Newly Expanded Station Crew Tackles Research, Spacewalk Preps

ISS - Expedition 41 Mission patch.

September 29, 2014

The International Space Station’s Expedition 41 crew, which doubled the number of humans in space when three new crew members arrived last week, began its first full workweek as a six-person crew Monday with biological research and preparations for a pair of U.S. spacewalks.

Flight Engineers Barry Wilmore, Alexander Samokutyaev and Elena Serova joined their Expedition 41 crewmates on the station early Friday following a six-hour, four-orbit trek aboard their Soyuz TMA-14M spacecraft from the launch site at the Baikonur Cosmodrome in Kazakhstan. Wilmore, Samokutyaev and Serova are slated to spend 5 ½ months aboard the station. Commander Max Suraev and Flight Engineers Reid Wiseman and Alexander Gerst, who arrived on May 28, will return to Earth in November.

Read more about launch and docking of new station trio: http://orbiterchspacenews.blogspot.ch/2014/09/expedition-41-welcomes-new-trio-aboard.html

Shortly after the usual 2 a.m. EDT reveille, the entire crew conducted body mass measurements, inspected their orbital home and participated in a daily planning conference with the flight control teams around the world to review the day’s activities.

Image above: Flight Engineer Reid Wiseman posted this Twitter photo showing Flight Engineers Barry Wilmore (left) and Alexander Gerst at work in the Kibo laboratory of the International Space Station. Image Credit: NASA.

For Wiseman, Gerst and Wilmore, most of those activities were centered primarily on gearing up for their upcoming spacewalks. During an Oct. 7 excursion outside the station, Wiseman and Gerst will transfer a previously uninstalled pump module from its temporary stowage location to the External Stowage Platform-2. The two spacewalkers also will install the Mobile Transporter Relay Assembly that adds the capability to provide “keep-alive” power to the Mobile Servicing System when the Mobile Transporter is moving between worksites.

Wiseman and Gerst spent some time reviewing the procedures for that spacewalk and later participated in a conference call with spacewalk specialists on the ground.

Wilmore meanwhile began “scrubbing” the cooling loops of the U.S. spacesuits, including the Liquid Cooling and Ventilation Garment that he will wear under his own spacesuit when he joins Wiseman for the second Expedition 41 spacewalk on Oct. 15. Wiseman completed the spacesuit water recharge in the afternoon.

Gerst also checked in on the Zebrafish Muscle study as he assessed the water condition inside the Aquatic Habitat, which is housing a school of spacefaring fish popularly known in the aquarium trade as zebra danios. The goal of the study is to determine whether zebrafish muscles weaken in microgravity similarly to human muscles and, if so, isolate the cause. Results from the Zebrafish Muscle investigation may help identify molecular changes involved in the deterioration of muscles exposed to microgravity. The findings could potentially benefit patients on extended bed rest or with limited mobility. In addition, this information would aid researchers in developing countermeasures for muscle weakness in astronauts living in microgravity during extended missions.

On the Russian side of the complex, Serova transferred test samples from the Kaskad cell cultivation experiment, while Samokutyaev performed a study of hardware designed to provide aseptic conditions for biotechnological experiments.

Meanwhile, Commander Suraev stowed trash and unneeded items for disposal inside the Progress 56 cargo ship currently attached to the Pirs docking compartment. The Russian space freighter, which delivered nearly three tons of cargo when it docked to the station’s Pirs docking compartment on July 23, will undock from the station in late October for a destructive re-entry over the Pacific Ocean.

Image above: Flight Engineer Reid Wiseman tweeted this photo of the International Space Station's Canadarm2 and the Special Purpose Dexterous Manipulator preparing to remove external cargo from the SpaceX Dragon resupply vehicle. Image Credit: NASA.

All six crew members teamed up in the afternoon for a review of their roles and responsibilities during an emergency aboard the station.

As the newest crew members, Wilmore, Samokutyaev and Serova also had an hour set aside on their own to learn the ropes of their orbiting home.

While the crew worked inside the station, the robotics officer at Houston’s Mission Control Center maneuvered the Canadarm2 robotic arm and its Special Purpose Dexterous Manipulator to the trunk of the recently arrived SpaceX Dragon cargo ship attached to the Earth-facing port of the Harmony node. There the arm was commanded to grapple and extract an adapter mechanism from Dragon’s trunk and install it to a bracket on the front of the Columbus module. On Tuesday, the ISS-Rapid Scatterometer, or RapidScat, will be removed robotically from the trunk for installation on the adapter device.

Designed to monitor ocean winds from the station’s vantage point, RapidScat is a space-based scatterometer that uses radar pulses reflected from the ocean's surface from different angles to calculate surface wind speed and direction. This information will be useful for weather forecasting and hurricane monitoring.

Related links:

Zebrafish Muscle study: http://www.nasa.gov/mission_pages/station/research/experiments/65.html

ISS-Rapid Scatterometer, or RapidScat: http://www.nasa.gov/mission_pages/station/research/experiments/1067.html

For more information about the International Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Video, Text, Credits: NASA.

Cheers, Orbiter.ch

Cassini Watches Mysterious Feature Evolve in Titan Sea

NASA / ESA - Cassini-Huygens Mission to Saturn & Titan patch.

September 29, 2014

Image above: These three images, created from Cassini Synthetic Aperture Radar (SAR) data, show the appearance and evolution of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon seas on Saturn's moon Titan. Image Credit: NASA/JPL-Caltech/ASI/Cornell.

NASA's Cassini spacecraft is monitoring the evolution of a mysterious feature in a large hydrocarbon sea on Saturn's moon Titan. The feature covers an area of about 100 square miles (260 square kilometers) in Ligeia Mare, one of the largest seas on Titan. It has now been observed twice by Cassini's radar experiment, but its appearance changed between the two apparitions.

Images of the feature taken during the Cassini flybys are available at: http://photojournal.jpl.nasa.gov/catalog/PIA18430

The mysterious feature, which appears bright in radar images against the dark background of the liquid sea, was first spotted during Cassini's July 2013 Titan flyby. Previous observations showed no sign of bright features in that part of Ligeia Mare. Scientists were perplexed to find the feature had vanished when they looked again, over several months, with low-resolution radar and Cassini's infrared imager. This led some team members to suggest it might have been a transient feature. But during Cassini's flyby on August 21, 2014, the feature was again visible, and its appearance had changed during the 11 months since it was last seen.

Scientists on the radar team are confident that the feature is not an artifact, or flaw, in their data, which would have been one of the simplest explanations. They also do not see evidence that its appearance results from evaporation in the sea, as the overall shoreline of Ligeia Mare has not changed noticeably.

The team has suggested the feature could be surface waves, rising bubbles, floating solids, solids suspended just below the surface, or perhaps something more exotic.

The researchers suspect that the appearance of this feature could be related to changing seasons on Titan, as summer draws near in the moon's northern hemisphere. Monitoring such changes is a major goal for Cassini's current extended mission.

Cassini-Huygens spacecraft. Image Credits: NASA/JPL-Caltech

“Science loves a mystery, and with this enigmatic feature, we have a thrilling example of ongoing change on Titan," said Stephen Wall, the deputy team lead of Cassini's radar team, based at NASA's Jet Propulsion Laboratory in Pasadena, California. "We’re hopeful that we’ll be able to continue watching the changes unfold and gain insights about what’s going on in that alien sea.”

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

For more information about Cassini and its mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov and http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Images (mentioned), Text, Credits: NASA / JPL / Preston Dyches.

Greetings, Orbiter.ch

CERN turns 60, celebrates peaceful collaboration for science

CERN - 60 Years logo.

September 26, 2014

Today, CERN, the European Organization for Nuclear Research, is blowing out 60 candles at an event attended by official delegations from 35 countries. Founded in 1954, CERN is today the largest particle physics laboratory in the world and a prime example of international collaboration, bringing together scientists of almost 100 nationalities.

CERN and science for peace

Video above: "CERN and science for peace" - an account of the history of CERN (Video: CERN).

CERN’s origins can be traced back to the late 1940s. In the aftermath of the Second World War, a small group of visionary scientists and public administrators, on both sides of the Atlantic, identified fundamental research as a potential vehicle to rebuild the continent and to foster peace in a troubled region. It was from these ideas that CERN was born on 29 September 1954, with a dual mandate to provide excellent science, and to bring nations together. This blueprint for collaboration has worked remarkably well over the years and expanded to all the continents.

“For six decades, CERN has been a place where people can work together, regardless of their culture and nationality. We form a bridge between cultures by speaking a single universal language and that language is science,” said CERN Director-General Rolf Heuer. “Indeed, science is an essential part of culture. Maestro Ashkenazy, conducting the European Union Youth Orchestra here today puts it most eloquently in saying that while music reflects the reality of our spiritual life and tries to convey to us the essence of our existence, science’s mission is extremely similar; it also tries to explain the world to us.”

CERN: 60 years in search of the secrets of matter

CERN came into being on 29 September 1954 when its convention, agreed by 12 founding Member States, came into force. Over the years and with its continuing success, CERN has attracted new countries and become a truly global organization, Today it has 21 Member States and more than 10,000 users from all over the world, and more countries have applied for membership.

“Over time, CERN has become the world’s leading laboratory in particle physics, always oriented towards, and achieving, excellence,” said President of CERN Council Agnieszka Zalewska.

CERN’s business is fundamental physics, aiming to find out what the universe is made of and how it works. Since 1954, the landscape of fundamental physics has dramatically changed. Then, knowledge of matter at the smallest scales was limited to the atom of the nucleus. In 60 years, particle physicists have advanced knowledge of forces and matter at the smallest scales, developed a sound theory based on this knowledge – the Standard model – and improved the understanding of the universe and its beginnings.

CERN and the rise of the Standard Model

Video above: "CERN and the rise of the Standard Model" - CERN's contributions to research in physics (Video: CERN).

Over the years, physicists working at CERN have contributed to this progress as a series of larger and ever more powerful accelerators have allowed researchers to explore new frontiers of energy. Among the many results achieved, some discoveries have dramatically improved comprehension of the fundamental laws of nature and pushed forward technologies. These include the discovery of the particle carriers of the weak force, rewarded with a Nobel Prize for Carlo Rubbia and Simon van der Meer in 1984, the invention of the World Wide Web by Tim Berners-Lee in 1989, the development of a revolutionary particle detector by Georges Charpak, rewarded by a Nobel Prize in 1992, and the discovery of the Higgs boson in 2012, proving the existence of the Brout-Englert-Higgs mechanism, which led to a Nobel Prize for Peter Higgs and François Englert in 2013.

Knowledge and technology: from CERN to society

Video above: "Knowledge and technology: from CERN to society" - applications of CERN's research (Video: CERN).

Today CERN operates the world’s leading particle accelerator, the Large Hadron Collider. With the restart of the LHC next year at new record energy, CERN will continue to seek answers to some of the most fundamental questions about the universe.

Related links:

CERN Member States: http://home.web.cern.ch/about/member-states

Standard model: http://home.web.cern.ch/about/physics/standard-model

World Wide Web: http://home.web.cern.ch/topics/birth-web

Higgs boson: http://home.web.cern.ch/topics/higgs-boson

Brout-Englert-Higgs mechanism: http://home.web.cern.ch/about/physics/w-boson-sunshine-and-stardust

Large Hadron Collider: http://home.web.cern.ch/topics/large-hadron-collider

Image, Videos (mentioned), Text, Credits: CERN / Sotirios Boutas.

Greetings, Orbiter.ch

Cold Atom Laboratory Creates Atomic Dance

NASA logo.

September 26, 2014

Like dancers in a chorus line, atoms' movements become synchronized when lowered to extremely cold temperatures. To study this bizarre phenomenon, called a Bose-Einstein condensate, researchers need to cool atoms to a temperature just above absolute zero – the point at which atoms have the least energy and are close to motionless.

The goal of NASA's Cold Atom Laboratory (CAL) is to study ultra-cold quantum gases in a facility instrument developed for use on the International Space Station. Scientists will use the facility to explore how differently atoms interact in microgravity when they have almost no motion due to such cold temperatures. With less pull toward the ground from Earth, matter can stay in the form of a Bose Einstein condensate longer, giving researchers the opportunity to observe it better.

Image above: Artist’s concept of an atom chip for use by NASA’s Cold Atom Laboratory (CAL) aboard the International Space Station. CAL will use lasers to cool atoms to ultracold temperatures. Image Credit: NASA.

The CAL team announced this week that it has succeeded in producing a Bose-Einstein condensate at NASA's Jet Propulsion Laboratory, a key breakthrough for the instrument leading up to its debut on the space station in late 2016.

A Bose-Einstein condensate is a collection of atoms in a dilute gas that have been lowered to extremely cold temperatures and all occupy the same quantum state, in which all of the atoms have the same energy levels. At a critical temperature, atoms begin to coalesce, overlap and move in synch. The resulting condensate is a new state of matter that behaves like a giant - by atomic standards - wave.

"It’s official. CAL's ground testbed is the coolest spot at NASA's Jet Propulsion Laboratory at 200 nano-Kelvin [200 billionths of 1 Kelvin]," said CAL Project Scientist Rob Thompson at JPL in Pasadena, California. "Achieving Bose-Einstein condensation in our prototype hardware is a crucial step for the mission."

Image above: The Cold Atom Laboratory (CAL) conducted its first environmental test series to demonstrate robustness to the launch vehicle environment for flight like electronics, fiber optics, and vacuum system at the JPL Environmental Test Facility. Image Credit: NASA.

Although these quantum gases had been created before elsewhere on Earth, CAL will explore the condensates in an entirely new regime: the microgravity environment of the space station. It will enable unprecedented research in temperatures colder than any found on Earth.

In the station's microgravity environment, long interaction times and temperatures as low as one picokelvin (one trillionth of one Kelvin, or 293 trillion times less than room temperature) should be achievable. That's colder than anything known in nature, and the experiments with CAL could potentially create the coldest matter ever observed in the universe. These breakthrough temperatures unlock the potential to observe new quantum phenomena and test some of the most fundamental laws of physics. The CAL investigation could advance our knowledge in the development of exquisitely sensitive quantum detectors, which could be used for monitoring the gravity of the Earth and other planetary bodies, or for building advanced navigation devices.

Image above: This sequence of false-color images shows the formation of a Bose-Einstein condensate in the Cold Atom Laboratory prototype at NASA's Jet Propulsion Laboratory as the temperature gets progressively closer to absolute zero. Red in each figure indicates higher density. Image Credit: NASA/JPL-Caltech.

"Ultra-cold atoms will also be useful for space-based optical clocks that will be future time standards,” Thompson said.

First observed in 1995, Bose-Einstein condensation has been one of the "hottest" topics in physics ever since. The condensates are different from normal gases; they represent a distinct state of matter that starts to form typically below a millionth of a degree above absolute zero. Familiar concepts of "solid," "liquid," and "gas" no longer apply at such cold temperatures; instead, atoms do bizarre things governed by quantum mechanics, such as behaving as waves and particles at the same time.

CAL researchers used lasers to optically cool atoms of the chemical element rubidium to temperatures almost a million times colder than that of the depths of space. The atoms were then magnetically trapped, and radio waves were used to cool the atoms 100 times lower. The radiofrequency radiation acts like a knife, slicing away the hottest atoms from the trap so that only the coldest remain.

The research is at the point where this process can reliably create a Bose-Einstein condensate in just seconds.

Image above: Members of the Cold Atom Laboratory team at NASA's Jet Propulsion Laboratory are seen here with their ground-based testbed, which can reliably create a Bose-Einstein condensate. Pictured from left to right, Anita Sengupta, Ethan Elliott, Rob Thompson and Markus Krutzik. Image Credit: NASA/JPL-Caltech.

"This was a tremendous accomplishment for the CAL team. It confirms the fidelity of the instrument system design and provides us a facility to perform science and hardware verifications before we get to the space station," said CAL project manager Anita Sengupta of JPL.

JPL is developing the Cold Atom Laboratory sponsored by the International Space Station Program at NASA's Johnson Space Center in Houston. The Space Life and Physical Sciences Division of NASA's Human Exploration and Operations Mission Directorate at NASA Headquarters in Washington manages the Fundamental Physics Program.

The Coolest Spot in the Universe

While so far CAL researchers have created Bose-Einstein condensates with rubidium atoms, eventually they also will add in potassium.

"The behavior of two condensates mixing together will be fascinating for physicists to observe, especially in space," Sengupta said.

Besides merely creating Bose-Einstein condensates, CAL provides a suite of tools to manipulate and probe these quantum gases in a variety of ways. CAL has a unique role as a facility for the atomic, molecular and optical physics community to study cold atomic physics in microgravity, said David Aveline of JPL, CAL ground testbed lead.

"Instead of a state-of-the-art telescope looking outward into the cosmos, CAL will look inward, exploring physics at the atomic scale," Aveline said.

You may have thought that the coldest place in the universe might be a vast tract of space between distant stars. But in a couple of years, the coldest place we know of will be orbiting our own planet, creating atomic dances to dazzle the scientific imagination.

Related links:

NASA's Cold Atom Laboratory (CAL): http://coldatomlab.jpl.nasa.gov/

International Space Station: http://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Video, Text, Credits: NASA / JPL / Elizabeth Landau.

Best regards, Orbiter.ch

Good and bad news for our atmosphere

ESA- ENVISAT Mission logo.

29 September 2014

Data from ESA’s veteran Envisat satellite show ups and downs in the concentrations of the air pollutant nitrogen dioxide and the climate-relevant greenhouse gas carbon dioxide across the globe.

While Europe and North America show a decrease in emission trends between 2003 and 2011, emissions related to economic growth in East Asia continue to rise – but with a reduction in nitrogen oxides emitted per amount of carbon dioxide.

Emission pattern and trends

This demonstrates the use of cleaner technology in East Asia.

Nitrogen oxides are generated during the high-temperature combustion of fossil fuels in automobiles and industrial machinery. They contribute significantly to a reduction of air quality and can be the cause of respiratory problems.

At the same time, these sources release large amounts of carbon dioxide. Carbon dioxide is toxic only at very high concentrations, but is the most important man-made greenhouse gas, leading to global warming and its related consequences.

In a study published yesterday in Nature Geoscience, scientists from the University of Bremen in Germany used data from the Sciamachy instrument on ESA’s Envisat satellite to measure nitrogen dioxide and carbon dioxide trends from 2003 to 2011. They also exploited  Sciamachy-based data products generated within the ‘GHG-CCI’ project under ESA’s Climate Change Initiative.

“Nitrogen dioxide has a relatively short lifetime – hours – compared to carbon dioxide, which lasts decades, and is a suitable tracer of recently emitted carbon dioxide from fossil fuel combustion,” explained Maximilian Reuter, lead author of the study.

“Sciamachy measured nitrogen dioxide and carbon dioxide simultaneously. We used a spatial high-pass filtering method to isolate the anthropogenic carbon dioxide signal from overlaying signals due to uptake and release of carbon dioxide by vegetation.”

Day-of-week dependence of carbon dioxide

Using this method, the scientists were able to better see where and when carbon dioxide was emitted. For example, it showed that less carbon dioxide from local anthropogenic sources is emitted during weekends in Europe and North America compared to week days.

“This has never been observed from space before and shows how accurate the used method is,” said Dr Reuter.

Although Envisat’s mission ended in 2012, a decade of data from its 10 instruments is still being exploited for studies on Earth’s atmosphere, land, oceans and ice caps.

“Unfortunately, none of the existing nor any of the planned near-future satellites are designed to directly observe carbon dioxide emissions of cities, power plants, volcanoes or other important emission hot spots,” said Michael Buchwitz, co-author of the study and GHG-CCI scientific leader.

“This will only be possible with the proposed mission CarbonSat.”

CarbonSat is one of the two candidates for ESA’s eighth Earth Explorer satellite.

Using the unique spectroscopic fingerprint of carbon dioxide and methane, CarbonSat aims to image these two strong greenhouse gases at very high resolution. The mission would lead to a better understanding of the sources and sinks of atmospheric carbon dioxide and methane.

Related links:

Paper: Decreasing NOx relative to CO2 emissions in East Asia inferred from satellite observations: http://dx.doi.org/10.1038/ngeo2257

University of Bremen: http://www.uni-bremen.de/en.html

CarbonSat at University of Bremen: http://www.iup.uni-bremen.de/carbonsat/

GHG-CCI: http://www.esa-ghg-cci.org/

Related missions:

Envisat: http://www.esa.int/Our_Activities/Observing_the_Earth/Envisat

Graphics, Text, Credits: ESA / University of Bremen.

Greetings, Orbiter.ch

Craters on the edge

ESA - SMART 1 Mission patch.

29 September 2014

Craters on the edge

The greyscale pattern of dark and light blotches on the Moon is a familiar sight to stargazers. However, there are regions that remained relatively mysterious to us until surprisingly recently – most notably the Moon’s polar regions, which astronomers have dubbed ‘Luna Incognita’, or ‘the unknown Moon’.

In recent years, missions including ESA’s SMART-1 have shed light on these regions of the lunar surface, and they are now better known.

This mosaic covers about 700 km by 220 km and was taken by the Advanced Moon Imaging Experiment on SMART-1. It shows a trio of craters very near to the Moon’s north pole, on the edge of the Luna Incognita. From right to left, these craters are named Plaskett, Rozhdestvenskiy and Hermite.

Hermite (104 km diameter) is perched right on the edge of the Moon’s northern limb, while Plaskett (109 km diameter) and Rozhdestvenskiy (177 km diameter) overlap the lunar far side.

We only ever see the same hemisphere of the Moon due to ‘tidal locking’ – this causes the Moon to orbit Earth once in the same time it takes to spin once about its axis. However, we actually see around 59% of the lunar surface owing to factors such as the eccentricity of the Moon’s orbit, its orientation with respect to Earth, and the rotation of Earth. Over time, these little variations add up and the Moon appears to oscillate slowly, allowing us to peer a bit further around the lunar surface at its edges. This effect is known as libration. 

ESA’s SMART-1

Plaskett’s location is within one of the zones that seems to oscillate. For just a few days during a few months each year, Earth can be seen from Plaskett’s northern rim – one of the key reasons it may make a suitable lunar outpost for simulating a mission to Mars. This infrequent contact would be ideal to test how astronauts cope with being isolated from Earth, without requiring the additional separation or risk involved in actually travelling to the Red Planet.

For more information about SMART-1, visit: http://www.esa.int/Our_Activities/Space_Science/SMART-1

Images, Text, Credits: ESA / J. Huart / SMART-1 / AMIE camera team/Space Exploration Institute.

Cheers, Orbiter.ch

Rocket Proton-M and spacecraft Luch was launched from the Baikonur Cosmodrome

ROSCOSMOS logo.

09/28/2014

Rocket Proton-M and spacecraft Luch launch

September 28, 2014 at 00 hours 23 minutes Moscow time from launch pad 81 Baikonur cosmodrome, starting calculations of rocket-space industry, the launch of Russian rocket Proton-M carrier rocket with Breeze-M and spacecraft Olymp or Luch.

Proton-M night launch (illustration)

After the regular separation from the third stage of the launch vehicle orbital assembly as part of the Republic of Belarus, Breeze-M and Olymp continues to autonomous flight. Further removal of the spacecraft to the target orbit at the expense of the propulsion system booster.

Luch or Olymp spacecraft

At 09:26 Moscow time spacecraft Luch cleanly separated from the upper stage Breeze-M and went into the desired orbit.

Editor note:

Only known about the Olymp satellite its its manufacturer, ISS Reshetnev, and a late change to its name, now referred to as Luch Satellite, possibly in an attempt to camouflage its military role since Luch is the name used for civilian data relay satellites operating from Geostationary Orbit. Unconfirmed details on Olymp indicate that the spacecraft is based on the Ekspress-2000 satellite platform carrying a multi-purpose payload to provide secure communications to the Russian Government and will possibly test out electronic intelligence systems. After launch, Olymp will be tracked in orbit to confirm its secret destination that likely is a direct insertion into a Geosynchronous Orbit.

ROSCOSMOS Press Releases:

http://www.federalspace.ru/20960/
http://www.federalspace.ru/20961/

Images, Video, Text, Credits: Roscosmos press service / ROSCOSMOS / Translation: Orbiter.ch Aerospace.

Greetings, Orbiter.ch