This is the most powerful sound system in Europe – but no human being could survive hearing it at maximum output.
Engineer Kees van Zijtveldt is standing beside the largest sound horn of ESA’s Large European Acoustic Facility (LEAF), capable of subjecting satellites to the same noise a launcher produces as it takes off and flies through the atmosphere.
LEAF is an integral part of ESA’s ESTEC Test Centre in Noordwijk, the Netherlands, a collection of spaceflight simulation facilities under a single roof. One wall of the chamber – which stands 11 m wide by 9 m deep and 16.4 m high – is embedded with a set of enormous sound horns. Nitrogen shot through the horns can produce a range of noise up to more than 154 decibels, like standing close to multiple jets taking off.
As a safety feature, LEAF can operate only once all the doors are closed. Steel-reinforced concrete walls safely contain its noise, coated with epoxy resin to reflect noise to produce a uniform sound field within the chamber. The chamber itself is supported on rubber bearing pads to isolate it from its surroundings.
The Whirlpool Galaxy, also known as M51 or NGC 5194, is one of the most spectacular examples of a spiral galaxy. With two spiral arms curling into one another in a billowing swirl, this galaxy hosts over a hundred billion stars and is currently merging with its companion, the smaller galaxy NGC 5195.
Around 30 million light-years away, the Whirlpool Galaxy is close enough to be easily spotted even with binoculars. Using the best telescopes available both on the ground and in space, astronomers can scrutinise its population of stars in extraordinary detail.
In this image, observations performed at three different wavelengths with ESA’s Herschel and XMM-Newton space telescopes are combined to reveal how three generations of stars coexist in the Whirlpool Galaxy.
The infrared light collected by Herschel – shown in red and yellow – reveals the glow of cosmic dust, which is a minor but crucial ingredient in the interstellar material in the galaxy’s spiral arms. This mixture of gas and dust provides the raw material from which the Whirlpool Galaxy’s future generations of stars will take shape.
Observing in visible and ultraviolet light, astronomers can see the current population of stars in the Whirlpool Galaxy, since stars in their prime shine most brightly at shorter wavelengths than infrared. Seen at ultraviolet wavelengths with XMM-Newton and portrayed in green in this composite image are the galaxy’s fiercest stellar inhabitants: young and massive stars pouring powerful winds and radiation into their surroundings.
The image also shows the remains of previous stellar generations, which shine brightly in X-rays and were detected by XMM-Newton. Shown in blue, these sources of X-rays are either the sites where massive stars exploded as supernovae in the past several thousand years, or binary systems that host neutron stars or black holes, the compact objects left behind by supernovae.
ESA astronaut Alexander Gerst taken by his crewmate NASA astronaut Reid Wiseman as they train for their six-month mission to the International Space Station starting in May.
Reid Tweeted this message with the image: “Lucky photo! Helps when your subject is photogenic and his country’s flag is behind him.”
Alexander and Reid spend many hours training with spacesuits in swimming pools to recreate the feeling of weightlessness in orbit. The Space Station offers two types of spacesuits for working outside of the space laboratory – the Russian Orlan and the American spacesuit that Alex is wearing here.
Called the Extravehicular Mobility Unit, or EMU, the NASA spacesuit is nothing less than a miniature spacecraft that supplies oxygen and keeps astronauts at the right temperature. The suit provides protection against the vacuum of space and temperature differences of over 200°C as the Space Station passes from sunlight into the shadow of Earth 16 times each day.
Alexander is flight engineer for Expedition 40/41, which will be launched to the Station in May 2014 on a long-duration mission to run science experiments and maintain humankind’s space base.
This image from Envisat’s radar shows the Zambezi River’s floodplain in western Zambia.
The city of Mongu appears as a cluster of white radar reflections on the right side of the image. It is about 15 km from the river’s main channel – which appears light green, snaking down the left side of the image – but during the wet season, the waters rise right up to the edge of the town.
This image is a compilation of three acquisitions from Envisat’s radar. Each acquisition is assigned a colour, and when combined show changes between the acquisitions.
The individual images were acquired on 1 March, during the wet season, 27 September and 26 December, when water levels were low, all during 2011. Combined, the psychedelic array of colours reveal how drastically the floodplain changes between seasons.
As the second largest wetland in Zambia, the Zambezi floodplain is a major spawning ground for fish. With about 80 different fish species, it serves as a source of livelihood to the local people, along with harvesting of other wetland resources like reeds and sedges for handicraft, and rice cultivation.
But this area is threatened by unsustainable fishing, animal poaching and the dredging of canals.
The Zambezi floodplains is just one of the over 2000 sites worldwide considered to be wetlands of international importance by the Ramsar Convention – an intergovernmental treaty for the sustainable use of wetlands. World Wetlands Day is observed on 2 February, the anniversary of the signing of the Convention.
ESA assists the Ramsar Convention through the GlobWetland project and the TIGER initiative ‘Looking After Water in Africa’, which provide satellite data to be used to monitor these precious resources.
This image is featured in the Earth from Space video programme.
Tianjin, China, lies around 100 km southeast of Beijing near China’s eastern coast. At the top right of this image – taken from the International Space Station at night – is the Tianjin Port welcoming ships from the Bohai Bay.
The street lighting in Tianjin is interesting as it shows two different colours, presumably from different lighting technologies. At night the dual urban areas of Tianjin show up clearly with the centre and old city in the middle and the newer urban city of Binhai to the right along with the port.
The other two lit-up areas in this image are the cities of Wuqing on the road to Beijing heading North (to the left here) and Jinnan below Binhai.
Tianjin is the fourth largest city of China with over 12 million inhabitants. This image was taken by an astronaut from the International Space Station using Nightpod: ESA’s camera aid that tracks the motion of Earth as our planet flies underneath the orbital outpost at 28 800 km/h. The resulting images are sharper than if an astronaut compensates for the Earth’s rotation by hand.
Testing the deployment of the Sentinel-1A radar antenna in the cleanroom at Thales Alenia Space in Cannes, France, on 21 January 2014. As the satellite is designed to operate in orbit, it is hung from a structure during tests to simulate weightlessness.
The Synthetic Aperture Radar, or SAR, will provide an all-weather day-and-night supply of imagery for services such as the monitoring of Arctic sea-ice extent, routine sea-ice mapping, surveillance of the marine environment, monitoring land-surface for motion risks and mapping to support humanitarian aid and crisis situations.
Sentinel-1A – the first satellite built for the Copernicus environmental monitoring programme – is foreseen for launch in the spring of 2014 from Europe’s spaceport in Kourou, French Guiana.
Everybody is waiting for what Rosetta will do next. The Rosetta Engineering Qualification Model, kept in a cleanroom at ESOC, still helps engineers and scientists makes plans for the spacecraft that left Earth almost a decade ago.
ESA astronaut Timothy Peake (centre) takes part in winter survival training near Star City outside Moscow, Russia. Survival training is an important part of all Soyuz mission training. There is always the possibility that a Soyuz spacecraft could land in a remote, cold area. All astronauts have to learn to survive in harsh climates while waiting for rescue.
ESA astronaut Andreas Mogensen (left) takes part in winter survival training near Star City outside Moscow, Russia. Survival training is an important part of all Soyuz mission training. There is always the possibility that a Soyuz spacecraft could land in a remote, cold area. All astronauts have to learn to survive in harsh climates while waiting for rescue.
A piece of art? A time-lapse photo? A flickering light show?
At first glance, this image looks nothing like the images that we are used to seeing from Hubble.
The distinctive splashes of colour must surely be a piece of modern art, or an example of the photographic technique of "light painting". Or, could they be the trademark tracks of electrically charged particles in a bubble chamber? On a space theme, how about a time-lapse of the paths of orbiting satellites?
The answer? None of the above. In fact, this is a genuine frame that Hubble relayed back from an observing session.
Hubble uses a Fine Guidance System (FGS) in order to maintain stability whilst performing observations. A set of gyroscopes measures the attitude of the telescope, which is then corrected by a set of reaction wheels. In order to compensate for gyroscopic drift, the FGS locks onto a fixed point in space, which is referred to as a guide star.
It is suspected that in this case, Hubble had locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in this remarkable picture of brightly coloured stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288. It seems that even when Hubble makes a mistake, it can still kick-start our imagination.
A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Judy Schmidt.
Week in Images
27-31 January 2014