Video: Like two spaceships passing in the night

  1. Transcript of: Like two spaceships passing in the night

    BRIAN WILLIAMS, anchor: We have some news tonight from deep space. Stunning images of a comet called Hartley 2 that's hurtling along on the very fringes of our solar system. A NASA spacecraft got close, at least in space terms, to the comet and started sending back images within an hour of this flyby. The spacecraft was launched back in 2005 . It takes a while. It's traveled 1.7 billion miles in its way

updated 11/4/2010 10:19:11 PM ET 2010-11-05T02:19:11

A spacecraft's close encounter with a comet went off without a hitch on Thursday, and the data it's beaming down is already surprising scientists.

NASA's Deep Impact probe zipped to within 435 miles (700 kilometers) of Comet Hartley 2 at 10:01 a.m. ET, and it sent the first five close-up photos of the peanut-shaped comet to Earth about an hour later.

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Scientists are already poring over these images, as well as thousands of others that Deep Impact has taken of the comet since early September. The spacecraft's observations paint a picture of a strange comet that's tremendously active for its small size, with jets fueled by carbon dioxide spouting voluminously from a rough, textured surface. [ First close-up photos of Comet Hartley 2]

Researchers hope the flyby — one of just five missions that have photographed a comet's nucleus up-close — will help them gain a better understanding of comet structure and behavior. Since comets are leftovers from the solar system's early days, such knowledge could reveal a great deal about how our cosmic neighborhood came to be.

But researchers stressed that there's still a great deal of work to be done, as Deep Impact has already delivered a mountain of data and will keep pouring it on through late November.

"The engineers did a fantastic job of getting us data," said Mike A'Hearn of the University of Maryland, principal investigator of Deep Impact's comet flyby mission, which NASA calls EPOXI. "The scientific work is just beginning now."

Early scientific returns
Researchers have only just begun studying the first few images from the close flyby, and they've got a lot of work ahead of them. By the time Deep Impact takes its eyes off Hartley 2 around Thanksgiving, the probe will have delivered about 120,000 comet images to researchers' computers, NASA officials said.

An intriguing picture of Hartley 2 is already emerging.

Hartley 2 is smaller than the other four comets that were previously imaged up-close — measuring just 1.25 miles (2 kilometers) across — but it is incredibly active, with many jets spouting gas and dust.

The comet was discovered in 1986 by Australian astronomer Malcolm Hartley and orbits the sun once every six and a half years.

Comets, cyanide and CO2 jets
Deep Impact observations have revealed that Hartley 2's jets are fueled primarily by carbon dioxide — a surprise, since most comet outgassing is thought to be driven by water, A'Hearn said.

While jets had been observed on other comets before, the close flyby pinpointed Hartley 2's jets to an unprecedented degree, revealing that many of them are coming from areas with rough terrain.

"This the first time that we can track these jets to individual topographical features on the nucleus," A'Hearn said.

Image: Malcolm Hartley
Reed Saxon  /  AP
Malcolm Hartley, of Australia, the astronomer who discovered Comet Hartley 2, looks back from a computer image of the comet after the first images from the NASA Deep Impact spacecraft came in to the Jet Propulsion Laboratory in Pasadena, Calif., on Thursday.

The close encounter further revealed that the jets erupt from many different parts of Hartley 2, not just the areas heated most by sunlight — another surprise, and one that has researchers scratching their heads.

"There are jets in the nighttime, jets along the edge and jets in the sun," said Jessica Sunshine, an EPOXI scientist from the University of Maryland. "We have a lot of work to do to figure out what's going on."

In September, Deep Impact also observed huge jets of cyanide gas from Hartley 2. The comet coughed up a few million tons of the stuff over the course of two weeks. And it puffed out the poisonous gas without dragging out any dust, A'Hearn said — yet another surprise, since such exhalations usually bring with them grainy materials from the interior.

"That's a phenomenon we haven't seen before," A'Hearn said. "We don't understand that yet."

Scientists aren't drawing many conclusions yet about what Hartley 2 is made of; they need to wait for more data to come home from Deep Impact's infrared spectrometer instrument, according to Sunshine. But researchers are ready for the unexpected.

"I think some surprises are yet to come on the compositional side," Sunshine said.

Going off without a hitch
Cheers erupted in the mission control room at NASA's Jet Propulsion Laboratory when the five close-encounter images of Hartley 2 flashed up on the big screen Thursday morning. Scientists clapped, whooped and wandered about, shaking hands to celebrate a job well done.

"We couldn't have asked for a better performance from our spacecraft and our navigation team," EPOXI project manager Tim Larson of JPL told reporters. "It was a huge moment for our team."

Deep Impact was on the ball, Larson said, making its rendezvous with Hartley 2 within 2 seconds of the planned time. When the probe began beaming images back to Earth just about on schedule, the team knew the mission was a success.

"That was hugely gratifying," Larson said.

Cracking the comet code
Scientists will continue digging into the data as it pours in. The ultimate goal of Deep Impact's mission, A'Hearn said, is to try to learn how comets have been shaped over the eons since the solar system's birth.

If they can learn which aspects of the structure and behavior of comets date back to 4.5 billion years ago, researchers can draw more conclusions about the solar system's birth and about planet formation, according to A'Hearn.

While scientists ponder such big questions, Comet Hartley 2 will continue to zoom around the sun — for a while. The sun appears to be cooking 3 to 5 feet (1 to 1.5 meters) of material off the comet's surface on each orbit, A'Hearn said. Hartley 2's smallest side measures just 1,650 feet (500 meters), so the comet's days are numbered.

"It won't be around very long," A'Hearn said.

Deep Impact's future foretold
Deep Impact, for its part, is in limbo after its comet observations end around Thanksgiving.

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The $252 million spacecraft went the extra mile — 2.9 billion extra miles, actually — to chase down Hartley 2.

Deep Impact was originally designed to serve as mothership and observer on a 2005 mission to crash an 820-pound (371-kilogram) probe into Comet Tempel 1.

After Deep Impact completed this mission successfully, NASA scientists repurposed it to hunt down Hartley 2. The extended mission cost about $45 million.

Now, Deep Impact is almost out of fuel. It doesn't have enough left to make another comet close encounter, but researchers could possibly use it as more of a stationary observing platform, according to Larson. Whether that will happen, or whether NASA will just decommission the probe — that's all up in the air.

"NASA's looking at future uses, but that won't be decided for a little while," Larson said.

Even if Deep Impact's days are numbered, it can go out with its head held high, according to NASA officials. The extended mission was relatively affordable compared to other missions, said Ed Weiler, associate administrator at NASA's Science Mission Directorate. That $45 million price tag is about 10 percent of what it would have cost to launch a whole new mission.

"In these hard economic times, that's a really good deal," Weiler said.

NASA's broad EPOXI mission has been using the Deep Impact spacecraft to track and study various celestial objects. The name "EPOXI" is derived from the mission's dual science investigations — the Extrasolar Planet Observation and Characterization (EPOCh) and Deep Impact Extended Investigations (DIXI).

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Photos: Month in Space: January 2014

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  1. Southern stargazing

    Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them. (Y. Beletsky / ESO) Back to slideshow navigation
  2. A balloon's view

    Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June. The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich. (Kyle Moroney / AP) Back to slideshow navigation
  3. Spacemen at work

    Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment. (NASA) Back to slideshow navigation
  4. Special delivery

    The International Space Station's Canadian-built robotic arm moves toward Orbital Sciences Corp.'s Cygnus autonomous cargo craft as it approaches the station for a Jan. 12 delivery. The mountains below are the southwestern Alps. (NASA) Back to slideshow navigation
  5. Accidental art

    A piece of art? A time-lapse photo? A flickering light show? At first glance, this image looks nothing like the images we're used to seeing from the Hubble Space Telescope. But it's a genuine Hubble frame that was released on Jan. 27. Hubble's team suspects that the telescope's Fine Guidance System locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in a remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288. (NASA / ESA) Back to slideshow navigation
  6. Supersonic test flight

    A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

    More about SpaceShipTwo on PhotoBlog (Virgin Galactic) Back to slideshow navigation
  7. Red lagoon

    The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes. (ESO/VPHAS team) Back to slideshow navigation
  8. Fire on the mountain

    This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people. (NASA via AP) Back to slideshow navigation
  9. Where stars are born

    An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues. (NASA / JPL-Caltech) Back to slideshow navigation
  10. Cygnus takes flight

    Orbital Sciences Corp.'s Antares rocket rises from NASA's Wallops Flight Facility on Wallops Island, Va, on Jan. 9. The rocket sent Orbital's Cygnus cargo capsule on its first official resupply mission to the International Space Station. (Chris Perry / NASA) Back to slideshow navigation
  11. A long, long time ago...

    This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang. (NASA / NASA via AFP - Getty Images) Back to slideshow navigation
  12. Frosty halo

    Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill.

    Slideshow: The Year in Space (Brian Peterson / The Bismarck Tribune via AP) Back to slideshow navigation
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