Category Archives: ESA

Waiting For Gaia

Every now and then you will read my lamenting how we need better distance measurements. You might think we know the distances to distant stars, after all we reference distances. The trouble is those measures are only accurate in the broadest sense – we really do need more accuracy.

Gaia aims to change all that! ESA just posted this excellent overview of the Gaia mission.

MACS j1149.5+223

Beautiful image of a huge galaxy cluster with the name of MACS j1149.5+223. The galaxy cluster is only 5,000-million light-years away!

What’s more, this image contains a star which is “visible” because of a gravitational lens effect, it is actually much more distant. You’ll not see it in the image above but there is a link in ESA’s description below that does show it.

Before we get to the description, I was must musing about who is going to be the one(s) that come up with a way to reconstruct the lensed images? Oh it’s coming all right, has to be, we have too much great talent out there. It will be Nobel Prize time.

The original caption from ESA:

  • This image shows the huge galaxy cluster MACS J1149.5+223, whose light took over 5 billion years to reach us.The huge mass of the cluster is bending the light from more distant objects. The light from these objects has been magnified and distorted due to gravitational lensing. The same effect is creating multiple images of the same distant objects.

    Astronomers using the NASA/ESA Hubble Space Telescope have found the most distant star ever discovered. The hot blue star existed only 4.4 billion years after the Big Bang. This discovery provides new insight into the formation and evolution of stars in the early Universe, the constituents of galaxy clusters and also on the nature of dark matter.

    Go to Hubble uses cosmic lens to discover most distant star ever observed [heic1525] to learn more.

    Image: NASA, ESA, S. Rodney (John Hopkins University, USA) and the FrontierSN team; T. Treu (University of California Los Angeles, USA), P. Kelly (University of California Berkeley, USA) and the GLASS team; J. Lotz (STScI) and the Frontier Fields team; M. Postman (STScI) and the CLASH team; and Z. Levay (STScI)

The CAT in Orion

The title from ESA for this is: “THE CAT IN ORION – OR WAS IT A FOX?” I was going it’s a FOX!! Has to be.

Then I read the caption ESA included with the the image – it’s a CAT. Good eyes but we don’t know who was the first to spot the cat from the originators at ESA, Gaia or DPAC.

What’s really amazing is this is the work of Gaia.

The caption: What is the first creature that comes to mind when you look at the dark cloud in this image? Perhaps a dark kitten with a vivid white nose, front paws stretching towards the right of the frame and tail up towards the left? Or perhaps a fox, running with its mouth open and looking ahead, its vigilant eyes pointing to the right?

In fact, this animal-themed shape belongs to a dark nebula, a dense cloud of gas and dust in the constellation of Orion, the Hunter, with the cat’s nose (or fox’s eye) corresponding to the Orion Nebula Cluster, a star cluster near the famous Orion Nebula, M42. The image is based on data from the first release of ESA’s Gaia satellite, and shows the density of stars observed while scanning that region of the sky.

While this particular nebula is not visible to the naked eye, similar clouds can be seen against the bright background of the Milky Way from dark locations in the southern hemisphere. Finding shapes in these dark nebulas is part of the astronomical tradition of various cultures, from South America to Australia, that include ‘dark cloud constellations’ resembling a variety of creatures in their firmaments.

Launched in 2013, Gaia has been charting more than a billion stars to unprecedented accuracy. This information is extremely valuable to astronomers who are studying the distribution of stars across our Galaxy.

Even in the dark patches where fewer stars are observed, Gaia’s meticulous census provides important information to study the interstellar material that blocks starlight. It is in these dark clouds of gas and dust that new generations of stars come to life.

The first data release from Gaia, published in 2016, contained the position on the sky of more than a billion stars, as well as the distance and motions of about two million stars. Astronomers worldwide are now looking forward to the next data release, planned for 25 April, which will include the distance and motions for the full sample of stars, greatly extending the reach of the previous survey.

So far, Gaia data have been used to study only the most nearby regions of star formation, within several hundred light-years of us. With the new data, it will be possible to investigate in great detail regions that are much farther away, like the Orion star-forming complex, located some 1500 light-years from us, and to estimate the 3D distribution not only of stars but also of the dusty dark clouds where stars are born.

More on Gaia’s view of dark interstellar clouds

ESA’s Next Science Mission

Funny how things progress. Not that long ago other planetary systems were unknown altogether and now we know they are really common place. We’ve even gotten to the point where we going to be looking at the chemical composition of their atmospheres. That’s one of the goals of Ariel or the Atmospheric Remote‐sensing Infrared Exoplanet Large‐survey mission.

Image: (Artist’s impression): ESA/ATG medialab, CC BY-SA 3.0 IGO

ESA – 20 March 2018 The nature of planets orbiting stars in other systems will be the focus for ESA’s fourth medium-class science mission, to be launched in mid 2028.

Ariel, the Atmospheric Remote‐sensing Infrared Exoplanet Large‐survey mission, was selected by ESA today as part of its Cosmic Vision plan.

The mission addresses one of the key themes of Cosmic Vision: What are the conditions for planet formation and the emergence of life?

Thousands of exoplanets have already been discovered with a huge range of masses, sizes and orbits, but there is no apparent pattern linking these characteristics to the nature of the parent star. In particular, there is a gap in our knowledge of how the planet’s chemistry is linked to the environment where it formed, or whether the type of host star drives the physics and chemistry of the planet’s evolution.

Ariel will address fundamental questions on what exoplanets are made of and how planetary systems form and evolve by investigating the atmospheres of hundreds of planets orbiting different types of stars, enabling the diversity of properties of both individual planets as well as within populations to be assessed.

Observations of these worlds will give insights into the early stages of planetary and atmospheric formation, and their subsequent evolution, in turn contributing to put our own Solar System in context.

“Ariel is a logical next step in exoplanet science, allowing us to progress on key science questions regarding their formation and evolution, while also helping us to understand Earth’s place in the Universe,” says Günther Hasinger, ESA Director of Science.

“Ariel will allow European scientists to maintain competitiveness in this dynamic field. It will build on the experiences and knowledge gained from previous exoplanet mission
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22 Years of SOHO

Here’s to many more from SOHO.

Image: SOHO (ESA & NASA)

ESA — The activity cycle of the Sun – where the number of sunspots increase and decrease – has been monitored regularly for around 250 years, but the use of space-based telescopes has given us a whole new perspective of our nearest star.

On 22 December 2017 the Solar and Heliospheric Observatory (SOHO) reached 22 years in space. That duration is significant because it is the average length of the complete solar magnetic cycle. Sunspot cycles are known to occur over about 11 years, but the full cycle is double this length owing to the behaviour of the magnetic fields. The Sun’s polarity gradually changes through its cycle, so that after 11 years the orientation of the field will have flipped between the northern and southern hemispheres. At the end of a 22-year cycle, the orientation of the magnetic field is the same as it was at the start.

Each image shown here is a snapshot of the Sun taken every spring with the Extreme ultraviolet Imaging Telescope on SOHO. Observing in the ultraviolet reveals the Sun’s corona – the extremely hot atmosphere, up to some 2 million degrees, that extends millions of kilometres into space.

When the Sun is at its most active, strong magnetic fields show up as bright spots in the ultraviolet images of the corona. Activity also becomes obvious on the photosphere, which is the surface we see in visible light.

When the Sun is active, sunspots appear on the surface. Concentrations of magnetic fields can reduce the surface temperature in some areas and this reduced temperature makes these areas appear black in visible light images. The last 11-year cycle began in 1996, and the current one started in 2008, with solar maximum occurring in 2014.

By monitoring the Sun for almost a complete 22-year cycle, SOHO has provided a wealth of data on solar variability. This has been vital for monitoring the interaction of the Sun’s activity with Earth, and improving capabilities in space weather forecasting.

SOHO has made many important discoveries with its suite of instruments, such as revealing the existence of sunquakes, detecting waves travelling through the corona and identifying the source of the ‘fast’ solar wind.

Hypervelocity Testing

The prospect of getting hit by debris is pretty scary.

It would be great to be able to have something we could just hoover the debris – not as far fetched as it sounds.

Image: Fraunhofer Institute for High-Speed Dynamics

ESA — What looks like a mushroom cloud turned sideways is actually the instant an 2.8 mm-diameter aluminium bullet moving at 7 km/s pierces a spacecraft shield, captured by a high-speed camera.

“We used a gas gun at Germany’s Fraunhofer Institute for High-Speed Dynamics to test a novel material being considered for shielding spacecraft against space debris,” explains ESA researcher Benoit Bonvoisin.

“Our project has been looking into various kinds of ‘fibre metal laminates’ produced for us by GTM Structures, which are several thin metal layers bonded together with composite material.”

Growing levels of orbital debris pose increasing risks to all kinds of Earth-orbiting missions, adds engineer Andreas Tesch: “Such debris can be very damaging because of their high impact speeds of multiple kilometres per second.

“Larger pieces of debris can at least be tracked so that large spacecraft such as the International Space Station can move out of the way, but pieces smaller than 1 cm are hard to spot using radar – and smaller satellites have in general fewer opportunities to avoid collision.”

In some orbital regions small natural meteoroids can also pose a threat, in particular during intense seasonal meteoroid streams such as the Leonids.

To avoid damage from whatever source, protection is needed against small debris, typically consisting of one or more shields. Often used is the ‘Whipple shield’ – originally devised to guard against comet dust – with multiple layers separated by 10–30 cm.

The project, supported through ESA’s General Support Technology Programme, which prepares promising technology for spaceflight, looked at the efficiency of fibre metal laminates compared to current aluminium shields.

This still from the video shows the point after which the solid aluminium bullet has broken apart into a cloud of fragments and vapour, which becomes easier for the following layers to capture or deflect.

“The next step would be to perform in-orbit demonstration in a CubeSat, to assess the efficiency of these FMLs in the orbital environment,” concludes Benoit.

Space Radiation on Earth

So from the Van Allen Belts we turn to cosmic rays. How do we study them? ESA is up to the task.

I can’t wait until this is finished and returning data. Great stuff.

Image: GSI Helmholtzzentrum für Schwerionenforschung GmbH/Jan Michael Hosan 2018

ESA – The constant ‘rain’ of radiation in space includes cosmic rays, which, despite the name ‘ray’, comprises highly energetic particles arriving from beyond the Solar System. These rays are considered the main health hazard for astronauts conducting future exploration missions to the Moon, Mars and beyond.

This bad stuff can also play havoc with sensitive spacecraft electronics, corrupting data, damaging circuits and degrading microchips.

There are many different kinds of cosmic rays, and they can have very different effects on spacecraft and their occupants, depending on the types of particles, the particles’ energies and the duration of the exposure.

A new international accelerator, the Facility for Antiproton and Ion Research (FAIR), now under construction near Darmstadt, Germany, at the existing GSI Helmholtz Centre for Heavy Ion Research (GSI), will provide particle beams like the ones that exist in space and make them available to scientists for studies that will be used to make spacecraft more robust and help humans survive the rigours of spaceflight.

For example, researchers will be able to investigate how cells and human DNA are altered or damaged by exposure to cosmic radiation and how well microchips stand up to the extreme conditions in space.

FAIR’s central element will be a new accelerator ring with a circumference of 1100 m, capable of accelerating protons to near-light speeds. The existing GSI accelerators will repurposed to serve as pre-accelerators for the new FAIR facility.

This image shows the high-tech equipment that generates the particles, which are then injected into the GSI and FAIR accelerator systems.

On 14 February 2018, ESA and FAIR inked a cooperation agreement that will build on an existing framework of cooperation between the Agency and GSI, and see the two cooperate in the fields of radiation biology, electronic components, materials research, shielding materials and instrument calibration.

The agreement also includes cooperation in technology and software development and in joint activities in areas such as innovation management.