Cabo Verde

For World Oceans Day, the Copernicus Sentinel-3A satellite takes us over the Atlantic Ocean and the Republic of Cabo Verde.

Several of the small islands that make up the archipelago of Cabo Verde can be seen peeking out from beneath the clouds. These volcanic islands lie in the Atlantic Ocean about 570 km off the west coast of Senegal and Mauritania, which frame the image on the right.

The most striking thing about this image, however, is the dust and sand being carried by the wind towards Cabo Verde from Africa. The sand comes mainly from the Sahara and Sahel region. Owing to Cabo Verde’s position and the trade winds, these storms are not uncommon and can disrupt air traffic.

However, this sand also fertilises the ocean with nutrients and promotes the growth of phytoplankton, which are microscopic plants that sustain the marine food web. The iron in the dust is particularly important. Without iron mammals cannot make haemoglobin to transport oxygen around the bloodstream and plants cannot make chlorophyll to photosynthesise. Research has shown that around 80% of iron in samples of water taken across the North Atlantic originates from the Sahara. It can be assumed, therefore, that life in the deep ocean depends on this delivery of fertiliser from one of the world’s most parched regions.

World Oceans Day takes place on 8 June each year and celebrates the ocean, its importance in all our lives, and how we can protect it.

This image, which was captured on 30 May 2018, is also featured on the Earth from Space video programme.

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Tunguska devastation

Fallen trees at Tunguska, Imperial Russia, seen in 1929, 15 km from epicentre of aerial blast site, caused by explosion of a meteor in 1908 (Photo N. A. Setrukov, 1928).

Near-Earth objects are asteroids or comets, metres to tens of kilometres in size, that orbit the Sun and whose orbits come close to that of Earth’s. Of the more than 600 000 known asteroids in our Solar System, over 16 000 are classified as NEOs.

On 30 June 1908, above the skies of Tunguska in Russia, such an object 30–40 m in diameter and travelling at approximately 100 000 km/hour penetrated Earth's atmosphere.

It heated to approximately 10 000ºC and exploded between six and ten km above the ground. The blast released the equivalent energy of 10–15 megatons of TNT, destroying 2200 square km of forest and leaving few traces of life.

On 30 June, the United Nations observes International Asteroid Day, which aims to raise awareness about asteroids and the need to take action to protect Earth, humankind and future generations.

Near-Earth objects could potentially hit our planet and, depending on their size, produce considerable damage. While the chance of a large object hitting Earth is very small, it would produce a great deal of destruction.

ESA is in the forefront of global efforts to observe the skies and detect asteroids, share information and warnings, develop ways to deflect any that are predicted to hit us, and take action to mitigate risk and hazards when deflection is not possible.

On 30 June 2018, join ESA and the European Southern Observatory (ESO) for the live Asteroid Day webcast, packed with expert interviews, news and updates and some of the most recent asteroid science results starting at 13:00 CEST.

Click here to visit Original posting

Tunguska devastation

Fallen trees at Tunguska, Imperial Russia, seen in 1929, 15 km from epicentre of aerial blast site, caused by explosion of a meteor in 1908 (Photo N. A. Setrukov, 1928).

Near-Earth objects are asteroids or comets, metres to tens of kilometres in size, that orbit the Sun and whose orbits come close to that of Earth’s. Of the more than 600 000 known asteroids in our Solar System, over 16 000 are classified as NEOs.

On 30 June 1908, above the skies of Tunguska in Russia, such an object 30–40 m in diameter and travelling at approximately 100 000 km/hour penetrated Earth's atmosphere.

It heated to approximately 10 000ºC and exploded between six and ten km above the ground. The blast released the equivalent energy of 10–15 megatons of TNT, destroying 2200 square km of forest and leaving few traces of life.

On 30 June, the United Nations observes International Asteroid Day, which aims to raise awareness about asteroids and the need to take action to protect Earth, humankind and future generations.

Near-Earth objects could potentially hit our planet and, depending on their size, produce considerable damage. While the chance of a large object hitting Earth is very small, it would produce a great deal of destruction.

ESA is in the forefront of global efforts to observe the skies and detect asteroids, share information and warnings, develop ways to deflect any that are predicted to hit us, and take action to mitigate risk and hazards when deflection is not possible.

On 30 June 2018, join ESA and the European Southern Observatory (ESO) for the live Asteroid Day webcast, packed with expert interviews, news and updates and some of the most recent asteroid science results starting at 13:00 CEST.

Click here to visit Original posting

ESTEC’s new Galileo Payload Testbed Facility

ESA microwave engineers took apart an entire Galileo satellite to reassemble its navigation payload on a laboratory test bench to run it as though it were in orbit – available to investigate the lifetime performance of its component parts, recreate satellite anomalies, and test candidate technologies for Galileo’s future evolution.

Located in the cleanroom environment of the Galileo Payload Laboratory – part of ESA’s Microwave Lab based at its ESTEC technical centre in the Netherlands – the new Galileo IOV Testbed Facility was inaugurated this week with a ceremony attended by Paul Verhoef, ESA Director of Navigation and Franco Ongaro, ESA Director of Technology, Engineering and Quality.

Paul Verhoef congratulated the team and underlined the importance of ESA having these capabilities: ”Such a navigation payload laboratory does not exist in industry. We foresee the testing and validation a number of very innovative ideas for the next series of Galileo satellites, before entering into discussions with industry in the context of the procurement of the Galileo Transition Satellites that has recently begun. This shows the added value of ESA as the design agent and system engineer of the Galileo system.”

“Our Lab has always been very responsive to the testing needs of the Navigation Directorate,’ comments microwave engineer César Miquel España.

“Now this unique facility allows performance of end-to-end testing of a Galileo payload as representatively as possible, using actual Galileo hardware. We can also support investigations of any problems in orbit or plug in future payload hardware as needed. And because each item of equipment is separately temperature controlled we can see how environmental changes affect their performance.”

The Testbed began as an ‘engineering model’ of a first-generation Galileo In-Orbit Validation (IOV) satellite, built by Thales Alenia Space in Italy for ground-based testing. It was delivered to ESTEC in August 2015, along with four truckloads of ground support equipment and other hardware.

That began a long three-year odyssey to first take the satellite apart, then put it back together – akin at times to space archaeology, since the satellite had been designed more than 15 years ago.

“We found lots of documentation on how to integrate the satellite, but nothing on how to take it apart,” adds technician Gearóid Loughnane. “We had to dismantle it very carefully over several weeks to remove the smaller items safely and take out the electrical harness, which ended up as a big spaghetti pile on the floor.”

The next step was to extricate the navigation payload from the satellite platform, and then begin to lay it out to connect it up again. A parallel effort tracked down supporting software from the companies involved, to be able to operate the payload once it was complete, as if it is orbiting in space.

Valuable help came from Surrey Satellite Technology Limited in the UK, Dutch aerospace company Terma that developed Galileo software, and Rovsing in Denmark, supplying ground support equipment.

“A big challenge was tailoring the spacecraft control and monitoring system to work only with the payload units while having to emulate the platform equipment” comments technician Andrew Allstaff.

Comprising equipment produced by companies in seven separate European companies, the Testbed generates navigation signals using actually atomic clocks co-located in the lab, which are then upconverted, amplified and filtered as if for transmission down to Earth.

The idea came from a GIOVE Payload Testbed already in the Lab, which simulates the performance of a test satellite that prepared the way for Galileo. As a next step the team hopes they can one day produce a Galileo ‘Full Operational Capability’ Payload Testbed – the current follow-on to the first-generation IOV satellites.

The next four Galileo FOC satellites are due to be launched by Ariane 5 in July.

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ESTEC’s new Galileo Payload Testbed Facility

ESA microwave engineers took apart an entire Galileo satellite to reassemble its navigation payload on a laboratory test bench to run it as though it were in orbit – available to investigate the lifetime performance of its component parts, recreate satellite anomalies, and test candidate technologies for Galileo’s future evolution.

Located in the cleanroom environment of the Galileo Payload Laboratory – part of ESA’s Microwave Lab based at its ESTEC technical centre in the Netherlands – the new Galileo IOV Testbed Facility was inaugurated this week with a ceremony attended by Paul Verhoef, ESA Director of Navigation and Franco Ongaro, ESA Director of Technology, Engineering and Quality.

Paul Verhoef congratulated the team and underlined the importance of ESA having these capabilities: ”Such a navigation payload laboratory does not exist in industry. We foresee the testing and validation a number of very innovative ideas for the next series of Galileo satellites, before entering into discussions with industry in the context of the procurement of the Galileo Transition Satellites that has recently begun. This shows the added value of ESA as the design agent and system engineer of the Galileo system.”

“Our Lab has always been very responsive to the testing needs of the Navigation Directorate,’ comments microwave engineer César Miquel España.

“Now this unique facility allows performance of end-to-end testing of a Galileo payload as representatively as possible, using actual Galileo hardware. We can also support investigations of any problems in orbit or plug in future payload hardware as needed. And because each item of equipment is separately temperature controlled we can see how environmental changes affect their performance.”

The Testbed began as an ‘engineering model’ of a first-generation Galileo In-Orbit Validation (IOV) satellite, built by Thales Alenia Space in Italy for ground-based testing. It was delivered to ESTEC in August 2015, along with four truckloads of ground support equipment and other hardware.

That began a long three-year odyssey to first take the satellite apart, then put it back together – akin at times to space archaeology, since the satellite had been designed more than 15 years ago.

“We found lots of documentation on how to integrate the satellite, but nothing on how to take it apart,” adds technician Gearóid Loughnane. “We had to dismantle it very carefully over several weeks to remove the smaller items safely and take out the electrical harness, which ended up as a big spaghetti pile on the floor.”

The next step was to extricate the navigation payload from the satellite platform, and then begin to lay it out to connect it up again. A parallel effort tracked down supporting software from the companies involved, to be able to operate the payload once it was complete, as if it is orbiting in space.

Valuable help came from Surrey Satellite Technology Limited in the UK, Dutch aerospace company Terma that developed Galileo software, and Rovsing in Denmark, supplying ground support equipment.

“A big challenge was tailoring the spacecraft control and monitoring system to work only with the payload units while having to emulate the platform equipment” comments technician Andrew Allstaff.

Comprising equipment produced by companies in seven separate European companies, the Testbed generates navigation signals using actually atomic clocks co-located in the lab, which are then upconverted, amplified and filtered as if for transmission down to Earth.

The idea came from a GIOVE Payload Testbed already in the Lab, which simulates the performance of a test satellite that prepared the way for Galileo. As a next step the team hopes they can one day produce a Galileo ‘Full Operational Capability’ Payload Testbed – the current follow-on to the first-generation IOV satellites.

The next four Galileo FOC satellites are due to be launched by Ariane 5 in July.

Click here to visit Original posting

Horizons: Preparations to liftoff

Highlights of the preparations and liftoff for the Horizons mission with ESA astronaut Alexander Gerst.

At 11:12 GMT (13:12 CEST) on 6 June 2018, Alexander was launched into space alongside NASA astronaut Serena Auñón-Chancellor and Roscosmos commander Sergei Prokopyev in the Soyuz MS-09 spacecraft from Baikonur cosmodrome in Kazakhstan.

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Horizons: Preparations to liftoff

Highlights of the preparations and liftoff for the Horizons mission with ESA astronaut Alexander Gerst.

At 11:12 GMT (13:12 CEST) on 6 June 2018, Alexander was launched into space alongside NASA astronaut Serena Auñón-Chancellor and Roscosmos commander Sergei Prokopyev in the Soyuz MS-09 spacecraft from Baikonur cosmodrome in Kazakhstan.

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