Mars Spacecraft reveal comet flyby effects on Martian atmosphere

Two NASA and one European spacecraft, including NASA's MAVEN mission led by the University of Colorado Boulder, have gathered new information about the basic properties of a wayward comet that buzzed by Mars Oct. 19, directly detecting its effects on the Martian atmosphere.

Data from observations carried out by MAVEN, NASA's Mars Reconnaissance Orbiter (MRO) and the ESA's Mars Express spacecraft revealed that debris from the comet, known officially as Comet C/2013 A1 Siding Spring, caused an intense meteor shower and added a new layer of ions, or charged particles, to the ionosphere.

The ionosphere is an electrically charged region in the atmosphere that reaches from about 75 miles (120 kilometers) to several hundred miles above the Martian surface.

ESA's Mars Express spacecraft

Using the observations, scientists were able to make a direct connection between the input of debris from the meteor shower to the subsequent formation of the transient layer of ions, the first time such an event has been observed on any planet, including Earth, said the MAVEN research team.

The comet traveled from the most distant region of our solar system called the Oort Cloud and made a close approach at 2:27 p.m. EDT within about 87,000 miles (139,500 kilometers) of the Red Planet.

That is less than half the distance between Earth and our moon and less than one-tenth the distance of any known comet flyby of Earth.

"MAVEN is well suited for studying the effects of the dust from the comet in the Martian atmosphere, because it makes measurements at the altitudes where the dust was expected to have an effect," said CU-Boulder Professor Bruce Jakosky of the Laboratory for Atmospheric and Space Physics, the principal investigator on the $671 million Mars Atmosphere and Volatile EvolutioN (MAVEN) mission.

"We also should be able to see if there are long-term effects from the comet dust in that same region of the atmosphere."

The places where the red line on this graph extends higher than the blue line show detection of metals added to the Martian atmosphere from dust particles released by a passing comet. 

The graphed data are from the Imaging Ultraviolet Spectrograph (IUVS) on NASA's MAVEN spacecraft, which recorded the intensities of emission by ingredients in the Martian atmosphere just before (blue line) and after (red line) comet C/2013 A1 Siding Spring sped within about 87,000 miles (139,500 kilometers) of Mars on Oct. 19, 2014. 

The "before" line records the usual main gases in the atmosphere, primarily carbon dioxide and its byproducts.

The "after" line includes those plus peaks at 280 nanometer wavelength, a fingerprint of ionized magnesium, and other wavelengths that are fingerprints of iron.

Researchers interpret this change as a result of vaporisation of dust particles that came from the comet and entered the Martian atmosphere at high speed.

Imaging Ultraviolet Spectrograph (IUVS)

IUVS uses limb scans to map the chemical makeup and vertical structure across Mars' upper atmosphere.

Dust from the comet was vaporized high in the Martian atmosphere, producing what was likely an impressive meteor shower.

The debris resulted in significant but temporary changes to the planet's upper atmosphere and possible longer-term changes.

A host of Earth-based and orbiting telescopes also observed the unique celestial event.

The MAVEN spacecraft, recently arrived at Mars, detected the comet encounter in two ways.

The remote-sensing Imaging Ultraviolet Spectrograph (IUVS) designed and built at CU-Boulder observed intense ultraviolet emissions from magnesium and iron ions high in the atmosphere in the aftermath of the meteor shower.

Not even the most intense meteor storms on Earth have produced as strong a response as this one:

The emission dominated Mars' ultraviolet spectrum for several hours after the encounter and then dissipated over the next two days, according to the MAVEN science team.

MAVEN also was able to directly sample and help scientists determine the composition of some of the vaporised comet dust in Mars' atmosphere.

Analysis of these samples by the spacecraft's Neutral Gas and Ion Mass Spectrometer (NGIMS) designed and developed at NASA Goddard Space Flight Center in Greenbelt, Maryland, detected eight different types of metal ions, including sodium, magnesium and iron.

These are the first direct measurements of the composition of dust from an Oort Cloud comet.

The Oort Cloud, well beyond the outermost planets that surround our sun, is a spherical region of icy objects believed to be material left over from the formation of the solar system.

An illustration of Maven spacecraft at Mars. Credit: NASA

"They call this comet encounter a once-in-a-lifetime event, but it's more like once-in-a-million years," said CU-Boulder Associate Professor Nick Schneider, a LASP research associate and lead IUVS scientist for the mission.

"MAVEN got there just in time, and we were ready.

The numbers suggest a Martian would have seen many thousands of shooting stars per hour, possibly enough to be called a meteor storm, so it must have been a spectacular event that night on Mars."

Elsewhere above Mars, a joint U.S. and Italian instrument on Mars Express observed a huge increase in the density of electrons in the Martian ionosphere following the comet's close approach.

"This historic event allowed us to observe the details of this fast moving Oort Cloud comet in a way never before possible using our existing Mars missions," said Jim Green, director of NASA's Planetary Science Division at the agency's headquarters in Washington.

"Observing the effects on Mars of the comet's dust slamming into the upper atmosphere makes me very happy that we decided to put our spacecraft on the other side of Mars at the peak of the dust tail passage and out of harms way."

There are three CU-Boulder undergraduates and two graduate students on the IUVS science team, said Schneider, and there will be a number of additional CU-Boulder students working on MAVEN in the coming years.

Currently there are more than 100 students working on research projects at LASP, which provides hands-on training for future careers as engineers and scientists.

NASA's Mars Exploration Rover Opportunity views comet C/2013 A1 near Mars

Researchers used the Pancam on NASA's Mars Exploration Rover Opportunity to capture this view of comet C/2013 A1 Siding Spring as it flew near Mars on Oct. 19, 2014.

Credit: NASA /JPL-Caltech /Cornell Univ. /ASU /TAMU

NASA's Mars Exploration Rover Opportunity captured images of a comet passing much closer to Mars than any previous known comet flyby of Earth or Mars.

The images of comet Siding Spring were taken against a backdrop of the pre-dawn Martian sky on Sunday (Oct. 19).

Images of comet A1 Siding Spring from the rover's panoramic camera (Pancam) are available online.

Researchers used Opportunity's Pancam to image at a range of exposure times about two-and-one-half hours before the closest approach of the nucleus of comet Siding Spring to Mars.

By the time of closest approach at about 87,000 miles (139,500 kilometers), dawn had lit the sky above Opportunity.

"It's excitingly fortunate that this comet came so close to Mars to give us a chance to study it with the instruments we're using to study Mars," said Opportunity science team member Mark Lemmon of Texas A&M University, who coordinated the camera pointing.

"The views from Mars rovers, in particular, give us a human perspective, because they are about as sensitive to light as our eyes would be."

Three NASA Mars orbiters, two Mars rovers and other assets on Earth and in space are studying comet Siding Spring.

This comet is making its first visit this close to the sun from the outer solar system's Oort Cloud, so the concerted campaign of observations may yield fresh clues to our solar system's earliest days more than 4 billion years ago.

Opportunity has been roving on Mars since January 2004 and has provided evidence about the Red Planet's ancient wet environments.

NASA's Mars Odyssey spacecraft watches comet flyby

Artist's concept of NASA's Mars Odyssey spacecraft. 

Credit: NASA/JPL-Caltech

The longest-lived robot ever sent to Mars came through its latest challenge in good health, reporting home on schedule after sheltering behind Mars from possible comet dust.

NASA's Mars Odyssey was out of communications with Earth, as planned, while conducting observations of comet C/2013 A1 Siding Spring on Sunday, Oct. 19, as the comet flew near Mars.

The comet sped within about 88,000 miles (139,500 kilometers) of Mars, equivalent to about one-third of the distance between Earth and Earth's moon.

Mars Odyssey had performed a maneuver on Aug. 5 to adjust the timing of its orbit so that it would be shielded by Mars itself during the minutes, around 1 p.m. PDT (4 p.m. EDT) today, when computer modeling projected a slight risk from high-velocity dust particles in the comet's tail.

"The telemetry received from Mars Odyssey this afternoon confirms not only that the spacecraft is in fine health but also that it conducted the planned observations of comet C/2013 A1 Siding Spring within hours of the comet's closest approach to Mars," said Odyssey Mission Manager Chris Potts of NASA's Jet Propulsion Laboratory, Pasadena, Calif., speaking from mission operations center at Lockheed Martin Space Systems, Denver.

THEMIS

Comet C/2013 A1 Siding Spring observations were made by the orbiter's Thermal Emission Imaging System (THEMIS).

Resulting images are expected in coming days after the data is downlinked to Earth and processed.

THEMIS is also scheduled to record a combined image of the comet and a portion of Mars later this week.

In addition, the Odyssey mission is using the spacecraft's Neutron Spectrometer (NS) and the Russian-made, High Energy Neutron detector (HEND) to assess possible effects on Mars' atmosphere of dust and gas from the comet.

Three NASA Mars orbiters, two Mars rovers and other assets on Earth and in space are studying comet Siding Spring.

This comet is making its first visit this close to the sun from the outer solar system's Oort Cloud, so the concerted campaign of observations may yield fresh clues to our solar system's earliest days more than 4 billion years ago.

Following the comet flyby, operations teams have also confirmed the good health of NASA's Mars Reconnaissance Orbiter and of NASA's Mars Atmosphere and Volatile EvolutioN (MAVEN) orbiter.

Mars Odyssey has worked at the Red Planet longer than any other Mars mission in history.

NASA launched the spacecraft on April 7, 2001, and Mars Odyssey arrived at Mars Oct. 24, 2001.

Besides conducting its own scientific observations, the mission provides a communication relay for robots on the Martian surface.

NASA's Mars Reconnaissance Orbiter safely watches Comet Siding Spring FlyBy

NASA's Mars Reconnaissance Orbiter, which has sent home more data about Mars than all other missions combined, is also now providing data about a comet that buzzed The Red Planet today (Oct. 19).

The orbiter continues operating in good health after sheltering behind Mars during the half hour when high-velocity dust particles from comet C/2013 A1 Siding Spring had the most chance of reaching the paths of Mars orbiters.

The Comet Siding Spring C/2013 A1 is indicated on this image as it passes Mars, seen here shining brightly on the bottom left.

Credit: Slooh

maintained radio communications with Earth throughout the comet's closest approach, at 11:27 a.m. PDT (2:27 p.m. EDT), and the peak dust-risk period centered about 100 minutes later.

"The spacecraft performed flawlessly throughout the comet flyby," said Mars Reconnaissance Orbiter Project Manager Dan Johnston of NASA's Jet Propulsion Laboratory, Pasadena, California. "It maneuvered for the planned observations of the comet and emerged unscathed."

Following the critical period of dust flux, the orbiter is communicating at 1.5 megabits per second with NASA's Deep Space Network.

It remained on Side A of its two redundant computers, and all subsystems are working as expected.

The remainder of the NASA Mars orbiters, Mars Express and ISRO's MOM, appear to be in good health and unaffected by the comet flyby.

An artist impression of the passing of Comet Siding Spring as seen by Curiosity Rover on Mars.

Credit: SLOOH

NEO Asteroid 2014 RC flyby caught on video

The NEO, asteroid 2014 RC, flew within 21,000 miles of the surface of Earth on September 7th, 2014.

A. Thirouin, B. Skiff, and N. Moskovitz analysed the brightness variations using the Lowell Observatory's 1.1m (42-inch) Hall telescope in Arizona.

NASA Messenger: Mercury Mission - 10 Years in Space

In celebration of the 10th anniversary of its launch, the MESSENGER team released this movie showing a flyover of Mercury. The movie is sped up by a factor of seven for ease of viewing.

Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory

Ten years ago, on August 3, 2004, NASA’s MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft blasted off from Cape Canaveral, Florida, for a risky mission that would take the small satellite dangerously close to Mercury’s surface, paving the way for an ambitious study of the planet closest to the Sun.

The spacecraft traveled 4.9 billion miles (7.9 billion kilometers), a journey that included 15 trips around the Sun and flybys of Earth once, Venus twice, and Mercury three times, before it was inserted into orbit around its target planet in 2011.

“We have operated successfully in orbit for more than three Earth years and more than 14 Mercury years as we celebrate this amazing 10th anniversary milestone,” said MESSENGER Mission Operations Manager Andy Calloway, of the Johns Hopkins University Applied Physics Laboratory (APL).

“The MESSENGER spacecraft operates in one of the most challenging and demanding space environments in our Solar System, and we have met that challenge directly through innovation and hard work, as exemplified by the stunning discoveries and data return achievements.

Our only regret is that we have insufficient propellant to operate another 10 years, but we look forward to the incredible science returns planned for the final eight months of the mission.”

MESSENGER captured the images in the flyover movie during this flight path over Mercury's north polar region.

Image Credit: NASA

MESSENGER is only the second spacecraft sent to Mercury. Mariner 10 flew past it three times in 1974 and 1975 and gathered detailed data on less than half the surface.

MESSENGER took advantage of an ingenious trajectory design, lightweight materials, and miniaturisation of electronics, all developed in the three decades since Mariner 10 flew past Mercury.

“It was quite challenging to design and execute a trajectory that could culminate in Mercury orbit,” said Mission and Spacecraft Systems Engineer Dan O’Shaughnessy, of APL.

“Designing an attendant spacecraft that was light enough to carry the necessary propellant to execute such a trajectory with enough room left over for a payload capable of global characterisation of the planet is an impressive accomplishment.”

Additionally, he said, “the team’s concept of operations that streamlines planning while optimizing the use of our payload. despite substantial thermal and power constraints, is an amazing feat.”

MESSENGER Deputy Principal Investigator Larry Nittler, of the Carnegie Institution of Washington, said that the mission has rewritten scientists’ understanding of the planet “and given us plenty of surprises.”

“Geochemical measurements have revealed a surface poor in iron, but rich in moderately volatile elements such as sulphur and sodium,” said Nittler.

“These results rule out some long-standing theories put forward to explain Mercury’s anomalously high density compared with the other planets in the inner solar system,” he explained.

“Maps of elemental abundances show that the interior is highly chemically heterogeneous, providing important clues to the early geological history of the planet.”

“MESSENGER observations have also shown that Mercury’s surface was shaped by volcanic activity, identified unique landforms shaped by loss of volatile materials, and confirmed the presence of large amounts of water ice protected from the Sun’s heat within permanently shadowed impact craters near the planet’s poles, said Nittler

Infographic with statistics on the MESSENGER mission.

Image Credit: NASA

“We have found that the complex interplay of the interplanetary magnetic field with that of Mercury results in a remarkably dynamic electromagnetic environment surrounding the planet, including unexplained bursts of electrons and highly variable distributions of different elements in the thin exosphere,” Nittler added.

“Over the next few months, MESSENGER will observe Mercury at lower altitudes and thus smaller spatial scales than ever before, and this is sure to result both in exciting scientific discoveries and new puzzles about our solar system’s enigmatic innermost planet.”

In celebration of the 10th anniversary of its launch, the MESSENGER team has released a movie acquired during an early stage of MESSENGER’s low-altitude campaign.

Messenger narrow-angle camera (NAC)

The movie provides a bird’s-eye view of what the spacecraft sees as it flies over the planet at close range and was assembled from 214 images taken by the narrow-angle camera (NAC) on June 8, 2014.

The NAC’s field of view looked toward the horizon along the direction of MESSENGER's motion as the probe crossed the terminator into night.

Scott Murchie

“This view is what a traveller on the MESSENGER spacecraft might see during low-altitude operations in the coming year,” noted MESSENGER Co-Investigator Scott Murchie of APL.

“During the final phase of its mission, MESSENGER's science instruments will use low-altitude operations like this to explore the surface and subsurface of Mercury at unprecedented resolution.”

The image frames were taken once per second while MESSENGER was at altitudes ranging from 115 to 165 kilometers, traveling at a speed of 3.7 kilometers per second relative to the surface. The movie is sped up by a factor of six for ease of viewing.

Read the full article here

NASA’s Mars Spacecraft Maneuvers to Prepare for Close Comet Flyby

This graphic depicts the orbit of comet C/2013 A1 Siding Spring as it swings around the sun in 2014. 

On Oct. 19, the comet will have a very close pass at Mars. 

Its nucleus will miss Mars by about 82,000 miles (132,000 kilometers).

Image Credit: NASA/JPL-Caltech

NASA is taking steps to protect its Mars orbiters, while preserving opportunities to gather valuable scientific data, as Comet C/2013 A1 Siding Spring heads toward a close flyby of Mars on Oct. 19.

The comet’s nucleus will miss Mars by about 82,000 miles (132,000 kilometers), shedding material hurtling at about 35 miles (56 kilometers) per second, relative to Mars and Mars-orbiting spacecraft.

At that velocity, even the smallest particle, estimated to be about one-fiftieth of an inch (half a millimeter) across, could cause significant damage to a spacecraft.

NASA currently operates two Mars orbiters, with a third on its way and expected to arrive in Martian orbit just a month before the comet flyby.

Teams operating the orbiters plan to have all spacecraft positioned on the opposite side of the Red Planet when the comet is most likely to pass by.

"Three expert teams have modeled this comet for NASA and provided forecasts for its flyby of Mars," explained Rich Zurek, chief scientist for the Mars Exploration Program at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.

"The hazard is not an impact of the comet nucleus, but the trail of debris coming from it. Using constraints provided by Earth-based observations, the modeling results indicate that the hazard is not as great as first anticipated."

"Mars will be right at the edge of the debris cloud, so it might encounter some of the particles -- or it might not."

During the day's events, the smallest distance between Siding Spring's nucleus and Mars will be less than one-tenth the distance of any known previous Earthly comet flyby.

The period of greatest risk to orbiting spacecraft will start about 90 minutes later and last about 20 minutes, when Mars will come closest to the center of the widening dust trail from the nucleus.

NASA's Mars Reconnaissance Orbiter (MRO)

NASA's Mars Reconnaissance Orbiter (MRO) made one orbit-adjustment maneuver on July 2 as part of the process of repositioning the spacecraft for the Oct. 19 event. An additional maneuver is planned for Aug. 27.

NASA's Mars Odyssey orbiter

The team operating NASA's Mars Odyssey orbiter is planning a similar maneuver on Aug. 5 to put that spacecraft on track to be in the right place at the right time, as well.

NASA's Mars Atmosphere and Volatile Evolution (MAVEN)

NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft is on its way to the Red Planet and will enter orbit on Sept. 21.

The MAVEN team is planning to conduct a precautionary maneuver on Oct. 9, prior to the start of the mission's main science phase in early November.

In the days before and after the comet's flyby, NASA will study the comet by taking advantage of how close it comes to Mars.

Researchers plan to use several instruments on the Mars orbiters to study the nucleus, the coma surrounding the nucleus, and the tail of Comet C/2013 A1 Siding Spring, as well as the possible effects on the Martian atmosphere.

This particular comet has never before entered the inner solar system, so it will provide a fresh source of clues to our solar system's earliest days.

MAVEN will study gases coming off the comet's nucleus into its coma as it is warmed by the sun.

MAVEN also will look for effects the comet flyby may have on the planet’s upper atmosphere and observe the comet as it travels through the solar wind.

Odyssey will study thermal and spectral properties of the comet's coma and tail. MRO will monitor Mars’ atmosphere for possible temperature increases and cloud formation, as well as changes in electron density at high altitudes.

The MRO team also plans to study gases in the comet’s coma. Along with other MRO observations, the team anticipates this event will yield detailed views of the comet’s nucleus and potentially reveal its rotation rate and surface features.

NASA Mars MSL Curiosity rover

Mars' atmosphere, though much thinner than Earth's, is thick enough that NASA does not anticipate any hazard to the Opportunity and Curiosity rovers on the planet's surface, even if dust particles from the comet hit the atmosphere and form into meteors.

Rover cameras may be used to observe the comet before the flyby, and to monitor the atmosphere for meteors while the comet's dust trail is closest to the planet.

Observations from Earth-based and space telescopes provided data used for modeling to make predictions about Siding Spring's Mars flyby, which were in turn used for planning protective maneuvers.

The three modeling teams were headed by researchers at the University of Maryland in College Park, the Planetary Science Institute in Tucson, Arizona, and JPL.

Voyager 3: Amateur timelapse of Jupiter 're-enacts' Voyager 1 1970 flyby

This animated gif shows Voyager 1′s approach to Jupiter during a period of over 60 Jupiter days in 1979. 

Credit: NASA

Back in the 1970′s when NASA launched the two Voyager spacecraft to Jupiter, Saturn, Uranus, and Neptune, we were all mesmerised by a movie created from Voyager 1 images of the movement of the clouds in Jupiter's atmosphere.

Voyager 1 began taking pictures of Jupiter as it approached the planet in January 1979 and completed its Jupiter encounter in early April.

During that time it took almost 19,000 pictures and many other scientific measurements to create the short movie, which you can see below, showing the intricate movement of the bright band of clouds for the first time.

Now, 35 years later a group of seven Swedish amateur astronomers achieved their goal of replicating the Voyager 1 footage, not with another flyby but with images taken with their own ground-based telescopes.

"We started this joint project back in December of 2013 to redo the NASA Voyager 1 flyby of Jupiter," amateur astronomer Göran Strand told reporters.

"During 90 days we captured 560 still images of Jupiter and turned them into 90 complete maps that covered the whole of Jupiter's surface."


Their newly released film, above details the work they did and the hurdles they overcame (including incredibly bad weather in Sweden this winter) to make their dream a reality.

They called their project "Voyager 3."

It is really an astonishing project and those of you who do image processing will appreciate the info in the video about the tools they used and how they did their processing to create this video.

The Swedish team of amateur astronomers who compiled the ‘Voyager 3′ project. 

Credit: Göran Strand

NASA Cassini Image: Flyby of Saturn's moon Phoebe

As it entered the Saturn system, NASA's Cassini spacecraft performed its first targeted flyby of one of the planet's moons.

On June 11, 2004, Cassini passed Phoebe, the largest of Saturn's outer or "irregular" moons, at an altitude of just 1,285 miles (2,068 kilometers).

This was the sole close flyby of one of the outer moons of Saturn in the entire Cassini mission.

This montage of two views is published by the Cassini team to mark the 10th anniversary of the Phoebe flyby.

The image on the left side shows Cassini's view on approach to Phoebe, while the right side shows the spacecraft's departing perspective.

Most of the left-side view was previously released as PIA06073; an area on its upper right side is newly filled in here.

Most of the view on the right side has not previously been released, although the crater at upper left is seen in PIA06074.

Phoebe's shape is approximately spherical (see PIA06070 and PIA15507 for more details), with a diameter of 136 miles (219 kilometers) on its longest axis and 127 miles (204 kilometers) on its shortest axis, which is also the rotation axis. This is approximately 16 times smaller than Earth's moon.

For several reasons, Phoebe is thought to be a captured object that does not share a joint origin with Saturn and the inner, "regular" satellites.

It orbits in a retrograde direction, opposite to the direction of Saturn's other major moons.

Its overall density was determined by Cassini scientists to be quite large for a moon of Saturn.

The prevailing view is that Phoebe might have formed in the Kuiper Belt, far beyond the orbit of Saturn. It might thus be a small cousin of the largest Kuiper Belt object, Pluto.

NASA Cassini nears 100th Titan flyby with a look back

This artist’s concept shows a possible model of Titan’s internal structure that incorporates data from NASA’s Cassini spacecraft. 

In this model, Titan is fully differentiated, which means the denser core of the moon has separated from its outer parts. 

This model proposes a core consisting entirely of water-bearing rocks and a subsurface ocean of liquid water. 

The mantle, in this image, is made of icy layers, one that is a layer of high-pressure ice closer to the core and an outer ice shell on top of the sub-surface ocean. 

Credit: A. D. Fortes/UCL/STFC

Ten years ago, we knew Titan as a fuzzy orange ball about the size of Mercury. We knew it had a nitrogen atmosphere—the only known world with a thick nitrogen atmosphere besides Earth but what might lie beneath the hazy air was still just a guess.

On March 6, NASA’s Cassini spacecraft will swoop down within 933 miles (1,500 kilometers) of Titan to conduct its 100th flyby of the Saturn moon.

Each flyby gives us a little more knowledge of Titan and its striking similarities to our world.

Even with its cold surface temperatures of minus 290 degrees Fahrenheit (94 kelvins), Titan is like early Earth in a deep freeze.

Since its 2004 arrival at Saturn, Cassini's radar instrument has identified remarkable surface features on Titan.

The features include lakes and seas made of liquid methane and ethane, which are larger than North America's Great Lakes, and an extensive layer of liquid water deep beneath the surface.

Organic molecules abound in Titan's atmosphere, formed from the breakup of methane by solar radiation.

Michael Malaska

A recent innovation was the discovery that radar could be used to determine the depth of a Titan sea.

"It's something we didn't think we could do before," said Michael Malaska, an affiliate of the Cassini radar team at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

"The radar can measure the depth by receiving two different bounces: one from the surface and one from the bottom of the sea."

"This technique was used to determine that Ligeia Mare, the second largest sea on Titan, is about 160 meters [525 feet] deep."

"When coupled with some laboratory experiments, it gives us information about the composition of the liquid in Ligeia Mare, too."

As spring turns to summer in Titan's northern hemisphere for the first time since Cassini arrived at Saturn, scientists are looking forward to entering potentially the most exciting time for Titan weather - with waves and winds picking up.

With increasing sunlight, the north polar lakes and seas can now be seen in near-infrared images, enabling scientists to learn more about their composition and giving them clues about the surrounding terrain.

Jonathan Lunine

"Methane is not only in the atmosphere, but probably in the crust," said Jonathan Lunine, a scientist on the Cassini mission at Cornell University, Ithaca, N.Y.

"It's a hint there are organics not only in Titan's air and on the surface, but even in the deep interior, where liquid water exists as well."

"Organics are the building blocks of life, and if they are in contact with liquid water, there could be a chance of finding some form of life."

Linda Spilker

Linda Spilker, Cassini project scientist at JPL, speculated on the type of life that could exist.

"The astrobiological potential for Titan is two-fold," she said. "Could a unique form of methane-based life exist in Titan's liquid lakes and seas? With a global ocean of liquid water beneath its icy crust, could life exist in Titan's subsurface ocean?"

Although the official Cassini mission name for this flyby is T-99, it is, in fact, the 100th targeted Titan flyby of the mission.

Why the discrepancy? An extra flyby was inserted early in the mission, after the Titan flybys had been named.

ESA Mars Express: Phobos Flyby - Video

On 29 December 2013, ESA's Mars Express will make the closest flyby yet of the Red Planet's moon Phobos, skimming past only 45 km above its surface.

As the spacecraft passes close to Phobos, it will be pulled slightly off course by the moon's gravity, by a few tens of centimetres. 

This small deviation will be measured using the spacecraft's radio signals, and then translated into measurements of gravity, mass and density at different locations on the moon.

ESA Mars Express heading towards daring flyby of Phobos

The High Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express took this image of Phobos using the HRSC nadir channel on 7 March 2010, HRSC Orbit 7915. 

This image has additionally been enhanced photometrically for better bringing features in the less illuminated part. Resolution: about 4.4 meters per pixel. 

Credit: ESA/DLR/FU Berlin (G. Neukum)

Late this month, ESA's Mars Express will make the closest flyby yet of the Red Planet's largest moon Phobos, skimming past at only 45 km above its surface.

The flyby on 29 December will be so close and fast that Mars Express will not be able to take any images, but instead it will yield the most accurate details yet of the moon's gravitational field and, in turn, provide new details of its internal structure.

As the spacecraft passes close to Phobos, it will be pulled slightly off course by the moon's gravity, changing the spacecraft's velocity by no more than a few centimetres per second.

These small deviations will be reflected in the spacecraft's radio signals as they are beamed back to Earth, and scientists can then translate them into measurements of the mass and density structure inside the moon.

Earlier flybys, including the previous closest approach of 67 km in March 2010, have already suggested that the moon could be between a quarter and a third empty space – essentially a rubble pile with large spaces between the rocky blocks that make up the moon's interior.

Knowing the structure of the roughly 27 x 22 x 18 km Phobos will help to solve a big mystery concerning its origin and that of its more distant sibling, Deimos, which orbits Mars at approximately three times greater distance.

The leading theories propose that the duo are either asteroids captured by Mars, or that they were born from debris thrown up from giant impacts on Mars.

The innermost moon of Mars, Phobos, is seen here in full 360 degree glory. 

The images were taken by the High Resolution Stereo Camera (HRSC) on ESA’s Mars Express at various times throughout the mission’s 10 years. 

The moon’s parallel sets of grooves are perhaps the most striking feature, along with the giant 9 km-wide Stickney impact crater that dominates one face of the 27 x 22 x 18 km moon. 

The origin of the moon’s grooves is a subject of much debate.

One idea assumes that the crater chains are associated with impact events on the moon itself. 

Another idea suggests they result from Phobos moving through streams of debris thrown up from impacts 6000 km away on the surface of Mars, with each ‘family’ of grooves corresponding to a different impact event.

Mars Express has imaged Phobos from a wide range of distances, but will make its closest flyby yet on 29 December 2013, at just 45 km above the moon. 

Although this is too close to take images, gravity experiments will give insight into the interior structure of Phobos. 

Credit: ESA / DLR / FU Berlin (G. Neukum)

"By making close flybys of Phobos with Mars Express in this way, we can help to put constraints on the origin of these mysterious moons," says Olivier Witasse, ESA's Mars Express project scientist.

In addition to probing the gravitational field of Phobos during its close approach, Mars Express will be making measurements of how the solar wind influences the moon's surface.

"At just 45 km from the surface, our spacecraft is passing almost within touching distance of Phobos," says Michel Denis, Mars Express Operations Manager.

"We've been carrying out manoeuvres every few months to put the spacecraft on track and, together with the ground stations that will be monitoring it on its close approach, we are ready to make some extremely accurate measurements at Phobos."

NASA Juno probe captures movie of Earth-Moon Flyby

When NASA's Juno spacecraft flew past Earth on Oct. 9, 2013, it received a boost in speed of more than 8,800 mph (about 7.3 kilometer per second), which set it on course for a July 4, 2016, rendezvous with Jupiter.

One of Juno's sensors, a special kind of camera optimized to track faint stars, also had a unique view of the Earth-moon system.

The result was an intriguing, low-resolution glimpse of what our world would look like to a visitor from afar.

The cameras that took the images for the movie are located near the pointed tip of one of the spacecraft's three solar-array arms.

They are part of Juno's Magnetic Field Investigation (MAG) and are normally used to determine the orientation of the magnetic sensors.

These cameras look away from the sunlit side of the solar array, so as the spacecraft approached, the system's four cameras pointed toward Earth.

Earth and the moon came into view when Juno was about 600,000 miles (966,000 kilometers) away -- about three times the Earth-moon separation.

During the flyby, timing was everything. Juno was traveling about twice as fast as a typical satellite, and the spacecraft itself was spinning at 2 rpm.

To assemble a movie that wouldn't make viewers dizzy, the star tracker had to capture a frame each time the camera was facing Earth at exactly the right instant.

The frames were sent to Earth, where they were processed into video format.

The music accompaniment is an original score by Vangelis.

Bastille Day - Paris 2013

French aerial display team Patrouille de France flew past the Eiffel tower as part of the traditional Bastille day military parade

Picture: REUTER

ESA's Rosetta flyby of asteroid Lutetia. - YouTube

A long-awaited data set is finally public (well, long-awaited by me, at least). The Rosetta team has now published their data from the July 10, 2010, flyby of asteroid (21) Lutetia.

At the time, it was the largest asteroid yet visited by a spacecraft, so it dominated the asteroids and comets montage poster I put together.

This data set is absolutely stunning, and my friends in the amateur image processing community wasted no time in creating art out of it. First, I give you a movie of Rosetta's flyby, processed by Ian Regan.

The flickering occurs because Rosetta was cycling through different-color filters as it flew past. I had to play this one a few times. Wow.

Flying People in New York City - YouTube

Three people were spotted flying around the skies of lower Manhattan last Friday, causing dropped jaws from onlookers.

But while it appeared to be flying "death eaters" of  the "Harry Potter" series, it actually turned out to be a clever piece of viral marketing for this week's upcoming film "Chronicle."

In an interview to yahoo! James Percelay, the co-founder of Thinkmodo said he and his partner Michael Krivicka were approached by 20th Century Fox, the studio behind "Chronicle," and they came out with a plan for the viral video.

Those aren't people in the air, but some very intricately designed radio-controlled airplanes. Percelay has not disclosed who exactly was piloting the planes in the video. He only said: "They are expert AMA (Academy of Model Aeronautics) members with amazing skills."

NASA ESA's Cassini Captures Saturn's Massive Storm

This false-colour mosaic from NASA's Cassini spacecraft shows the tail of Saturn's huge northern storm.

See PIA14905 to learn more about this storm and watch its development over several months.

Earlier in the Cassini mission, the spacecraft chronicled a smaller storm in the southern hemisphere called the "Dragon Storm."

See PIA06197 to learn more about that storm and to see a similar, false-colour view.

The head of the storm is beyond the horizon in this view. Saturn's atmosphere and its rings are shown here in a false colour composite made from 12 images taken in near- infrared light through filters that are sensitive to varying degrees of methane absorption.

• Red and orange colours in this view indicate clouds that are deep in the atmosphere.
• Yellow and green coloors, most noticeable near the top of the view, indicate intermediate clouds.
• White and blue indicate high clouds and haze. 

The rings appear as a thin horizontal line of bright blue because they are outside of the atmosphere and not affected by methane absorption.

The oval in the upper left of this image that appears slightly blue is the same hole in the deep clouds of the planet's atmosphere that can be seen near the tail in a larger false-color mosaic, PIA14903.

The blue colour comes from the high haze overlying the hole.

This view looks toward the northern, sunlit side of the rings from just above the ring plane. The shadow of the moon Enceladus is visible on the planet in the lower left of the image.

The images were taken with the Cassini spacecraft wide-angle camera using a combination of spectral filters sensitive to wavelengths of near-infrared light.

The images filtered at 890 nanometers are projected as blue. The images filtered at 728 nanometers are projected as green, and images filtered at 752 nanometers are projected as red.

The images were taken on Jan. 12, 2011, over about one hour at a distance of approximately 684,000 miles (1.1 million kilometers) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 52 degrees.

The images were re-projected to the same viewing geometry, so that scale in this final mosaic is 76 miles (122 kilometers) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.

The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations centre is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Image credit:NASA/JPL-Caltech/Space Science Institute

Huge Asteroid 2005 YU55's Close Encounter With Earth

In April 2010, this radar image of the near-Earth asteroid 2005 YU55 was taken by the Arecibo radio telescope in Puerto Rico. 

On Nov. 8, 2011, this large space rock zips by Earth again and will be surveyed by radar, visual and infrared equipment.

CREDIT: NASA/Cornell/Arecibo

Skywatchers hoping to glimpse a huge asteroid as it flies close by Earth Tuesday (Nov. 8) will need the right equipment and a lot of luck to spot the faint and fast-moving space rock in telescopes, scientists say.

The interloping space rock, called asteroid 2005 YU55, will pass between Earth and the orbit of the moon on Tuesday (Nov. 8), but does not pose a threat to our planet, NASA scientists have said.

The asteroid is about the size of an aircraft carrier, spanning approximately 1,300 feet (400 meters), and is the largest space rock to have a close encounter with Earth with advance notice in 35 years.

Asteroid 2005 YU55 is expected to pass closest to Earth at a range of about 201,700 miles (324,600 kilometers) on Tuesday at 6:28 p.m. EST (2328 GMT). The average distance between the moon and Earth is about 238,854 miles (384,399 km).

Skywatchers around the world are gearing up for the event, but actually spotting the asteroid as it flies by Earth could be tricky, said Scott Fisher, program director of the National Science Foundation's Division of Astronomical Sciences.

Still, the asteroid flyby will be visible from the northern hemisphere, and Fisher offered some helpful tips in an NSF webchat on Nov. 3 organized by ScienceNow

The last time a space rock as big as 2005 YU55 came as close to Earth was in 1976, although astronomers did not know about the flyby at the time. 

The next known approach of an asteroid this large will be in 2028

NASA: Flight of the Comet Hartley-2

Click on the picture to see the video clip of the Hartley-2 comet flyby. 

It is comprised of 40 frames taken from the spacecraft's Medium-Resolution Instrument during the encounter. Image credit: NASA/JPL-Caltech/UMD/Brown University
 
› See the movie here

More of the story - Flight of the Comet - NASA Jet Propulsion Laboratory

ESA: Mars express Auspicious orbit marks run-up to Phobos flyby

In a first, ESA’s Mars Express orbiter imaged the martian moons Phobos and Deimos together on 5 November 2009. Apart from their ‘wow’ factor, these unique images will help the HRSC team validate and refine existing orbit models of the two moons.

The images were acquired with the Super Resolution Channel (SRC) of the High Resolution Stereo Camera (HRSC). The camera took 130 images of the moons on 5 November at 9:14 CET in a span of 1.5 minutes at intervals of 1s, speeding up to 0.5-s intervals toward the end. The image resolution is 110 m/pixel for Phobos and 240 m/pixel for Deimos — Deimos was more than twice as far from the camera.

The Super Resolution Channel of the HRSC uses an additional lens, which has a very narrow field of view of just 0.5°, providing four times the magnification than otherwise providing four times the resolution of the HRSC colour stereo channel. Phobos, the larger of the two moons, orbits closer to the Red Planet, circling it every 7 hours and 39 minutes. It travels faster relative to Mars than the Moon relative to Earth. It was 11800 km from Mars Express when the images were taken. Deimos was 26200 kilometres away.

Credits: ESA/DLR/FU Berlin (G. Neukum)