posted 03-30-2015 11:26 AM               

BepiColombo launch moved to 2017

The launch of BepiColombo, an ESA mission to explore the planet Mercury in collaboration with the Japanese space agency, JAXA, is now planned to take place during a one month long window starting on 27 January 2017.

BepiColombo is an ambitious mission comprising two separate orbiters, the ESA-led Mercury Planetary Orbiter (MPO) and the JAXA-led Mercury Magnetospheric Orbiter (MMO), as well as a carrier spacecraft, known as the Mercury Transfer Module (MTM).

In recent months, all three spacecraft have passed important milestones, with the successful completion of MPO thermal vacuum tests at ESA's European Space Research and Technology Centre (ESTEC) in the Netherlands, and MMO environmental tests, in Japan, at the end of 2014. In February, the first mating of the MTM and MPO flight modules at ESTEC took place smoothly. These two spacecraft will soon be joined by the MMO, which is due to arrive at ESTEC next month.

During this period, a major review of BepiColombo – the Mission Critical Design Review – took place. This review, which examined all aspects of the design of the mission, was successfully completed on 25 March.

One aspect of the mission that was examined during the review period was the launch of BepiColombo, which had been targeted for a window opening in July 2016. However, as the result of delays in the procurement of critical units and the availability of some payloads, a decision was taken to opt for a later launch opportunity in order to minimize the operational risk to this ambitious dual mission.

The pre-launch test campaign for the spacecraft is now expected to be completed in December 2016, leading to a window for launch on an Ariane 5 from ESA's spaceport at Kourou, starting on 27 January 2017. Nevertheless, BepiColombo will still arrive at Mercury at the same time (January 2024) as if launched in mid-2016.

The spacecraft will reach Mercury using a highly efficient, low thrust, electric propulsion system that will steadily propel it along a series of arcs around the Sun. The trajectory will also be modified by eight planetary flybys.

BepiColombo will return to Earth's vicinity in July 2018, encounter Venus in 2019 and 2020, and then receive five gravity assists from Mercury itself between 2020 and 2023.

Once the spacecraft's speed has been slowed sufficiently by these maneuvers, the MTM will be jettisoned and BepiColombo will be captured by Mercury's gravity in January 2024. The MPO will then fire its chemical propulsion thrusters to lower the orbit before the European and Japanese craft separate and begin their different missions.

Once the orbiters are deployed in their separate orbits around the innermost planet, they will carry out the most comprehensive exploration of Mercury and its environment ever undertaken.

The two orbiters will explore Mercury for one Earth year (4 Mercury years), with the option of a one-year extension.

posted 07-07-2017 09:05 AM               

Preparing for Mercury: BepiColombo stack completes testing

ESA's Mercury spacecraft has passed its final test in launch configuration, the last time it will be stacked like this before being reassembled at the launch site next year.

BepiColombo's two orbiters, Japan's Mercury Magnetospheric Orbiter and ESA's Mercury Planetary Orbiter, will be carried together by the Mercury Transport Module. The carrier will use a combination of electric propulsion and multiple gravity-assists at Earth, Venus and Mercury to complete the 7.2 year journey to the Solar System's mysterious innermost planet.

Above: The complete BepiColombo spacecraft stack on 5 July 2017.

From bottom to top: the Mercury Transfer Module (sitting on top of a cone-shaped adapter, and with one folded solar array visible to the right); the Mercury Planetary Orbiter (with the folded solar array seen towards the left, with red protective cover), and the Mercury Magnetospheric Orbiter (MMO).

The Mercury Magnetospheric Orbiter's Sunshield and Interface Structure (MOSIF) that will protect the MMO during the cruise to Mercury is sitting on the floor to the right. (ESA/C. Carreau)

Once at Mercury, the orbiters will separate and move into their own orbits to make complementary measurements of Mercury's interior, surface, exosphere and magnetosphere. The information will tell us more about the origin and evolution of a planet close to its parent star, providing a better understanding of the overall evolution of our own Solar System.

To prepare for the harsh conditions close to the Sun, the spacecraft have undergone extensive testing both as separate units, and in the 6 m-high launch and cruise configuration.

One set of tests carried out earlier this year at ESA's technical centre in the Netherlands focused on deploying the solar wings, and the mechanisms that lock each panel in place. The 7.5 m-long array of the Mercury Planetary Orbiter and the two 12 m-long array of the Mercury Transport Module will be folded while inside the Ariane 5 rocket.

Last month, the full spacecraft stack was tested inside the acoustic chamber, where the walls are fitted with powerful speakers that reproduce the noise of launch.

Just last week, tests mimicked the intense vibrations experienced by a satellite during launch. The complete stack was shaken at a range of frequencies, both in up-down and side-to-side motions.

These were the final tests to be completed with BepiColombo in mechanical launch configuration, before it is reassembled again at the launch site.

In the coming weeks the assembly will be dismantled to prepare the transfer module for its last test in the thermal–vacuum chamber. This will check it will withstand the extremes of temperatures en route to Mercury.

The final 'qualification and acceptance review' of the mission is foreseen for early March. Then BepiColombo will be flown to Europe's Spaceport in Kourou, French Guiana, in preparation for the October 2018 departure window. The date will be confirmed later this year.

"This week was the last opportunity to see the spacecraft in its stacked launch configuration before it leaves Europe. The next time will be when we are at the launch site already fueled," says Ulrich Reininghaus, ESA's BepiColombo Project Manager. "This is quite a milestone for the project team. We are looking forward to completing the final tests this year, and shipping to Kourou on schedule."

posted 06-11-2018 11:29 AM               

MIO – Mercury Magnetospheric Orbiter's New Name

JAXA selected MIO as new name for the Mercury Magnetospheric Orbiter (MMO) to be launched this Japanese fiscal year. Selection process is based on public response to the MMO renaming project made during the designated correspondence period, February 20 to April 9, 2018. Following are the details:

• The definition of the word mio in the original Japanese is a waterway or fairway. It is a fitting name denoting how far the MMO mission has come, navigating its course past important research and development milestones. It also carries the connotation of wishing the spacecraft a safe journey.

• Historically, markers called mio-tsukushi were posted to guide boats sailing at rivers and sea. In traditional Japanese poetry, mio-tsukushi interchangeably means working hard without giving up. This describes the diligent and tenacious sprit of the MMO project team who never ceases to challenge.

• The spacecraft will travel through the solar wind, a continuous stream of plasma that the Sun emits in the Mercury's magnetosphere. The Mercury's magnetospheric interference constantly affects the state of the solar wind in orbit. It conjures up the image of a sea vessel underway with its bow heading forward.

• Mio is easy to say for many, especially those who do not speak Japanese.

Total number of correspondents: 6,494; 19 suggested Mio, 3 did Mio-Tsukushi.

BepiColombo, an ESA-JAXA joint mission to explore Mercury, comprises of two orbiters - the MPO, Mercury Planetary Orbiter and the MIO, Mercury Magnetosphere Orbiter. MPO aims at elucidating the surface and internal composition of Mercury. The MIO mission is observing the planet's magnetic field and magnetosphere.

JAXA is in charge of the development of the MIO spacecraft and controlling its operation at the target orbit, as Japan is adept at observations of magnetic field and magnetosphere. ESA controls BepiColombo launch and flight to Mercury and orbital insertions. The development and operation of the MPO is also part of the mission performed by ESA. Ariane 5 will launch the tandem satellites. After entering the planet's orbit, detached orbiters are scheduled for approximately year-long observation mission, which both agencies will cooperatively engage in.

posted 07-27-2018 08:28 AM               

BepiColombo to target mid-October launch

Europe's first mission to Mercury will target the early morning of 19 October for launch, Arianespace and ESA announced today.

The joint ESA-JAXA BepiColombo mission will launch on an Ariane 5 from Europe's Spaceport in Kourou, setting a trio of spacecraft on course for Mercury. The spacecraft will travel together: a transfer module will carry the two science orbiters – the ESA Mercury Planetary Orbiter and the JAXA Mercury Magnetospheric Orbiter – using a combination of solar power and electric propulsion, and nine gravity-assist flybys of Earth, Venus and Mercury.

Lift-off is anticipated for around 01:45 GMT (03:45 CEST), equivalent to 18 October 22:45 in local time (GFT).

The date chosen represents the first option to launch, taking into account some additional, unplanned testing performed in Kourou. The launch window remains open until 29 November.

"We have had a great start to our launch campaign in Kourou, and are on track for launch in less than ninety days," says ESA's BepiColombo project manager Ulrich Reininghaus.

"We have an incredibly packed schedule, but it is great to see our spacecraft building up together for the final time."

Since arriving at the Spaceport in May, many essential preparations have been completed. For example, the spacecraft have been fitted with their protective high-temperature blankets, xenon and nitrogen tanks have been checked, loaded and pressurised, and the deployment tests and final installations of the solar arrays are underway.

Simulations for key operations have also started at ESA's operations centre in Darmstadt, Germany. Personnel are also practicing non-routine events to be prepared for all eventualities on the journey to Mercury.

The composite spacecraft 'stack' will make the first flyby of Mercury just three years after launch. A number of scientific instruments will be active during the planetary flybys, with the transfer module's 'webcams' offering the potential to capture simple images before the main science camera is operational in Mercury orbit.

Once separated into their final orbits, the two scientific craft will make complementary measurements of the innermost planet and its environment, from its deep interior to its interaction with the solar wind, to provide the best understanding of Mercury to date. The results will provide insight into how the innermost planet of a solar system forms and evolves close to its parent star.

posted 10-19-2018 09:15 PM               

BepiColombo launches on ESA and JAXA mission to planet Mercury

For only the third time in history, a mission is now on its way to study the innermost planet of our solar system.

The European Space Agency (ESA) and Japan Aerospace Exploration Agency's (JAXA) joint BepiColombo mission launched on a seven-year journey to orbit the planet Mercury on Friday (Oct. 19). The mission's dual spacecraft, ESA's Mercury Planetary Orbiter (MPO) and JAXA's Mercury Magnetospheric Orbiter (MMO), along with the ESA-built Mercury Transfer Module (MTM), lifted off at 9:45 p.m. EDT (10:45 p.m. local time or 0145 GMT Oct. 20) from Ariane Launch Complex 3 (ELA-3) at Guiana Space Center, Europe's spaceport in Kourou, French Guiana.

posted 04-10-2020 09:00 AM               

BepiColombo takes last snaps of Earth en route to Mercury

The ESA/JAXA BepiColombo mission completed its first flyby on 10 April, as the spacecraft came less than 12 700 km from Earth's surface at 06:25 CEST, steering its trajectory towards the final destination, Mercury. Images gathered just before closest approach portray our planet shining through darkness, during one of humankind's most challenging times in recent history.

Launched in 2018, BepiColombo is on a seven-year journey to the smallest and innermost planet orbiting the Sun, which holds important clues about the formation and evolution of the entire Solar System.

Today's operation is the first of nine flybys which, together with the onboard solar propulsion system, will help the spacecraft reach its target orbit around Mercury. The next two flybys will take place at Venus and further six at Mercury itself.

While the manoeuvre took advantage of Earth's gravity to adjust the path of the spacecraft and did not require any active operations, such as firing thrusters, it included 34 critical minutes shortly after BepiColombo's closest approach to our planet, when the spacecraft flew across the shadow of Earth.

"This eclipse phase was the most delicate part of the flyby, with the spacecraft passing through the shadow of our planet and not receiving any direct sunlight for the first time after launch," said Elsa Montagnon, BepiColombo Spacecraft Operations Manager for ESA.

To prepare for the scheduled eclipse, mission operators fully charged the spacecraft batteries and warmed up all components in advance, then closely monitored the temperature of all onboard systems during the period in darkness, between 07:01 and 07:35 CEST.

"It is always nerve-wracking to know a spacecraft's solar panels are not bathed in sunlight. When we saw the solar cells had restarted to generate electrical current, we knew BepiColombo was finally out of Earth's shadow and ready to proceed on its interplanetary journey," added Elsa.

Space operations are never routine at ESA's mission control centre in Darmstadt, Germany, but today's flyby had one extra challenge. The manoeuvre, programmed long in advance and impossible to postpone, had to be prepared with limited on-site personnel, amid the social distancing measures adopted by the Agency in response to the ongoing coronavirus pandemic; but the restrictions had no impact on the operation's success.

As BepiColombo swung by our planet, most scientific instruments on ESA's Mercury Planetary Orbiter – one of the two science spacecraft that make up the mission – were switched on. Several sensors were also active on the second component of the mission, JAXA's Mercury Magnetospheric Orbiter, also known as Mio.

Scientists will use the data gathered during the flyby, which include images of the Moon and measurements of Earth's magnetic field as the spacecraft zipped past, to calibrate the instruments that will, as of 2026, investigate Mercury to solve the mystery of how the scorched planet formed.

"Today was of course very different to what we could have imagined only a couple of months ago," said Johannes Benkhoff, ESA's BepiColombo Project Scientist, who followed the operation from his home in the Netherlands, along with the many scientists from the 16 instrument teams that comprise the mission, scattered between Europe and Japan.

"We are all pleased that the flyby went well and that we could operate several scientific instruments, and we are looking forward to receiving and analysing the data. These will also be useful to prepare for the next flyby, when BepiColombo will swing past Venus in October."

"There is a great interest in Japan in the BepiColombo mission. Thus, after the successful flyby we are looking forward to the science at Venus and Mercury," said Go Murakami, BepiColombo Project Scientist at JAXA.

Our home from space

On 9 April, ahead of the flyby, and then again today, just before closing in, the BepiColombo monitoring cameras snapped a series of images of Earth from space, picturing our planet in these difficult times for humans across Europe and the world.

"These selfies from space are humbling, showing our planet, the common home that we share, in one of the most troubling and uncertain periods many of us have gone through," said Günther Hasinger, ESA's Director of Science, who also followed the event remotely from home, in Spain.

"We are scientists who fly spacecraft to explore the Solar System and observe the Universe in search of our cosmic origins, but before that we are humans, caring for one another and coping with a planetary emergency together. When I look at these images, I am reminded of the strength and resilience of humankind, of the challenges we can overcome when we team up, and I wish they bring you the same sense of hope for our future."

posted 10-15-2020 05:41 AM               

BepiColombo flies by Venus en route to Mercury

The ESA-JAXA BepiColombo mission has completed the first of two Venus flybys needed to set it on course with the Solar System's innermost planet, Mercury.

Above: BepiColombo images Venus during close approach. (ESA/BepiColombo/MTM)

The closest approach of the flyby took place at 03:58 GMT (05:58 CEST) this morning at a distance of about 10 720 km from the planet's surface.

Launched 20 October 2018, the spacecraft needs nine gravity assist flybys – one at Earth, two at Venus and six at Mercury before entering orbit around the planet in 2025. Flybys ultilise the gravitational pull of the planets to help alter the speed and direction of the spacecraft, and together with the spacecraft's solar electric propulsion system, help BepiColombo steer into Mercury orbit against the strong gravitational pull of the Sun.

The first flyby – of Earth – took place 10 April this year, returning poignant images of our home planet as the world faced lockdown due to the COVID-19 pandemic.

Flying by teleworking

"For the Venus flyby we conducted the large majority of our preparations over the last three months via teleworking, with only the minimum personnel required onsite during the flyby to ensure the safe operation of the spacecraft," says Elsa Montagnon, ESA's BepiColombo Spacecraft Operations Manager.

The on-site team at ESA's mission control centre in Darmstadt, Germany, comprised four members of the flight control team split into two groups over a period of 36 hours, together with a ground station manager, and two team members joining around closest approach to manage the images as they were downloaded from the spacecraft.

"The flyby itself was very successful," confirms Elsa. "The only difference to normal cruise phase operations is that near to Venus we have to temporarily close the shutter of any of the star trackers that are expected to be blinded by the planet, similar to closing your eyes to avoid looking at the Sun."

Two of the three monitoring cameras onboard the Mercury Transfer Module were activated during dedicated imaging slots from 20 hours before closest approach through to 15 minutes afterwards. From afar, Venus is seen as a small disc in the camera's field of view, close to the spacecraft body. During the closest approach phase the planet dominates the view, 'rising' behind the magnetometer boom of the Mercury Planetary Orbiter.

Above: BepiColombo's first Venus flyby. (ESA)

Science in the making

Seven of the eleven science instruments onboard the European Mercury Planetary Orbiter, plus its radiation monitor, and three of five onboard the Japanese Mercury Magnetospheric Orbiter were active during the flyby. While the suite of sensors are designed to study the rocky, atmosphere-free environment at Mercury, the flyby offered a unique opportunity to collect valuable science data at Venus.

"Following the successful Earth flyby where our instruments worked even better than expected, we are looking forward to see what will come out of the Venus flyby," says Johannes Benkhoff, ESA's BepiColombo Project Scientist.

"We'll have to be patient while our Venus specialists look carefully into the data, but we hope to be able to provide some atmosphere temperature and density profiles, information about the chemical composition and cloud cover, and on the magnetic environment interaction between the Sun and Venus. But we rather anticipate more results next year than now, given the closer flyby distance, so watch this space!"

The 2021 flyby, planned for 10 August, will see the spacecraft pass within just 550 km of the planet's surface.

Telescope teamwork

Above: BepiColombo's first glimpse of Venus. (ESA/BepiColombo/MTM)

Today's encounter also provided the chance to make simultaneous measurements with JAXA's Akatsuki Venus Climate Orbiter and its Earth-orbiting Hisaki Spectroscopic Planet Observatory, together with ground-based observatories to study Venus from multiple viewpoints and at different scales.

"Akatsuki is currently the only spacecraft in orbit around Venus and because of its elliptical orbit it was actually 30 times further away from the planet than BepiColombo during the flyby, meaning we can compare close observations of BepiColombo with Akatsuki's global-scale view," says Go Murakami, JAXA's BepiColombo Project Scientist.

"A large campaign of coordinated observations are ongoing, involving professional and amateur astronomers alike, that will build a three-dimensional picture of what's happening over time in Venus' atmosphere, something that cannot be achieved by one spacecraft or one telescope alone," says Valeria Mangano, of the National Institute for Astrophysics in Italy, and chair of the Venus flyby working group.

Next steps

While the science teams are busy diving into the new flyby data, the operations teams will assess the performance of the Venus flyby and make a routine trajectory correction of the spacecraft on 22 October. The next dedicated solar electric propulsion arc is planned for May 2021.

BepiColombo will also make its first Mercury flyby next year, in October, at a distance of just 200 km, providing the first tantalizing taste of what will follow once the mission's two science orbiters have arrived in their dedicated orbits around the planet. There they will study Mercury's mysteries, addressing numerous open questions in planetary science, such as: where in the Solar System did Mercury form? What is the nature of the ice in Mercury's shadowed craters? Is the planet still geologically active? How can such a small planet still have a magnetic field?

"With each flyby completed we get a step closer to answering some of these perplexing questions about mysterious planet Mercury," adds Johannes. "Learning more about Mercury will shed light on the history of the entire Solar System, helping us to better understand our own place in space."

"While gravity assists have a practical function to set us on course for Mercury, it is wonderful to have these brief opportunities to observe Venus as we fly through the Solar System," says Simon Plum, ESA's Head of Mission Operations.

"Thanks to the teams who have been working hard behind the scenes over the last months to make this flyby a success. While we work with incredibly far distances and a tremendous amount of space as we navigate the Solar System, we are again dealing with special operations under pandemic situation, where space between our people matter and the safety of our colleagues remain the number one priority."

posted 08-11-2021 09:37 AM               

BepiColombo skims past Venus

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.

posted 10-02-2021 10:13 AM               

Hello Mercury

The joint European-Japanese BepiColombo mission captured this view of Mercury on 1 October 2021 as the spacecraft flew past the planet for a gravity assist maneuver.

The image was taken at 23:44:12 UTC by the Mercury Transfer Module's Monitoring Camera 2, when the spacecraft was about 2418 km from Mercury. Closest approach of about 199 km took place shortly before, at 23:34 UTC. In this view, north is towards the lower right. The cameras provide black-and-white snapshots in 1024 by 1024 pixel resolution.

The region shown is part of Mercury's northern hemisphere including Sihtu Planitia that has been flooded by lavas. A round area smoother and brighter than its surroundings characterizes the plains around the Calvino crater, which are called the Rudaki Plains.The 166 km-wide Lermontov crater is also seen, which looks bright because it contains features unique to Mercury called 'hollows' where volatile elements are escaping to space. It also contains a vent where volcanic explosions have occurred. BepiColombo will study these types of features once in orbit around the planet.

The gravity assist manoeuvre was the first at Mercury and the fourth of nine flybys overall. 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 help steer on course for Mercury orbit in 2025.

The Mercury Transfer Module carries two science orbiters: ESA's Mercury Planetary Orbiter and JAXA's Mercury Magnetospheric Orbiter, which from complementary orbits will study all aspects of mysterious Mercury from its core to surface processes, magnetic field and exosphere, to better understand the origin and evolution of a planet close to its parent star.

posted 06-19-2023 03:18 PM               

BepiColombo braces for third Mercury flyby

The ESA/JAXA BepiColombo mission is gearing up for its next close flyby of Mercury on 19 June, when it will pass the planet's surface at an altitude of about 236 km.

This is the third of six gravity assist flybys at Mercury that ESA's spacecraft operation team is guiding BepiColombo through. The flybys, together with more than 15 000 hours-worth of challenging solar electric propulsion operations, are needed to help the spacecraft fight against the enormous gravitational pull of our Sun, so that it can eventually lose enough energy to be captured into Mercury's orbit in 2025.

Above: The image was taken by BepiColombo's monitoring camera 1 at 10:32 UT (12:32 CEST) 19 June when the spacecraft was still about 121 000 km away from Mercury, but it is rapidly closing in on the planet for a close flyby of about 236 km altitude at 20:34 BST / 21:34 CEST tonight. BepiColombo will make its closest approach on the night side of the planet. Mercury is seen just below centre of the image, its day and night side clearly visible. (ESA/BepiColombo/MTM)

The closest approach of Monday's flyby will take place at 19:34 UTC (21:34 CEST). BepiColombo will approach on the night side of the planet, meaning the most interesting views of Mercury's surface will be recorded by the spacecraft's monitoring cameras from about 13 minutes later. The first images are expected to be released on 20 June.

Flybys and thrusters

While a welcome opportunity to snap images and fine-tune science instrument operations at Mercury before the main mission begins, the primary reason for the flyby is to use the planet's gravity to guide BepiColombo's path through the inner Solar System.

The mission launched into space on an Ariane 5 from Europe's Spaceport in Kourou in October 2018 and is making use of nine planetary flybys: one at Earth, two at Venus, and six at Mercury, to help steer into Mercury orbit.

After this flyby, the mission will enter a very challenging part of its journey to Mercury, gradually increasing the use of solar electric propulsion through additional propulsion periods called 'thrust arcs' to continually brake against the enormous gravitational pull of the Sun. These thrust arcs can last from a few days up to two months, with the longer arcs interrupted periodically for navigation and manoeuvre optimisation.

Cosmic slingshot

Mercury is the least explored rocky planet of the Solar System, with one of the main reasons being that getting there is really difficult. As BepiColombo gets closer to the Sun, the powerful gravitational pull of our host star accelerates the spacecraft towards it.

Gravity assist flybys are a great way to change course using very little fuel, but they are far from simple.

Above: Key moments during BepiColombo’s third Mercury flyby on 19 June 2023. (ESA)

Flight controllers are ready to precisely guide BepiColombo so that it passes Mercury at exactly the right distance, from the right angle, and with the right velocity. All of this was calculated years ago, but has to be as close to perfect as possible on the day.

"As BepiColombo starts feeling Mercury's gravitational pull, it will be travelling at 3.6 km/s with respect to the planet. That's just over half the speed it approached with during the previous two Mercury flybys," explains ESA flight dynamics expert Frank Budnik.

"And this is exactly what the point of such events is. Our spacecraft began with far too much energy because it launched from Earth and, like our planet, is orbiting the Sun. To be captured by Mercury, we need to slow down, and we're using the gravity of Earth, Venus and Mercury to do just that."

On 19 May, teams at mission control performed the largest chemical propulsion manoeuvre the mission has seen. The purpose was to correct errors in BepiColombo's orbit that had accumulated as a result of thruster outages during the previous one-and-a-half month-long, slow electric propulsion arc. Correction manoeuvres on the approach to a flyby are part of normal operations; without this one BepiColombo would be 24 000 km too far from Mercury and on the wrong side of the planet!

To be on the safe side, and to ensure no chance the mission could end up on a collision course with Mercury, the latest manoeuvre was designed so that BepiColombo would pass the rocky planet at a slightly higher altitude than needed. The extra margin was a good bet and cancelled out previous errors that had crept in as the spacecraft traversed millions of kilometres through space. One week out from the flyby BepiColombo is now predicted to pass the planet's surface at an altitude of 236 km (+/- 5 km).

At the moment of close approach BepiColombo will have accelerated to 5.4 km/s with respect to Mercury courtesy of the planet's gravitational pull, but the flyby will overall reduce the spacecraft's velocity magnitude compared to the Sun by 0.8 km/s, and change its direction by 2.6 degrees.

"This is the first time that the complex solar electric propulsion method is being used to get a spacecraft to Mercury, and it represents a big challenge during the remaining part of the cruise phase," says Santa Martinez Sanmartin, ESA's BepiColombo mission manager. "We have already adapted our operations concept to have additional communications passes with our ground stations, enabling us to recover faster from thruster interruptions and to improve orbit determination. And all the while this is working with communications delays of more than ten minutes due to the time it currently takes light signals to travel between Earth and the spacecraft."

Flight dynamics is both a science and an art. Orbits, manoeuvres and flybys are determined years in advance, but spacecraft are not perfect mathematical objects. This is why teams always err on the side of caution, factoring in multiple opportunities for manoeuvres to hone and correct a spacecraft's actual path.

Tastes of science

While many instruments have been activated during the cruise phase, some will also operate during the flyby, providing another tantalising glimpse of the Mercury science expected during the main mission. Magnetic, plasma and particle monitoring instruments will sample the environment before, during and after closest approach.

This will be the first flyby for which the BepiColombo Laser Altimeter (BELA) and Mercury Orbiter Radio-science Experiment (MORE) will be switched on, albeit in the case of BELA for functional test purposes only. Once in Mercury orbit, BELA will measure the shape of Mercury's surface, and MORE will investigate Mercury's gravitational field and core.

"Collecting data during flybys is extremely valuable for the science teams to check their instruments are functioning correctly ahead of the main mission," says ESA's BepiColombo project scientist Johannes Benkhoff. "It also provides a novel opportunity to compare with data collected by NASA's MESSENGER spacecraft during its 2011–2015 mission at Mercury from complementary locations around the planet not usually accessible from orbit. We are delighted to already have data published based on our previous flybys that generated new science results, which makes us even more excited to get into orbit!"

Upon arrival at Mercury in December 2025, BepiColombo's two science modules – ESA's Mercury Planetary Orbiter (MPO) and JAXA's Mercury Magnetospheric Orbiter (MMO) – will separate from the Mercury Transfer Module (MTM) and enter complementary orbits around the planet.

The main science camera is shielded until the spacecraft modules separate but during flybys snapshots are taken by BepiColombo's monitoring cameras.

A unique selfie

During the closest approach, BepiColombo will be in Mercury's shadow. The illuminated part of the planet will only enter the spacecraft's field of view around 13 minutes later, when BepiColombo is at a distance of about 1840 km.

That means there will be no illuminated images from closest approach itself. The most visually appealing images showing the details of Mercury's surface will be captured between about 13 and 23 minutes after close approach.

The cameras provide black-and-white snapshots in 1024 x 1024 pixel resolution. Because of their position on the spacecraft, they also capture one of MTM's solar arrays and the MPO's antennas in the foreground of the images. As BepiColombo passes Mercury, we will see the planet appear in the top right of the M-CAM 3 images and move towards the bottom left.

The first images will be downlinked within a couple of hours after closest approach and are expected to be available for public release from the afternoon of 20 June onwards. The closest images are expected to reveal a host of prominent geological features including large craters, volcanic and tectonic terrain.

All images will also be released in ESA's Planetary Science Archive in the following days.

posted 06-20-2023 02:20 PM               

A trio of images highlight BepiColombo's third Mercury flyby

The ESA/JAXA BepiColombo mission has made its third of six gravity assist flybys at Mercury, snapping images of a newly named impact crater as well as tectonic and volcanic curiosities as it adjusts its trajectory for entering Mercury orbit in 2025.

The closest approach took place at 19:34 UTC (21:34 CEST) on 19 June 2023, about 236 km above the planet's surface, on the night side of the planet.

"Everything went very smoothly with the flyby and images from the monitoring cameras taken during the close approach phase of the flyby have been transmitted to the ground," says Ignacio Clerigo, ESA's BepiColombo Spacecraft Operations Manager.

"While the next Mercury flyby isn't until September 2024, there are still challenges to tackle in the intervening time: our next long solar electric propulsion 'thruster arc' is planned to start early August until mid-September. In combination with the flybys, the thruster arcs are critical in helping BepiColombo brake against the enormous gravitational pull of the Sun before we can enter orbit around Mercury."

Geological curiosities

During last night's close encounter, monitoring camera 3 snapped tens of images of the rocky planet. The images, which provide black-and-white snapshots in 1024 x 1024 pixel resolution, were downloaded overnight until early this morning. Three 'early release' images are presented here.

Above: Mercury starts appearing from the night side at the top right of this image taken by the ESA/JAXA BepiColombo mission on 19 June 2023 as the spacecraft sped by for its third of three gravity assist manoeuvres at the planet. (ESA/BepiColombo/MTM)

Approaching on the nightside of the planet, a few features started to appear out of the shadows about 12 minutes following the closest approach, when BepiColombo was already about 1800 km from the surface. The planet's surface became more optimally illuminated for imaging from about 20 minutes after close approach and onwards, corresponding to a distance of about 3500 km and beyond. In these closer images, a bounty of geological features are visible, including a newly named crater.

Crater named for artist Edna Manley

A large 218 km-wide peak-ring impact crater visible just below and to the right of the antenna in the two closest images presented here has just been assigned the name Manley by the International Astronomical Union's Working Group for Planetary System Nomenclature after Jamaican artist Edna Manley (1900–1987).

"During our image planning for the flyby we realised this large crater would be in view, but it didn't yet have a name," explains David Rothery, Professor of Planetary Geosciences at the UK's Open University and a member of the BepiColombo MCAM imaging team. "It will clearly be of interest for BepiColombo scientists in the future because it has excavated dark 'low reflectance material' that may be remnants of Mercury's early carbon-rich crust. In addition, the basin floor within its interior has been flooded by smooth lava, demonstrative of Mercury's prolonged history of volcanic activity."

While not apparent in these flyby images, the nature of the dark material associated with Manley Crater and elsewhere will be explored further by BepiColombo from orbit. It will seek to measure just how much carbon it contains and what minerals are associated with it, in order to learn more about Mercury's geological history.

Above: A bounty of geological features, including the newly named Manley impact crater, are visible in this image of Mercury taken by the ESA/JAXA BepiColombo mission on 19 June 2023 as the spacecraft sped by for its third of three gravity assist manoeuvres at the planet. (ESA/BepiColombo/MTM)

Snaking scarps

In the two closest images one of the most spectacular geological thrust systems on the planet can be seen close to the terminator of the planet, just to the bottom right of the spacecraft's antenna. The escarpment, called Beagle Rupes, is an example of one of Mercury's many lobate scarps, tectonic features that probably formed as a result of the planet cooling and contracting, causing its surface to become wrinkled like a drying out apple.

Beagle Rupes was first seen by NASA's Messenger mission during its initial flyby of the planet in January 2008. It is about 600 km in total length, and cuts through a distinctive elongated crater named Sveinsdóttir.

Beagle Rupes bounds a slab of Mercury's crust that has been thrust westwards by at least 2 km over the adjacent terrain. The scarp curves back at each end more strongly than most other examples on Mercury.

In addition, many nearby impact basins have been flooded by volcanic lavas, making this a fascinating region for follow-up studies by BepiColombo.

The complexity of the topography is well displayed, with shadows accentuated close to the day-nightside boundary, providing a feeling for the heights and depths of the various features.

Members of the BepiColombo imaging team are already having a lively debate about the relative influences of volcanism and tectonism shaping this region.

"This is an incredible region for studying Mercury's tectonic history," says Valentina Galluzzi of Italy's National Institute for Astrophysics (INAF). "The complex interplay between these escarpments shows us that as the planet cooled and contracted it caused the surface crust to slip and slide, creating a variety of curious features that we will follow up in more detail once in orbit."

Farewell 'hugs'

As BepiColombo moved farther from the planet it appears to nestle between the spacecraft's antenna and body from the perspective seen in these images. A 'farewell Mercury' sequence of images was also taken from afar as BepiColombo receded from the planet; these will be downloaded tonight.

Above: BepiColombo appears to 'hug' Mercury in this image taken by the ESA/JAXA BepiColombo mission on 19 June 2023 as the spacecraft sped by for its third of three gravity assist manoeuvres at the planet. (ESA/BepiColombo/MTM)

In addition to images, numerous science instruments were switched on and operating during the flyby, sensing the magnetic, plasma and particle environment around the spacecraft, from locations not normally accessible during an orbital mission.

"Mercury's heavily cratered surface records a 4.6 billion year history of asteroid and comet bombardment, which together with unique tectonic and volcanic curiosities will help scientists unlock the secrets of the planet's place in Solar System evolution," says ESA research fellow and planetary scientist Jack Wright, also a member of the BepiColombo MCAM imaging team.

"The snapshots seen during this flyby, MCAM's best yet, set the stage for an exciting mission ahead for BepiColombo. With the full complement of science instruments we will explore all aspects of mysterious Mercury from its core to surface processes, magnetic field and exosphere, to better understand the origin and evolution of a planet close to its parent star."

What's next?

BepiColombo's next Mercury flyby will take place on 5 September 2024, but there is plenty of work to occupy the teams in the meantime.

The mission will soon enter a very challenging part of its journey, gradually increasing the use of solar electric propulsion through additional propulsion periods called 'thrust arcs' to continually brake against the enormous gravitational pull of the Sun. These thrust arcs can last from a few days up to two months, with the longer arcs interrupted periodically for navigation and manoeuvre optimisation.

The next arc sequence will start in early August and last for about six weeks.

"We are already working intensively on preparing for this long thruster arc, increasing communications and commanding opportunities between the spacecraft and ground stations, to ensure a fast turnaround between thruster outages during each sequence," says Santa Martinez Sanmartin, ESA's BepiColombo mission manager.

"This will become more critical as we enter the final stage of the cruise phase because the frequency and duration of the thrust arcs will increase significantly – it will be almost continuous during 2025 – and it is essential to keep on course as accurately as possible."

BepiColombo's Mercury Transfer Module will complete over 15,000 hours of solar electric propulsion operations over its lifetime, which together with nine planetary flybys in total – one at Earth, two at Venus, and six at Mercury – will guide the spacecraft towards Mercury orbit. The ESA-led Mercury Planetary Orbiter and the JAXA-led Mercury Magnetospheric Orbiter modules will separate into complementary orbits around the planet, and their main science mission will begin in early 2026.

posted 05-15-2024 04:24 PM               

Glitch on BepiColombo: work ongoing to restore spacecraft to full thrust

BepiColombo, the joint ESA/JAXA mission to Mercury, has experienced an issue that is preventing the spacecraft's thrusters from operating at full power.

BepiColombo is a three-part spacecraft consisting of two scientific probes and the Mercury Transfer Module, which are designed to separate from one another as part of the mission's Mercury orbit insertion operations.

The solar arrays and electric propulsion system on the Mercury Transfer Module are used to generate thrust during the spacecraft's complex journey from Earth to Mercury.

However, on 26 April, as BepiColombo was scheduled to begin its next manoeuvre, the Transfer Module failed to deliver enough electrical power to the spacecraft's thrusters.

A combined team from ESA and the mission's industrial partners set to work the moment the issue was identified. By 7 May, they had restored BepiColombo's thrust to approximately 90% of its previous level. However, the Transfer Module's available power is still lower than it should be, and so full thrust cannot yet be restored.

The team's current priorities are to maintain stable spacecraft propulsion at the current power level and to estimate how this will affect upcoming manoeuvres. Work continues in parallel to identify the root cause of the issue and to maximise the power available to the thrusters.

The BepiColombo Flight Control Team working at ESA's ESOC mission control centre in Darmstadt, Germany, has arranged additional ground station passes in order to closely monitor the spacecraft and react rapidly if needed.

If the current power level is maintained, BepiColombo should arrive at Mercury in time for its fourth gravity assist at the planet in September this year. Final orbit insertion at Mercury is scheduled for December 2025 and the start of routine science operations for Spring 2026.

Updates will be shared as new information becomes available.

posted 09-05-2024 08:34 AM               

Fourth Mercury flyby begins BepiColombo's new trajectory

Teams from across ESA and industry have worked continuously over the past four months to overcome a glitch that prevented BepiColombo's thrusters from operating at full power. The ESA/JAXA mission is still on track, with a new trajectory took it just 165 km from Mercury's surface on Wednesday (4 Sept).

Taking BepiColombo closer to Mercury than it's ever been before, this flyby reduced the spacecraft's speed and changed its direction. It also gave us the opportunity to snap images and fine-tune science instrument operations at Mercury before the main mission begins. Closest approach occurred at 23:48 CEST (21:48 UTC).

Above: A "sneak preview" of an image captured during BepiColobo's fourth flyby of Mercury. (ESA/BepiColombo/MTM)

BepiColombo launched into space in October 2018 and is making use of nine planetary flybys: one at Earth, two at Venus, and six at Mercury, to help steer itself into orbit around Mercury. Once in orbit, the main science phase of the mission can begin.

This flyby was the fourth at Mercury. Whilst it was always in the schedule, BepiColombo got around 35 km closer to Mercury than originally planned, due to a new route devised by ESA's flight dynamics team.

Why is it so hard to visit Mercury?

Mercury is the least explored rocky planet of the Solar System, mainly because getting there is incredibly challenging. As BepiColombo gets closer to the Sun, the powerful gravitational pull of our star accelerates the spacecraft towards it. What's more, the spacecraft launched from Earth with a lot of energy, travelling far too quickly to be captured into orbit around little Mercury.

Overcoming both of these hurdles would be enormously difficult using onboard thrusters alone. So BepiColombo also makes use of gravity assist flybys to help it lose energy and slow down enough to eventually be captured into orbit around Mercury.

BepiColombo's journey to Mercury becomes even more epic

BepiColombo is unique in that it comprises two science orbiters that will circle Mercury – ESA's Mercury Planetary Orbiter and the Japan Aerospace Exploration Agency's (JAXA) Mercury Magnetospheric Orbiter. The two are carried together to the mysterious planet by the Mercury Transfer Module (MTM). In April 2024, BepiColombo started experiencing an issue that prevented MTM's electric thrusters from operating at full power.

Engineers identified unexpected electric currents between MTM's solar array and the unit responsible for extracting power and distributing it to the rest of the spacecraft. Onboard data imply that this is resulting in less power available for electric propulsion.

ESA's BepiColombo Mission Manager, Santa Martinez explains: "Following months of investigations, we have concluded that MTM's electric thrusters will remain operating below the minimum thrust required for an insertion into orbit around Mercury in December 2025."

A workaround to MTM's reduced thrust has been cleverly devised by ESA's Flight Dynamics team. They conceived a new trajectory that maintains the baseline scientific mission at Mercury but allows the spacecraft to use lower thrust during the cruise phase of the mission. With this new trajectory, BepiColombo is now expected to arrive at Mercury in November 2026.

Each of BepiColombo's fourth, fifth (December 2024) and sixth (January 2025) Mercury flybys are going ahead as planned. All three will change the spacecraft's speed and direction, bringing it more in tune with the orbit of Mercury around the Sun.

MTM will fire its thrusters in September to October 2024 to put BepiColombo onto its new trajectory. The fourth flyby took BepiColombo closer than planned to Mercury, helping reduce the propulsion needed to reach the fifth flyby. The sixth flyby will then be used to branch onto the new trajectory.

Science at Mercury: a teaser of what's to come

Beyond the later arrival date, the rest of the BepiColombo mission is expected to go ahead as planned, and the scientific objectives will not be affected. ESA expects the same science to come out of the mission, with data gathered by a suite of 16 instruments across the two orbiters.

Ten of these instruments were operated during this week's flyby, giving us another taste of what scientific discoveries we can expect from the main mission. Magnetic, plasma and particle monitoring instruments sampled the environment before, during and after closest approach. The other instruments cannot be operated because their fields of view are blocked by the carrier spacecraft.

"It's so exciting that BepiColombo can boost our understanding and knowledge of Mercury during these brief flybys, despite being in 'stacked' cruise configuration," says Johannes Benkhoff, BepiColombo Project Scientist.

"We get to fly our world-class science laboratory through diverse and unexplored parts of Mercury's environment that we won't have access to once in orbit, while also getting a head start on preparations to make sure we will transition into the main science mission as quickly and smoothly as possible."

Testing out the instruments during flybys is valuable for the science teams to check that their instruments are functioning correctly ahead of the main mission.

BepiColombo's best view yet of Mercury

BepiColombo's main science camera is shielded until the ESA and JAXA orbiters separate, but during flybys images are taken by the three monitoring cameras (M-CAMs) on the Mercury Transfer Module.

The cameras provide black-and-white 1024x1024 pixel snapshots. Their images of Mercury are a bonus: the cameras were actually designed to monitor the spacecraft's solar array, antenna and magnetometer boom, especially in the challenging period after launch.

As BepiColombo passed Mercury, well-lit images began to be taken by M-CAM 2 and M-CAM 3 two minutes after closest approach, when BepiColombo was around 200 km from Mercury's surface. M-CAM 1 had a beautiful view of Mercury receding into the distance.

This flyby was also the first to take BepiColombo over Mercury's poles, helping to adjust the spacecraft's trajectory to match that of Mercury, which is inclined compared to Earth's orbit. We expect to be able to share BepiColombo's first stunning views of the planet's south pole.

The first images were downlinked a few hours after closest approach and were released on 5 September. The closest images are expected to reveal large craters, wrinkle ridges, lava plains and much more, helping scientists unlock the secrets of Mercury's 4.6-billion-year history and its place in the evolution of the Solar System.

All images are scheduled to be released publicly in the Planetary Science Archive later in September. The first science results from data collected during the flyby will be released on 13 September.