NASA’s MESSENGER spacecraft will execute the second of three planned Mercury flybys on Monday, as it loops through the inner solar system on a trajectory that will take it into orbit around that planet in 2011.

MESSENGER image of Mercury. Source: NASA/Johns Hopkins University Applied Physics Laboratory/Arizona State University/Carnegie Institution of Washington

Mercury has been relatively scantily studied up until now because it is so close to the Sun and it is very difficult to get there. Only one spacecraft, Mariner 10, has flown by it before before — three passes back in 1974 and 1975.

What we know about the planet is that its surface is heavily cratered, with plains formed by volcanic eruptions. It has an extremely thin atmosphere. It is a place of temperature extremes: 840 degrees Fahrenheit during the day, -275 degrees at night. It is only about 43 million miles from the Sun — so from the surface of Mercury, the Sun would appear about two and a half times as large in the sky as it does on Earth. It revolves around the Sun once every 59 Earth days, and rotates on its axis very slowly…once every 176 Earth days. So on Mercury, a day is longer than 2 of Mercury’s years!

The first MESSENGER flyby occurred on January 14. The probe sent back pictures of approximately 20% of the surface that had never been photographed before. Monday’s flyby will have the spacecraft passing just 125 miles above the surface. The overarching goals of the mission are to photograph the planet in its entirety, and to learn more about its composition, structure, and magnetic field.

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

7PM UPDATE:  NASA just held a teleconference for reporters to discuss the Hubble mission delay.  The basic facts we gave you earlier in the day still hold up.  The part that has failed is called the Control Unit/Science Data Formatter.  There is a replacement part housed at the Goddard Space Flight Center, where Hubble operations are based.  The Hubble team will be putting that part through a series of tests to make sure it is operational and ready to fly, and they say they are confident it will pass.   If all goes as planned, Atlantis could be ready to fly by mid-February.

The Hubble Space Telescope. Source: NASA

In the mean time, the Space Shuttle Program will be making forward plans over the next couple of weeks.  Most likely, they will decide to remove the Hubble payload from Atlantis and eventually roll that shuttle back to the Vehicle Assembly Building.  Endeavour would then move to launch pad 39A and could be ready to launch as soon as November 14.

4PM UPDATE:    NASA has confirmed the launch will be delayed.   A new launch date has not been announced, but it will likely slip to January or February 2009.

Regarding the malfunctioning computer on the telescope: for an unknown reason, the principal channel on the on-board scientific data download system stopped working over the weekend.  Efforts to troubleshoot the problem have failed.  Later this week, telescope operators will try to activate a redundant downlink channel.  That “B-side” channel has never been switched on in orbit — it was last activated during ground tests in the late 1980’s or early 1990.  Even it it works, the computer system will be left without redundancy.  Scientists and engineers will need time to study the problem, and determine whether that system can be replaced during the upcoming mission.  It would also take time for engineers to configure replacement hardware for flight, and for astronauts to train for a removal and replacement task.

Sources tell CNN the space shuttle Atlantis mission to conduct the fifth and final servicing mission for the Hubble Space Telescope will very likely  be delayed until early next year.

An additional technical problem has cropped up with the telescope’s on-board scientific data downlink computer. Scientists and engineers will need time to study the problem, and determine whether additional repair tasks will be added to the mission.

Atlantis has been targeted for launch October 14. The next shuttle mission in the queue is a shuttle Endeavour mission to the International Space Station. It is currently targeted for launch on November 16.

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

NASA’s Stardust sample return capsule is set to go on display next week at the Smithsonian’s Air and Space Museum in Washington - giving the public their first chance to see the only man-made object to ever travel beyond the moon into the solar system and then return to Earth.

The goal of the Stardust mission was to return particles of dust from a comet to Earth.  Comets are icy debris left over from the formation of the solar system 4.5 billion years ago, and scientists were itching for a sample to study.  Comets pass by Earth regularly on long, elliptical orbits of the sun, so it would not be that difficult to send a spacecraft on an intercept course.  But getting a sample back…well, that was the challenge.  And engineers came up with an audacious plan.

After launching in 1999, the spacecraft looped through the solar system on a long rendezvous course with comet Wild 2 (pronounced Vild-2).  In January 2004, Stardust  passed through its tail, just 150 miles from its nucleus, and extended a tennis-racket shaped collector filled with a substance called aerogel.  Aerogel is an extremely light, soft, porous material that was used as a capture media for the tiny dust grains from the comet.

Once the sample was safely on board, Stardust turned for home.  On January 15, 2006, the spacecraft shot past Earth and jettisoned the sample return capsule with pinpoint accuracy.  It hit the atmosphere going nearly 29 thousand miles per hour,  rocketed across the sky over the Northern Pacific Ocean, the U.S. Pacific Northwest, and finally parachuted to landing on the empty salt flats of the Utah Test and Training Range.

Check out this SUPER COOL MOVIE of the re-entry shot from a NASA DC8 Aircraft.

Final odometer reading for the sample return capsule:  three billion miles.

Mission scientists say the samples have been a bonanza.  They had expected to find a lot of material in the comet’s tail that originally formed around other stars (hence the name Stardust), but this has turned out to be only a minor component.    What they have found is a mixture of crystalline minerals that they believe were formed at different times in the history of the solar system and at  temperature extremes.  Some of the icy components come from the extreme edges of the solar system  where comets spend most of their time.  But other material was apparently formed deep in the super-hot inner regions of the primordial solar system and was then ejected out beyond the orbit of Neptune.   They have detected particles of a material called Inti (named after the Incan sun god)  that is thought to be the earliest solid material formed in the solar system.

While the sample return capsule will now be showcased in the Smithsonian, the Stardust mother ship is still in space and recently got a new assignment.  The mission is called Stardust-NExT and will revisit comet 9P/Tempel 1, which was the focus of NASA’s Deep Impact Mission back in 2005.  That comet has since rounded the Sun, and the goal of Stardust-NExT will be to see how the close approach to our fiery star has altered it.

Kate Tobin, Sr. Producer, CNN Science & Tech

The Mars rover Opportunity has a new destination - it’s turning its wheels southeast and heading for a massive crater called “Endeavour.”

The small crater in the upper left corner is Victoria. Opportunity is located nearby. The rover will be heading southeast toward the massive Endeavour Crater. This image was taken by NASA’s Mars Odyssey Spacecraft. Credit: NASA/JPL/ASU

Opportunity departed Victoria Crater late last month after spending about two years rolling around the rim and studying rock formations just inside.

Endeavour is nearly 14 miles wide and 1000 feet deep, many times larger than Victoria, and features a far thicker stack of exposed layered rocks than those studied to date. Opportunity will have to traverse about seven miles across the Martian plain to reach it, doubling the total distance the rover has put on its odometer since landing back in 2004.

Mission managers admit the trip is going to be a long haul, and the aging rover may never get there.   But if it does, the scientific pay-off, not to mention the pictures, should be spectacular.

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

Check out this cool picture from the Phoenix Mars Lander of sunrise in the Martian Arctic.

Sunrise on Mars, August 25, 2008. Source: NASA/JPL-Caltech/University of Arizona/Texas A&M University

Scientists picked a landing location on the Arctic plains because data from orbiting Odyssey spacecraft indicated lots of water ice in the area, mostly in the form of permafrost.  The researchers figured that would be a good place to look for organic chemicals in the dirt and ice. Up until now, Phoenix, which landed May 25,  has been going about its business in the “land of the midnight sun” located deep inside the Martian Arctic Circle.

But now there is a hint of autumn in the air.  On August 21, the 86^th day after Phoenix landed, the sun set for the first time this season — rising again about half an hour later.  Now the days will get shorter and the nights longer until the sun finally sets for the season later this fall.

NASA has extended the Phoenix Lander’s mission through September, and will almost certainly do so again.  Eventually, the cold and dark of winter will set in, ice sheets will advance, and Phoenix will die a frigid death — probably some time in November.

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

After spending nearly a year exploring the inside of the massive Victoria Crater, the Mars rover Opportunity is on to the next task.

Cape Verde outcropping inside the Victoria Crater. Source: NASA

I’ve followed the journeys of the twin rovers since the beginning (they touched down on Mars about three weeks apart back in January 2004). I know I shouldn’t pick favorites, but I’ve always been partial to Opportunity…something about those layered rocks in the Eagle Crater landing site really drew my eye. And of course, Opportunity was the rover that found hard evidence that a salty sea once lapped the shores of Meridiani Planum.

But back on September 11, 2007, when Opportunity began a long drive down a slippery slope into Victoria Crater, I thought it might starting what would turn out to be a one-way trip. Mission operators back here on Earth were so careful with the drive down, stopping after short distances and backing up to assess traction on the path. And the crater was half a mile wide and over 200 feet deep, with what looked to me like a soft floor - complete with sand dunes!

I should have known the science team wouldn’t take any foolish chances…

Here’s what they did: they drove part way down the slope and identified a 20 foot tall cliff on the crater rim called “Cape Verde.” They backed the rover off several yards and took their time gathering high resolution images of the layered rock face. Analysis suggests the rocks were deposited by wind and altered over time by groundwater.

And with that, Opportunity headed for the exit. Turns out those treacherous-looking sand dunes at the bottom of the crater are of little scientific interest, and, in the words of principal investigator Steve Squyres, probably a “permanent rover trap.”

Next up: the rover will study loose, fist-sized rocks called “cobbles” that are littering the plains around the craters that have been Opportunity’s main focus up to now. The cobbles were likely formed when asteroids or comets hit Mars to form those craters, throwing up rocks and debris.

The rover is showing some signs of age. A “shoulder joint” in its robotic arm has a degraded motor, so the engineers have stopped stowing the arm, even when the rover is driving. By keeping it deployed all the time, they hope to keep it at least partially functional even if that motor eventually fails completely. And Opportunity’s left front wheel is showing signs of distress. It could fail in a manner similar to Spirit’s right front wheel, which locked up back in 2006.

What’s up with Spirit anyway? Over on the other side of Mars, that rover has been parked for the winter in a relatively sunny spot called “Home Plate” in the Columbia Hills. Even with the broken wheel, Spirit can still move around as long as the terrain is not too rugged. When Spring arrives in a few months, mission scientists plan to explore some bright, silica-rich soil nearby that could have been formed by hot water.

–Kate Tobin, Senior Producer, CNN Science & Technology

In a set-back to NASA’s efforts to fly the successor to the space shuttle sooner rather than later, the space agency announced a launch slip Monday for Orion, the next generation manned spacecraft currently under development.

Ares V rocket launches as part of the Constellation Program. Source: NASA

“September 2014 is when we are saying we will launch the first crew on the Orion,” said program manager Jeff Hanley during a conference call to brief reporters on the delay.

Cost concerns are at the root of the slip - as well as giving themselves wiggle room to deal with the unforeseen technical problems that will inevitably crop up.

“It’s the unknown unknowns that we have to hedge against,” said Hanley. “Having some number of months of schedule flexibility to meet our commitment, in addition to having some number of months of cost — dollars — flexibility, is key to keeping ourselves in a healthy posture.”

NASA officials plan to wrap up assembly of the International Space Station and retire the space shuttle fleet in 2010, freeing up money to build and fly the new spacecraft. Sometimes called “Apollo on steroids,” Orion is designed to ferry astronauts to and from the ISS, and eventually to the moon. Unlike the space shuttle, which lands like an airplane, Orion is a capsule that will parachute to a landing at Edwards Air Force Base in California.

The new September 2014 date is actually a self-imposed, internal deadline for NASA — the true commitment date for the first flight as set by Congress is March 2015. NASA managers were hoping to fly the new vehicle much sooner than that to keep the gap between the last shuttle flight and the first Orion flight to a minimum. Most recently, September 2013 was NASA’s goal. But program managers now admit that target date is unachievable.

“As we looked at the plan we had for Sept. 2013 against the available dollars it became clear to us that we needed to adjust our schedules,” said Hanley.

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

Well they’re not moon shoes, but a new device called the iShoe developed by an MIT graduate student may have your grandmother channeling her inner astronaut.

Lieberman demonstrates how sensors on the iShoe insole can diagnose balance problems.

That’s because Erez Lieberman and researchers at the Harvard-MIT Division of Health Sciences and Technology are designing new sensory insoles that may soon help doctors diagnose balance problems in senior citizens before major falls occur.

It’s based on a technology astronauts now use every time they return to earth, and one that Lieberman himself helped develop while an intern at NASA.

“The problem NASA faces is that the altered-gravity environment of spaceflight messes with the astronaut’s sense of balance,” says Lieberman, “[This technology] is currently being used to evaluate astronaut balance after return from zero-G.”

Lieberman and the iShoe team are now testing a new version of the technology; one that can help the elderly by analyzing pressure distribution on their feet.

“If we flag the existence of the problem early, a doctor or physical therapist can come in and make a better determination of the causes,” says Lieberman, “We can detect all kinds of effects. If a patient closes their eyes, our insole will know.”

With more than 250,000 Americans breaking their hips each year during major falls and 1-in-4 dying within a year of their injury, the device would be a welcome help to doctors, patients, and their families. In fact, it was his grandmother’s death after a fall that first inspired Lieberman to apply the NASA technology to senior citizens.

In the future, Lieberman hopes that iShoe will be equipped with technology that would help correct a patient’s balance issue as it occurs. It could even sound an alert when a fall occurs.

“Eventually we hope to provide subtle auditory and vibrational cues which will help the person adjust their balance. These cues will help them stand up straight and walk around confidently,” Lieberman says.

The iShoe team expects their product to be on the market with in two years.

– Julia Griffin, CNN Science & Technology

Scientists who focus their time on the Red Planet cheerfully call themselves “Martians”.  Well, it turns out these “Martians” know their turf well - and  have hit some pay dirt in the Arctic region of the Fourth Rock from the Sun. Mars Odyssey spotted the telltale signs of water ice beneath the surface from orbit a few years ago. It was that finding that helped the Martians choose a landing site for Phoenix.

Image: NASA/JPL-Caltech/University of Arizona/Texas A&M University/SSV

And from the moment they touched down, they saw the tantalizing signs that the ice was there - just a few inches beneath the rusty regolith. The dozen pulsed rocket thrusters cleared off a spot that was clearly white. Could it be ice? No way to dig right beneath Phoenix - but the once the arm and shovel got to work making some shallow trenches, it didn’t take long to find that white subsurface once again.

But was it the cool find Principal Investigator Peter Smith and his team at the University of Arizona had hoped for? Or was it something else?

But then something telling happened. Some dice-sized white crumbs disappeared from one of the trenches over the course of a few days. What could or would disappear like that?

You guessed it. Water ice. It doesn’t melt there (way too cold for that), but it does sublimate (go straight from solid to gas) in the wispy atmosphere of Mars.

So now the team just has to grab some of those “dice” before they sublimate - and toss them into the oven on Phoenix’ deck - and see what is inside. Could there be some organic material frozen inside? If so, that would be a big piece of evidence that there was (or maybe even is) life on Mars. I guess it all comes down to a roll of the “dice”.

- Miles O’Brien/CNN Space Correspondent

Discovery glided to a perfect landing under blue skies at the Kennedy Space Center in Florida today.    Commander Mark Kelly put her down right on the center line of Runway 15 at the Shuttle Landing Facility, wrapping up a 5,332,723 million mile journey that began on May 31.  During their two week visit to space, they installed the main component of the Japanese Kibo Laboratory onto the orbiting outpost.

This was:

-the 123rd shuttle flight

-the 35th flight of Discovery

-the 26th shuttle mission to the International Space Station

-the 10th post post-Columbia mission

-The 98th post-Challenger mission

-There will be 10 more missions before the fleet is retired in 2010

Mark your calendars for the next shuttle mission, currently targeted to launch October 8.  Astronauts will pay a final visit to the Hubble Space Telescope to switch out stabiizing gyroscopes and install  some new instruments that will hopefully keep the Hubble operational into the next decade.

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