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Philae has landed

The European Space Agency’s (ESA) Rosetta mission has soft-landed its Philae probe on a comet, the first time in history that such an extraordinary feat has been achieved.

After a tense wait during the seven-hour descent to the surface of Comet 67P/Churyumov-Gerasimenko, the signal confirming the successful touchdown arrived on Earth at 16:03 GMT on November 12.

The confirmation was relayed via the Rosetta orbiter to Earth and picked up simultaneously by ESA’s ground station in Malargüe, Argentina and NASA’s station in Madrid, Spain. The signal was immediately confirmed at ESA’s Space Operations Centre, ESOC, in Darmstadt, and DLR’s Lander Control Centre in Cologne, both in Germany.

The first data from the lander’s instruments were transmitted to the Philae Science, Operations and Navigation Centre at France’s CNES space agency in Toulouse.

“Our ambitious Rosetta mission has secured a place in the history books: not only is it the first to rendezvous with and orbit a comet, but it is now also the first to deliver a lander to a comet’s surface,” noted Jean-Jacques Dordain, ESA’s Director General.

“With Rosetta we are opening a door to the origin of planet Earth and fostering a better understanding of our future. ESA and its Rosetta mission partners have achieved something extraordinary today.”

Philae, as seen from the Rosetta parent craft, descending to the comet.

Philae, as seen from the Rosetta parent craft, descending to the comet.

A game-changer

“After more than 10 years travelling through space, we’re now making the best ever scientific analysis of one of the oldest remnants of our Solar System,” said Alvaro Giménez, ESA’s Director of Science and Robotic Exploration.

“Decades of preparation have paved the way for today’s success, ensuring that Rosetta continues to be a game-changer in cometary science and space exploration.”

“We are extremely relieved to be safely on the surface of the comet, especially given the extra challenges that we faced with the health of the lander,” said Stephan Ulamec, Philae Lander Manager at the DLR German Aerospace Centre.

“In the next hours we’ll learn exactly where and how we’ve landed, and we’ll start getting as much science as we can from the surface of this fascinating world.”

Rosetta was launched on 2 March 2004 and travelled 6.4 billion kilometres through the Solar System before arriving at the comet on 6 August 2014.

“Rosetta’s journey has been a continuous operational challenge, requiring an innovative approach, precision and long experience,” said Thomas Reiter, ESA Director of Human Spaceflight and Operations.

“This success is testimony to the outstanding teamwork and the unique know-how in operating spacecraft acquired at the European Space Agency over the decades.”

510 million kilometres from Earth

The landing site, named Agilkia and located on the head of the bizarre double-lobed object, was chosen just six weeks after arrival based on images and data collected at distances of 30–100 km from the comet.

Those first images soon revealed the comet as a world littered with boulders, towering cliffs and daunting precipices and pits, with jets of gas and dust streaming from the surface.

Following a period spent at 10 km to allow further close-up study of the chosen landing site, Rosetta moved onto a more distant trajectory to prepare for Philae’s deployment.

Philae's first view from the surface of Comet 67P/Churyumov-Gerasimenko. One of the lander’s three feet can be seen in the foreground. The image is a two-image mosaic.

Philae’s first view from the surface of Comet 67P/Churyumov-Gerasimenko. One of the lander’s three feet can be seen in the foreground. The image is a two-image mosaic.

Five critical go/no-go decisions were made last night and early this morning, confirming different stages of readiness ahead of separation, along with a final pre-separation manoeuvre by the orbiter.

Deployment was confirmed at 09:03 GMT (10:03 CET) at a distance of 22.5km from the centre of the comet. During the seven-hour descent, which was made without propulsion or guidance, Philae took images and recorded information about the comet’s environment.

“One of the greatest uncertainties associated with the delivery of the lander was the position of Rosetta at the time of deployment, which was influenced by the activity of the comet at that specific moment, and which in turn could also have affected the lander’s descent trajectory,” said Sylvain Lodiot, ESA Rosetta Spacecraft Operations Manager.

“Furthermore, we’re performing these operations in an environment that we’ve only just started learning about, 510 million kilometres from Earth.”

Not all went according to plan

Touchdown was planned to take place at a speed of around 1 m/s, with the three-legged landing gear absorbing the impact to prevent rebound, and an ice screw in each foot driving into the surface.

But during the final health checks of the lander before separation, a problem was detected with the small thruster on top that was designed to counteract the recoil of the harpoons to push the lander down onto the surface.

The conditions of landing – including whether or not the thruster performed – along with the exact location of Philae on the comet are being analysed.

An extended science phase using the rechargeable secondary battery may be possible, assuming Sun illumination conditions allow and dust settling on the solar panels does not prevent it.

This extended phase could last until March 2015, after which conditions inside the lander are expected to be too hot for it to continue operating.

Philae's first multi-image panorama from the surface of the comet.

Philae’s first multi-image panorama from the surface of the comet.

Answering the big questions

Science highlights from the primary phase will include a full panoramic view of the landing site, including a section in 3D, high-resolution images of the surface immediately underneath the lander, on-the-spot analysis of the composition of the comet’s surface materials, and a drill that will take samples from a depth of 23 cm and feed them to an onboard laboratory for analysis.

The lander will also measure the electrical and mechanical characteristics of the surface. In addition, low-frequency radio signals will be beamed between Philae and the orbiter through the nucleus to probe the internal structure.

The detailed surface measurements that Philae makes at its landing site will complement and calibrate the extensive remote observations made by the orbiter covering the whole comet.

“Rosetta is trying to answer the very big questions about the history of our Solar System. What were the conditions like at its infancy and how did it evolve? What role did comets play in this evolution? How do comets work?” said Matt Taylor, ESA Rosetta project scientist.

“Today’s successful landing is undoubtedly the cherry on the icing of a 4 km-wide cake, but we’re also looking further ahead and onto the next stage of this ground-breaking mission, as we continue to follow the comet around the Sun for 13 months, watching as its activity changes and its surface evolves.”

A long and hard journey

While Philae begins its close-up study of the comet, Rosetta must manoeuvre from its post-separation path back into an orbit around the comet, eventually returning to a 20 km orbit on 6 December.

Next year, as the comet grows more active, Rosetta will need to step further back and fly unbound ‘orbits’, but dipping in briefly with daring flybys, some of which will bring it within just 8 km of the comet centre.

The comet will reach its closest distance to the Sun on 13 August 2015 at about 185 million km, roughly between the orbits of Earth and Mars. Rosetta will follow it throughout the remainder of 2015, as they head away from the Sun and activity begins to subside.

“It’s been an extremely long and hard journey to reach today’s once-in-a-lifetime event, but it was absolutely worthwhile. We look forward to the continued success of the great scientific endeavour that is the Rosetta mission as it promises to revolutionise our understanding of comets,” said Fred Jansen, ESA Rosetta mission manager.

You can keep up to date with the latest Rosetta news at ESA’s Rosetta blog.

Adapted from information issued by ESA. Images courtesy ESA / Rosetta / Philae / CIVA.

Comet wows earthlings and astronauts

Comet Lovejoy over Santiago de Chile

This beautiful dawn photo of Comet Lovejoy over Santiago de Chile was taken by European Southern Observatory photo ambassador Yuri Beletsky on December 22 at 5:00am.

MANY THOUGHT IT WOULDN’T SURVIVE, but a comet discovered by an Australian amateur astronomer has zipped past the Sun at an extremely close distance and lived to tell the tale.

Comet Lovejoy was discovered by Terry Lovejoy (Queensland) on November 27. It quickly became clear that it was going to pass very close to the Sun, making it a Kreutz-class sungrazing comet.

In fact, at the time of closest approach, the distance between the comet and the Sun’s surface was only 140,000 kilometres—that’s only one-third of the distance between the Earth and the Moon!

So you can see why it wasn’t expected to survive. Comets are made of a mixture of ice, dust and rock, and are fairly fragile bodies. The intense heating experienced during a close encounter with the Sun is enough to make many sungrazing comets break apart and vaporise.

But not Comet Lovejoy! It went behind the Sun (as seen from Earth) and, as luck would have it, swung back into view even more spectacular than before.

Here are a couple of videos showing the close encounter. The first is from the STEREO spacecraft, and the second is the Solar Dynamics Observatory spacecraft…both of which continually monitor the Sun.

The view from space was just as spectacular. Aboard the International Space Station, mission commander Dan Burbank captured the scene from almost 400 kilometres up, calling it “the most amazing thing I have ever seen in space”. Here’s the video:

And here’s more of what he had to say about the view:

And here’s a short time-lapse of images taken at the European Southern Observatory’s Paranal site in Chile, showing what it looked like from a dark site on the ground.

Adapted from information issued by NASA / Dan Burbank / SDO / G. Blanchard (eso.org/~gblancha) / ESO / Y. Beletski.

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Rain of comets in alien star system

Artist's conception of the Eta Corvi star system

This artist's conception illustrates a storm of comets in the Eta Corvi star system. Evidence for this barrage comes from NASA's Spitzer Space Telescope, whose infrared detectors picked up indications that one or more comets was recently torn to shreds after colliding with a rocky body.

NASA’S SPITZER SPACE TELESCOPE has detected signs that icy bodies are raining down in an alien planetary system. The downpour resembles our own Solar System several billion years ago during a period known as the ‘Late Heavy Bombardment,’ when water and other life-forming ingredients may have been brought to Earth.

During this epoch, comets and other frosty objects that were flung inwards from the outer Solar System pummelled the inner planets. The barrage scarred our Moon and produced large amounts of dust.

Now Spitzer has spotted a band of dust around a nearby star called Eta Corvi that strongly matches the contents of an obliterated giant comet. This dust is located close to Eta Corvi, where Earth-sized worlds could exist, suggesting a collision took place between a planet and one or more comets.

The Eta Corvi system is approximately one billion years old, which researchers think is about the right age for such a hailstorm.

Similar to our Solar System

Astronomers used Spitzer’s infrared detectors to analyse the light coming from the dust around Eta Corvi. Certain chemical fingerprints were observed, including water ice, organics and rock, which indicate a giant comet source.

The light signature emitted by the dust around Eta Corvi also resembles the Almahata Sitta meteorite, which fell to Earth in fragments across Sudan in 2008. The similarities between the meteorite and the object obliterated in Eta Corvi imply a common birthplace in their respective planetary systems.

A second, more massive ring of colder dust located at the far edge of the Eta Corvi system seems like the proper environment for a reservoir of cometary bodies. This bright ring, discovered in 2005, is about 150 times the distance from Eta Corvi as the Earth is from the Sun.

Our Solar System has a similar region, known as the Kuiper Belt, where icy and rocky leftovers from planet formation linger. The new Spitzer data suggest that the Almahata Sitta meteorite may have originated in our own Kuiper Belt.

Adapted from information issued by NASA / JPL-Caltech / R. Hurt (SSC).

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Comet’s death dive into the Sun

A TYPE OF COMET KNOWN AS a sun-grazer has met a fiery end, plunging into the Sun and evaporating.

The event was captured by the Solar Dynamics Observatory (SOHO) spacecraft, which continually monitors the Sun. In the video above, the comet can be seen approaching from the bottom right.

According to SOHO Project Scientist Bernhard Fleck, “this is one of the brightest sun-grazers SOHO has recorded…”

Comets diving in towards the Sun are a fairly common event.

Scientists were delighted with this particular event—the SOHO spotted the comet as it disintegrated over about a ten-hour period, something never observed before.

The angle of the comet’s orbit brought it across the front half of the Sun where it seemed to brighten when it stuck hotter masses of particles above the Sun’s surface.

Adapted from information issued by NASA / ESA.

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Comet doomsday nonsense

Artist's impression of a comet

Artist's impression of a comet. Comet C/2010 X1 (Elenin) will make a distant fly-by of Earth in October 2011.

I WAS ASKED THE OTHER NIGHT (by a caller while I was a guest on Tony Delroy’s Nightlife show on ABC radio), whether there is any truth to the rumour that Earth is going to be buzzed—perhaps even hit—by a comet later this year.

I must admit I hadn’t been keeping my eye on cometary matters lately, so I wasn’t able to give the caller a detailed reply. What I did say was that if a very close approach by a comet were on the cards, let alone a collision, I was sure I would have heard about it.

But I promised to investigate the matter and post something about it on SpaceInfo.com.au

Hunting around, it seems the caller had heard about Comet C/2010 X1 (Elenin), which was discovered on 10 December 2010.

Elenin is a long-period comet (ie. with an orbital period longer than 200 years) that is estimated to have a solid icy core, or nucleus, about 3 to 4 kilometres wide. Quite average for a comet.

As far as visibility for Earth-bound observers is concerned, there are two points that matter in a comet’s orbit—the point of its closest approach to the Sun, called perihelion, and its closest approach to Earth, called perigee.

A comet shines by light reflected from the gas and dust cloud that builds up around its icy nucleus—gas and dust that has been liberated from its frozen surface by the Sun’s heat. The point around perihelion is important, as this is where the most gas and dust can be expected to be liberated. (Technically speaking, the ice does not evaporate, which involves a liquid phase—it sublimates, which is when ice turns directly into gas.) The more gas and dust, the more reflected sunlight, and the brighter the overall comet will appear to be.

The time around perigee is important too, as being closest to Earth the comet will appear larger (and therefore brighter).

In the case of Elenin, perihelion will occur on 10 September 2011, and perigee will be reached on 16 October 2011 at a distance of about 34 million kilometres.

Is that close? No, it’s a long way away. It’s about 100 times further than the Moon, which means Elenin poses no threat to Earth at all.

So if you come across any Elenin doomsday stories on the Internet, please disregard them—they are nonsense.

South Australian amateur astronomer Ian Musgrave has a great set of Elenin questions and answers on his Astroblog site.

Story by Jonathan Nally.

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The day we met Halley

HISTORY WAS MADE 25 years ago when a small spacecraft swept to within 600 km of Halley’s comet. The European Space Agency’s (ESA) Giotto probe was nearly destroyed by the encounter, but what it saw changed our picture of comets forever.

As debuts go, it doesn’t get any better than Giotto. The spacecraft was ESA’s first deep-space mission. Built to a design that drew on the Geos Earth-orbiting research satellites, it was fitted with shielding to protect it from the ‘sand-blasting’ it was going to receive as it sped through the comet’s tail.

It was originally conceived as a joint mission with NASA, the Tempel-2 Rendezvous-Halley Intercept mission. When the USA pulled out after budget cuts, ESA took the bold decision to forge on, finding Japan and Russia willing to contribute their own missions. Together, they sent a flotilla, with the Russian missions serving as pathfinders to guide Giotto to its dangerous encounter.

Comet Halley's nucleus

Giotto's encounter with Comet Halley provided the first ever opportunity to take images of a comet nucleus, which turned out to be blacker than coal.

Scientists, controllers and engineers gathered at ESA’s control centre in Darmstadt, Germany, on the night of 13-14 March 1986 to witness the flyby.

“It was a once-in-a-lifetime event and it had a big impact on the general public,” says Giotto’s former Deputy Project Scientist, Gerhard Schwehm.

Heart of the comet

The scientific harvest from Giotto changed people’s perception of comets. By measuring its composition, Giotto confirmed Halley as a primitive remnant of the Solar System, billions of years old. It detected complex molecules locked in Halley’s ices that could have provided the chemical building blocks of life on Earth.

Yet the biggest triumph was the image of Halley itself. “It may sound simple to say that but the picture was the best thing, the moment you saw it…it was tremendous,” remembers Gerhard.

Countless people have seen the ghostly shimmer of Halley’s comet from Earth. Records of it stretch back to China in 240 BCE. It famously appears on the Bayeux Tapestry, and the Italian artist Giotto di Bondone used it to symbolize the star of Bethlehem in his masterpiece, The Adoration of the Magi.

Part of the Bayeux Tapestry

Comet Halley, in its 1066 appearance, is shown in the Bayeux Tapestry.

But none saw what his spacecraft namesake saw: the very heart of the comet, the nucleus.

Just 10 x 15 km, it surprised everyone by being darker than coal, reflecting just 4% of the light falling on its surface.

Instead of the whole surface boiling away, ‘jets’ were localized in specific areas.

Life after Halley

Giotto nearly did not survive. As expected, the probe was pummelled. Dust from the comet ripped into it at speeds of 68 km/s, eroding away the shielding and the sensors, destroying the camera.

But Giotto itself lived on and was sent to meet a second comet, Grigg-Skjellerup, in 1992.

Since Giotto’s encounter, Halley has continued its journey, covering about a third of its 76-year orbit. Although it will not return until 2061, there are other cometary targets.

“Giotto ignited the planetary science community in Europe—we had demonstrated that we could successfully lead demanding missions—and people started thinking about what else we could do,” says Gerhard.

Artist's impression of the Rosetta spacecraft

ESA's Rosetta spacecraft is on its way to a rendezvous with Comet 67P/Churyumov-Gerasimenko in 2014.

ESA’s Rosetta mission is next. The spacecraft is en route to comet Churyumov-Gerasimenko, for arrival in 2014. It will study the comet and release a lander to analyse the surface material.

Recently, Rosetta flew by asteroid Lutetia and is now preparing to hibernate for the rest of its cruise. Once at Churyumov-Gerasimenko, Rosetta will follow the comet for months.

Where Giotto gave us the night of the comet, Rosetta promises the year of the comet.

Adapted from information issued by ESA. Image credits: Halley Multicolour Camera Team / Giotto Project / ESA / AOES Medialab.

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Comet rendezvous “100% successful”

Four different Stardust views of Tempel 1

Four different views of comet Tempel 1 as seen by NASA's Stardust spacecraft as it flew by on Feb. 14, 2011. The images progress in time beginning at upper left, moving to upper right, then proceeding from lower left to lower right. The upper right and lower left images are the best ones, taken at 3 seconds before, and 3 seconds after, the closest approach.

NASA’S STARDUST SPACECRAFT returned new images of a comet showing a scar resulting from the 2005 Deep Impact mission. The images also showed that the comet has a fragile and weak core or nucleus.

The spacecraft made its closest approach to comet Tempel 1 on Tuesday, February 15 at 3:40pm Sydney time (Monday, Feb. 14 at 8:40pm US PST or 11:40pm US EST) at a distance of approximately 178 kilometres (111 miles).

Stardust took 72 high-resolution images of the comet. It also accumulated 468 kilobytes of data about the dust in its coma, the cloud that is a comet’s atmosphere.

The craft is on its second mission of exploration called Stardust-NExT, having completed its prime mission collecting cometary particles and returning them to Earth in 2006.

The Stardust-NExT mission met its goals, which included observing surface features that changed in areas previously seen during the 2005 Deep Impact mission; imaging new terrain; and viewing the crater generated when the 2005 mission propelled an impactor at the comet.

“This mission is 100 percent successful,” said Joe Veverka, Stardust-NExT principal investigator of Cornell University, Ithaca, N.Y. “We saw a lot of new things that we didn’t expect, and we’ll be working hard to figure out what Tempel 1 is trying to tell us.”

Location of the impact by the impactor from the Deep Impact

Close up of the location hit by the impactor from the Deep Impact spacecraft back in 2005.

Before-and-after comparison of part of Tempel 1

This pair of images shows the before-and-after comparison of the part of comet Tempel 1 that was hit by the impactor from NASA's Deep Impact spacecraft back in 2005.

Like flying through WWII flak

Several of the images provide tantalising clues to the result of the Deep Impact mission’s collision with Tempel 1.

“We see a crater with a small mound in the centre, and it appears that some of the ejecta went up and came right back down,” said Pete Schultz of Brown University. “This tells us this cometary nucleus is fragile and weak based on how subdued the crater is we see today.”

Engineering telemetry downlinked after closest approach indicates the spacecraft flew through waves of disintegrating cometary particles, including a dozen impacts that penetrated more than one layer of its protective shielding.

“The data indicate Stardust went through something similar to a B-17 bomber flying through flak in World War II,” said Don Brownlee, Stardust-NExT co-investigator from the University of Washington in Seattle. “Instead of having a little stream of uniform particles coming out, they apparently came out in chunks and crumbled.”

Changes in the surface of Tempel 1

This image layout depicts changes in the surface of comet Tempel 1, observed first by NASA's Deep Impact Mission in 2005 (top) and again by NASA's Stardust-NExT mission on February 14, 2011 (bottom).

Mission almost over

While the Valentine’s Day night encounter of Tempel 1 is complete, the spacecraft will continue to look at its latest cometary obsession from afar.

“This spacecraft has logged over 3.5 billion miles [5.6 billion kilometres] since launch, and while its last close encounter is complete, its mission of discovery is not,” said Tim Larson, Stardust-NExT project manager at JPL. “We’ll continue imaging the comet as long as the science team can gain useful information, and then Stardust will get its well-deserved rest.”

Stardust-NExT is a low-cost mission that is expanding the investigation of comet Tempel 1 initiated by the Deep Impact spacecraft. The mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver built the spacecraft and manages day-to-day mission operations.

Adapted from information issued by NASA JPL. Images courtesy NASA / JPL-Caltech / University of Maryland / Cornell.

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Comet fly-by success!

Comet Tempel 1

NASA's Stardust-NExT mission took this image of comet Tempel 1 at 8:36pm US PST (11:36pm US EST) on Feb 14, 2011, from a distance of approximately 2.20 thousand kilometres.

MISSION CONTROLLERS at NASA’s Jet Propulsion Laboratory watched as data downlinked from the Stardust spacecraft indicated it completed its closest approach with comet Tempel 1.

Preliminary data transmitted from the spacecraft indicated the time of closest approach was about 3:39pm Tuesday, Sydney time (Monday, 8:39pm US PST or 11:39pm US EST), at a distance of 181 kilometres from Tempel 1.

An hour after closest approach, the spacecraft turned to point its large, high-gain antenna at Earth to start sending back the 72 images taken during the fly-by.

Soon after the first images began arriving, it became apparent that an unknown glitch had changed the order in which they were being sent.

Mission controllers had commanded the spacecraft to send the middle five images first. These are the ones that were taken at the time of closest approach, when the comet would have filled the frame and lots of detail would be seen.

Instead, Stardust-NExT began sending the images in the order they were taken, starting with distant shots showing a small comet nucleus surrounded by the black of space.

The first six of those images were released shortly after they arrived from the spacecraft. They all look pretty much the same, so we’re showing only two of them with this story.

Comet Tempel 1

NASA's Stardust-NExT mission took this image of comet Tempel 1 at 8:35pm US PST (11:35pm US EST) on Feb 14, 2011, from a distance of approximately 2.28 thousand kilometres.

A press conference originally scheduled for 5:00am Sydney time Wednesday (Tuesday, 10:00am US PST or 1:00pm US EST) has been rescheduled for 8:00am Sydney time (Tuesday, 4:00m US EST). It is expected that the good images will be released during that conference.

You can watch the press conference live on NASA TV.

Adapted from information issued by NASA / JPL-Caltech / Cornell.

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Comet encounter today

Artist's concept of NASA's Stardust-NExT mission

Artist's concept of NASA's Stardust-NExT mission approaching comet Tempel 1.

AS OF TODAY, February 15 at 4:21am Sydney time (Feb 14, at 9:21am US PST or 12:21pm US EST), NASA’s Stardust-NExT mission spacecraft was within 402,336 kilometres of its quarry, comet Tempel 1, which it will fly by today.

The spacecraft is cutting the distance with the comet at a rate of about 10.9 kilometres per second (38,000 kph).

The flyby of Tempel 1 will give scientists an opportunity to look for changes on the comet’s surface since it was visited by NASA’s Deep Impact spacecraft in July 2005. Since then, Tempel 1 has completed one orbit of the Sun, and scientists are looking forward to discovering any differences in the comet.

The closest approach is expected tonight at approximately 3:40pm Sydney time (8:40pm US PST or 11:40pm US EST).

A brief encounter

During the encounter phase, the spacecraft will carry out many important milestones in short order and automatically, as the spacecraft is too far away to receive timely updates from Earth.

These milestones include turning the spacecraft to point its protective shields between it and the anticipated direction from which cometary particles would approach.

Another milestone will occur at about four minutes to closest approach, when the spacecraft will begin science imaging of the comet’s nucleus.

Composite image of comet Tempel 1

This composite image was taken by NASA's Stardust spacecraft 42 hours before its encounter with comet Tempel 1. It is the last image by the spacecraft's navigation camera before its encounter with the comet. The image is a composite of four, five-second exposures.

The nominal imaging sequence will run for about eight minutes. The spacecraft’s onboard memory is limited to 72 high-resolution images, so the imaging will be most closely spaced around the time of closest approach for best-resolution coverage of Tempel 1’s nucleus.

At the time of closest encounter, the spacecraft is expected to be approximately 200 kilometres from the comet’s nucleus.

The mission team expects to begin receiving images on the ground starting at around 7pm Sydney time (midnight US PST or 3:00am on Feb. 15 US EST). Transmission of each image will take about 15 minutes.

It will take about 10 hours to complete the transmission of all images and science data aboard the spacecraft.

Watch the live coverage

Live coverage on NASA TV and via the Internet begins at 3:30pm Sydney time (Feb. 14 at 8:30pm US PST or 11:30pm US EST) from mission control at NASA’s Jet Propulsion Laboratory. Coverage also will include segments from the Lockheed Martin Space System’s mission support area in Denver.

For NASA TV streaming video, scheduling and downlink information, visit http://www.nasa.gov/ntv

The live coverage and news conference will also be carried on one of JPL’s Ustream channels. During events, viewers can take part in a real-time chat and submit questions to the Stardust-NExT team at: http://www.ustream.tv/user/NASAJPL2

During its 12 years in space, Stardust became the first spacecraft to collect samples of a comet (Wild 2 in 2004), which were delivered to Earth in 2006 for study.

The Stardust-NExT mission is managed by JPL for NASA’s Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver built the spacecraft and manages day-to-day mission operations.

Adapted from information issued by NASA / JPL. Images courtesy NASA / JPL-Caltech / Cornell / LMSS.

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Video of comet fly-by

  • NASA’s EPOXI mission flew past Comet Hartley 2
  • Only 5th time a comet’s nucleus has been seen up close

A new video clip has been compiled from images taken by NASA’s EPOXI mission spacecraft during its flyby of comet Hartley 2 on November 4-5, 2010.

During the encounter, the spacecraft and comet whisked past each other at a speed of over 44,000 kilometres per hour (27,560 miles per hour). The spacecraft came within about 700 kilometres (435 miles) of the comet’s nucleus at the time of closest approach.

“While future generations should have the opportunity to truly explore comets, this flyby gives us an excellent preview of what they will get to enjoy,” said EPOXI principal investigator Michael A’Hearn of the University of Maryland, College Park. “Hartley 2 exceeded all our expectations in not only scientific value but in its stark majestic beauty.”

The video clip of the flyby is comprised of 40 frames taken from the spacecraft’s Medium-Resolution Instrument during the encounter. The first image was taken at about 37 minutes before the time of closest approach at a distance of about 27,350 kilometres (17,000 miles).

The last image was taken 30 minutes after closest approach at a distance of 22,200 kilometres (13,800 miles). The spacecraft was able to image nearly 50 percent of the comet’s illuminated surface in detail.

The EPOXI mission’s flyby of comet Hartley 2 was only the fifth time in history that a comet nucleus has been imaged, and the first time in history that two comets have been imaged with the same instruments and same spatial resolution.

EPOXI is an extended mission that utilises the already “in flight” Deep Impact spacecraft to explore distinct celestial targets of opportunity. The name EPOXI itself is a combination of the names for the two extended mission components: the extrasolar planet observations, called Extrasolar Planet Observations and Characterisation (EPOCh), and the flyby of comet Hartley 2, called the Deep Impact Extended Investigation (DIXI). The spacecraft will continue to be referred to as “Deep Impact.”

Adapted from information issued by NASA / JPL / University of Maryland.

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