Saturday, January 31, 2015

ESA Integral manoeuvres to improve future observations

Credit: ESA

ESA’s Integral observatory is able to detect gamma-ray bursts, the most energetic phenomena in the Universe.

Since 2002, ESA’s Integral spacecraft has been observing some of the most violent events in the Universe, including gamma-ray bursts and black holes.

While it still has years of life ahead, its fuel will certainly run out one day.

Integral, one of ESA’s longest-serving and most successful space observatories, has begun a series of four thruster burns carefully designed to balance its scientific life with a safe reentry in 2029.

That seems far off, but detailed planning and teamwork now will ensure that the satellite’s eventual entry into the atmosphere will meet the Agency’s guidelines for minimising space debris.

Making these disposal manoeuvres so early will also minimises fuel usage, allowing ESA to exploit the valuable satellite’s lifetime to the fullest.

This is the first time that a spacecraft’s orbit is being adjusted, after 12 years in space, to achieve a safe reentry 15 years in the future, while maximising valuable science return for the subsequent seven to eight years.

“Our four burns will use about half of the estimated 96 kg of fuel available,” says Richard Southworth, spacecraft operations manager at ESA’s Space Operations Centre, ESOC, in Darmstadt, Germany.

“This will influence how Integral’s orbit evolves, so that even after we run out of propellant we will still have a safe reentry in February 2029 as a result of natural orbit decay.

“No further manoeuvres are required between now and then and Integral can continue to operate.”

Debris Mitigation
The latest ESA debris guidelines require that a satellite must be disposed of in such a way that it poses no risk to other satellites in protected orbital regions for more than 25 years.

Although Integral’s early launch date, in 2002, means it is not required to stick to the guidelines, they were followed for planning the disposal.

“We have done a great deal of modelling for Integral’s reentry in 2029,” says Klaus Merz of ESA’s Space Debris Office.

“We’re confident that this month’s manoeuvres will put it on track for a future safe reentry at latitudes in the far south, reducing risk far below guideline levels.”

Without these firings, the fuel supply would run out in perhaps 12–16 more years, after other essentials such as power end Integral's working life, but the satellite would not reenter for up to 200 years, which would present a hazard to other missions.

NASA Delta II Launch of SMAP

The Delta II rocket lifts off from Space Launch Complex 2 at Vandenberg Air Force Base carrying the Soil Moisture Active Passive (SMAP), satellite on a mission to measure and map the Earth's soil moisture distribution and freeze/thaw state with unprecedented accuracy. Liftoff was at 6:22 a.m. PST (9:22 a.m. EST).

The unfolded solar arrays to power SMAP and the golden feedhorn for its radar and radiometer are visible in this image taken during assembly and testing.

Credit: NASA, JPL.

In orbit graphic of SMAP satellite prior to third stage burn for orbit insertion and booster decoupling.

Credit: NASA,

Thursday, January 29, 2015

The Space Billboard: Innovation or Pollution of the Earth's skies

SpaceBillboard, a supporter of innovative space research, is set to launch the world's first billboard in space in a milestone that marks the increasing importance of CubeSats in Space Exploration.

Researchers at KU Leuven University in Belgium came up with the novel idea of launching a real billboard into space to help fund their research on a new line up of NexGen satellites called CubeSats.

A CubeSat is small, about the size of a milk carton - and lightweight, which makes them cheaper to build and launch.

A CubeSat is the perfect answer for universities and start-ups to get involved in space research, one of the bedrock platforms for research on advanced technology solutions.

European Space Agency ESA and NASA in the US have active CubeSat programs that help drive the development and adoption of emerging technologies in support of new business solutions.

Tjorven Delabie, co-founder of SpaceBillboard said: "We are talking about an out-of-this-world project, that allows companies to bring their brand into space."

"The idea is catching on, and SpaceBillboard has already secured a number of contracts for companies to have their message on their own billboard in space."

The launch of the billboard is scheduled for the beginning of 2016, to be launched from Alcantara in Brazil.

Highest and fastest
The messages on the SpaceBillboard will be the highest and the fastest ever seen in the industry, flying at 27,400 kph at an altitude of 500 km.

The Billboard will orbit the Earth 15 times a day, becoming the first advertisements that literally bring their message around the world.

Although the billboard will not be visible from Earth, all messages will be continuously visible on the SpaceBillboard website as well as used in the customers' branding campaigns.

Marketing and Science
SpaceBillboard is a new kind of crowdfunding project where private and corporate donors help push space research forward. For companies, buying one or more of the 400 available squares on the billboard is a perfect opportunity to showcase their innovative spirit. At euro 2500 per square for the launch premiere, SpaceBillboard is a fantastic way to bring together experts from academia and industry to support the future of technology.

Personal Messages
Inspiring people about space research is an important part of SpaceBillboard's mission. Therefore, you can also put a personal message on the billboard yourself.

Sending a personal message into space costs euro 1/character. So far, many have already signed up to share their message, most of them are messages of love.

Into Space
Once the SpaceBillboard has been sold out, it will be put on the CubeSat. This satellite will also perform a valuable scientific mission.

The CubeSat will be deployed into a high inclination, low Earth orbit, and is expected to operate in orbit for up to ten years.

After that, the satellite will burn up in the atmosphere, ensuring that no space debris is left behind.

Wednesday, January 28, 2015

MARS Habitation Fire ends GreenHab mission

Mars Desert Research Station (MDRS) GreenHab following a fire on Dec. 29, 201

Credit: Nick Orenstein

Four crewmembers simulating a mission on Mars dealt with a real-life emergency late last month, a greenhouse fire so strong that flames reached at least 10 feet (3 meters) high.

On Dec. 29, the first day of their mission, the crew noticed an unusual power surge in their habitat at the Mars Desert Research Station (MDRS), in the Utah desert near the small town of Hanksville.

A few minutes later, somebody spotted smoke coming from the greenhouse.

Crew commander Nick Orenstein, an experienced camper who has built bonfires in the past, ran outside to take a look.

He said he figured the group could take on the fire, because the smoke was blowing away from the habitat, and only one shelf inside the greenhouse was aflame.

At that time, the fire was about the size of three overstuffed chairs.

"This is a moment where instinct took over, the instinct of fight or flight, and we had fight," Orenstein told reporters. "There really wasn't a question at the moment."

It took the crew about half an hour to bring the fire under control.

Orenstein and crew engineer Dmitry Smirnov used all available fire extinguishers on site, but even after the extinguishers were exhausted and the power cut, the fire was still not out.

"We put out the rest by putting water on the flames," Orenstein recalled.

The four-person crew was barely able to deal with the emergency, he added.

"Six or seven [people], to me, seems realistic as the adequate number of people to handle a situation like this most effectively."

The middle of the greenhouse, which was called the GreenHab, was destroyed. An investigation by the fire marshal determined two days later that an electrical heater caused the fire, which was ruled an accident.

The heater was set up close to some wooden shelves that had likely dried out over more than 10 years of use, said Orenstein, who is also the volunteer MDRS GreenHab coordinator.

Damage inside the Mars Desert Research Station GreenHab following a fire on Dec. 29, 2014. 

Credit: Nick Orenstein

In response to a 911 call, the Lane County sheriff came to MDRS later on Dec. 29, after the crew had successfully fought the fire.

NB: The isolated location of the facility means it usually takes some time for emergency services to arrive.

The sheriff did a preliminary investigation and confirmed that nobody was hurt, Orenstein said.

Orenstein's crew, the 146th one to use the habitat, decided it was best to stay in Hanksville temporarily, for two reasons, there were no fire extinguishers left at the research station, and there was some concern about chemical contamination in the habitat from the fire.

"My responsibilities for the next few days were to look after the crew and to make sure that they were OK," Orenstein said.

"Essentially, it was a post-tramautic stress therapy session there. We were making sure we were all OK, and looking out for each other."

MDRS director Shannon Rupert and a few other MDRS officials did extra cleanup before the next crew arrived, and Orenstein went back to the facility briefly for the Crew 147 handover later in January.

A temporary tentlike greenhouse is now available for experiments to go forward this season, Rupert added.

"It's devastating because it's a loss of a functional component of the campus," Rupert told reporters.

"But it could have been so much worse. Everyone was safe. That was the main thing. Everybody got out."

ESA Rosetta Mission: COSIMA collects and analyses Comet 67/P Dust Particles

Two examples of dust grains collected by ESA Rosetta's COmetary Secondary Ion Mass Analyser, (COSIMA) instrument in the period 25-31 October 2014. 

Both grains were collected at a distance of 10-20 km from the comet nucleus. 

Image (a) shows a dust particle (named by the COSIMA team as Eloi) that crumbled into a rubble pile when collected; (b) shows a dust particle that shattered (named Arvid). 

For both grains, the image is shown twice under two different grazing illumination conditions: the top image is illuminated from the right, the bottom image from the left. 

The brightness is adjusted to emphasise the shadows, in order to determine the height of the dust grain. Eloi therefore reaches about 0.1 mm above the target plate; Arvid about 0.06 mm. 

The two small grains at the far right of image (b) are not part of the shattered cluster. The fact that the grains broke apart so easily means their individual parts are not well glued together. 

If they contained ice they would not shatter; instead, the icy component would evaporate off the grain shortly after touching the collecting plate, leaving voids in what remained. 

By comparison, if a pure water-ice grain had struck the detector, then only a dark patch would have been seen. 

These 'fluffy' grains are thought to originate from the dusty layer built up on the comet's surface since its last close approach to the Sun, and will soon be lost into the coma. 

Image courtesy ESA /Rosetta et al

ESA's Rosetta mission is providing unique insight into the life cycle of a comet's dusty surface, watching 67P/Churyumov-Gerasimenko as it sheds the dusty coat it has accumulated over the past four years.

The COmetary Secondary Ion Mass Analyser, (COSIMA), is one of Rosetta's three dust analysis experiments. It started collecting, imaging and measuring the composition of dust particles shortly after the spacecraft arrived at the comet in August 2014.

Results from the first analysis of its data are reported in the journal Nature. "Comet 67P/Churyumov-Gerasimenko sheds dust coat accumulated over the past four years" - Rita Schulz et al. Nature (2015) doi:10.1038/nature14159

The study covers August to October, when the comet moved along its orbit between about 535 million kilometres to 450 million kilometres from the Sun. Rosetta spent the most of this time orbiting the comet at distances of 30 km or less.

The scientists looked at the way that many large dust grains broke apart when they were collected on the instrument's target plate, typically at low speeds of 1-10 m/s.

The grains, which were originally at least 0.05 mm across, fragmented or shattered upon collection.

The fact that they broke apart so easily means that the individual parts were not well bound together. Moreover, if they had contained ice, they would not have shattered.

Instead, the icy component would have evaporated off the grain shortly after touching the collecting plate, leaving voids in what remained.

By comparison, if a pure water-ice grain had struck the detector, then only a dark patch would have been seen.

The dust particles were found to be rich in sodium, sharing the characteristics of 'interplanetary dust particles'.

These are found in meteor streams originating from comets, including the annual Perseids from Comet 109P/Swift-Tuttle and the Leonids from 55P/Tempel-Tuttle.

"We found that the dust particles released first when the comet started to become active again are 'fluffy'.

They don't contain ice, but they do contain a lot of sodium. We have found the parent material of interplanetary dust particles," says lead author Rita Schulz of ESA's Scientific Support Office.

The scientists believe that the grains detected were stranded on the comet's surface after its last perihelion passage, when the flow of gas away from the surface had subsided and was no longer sufficient to lift dust grains from the surface.

While the dust was confined to the surface, the gas continued evaporating at a very low level, coming from ever deeper below the surface during the years that the comet travelled furthest from the Sun.

Effectively, the comet nucleus was 'drying out' on the surface and just below it.

"We believe that these 'fluffy' grains collected by Rosetta originated from the dusty layer built up on the comet's surface since its last close approach to the Sun," explains Martin Hilchenbach, COSIMA principal investigator at the Max-Planck Institute for Solar System research in Germany.

"This layer is being removed as the activity of the comet is increasing again. We see this layer being removed, and we expect it to evolve into a more ice-rich phase in the coming months."

The comet is on a 6.5-year circuit around the Sun, and is moving towards its closest approach in August of this year.

At that point, Rosetta and the comet will be 186 million kilometres from the Sun, between the orbits of Earth and Mars.

As the comet warms, the outflow of gases is increasing and the grains making up the dry surface layers are being lifted into the inner atmosphere, or coma.

Eventually, the incoming solar energy will be high enough to remove all of this old dust, leaving fresher material exposed at the surface.

"In fact, much of the comet's dust mantle should actually be lost by now, and we will soon be looking at grains with very different properties," says Rita.

"Rosetta's dust observations close to the comet nucleus are crucial in helping us to link together what is happening at the very small scale with what we see at much larger scales, as dust is lost into the comet's coma and tail," says Matt Taylor, ESA's Rosetta project scientist.

"For these observations, it really is a case of "watch this space" as we continue to watch in real time how the comet evolves as it approaches the Sun along its orbit over the coming months."

Tuesday, January 27, 2015

ESA Rosetta: Fissure spanning 100 metres discovered on Comet 67/P

A fissure spanning over 100 meters across the neck of Rosetta’s comet 67P raises the question of if, or when, the comet will break up. 

The fissure is part of released studies by Rosetta scientists in the journal Science. 

Credit: ESA/Rosetta, Illustration, T.Reyes

Not all comets break up as they vent and age, but for ESA Rosetta's comet 67P, the Rubber Duckie comet, a crack in the neck raises concerns.

Some comets may just fizzle and uniformly expel their volatiles throughout their surfaces. They may become like puffballs, shrink some but remain intact.

Comet 67P is the other extreme. The expulsion of volatile material has led to a shape and a point of no return; it is destined to break in two.

The fissure is part of the analysis in a new set of science papers published this week.

The images show a fissure spanning a few hundred meters across the neck of the two lobe comet.

The fissure is just one of the many incredible features on Comet 67P and is reported in research articles released in the January 22, 2015, edition of the journal Science.

Left: A map looking at the northern (right-hand rule, positive,) pole of 67P showing the total energy received from the Sun per rotation on 6 August 2014. 

The base of the neck (Hapi) receives ~15% less energy than the most illuminated region, 3.5 × 106 J m-2 (per rotation). 

If self-heating were not included, the base of the neck would receive ~30% less total energy. 

Right: Similar to the left panel but showing total energy received over an entire orbital period in J m-2 (per orbit). 


What it means is not certain, but Rosetta team scientists have stated that flexing of the comet might be causing the fissure.

As the comet approaches the Sun, the solar radiation is raising the temperature of the surface material.

Like all materials, the comet's will expand and contract with temperature. And diurnal (daily) changes in the tidal forces from the Sun is a factor, too.'

The crack, or fissure, could spell the beginning of the end for comet 67P/Churyumov–Gerasimenko. It is located in the neck area, in the region named Hapi, between the two lobes that make 67P appear so much like a Rubber Duck from a distance.

The fissure could represent a focal point of many properties and forces at work, such as the rotation rate and axis – basically head over heels of the comet.

The fissure lies in the most active area at present, and possibly the most active area overall.

Though the Hapi region appears to receive nearly constant sunlight, at this time, Rosetta measurements (below) show otherwise – receiving 15% less sunlight than elsewhere.

Top left: The Hathor cliff face is to the right in this view. The aligned linear structures can be clearly seen. 

The smooth Hapi region is seen at the base of the Hathor cliff. Boulders are prevalent along the long axis of the Hapi region. 

Bottom left and right: Crack in the Hapi region. 

The left panel shows the crack (indicated by red arrows) extending across Hapi and beyond. 

The right panel shows the crack where it has left Hapi and is extending into Anuket, with Seth at the uppermost left and Hapi in the lower left. 

Credit: ESA/Rosetta

Sunlight and heating are major factors and the neck likely experiences the greatest mechanical stresses, internal torques, from heating or tidal forces from the sun as it rotates and approaches perihelion.

Rosetta scientists are still not certain whether 67P is two bodies in contact, a contact binary, or a shape that formed from material expelled about the neck area leading to its narrowing.

The Philae lander's MUPUS thermal sensor measured a temperature of –153°C (–243°F) at the landing site, while VIRTIS, an instrument on the primary spacecraft Rosetta, has measured -70°C (-94°F) at present.

These temperatures will rise as perihelion is reached on August 13, 2015, at a distance of 1.2432 A.U. (24% further from the Sun than Earth). At present – January 23rd – 67P is 2.486 A.U. from the Sun (2 1/2 times farther from the Sun than Earth).

While not a close approach to the Sun for a comet, the Solar radiation intensity will increase by 4 times between the present (January 2014) and perihelion in August.

Stresses due to temperature changes from diurnal variations, the changing Sun angle during perihelion approach, from loss of material, and finally from changes in the tidal forces on a daily basis (12.4043 hours) may lead to changes in the fissure causing it to possibly widen or increase in length.

Rosetta will continue escorting the comet and delivering images of the whole surface that will give Rosetta scientists the observations and measurements to determine 67P/Churyumov–Gerasimenko's condition now and its fate in the longer term.

Read the full article here

Mexico Volcano of Fire eruption caught on camera - Video

Dramatic video caught on webcam showed eruptions with clouds of smoke rising above the crater of the Volcan del Fuego (Volcano of Fire), set between the states of Colima and Jalisco.

Three separate bursts were seen on Wednesday (January 21), Sunday (January 25) with a nocturnal one on Monday (January 26). Webcams de captured the dramatic images.

The 9,939-feet above sea-level (3,860-meters) Volcan del Fuego, one of Mexico's most active, has frequent moderate explosions.

Activity at the volcano was also reported in January.

Canadian Space Technology to Help Sick Children

Surgeons would have us believe that nothing rivals the dexterity of a good surgeon's hands, but humans being humans, fatigue or even tremors after a long day at the hospital can make things challenging, especially when operating on small children.

That is why Toronto's SickKids Centre for Image-Guided Innovation & Therapeutic Intervention (CIGITI) turned to the Canadian space technology behind Canadarm, Canadarm2 and Dextre and partnered with MacDonald, Dettwiler and Associates Ltd. (MDA) to develop KidsArm.

KidsArm platform with biopsy tool attached.

Image Credit: MDA and CIGITI

The third prototype of KidsArm, the first image-guided robotic surgical arm in the world specifically designed for pediatric surgery, is currently being tested at SickKids Hospital, and researchers are hoping that the technology might soon lend a helping hand to surgeons around the country.

While more testing is needed, the robot is also promising for fetal, cardiac, neurological and urological surgeries.

The suturing tool demonstrates image-guided anastomosis, which means the connecting of parts such as vessels. 

The target on the top of the tool is used to lead the tool's tip. 

This is the same technology used to track the robotic systems on the space shuttle and the International Space Station.

Image Credit: MDA and CIGITI

Using a pair of hand controllers in conjunction with high-precision, real-time imaging technology, surgeons can pinpoint the area of concern to make it easier to reconnect delicate vessels, for example.

KidsArm is also equipped with miniaturized dexterous tools that can cut, coagulate, apply suction, or use a laser.

It is capable of working 10 times faster and with more accuracy than a surgeon's hands when performing intricate procedures.

Advanced technologies such as imaged-based tissue tracking and robotic assistance select and track sutures so that surgeons can compensate for the tissue motion that sometimes makes these surgeries difficult.

A stereo camera generates a 3D point cloud, a set of data points that guide the tool tip and apply a series of sutures. KidsArm pushes the envelope using advanced imaging to identify suture locations.

This allows the surgeon to automate the suturing of small vessels and other microsurgical tasks.

The precision required by KidsArm has to be at least 10 times better than what DEXTRE is able to achieve.

To face this technical challenge, the MDA team adopted the virtual decomposition control (VDC) approach developed by Canadian Space Agency (CSA) engineer Wen-Hong Zhu.

Wen-Hong Zhu
Thanks to this technology, KidsArm is capable of performing intricate procedures such as the suturing of blood vessels and tissues 10 times faster and with more accuracy than a surgeon's hands.

The VDC is a Canadian game-changing technology for precision control of future medical manipulators and space manipulators.

In terms of robotics, the team used a combination of industrial robots, control electronics, cameras and haptics (force-feedback controllers).

The control software evolved directly from the Dextre and Canadarm programs at MDA, and the vision was adapted from their satellite navigation work for the CSA.

One day, this technology may help by making medical procedures on children less invasive and less painful, allowing them to return home faster... so that kids can be kids.

Monday, January 26, 2015

Asteroid 2004 BL86: NEO That Flew Past Earth Has A Companion Moon - Binary

This movie of asteroid 2004 BL86 was generated from data collected by NASA's Deep Space Network antenna at Goldstone, California, on Jan. 26, 2015. Twenty individual images were used.

Credit: NASA

Scientists working with NASA's 230-foot-wide (70-meter) Deep Space Network antenna at Goldstone, California, have released the first radar images of asteroid 2004 BL86.

The images show the asteroid, which made its closest approach on Jan. 26, 2015 at 8:19 a.m. PST (11:19 a.m. EST) at a distance of about 745,000 miles (1.2 million kilometers, or 3.1 times the distance from Earth to the moon), has its own small moon.

The 20 individual images used in the movie were generated from data collected at Goldstone on Jan. 26, 2015.

They show the primary body is approximately 1,100 feet (325 meters) across and has a small moon approximately 230 feet (70 meters) across.

In the near-Earth population, about 16 percent of asteroids that are about 655 feet (200 meters) or larger are a binary (the primary asteroid with a smaller asteroid moon orbiting it) or even triple systems (two moons).

The resolution on the radar images is 13 feet (4 meters) per pixel.

The trajectory of asteroid 2004 BL86 is well understood. Monday's flyby was the closest approach the asteroid will make to Earth for at least the next two centuries.

It is also the closest a known asteroid this size will come to Earth until asteroid 1999 AN10 flies past our planet in 2027.

Asteroid 2004 BL86 was discovered on Jan. 30, 2004, by the Lincoln Near-Earth Asteroid Research (LINEAR) survey in White Sands, New Mexico.

Radar is a powerful technique for studying an asteroid's size, shape, rotation state, surface features and surface roughness, and for improving the calculation of asteroid orbits.

Radar measurements of asteroid distances and velocities often enable computation of asteroid orbits much further into the future than if radar observations weren't available.

NASA places a high priority on tracking asteroids in a vain effort that this will somehow protect our home planet from them.

In fact, the U.S. believes it has the most robust and productive survey and detection program for discovering near-Earth objects (NEOs), and report that to date, taking into account all U.S. assets, both civil and military, they have discovered over 98 percent of the known NEOs.

NASA Galileo Image: Jupiter’s cratered moon, Callisto

The speckled object depicted here is Callisto, Jupiter’s second largest moon. 

This image was taken in May 2001 by NASA’s Galileo spacecraft, which studied Jupiter and its moons from 1995 until 2003.

Similar in appearance to a golf ball, Callisto is covered almost uniformly with pockmarks and craters across its surface, evidence of relentless collisions.

In fact, Callisto is the most heavily cratered object in the Solar System.

The moon is made up of equal parts of rock and ice, the brighter parts of Callisto’s surface are thought to be mainly water ice, whereas the darker patches are regions of highly eroded and ice-poor rocky material.

Callisto is roughly the same size as the planet Mercury, but only about a third of the mass. It is the outermost of Jupiter’s four large Galilean satellites, a group consisting of Io, Europa, Ganymede and Callisto.

It orbits relatively far away from Jupiter compared to these other satellites: it lies 1 880 000 km from the planet, roughly 26 times the radius of the planet itself.

While this in itself is not unusual, our Moon orbits at some 60 times Earth’s radius, the important thing is Callisto’s isolation from its neighbouring moons.

Callisto’s closest neighbour is Ganymede, which orbits 800 000 km closer to Jupiter.

This isolation means that Callisto does not experience any significant tidal forces from Jupiter that would tear at its structure.

It also does not show any signs of geological processes such as volcanism or plate tectonics, which we clearly see on moons that are involved in violent cosmic tugs-of-war with Jupiter, such as Io, Europa and Ganymede.

Callisto remains relatively intact and is a witness of the early Solar System: its surface is the oldest terrain, at a truly ancient four billion years.

This image is the only complete full-colour view of Callisto obtained by Galileo.

The spacecraft provided us with a great deal of information about the jovian system: as well as sending the first probe into the atmosphere of Jupiter, and measuring Jupiter’s composition and dynamics, it observed Io’s volcanism, sent back data supporting the idea of a liquid ocean on Europa, and probed the properties of Ganymede and the subject of this image,

Callisto. It also managed to observe the famous Comet Shoemaker–Levy 9 colliding with Jupiter in 1994.

The jovian system will be visited again in the not-too-distant future. In 2016, NASA’s Juno spacecraft will arrive at Jupiter and start to beam back images of the planet’s poles.

Later, ESA’s Juice, short for JUpiter ICy moons Explorer, planned for launch in 2022, will tour the system with the aim of making a breakthrough in our knowledge of the giant gaseous planet and its environs, especially the intriguing moons Ganymede, Europa and Callisto.

Sunday, January 25, 2015

Scottish Scientists Slow down Light Particles - Photons

The speed of light is a limit, not a constant, that's what researchers in Glasgow, Scotland, say. A group of them just proved that light can be slowed down, permanently.

Scientists already knew light could be slowed temporarily. Photons change speeds as they pass through glass or water, but when they exit the other side and return to a vacuum (like outer space) they speed back up.

In a new experiment at the University of Glasgow, however, scientists were able to permanently manipulate light's speed by passing photons through a device that alters their structure. The device, created in collaboration with researchers at Heriot-Watt University in Edinburgh, is a filter of sorts that the scientists refer to as a mask.

"That mask looks a little bit like a bull's-eye target," researcher Miles Padgett told reporters. "And that mask patterns the light beam, and we show that it's the patterning of the light beam that slows it down.

"But once that pattern has been imposed, even now the light is no longer in the mask, it's just propagating in free space, the speed is still slow," Padgett added.

In other words, the beam of light is reorganized in a way that slows down each individual photon. When tested in a vacuum next to a regular light beam.

Photons that had been filtered through mask were milliseconds behind in a sprint to the end of the vacuum racetrack.

Researchers, whose latest work was published this week in the journal Science Express, say the findings prove the speed of light is not an absolute, more like a ceiling.

Miles Padgett
The work was carried out by a team from the University of Glasgow’s Optics Group, led by Professor Miles Padgett, working with theoretical physicists led by Stephen Barnett, in partnership with Professor Daniele Faccio from Heriot-Watt’s Institute of Photonics and Quantum Sciences.

Daniele Faccio
Professor Faccio said, “The speed of light is a universal constant and plays a central role in our understanding of the Universe and Einstein's theory of relativity."

"The exciting discovery here is that this speed is the true speed of light only for plane waves, that is waves that are perfectly flat."

"In everyday situations however, we interact with light that is not a plane wave but has some kind of structure on it."

"The presence of this structure (think of the light beam emitted from a laser pointer) forces the light to actually move slower."

"There are lots of technicalities involved in the actual experiments used to measure this slow-down, but the result is widely applicable. A very appropriate discovery for the 2015 international year of light".

Professor Padgett added, “It might seem surprising that light can be made to travel more slowly like this, but the effect has a solid theoretical foundation and we’re confident that our observations are correct.

“The results give us a new way to think about the properties of light and we’re keen to continue exploring the potential of this discovery in future applications."

"We expect that the effect will be applicable to any wave theory, so a similar slowing could well be created in sound waves, for example.”

More Information
Spatially structured photons that travel in free space slower than the speed of light - Science Magazine January 22 2015 - Science DOI: 10.1126/science.aaa3035

NASA DAWN: Mysterious Bright Spot on Dwarf Planet Ceres

A mysterious white spot can be seen in the newest images from NASA's Dawn spacecraft, which is rapidly approaching the dwarf planet. 

Credit: NASA /JPL-Caltech /UCLA /MPS /DLR /IDA /PSI

A strange, flickering white blotch found on the dwarf planet Ceres by NASA's Dawn spacecraft has scientists scratching their heads.

The white spot on Ceres in a series of new photos taken on Jan. 13 by NASA's Dawn spacecraft, which is rapidly approaching the round dwarf planet in the asteroid belt between the orbits of Mars and Jupiter, but when the initial photo release on Monday (Jan. 19), the Dawn scientists gave no indication of what the white dot might be.

"Yes, we can confirm that it is something on Ceres that reflects more sunlight, but what that is remains a mystery," Marc Rayman, mission director and chief engineer for the Dawn mission, told in an email.

The new images show areas of light and dark on the face of Ceres, which indicate surface features like craters, but at the moment, none of the specific features can be resolved, including the white spot.

"We do not know what the white spot is, but it's certainly intriguing," Rayman said. "In fact, it makes you want to send a spacecraft there to find out, and of course that is exactly what we are doing! So as Dawn brings Ceres into sharper focus, we will be able to see with exquisite detail what [the white spot] is."

Ceres is a unique object in our solar system. It is the largest object in the asteroid belt and is classified as an asteroid. It is simultaneously classified as a dwarf planet, and at 590 miles across (950 kilometers, or about the size of Texas), Ceres is the smallest known dwarf planet in the solar system.

The $466 million Dawn spacecraft is set to enter into orbit around Ceres on March 6. Dawn left Earth in 2007 and in the summer of 2011, it made a year-long pit stop at the asteroid Vesta, the second largest object in the asteroid belt.

Friday, January 23, 2015

ESA Rosetta Comet 67/P Mission: Rosetta Team Uncovers More Secrets

A colour image of Comet 67P/Churyumov-Gerasimenko composed of three images taken by Rosetta’s scientific imaging system OSIRIS in the red, green and blue filters; the images were taken on August 6, 2014 from a distance of 120 km from the comet. 

Image credit: ESA / Rosetta / MPS / OSIRIS Team / UPD /LAM / IAA / SSO / INTA / UPM / DASP / IDA.

The familiar shape of the comet has now had many of its vital statistics measured: the small lobe measures 2.6 × 2.3 × 1.8 km and the large lobe 4.1 × 3.3 × 1.8 km.

The total volume of the comet is 21.4 km3. Rosetta’s Radio Science Instrument has measured its mass to be 10 billion tons, yielding a density of 470 kg/m3.

By assuming an overall composition dominated by water ice and dust with a density of 1,500–2,000 kg/m3, Rosetta scientists show that the comet has a very high porosity of 70–80 percent, with the interior structure likely comprising weakly bonded ice-dust clumps with small void spaces between them.

The OSIRIS instrument has imaged some 70 percent of the surface to date: the remaining unseen area lies in the southern hemisphere that has not yet been fully illuminated since Rosetta’s arrival.

The scientists have so far identified 19 regions separated by distinct boundaries and, following the ancient Egyptian theme of the Rosetta mission, these regions are named for Egyptian deities, and are grouped according to the type of terrain dominant within.

The 19 regions identified on 67P/Churyumov–Gerasimenko are separated by distinct geomorphological boundaries; they are grouped according to the type of terrain dominant within each region. 

Five basic categories of terrain type have been determined: dust-covered (Ma’at, Ash and Babi); brittle materials with pits and circular structures (Seth); large-scale depressions (Hatmehit, Nut and Aten); smooth terrains (Hapi, Imhotep and Anubis), and exposed, more consolidated surfaces (Maftet, Bastet, Serqet, Hathor, Anuket, Khepry, Aker, Atum and Apis). 

Image credit: ESA / Rosetta / MPS / OSIRIS Team / UPD /LAM / IAA / SSO / INTA / UPM / DASP / IDA.

Five basic, but diverse, categories of terrain type have been determined: dust-covered; brittle materials with pits and circular structures; large-scale depressions; smooth terrains; and exposed more consolidated surfaces.

Much of the northern hemisphere is covered in dust. As the comet is heated, ice turns directly into gas that escapes to form the atmosphere or coma.

Dust is dragged along with the gas at slower speeds, and particles that are not traveling fast enough to overcome the weak gravity fall back to the surface instead.

Some sources of discrete jets of activity have also been identified. While a significant proportion of activity emanates from the smooth neck region, jets have also been spotted rising from pits.

The gases that escape from the surface have also been seen to play an important role in transporting dust across the surface, producing dune-like ripples, and boulders with ‘wind-tails,’ the boulders act as natural obstacles to the direction of the gas flow, creating streaks of material ‘downwind’ of them.

“Because comets have very little gravity, dust and gas flow freely into space. But we were surprised to find a cloud of particles orbiting the comet that are large and heavy enough to defy the Sun’s radiation pressure,” said Dr Dennis Bodewits of the University of Maryland.

The scientists were able to make this discovery thanks to OSIRIS’ very sensitive cameras.

“Each pixel is about 30 cm. You couldn’t see a coffee cup, but you could see a large lunchbox. The resolution is about 10 times higher than Google Earth.”

According to the team, 67P/Churyumov-Gerasimenko was releasing the earthly equivalent of 1.2 liters of water into space every second at the end of August 2014.

MIRO (Microwave Instrument for the Rosetta Orbiter)

Credit: ESA

“In observations, made by the Microwave Instrument for Rosetta Orbiter (MIRO), over a period of three months, the amount of water in vapor form that the comet was dumping into space grew about tenfold,” said Dr Sam Gulkis of NASA’s Jet Propulsion Laboratory in Pasadena.

“To be up close and personal with a comet for an extended period of time has provided us with an unprecedented opportunity to see how comets transform from cold, icy bodies to active objects spewing out gas and dust as they get closer to the Sun.”

Thursday, January 22, 2015

ESA Rosetta Mission: Sneak peek at Comet 67/P's "underside" - Cheops

ESA Rosetta NavCam captures a four-image mosaic of 67P/Churyumov-Gerasimenko on Jan. 16, 2015. 

Credit: ESA/Rosetta /NAVCAM – CC BY-SA IGO 3.0

A particularly dramatic view of comet 67P/C-G due to the angle of solar illumination, this is a mosaic made from four images acquired by ESA Rosetta's NavCam on January 16, 2015, from a distance of 28.4 km (17.6 miles).

The assembled image shows the larger "bottom" lobe of comet 67/P, with a flat region called Imhotep along the left side and, on the lower right, the transition area stretching up to the comet's smaller "head" lobe.

Outgassing jets can be seen as faint streaks at the upper right, and ejected dust grains show up as bright specks above its surface.

Also in this view is one of 67P's larger boulders, a somewhat pyramid-shaped rock dubbed "Cheops."

Position of the Cheops boulder on 67P 

Credit: ESA /Rosetta /Navcam

One in a cluster of boulders on 67P's "underside," Cheops is about 45 meters wide and 25 meters high (148 x 82 feet).

When it was first observed in Rosetta images Cheops and the nearby cluster reminded scientists of the pyramids at Giza in Egypt, and so it was named for the largest of those pyramids, the Great Pyramid, a tomb for the pharaoh Cheops (the Hellenised name for Khufu) built around 2,550 BCE.

Scientists are still working to determine the nature of 67P's boulders. It's not yet known what they are made of or how they came to be where they are observed today.

Did they fall into their current positions? Or were they exposed upwards from below as a result of the comet's activity? And why do they have alternating rough and smooth areas on their surfaces?

"It almost looks as if loose dust covering the surface of the comet has settled in the boulder's cracks, but, of course, it is much too early to be sure," said OSIRIS Principal Investigator Holger Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany.

As comet 67P approaches perihelion over the course of the next six months we will get to see firsthand via Rosetta what sorts of changes occur to its surface features, including office-building-sized boulders like Cheops.

OSIRIS image of Cheops acquired on Sept. 19, 2014. 


ESA’s Intermediate eXperimental Vehicle (IXV) has been fueled and “topped off”

The loading of IXV (Intermediate eXperimental Vehicle)’s hydrazine maneuvering propellant was performed inside the S5B hall at Europe’s Spaceport in French Guiana.

Credit: Arianespace, ESA

ESA’s IXV (Intermediate eXperimental Vehicle) has been “topped off” at the Spaceport in French Guiana as preparations continue for its launch with Vega’s year-opening mission on February 11.

Loading of IXV’s hydrazine maneuvering propellant was performed in the S5B hall of the Spaceport’s large S5 payload preparation facility.

Thales Alenia Space engineers working on the IXV.

Credit: Thales Alenia Space, ESA

IXV (Intermediate eXperimental Vehicle) was built for the European Space Agency (ESA) by Thales Alenia Space, and is designed to flight test technologies and critical systems for Europe’s future automated reentry systems as they return from low Earth orbit.

Artist impression of ESA's Intermediate eXperimental Vehicle (IXV).

Credit: ESA

The unmanned IXV is to be deployed into a suborbital trajectory by Vega at a 320-km. altitude.

After IXV coasts up to an altitude of 420 km., it will begin the reentry phase, recording data from a large number of conventional and advanced sensors.

The IXV Intermediate eXperimental Vehicle is being prepared for launch at Europe's Spaceport in Kourou, French Guiana.

Credit: ESA

The entry speed of 7.5 km. per second creates the same conditions as those for a vehicle returning from low Earth orbit, with IXV subsequently descending via parachutes for a safe splashdown in the Pacific Ocean approximately 100 minutes after liftoff.

Vega’s February 11 mission will mark the lightweight launcher’s second flight within the European Space Agency-managed VERTA (Vega Research and Technology Accompaniment) program to showcase this vehicle's flexibility.

The industrial prime contractor for Vega is ELV S.p.A., a company created by Avio and the Italian Space Agency (ASI) in December 2000.

Engineers forging ahead with the final tests on ESA’s Intermediate eXperimental Vehicle, IXV.

Credit: ESA

The IXV (Intermediate eXperimental Vehicle) is being prepared for launch at Europe's Spaceport in Kourou, French Guiana.

IXV will be launched 320 km into space on top of a Vega  rocket, climbing up to 420 km before beginning a long glide back through the atmosphere.

In the process, IXV will gather data on reentry conditions to help guide the design of future spaceplanes. 

Wednesday, January 21, 2015

Meteorologists investigate Airborne jet streams bringing both floods and drought relief

A satellite image showing water-vapour concentration reveals an atmospheric river (yellow) streaming northeast across the Pacific Ocean.

Californians call it the Pineapple Express: a weather pattern that zips across the Pacific Ocean from Hawaii, delivering not baskets of tropical fruit, but buckets of rain and snow.

In meteorological terms, the Pineapple Express is an atmospheric river, a narrow band of air that carries huge amounts of moisture.

For the next six weeks, meteorologists will be plying the eastern Pacific by air and sea, in the hope of catching several atmospheric rivers barrelling towards the coast.

It is the biggest push yet to understand these phenomena, which have received serious scientific attention only in the past decade.

Atmospheric rivers get their start over warm tropical waters; they then flow eastwards and towards the poles a kilometre or two above the ocean surface.

They may stretch for thousands of kilometres, but are only a few hundred kilometres wide. When they hit land, they start to drop their moisture in torrential downpours or blizzards.

“When we have too many atmospheric rivers, floods can occur, and when we don’t have enough we gradually fall into drought,” says Marty Ralph, a meteorologist at the Scripps Institution of Oceanography in La Jolla, California, and a leader of the field campaign.

In Europe, atmospheric rivers affect mostly the western part of the continent, but they can be felt as far inland as Poland.

In North America, the entire west coast is affected, and parts of the central and eastern United States occasionally feel the effects of atmospheric rivers that develop over the Gulf of Mexico.

The moisture is often welcome, bringing up to half of the year’s water supply in affected areas1.

A 2013 study found that as many as three-quarters of all droughts in the Pacific Northwest between 1950 and 2010 had been brought to an end by atmospheric-river storms2.

California has been stricken by drought for years (Nature 512, 121–122; 2014), but last month, an atmospheric river dropped enough rain to erase one-third of the water deficit of one major reservoir in just two days.

Climate change may bring stronger and more frequent atmospheric rivers, because the warmer the atmosphere is, the more water it can hold, says David Lavers, a meteorologist at Scripps who is not involved in the project.

“The more you know about how the atmosphere behaves,” he says, “the better position you’re in to prepare for extreme events.”

Read the full article on Nature website - Nature 517, 424–425 (22 January 2015) doi:10.1038/517424a

Tuesday, January 20, 2015

NASA SDO: Sun Monitoring Satellite captures 100 millionth image

The Atmospheric Imaging Assembly on NASA's Solar Dynamics Observatory captured its 100 millionth image of the sun on Jan. 19, 2015. 

The dark areas at the bottom and the top of the image are coronal holes, areas of less dense gas, where solar material has flowed away from the sun. 


On Jan. 19, 2015, at 12:49 p.m. EST, an instrument on NASA's Solar Dynamics Observatory captured its 100 millionth image of the sun.

The instrument is the Atmospheric Imaging Assembly (AIA), which uses four telescopes working parallel to gather eight images of the sun, cycling through 10 different wavelengths -- every 12 seconds.

The Atmospheric Imaging Assembly (AIAimages the solar atmosphere in multiple wavelengths to link changes in the surface to interior changes. 

Data includes images of the Sun in 10 wavelengths every 10 seconds. 

Credit: NASA SDO, Lockheed Martin Solar Astrophysics Laboratory

The Helioseismic and Magnetic Imager extends the capabilities of the SOHO/MDI instrument with continual full-disk coverage at higher spatial resolution and new vector magnetogram capabilities.

Credit: NASA SDO, Lockheed Martin Solar Astrophysics Laboratory

Between the AIA and two other instruments on board, the Helioseismic Magnetic Imager (HMI) and the Extreme Ultraviolet Variability Experiment (EVE), SDO sends down a whopping 1.5 terabytes of data a day.

The Extreme Ultraviolet Variability Experiment measures the solar extreme-ultraviolet (EUV) irradiance with unprecedented spectral resolution, temporal cadence, and precision. 

EVE measures the solar extreme ultraviolet (EUV) spectral irradiance to understand variations on the timescales which influence Earth's climate and near-Earth space.

Credit: NASA SDO, Lockheed Martin Solar Astrophysics Laboratory

AIA is responsible for about half of that. Every day it provides 57,600 detailed images of the sun that show the dance of how solar material sways and sometimes erupts in the solar atmosphere, the corona.

In the almost five years since its launch on Feb. 11, 2010, SDO has provided images of the sun to help scientists better understand how the roiling corona gets to temperatures some 1000 times hotter than the sun's surface, what causes giant eruptions such as solar flares, and why the sun's magnetic fields are constantly on the move.