 10th February 2020 Airbus began closely monitoring the spacecraft, testing all systems, all the spare units and the 10 instruments including the Solar Wind Plasma Analyser (SWA) which will measure the solar winds’ properties and composition.

Checks were carried out to verify that the next phase of the mission could start and that ESA’s Operations Centre (ESOC) was ready to take full control of the mission.

After successfully making its first close pass of the Sun on 15 June at 77 million kilometres, Solar Orbiter’s next major step is a Venus fly by on 27th December this year. It will use the gravity of the planet to first reduce the distance to the Sun and then gradually shift the spacecraft’s orbit out of the ecliptic plane. The full science phase of the mission is due to start in March 2022.

About Solar Orbiter

Solar Orbiter’s mission is to perform unprecedented close-up observations of the Sun and from high-latitudes, providing the first images of the uncharted polar regions of the Sun, and investigating the Sun-Earth connection. The spacecraft carries 10 state-of-the-art instruments. Remote sensing payloads will perform high-resolution imaging of the Sun’s “atmosphere” as well as the solar disc. Other instruments will measure the solar wind and the solar magnetic fields in the vicinity of the orbiter. This will provide unprecedented insight into how our parent star works in terms of the 11-year solar cycle, and how we can better predict periods of stormy space weather.

Quelle: AirbusSpace

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Update: 10.07.2020

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N° 13–2020: Call for Media: ESA to reveal first images from Solar Orbiter

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First images from ESA’s Solar Orbiter to be revealed:

The first images from ESA’s new Sun-observing spacecraft Solar Orbiter will be released to the public on 16 July 2020. Media representatives are invited to watch an online press briefing, which will take place at 14:00 CEST (13:00 BST), and talk to the scientists behind the mission.

Solar Orbiter, launched on 10 February, completed its commissioning phase in mid-June and performed its first close approach to the Sun. Shortly thereafter, the European and US science teams behind the mission’s 10 instruments were able to test the entire instrument suite in concert for the first time.

- Better than expected

Despite the setbacks the teams faced while commissioning the spacecraft and its instruments amid the COVID-19 pandemic, the first imaging campaign has been a great success.

“The first images are exceeding our expectations,” says Daniel Müller, Solar Orbiter Project Scientist at ESA. “We can already see hints of very interesting phenomena that we have not been able to observe in detail before. The 10 instruments on board Solar Orbiter work beautifully, and together provide a holistic view of the Sun and the solar wind. This makes us confident that Solar Orbiter will help us answer profound open questions about the Sun.”

- We have never been closer with a camera

No other images of the Sun have been taken from such a close distance. During its first perihelion, the point in the spacecraft’s elliptical orbit closest to the Sun, Solar Orbiter got as close as 77 million kilometres from the star’s surface, about half the distance between the Sun and Earth. The spacecraft will eventually make much closer approaches to the Sun. The spacecraft is now in its cruise phase, gradually adjusting its orbit around the Sun. Once in its science phase, which will commence in late 2021, the spacecraft will get as close as 42 million kilometres from the Sun’s surface, closer than the planet Mercury. The spacecraft’s operators will gradually tilt Solar Orbiter’s orbit to enable the probe to get the first proper view of the Sun’s poles.

- An international mission

Solar Orbiter is a space mission of international collaboration between ESA and NASA. Twelve ESA Member States (Austria, Belgium, the Czech Republic, France, Germany, Italy, Norway, Poland, Spain, Sweden, Switzerland, and the United Kingdom) as well as NASA contributed to the science payload. Denmark, Finland, Greece, Ireland, Luxembourg, the Netherlands and Portugal contributed to building the spacecraft but not to the science payload.

Additional information for media in the UK and Ireland:

The UK played a key role in development of the Solar Orbiter mission. The spacecraft was built by Airbus Defence and Space in Stevenage. British scientists are involved in four out of the ten instruments aboard the spacecraft. Researchers from Imperial College London and the UCL Mullard Space Science Laboratory (UCL MSSL) lead the teams behind Solar Orbiter’s Magnetometer (MAG) and Solar Wind Analyser (SWA) respectively. UCL also has a key role in the Extreme Ultraviolet Imager (EUI), which will enable the scientists to study processes on the Sun in greater detail than ever before. STFC RAL Space led the consortium that developed and built the extreme ultraviolet imaging spectrometer SPICE

UK Space Agency media contacts:
Gareth Bethell – UK Space Agency
Gareth.bethell@ukspaceagency.gov.uk

In Ireland, ENBIO developed the black coating for the heat shield, an enabling technology for the mission.

For contributions from the other Member states, please refer to the translated version of the Call for Media here.

Event programme

Members of the public can watch an online press briefing at https://www.esa.int/esawebtv on Thursday 16 July at 14:00 CEST (13:00 BST).

Among the speakers will be:

Daniel Müller – Solar Orbiter Project Scientist at ESA

Holly R. Gilbert – Solar Orbiter Project Scientist at NASA

David Berghmans – Royal Observatory of Belgium, Principal Investigator of the Extreme Ultraviolet Imager (EUI)

Sami Solanki – Director of the Max Planck Institute for Solar System Research, Principal Investigator of the Polarimetric and Helioseismic Imager (PHI)

Christopher J. Owen – Mullard Space Science Laboratory, University College London, Principal Investigator of the Solar Wind Analyser (SWA)

Jose-Luis Pellon-Bailon –  Solar Orbiter Deputy Spacecraft Operations Manager

Media representatives with valid press credentials should register via https://www.esa.int/Contact/mediaregistration by Wednesday 15 July 12:00 CEST.

Questions to the panel can be asked via media@esa.int.

Quelle: ESA

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Update: 17.07.2020

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Solar Orbiter’s first images reveal ‘campfires’ on the Sun

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The first images from Solar Orbiter, a new Sun-observing mission by ESA and NASA, have revealed omnipresent miniature solar flares, dubbed ‘campfires’, near the surface of our closest star.

According to the scientists behind the mission, seeing phenomena that were not observable in detail before hints at the enormous potential of Solar Orbiter, which has only just finished its early phase of technical verification known as commissioning.

“These are only the first images and we can already see interesting new phenomena,” says Daniel Müller, ESA’s Solar Orbiter Project Scientist. “We didn’t really expect such great results right from the start. We can also see how our ten scientific instruments complement each other, providing a holistic picture of the Sun and the surrounding environment.”

Solar Orbiter, launched on 10 February 2020, carries six remote-sensing instruments, or telescopes, that image the Sun and its surroundings, and four in situ instruments that monitor the environment around the spacecraft. By comparing the data from both sets of instruments, scientists will get insights into the generation of the solar wind, the stream of charged particles from the Sun that influences the entire Solar System.

The unique aspect of the Solar Orbiter mission is that no other spacecraft has been able to take images of the Sun’s surface from a closer distance.

Closest images of the Sun reveal new phenomena

First views of the Sun obtained with Solar Orbiter's EUI on 30 May 2020, revealing the omnipresent miniature eruptions dubbed 'campfires'.
First views of the Sun obtained with Solar Orbiter's EUI on 30 May 2020, revealing the omnipresent miniature eruptions dubbed 'campfires'.

The campfires shown in the first image set were captured by the Extreme Ultraviolet Imager (EUI) from Solar Orbiter’s first perihelion, the point in its elliptical orbit closest to the Sun. At that time, the spacecraft was only 77 million km away from the Sun, about half the distance between Earth and the star.

“The campfires are little relatives of the solar flares that we can observe from Earth, million or billion times smaller,” says David Berghmans of the Royal Observatory of Belgium (ROB), Principal Investigator of the EUI instrument, which takes high-resolution images of the lower layers of the Sun’s atmosphere, known as the solar corona. “The Sun might look quiet at the first glance, but when we look in detail, we can see those miniature flares everywhere we look.”

The scientists do not know yet whether the campfires are just tiny versions of big flares, or whether they are driven by different mechanisms. There are, however, already theories that these miniature flares could be contributing to one of the most mysterious phenomena on the Sun, the coronal heating.

Unravelling the Sun’s mysteries

One of the newly found campfires in an image from Solar Orbiter's EUI. The circle in the lower left corner indicates the size of Earth for scale.
One of the newly found campfires in an image from Solar Orbiter's EUI. The circle in the lower left corner indicates the size of Earth for scale.

“These campfires are totally insignificant each by themselves, but summing up their effect all over the Sun, they might be the dominant contribution to the heating of the solar corona,” says Frédéric Auchère, of the Institut d'Astrophysique Spatiale (IAS), France, Co-Principal Investigator of EUI.

The solar corona is the outermost layer of the Sun’s atmosphere that extends millions of kilometres into outer space. Its temperature is more than a million degrees Celsius, which is orders of magnitude hotter than the surface of the Sun, a ‘cool’ 5500 °C. After many decades of studies, the physical mechanisms that heat the corona are still not fully understood, but identifying them is considered the ‘holy grail’ of solar physics.

“It’s obviously way too early to tell but we hope that by connecting these observations with measurements from our other instruments that ‘feel’ the solar wind as it passes the spacecraft, we will eventually be able to answer some of these mysteries,” says Yannis Zouganelis, Solar Orbiter Deputy Project Scientist at ESA.

Seeing the far side of the Sun

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Complementary views of the Sun and its outer atmosphere, or corona, based on the EUI, PHI, Metis and SoloHi instruments on Solar Orbiter.
Access the video

The Polarimetric and Helioseismic Imager (PHI) is another cutting-edge instrument aboard Solar Orbiter. It makes high-resolution measurements of the magnetic field lines on the surface of the Sun. It is designed to monitor active regions on the Sun, areas with especially strong magnetic fields, which can give birth to solar flares.

During solar flares, the Sun releases bursts of energetic particles that enhance the solar wind that constantly emanates from the star into the surrounding space. When these particles interact with Earth’s magnetosphere, they can cause magnetic storms that can disrupt telecommunication networks and power grids on the ground.

The Sun and its magnetic properties observed by the PHI instrument on Solar Orbiter.
The Sun and its magnetic properties observed by the PHI instrument on Solar Orbiter.

“Right now, we are in the part of the 11-year solar cycle when the Sun is very quiet,” says Sami Solanki, the director of the Max Planck Institute for Solar System Research in Göttingen, Germany, and PHI Principal Investigator. “But because Solar Orbiter is at a different angle to the Sun than Earth, we could actually see one active region that wasn’t observable from Earth. That is a first. We have never been able to measure the magnetic field at the back of the Sun.”

The magnetograms, showing how the strength of the solar magnetic field varies across the Sun’s surface, could be then compared with the measurements from the in situ instruments.

“The PHI instrument is measuring the magnetic field on the surface, we see structures in the Sun’s corona with EUI, but we also try to infer the magnetic field lines going out into the interplanetary medium, where Solar Orbiter is,” says Jose Carlos del Toro Iniesta, PHI Co-Principal Investigator, of Instituto de Astrofísica de Andalucía, Spain.

Catching the solar wind

Combining remote-sensing observations from SPICE with in situ measurements from SWA.
Combining remote-sensing observations from SPICE with in situ measurements from SWA.

The four in situ instruments on Solar Orbiter then characterise the magnetic field lines and solar wind as it passes the spacecraft.

Christopher Owen, of University College London Mullard Space Science Laboratory and Principal Investigator of the in situ Solar Wind Analyser, adds, “Using this information, we can estimate where on the Sun that particular part of the solar wind was emitted, and then use the full instrument set of the mission to reveal and understand the physical processes operating in the different regions on the Sun which lead to solar wind formation.”

“We are all really excited about these first images – but this is just the beginning,” adds Daniel. “Solar Orbiter has started a grand tour of the inner Solar System, and will get much closer to the Sun within less than two years. Ultimately, it will get as close as 42 million km, which is almost a quarter of the distance from Sun to Earth.”

“The first data are already demonstrating the power behind a successful collaboration between space agencies and the usefulness of a diverse set of images in unravelling some of the Sun’s mysteries,” comments Holly Gilbert, Director of the Heliophysics Science Division at NASA Goddard Space Flight Center and Solar Orbiter Project Scientist at NASA. 

A 'family portrait' of the first images and data from Solar Orbiter's ten instruments.
A 'family portrait' of the first images and data from Solar Orbiter's ten instruments.

Solar Orbiter is a space mission of international collaboration between ESA and NASA. Nineteen ESA Member States (Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Italy, Ireland, Luxembourg, the Netherlands, Norway, Poland, Portugal Spain, Sweden, Switzerland, and the United Kingdom), as well as NASA, contributed to the science payload and/or the spacecraft. The satellite was built by prime contractor Airbus Defence and Space in the UK.

Quelle: ESA

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Update: 23.12.2020

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Europe's Solar Orbiter is headed for a holiday flyby of Venus

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An artist's depiction of the Solar Orbiter spacecraft skimming past Venus.
(Image: © ESA/ATG medialab)

Solar Orbiter won't be home for the holiday, but at least it has Venus. The spacecraft will tackle an important milestone as its operators and scientists on Earth mark the holiday season.

 

Solar Orbiter, a joint project of the European Space Agency (ESA) and NASA, launched in February on a mission to capture the best-ever images of our sun, including its elusive poles. But getting close to the star at the heart of our solar system is a difficult endeavor, so the spacecraft needs to slalom around a few planets to set its course properly. The first of those flybys, which visits Venus, will occur on Dec. 27.

 

"Just as the majority of us will remain safely at home under various COVID-19 pandemic lockdown measures during what is traditionally a holiday period, the flyby — a routine event in the world of flying spacecraft — will also be monitored by the spacecraft operations managers remotely as well," ESA personnel wrote in a statement.

Solar Orbiter's closest approach this month will bring the spacecraft about 4,700 miles (7,500 kilometers) above Venus' atmosphere; later similar passages will bring the spacecraft much closer, as it maneuvers closer to the sun.

 
 

In addition to dragging the spacecraft in toward the sun, the flybys are also coordinated to pull Solar Orbiter at a tilt out of the ecliptic plane, which holds the sun and the planets. It's this tilt that will let the spacecraft peer at the sun's poorly studied poles.

 

During the flyby, the spacecraft must continue pointing toward the sun, so the telescopes on Solar Orbiter won't be able to snap images of Venus. However, a subset of the instruments that analyze the immediate environment of the spacecraft will be at work.

Quelle: SC

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Update: 4.08.2021

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TWO SPACE PROBES TO PASS BY VENUS NEXT WEEK

Two spacecraft are heading for a close Venus encounter: Solar Orbiter passes by on August 9th and BepiColombo on August 10th.

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Venus is a brilliant beacon in the western sky after sunset right now. Look toward it and you will be looking at three spacecraft as well: Japan’s Akatsuki orbiter and two others, both European, that are fast approaching for their second gravity-assist flybys. Solar Orbiter passes by on August 9th and BepiColombo on August 10th. Both plan lots of science throughout their close encounters — and they are looking for amateurs’ photography to bolster their coordinated science campaigns.

The two spacecraft are using Venus to steer them toward their eventual science targets. Both are approaching Venus from its night side, with the planet appearing as only the thinnest of crescents. But the flybys will achieve different results. After passing 7,995 km (4,968 miles) above Venus’s surface on August 9th at 4:42 UT (Earth received time), Solar Orbiter will speed outward from the Sun, aimed at a November 26th encounter with Earth. The Earth flyby will place it into its operational science orbit, beginning its prime mission.

Five more Venus encounters over the ensuing years will pump up the inclination of its orbit, allowing the probe to view the Sun’s poles. Only Ulysses has explored high solar inclinations within Jupiter’s orbit before, and Ulysses had no camera; Solar Orbiter, traveling much closer, will give us wondrous views.

NAVIGATING A FLYBY

BepiColombo, for its part, has to lose speed in order to drop in toward Mercury’s orbit. It will pass just ahead of Venus in its orbit on the way to a flyby at an altitude of 552 km on August 10th at 13:48 UT.

No spacecraft has passed so close to Venus since the end of the Venus Express mission in 2014. The many low-altitude orbits Venus Express took near the end of its mission have provided the European Space Agency (ESA) with a detailed understanding of Venus’s upper atmosphere, giving them confidence in handling their Mercury orbiter’s close passage.

Venus’s gravity will tug backward on the spacecraft, slowing it down and sending it on a path inside the planet’s orbit. Distances in the inner solar system being short, BepiColombo will fly past Mercury only 52 days later, on October 1st.

INTO THE MAGNETOSPHERE

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Akatsuki will observe Venus throughout the two flybys from the slowest, most distant part of its orbit, where it will monitor the behavior of Venus’s magnetosphere from a stable position. Venus, unusually for a planet, has no internally generated magnetic field. However, the solar wind interacts with the upper atmosphere, inducing a magnetic field. Where the solar magnetic field slams into Venus’ field, there is a bow shock, stretching out into a long magnetotail behind Venus. Solar Orbiter and BepiColombo will approach Venus from inside the magnetotail and pass across the bow shock just 33 hours apart, providing an unprecedented opportunity to directly measure how an induced magnetic field changes with time.

Both spacecraft have huge suites of instruments specially designed for studies of magnetic fields and the charged particles that travel within them, so the science payoff should be rich. Out in front of BepiColombo, Solar Orbiter will be able to measure variations in the solar magnetic field before they hit Venus’ field. Working together, the spacecraft will see how Venus’ magnetosphere responds to the Sun, nearly in real time.

All of Solar Orbiter’s fields and particles instruments will be powered on and operating in order to study the magnetic and charged-particle environment around Venus. Most of its cameras are intended for direct solar viewing so will not be able to image Venus during the encounter. The exception is SoloHI, a wide-angle, monochrome, visible-light camera that will usually be aimed off the disk of the Sun to capture the solar corona; it will image Venus’ nightside on approach.

BepiColombo will perform similar fields and particles measurements while inside the magnetotail. The extremely close pass also provides a test of the Italian Spring Accelerometer, designed to probe the deep interior of the planets by measuring subtle variations in the local force of gravity.

Around and after closest approach, BepiColombo will view Venus’s sunlit side, and the imaging instruments will get to work. MERTIS will get multispectral views until an hour after the flyby, using many wavelengths to penetrate the atmosphere to different depths. But the most fun images will come from the MCAMs, engineering cameras designed for spacecraft navigation and health checkups. MCAM2 and MCAM3 both look across parts of the spacecraft to space beyond. They’ll begin imaging three minutes before closest approach. MCAM2 will lose sight of Venus soon after, so will only take pictures for 22 minutes, but MCAM3 will watch Venus recede for 37 hours after the flyby.

ESA shares MCAM data to the web within 10 days of acquisition. Even before the images are released, ESA posts the metadata – image time and other information – which lets the public know how well the flyby has succeeded. Watch the ESA Planetary Science Archive to see when new images have landed! In an article posted today, ESA says that the first batch of BepiColombo image data will arrive in the evening of August 10th (European time), with most arriving on August 11th.

Quelle: Sky&Telescope

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Update: 7.08.2021

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European Space Agency prepares for back-to-back flybys of Venus

Missions with Nasa and Jaxa will use planet’s pull to lose energy, allowing spacecraft to fall closer to sun

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The European Space Agency is preparing for back-to-back flybys of the same planet by two different spacecraft just one day apart.

On 9 August, the Esa-Nasa Solar Orbiter spacecraft will fly past Venus with a closest approach of 7,995km (4,968 miles). A day later, the Esa-Jaxa BepiColombo mission will make its pass at an altitude of just 550km (342 miles).

 

Flying close to a planet is known as a gravitational assist. This is because such flybys were first used to increase the orbital energy of a spacecraft, slingshotting it further into the solar system.

But here, both missions will use the manoeuvre to lose energy, allowing them to fall closer to the sun. In the case of Solar Orbiter, the gravity of Venus will help alter its orbital inclination, eventually allowing the spacecraft to see the poles of the sun.

BepiColombo’s ultimate destination is the planet Mercury, the closest planet to the sun. Using gravitational assists from Earth, Venus and Mercury, Bepi will execute the delicate manoeuvre of dropping into orbit around the tiny planet, a difficult task considering Mercury is deep in the Sun’s mighty gravitational field. Data collected during the flybys will be combined with Jaxa’s Akatsuki mission, which is currently in orbit around Venus.

Quelle: The Guardian

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Update: 11.08.2021

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BepiColombo skims past Venus

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BepiColombo, which comprises ESA's Mercury Planetary Orbiter and the Mercury Magnetospheric Orbiter of the Japan Aerospace Exploration Agency (JAXA), is scheduled to reach its target orbit around the smallest and innermost planet of the Solar System in 2025.

The joint European-Japanese BepiColombo mission captured this view of Venus on 10 August 2021 as the spacecraft passed the planet for a gravity assist manoeuvre.

The image was taken at 13:57:56 UTC by the Mercury Transfer Module's Monitoring Camera 3, when the spacecraft was 1573 km from Venus. Closest approach of 552 km took place shortly before, at 13:51:54 UTC.

The cameras provide black-and-white snapshots in 1024 x 1024 pixel resolution. The image has been lightly processed to enhance contrast and use the full dynamic range. A small amount of optical vignetting is seen in the bottom left of the image.

The high-gain antenna of the Mercury Planetary Orbiter and part of the body of the spacecraft are visible in front of Venus, at top left.

The manoeuvre, the second at Venus and the third of nine flybys overall, helped steer the spacecraft on course for Mercury. During its seven-year cruise to the smallest and innermost planet of the Solar System, BepiColombo makes one flyby at Earth, two at Venus and six at Mercury to brake against the gravitational pull of the Sun in order to enter orbit around Mercury. Its first Mercury flyby will take place 1-2 October 2021.

BepiColombo, which comprises ESA's Mercury Planetary Orbiter and the Mercury Magnetospheric Orbiter of the Japan Aerospace Exploration Agency (JAXA), is scheduled to reach its target orbit around the smallest and innermost planet of the Solar System in 2025.

Quelle: SD

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Update: 31.08.2021

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BepiColombo, Solar Orbiter collect data on Venus during historic double flyby

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On August 9, 2021, the joint ESA/NASA Solar Orbiter spacecraft performed a flyby of Venus, coming within 7,995 km of the Venusian surface. Just 33 hours later, on August 10, the joint ESA/JAXA BepiColombo spacecraft flew by the planet, coming within 552 km of the surface.

The historic double flyby was a result of the two spacecraft attempting to reduce their orbital energy while en route to their respective destinations. BepiColombo is traveling to Mercury, where it will study the planet in-depth, while Solar Orbiter is finishing its last flybys before entering the correct orbital inclination to best observe the Sun. 

 

The double flybys required great accuracy and precise deep-space network coordination to ensure the two trajectories did not cross. During the flyby, both BepiColombo and Solar Orbiter collected data on Earth’s sister planet.

Venusian imagery

Both Solar Orbiter and BepiColombo are equipped with cameras; however, they are not high-resolution. Nonetheless, their science cameras were able to capture black-and-white images — showing the planet’s immense brightness and full cloud coverage. 

 

 

Solar Orbiter’s SoloHI imager, used primarily to image the solar wind, or the charged particle streams ejected from the surface of the Sun, was used on the Venus flyby to observe the nightside of the planet during the approach.

BepiColombo, like Solar Orbiter, used a suite of three science cameras to collect imagery of the planet as well. The spacecraft collected images throughout the entire flyby.

The full set of BepiColombo images from the flyby can be found in ESA’s Planetary Science Archive.

BepiColombo feels Venus’ heat

Venus is the solar system’s hottest planet, and it was expected that when BepiColombo came within 552 km of the surface on the dayside of the planet it would experience a temperature increase on its instruments and systems. 

JAXA’s contribution to the BepiColombo mission, the Mercury Magnetospheric Orbiter (MMO), recorded a temperature increase of 110ºC on one of the module’s eight solar panels. The panel’s temperature changed from -100ºC to a +10ºC at the time of closest approach.

ESA infographic showing where BepiColombo captured images during the flyby. (Credit: ESA/BepiColombo/MTM)

However, inside the spacecraft, the temperature only increased 2-3ºC, proving that the spacecraft’s insulation is effective. 

On ESA’s Mercury Transfer Module (MTM), the temperature increased by 50ºC on an onboard radiator. The Mercury Planetary Orbiter (MPO) recorded a temperature change of about 20ºC.

Strong Venusian gravity

To stay pointing on course, both BepiColombo and Solar Orbiter use reaction wheels to maintain their orientation. These wheels spin faster at times when the spacecraft is experiencing periods of intense gravitational pull like they did during the Venus flyby. 

The Italian Spring Accelerometer (ISA) instrument on the MPO module of BepiColombo collected data on the spacecraft’s acceleration with great sensitivity.

Using data from the angular momentum of the reaction wheels during the flyby, the BepiColombo ISA instrument team translated the acceleration data into a frequency audible to the human ear. 

 

 

Additionally, the ISA was able to detect the effects of tidal forces on BepiColombo from Venus. This marked the first time an accelerometer recorded the effects of tidal forces on a spacecraft at another planet. 

The BepiColombo and ISA teams will use this data to fine-tune the instrument ahead of its use at Mercury.

Comparing magnetometer data

During their respective flybys, both spacecraft collected data on Venus using their magnetometers. This provided the Solar Orbiter and BepiColombo teams the unique ability to compare data between the two spacecraft. Specifically, the ability to compare solar wind interaction with Venus’ atmosphere.

The BepiColombo team took the data from the MPO magnetometer and created a simple sonification of the variability of the magnetic field. The audio from the sonification presents low-frequency wind-like noises from the solar wind’s interaction with the Venusian atmosphere. 

BepiColombo’s transition into calm solar wind at the bow shock, the location where a planet’s magnetosphere meets the solar wind, was clearly recorded.

 

 

The Solar Orbiter magnetometer data was similar to that of BepiColombo’s, showing the magnetic field was increasing in magnitude during approach due to the compression of the magnetic field. As the spacecraft crossed the bow shock, the magnitude sharply decreased.

Teams from both of the missions are currently undertaking a detailed analysis of the two datasets from the flyby.

Ions in the magnetosphere

Sensors on BepiColombo’s MPO and MMO modules monitored ions circulating in the Venusian magnetosphere. The Search for Exospheric Refilling and Emitted Natural Abundances (SERENA) and Planetary Ion Camera (PICAM) instruments on the MPO module measured a peak in hydrogen ion density during BepiColombo’s closest approach to Venus (552 km).

With an encounter this close, the MPO module’s MErcury Radiometer and Thermal infrared Imaging Spectrometer (MERTIS) instrument could capture atmospheric spectra of Venus while the planet filled its field of view. 

This kind of high-resolution spectra data had not been obtained since the Soviet Union’s Venera 15 mission in the early 1980s. 

 

From the data, an expected band of carbon dioxide and other spectral features was seen. A full analysis of the data and the atmosphere’s thermal structure will take weeks to complete.

Like the ISA, the use of MERTIS at Venus helped fine-tune the instrument before its use at Mercury, where it will perform the first-ever thermal infrared observations of the planet by a spacecraft. 

BepiColombo is expected to perform its first of six flybys of Mercury on October 1, 2021. In 2025, BepiColombo will release the two planetary orbiters it is carrying into Mercury’s orbit, where they will study all aspects of the solar system’s smallest planet.

Solar Orbiter is currently expected to complete its final flyby of Earth on November 27, where it will pass just 460 km above the surface. After the flyby, the spacecraft will be in the correct orbital inclination to study the Sun, and Solar Orbiter’s primary mission will begin. 

It will continue to perform flybys of Venus for the duration of its mission to increase its orbital inclination for optimal observation of the Sun’s unknown polar regions. 

Quelle: NS

 

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