Inseparable Galactic Twins

ESA - Hubble Space Telescope patch.

July 2, 2013

Image above: The galaxy pair MRK 1034. Image Credit: ESA/Hubble and NASA (acknowledgement, Judy Schmidt).

Looking towards the constellation of Triangulum (The Triangle), in the northern sky, lies the galaxy pair MRK 1034. The two very similar galaxies, named PGC 9074 and PGC 9071, are close enough to one another to be bound together by gravity, although no gravitational disturbance can yet be seen in the image. These objects are probably only just beginning to interact gravitationally.

Both are spiral galaxies, and are presented to our eyes face-on, so we are able to appreciate their distinctive shapes. On the left of the image, spiral galaxy PGC 9074 shows a bright bulge and two spiral arms tightly wound around the nucleus, features which have led scientists to classify it as a type Sa galaxy. Close by, PGC 9071 — a type Sb galaxy — although very similar and almost the same size as its neighbor, has a fainter bulge and a slightly different structure to its arms: their coils are further apart.

The spiral arms of both objects clearly show dark patches of dust obscuring the light of the stars lying behind, mixed with bright blue clusters of hot, recently-formed stars. Older, cooler stars can be found in the glowing, compact yellowish bulge towards the center of the galaxy. The whole structure of each galaxy is surrounded by a much fainter round halo of old stars, some residing in globular clusters.

Gradually, these two neighbors will attract each other, the process of star formation will be increased and tidal forces will throw out long tails of stars and gas. Eventually, after maybe hundreds of millions of years, the structures of the interacting galaxies will merge together into a new, larger galaxy.

The images combined to create this picture were captured by Hubble's Advanced Camera for Surveys.

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

For more information about NASA / ESA Hubble Space Telescope: http://www.nasa.gov/hubble and http://www.spacetelescope.org/

Image (mentioned), Text, Credits: ESA / NASA.

Cheers, Orbiter.ch

Cluster discovers steady leak in Earth's plasmasphere‏

ESA - Cluster II Mission patch.

02 July 2013

A steady wind, discovered by ESA's Cluster mission, is slowly escaping from Earth's plasmasphere - the torus of plasma that surrounds our planet's atmosphere. The outflow amounts to almost 90 tonnes a day. Predicted by theory two decades ago, this is one of the main mechanisms that replenishes Earth's magnetosphere with fresh plasma.

The environment that surrounds Earth, beyond the outermost layers of the atmosphere, is strongly shaped by the magnetic field of our planet. There, space is filled with electrons and positive ions, which move along the magnetic field lines. The interaction between Earth's magnetic field and the solar wind produces the complex topography of the magnetosphere.

The innermost part of the magnetosphere is a doughnut-shaped region called the plasmasphere, which is centred around the Earth's equator and rotates along with it. This plasmasphere, whose toroidal shape is forged by the magnetic field of Earth, exchanges mass and energy with the outer layers of the magnetosphere, and scientists have been studying the details of the interaction between these two regions.

Animation of the plasmaspheric wind. Credit: ESA/ATG medialab

"We have long known that the plasmasphere supplies material to the outer magnetosphere," explains Iannis Dandouras from the Institut de Recherche en Astrophysique et Planétologie (a joint CNRS and Université Paul Sabatier institute) in Toulouse, France.

"However, up until now we could only see this happening during sporadic, localised and powerful events that we call plumes."

Analysing data from ESA's Cluster mission, Dandouras has discovered another source of the supply: a steady wind that continuously transfers material from the plasmasphere into the magnetosphere. The results of his study are published in Annales Geophysicae.

"Now we have finally found proof of a permanent and continuous leakage of material from the plasmasphere outwards," he says.

"It is something similar to what happens also around the Sun, when the solar corona expands outwards at equatorial latitudes and gives rise to the solar wind."

Earth's magnetosphere. Credit: ESA/ATG medialab

Scientists had suspected that such a plasmaspheric wind must exist ever since the first observations of plume events in the early 1990s. Plumes are dense columns of plasma that form in the plasmasphere when it is hit by a geomagnetic storm – a disturbance in Earth's magnetic environment caused by sudden changes in the solar wind. After they form, plumes expand outwards and eventually burst, releasing large amounts of fresh plasma in the outer layers of the magnetosphere.

"When a plume strikes out, it partially drains the plasmasphere, which is then replenished with plasma coming from Earth's ionosphere, the top layer of the atmosphere," explains Dandouras.

Early studies of plumes monitored how long it took to refill the plasmasphere after such an event.

"Surprisingly, this process took much longer than expected, like trying to fill up a leaky container."

In 1992 two scientists approached the problem from a theoretical point of view. When Joseph Lemaire, from the Belgian Institute for Space Aeronomy in Brussels, Belgium, was visiting Robert Schunk at Utah State University, USA, they tried to simulate this puzzling finding by investigating the interplay of forces in the plasmasphere. Their study revealed a net imbalance between three players: the gravitational attraction due to Earth's mass, the centrifugal force caused by its rotation and the pressure exerted by the plasma. As a result of the imbalance, an instability develops, driving the plasma outwards.

The plasmasphere in Earth's magnetosphere. Credit: ESA/ATG medialab

The instability predicted by the work of Lemaire and Schunk is continuous rather than episodic, and takes the form of a wind of plasma. The wind is continuously flowing radially out of the doughnut-shaped plasmasphere and into the surrounding layers of the magnetosphere.

It was Lemaire who first introduced Dandouras to this particular problem.

"We were chatting about the plasmasphere at a workshop a few years ago, when Joseph Lemaire mentioned his and Schunk's prediction of this wind," remembers Dandouras.

"Quite some time had passed after their work had been published, yet only indirect evidence was found to support their prediction. As an experimental space scientist, this triggered my curiosity immediately.

"The Cluster mission was already operating and collecting data at the time, and we both agreed that the Cluster Ion Spectrometry experiment (CIS) would be the perfect tool to verify directly whether the plasmasphere is actually leaking."

The plasmaspheric wind is expected to be blowing at all times, regardless of the activity of the magnetosphere; in contrast, plumes only arise when Earth's magnetic environment is highly active. So Dandouras dug into the Cluster archive looking for data that had been gathered during quiet magnetospheric times.

"The inquiry was a very delicate process: if at all present, this wind would be very weak, and it would be really challenging to single it out from the overall distribution of the low-energy ions that make up the plasmasphere," says Dandouras.

But the high sensitivity of the CIS experiment proved crucial to the study, along with a specially developed filtering technique.

The plasmaspheric wind. Credit: ESA/ATG medialab

"After long scrutiny of the data, there it was, a slow but steady wind, releasing about 1 kg of plasma every second into the outer magnetosphere: this corresponds to almost 90 tonnes every day. It was definitely one of the nicest surprises I've ever had!"

At this rate, the mass loss is a negligible contribution to the depletion of Earth's atmosphere, whose mass amounts to over 1018 kg. However, this constant outflow plays a significant role in the supply of plasma to the outer magnetosphere, surpassed in efficiency only by the solar wind, which is also a steady source, and by the occasional and powerful plumes.

"This discovery confirms that Earth's ionosphere and plasmasphere feed the magnetosphere on a regular basis, and not only during active periods," comments Philippe Escoubet, Cluster Project Scientist at ESA. "This allows us to study Earth's atmospheric loss in great detail and to compare it with similar phenomena that occur on other planets in the Solar System at different rates, depending on the intensity of each planet's magnetic field."

Notes for editors:

The study presented here is based on data gathered with the Cluster Ion Spectrometry (CIS) experiment on board the Cluster spacecraft on three occasions in 2001, on two occasions in 2002 and once in 2006.

Cluster is a constellation of four spacecraft flying in formation around Earth. It is the first space mission able to study, in three dimensions, the natural physical processes occurring within and in the near vicinity of the Earth's magnetosphere. Launched in 2000, it is composed of four identical spacecraft orbiting the Earth in a pyramidal configuration, along a nominal polar orbit of 4 × 19.6 Earth radii (1 Earth radius = 6380 km). Cluster's payload consists of state-of-the-art plasma instrumentation to measure electric and magnetic fields over wide frequency ranges, and key physical parameters characterising electrons and ions from energies of near 0 eV to a few MeV. The science operations are coordinated by the Joint Science Operations Centre (JSOC) at the Rutherford Appleton Laboratory, United Kingdom, and implemented by ESA's European Space Operations Centre (ESOC), in Darmstadt, Germany.

Related publications:

I. Dandouras, "Detection of a plasmaspheric wind in the Earth's magnetosphere by the Cluster spacecraft", 2013, Annales Geophysicae, 31, 1143-1153, doi:10.5194/angeo-31-1143-2013:
http://sci.esa.int/cluster/object/index.cfm?fobjectid=51993

J. F. Lemaire & R. W. Schunk, "Plasmaspheric wind", 1992, Journal of Atmospheric and Terrestrial Physics, vol. 54, p. 467-477: http://sci.esa.int/cluster/object/index.cfm?fobjectid=51980

Related links:
Space Weather: http://sci.esa.int/cluster/object/index.cfm?fobjectid=33273

Cluster Mission Home: http://sci.esa.int/cluster

Images, Video, Text, Credits: ESA / ATG medialab.

Greetings, Orbiter.ch

Launch of Indian PSLV C22 Rocket with IRNSS-1 satellite

ISRO - Indian Space Research Organization logo.


July 2, 2013

 Launch of Indian PSLV C22 Rocket with IRNSS-1

An Indian Polar Satellite Launch Vehicle (PSLV) succesfully launched from India today, July 1st 2013 at 18:11 UTC carrying the first of seven IRNSS satellites into orbit. Indian Regional Navigation Satellite System (IRNSS) will provide real time navigation and time data to multiple users.

Indian Regional Navigation Satellite System (IRNSS) description. Image credit: thehindu.com

This was the very first night launch of the Indian Polar Satellite Launch Vehicle which uses four stages.

Image above: India has successfully put the country’s first Navigation Satellite into orbit on Monday. A Polar Satellite Launch Vehicle blasted off from the Satish Dhawan Space Center on India’s East coast at 18:11 UTC and made a flawless ascent mission delivering the IRNSS-1A spacecraft to its intended orbit about 20 minutes after launch. The flight was declared a complete success – marking the birth of India’s own navigation constellation, the Indian Regional Navigation System that will cover the country and surrounding areas. Credit ISRO.

Image above: LIFTOFF of an Indian PSLV from Satish Dhawan carrying India’s first navigation satellite. India’s first navigation satellite has arrived in orbit. Photo Screen Capture from ISRO TV.

 Indian Regional Navigation Satellite System (IRNSS). Credit: ISRO

 For more information about Indian Space Research Organization (ISRO), visit: http://www.isro.org/

Images (mentioned), Video, Text, Credits: ISRO / ISRO TV.

Best regards, Orbiter.ch

CryoSat maps largest-ever flood beneath Antarctica

ESA - CryoSat 2 Mission logo.

2 July 2013

ESA’s CryoSat satellite has found a vast crater in Antarctica’s icy surface. Scientists believe the crater was left behind when a lake lying under about 3 km of ice suddenly drained.

Far below the thick ice sheet that covers Antarctica, there are lakes of fresh water without a direct connection to the ocean. These lakes are of great interest to scientists who are trying to understand water transport and ice dynamics beneath the frozen Antarctic surface – but this information is not easy to obtain.

Site of crater

One method is to drill holes through kilometres of ice to the water – a difficult endeavour in the harsh conditions of the polar regions.

But instead of looking down towards the ice, a team of European scientists is looking to the sky to improve our understanding of subglacial water and its transport.

By combining new measurements acquired by CryoSat with older data from NASA’s ICESat satellite, the team has mapped the large crater left behind by a lake, and even determined the scale of the flood that formed it.

From 2007 to 2008, six cubic kilometres of water – about the same amount that is stored in Scotland’s Loch Ness – drained from the lake, making it the largest event of its kind ever recorded.

3D view

That amount of water equals a tenth of the melting that occurs beneath Antarctica each year.

Since the end of 2008, the lake appears to be refilling but six times slower than it drained. It could take decades to reform.

The study, published recently in Geophysical Research Letters, highlights CryoSat’s unique capacity to map changes in Antarctica’s subglacial lakes in 3D, and sheds new light on events at the base of the ice sheet.

CryoSat carries a radar altimeter that can ‘see’ through clouds and in the dark, providing continuous measurements over areas like Antarctica that are prone to bad weather and long periods of darkness.

The radar can measure both the area and depth of ice craters in high resolution, allowing scientists to calculate its volume accurately.

ESA's ice mission CryoSat

“Thanks to CryoSat, we can now see fine details that were not apparent in older satellite data records,” said Dr Malcolm McMillan from the UK’s University of Leeds and lead author of the study ‘Three-dimensional mapping by CryoSat-2 of subglacial lake volume changes’.

With every subglacial lake, there is hope of finding prehistoric marine life. The rapid draining and apparent refilling of this lake, however, suggests this was not the first time water has drained from the lake.

“It seems likely that the flood water – and any microbes or sediments it contained – has been flushed into the Southern Ocean, making it difficult to imagine that life in this particular lake has evolved in isolation,” said Prof. Andrew Shepherd, a co-author of the study.

About 400 lakes have been discovered at the base of the Antarctic ice sheet. When they drain, they disrupt subglacial habitats and can cause the ice above to slide more quickly into the sea.

Related links:

‘Three-dimensional mapping by CryoSat-2 of subglacial lake volume changes’: http://onlinelibrary.wiley.com/doi/10.1002/grl.50689/pdf

Geophysical Research Letters: http://www.agu.org/journals/gl/

University of Leeds: http://www.leeds.ac.uk/

British Antarctic Survey: http://www.antarctica.ac.uk/

University College London: http://www.ucl.ac.uk/

ICESat mission: http://icesat.gsfc.nasa.gov/

CryoSat - An Earth Explorer: http://www.esa.int/Our_Activities/Observing_the_Earth/CryoSat/An_Earth_Explorer
   
CryoSat: an icy mission: http://www.esa.int/Our_Activities/Observing_the_Earth/CryoSat/CryoSat_an_icy_mission

Images, Text, Credits: ESA / M. McMillan / AOES Medialab.

Cheers, Orbiter.ch

The Proton-M rocket with three Glonass satellites crashed after takeoff

Russian Navigation Satellites Glonass patch.

July 2, 2013

A Russian Proton-M rocket carrying three GLONASS navigation satellites crashed soon after takeoff from Kazakhstan’s Baikonur cosmodrome.

Proton-M with three Glonass satellites liftoff and crash

Immediately after takeoff, the rocket swerved to one side, tried to correct itself, but instead veered in the opposite direction. It then flew horizontally and started to come apart with its engines in full thrust.

Making a huge arch in the air, the rocket plummeted back to earth and exploded on impact close to another launch pad used for Proton commercial launches.

The crash was broadcast live across the country and fears of a possible toxic fuel leak immediately surfaced following the incident. While no such leak has been confirmed, the rocket was initially carrying over 600 tons of toxic propellants.

There have reportedly been no casualties to surroundings structures and the town of Baikonur was not affected. Taking into account the Proton-M rocket and three GLONASS satellites, the failed launch has potentially cost the Russian space industry around $200 million, reported Rossiya24 TV channel.

An accident board headed by Aleksandr Lopatin, deputy head of Russia’s space agency Roskosmos, has been created to investigate the crash.

The emergency ministry of Kazakhstan has warned that toxic fuel from the rocket could pose an ecological threat to the surrounding area.

A cloud of toxic smoke emanating from the burning fuel has led to the evacuation of the area in the immediate vicinity to the crash site.

Proton-M crash sequence (screen capture from the video)

622,000 Kilograms of very toxic propellants are aboard a three-stage of the Proton rocket at the liftoff. Experts point to engine failure as the likely cause of the crash.

"It's either the control system or the engine that has caused the accident. If the accident occurred in the first 10 to 20 seconds, than the engine is likely to be the cause," a source in the space agency told RIA.

An Interfax-Kazakhstan source at the cosmodrome said the rocket was out of control from the moment it took off from the launch pad.

“In line with its program, once a malfunction was detected, the rocket boosted to take itself away from the launch pad and fell about one kilometer from it,” the source said, adding that initial telemetry data suggests that the problem occurred in one of the stability guidance jet engines.

There will be no launches from Baikonur for about two-three months, a source in Russia’s space industry told RIA Novosti news agency.

“There will be no launches of Proton-M rockets while the investigation is underway. In two-three days we will know what exactly happened to the rocket. This is a well-known rocket, and the reason for the crash is the human factor and a production failure,” the source said.

“We’ve had similar accidents at Baikonur before. After the area is cleaned up, launches will resume – in two-three months,” the source continued.

Proton-M crash (screen capture from the video)

Igor Marinin, Editor-in-Chief of Russia’s Cosmonautics News magazine told RT that there have not been any rocket crashes during the  first seconds of flight for at least ten years in the Russian space industry.  “This is a phenomenal accident,” he said.

The Proton-M uses highly toxic heptyl fuel, the expert said, but “it is burning out right now so the consequences will be minor. The major threat is poisonous fumes from the burning fuel and the major task now is to make sure that nobody gets into the heptyl smoke.”

The crashed Proton-M rocket employed a DM-03 booster, which was being used for the first time since December 2010, when another Proton-M rocket with the same booster failed to deliver yet another three GLONASS satellites into orbit, crashing into the Pacific Ocean some 1,500 kilometers from Honolulu.

After the 2010 crash, the investigative commission concluded that technicians miscalculated the amount of fuel needed for the DM-3 rocket booster.

Tuesday’s incident was the fifth launch of a Proton-M rocket in 2012 and the 388th overall launch of a Proton rocket.

The Proton-M booster rocket with a DM-03 (Roscosmos Press Service)

The next Proton-M launch is scheduled for July 21, though it will likely be delayed pending an investigation. It is supposed to deliver a commercial ASTRA 2E broadcast satellite for Europe into orbit.

GLONASS is a network of Russian navigation satellites designed to ensure global positioning, and is viewed as a direct rival to the American Global Positioning System (GPS). Its worldwide operation requires 24 working satellites.

There are currently 28 GLONASS satellites in orbit, 23 of which are in operation, four in reserve and one next generation GLONASS-K satellite undergoing tests.

By 2020 Russia intends to spend over 300 billion rubles ($9 billion) on Glonass.

Russia has already conducted 15 launches from Baikonur and Plesetsk cosmodromes in 2013 and 23 more launches are expected to be made by the end of the year.

ROSCOSMOS Press Release: http://www.federalspace.ru/main.php?id=2&nid=20191

Images, Video, Text, Credits: Press Service of the Russian Federal Space Agency (Roscosmos PAO) / ROSCOSMOS / RIA Novosti.

Greetings, Orbiter.ch

Space Station Gets an Attitude Adjustment for Solar Science

ISS - International Space Station patch.

July 1, 2013

The sun lightens our world and enlightens our scientists as they look to our closest star for a better understanding of solar activity and what it means for our planet. Unique data from solar studies help researchers build on their knowledge of the Earth’s atmosphere and climate change. June 30 marked the second time the International Space Station literally went out of its way to accommodate this research by providing a better viewing opportunity to meet Solar facility science objectives.

“The European scientists requested that we reposition the station slightly because by having this period of time they could bridge over the two Solar observing visibility windows, allowing them to view the sun for a full solar rotation without interruption,” said International Space Station Program Scientist Julie Robinson, Ph.D. “The International Space Station Program took a look at the request and was able to change the station's position to increase science return.”

Image above: The International Space Station's change in position accommodates solar research from an orbital vantage point by lengthening the window of time to observe a full rotation of the sun for data collection from the Solar observatory. Image Credit: NASA.

The first station adjustment took place between Dec. 1 and 11, 2012, when the attitude of the orbiting laboratory was temporarily altered by about 7.5 degrees to provide a longer viewing time of the sun for the European Space Agency’s (ESA) Solar observatory on the External Payload Facility of the Columbus module. This summer adjustment to the space station’s position offers an additional opportunity to follow an entire solar rotation, approximately 27 days as determined by viewing sunspots from Earth.

“A very important contribution from the Solar ‘bridging’ measurements is the possibility it brings to perform inter-comparisons over an entire period of a Solar rotation with data from other solar instruments in orbit (e.g. a comparison of ESA’s Solar-SOLACES data and NASA's SDO/EVE data),” said ESA Solar Project Scientist Astrid Orr, Ph.D. “The December bridging already shows that these particular data sets agree extremely well with each other.”

Image above: NASA's Solar Dynamics Observatory (SDO) captured this image of an M5.7-class flare on May 3. This image shows light in the 131-angstrom wavelength, a wavelength of light that can show material at the very hot temperatures of a solar flare and that is typically colorized in teal. Image Credit: NASA.

The measurements for this Solar window observation are planned to run from June 18 to July 23, with the bridging event beginning on July 1. Normally viewing from the station only allows for short visibility windows of 10 to 12 days at a frequency of about once a month. After that timeframe, the observation window is blocked by the structure of the station itself, such as the solar arrays. Changing the position of the station increases the visibility of the sun, enabling scientists to view a full rotation from the orbital vantage point.

The Solar observatory launched to the station in February 2008 and currently houses two active investigations: Solar-SOLACES and Solar-SOLSPEC. Solar-SOLACES, which stands for Solar Auto-Calibrating Extreme UV/UV Spectrophotometers, collects data between 15 and 220 nanometers (nm) for extreme-ultraviolet/ultraviolet solar spectral irradiance. Solar-SOLSPEC, which stands for Solar Spectral Irradiance Measurements, measures between 180 to 3,000 nm for absolute solar spectral irradiance. Solar irradiance measurements tell scientists how much energy reaches Earth’s atmosphere from the sun during any given period of time.

Image above: A view of the zenith and forward sides of the International Space Station’s Columbus module showing the Monitoring on the External Payload Facility of Columbus (Solar), European Technology Exposure Facility (EuTEF) and Materials International Space Station Experiment (MISSE) facility. Image Credit: NASA.

The goal of these studies is to gain accurate solar spectral irradiance measurements to understand variations in our environment due to solar radiation. With solar activity increasing, the timing of this adjustment will accommodate the investigations for improved science returns. These data can contribute to improved modeling of sunspots and other solar phenomena. The information also contributes to atmospheric and climatic models, helping researchers to predict sun and space weather activities.

“The bridging makes it possible for the scientists to develop a method for ‘melting’ both sets of data into one reference set of data in absolute physical values for the science community, which includes both solar physicists and climate researchers,” said Orr.

The June viewing window coincides with the Northern Hemisphere summer solstice—on the other side of the globe, this time period corresponds to the Southern Hemisphere winter solstice. During both the summer and winter solstices the gap between viewing opportunities is less than 10 days, making it possible to bridge two visibility windows for a full sun rotation with minimum adjustment to the station's attitude angle.

The image above shows the location along with a close up view of the European Space Agency's European Technology Exposure Facility (EuTEF) platform located externally on the Columbus module. EuTEF houses nine experiments including Earth Viewing Camera (EVC). Image Credit: NASA.

The station’s orbit is turned at this time so that it is mostly sunlit, giving the instruments optimal opportunity for measurements. This will help to meet the Solar science team’s requirements to observe the sun through a full solar rotation, which would not be possible without the station adjustment, due to orbital mechanics and maneuver limitations of the Solar platform. After the observations complete, the station will return to its standard attitude. The investigations will continue to collect data using shorter observation periods.

“The Solar detectors perform very accurate measurements of the sun's flux: they are measurements in absolute values. In other words, the real amount of flux emitted by the sun in physical units,” said Orr. “This may sound trivial but it is in fact quite difficult to achieve. Many detectors looking at the sun provide only measurements in relative units. On the other hand, absolute measurements are important in order to understand the amount of energy that the sun is emitting and that we receive at the Earth. Like, if somebody has a fever and you are trying to measure their temperature: you can put your hand on their forehead and say that it's hot, or else you can actually measure the temperature with a thermometer. It is useful if the thermometer that you are using has its units stated correctly, otherwise your measurement will be of little use.”

This is an exciting time for solar scientists because with the full solar rotation observation, they will have a second chance to compare their Solar data with results from other measurement instruments. This will give researchers a more complete data set to work with for their studies on the impact of the sun’s radiation on our planet’s environment.

ESA requested an additional temporary change to the space station’s attitude for a third viewing opportunity during Northern Hemisphere's winter solstice, which takes place from Nov. 29 to Dec. 8. “The Solar science team estimates that three ‘science visibility window’ bridging maneuvers will provide them a sufficient level of statistics in their measurements,” said Orr. “Three is a minimum, but it would be sufficient.”

For more information about the International Space Station, visit: http://www.nasa.gov/mission_pages/station/

Images (mentioned), Text, Credits: NASA / International Space Station Program Science Office / NASA's Johnson Space Center / Jessica Nimon.

Greetings, Orbiter.ch

Goodbye Herschel

ESA / NASA - Herschel Exploring the Cold Universe patch.

1 July 2013

 Herschel observed from the ground

This tiny dot against the streaking star field is one of the last views that ground-based observers will see of ESA’s iconic Herschel space observatory.

Herschel spent over three years taking stunning images of the Universe in far infrared wavelengths, but in April the spacecraft depleted the last of its helium coolant, concluding science operations.

After this, the spacecraft operations team performed a series of engineering tests. A series of thruster burns moved it from its orbit around the L2 point 1.5 million kilometres from the Earth, and into a heliocentric orbit. Finally, in June, the spacecraft was switched off.

As well as being tracked by ESA ground stations throughout its mission, amateur astronomers have also enjoyed spotting the spacecraft.

Last week, as Herschel began moving away from Earth, astronomers Nick Howes and Ernesto Guido from the Remanzacco Observatory used the 2m diameter Faulkes Telescope North in Hawaii to image the spacecraft.

The observation was a particular challenge as the final manoeuvres made by the ESA flight control team resulted in the observatory being at a slightly different position on the sky compared to that predicted by existing orbital data.

Herschel space observatory

But the imaging campaign was successful, as seen in the image presented here, with Herschel indicated by the two lines to the right of centre. Stars appear as streaks because the astronomers were tracking the motion of Herschel through the sky.

Herschel’s new orbit will send it around the Sun, coming back into Earth’s neighbourhood around 13 years from now.

Determining an accurate orbit now is important, because its increasing distance will make it fainter and much harder to keep track of in the intervening years.

Related links:

Faulkes Telescope Project: http://www.faulkes-telescope.com/

Herschel: http://www.esa.int/Our_Activities/Operations/Herschel

Herschel overview: http://www.esa.int/Our_Activities/Space_Science/Herschel_overview

Online Showcase of Herschel Images OSHI: http://oshi.esa.int/

Herschel in depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=16

Herschel Science Centre: http://herschel.esac.esa.int/

Images, Text, Credits: ESA / N. Howes / E. Guido / Faulkes Telescope / LCOGT.

Best regards, Orbiter.ch