As previewed in a blog post from several days ago, the Cassini spacecraft executed another in a series of close flybys of Saturn's geyser moon Enceladus on Thursday.

Raw image of Saturn's moon Enceladus taken October 10 by the Cassini spacecraft. Source: NASA/JPL/Space Science Institute

The first images are now available, with more to follow in the coming days.

Cassini Imaging Team Leader Carolyn Porco reports that all went according to plan:  "Yesterday, Cassini executed another daring dive over the south polar region of Enceladus and through its plume of vapor and frost.  And once again, it went spectacularly well.   The imaging team acquired fabulous images, and the instruments designed to collect and measure the constituents of the plume for analysis did what they should."

I'll keep an eye out and post again when the science analysis comes out.  As noted earlier, there is another Enceladus flyby scheduled for October 31.

–Kate Tobin, Sr. Producer, CNN Science & Tech

Filed under: Astrobiology • Cassini • Enceladus • NASA • Space

Here are the first images from the MESSENGER spacecraft's Monday flyby of Mercury.

Image of craters on Mercury taken Oct. 6. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

MESSENGER will fly by the planet once more in September 2009. The spacecraft is scheduled to enter orbit around Mercury on March 18, 2011.

In the meantime, the Cassini spacecraft is getting ready to execute two more flybys of Saturn's moon Enceladus (pronounced in-SELL-uh-dus) this month. Enceladus, you may recall, is the moon that is spewing cold geysers of water into space, which suggests to scientists there is liquid water (possibly even an ocean) under its surface.

The first flyby, set for Thursday October 9th, is arguably the more exciting of the two. Cassini will pass just 16 miles over the surface of the moon, directly through the geyser plume. The emphasis on this flyby will be to use the on-board science instruments to learn more about its composition. Data from previous flybys indicate that, in addition to water vapor, water ice, and dust, the plume also contains trace amounts of organic chemicals. The presence of organics has certainly perked up the antennae of the astrobiology community. In only a short period of time this little moon has shot to near the top of the list of promising places to look for extra-terrestrial microbial life.

The second Enceladus flyby of the month is set for Oct. 31. Cassini will fly 122 miles over the surface, and use on-board cameras to photograph surface fractures in the south polar region.

–Kate Tobin, Sr. Producer, CNN Science & Technology

Filed under: Astrobiology • Cassini • Enceladus • Mercury • MESSENGER • NASA • Saturn • Space

Tuesday's communications glitch between Phoenix and the Mars Recon Orbiter is resolved, Phoenix Project Manager Barry Goldstein today reporters at today's press briefing.

”Fisheye” view of Phoenix Mars Lander looking down on itself. Source: NASA/JPL/Univ. of Arizona

Engineers designed Phoenix to use the two NASA satellites orbiting Mars as relay stations to send and receive data and commands with mission controllers. That relay link failed Tuesday morning when MRO experienced a radio transmission malfunction just as it was to send Phoenix its do-list for the day. The evening transmission went off without a hitch - but, while they sort out exactly what happened with MRO, project managers are going to use the other orbiter, Mars Odyssey, to do much of the communications heavy-lifting. Both satellites make at least two good passes over Phoenix every day, so the impact on the mission should be minimal.

In the mean time, the team is testing out Phoenix's robotic arm today and tomorrow, and if all goes well they'll start digging operations early next week. Phoenix is designed to dig down into the Martian dirt to scoop up soil and ice. The lander is equipped with a suite of instruments designed to look for organic chemicals frozen in that permafrost layer that may indicate whether or not Mars was once an hospitable place for life to have existed.

–Kate Tobin, Senior Producer, CNN Science & Technology

Filed under: Astrobiology • Mars • NASA • Space

The CNN team is on ground here in Pasadena, California, getting ready for the Mars landing tomorrow night. Ground zero for the action is the Jet Propulsion Laboratory, which is a unique NASA center in that it is a joint effort between the space agency and Caltech. There is also a contingency of scientists here from the University of Arizona, led by Mars Phoenix principal investigator Peter Smith. Assuming all goes well with the landing and the spacecraft is healthy, the science "mission control" for Phoenix will be run out of the Lunar and Planetary Lab in Tucson.

Mars Phoenix begins its fiery entry into Mars’ atmosphere. Source: NASA/JPL/Univ. of Arizona

The scientists and engineers who are overseeing tomorrow's entry, descent and landing will have their heads together in the coming hours to make some decisions about tweaking the spacecraft's final approach to Mars. They have two "trajectory correction manuever opportunities" remaining, one late tonight and another about noon Eastern time tomorrow. That means two chances to fire onboard rockets to subtly steer the spacecraft and put it on the optimal route toward the target landing site.

So, excitement is building as landing time draws near. Please do join us for an hour special around the landing Sunday night at 7pm Eastern//11pm GMT for our worldwide viewers. Miles O'Brien is anchoring and he'll be joined by special expert guest Dr. Steve Squyres of Cornell, whom you may know as lead scientist for the Spirit and Opportunity rovers.

Here's a little tick-tock of key events Sunday night (all times Eastern):

7:46pm Phoenix enters Mars’ atmosphere

7:53pm Phoenix lands

7:54pm Scheduled loss of communications (Phoenix will use the Mars Odyssey orbiter as a communications relay, and Odyssey will move out of range of the Deep Space Network almost immediately after Phoenix lands. Bummer.)

9:43pm Communications resume, first opportunity for images. If all goes well, watch for those images on CNN in the 10pm ET/2am GMT hour, with more to come on Monday morning.

–Kate Tobin, Senior Producer, CNN Science & Technology

Filed under: Astrobiology • Mars • NASA • Space

On Sunday, a few hours after the checkered flag signals the winner of the Indianapolis 500, a much, much longer trip will conclude: After a nine-month, roundabout 422 million mile journey from Earth, NASA's Phoenix Mars Lander will take aim at a site near the Martian North Pole.

Source: NASA/JPL/Univ. of Arizona

And like the fans at Indy, everyone will be waiting to see if there's a wreck.

Phoenix will enter the Martian atmosphere at 12,500 miles an hour. After deploying parachutes and firing thrusters, and at a speed of about 5.4 miles an hour, it will touch down at about 7:38pm Eastern Time. Or so NASA hopes. Mars landing craft have a roughly 50-50 success rate since the twin Viking landers touched down 32 years ago. With a communications delay of about 15 minutes, we'll get our first info on the landing status at 7:53pm ET.

CNN's Miles O'Brien will cover the landing live in a special hour broadcast beginning at 7pm ET. CNN International will carry the broadcast worldwide, featuring Miles's international counterpart, Kilometers O'Brien (sorry, it's an old joke around here......).

Later in the evening, around the 10pm hour, we hope to show the first images from Phoenix. Unlike the spectacularly successful Mars Rovers, Spirit and Opportunity, Phoenix is not a mobile craft. It's a digger.

Equipped with a small backhoe, Phoenix will dig into the Martian tundra in search of evidence of water, or other clues of past life on the Red Planet. Its predecessor in Martian Polar research, the Mars Polar Lander, was lost on landing in 1999.

Miles and CNN producers Kate Tobin and Alex Walker will broadcast the hour from NASA's Jet Propulsion Lab in Pasadena, California, mission control for the landing. They'll blog here to keep you updated - including after that tense moment at 7:53pm, when we learn whether a team of scientists and engineers will see years of work turn into a smashing success, or a smashup.

Next Saturday, the space scene shifts to the Kennedy Space Center, where the Shuttle Discovery is set to launch at 5:02pm ET on a mission to install a Japanese-built lab on the International Space Station, and to swap out ISS crew members. Miles will be live from KSC for the launch as well.

-Peter Dykstra, Executive Producer, CNN Science & Tech

Filed under: Astrobiology • European Space Agency • International Space Station • Mars • NASA • Space

That's what Cassini spacecraft scientists had to say about what's in those cold water geysers shooting off from the pole of Saturn's moon Enceladus (that's pronounced "in-SELL-uh-dus").

Jet Blue. Source: NASA/JPL/Space Science Institute

The Cassini team was stunned to discover the geysers two years ago when the probe made its first flyby of the tiny moon. Then on March 12th, they got another chance to point their science instruments at the billowing plume during another close approach, passing just 120 miles from the surface. This time the optical cameras took a back seat to a suite of spectrographs designed to "taste and smell" what chemicals are present.

The team has just announced the initial science findings. It turns out the jets are mostly water vapor, with some ice crystals mixed in. Also present are methane, carbon dioxide, carbon monoxide, and an abundance of both simple and complex organic chemicals.

Another instrument on board measured the temperatures at the fissures where the geysers erupt from the surface. Turns out it gets up to a hot and balmy -130 degrees Fahrenheit there. OK, that's pretty cold. But it is significantly warmer than the -300 degrees Fahrenheit temperatures elsewhere on that moon. The researchers say some sort of heat source deep within the planet must be at work, and that underground pockets of liquid water very likely exist - maybe even relatively close to the surface.

So what does it all mean? The moon has water, organic compounds, and a heat source...and that makes it a prime hunting ground for astrobiologists (scientists who look for signs of extraterrestrial life). They don't know at this point if that underground liquid water exists, and they certainly don't know if any sort of microbial life form may be living there. But you can bet they're excited about it!

Cassini will flyby Enceladus again in August.

–Kate Tobin, Senior Producer, CNN Science & Technology

Filed under: Astrobiology • Enceladus • NASA • Saturn • Space

The latest clue to finding life on Mars may have lot in common with the salt on your dining room table.

NASA’s Mars Odyssey orbiter has discovered evidence of salt deposits in 200 spots on the Red Planet, indicating that water was abundant in those places. Given the close connection between water and life on earth, these salt sites could be prime locations for proof of possible Martian life.

This false-color image shows a deposit of chloride (salt) minerals in blue in the southern highlands of Mars. Source: NASA/JPL-Caltech/Arizona State University/University of Hawaii

Odyssey’s Thermal Emission Imaging System snapped thousands of pictures in a range of wavelengths that helped scientists see evidence for salt. Only sites in the planet’s southern highlands, the most ancient rocks on Mars, appeared to contain chloride, a component of many kinds of salt.

The salt deposits formed about 3.5 to 3.9 billion years ago, at a time when Mars may have had sporadic spouts of a wetter and warmer climate than the conditions observed there today, which are cold and arid.

Images revealed many of the salt deposits in basins with channels leading into them, which is “consistent with water flowing in over a long time,” said Philip Christensen, principal investigator for the camera at Arizona State University, in a NASA statement.

The salt probably didn’t come from a global ocean, as the sites of the deposits are disconnected, said team leader Mikki Osterloo at the University of Hawaii in the statement. But groundwater coming up to the surface in low spots could have generated the chloride sites, he said.

Scientists trying to track down proof of life on Mars have largely followed clues of sulfates, which could result from the evaporation of water, and clays, which suggest weathering by water. Chloride now joins the mix of leads to follow for scientists seeking close encounters with remnants of past Martian life forms.

The researchers published their findings in a recent issue of Science, just days before the shake-up about a possible $4 million budget cut from NASA's Mars Exploration Rover program.

–Elizabeth Landau, Associate Producer, CNN.com

Filed under: Astrobiology • NASA • Space

Scientists working with the Hubble Space Telescope have identified large quantities of the organic chemical methane as well as water on a planet orbiting a distant star.

Artist's Rendering. Source: NASA, ESA, and G. Bacon (STScI)

Now that in-and-of-itself is not proof that life exists there. In fact, researchers say it almost certainly DOESN'T because the planet is orbiting very close to its "sun" and it therefore is much too hot (1700 degrees Fahrenheit) to support life.

But the new findings, published in this week's edition of the journal "Nature," do show that orbiting telescopes like Hubble and it's yet-to-be-launched successor called the James Webb Space Telescope can detect organic chemicals on far-off worlds. And on some of those (one in a thousand? million? billion?) the conditions may be right to support life.

Will we ever find one? Impossible to say. But the tools are there to begin the search.

The Jupiter-sized planet in question is called HD189733b, and is orbiting a star about 63 light years away from our solar system in the constellation Vulpecula.

Astronomers have found nearly 300 of these so-called "extrasolar" planets since the first one was confirmed in 1995. NASA has drawn up plans for space-based telescopes like the Terrestrial Planet Finder and the Space Interferometry Mission to specifically search for Earth-like planets outside our solar system. At this point, both of those programs have been postponed indefinitely due to budget issues.

–Kate Tobin, Senior Producer, CNN Science & Technology

Filed under: Astrobiology • extrasolar planets • Space

Where is it, you might ask??? Some astronomers say Mars, others claim it's Jupiter's moon Europa, and still others tout Titan, one of Saturn's satellites. 

Cassini Image

But recently a new candidate has entered the field: Saturn's moon Enceladus. That's pronounced "in-SELL-uh-duss." Two years ago the Cassini spacecraft, which is currently studying Saturn and its moons, flew by Enceladus and captured images and data showing Yellowstone-like geysers containing water erupting from the south pole. That, in turn, suggested pockets of liquid water, maybe even an ocean, may be lurking very near the surface. And, as any good astrobiology buff will tell you, wet places in the solar system will be the best places to look for extra-terrestrial microbial life. While there was no smoking gun, it sure got a lot of scientists' attention. And Enceladus shot to the top of the list of places we might want to know a lot more about.

On Wednesday, Cassini will make its closest flyby ever of Enceladus, flying just 30 miles above the moon's surface, eventually passing directly over that south polar plume. It is one a series of Enceladus flybys that Cassini will execute this year, and it will be the closest yet to any object in the Saturn system.

Instruments aboard the spacecraft will be able to determine what sort of other chemicals are in the geyser spray...which should help planetary scientists better figure out what's going on with this intriguing moon.

–Kate Tobin, Senior Producer, CNN Science & Technology

Filed under: Astrobiology • Space