This captivating image was taken in the north polar region of Mars by the ESA/Roscosmos ExoMars Trace Gas Orbiter’s CaSSIS camera.
Dunes come in various characteristic shapes on Mars just as on Earth, providing clues about the prevailing wind direction. Monitoring them over time also gives us a natural laboratory to study how dunes evolve, and how sediments in general are transported around the planet.
During winter in the polar regions, a thin layer of carbon dioxide ice covers the surface and then sublimates – turns directly from ice into vapour – with the first light of spring. In the dune fields, this springtime defrosting occurs from the bottom up, trapping gas between the ice and the sand. As the ice cracks, this gas is released violently and carries sand with it, forming the dark patches and streaks observed in this CaSSIS image.
The image also captures ‘barchan’ dunes – the crescent or U-shaped dunes seen in the right of the image – as they join and merge into barchanoid ridges. The curved tips of the barchan dunes point downwind. The transition from barchan to barchanoid dunes tells us that secondary winds also play a role in shaping the dune field.
The image is centred at 74.46ºN/348.3ºE. The image was taken on 25 May 2019.
New images and results from the ESA/Roscosmos ExoMars Trace Gas Orbiter’s suite of scientific instruments will be discussed this week at the joint meeting of the European Planetary Science Congress and the Division of Planetary Sciences in Geneva, Switzerland, this week. Follow the conversation on Twitter via #EPSCDPS2019.
The Copernicus Sentinel-2 mission takes us over Clarence Strait, a narrow body of water in Australia’s Northern Territory.
Click on the box in the lower-right corner to view this image at its full 10 m resolution directly in your browser.
The strait ties the Beagle Gulf in the west with the Van Diemen Gulf to the east and separates Australia’s mainland from Melville Island, part of the Tiwi Islands. The southernmost tip of Melville is visible in the upper part of the image.
The three islands in the southern part of the strait, are the Vernon Islands, which host navigation aids to assist vessels passing through the strait.
Australia’s Northern Territory is a sparsely-populated region. With a population of around 140 000, Darwin is the territory’s capital and largest city, and is visible in grey in the centre of the image.
In 1839, the HMS Beagle sailed into the waters of what is now known as Darwin Harbour. The harbour was named after the British evolutionist Charles Darwin, but, contrary to popular belief, Darwin himself never visited the area.
With a strong Aboriginal culture, art and tropical summers, Darwin is a popular tourist destination. The Crocosaurus Cove in the heart of the city houses the world’s largest display of Australian reptiles.
The waters that surround Darwin are riddled with saltwater crocodiles and deadly box jellyfish, which inhabit the waters from October to May. The Adelaide River, known for its high concentration of saltwater crocodiles, can be seen to the right of Darwin, snaking its way northwards, flowing 180 km before emptying into the Timor Sea.
The Djukbinj National Park, visible east of Adelaide River, is a protected area and consists mostly of wetlands. The close vicinity to the water makes the park a major breeding ground for a variety of water birds, including magpie geese, herons and egrets.
Copernicus Sentinel-2 is a two-satellite mission. Each satellite carries a high-resolution camera that images Earth’s surface in 13 spectral bands. Data from Copernicus Sentinel-2 can help monitor changes in land cover.
This image, captured on 24 June 2019, is also featured on the Earth from Space video programme.
Astronauts from five space agencies around the world take part in ESA’s CAVES training course– Cooperative Adventure for Valuing and Exercising human behaviour and performance Skills.
The six cavenauts of this edition of CAVES are ESA astronaut Alexander Gerst, NASA astronauts Joe Acaba and Jeanette Epps, Roscosmos’ cosmonaut Nikolai Chub, Canadian Space Agency astronaut Josh Kutryk and Japan’s space agency Takuya Onishi.
The three-week course prepares astronauts to work safely and effectively in multicultural teams in an environment where safety is critical.
As they explore caves they encounter caverns, underground lakes and strange microscopic life. They test new technology and conduct science – just as if they were living on the International Space Station.
The six astronauts have to rely on their own skills, teamwork and ground control to achieve their mission goals – the course is designed to foster effective communication, decision-making, problem-solving, leadership and team dynamics.
The structural and thermal model of the Euclid satellite recently completed its thermal qualification tests at Thales Alenia Space’s premises in Cannes, France. Integrated in near-flight configuration, including the payload and service modules, the satellite model is ready to undergo mechanical vibration tests in coming weeks.
Euclid is a medium-class mission in ESA's Cosmic Vision programme to investigate the expansion of our Universe over the past ten billion years, probing cosmic epochs from before the expansion started to accelerate, all the way to the present. To this aim, the mission will survey galaxies at a variety of distances from Earth, using a 1.2 m diameter telescope with two instruments – the visual imager (VIS) and the near-infrared spectrometer and photometer (NISP) – and covering an area of the sky equivalent to more than 35 percent of the celestial sphere.
By making use of both weak gravitational lensing, which measures the distortion of distant galaxies caused by intervening matter, and baryonic acoustic oscillations, based on measurements of the clustering of galaxies, Euclid will capture a 3D picture of the evolving distribution of both dark and ordinary (or baryonic) matter in the cosmos. This will enable scientists to reconstruct the past few billion years of the Universe's expansion history, estimating the acceleration caused by the mysterious dark energy to percent-level accuracy, and possible variations in the acceleration to 10 percent accuracy.
The satellite model shown in this photo is not the so-called flight model – the one that will be eventually launched – but it contains flight-worthy spare parts. From a mechanical point of view, it is identical to the flight model, and it allows engineers to apply extreme thermal and mechanical stresses during testing, without having to subject the delicate flight hardware to same processes. These tests, which will soon involve vibrations using a large shaker to simulate launch conditions, are performed to determine whether the thermal and mechanical properties of the actual hardware correspond to the predictions.
In order to reach Euclid’s ambitious science goals, the main design drivers include the quality and stability of the integrated optical system; the speed and completeness of its sky survey capability; accurate and stable pointing; and the ability to reliably transmit to the ground the huge volumes of scientific data that the satellite will gather. The design proposed by Thales Alenia Space, the mission’s prime contractor, is based on the experience gained with ESA’s Herschel and Planck missions, which both demonstrated excellent performance in orbit and delivered extraordinary data to delve into the mysteries of our Universe.
In addition to that, a peculiarity of Euclid is that the satellite will maintain a very stable optical performance under the most extreme attitude changes that will occur during slew manoeuvres. The recent thermal vacuum tests have simulated and successfully proven the capability to maintain the thermal stability in these conditions. The next step will be to confirm that also the optical stability will be ensured, but this will only happen during the end-to-end test of the payload module flight model next year.
Meanwhile, integration and testing of the flight model of the Euclid telescope and service module have already started at the premises of Airbus in Toulouse, France and Thales Alenia Space in Turin, Italy, respectively. The two modules will be integrated in 2021, and the complete satellite will undergo final tests in preparation to launch, which is scheduled for 2022.
ESA astronaut Luca Parmitano shares a light dinner with his Expedition 60 crewmates on the International Space Station.
Luca posted this image to social media during his Beyond mission with the caption: Among friends for a light dinner… so light that everything flies.
Throughout human history, spectacular auroral eruptions have given rise to fearful beliefs of mythological creatures, have driven folklore and have influenced culture, religion and art.
Today, we know the aurora are the visible manifestations in our atmosphere of space weather, and occur when electrically charged particles from the Sun collide with Earth’s atmosphere. These particles are delivered by the ‘solar wind’ — a constant stream of electrons, protons and heavier ions — emitted by our Sun.
At the remote Concordia research station in Antarctica, a beautiful and harmless display of Aurora Australis or Southern Lights caught ESA-sponsored medical doctor Nadja Albertsen by surprise.
“I turn my gaze away from the horizon and dusk, there is a stripe in the sky that is not the Milky Way, at first just white and cloud-like, but there is no doubt – the green hues are visible and the curtain-like waves in the sky are unmistakable,” as she explains in her latest Concordia blog post.
Concordia is run by the French and Italian polar organisations to collect data for subjects as diverse as glaciology, astronomy and climate science.
For a whole year, Nadja facilitates a number of experiments on the effects of isolation, light deprivation, and extreme temperatures on the human body and mind.
“The aurora is an amazing experience and one that I don’t think anyone gets tired of – even if you live a lifetime with it as a frequent guest,” she adds.
But beauty often comes at a price, and the cost of the aurora, popularly known as the Northern or Southern Lights depending on the hemisphere, is constant surveillance of the Sun. Aurora remind us that we live with an active star that can do real damage to daily life.
The giver of light and heat and a key enabler of life on our planet, our Sun is also a volatile ball of hot gas 1.3 million times larger than Earth. Unpredictable and temperamental, our Sun blasts intense radiation and colossal amounts of energetic material in every direction, creating the ever-changing conditions in space known as ‘space weather’.
Aurora offer a visual means to study space weather. We cannot control our Sun, but timely alerts – like those to be enabled by ESA’s future Lagrange solar warning mission – will allow civil authorities and commercial actors to take protective measures, helping minimise economic losses and avoid a disaster that could affect all of us.
Follow Nadja’s adventures at Concordia on the blog.
This rugged control panel has been designed to be used by a cosmonaut in a spacesuit, on the outside of the International Space Station.
Known as the ‘External Man Machine Interface’, it will be used to control the European Robotic Arm, which is due to reach the Station as part of Russia’s long-awaited Nauka (meaning ‘Science’) Multipurpose Laboratory Module (MLM) next year.
ESA designed the European Robotic Arm (ERA) as part of its contributions to the ISS. The 11.3-m long, seven degrees of freedom robotic manipulator will be the third arm to reach the Station, following Canada’s ‘Canadarm’ and Japan’s Remote Manipulator System. Serving the Russian segment of ISS, ERA will be able to manipulate payloads of up to 8 tonnes, with a positioning accuracy of 5 mm.
“The Russians wanted to give their spacewalkers the option of direct control over ERA,” explains ESA robotics engineer Lodewijk Aris.
“So we built this external interface along with as a pair of internal interfaces. External control is one of the attributes that make ERA unique among the Station arms. The interface is designed to endure the space environment for at least a decade – when not in use the hinged cover is closed, to protect it from thermal extremes, radiation and micrometeorites.
“This is a qualification model – its flight model is with Russia’s Energia company along with ERA itself. The qualification model of ERA is also here in ESTEC, which we will be using for tests and anomaly investigations post-launch.
“We’ll be demonstrating part of this ERA ‘Iron Bird’ during the ESA Open Day on Sunday 6 October. The whole arm is too bulky for our facilities, but we’ll be controlling its wrist live during the Open Day, using the laptop-style internal interface.”
Able to move in a similar manner to a human arm, ERA is symmetrical in design around its central elbow joint, with both ends of the arm concluding in end effectors that can function together with their wrists either as ‘shoulders’ or ‘hands’.
Its shoulder side will be connected to one of four different ‘base plates’ around the MLM, providing data and power links, while its wrist-and-hand side will be able to take payloads from the module’s airlock and place them on a selection of payload mounting units. ERA will be relocated between base plates as required.
ERA’s end effectors also feature cameras for visual inspection and screwdriver-like ‘integrated service tool’ for securing payloads using a standardised pin latch attachment system. The combination of a laser-based lighting unit and force sensor will allow precise manipulation of payloads, including installing and removing them.
As a safety feature, ERA includes a detailed virtual map of the ISS to prevent any accidental collision with Station structure – which has been kept updated as the Station grew during its wait for flight.
“The MLM, equipped with its own solar panels, an airlock and Soyuz docking port as well as ERA should offer a significant boost to ISS science,” adds Aris. “Directly after its in-orbit validation phase, ERA will have the crucial role of installing the MLM’s radiator and airlock – with backup from the ERA operations room here in the ESTEC technical centre in the Netherlands – before being formally handed over to the Russians for operational use.”
The launch of the 20-tonne MLM by Proton rocket is currently planned from Kazakhstan’s Baikonour cosmodrome in December 2020.
ESA astronaut Luca Parmitano captured this image of the United Arab Emirates from the International Space Station and shared it on his social media channels saying: "Natural and artificial structures alternate on the Emirates coast, creating complex water currents."
Luca was launched to the International Space Station for his second mission, Beyond, on 20 July 2019. He will spend six months living and working on the orbital outpost where he will support more than 50 European experiments and more than 200 international experiments in space.
This image from ESA’s Mars Express shows a beautiful slice of the Red Planet from the northern polar cap downwards, and highlights cratered, pockmarked swathes of the Terra Sabaea and Arabia Terra regions. It comprises data gathered on 17 June 2019 during orbit 19550.
The ground resolution at the centre of the image is approximately 1 km/pixel and the images are centred at about 44°E/26°N. This image was created using data from the nadir and colour channels of the High Resolution Stereo Camera. The nadir channel is aligned perpendicular to the surface of Mars, as if looking straight down at the surface. North is up.
Many of the best-loved galaxies in the cosmos are remarkably large, close, massive, bright, or beautiful, often with an unusual or intriguing structure or history. However, it takes all kinds to make a Universe — as demonstrated by this Hubble Picture of the Week of Messier 110.
Messier 110 may not look like much, but it is a fascinating near neighbour of our home galaxy, and an unusual example of its type. It is a member of the Local Group, a gathering of galaxies comprising the Milky Way and a number of the galaxies closest to it. Specifically, Messier 110 is one of the many satellite galaxies encircling the Andromeda Galaxy, the nearest major galaxy to our own, and is classified as a dwarf elliptical galaxy, meaning that it has a smooth and almost featureless structure. Elliptical galaxies lack arms and notable pockets of star formation — both characteristic features of spiral galaxies. Dwarf ellipticals are quite common in groups and clusters of galaxies, and are often satellites of larger galaxies.
Because they lack stellar nurseries and contain mostly old stars, elliptical galaxies are often considered ‘dead’ when compared to their spiral relatives. However, astronomers have spotted signs of a population of young, blue stars at the centre of Messier 110 — hinting that it may not be so dead after all.
Week in images
16 - 20 September 2019