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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

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:

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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Valentine’s Day date with a comet

Close-up view of comet Tempel 1

Pancake-layers and a possible powdery flow are among the surface features of interest highlighted in this July 4, 2005, Deep Impact image of Comet Tempel 1. The bright flash is where Deep Impact dropped a 1.8-tonne copper projectile onto the comet. Stardust-NExT could get a first look at the aftermath of the blast.

  • Stardust-NExT spacecraft to conduct fly-by of comet Tempel 1
  • Second comet fly-by for Stardust, and second spacecraft encounter for Tempel 1
  • Aim is to see changes in Tempel 1 since Deep Impact’s visit in 2005

BOTH COUPLES SEEMED meant for each other. There was the Stardust spacecraft, launched in 1999, and her cometary fiancée, Wild 2. Betrothed from afar, the two headed blissfully toward a 2004 rendezvous.

Meanwhile, the comet Tempel 1, making her own solitary way around the Sun in 2005, was heading toward a more explosive relationship with the Deep Impact spacecraft.

But alas, heavenly though the matches were—and fruitful, with each yielding valuable information about the evolution of the solar system—neither lasted. In 2006, Stardust tossed her dusty tokens of Wild 2 down to Earth for analysis and vowed to start anew.

She was a little older now; but with all her parts in good working order and adequate fuel, she was ready for a second mission. And Tempel 1, scarred by her violent encounter with Deep Impact, was looking for a kinder, gentler match.

Geometry of Stardust-NExT's Tempel 1 encounter

The Stardust spacecraft will pass within 200 kilometres of comet Tempel 1 on Feb 14 (US time)—close enough to provide a first look at the crater caused by the Deep Impact collision (bull's eye) and a large piece of previously unmapped territory (blue).

On Valentine’s Day, the two will meet. In the heat of the moment, astronomers hope, Tempel 1 will be cajoled into yielding a few more clues about her background. And Stardust, equipped with imaging and dust composition analysis instruments, will relay those clues to Earth.

Expectant matchmakers

Among the astronomers waiting patiently are Joe Veverka, professor of astronomy and principal investigator for Stardust-NExT, the NASA mission orchestrating the rendezvous.

The Valentine’s Day flyby could yield a wealth of new information about Tempel 1’s structure and composition, Veverka said, and how its features change with every passage around the Sun.

“We know that comets lose material,” he said in a recent press conference. “But the question is, ‘How does the surface change, and where does the surface change?’” Comparing the 2005 images with the new ones—taken one rotation around the Sun later—could provide the answer.

Stardust could also catch a glimpse of the crater that formed when a probe from Deep Impact crashed into Tempel 1’s surface six years ago.

“That impact threw up so much ejecta that Deep Impact never saw the crater,” Veverka said. “So it could never see how big the crater is and what [it] tells us about the mechanical properties of the surface.”

That information is vital for any future mission that involves landing a spacecraft on the surface of a comet, he said.

And finally, astronomers hope the rendezvous will provide a closer look at some of the surface features Deep Impact saw when it zoomed by in 2005. Layered terrain, for example, could contain information about how comet nuclei were formed; and smooth flows hint at some internal processes that could be working their way up to change the surface.

“Deep Impact saw only about one-third of the surface,” Veverka said. “We would like to see more.”

Stardust-NExT's first glimpse of Tempel 1

Stardust-NExT's first glimpse of Tempel 1, taken on January 18-19, 2011.

So, as February 14 approaches and other romantic souls plan candlelight dinners, Veverka and colleagues are tracking the pair, now hurtling toward each other at about 590,000 miles a day.

Stardust caught its first glimpse of Tempel 1 on January 26. It will keep its eye on the comet as it approaches, collecting data to help mission navigators refine its trajectory.

Close encounter

And on Valentine’s Day, as Earthbound lovers gaze into each other’s eyes, the two orbiting bodies will meet, about 120 miles apart. As they pass, Stardust will test the density and composition of the dust surrounding the comet and snap 72 high-resolution images.

(Note: the fly-by is due to occur at 11:37pm, US EST on February 14, which is 3:37pm February 15 Sydney time.)

Researchers expect to receive the data within a few hours of the closest encounter. “The science team is awfully excited,” Veverka said.

And thus, perhaps, the curtain will close on this cometary encore. But as with all concluded affairs, there will be months—perhaps years—of data analysis; and ultimately, plans for the next mission.

“Comets preserve some of the most faithful information about what happened when the Solar System formed,” Veverka said. “This is a step toward the ultimate answer.”

Follow Stardust-NExT on Twitter

Follow the comet encounter live on NASA TV

Stardust-NExT facts:

Stardust mission: Approved by NASA in 1995 for mission to comet Wild 2

Spacecraft manufacturer: Lockheed-Martin Aeronautics

Launch vehicle: Boeing Delta II rocket

Launch: February 7, 1999 (as Stardust)

Asteroid Anne Frank flyby: November 2, 2002

Comet Wild 2 flyby: January 2, 2004

Sample capsule return: January 15, 2006

July 3, 2007: Stardust approved for NExT mission to comet Tempel 1

Comet Tempel 1 flyby: February 14, 2011

Electrical power: Generated by solar panels

Kilometres travelled: About 5.8 billion

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

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Recycled spacecraft to revisit comet

An artist's impression of Stardust NExT approaching comet Tempel 1.

The Stardust NExT spacecraft will fly past comet Tempel 1 on February 15 (Sydney time) at a distance of only 200 kilometres.

NASA’S STARDUST NEXT SPACECRAFT is nearing a celestial date with comet Tempel 1 at approximately 3:37pm on February 15, Sydney time (11:37pm US EST on Feb 14). The mission will enable scientists for the first time to look for changes on a comet’s surface that occurred following an orbit around the Sun.

The Stardust-NExT, or New Exploration of Tempel, spacecraft will take high-resolution images during the encounter, and attempt to measure the composition, distribution, and flux of dust emitted into the coma…the cloud of material surrounding the comet’s core.

Data from the mission will provide important new information on how certain types of comets evolved and formed.

The mission will expand the investigation of the comet initiated by NASA’s Deep Impact mission. In July 2005, the Deep Impact spacecraft sent an impactor into the surface of Tempel 1 to study its composition. The Stardust spacecraft may capture an image of the crater formed by the impactor. This would be a bonus to the huge amount of data that mission scientists expect to obtain.

Here’s a short video of the result of Deep Impact’s impactor hitting Tempel 1:

“Every day we are getting closer and closer and more and more excited about answering some fundamental questions about comets,” said Joe Veverka, Stardust-NExT principal investigator at Cornell University.

“Going back for another look at Tempel 1 will provide new insights on how comets work and how they were put together four-and-a-half billion years ago.”

Close encounter of the comet kind

At approximately 336 million kilometres away from Earth, Stardust-NExT will be almost on the exact opposite side of the Solar System at the time of the encounter. (As of January 20, the spacecraft was approximately 24.6 million kilometres away from its encounter.) During the flyby, the spacecraft will take 72 images and store them in an onboard computer.

Initial raw images from the flyby will be sent to Earth for processing that will begin at approximately 7:00pm Sydney time on February 15. Images are expected to be made public 90 minutes later.

Since 2007, Stardust-NExT executed eight flight path correction manoeuvres, logged four circuits around the Sun and used one Earth gravity assist to meet up with Tempel 1.

Tempel 1 impact blast

The blast produced when an impactor released by the Deep Impact spacecraft, hit comet Tempel 1 in 2005. Scientist's hope Stardust NExT will give them a close-up look at the blast crater.

Another three manoeuvres are planned to refine the spacecraft’s path to the comet. Tempel 1’s orbit takes it as close in to the Sun as the orbit of Mars and almost as far away as the orbit of Jupiter. The spacecraft is expected to fly past the nearly 6-kilometre-wide comet at a distance of approximately 200 kilometres.

Running on empty

In 2004, Stardust became the first mission to collect particles directly from comet Wild 2, as well as interstellar dust. Samples were returned in 2006 for study via a capsule that detached from the spacecraft and parachuted to the ground southwest of Salt Lake City.

Mission controllers placed the still viable Stardust spacecraft on a trajectory that could potentially reuse the system if a target of opportunity presented itself.

In January 2007, NASA re-christened the mission Stardust-NExT and began a four-and-a-half year journey to comet Tempel 1.

“You could say our spacecraft is a seasoned veteran of cometary campaigns,” said Tim Larson, project manager for Stardust-NExT at NASA’s Jet Propulsion Laboratory.

“It’s been half-way to Jupiter, executed picture-perfect flybys of an asteroid and a comet, collected cometary material for return to Earth, then headed back out into the void again, where we asked it to go head-to-head with a second comet nucleus.”

The mission team expects this fly-by to write the final chapter of the spacecraft’s success-filled story. The spacecraft is nearly out of fuel as it approaches 12 years of space travel, logging almost 6 billion kilometres since launch in 1999.

This fly-by and planned post-encounter imaging are expected to consume the remaining fuel.

Adapted from information issued by NASA Jet Propulsion Laboratory.

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Second life: comet mission continues

Comet Hartley 2 seen by the EPOXI mission

The first view of Comet Hartley 2 (fuzz ball in the centre of the image) taken by the EPOXI mission, which is using NASA's Deep Impact spacecraft to study the comet in great detail. The rendezvous date will be November 4, 2010.

On Sunday, September 5, NASA’s Deep Impact spacecraft beamed down the first of more than 64,000 images it’s expected to take of Comet Hartley 2. The spacecraft, now on an extended mission known as EPOXI, has an appointment with the comet on November 4, 2010.

Deep Impact made headlines around the world in July 2005 when it conducted a fly-by of Comet Tempel 1 and fired a projectile into it. The projectile caused a huge explosion on impact and gouged out a huge chunk of the Temple 1’s surface and sub-surface ice, enabling Deep Impact’s instruments to give us our first view of the ice that lives below the surface of a comet.

Impact on comet Tempel 1

Flash back to 2005, when Deep Impact fired a projectile into Comet Tempel 1, causing a huge explosion that gave scientists their first look at the interior of a comet.

It was realised soon after that the Deep Impact spacecraft was still in good shape, and could be retargeted to take an up close look at a second comet, Hartley 2.

There won’t be any fireworks this time, though, as Deep Impact’s only projectile was destroyed in its deliberate 2005 collision with comet Tempel 1.

Instead, it will use all three of its instruments (two telescopes with digital colour cameras and an infrared spectrometer) to scrutinise Hartley 2 for more than two months.

The spacecraft is stilled called Deep Impact, but the mission has been renamed EPOXI…a combination of the names for the two new mission aims: 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).

Longest up-close views of a comet

“Like any tourist who can’t wait to get to a destination, we have already begun taking pictures of our comet…Hartley 2,” said Tim Larson, the project manager for EPOXI from NASA’s Jet Propulsion Laboratory.

“We have to wait for November 4 to get the close-up pictures of the cometary nucleus, but these approach images should keep the science team busy for quite some time as well.”

Deep Impact spacecraft

Artist's impression of the Deep Impact spacecraft.

The imaging campaign, along with data from all the instruments aboard Deep Impact, will afford the mission’s science team the best, extended view of a comet in history during Hartley 2’s pass through the inner Solar System.

With the exception of one, six-day break to calibrate instruments and perform a trajectory correction manoeuvre, the spacecraft will continuously monitor Hartley 2’s gas and dust output for the next 79 days.

This first image of comet Hartley 2 taken by Deep Impact was obtained by the spacecraft’s Medium Resolution Imager on September 5 when the spacecraft was 60 million kilometres (37.2 million miles) from the comet.

EPOXI is an extended mission that utilises the already “in flight” Deep Impact spacecraft to explore distinct targets of opportunity.

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

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