Philae, now idle, needs kiss of sunlight to awake

The animated image below provides strong evidence that Philae touched down for the first time almost precisely where intended. The animation comprises images recorded by Rosetta’s navigation camera as the orbiter flew over the (intended) Philae landing site on November 12th. The dark area is probably dust raised by the craft on touchdown. The boulder to the right of the circle is seen in detail in the photo below. Credit: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Contact with the Philae lander was lost at 6:36 p.m. (CST) this evening November 14th. Without sunlight to juice up its solar panels and recharge the battery, the craft will remain in “idle mode” – maybe for a long time. All its instruments and most systems on board have been shut down.

“Prior to falling silent, the lander was able to transmit all science data gathered during the First Science Sequence,” says DLR’s Stephan Ulamec, Lander manager. Contrary to earlier reports and initial speculations, Valentina Lommatsch from the German Aerospace Center explained that all three of Philae’s legs are on the ground. But the lander appears to be tipped up at an angle because one of the scenes from the panorama (below) shows mostly sky.

This image was taken by Philae’s down-looking descent ROLIS imager when it was about 131 feet  (40 meters) above the surface of the comet. The surface is covered by dust and debris ranging from millimeter to meter sizes. The large block in the top right corner is 16.4 feet (5 m) in size. In the same corner the structure of the Philae landing gear is visible. Credit: ESA/Rosetta/Philae/ROLIS/DLR

No contact will be possible unless maneuvers by controllers on the ground nudge Philae back into a sunnier spot. On its third and final landing, it unfortunately came to rest in the shadow of one of the comet’s many cliffs.

Jagged cliffs and prominent boulders are visible in this color image taken by OSIRIS, the Rosetta spacecraft’s scientific imaging system, on September 5, 2014 from a distance of 38.5 miles (62 km). Credit: ESA/Rosetta/MPS for OSIRIS team

This evening, mission controllers sent commands to rotate the lander’s main body, to which the solar panels are fixed. This may have exposed more panel area to sunlight, but we won’t know until tomorrow (Nov. 15) at 4 a.m. (CST) when the Rosetta orbiter has another opportunity to listen for Philae’s signal.

Our last panorama from Philae?  This image was taken with the CIVA camera; at center Philae has been added to show how it landed (and took the photos) while on its side. Credit: ESA

The battery was designed to power the probe for about 55 hours. Had Philae landed upright in the targeted region, its solar panels would have been out in the open and soaking up the sunlight needed for multiple recharges. There’s also the possibility that months from now, as seasons progress and solar illumination changes on the comet, the Sun will rise again over the probe.

We may hear from the lander in the coming days or not. But if not, the original plan of gathering as much science as possible in the first two days of landing was for the most part a success.

* UPDATE 7:30 a.m. Nov. 15: Some good news! Rosetta did get back in touch with Philae during the overnight pass. Data was received, but the batteries are expected to be completely drained sometime today.

Philae performs handstand on comet, sends back first panorama

The first panoramic image from the surface of a comet taken by the lander Philae. It’s a 360º view around the point of final touchdown. The three feet of Philae’s landing gear can be seen in some of the frames. Credit: ESA/Rosetta/Philae/CIVA

Beware small comets! Their lack of gravity can make landing hell. The Philae lander finally did settle down on comet 67P/Churyumov-Gerasimenko, but only after two tries. It attempted to touch down just a few hundred feet from the original planned site but with harpoons and rocket thrusters that failed to fire, there was no way for the probe to anchor itself. Instead it dropped to the surface and bounced straight back up into space a full kilometer (0.6 miles) above the comet.

Philae is superimposed on top of the panoramic image. The lander team believes it’s tipped up on its side. Credit: ESA

There it hovered for two hours until dropping down again and rebounding again about 1.5 inches (3 cm) high. In the incredibly low gravity field of the comet, Philae hovered for seven minutes! Then it finally came to rest tipped up on its side in a “handstand” position with one of its legs sticking straight up into outer space.

Stephan Ulamec, Philae Lander manager, describes where the craft landed in a press briefing today. It first touched down in the small red square at left, but then bounced off the comet and settled over two hours later somewhere inside the blue diamond. Credit: ESA

Scientists still hope to figure out a way to right the lander. As you try to make sense of the panorama, keep that in mind. In spite of its awkward stance, Philae’s still able to do a surprising amount of good science. But trouble looms. The craft landed in the shadow of a cliff, blocking sunlight to its solar panels which are used to charge its battery. Philae has one day of full power, which means tomorrow’s a critical day. If the battery runs too low, the probe will go into hibernation mode. The lander team are going to try and nudge Philae into the sunlight by operating the moving instrument called MUPUS tonight.

Philae is that little blip as photographed by Rosetta during the craft’s descent to the comet yesterday. Credit: ESA

Let’s wrap it up with a musical tribute to Rosetta and its mission. Somehow this comet landing, a major achievement despite its minor flaws, deserves a tribute in sound.


Rosetta’s Waltz by Vangelis

 

We’re on the comet, baby! Philae scores a touchdown

Rosetta team members, including  Flight Director Andrea Accomazzo (left), react to the first signal received from the Philae lander after its successful touchdown on Comet Churyumov-Gerasimenko earlier this morning. Credit: ESA

Around 9:37 a.m. (CST) Philae successfully landed on craggy comet Churyumov-Gerasimenko. The first signal, a voice from another world, arrived at 10:05. While the lander reached the surface in good health and continues to send telemetry, a small problem cropped up. The two harpoons that would anchor the craft to the comet failed to fire.

Check out this James Bond-style Swiss Army knife of a lander. Each instrument includes a short description. To read clearly, click for a large version. Credit: ESA

Right now, mission control is considering whether to re-fire them as well as figure out why they didn’t fire in the first place. In the comet’s low gravity, it’s important that Philae be sitting stably. Just think what would happen if a nearby jet erupted or ice began to vaporize around or under the craft? Weighing only a gram, Philae might easily tip over.

Here we come! The photo was taken by Philae at 8:38 a.m. (CST) when it was just 1.8 miles (3 km) above the comet. Credit: ESA/ESA/Rosetta/Philae/ROLIS/DLR

Hopefully we’ll see that first panoramic landscape photo soon. In the meantime, scientists held a press conference this afternoon to share first results as well as some of the troubles the lander faces.

Although Philae landed right on target and is gathering scientific data at this very moment, there have been problems with the radio link. Communications drop in and out for some as-yet unexplained reason. We know that neither the top rocket thruster (used to push the probe to the surface) nor the harpoons fired to anchor the craft to the comet’s surface. The data even seem to indicate that the lander may have even lifted off the ground and landed again:

Just to give you a flavor for the rugged landscape Philae was headed toward earlier today, this photo was taken by Rosetta at an altitude of 4.8 miles (7.7 km) from the comet’s surface. Credit: ESA

“Maybe today we didn’t just land once. We landed twice!” said Stephan Ulamec, Philae Lander Manager. Much is still preliminary, which is why the agency’s scientists are hard at work on the problem. Another live webcast is scheduled tomorrow at 7 a.m. (CST).

Live updates can be had on Twitter and the Rosetta website.

Philae descends to the comet, landing expected soon

The “farewell photo” taken by the Philae lander as it departed Rosetta around 2:30 a.m. (CST) today. It shows the one of the solar arrays on the spacecraft. Credit: ESA/Rosetta/Philae/CIVA

So far, so good. The European Space Agency’s Philae lander, a box of science instruments the size of a dishwasher, is now free-floating to the surface of Comet Churyumov-Gerasimenko and expected to touch down shortly. Lots more updates coming! Be sure to also check the mission’s Twitter feed.

The lander with its legs popped open photographed during its descent to the comet by Rosetta. Credit: ESA/Rosetta/MPS for Rosetta Team

Guess who’s up before midnight? By Jove, it’s Jupiter!

Brilliant Jupiter now rises in the northeastern sky before midnight. The waning gibbous Moon will join the planet Thursday November 13th. This map shows the sky facing east at midnight in mid-November. Stellarium

If the sky’s seemed devoid of evening planets of late, you’re right. Mars still hangs on in Sagittarius, but it’s so low and sets so early, few notice. Most telescopic observers have long since abandoned the planet. With an apparent diameter of three-one-thousandth’s that of the Moon, it’s just too tiny to eke out any details.

Venus is also “officially” an evening planet but still much too close the Sun to view. Enter Jupiter. This jolly bright planet joins the evening crew with a bright flourish, rising in Leo the Lion. In the days of Daylight Saving Time it rose around 1 a.m. but now catches our eyes a little before midnight low in the northeastern sky.

Jolly Jove on November 8, 2014. The two big stripes are the North (top) and South Equatorial Belts. The Great Red Spot is seen along with a cluster of smaller oval storms. Credit: Christopher Go

Earth’s revolution around the Sun causes the stars and planets in the eastern sky to rise 4 minutes earlier each evening, while those in the west set 4 minutes earlier. Over time, stars in the west get pushed out of the way as those in the east rise higher and take over the sky. It’s the astronomical equivalent of seeing each older generation swept away by the little babes whose job it is to replace us.

My point is that Jupiter, while low now, will rise an hour earlier by Thanksgiving  (16 nights x 4 mins. = 64 minutes) and nearly 3 hours earlier by Christmas. We’re soon to see a lot more of this planet. So goes the cycle of the sky.

Three of Jupiter’s four bright moons will be visible in small telescopes tonight. This view shows them around midnight (CST) tonight. North is up. Stellarium

Not only is Jupiter a pleasure to see with the naked eye – it’s so darn bright – but its dynamic weather and four bright moons offer telescope users something new to see every time we look through the eyepiece.

Because Jupiter’s 11 times larger than Earth, it presents a huge disk compared to most planets. Even with a 3-inch scope you can watch the moons shuttle back and forth and spy the largest clouds belts. The Great Red Spot, an enormous hurricane-like storm, has been shrinking over the last decade but can still be spotted in 6-inch and larger instruments.

The 2014-2015 apparition of Jupiter is special because Earth crosses through the planet’s orbital plane. Since the four brightest moons orbit almost exactly around Jupiter’s equator, we’ll get to see them eclipse and occult one another. Eclipses are especially interesting to watch – over a few minutes time you can actually watch a moon temporarily fade away. I’ll have more on these fascinating events soon.

Cloudy? Snowy? That won’t stop you from seeing THIS aurora


Aurora flyover in high-def video from the International Space Station

Wish it had been clear at dawn this morning. Some of us would have seen a very nice aurora. As predicted, Earth’s magnetic bubble got slammed by a package of high-speed solar wind overnight that fired up the northern lights. The impact continues to reverberate with more activity expected tonight.

No matter the weather or circumstance, I think you’ll enjoy this high-definition video taken from the International Space Station. The curls, rolls and flashing purple flames are, well, incredible. And there’s nothing quite like looking down on the aurora from an altitude of 250 miles (402 km). As the camera pans, you’ll also see the delicate green film of airglow, which is distinct from the northern lights – airglow surrounds the entire planet like a membrane around a cell.

Green, streaky airglow seen from the ground on July 22, 2014. Its faint light is half the reason you can always see around on even the darkest nights. The other light is provided by the stars. Credit: Bob King

Ultraviolet light from the daytime sun ionizes or knocks electrons off of oxygen and nitrogen atoms and molecules; at night the electrons recombine with their host atoms, releasing energy as light of different colors including green, red, yellow and blue.  The brightest emission, the one responsible for creating the airglow so often seen in space station nighttime images and videos, stems from excited oxygen atoms beaming emerald green light.

Forget about the clouds and take a ride with the astronauts where it’s forever clear.

Aurora alert tonight through Monday night Nov. 9-10

Aurora smolders beneath the Big Dipper tonight November 9th around 7 p.m. Credit: Bob King

Around 7 p.m. this evening, just before moonrise, a smoky green glow fired up beneath the Big Dipper low in the northern sky. The Moon rose and clouds soon followed, but we might be in for a couple nights of northern lights.

Cirrostratus clouds at moonrise this evening refracted moonlight into a pretty halo. Caught in the semi-circle is the Hyades star cluster (lower right). The Pleiades are at upper right. Credit: Bob King

A coronal mass ejection that launched from the Sun on November 7th will arrive overnight and could produce minor to moderate (G1-G2) geomagnetic storms now through midnight Monday night. The strongest activity is expected between 3-9 a.m. (CST) tomorrow morning.

A blast of high-speed electrons and protons from the Sun on November 7 looks like it may affect Earth overnight and into Monday. Credit: NASA/ESA

Tonight’s little taste will hopefully be a sign of more to come.

Philae primed for this week’s first-ever comet landing – here’s what to expect


The Tale of Rosetta and Philae and their adventures at Comet Churyumov-Gerasimenko

Comet Churyumov-Gerasimenko’s got a big week in store. On Wednesday November 12 at 10:02 a.m. (CST), it welcomes its first visitor in over 4.5 billion years – a jukebox-sized emissary from Earth named Philae (FYE-lee or FEE-lay).

Philae will land at Site J on the comet since renamed Agilkia, an island in the Nile River. Philae temple was moved there after the building of the Aswan dam flooded Philae island, the location of an inscribed obelisk that helped break the code of the Rosetta Stone and later chosen for the lander’s name.


Simulation Philae’s 7-hour descent to the Agilkia landing site.

The final decision on a go-no go for landing will be made at 1:35 a.m. Wednesday. If everything proceeds as planned, Philae’s instruments will be activated and the probe will separate from the mother ship Rosetta an hour and a half later and descend 14 miles (22.5 km) to the comet’s surface at a walking pace. While Philae tips the scales at 220-pounds (100 kg) in Earth’s gravity, it will weigh only a gram or about as much as a paper clip on the comet.

During the descent, Philae will snap some photos of the landing site. Immediately upon landing, the forward Active Descent System (ADS) thruster located on top of the lander will fire for about 15 seconds to push the probe toward the surface. That’s to make sure it doesn’t rebound on contact with the ground. Harpoons will then be fired to secure it to the surface. All this happens at 10:02 a.m. (CST).

Timeline for Philae’s descent and landing.  Each of the acronyms is the name of an instrument that the lander will use to either photograph or study the comet gas and dust emissions, magnetic field, etc. Click to see a detailed, blow-by-blow timetable. Credit: ESA

Just 5 minutes after landing, Philae will take its first photos of its new home site and transmit them back to Rosetta. Science operations and uploading of data gathered during the descent as well as the first surface measurements will also begin. The robot’s mission will last at least a week, but could continue for months. Here’s what the Rosetta website has to say:

A rare glimpse at the dark side of Comet 67P/Churyumov-Gerasimenko. Light backscattered from dust particles in the comet’s coma reveals hints of surface structures. This image was taken by the high-resolution OSIRIS camera on September 29th from a distance of approximately 12 miles (19 km). The white flecks may be comet dust or cosmic ray hits on the detector. Credit: SA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

“During the first 2.5 days the first series of scientific measurements will be completed. During this phase the lander will operate on primary battery power. In a second phase that may last up to three months, a secondary set of observations will be conducted, using backup batteries that will be recharged by the energy from the solar cells on the lander. However, no one knows precisely how long the lander will survive on the comet.”

Comet 67P/C-G on November 4th. Vaporizing ice creates the jet of material you see at right. Rosetta has detected water and carbon dioxide at the comet and also measured its current average surface temperature – chilly -57 F (-70 C). That’s a few degrees warmer than Minnesota’s record low of -60 F in February 1996. Credit: ESA/Rosetta/NAVCAM

This all assumes the craft will survive the landing. No one’s ever attempted to set down on a comet. We know there’s dust, ice, rocks and very little gravity. I’ll be biting my fingernails until we know the Philae’s sitting upright and transmitting those first photos.

NASA will cover the event live from 8 -10:30 a.m. (CST) Wednesday; ESA will also stream the landing around the same time.

Stay tuned – Wednesday will be here soon!

Spectacular meteor storm lights up Mars during recent comet flyby

On October 19, when Comet C/2013 A1 Siding Spring flew just 87,000 miles from Mars, dust from its tail set the sky aglow with a meteor storm. This illustration is my feeble attempt to show what you might have seen standing on Mars next to the Curiosity rover at the time. Credit: NASA (background) with additions and changes by Bob King

Oh, to have stood under the Martian sky on October 19th! As Comet Siding Spring passed just 87,000 miles (140,000 km) from the planet that night, dust in its tail slammed into the Martian atmosphere at 126,000 mph, burning up in storm of meteoric madness. “Thousands per hour fell,” said Nick Schneider, instrument lead for NASA’s MAVEN Imaging Ultraviolet Spectrograph. It must have looked like those classic illustrations of the 1833 and 1866 Leonid meteor storm back here on Earth.

Composite image of Comet Siding Spring and Mars taken by the Hubble Space Telescope. The images have been added together to create a single picture to illustrate the true distance or separation (1/20th the apparent size of the Full Moon) between the comet and Mars at closest approach.  Credit: NASA/ESA

I participated in a teleconference yesterday with principal investigators for the instruments on the Mars Reconnaissance Orbiter (MRO), MAVEN and Mars Express spacecraft pressed into service to study Comet Siding Spring during its historic flyby. The comet is a visitor from the faraway Oort Cloud, a spherical repository of billions of icy comets up to 1 light year from the Sun. Some 4-5 Oort Cloud comets swing through the inner solar system every year; this is the first one we’ve ever studied up close. It was discovered at Siding Spring Observatory in Australia by Robert McNaught on January 13, 2013.

NASA’s MAVEN uses its IUVS to perform a scan of the Martian atmosphere along its limb. Scans found enhanced levels of metals from vaporizing comet dust. Credit: NASA

“Dust slammed into the atmosphere and changed the chemistry of the upper atmosphere,” said Jim Green, director, Planetary Science Division, NASA Headquarters in Washington. Data from MAVEN’s UltraViolet Spectrograph (IUVS), which scans of Mars’ upper atmosphere in UV light to determine its chemical makeup, saw big spikes in the amount of magnesium and iron during the flyby. These elements are commonly found in meteorites.

Before and after scans by MAVEN. At left is a profile of the atmosphere before the comet’s arrival showing carbon dioxide and other gases; at right is during the comet’s pass. Check out that huge spike to the right – that from magnesium. Elevated levels to the left indicate iron. Credit: NASA

Siding Spring turned out to be much dustier than expected, prompting Green to later add: “It makes me very happy hid them (spacecraft) on the backside of Mars.” “It really saved them. Even one well-placed hit from a high-speed dust particle could damage an instrument, and Siding Spring peppered the Martian atmosphere with “several tons” of dust.

MAVEN used its mass spectrometer – an instrument that identifies elements by how much mass they have – to record a big enhancement of the elements magnesium, manganese, iron and others from comet dust in Mars’ atmosphere. Credit: NASA

Meanwhile, MAVEN’s Neutral Gas and Ion Mass Spectrometer (NGIMS), picked up major spikes in 8 different metals from ablating comet dust including sodium, magnesium, iron and nickel. Jim Green pointed out that the increase in sodium may have tinged the twilight sky with a yellow glow. That and a recent increase in the amount of dust in the atmosphere over the Curiosity rover site may be the reason the comet was so difficult to photograph from the ground.

Only hours after Comet Siding Spring’s closest approach, dust particles hitting air molecules on Mars formed a temporary ionized (electrified) layer in its lower ionosphere 50-60 miles high. Credit: ESA

So we have a very dusty comet, a big meteor storm, the atmosphere spiced up with metals from burning dust.

Anything else? Heck, yes. The European Space Agency’s Mars Express Orbiter used its radar to send out radio waves of very low frequency down through Mars atmosphere to record the state of the ionosphere, a rarified layer of air between 60-250 miles (100-400 km) high. At the comet’s closest approach, the ionosphere was normal, but 7 hours later, impacting dust had created a brand new, temporary ionization layer.

Close-ups pictures taken by the Mars Reconnaissance Orbiter of Comet Siding Spring around the time of closest approach to Mars. They show the combined light of the tiny nucleus and much larger coma or comet atmosphere. Comet dust / rocks range in size from 1/1000 of a millimeter to 1 centimeter (~1/2-inch). Credit: NASA

The high resolution camera on the MRO photographed brightness variations in the comet’s light, nailing down its rotation period to 8 hours. But size-wise, we’re a little less clear. Estimates for the comet’s nucleus range from 984 feet to 1.2 miles (300-m to 2 km). For comparison, Comet 67P/Churyumov-Gerasimenko, currently orbited by Europe’s Rosetta spacecraft, is 1.5 miles (2.4 km) across.

Color variations in this photo by CRISM indicate different sized dust particles being ejected by the comet. Credit: NASA

Yet another instrument named CRISM (Compact Reconnaissance Spectrometer for Mars) made some intriguing measurements of the coma showing distinct differences in color – red here, blue there – indicating the comet is blowing out dust particles of different sizes.

As scientists continue to analyze the data collected by the fleet of space probes, we’ll see more papers and results soon. For now, the rare opportunity to study a comet up close from another planet was an unqualified success. You can listen to the replay of the hour-long conference HERE.

Beauty at 225 below – a visit to Mars’ south pole

Black and white photo taken on September 10th and released this week by the Mars Odyssey spacecraft showing ice layers at Mars’ south pole. The image is 10.5 miles (17 km) across. Credit: NASA/JPL/ASU

Beautiful, isn’t it? You’re looking at multiple layers of water and carbon dioxide ice mixed with dust built up over millions of years at the south pole of Mars. Each layer or “step” varies in thickness from about 30 to 100 feet; together they make a stack up to 2.3 miles (3.7 km) high.

Mars permanent south polar cap measures about 250 miles (400 km) and consists primarily of water ice. During the southern winter, carbon dioxide in Mars’ atmosphere condenses as frost and falls as snow, whitening the planet’s southern hemisphere to latitude 50º south. Much the same happens on Earth during the winter months when snow covers the ground to across the northern and central U.S. and Canada.

The layers in these cliffs show buried ice deposits in the southern polar region of Mars at about 72°S. The image was obtained by Mars Express on January 15, 2011. Credit: ESA/DLR/FU Berlin (G. Neukum)

With a difference. On Mars, where the average temperature is -70 F but can drop as low as -225 F at the poles, snowflakes are made of dry ice, conjuring up visions of astronauts shoveling their way out of a CO2 blizzard. As the planet warms during its summer seasons, most of the frost / snow vaporizes in the sunshine and the polar caps shrink back to their norms. While the seasonal covering is primarily carbon dioxide ice, both polar caps are primarily made of good, old-fashioned water ice.

A dust storm rages near the edge of Mars north polar region on May 24, 2002. Credit: NASA

The red tint you see in the Mars Express photo shows that each layer is far from pure ice but lined with dust. Every spring, solar heating vaporizes dry ice from the pole, stoking winds that whip up dust storms. Some storms are regional; others expand to enshroud the entire planet. Later in fall, as temperatures drop, those dust particles act as condensation nuclei or particles that coax chilled carbon dioxide to condense as snowflakes. Voila! Tinted snow.

Stacked like pancakes. Close up from orbit of layered ice and dust deposits at one of the Martian poles. Credit: NASA

Variations in Mars’ climate over millions of years changes the amounts of ice and dust deposited at the poles creating the beautiful swirly layers of white and orange. Just as the study of annual tree rings tell us about past environmental conditions, planetary scientists look to the Martian poles as repositories of the planet’s climate history. Someday we’ll drill ice cores there like we do from Earth’s glaciers.

Melting ice cream? No, this is a recent view of Mars’ south polar region taken by the ESA’s Mars Express spacecraft. Dust-stained ice is everywhere. The spiral pattern might be due to prevailing winds. Click to enlarge. Credit: ESA