Tag: science

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The 3 m-long magnetometer boom of the Solar wind Magnetosphere Ionosphere Link Explorer (Smile) is deployed under helium-filled balloons to simulate the weightlessness conditions of space.

Smile is a joint mission between ESA and the Chinese Academy of Sciences (CAS) and will aim to build a more complete understanding of the Sun-Earth connection by measuring the solar wind and its dynamic interaction with the magnetosphere.

The structural and thermal model of the Smile payload module is currently undergoing testing at the European Space Research and Technology Centre (ESTEC) in Noordwijk, the Netherlands. Missions frequently come ‘home’ to ESA’s technical heart to be put through the rigours of launch and the space environment to confirm they are ready for operating in the harsh conditions of space.

The magnetometer boom deployment followed a thermal vacuum test and successfully verified its functionality, an important step in the mission’s test campaign.

Once in space, the sensors on the magnetometer boom will provide in-situ magnetic measurements around the spacecraft. The 3 m-long boom is necessary to minimize the magnetic perturbations from the spacecraft and allow precise measurement of the environment. It is one of four instrument suites for in-situ characterisation (ions and magnetic field) and imaging (soft X-ray and UV) of Earth’s magnetosphere.

The magnetometer is provided by CAS, who is responsible for three scientific instruments, the platform, the mission and science operations. ESA is responsible for the Payload Module, the launch vehicle, one of the scientific instruments and part of the science operations.

Despite Covid travelling restrictions sadly preventing the Chinese team from being physically present, they were able to follow with a real-time video stream. The success of the test is the latest demonstration of the close and good cooperation among the European and Chinese teams involved in Smile.

The payload module has now moved to Airbus (Madrid, Spain) for mechanical testing. Following the conclusion of that test campaign, it will then be shipped to China in March for integration on the platform for spacecraft-level qualification, during which the boom will be deployed once again.

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Our galaxy, the Milky Way, began forming around 12 billion years ago. Since then, it has been growing in both mass and size through a sequence of mergers with other galaxies.

Perhaps most exciting is that this process has not quite finished, and by using data from ESA’s Gaia spacecraft, astronomers can see it taking place. This in turn allows to reconstruct the history of our galaxy, revealing the ‘family tree’ of smaller galaxies that has helped make the Milky Way what it is today.

The latest work on this subject comes from Khyati Malhan, a Humboldt Fellow at the Max-Planck-Institut für Astronomie, Heidelberg, Germany, and colleagues. Together, they have analysed data based on Gaia’s early third data release (EDR3) looking for the remains of smaller galaxies merging with our own. These can be found in the so-called halo of the Milky Way, which surrounds the disc of younger stars and central bulge of older stars that comprise the more luminous parts of the Milky Way.

When a foreign galaxy falls into our own, great gravitational forces known as tidal forces pull it apart. If this process goes slowly, the stars from the merging galaxy will form a vast stellar stream that can be easily distinguished in the halo. If the process goes quickly, the merging galaxy’s stars will be more scattered throughout the halo and no clear signature will be visible.

But the merging galaxy may contain more than just stars. It could also be surrounded by a population of globular star cluster and small satellite galaxies. So, the team looked for these in the Gaia data.

In total they studied 170 globular clusters, 41 stellar streams and 46 satellites of the Milky Way. Plotting them according to their energy and momentum revealed that 25 percent of these objects fall into six distinct groups. Each group is a merger taking place with the Milky Way. There was also a possible seventh merger in the data.

Five had been previously identified on surveys of stars. They are known as Sagittarius, Cetus, Gaia-Sausage/Enceladus, LMS-1/Wukong, and Arjuna/Sequoia/I’itoi. But the sixth was a newly identified merger event. The team called it Pontus, meaning the sea. In Greek mythology, Pontus is the name of one of the first children of Gaia, the Greek goddess of the Earth.

Based upon the way Pontus has been pulled apart by the Milky Way, Khyati and colleagues estimate that it probably fell into the Milky Way some eight to ten billion years ago. Four of the other five merger events likely also took place around this time as well. But the sixth event, Sagittarius, is more recent. It might have fallen into the Milky Way sometime in the last five to six billion years. As a result, the Milky Way has not yet been able to completely disrupt it.

Piece by piece, astronomers are fitting together the merger history of the Galaxy, and Gaia data is proving invaluable.

On 13 June 2022, the Gaia mission will issue its data release 3, which will provide even more detailed information about the Milky Way’s past, present, and future.

Image description:
This image shows the Milky Way as seen by Gaia. The squares represent the location of globular clusters, the triangles the location of satellite galaxies, and the small dots are stellar streams. The dots and squares in purple are objects brought into the Milky Way by the Pontus merging galaxy.

This research by Khyati Malhan was published in The Astrophysical Journal. DOI: 10.3847/1538-4357/ac4d2a

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00:48:00

Embark on a mission with ESA astronomers Mark McCaughrean and Giovanna Giardino to learn more about the James Webb Space Telescope and the early Universe. This programme is suitable for primary and secondary students. Join the quest!

Find more educational resources, videos and links about astronomy on ESA Education’s Teach with Astronomy webpage.

Volcanoes, impact craters, tectonic faults, river channels and a lava sea: a vast amount of information is captured in a relatively small area in this geologically rich new image from ESA’s Mars Express. 

For the second time in its mission so far, the ESA/NASA Solar Orbiter spacecraft has flown through the tail of a comet. Predicted in advance by astronomers at University College London, UK, the spacecraft collected a wealth of science data that now awaits full analysis.

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Timelapse of the James Webb Space Telescope from preparation to liftoff on Ariane 5 at Europe’s Spaceport on 25 December 2021.

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Rolling stones on Mars

The NASA/ESA/CSA James Webb Space Telescope team has fully deployed the spacecraft’s sunshield in space, a key milestone in preparing it for science operations.

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Highlights of the launch campaign for the James Webb Space Telescope, from its arrival at Europe’s Spaceport in Kourou, French Guiana, weeks of launch preparations, to launch on board an Ariane 5, and separation of the spacecraft and solar panel deployment.

Now in space and on its way to L2, Webb will undergo a complex unfolding sequence. In the months after, the instruments will be turned on and their capabilities tested. After half a year in space, Webb will start its routine science observations.

Webb will see farther into our origins: from the Universe’s first galaxies, to the birth of stars and planets, to exoplanets with the potential for life, and our own Solar System.

Learn more about this historic launch

Access the related broadcast quality video material.

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Red velvet Mars

On Thursday 23 December, the James Webb Space Telescope, safely stowed inside the fairing of ESA’s Ariane 5 launch vehicle, left the final assembly building for roll-out to the launch pad at Europe’s Spaceport in French Guiana.

The ESA-Roscosmos ExoMars Trace Gas Orbiter has spotted significant amounts of water at the heart of Mars’ dramatic canyon system, Valles Marineris.

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The world’s next generation cosmic observatory, the James Webb Space Telescope, is due for launch on an Ariane 5 from Europe’s Spaceport in French Guiana.

Webb is a joint project between NASA, the European Space Agency, and the Canadian Space Agency and is a remarkable feat of engineering and technology. The telescope is fitted with the largest astronomical mirror ever flown in space, sophisticated new scientific instruments, and a sunshield the size of a tennis court.

Ariane 5 is one of the most reliable launch vehicles in the world and special modifications have been made for the preparation and launch of Webb.