BY JUSTIN RAY

Follow the landing of NASA's "Spirit" Mars Exploration Rover-A on the Red Planet! Reload this page for the very latest on the mission.

WEDNESDAY, JANUARY 7, 2004

More ultra-sharp views of the floor of Gusev Crater show a surprisingly rolling, rock-strewn landscape that bears little resemblance to the relatively smooth, wind-swept lakebed investigators thought they saw in initial, low-resolution images. Lakebed deposits may well be present, a mission scientist said today, but they may be more difficult to find than first thought. Read our full story.

1730 GMT (12:30 p.m. EST)

Rover mission control officials report that the high-gain antenna test performed during the Sol 4 workday at the landing site was successful. The current spikes seen previously when the antenna was being moved were not detected during the test. Engineers suspect the earlier situation was caused by debris or stickiness in motor housing.

Meanwhile, the additional airbag retraction was performed. However, further retraction is being planned for the upcoming Sol 5 to clear the deflated bag from the route Spirit will take when it drives off the lander next week.

Unlike the Sol 4 operation which simply used the retraction system to pull the bags a small amount, the upcoming "lift and tuck" attempt will raise the lander's left petal and activate the retraction mechanism. Afterward, the petal will be returned to the surface.

Additional imagery and science operations are planned for Sol 5, which begins at 8:14 p.m. EST (0114 GMT) tonight.

And although not formally planned, officials say if everything goes exceptionally well the first part of the rover's stand up procedures could occur on Sol 5.

1715 GMT (12:15 p.m. EST)

At the daily news conference currently underway at JPL, some images have been released.

Here is another color view of marks in the soil from the lander's airbag retraction.

For those of you with 3D glasses, check out the landing site in black-and-white with the panoramic camera.

TUESDAY, JANUARY 6, 2004

The sharpest picture ever taken on the surface of Mars was unveiled today, a remarkably detailed color mosaic showing the rock-strewn vista directly in front of the Spirit rover that stretches all the way to misty mesas and hills on the distant horizon. Read our full story.

2145 GMT (4:45 p.m. EST)

As we mentioned earlier this afternoon, President George W. Bush today offered his congratulations to the Spirit rover team for the successful landing.

At the White House daily news conference, Press Secretary Scott McClellan provided some additional details:

"The President today, on behalf of our nation, called to congratulate NASA Administrator Sean O'Keefe and the Jet Propulsion Laboratory team on the successful landing of the rover Spirit on Mars. The President thanked the NASA team for their hard work and ingenuity, and for reaffirming the great spirit of American exploration. The President shares in the excitement of all Americans as we see the dramatic images from Spirit's new home and we know that it is only a glimpse of the things to come as Spirit begins its historic trek across the Mars landscape.

"The President is strongly committed to the exploration of space, and thanks to the great work of those at NASA, America continues to be on the leading edge of exploration and discovery. I think the rover embodies the best of American ingenuity, technical know-how and can-do spirit."

McClellan was then asked by a reporter if President Bush had any new goals for the space program.

"There's no update to what the President has previously said and what I have previously said, that, as you are aware, in the aftermath of the tragic Columbia accident, the President asked -- or directed his administration to review our space policy, and that is where it stands," McClellan said.

"The review has been moving forward, and I have no additional update at this time."

2015 GMT (3:15 p.m. EST)

NASA today announced plans to name the landing site of the Mars Spirit Rover in honor of the astronauts who died in the tragic accident of the space shuttle Columbia in February. The area in the vast flatland of the Gusev Crater where Spirit landed this weekend will be called the Columbia Memorial Station. Read full story.

1900 GMT (2:00 p.m. EST)

After sleeping for 15 hours, Spirit was awakened at about 8:45 a.m. local time at Gusev Crater (last night Earth U.S. time) for Sol 3 activities. It made a 30-minute call to Mission Control to relay information about its health. Overnight, it had come alive a couple of times to make quick communications sessions with NASA's orbiting Mars Global Surveyor and Mars Odyssey spacecraft.

After looking through the health data, officials gave approval to perform the second in a series of cable cuts in preparation for the rover to stand up and deploy its wheels. These cables extend between the lander and Spirit rover.

One activity that had been planned for Sol 3 -- further retraction of the airbags -- was put off so additional testing could be performed on Earth. Controllers now plan to command the spacecraft to perform the retraction during the upcoming Sol 4 workday.

The base petal retraction system will pull in the deflated bags a total of three revolutions with 30-second breaks between. Afterward, another image of the lander will be taken to determine success. The bags are being rolled up further to permit a clearer pathway for the rover to drive off the lander.

Also in the upcoming day, commands will be sent to move the high-gain antenna up and down in a test to diagnose a possible problem. While moving the antenna on a previous day, current spikes were detected. This upcoming test will maneuver the antenna through the positions where the spikes were noted to see if the same situation is experienced.

Additional science imaging of the landing site will be performed on Sol 4, too.

The next mission update news conference is scheduled for 12 noon EST (1700 GMT) on Wednesday.

1755 GMT (12:55 p.m. EST)

This initial color "postcard" from Gusev Crater released today was snapped at 2:30 in the afternoon local time and took 20 minutes to acquire, officials say.

1740 GMT (12:40 p.m. EST)

If you wish to download a very large version of the color image, click here.

1734 GMT (12:34 p.m. EST)

Another close-up view shows the marks in the soil made by the lander's airbags during deflation and retraction. See it here.

1722 GMT (12:22 p.m. EST)

"This is just a tiny taste of what's to come," Steve Squyres, the rover science chief, says of the first color imagery released today.

1718 GMT (12:18 p.m. EST)

Another close-up view shows streaks in the martian soil, which scientists say reveal the direction of prevailing winds. See it here.

1712 GMT (12:12 p.m. EST)

A close-up view of the Mars terrain can be seen here.

1709 GMT (12:09 p.m. EST)

The first color picture is available here.

1705 GMT (12:05 p.m. EST)

"This is the day we have been waiting for," Jim Bell, the camera specialist for the rovers, says as the first color image from Spirit is unveiled! It shows the Martian surface directly in front of the lander.

1702 GMT (12:02 p.m. EST)

President Bush called the Spirit control team, congratulating them on the successful landing of the first Mars Exploration Rover. He said the landing was a proud moment for all Americans.

1600 GMT (11:00 a.m. EST)

NASA has planned a 12 noon EST (1700 GMT) news conference today to provide an update on the activities that occurred on Sol 3 and -- hopefully -- release of Spirit's first high-resolution color pictures.

MONDAY, JANUARY 5, 2004
2145 GMT (4:45 p.m. EST)

Four of the Spirit rovers critical scientific instruments sailed through initial checkout operations and a fifth will be tested late this evening, officials said today. A 3D panorama shot by Spirit's low-resolution navigation cameras was unveiled today and a full-resolution, color mosaic showing the terrain immediately in front of the rover is scheduled for downlink early Tuesday.

Read our complete story updating the progress of the Spirit rover mission.

1738 GMT (12:38 p.m. EST)

It appears that tonight's first good chance for receiving the pancam high-resolution color images will be approximately 3:30 a.m. EST via a communications pass when Mars Odyssey orbiter flies overhead the Spirit landing site.

Spirit is currently asleep in the Martian night. It is scheduled to awake for Sol 3 (day 3) around 7:10 p.m., mission officials are telling a news conference. The upcoming sol activities will include cutting a cable between the lander and rover, additional retraction of the airbags and some science-related operations.

1717 GMT (12:17 p.m. EST)

Squyres is telling the news conference that tiny thumbnails from the color mosaic have been received on Earth, confirming that Spirit has taken the first series of color images. However, the full images are still stored on the rover and not yet beamed to Earth. They could be transmitted tonight, but that will be determined by communications opportunities.

The first 3D black-and-white image, however, has been released showing the rover and landing area.

1715 GMT (12:15 p.m. EST)

Spirit rover's science leader, Steve Squyres, reports that the spacecraft's instruments were checked out successfully yesterday to confirm their health following landing.

1650 GMT (11:50 a.m. EST)

A press conference is about to begin at JPL to update the status of Spirit's mission. However, JPL says the color pancam postcard has not yet been relayed from the rover. The imagery could be received on Earth tonight.

0610 GMT (1:10 a.m. EST)

In another major milestone, the Spirit Mars rover's high-gain antenna was successfully deployed Sunday night and aimed at Earth. A few minutes before 12:30 a.m. EST today, the first direct-to-Earth communications session over the high-data-rate antenna began, prompting a now-familiar round of cheers and applause in Mission Control. Read our full story.

0557 GMT (12:57 a.m. EST)

Mars Odyssey orbiter will be making a pass over Spirit in a little while to relay more data back to Earth.

NASA has scheduled a 12 p.m. EST news conference at which time Spirit's first color imagery could be released.

To recap this evening's activities -- the rover's high-gain antenna was successfully deployed and used to relay data to Earth and receive commands from Mission Control. This main antenna is critical to efficiently carrying out Spirit's 90-day mission to explore Gusev Crater.

Also, the rover located the Sun in order to accurately determine Spirit's orientation on the surface for pointing its antenna to Earth.

One activity that is being delayed until tomorrow is cutting a no-longer-needed cable between the lander and rover. Time was running out in this day to complete the operation, officials said.

This day is officially called Sol 2. A "sol" is a Martian day, which lasts 24 hours, 39 minutes and 35 seconds. Sol 1 was landing day.

Watch this page for updates later Monday for news from the press briefing and the release of additional images.

0551 GMT (12:51 a.m. EST)

The first high-gain communications session has been completely successfully. In addition to engineering data received from Spirit, another batch of images has arrived on Earth.

0528 GMT (12:28 a.m. EST)

Mission Control has verified that it can now issue commands to Spirit through the high-gain antenna. This means the antenna system is working on both the send and receive modes.

0521 GMT (12:21 a.m. EST)

The high-gain antenna is working on the first attempt. Data is flowing directly from the rover to receiving stations on Earth. A strong signal is reported, and the antenna's pointing error is only two degrees off.

Things continue to progress very successfully for Mars Exploration Rover Spirit in the Gusev Crater.

0502 GMT (12:02 a.m. EST)

The Spirit rover's high-gain antenna has been unlocked and deployed, officials confirm! Shaped like a giant lollipop, this antenna on the top of the rover is the primary route for higher-speed communications from Spirit to Earth. The first use of the antenna to beam information to Mission Control is expected shortly.

0357 GMT (10:57 p.m. EST Sun.)

A scheduled news conference is about to begin at JPL. Further updates from Mission Control will resume at 12 a.m. EST tonight.

0335 GMT (10:35 p.m. EST Sun.)

Controllers report that the rover appears to have located the Sun's position in the sky. By knowing the Sun's location, the spacecraft's specific orientation on the surface can be determined and allow proper pointing of the high-gain antenna to face Earth. The so-called "Sun find" procedure called for the rover to tilt its camera package upward to look for the Sun.

Officials are still awaiting word on the high-gain antenna deployment sequence.

0321 GMT (10:21 p.m. EST Sun.)

This second low-gain antenna communications session is now underway between Spirit and Earth. Engineering data will be received from Spirit to verify how well the high-gain antenna deployment went and if procedures to locate the Sun has occurred.

0300 GMT (10:00 p.m. EST Sun.)

At the Jet Propulsion Laboratory tonight, controllers are awaiting data from Spirit to confirm the high-gain antenna deployment activities. Also, the rover will be finding the Sun overhead so the exact orientation and position of Spirit can be determined for pointing the high-gain antenna toward Earth.

And contrary to earlier information provided by JPL that said no communication was planned for the past few hours, Mission Control did conduct a low-gain antenna session.

SUNDAY, JANUARY 4, 2004
2300 GMT (6:00 p.m. EST)

The next communications session with Spirit will occur after 10 p.m. EST tonight. A NASA news conference will follow at 11 p.m.

2240 GMT (5:40 p.m. EST)

Good morning, Spirit!

The Mars Exploration Rover Spirit should be awakening for its first full day on the martian surface -- a day dedicated to deploying the craft's high-gain antenna and collecting the first color imagery.

To commemorate the wake up call, Mission Control just played the song "Good Morning, Good Morning" by the Beatles. This continues a tradition of hearing a tune to start the day for Mars landers.

"Welcome to Sol 2 at Gusev Crater," the flight director told his team in Mission Control. A "sol" is a Martian day, which lasts 24 hours, 39 minutes and 35 seconds. Sol 1 was landing day.

Spirit automatically comes to life once it senses enough power is being received via its solar panels. Sunrise at the landing site occurred about two hours ago.

2125 GMT (4:25 p.m. EST)

The primary goal of tonight's activity is to deploy, check out and begin using the rover's main high-gain antenna, the link flight controllers will use throughout the mission to send commands to the spacecraft. Overnight, scientists hope to downlink a spectacular color image from Spirit's high-resolution stereo panoramic camera. Read our full story.

2120 GMT (4:20 p.m. EST)

The Spirit Mars rover, currently asleep on the frigid surface of Mars, landed just six miles downrange from NASA's original target, a virtual bull's-eye that put the rover in the heart of a region scoured by scores of swirling dust devils. Read our full story.

2040 GMT (3:40 p.m. EST)

The next event for Mission Control is expected after 5:25 p.m. EST to mark Spirit's first "wake up call" on Mars to begin the first full day of surface operations.

2037 GMT (3:37 p.m. EST)

Earlier today the Mars Global Surveyor performed a maneuver to adjust its orbit to prepare for supporting communications relay with the Opportunity rover when it lands on the Red Planet January 25.

2033 GMT (3:33 p.m. EST)

After having some time to look at the data received via Odyssey, a poll of flight controllers confirmed that the rover remains in good condition.

2008 GMT (3:08 p.m. EST)

Mission Control reports that data from Spirit shows the landing site temperature is -98 degrees F.

The data playback from Odyssey includes not only engineering health information about the rover but also another batch of images.

1957 GMT (2:57 p.m. EST)

About 22.7 megabits of data has been received by Odyssey from the Spirit rover.

1950 GMT (2:50 p.m. EST)

It is still nighttime at Gusev Crater, and the Spirit rover is designed to power down during the darkness. But the craft comes to life when it has the opportunity to talk with NASA's orbiters.

Spirit woke up briefly to perform a data relay session with the Mars Odyssey orbiter as it sailed over the landing site from 2:29 to 2:45 p.m. EST. That data is expected on Earth shortly.

1830 GMT (1:30 p.m. EST)

By piecing together a mosaic from images taken by Spirit, an overhead view is created of the rover sitting on its lander in Gusev Crater. Better versions of these images are now available, so we are replacing the initial views we posted overnight. See the full image here. A closer view is available here.

FIRST LOOK AT THE IMAGES:
   SPIRIT'S VIEW OF THE MARTIAN HORIZON
   MARS ORBITER VIEW OF LANDING SITE
   FIRST IMAGES ON MISSION CONTROL SCREEN
   NASA CHIEF VIEWS EARLY IMAGES
   360-DEGREE OVERHEAD VIEW OF LANDING SITE
   SPIRIT ROVER SITTING ON ITS LANDER
   SCIENTISTS ADMIRE THE FIRST VIEWS
   DESCENT CAMERA IMAGE OF LANDING SITE

1738 GMT (12:38 p.m. EST)

NASA has released a new view, taken by Odyssey, that shows roughly where the lander descended. You can see craters in the lander's descent camera matching the second image from Odyssey. See them here.

The area is highlighted in this image.

1730 GMT (12:30 p.m. EST)

The Spirit rover is currently asleep in the Martian nighttime. It will be awakened a little later to begin a day of activities that includes deployment of its high-gain communications antenna. Also, health checks of the rover's science instruments will be conducted to ensure they have survived the landing. The first color images from the spacecraft are expected tonight.

It will be at least a week before Spirit drives off the lander to begin exploring the surface.

1650 GMT (11:50 a.m. EST)

The European Space Agency's Mars Express spacecraft performed another critical maneuver today, shrinking its orbit to get closer to the Red Planet's surface. Meanwhile, officials have vowed to continue the search to find the British Beagle 2 lander. For an update on these European spacecraft, see our status center.

SUNDAY, JANUARY 4, 2004
1020 GMT (5:20 a.m. EST)
A preliminary analysis of the 60 to 80 images relayed back to Earth from the Spirit rover during its initial communications session shows the lander bounced to stop in a near-perfect location to accomplish its scientific objectives.

"What a night!" said principal investigator Steve Squyres. "Spirit has shown us her new home in Gusev crater. It's a glorious place. It is a wonderful place from a scientific perspective in several different ways. First of all, not only have we landed at Gusev crater, but we now have the first evidence suggesting where we landed. We have hit what the science team believes to be the science sweet spot of Gusev crater."

Read our full story.

0925 GMT (4:25 a.m. EST)
NASA is planning a 12 p.m. EST (1700 GMT) news conference following a Mars Global Surveyor flight over the landing site that occurs about 90 minutes before.

0903 GMT (4:03 a.m. EST)
This image was captured by the descent camera on the lander just before the touchdown.

0854 GMT (3:54 a.m. EST)
The first color imagery from Spirit is expected Sunday evening, officials say.

0850 GMT (3:50 a.m. EST)
Here is a much larger version of the landing site image.

0840 GMT (3:40 a.m. EST)
Project scientist Steve Squyres speaking at a news conference right now says the landing site appears to be tailored-made for the Spirit rover. There are lots of rocks for good science but not too many to present a problem for the mobile geology laboratory.

"We are really going to be able to motor around."

0835 GMT (3:35 a.m. EST)
Cushioned by giant airbags, the Spirit rover bounced to a successful landing on Mars late Saturday and beamed back pictures from the surface three hours after touchdown. The black-and-white images showed Spirit landed on a rock-strewn plain, in a relatively level orientation facing south across the floor of Gusev crater, once the site of a vast lake.

For a thorough look back at tonight, see our full story.

0830 GMT (3:30 a.m. EST)
Here is a stunning initial view from Spirit showing the landscape of the Gusev Crater.

0815 GMT (3:15 a.m. EST)
The following is a statement from NASA Administrator Sean O'Keefe regarding the successful landing of the first Mars Excursion Rover, Spirit, on the Martian surface.

"Congratulations to the Mars Rover team on achieving a successful landing on the surface of Mars by the Rover Spirit. This amazing feat, coming so soon in the New Year, is a tribute to the dedication to the many men and women throughout NASA and our many partners who worked extremely hard to give our amazing rovers the best chance for success on their mission of exploration on the Red Planet.

"In a few weeks, Spirit's twin Opportunity will be landing on the other side of the planet. The rovers will soon begin their mission to search the rocks of Mars for signs that water may have been present for long periods of time -- signs that may tell us whether Mars could have been hospitable to life in the past."

0812 GMT (3:12 a.m. EST)
A press conference is scheduled for 3:30 a.m. EST to discuss the latest news on the spacecraft. We'll post an update as information becomes available.

0807 GMT (3:07 a.m. EST)
Flight controllers are currently looking through all of the engineering data relayed from the Spirit rover, via Mars Odyssey orbiter, back to Earth.

The only potential issue facing the team was an apparent short fall in electrical power output from the rover's solar panels. A controller reported the panels were generating 83 percent of the expected power.

0757 GMT (2:57 a.m. EST)
Here is an image of folks looking at the images in Mission Control.

0757 GMT (2:57 a.m. EST)
"It is not supposed to go this well!" someone just joked from Mission Control.

0754 GMT (2:54 a.m. EST)
Check out a 360-degree panorama of the landing site -- with the rover and its deployed solar panels in full view.

0753 GMT (2:53 a.m. EST)
The initial look at the landing site shows it has an assortment of rock sizes and a "drive-able" surface for the six-wheeled Spirit rover, according to Mission Control.

0749 GMT (2:49 a.m. EST)
Another image showing the rocky surface of Mars at the landing site is available here.

0744 GMT (2:44 a.m. EST)
"Welcome to Gusev Crater" a flight controller says.

0743 GMT (2:43 a.m. EST)
The lander is level on the surface, no major tilt is reported. The pan camera mast is deployed as planned.

0742 GMT (2:42 a.m. EST)
The images are being pieced together to create mosaics and a 360-degree view of the site.

0742 GMT (2:42 a.m. EST)
That large rock is situated to the rear of the rover.

0737 GMT (2:37 a.m. EST)
Check out some of the early images from Spirit as displayed in Mission Control. Click here.

0737 GMT (2:37 a.m. EST)
Another image is showing a very large rock right next to the lander.

0736 GMT (2:36 a.m. EST)
One of the images from the descent camera has been received. It shows the surface while the spacecraft was still falling toward the ground.

0734 GMT (2:34 a.m. EST)
Scientists and engineers are utterly ecstatic by the images from the Spirit rover sitting on the Gusev Crater on Mars.

The lander's petals are open, the rover's solar arrays are deployed and everything appears to be going very, very well.

0732 GMT (2:32 a.m. EST)
Multiple black and white images are being displayed in the control room.

0731 GMT (2:31 a.m. EST)
Flight controllers say there are no new software faults since earlier this evening when the last data came from Spirit.

0730 GMT (2:30 a.m. EST)
The first images of Spirit have arrived on planet Earth!

0730 GMT (2:30 a.m. EST)
Data is now flowing into the control room, prompting another round of applause.

0726 GMT (2:26 a.m. EST)
This data to be received in Mission Control will begin with engineering health information about the rover, to be followed by images from various cameras on Spirit.

0717 GMT (2:17 a.m. EST)
About 24 megabits of data is being played back from Odyssey. It will take about 12 minutes to get all the information, officials report. This will contain engineering data on the rover's systems and possibly some pictures.

0706 GMT (2:06 a.m. EST)
Applause has erupted in the control center again! Mission Control reports that data is being received from Spirit to Odyssey. That confirms the rover is operating properly in its post-landing activities.

0700 GMT (2:00 a.m. EST)
The Mars Odyssey spacecraft is currently flying over the landing site. It will serve as a relay to transmit data from Spirit to Earth.

"Earthset" has occurred -- meaning that Earth is no longer visible from landing site for tonight. "Earthrise" is 12:22 p.m. EST.

0622 GMT (1:22 a.m. EST)
A team will be reconstructing all of the entry, descent and landing data in the coming hours and days to ensure there were no serious problems. The second Mars Exploration Rover, Opportunity, is still to come -- with landing on the other side of the Red Planet on January 25.

But what is clear tonight, rover project manager Peter Theisinger says, "We know the design is solid."

0612 GMT (1:12 a.m. EST)
"When you walk outside today, if it is clear, you can see Mars. Just think, we just landed a rover on that planet. That is very sobering," JPL director Charles Elachi says.

0603 GMT (1:03 a.m. EST)
Peter Theisinger, the Mars Exploration Rover project manager, says there is a "good" chance that we will get the first pictures from Spirit tonight.

"I would stick around if I were you," he just told a press conference at JPL.

0555 GMT (12:55 a.m. EST)
Officials are reporting that everything appears to have gone by the book tonight. The jubilation continues...but a lot of work is ahead to get the Spirit rover configured and drive it on the Martian surface over the next week-and-a-half.

0536 GMT (12:36 a.m. EST)
O'Keefe and other program officials are having a toast to celebrate the Mars Exploration Rovers.

0534 GMT (12:34 a.m. EST)
"This is a big night for NASA. We are back!" agency administrator Sean O'Keefe just proclaimed at the post-landing news conference.

0524 GMT (12:24 a.m. EST)
By this point, the base petal should be finished retracting its airbags. It will take about 10 more minutes for the side petals to complete their bag retraction, Mission Control reports.

0505 GMT (12:05 a.m. EST)
NASA officials will be holding a post-landing press conference at 12:30 a.m. EST.

0500 GMT (12:00 a.m. EST)
With Spirit on the surface, it will use motors to retract the airbags. This operation could take an hour to complete. The lander then will open up like a flower, lowering its petals to reveal the rover tucked inside. Since Spirit has landed with its base petal down -- the best case scenario -- the opening will take less time.

Next, the rover will deploy its power-generating solar panels. It can begin taking some pictures of the landing site once the arrays are deployed. Those initial images, if snapped this evening, could be released by NASA within hours.

0455 GMT (11:55 p.m. EST)
The spacecraft has landed with its base petal down.

0453 GMT (11:53 p.m. EST)
The Mission Control room is a wild place at the moment with handshakes, screams and some very happy tears.

0452 GMT (11:52 p.m. EST)
SPIRIT IS ALIVE ON MARS! A "very strong signal" is now being received from the Spirit rover from the Gusev Crater on the surface of the Red Planet!

0451 GMT (11:51 p.m. EST)
The radio telescope at Stanford University reports it may have received signal from the lander at the time it would have been on the surface.

0450 GMT (11:50 p.m. EST)
Meanwhile, the controllers for the Mars Global Surveyor orbiter report they may have received data from Spirit after the planned landing time. The orbiter was flying over the landing site at the time of descent and touchdown.

0448 GMT (11:48 p.m. EST)
Spirit is scheduled to begin transmitting tones from the surface in one minute.

0445 GMT (11:45 p.m. EST)
Now 10 minutes after the touchdown on Mars, officials are still waiting for some signal from Spirit. The lander should have rolled to a stop by now.

0440 GMT (11:40 p.m. EST)
The wait is underway at the control center to hear further information from Spirit to confirm it has survived all of the bounces and come to a safe position on Mars.

0437 GMT (11:37 p.m. EST)
Now there is no signal from Spirit. Controllers received an initial indication that the craft was on the surface and bouncing. But that link has now been lost.

The bounces will continue for a few minutes and then the craft will roll up to a kilometer from its initial touch down point before coming to rest.

0436 GMT (11:36 p.m. EST)
Mission Control has received indications from the spacecraft that it is bouncing on the surface inside its airbags.

0436 GMT (11:36 p.m. EST)
SPIRIT IS BOUNCING ON MARS!

0435 GMT (11:35 p.m. EST)
Spirit should have inflated its airbags and fired retrorockets before impacting the Martian surface.

Airbags will cushion the landing that occurs at any moment.

"This is the fun part," Manning says. "The vehicle is designed for bouncing. The airbags do a great job of protecting the vehicle, coconing it over lots of complicated surfaces -- complicates rocks and terrain shapes. We are very confident these airbags will do a great job."

0434 GMT (11:34 p.m. EST)
"The heat shield has protected us but now we don't need it," Manning says "We have to undress ourselves. So the lander is now free to rappel down a 20-meter bridle. Once we are in this configuration, this is a great configuration to be in for the lander to both see the surface with a camera and to use a radar to detect its altitude.

"When we get to the right altitude, the airbags are inflated. Now we are ready to fire the retrorockets to bring the system to a dead stop from about 180 mph to zero about 12 meters above the ground.

"At this point we bounce and bounce and bounce. Just like Pathfinder, we will bounce maybe as much as a kilometer or more from where we let go of the bridle."

0434 GMT (11:34 p.m. EST)
No longer needed, the heat shield has been jettisoned, exposing the lander inside the descent module.

0434 GMT (11:34 p.m. EST)
Chute is out! Mission Control has detected indication of parachute deployment.

0433 GMT (11:33 p.m. EST)
Having slowed to 1,000 mph, the spacecraft will deploy its supersonic parachute at this point in the descent.

0431 GMT (11:31 p.m. EST)
Deceleration continues as the spacecraft plunges through the atmosphere.

0431 GMT (11:31 p.m. EST)
"The temperature just outside the heat shield gets very close, if not more, than the temperature of the surface of the Sun. It is very hot! Inside it stays relatively cool, it barely gets above room temperature," Rob Manning says of what the spacecraft should be experiencing during the entry.

0431 GMT (11:31 p.m. EST)
The Spirit lander is now transmitting a tone that tells Mission Control is it decelerating at one-to-three g's.

0430 GMT (11:30 p.m. EST)
Entry is a bit shallow, Mission Control reports. But that is "nominal."

0430 GMT (11:30 p.m. EST)
The navigation team reports they detect entry into the atmosphere. Altitude is 46 miles, traveling at Mach 27 at 12,175 mph.

0429 GMT (11:29 p.m. EST)
ENTRY INTERFACE. The "six minutes of hell" has begun! The Mars Exploration Rover is now hitting the top fringes of the Red Planet's atmosphere at over 12,000 miles per hour. Landing is six minutes away.

0428 GMT (11:28 p.m. EST)
Spirit is 121 miles above Mars, traveling at 12,084 mph.

0427 GMT (11:27 p.m. EST)
Altitude is 220 miles. Time to entry interface is two minutes.

0425 GMT (11:25 p.m. EST)
Spirit is cocooned with its descent module called the aeroshell. The aeroshell which has two parts -- a heat shield that faces forward and a backshell.

Here is an overview:

The system for getting each rover safely through Mars' atmosphere and onto the surface relies on an aeroshell, a parachute and airbags. The aeroshell has two parts: a heat shield that faces forward and a backshell. Both are based on designs used successfully by NASA's Viking Mars landers in 1976 and Mars Pathfinder in 1997.

The parachute is attached to the backshell and opens to about 15 meters (49 feet) in diameter. The parachute design was tested under simulated martian conditions in a large wind tunnel at NASA's Ames Research Center near Sunnyvale, Calif.

The backshell carries a deceleration meter used to determine the right moment for deploying the parachute. Solid-fuel rockets mounted on the underside of the shell reduce vertical velocity and any excessive horizontal velocity just before landing.

The airbags, based on Pathfinder's design, cushion the impact of the lander on the surface. Each of the four faces of the folded-up lander is equipped with an envelope of six airbags stitched together. Explosive gas generators rapidly inflate the airbags to a pressure of about 6900 Pascal (one pound per square inch). Each airbag has double bladders to support impact pressure and, to protect the bladders from sharp rocks, six layers of a special cloth woven from polymer fiber that is five times stronger than steel. The fiber material, Vectran, is used in the strings of archery bows and tennis racquets.

0424 GMT (11:24 p.m. EST)
Five minutes from entering the atmosphere. Spirit is now traveling at 11,300 mph, continuing to increase thanks to the pull of Martian gravity.

0422 GMT (11:22 p.m. EST)
A pre-entry poll of Mission Control has been completed with no significant issues.

0418 GMT (11:18 p.m. EST)
A low-gain antenna on the spacecraft's backshell is transmitting simple "tones" to give Earth some idea of its health during entry.

NASA says a dictionary of about 100 possible tones can provide information such as whether the cruise stage has separated, whether the parachute opens and whether the deceleration rate is within the expected range.

"Tones don't say a lot. Basically they tell us the spacecraft is healthy and is still happy in this phase of spinning along at two rpm until it hits the atmosphere," Manning says.

"At the time it hits the atmosphere, it will start detecting 'hey, we are slowing down'. The software will make a note of that and issues tones that let us know that the vehicle is decelerating. We should see those tones and see the deceleration."

0417 GMT (11:17 p.m. EST)
Spirit is 1,250 miles above the planet.

0416 GMT (11:16 p.m. EST)
The cruise stage has been jettisoned! It will ultimately impact Mars.

"It is the part of the vehicle that got us safely through cruise all the way to Mars," Rob Manning, the Entry, Descent and Landing development manager, says of the cruise stage.

"It has the power, the solar cells, thrusters and fuel tanks. It's done its job, we don't need it anymore. It falls away on a separate trajectory."

The descent module with the rover is now ready for entering the atmosphere about 13 minutes from now. "This is just a simple spinning bullet, rotating at about two revolutions per minute," Manning says.

0412 GMT (11:12 p.m. EST)
Following the earlier turn to entry orientation, the pointing appears close to perfect.

0410 GMT (11:10 p.m. EST)
Spirit is 2,000 miles above the planet and traveling at 9,470 mph.

0409 GMT (11:09 p.m. EST)
Spirit is now 20 minutes from entry interface.

Airbag engineers have determined the heater temperature situation is not going to be a problem. The temperature can be much warmer than the preset value that Mission Control was looking for.

0401 GMT (11:01 p.m. EST)
NASA Administrator Sean O'Keefe just took a walk through Mission Control to visit with the engineers before tonight's landing.

0355 GMT (10:55 p.m. EST)
Landing is now 40 minutes away.

The next major event will be separation between the no-longer-needed cruise stage from the descent module containing the Spirit rover. This jettison is scheduled for 11:14 p.m. EST.

Here is NASA's description of the cruise stage:

The cruise stage provides capabilities needed during the seven-month passage to Mars but not later in the mission, such as a propulsion system for trajectory correction maneuvers. Approximately 2.6 meters (8.5 feet) in diameter and 1.6 meters (5.2 feet) tall, the disc-shaped cruise stage is outfitted with solar panels and antennas on one face, and with fuel tanks and the aeroshell on the other. Around the rim sit thrusters, a star scanner and a Sun sensor.

The propulsion system uses hydrazine propellant stored in two titanium tanks. Since the the entire spacecraft spins at about 2 rotations per minute, fuel in the tanks is pushed outward toward outlets and through fuel lines to two clusters of thrusters. Each cluster has four thrusters pointing in different directions.

The star scanner and Sun sensor help the spacecraft determine its orientation. Since the rover's solar arrays are tucked away inside the aeroshell for the trip, the cruise stage needs its own for electrical energy. The arrays could generate more than 600 watts when the spacecraft was about as far from the Sun as Earth is, and generate about half that much as it nears Mars.

The cruise stage also carries a system for carrying excess heat away from the rover's computer with a pumped freon loop and rim-mounted radiators.

0351 GMT (10:51 p.m. EST)
The spacecraft is scheduled to be performing an activity to vent coolant. This venting will cause the spacecraft to wobble a bit, so tiny thrusters will be used to keep the lander on course for entry.

0350 GMT (10:50 p.m. EST)
Mission Control is watching the temperature from heaters that condition solid rockets used by gas generators aboard the lander. The generators inflate the impact-cushioning airbags moments before touchdown. The rate of increase indicates the temperature will reach the maximum limit by the time the heaters are switched off. Officials are assessing this situation.

Meanwhile, the Mars Global Surveyor and Mars Odyssey orbiters are verified in good shape. The spacecraft will be used for communications relay from Spirit.

0342 GMT (10:42 p.m. EST)
In about five minutes, a status check will be conducted inside Mission Control to verify the turn to entry attitude was completely successful.

0335 GMT (10:35 p.m. EST)
Landing of Spirit in the Gusev Crater of Mars is now just one hour away!

Mission Control reports the Spirit spacecraft is about 6,600 miles above Mars, traveling at a velocity of 7,700 miles per hour.

0330 GMT (10:30 p.m. EST)
With the solar panels of the cruise stage no longer pointed at the Sun, the Spirit rover is relying upon five onboard batteries until it is on the planet's surface and can deploy its own power-generating solar arrays.

0325 GMT (10:25 p.m. EST)
The turn to entry attitude for the spacecraft has been completed. This was a critical event prior to Spirit making the fiery plunge into the atmosphere by turning to put the heat shield facing the planet. Had the turn not occurred, the craft surely would burn up during entry.

0321 GMT (10:21 p.m. EST)
The spacecraft has about two degrees remaining in this turn.

0319 GMT (10:19 p.m. EST)
Mission Control reports the Spirit spacecraft is about 8,500 miles above Mars, traveling at a velocity of 7,500 miles per hour. Time to atmospheric entry is one hour and 10 minutes.

0314 GMT (10:14 p.m. EST)
The Canberra tracking station in Australia is locked on to the spacecraft's signal, which is 10 bits per second.

0310 GMT (10:10 p.m. EST)
This turn is estimated to take 14 to 20 minutes to complete.

0308 GMT (10:08 p.m. EST)
The rotation is confirmed to be underway by Mission Control.

0304 GMT (10:04 p.m. EST)
The turn to entry attitude is scheduled to begin now. This rotation will orient the spacecraft such that the heat shield is facing the atmosphere. Prior to this time, Spirit was flying with its cruise stage solar panels pointed at the Sun and communications antenna in line with Earth.

0230 GMT (9:30 p.m. EST)
At about this time the Spirit spacecraft's onboard software is scheduled to begin starting its processes for this evening's landing activities.

"Entry, descent and landing is something that is not controlled from Earth. We let the software onboard do all the jobs, all the steps, all the actions in real-time to control these actions very precisely," Rob Manning, the Entry, Descent and Landing development manager.

0135 GMT (8:35 p.m. EST)
NASA is now projecting the landing zone to be 39 miles long by 2 miles wide (62 by 3 kilometers).

Meanwhile, two changes have been made. Spirit will unfurl its parachute two seconds sooner than originally planned to compensate for current Martian weather conditions.

"A dust storm seen on the other side of the planet has caused global heating and thinning of the atmosphere at high altitudes," said Mark Adler, the rover mission manager for cruise and entry, descent and landing (EDL).

Late today, mission control moved up by 40 minutes the time when several pyrotechnical devices -- explosive bolts -- will be put into an "enabled" condition prior to firing. This change was made to ensure the enable commands are performed.

"These pyro devices will be fired to carry out necessary steps of descent and landing, such as deploying the parachute and jettisoning the heat shield," officials said.

0035 GMT (7:35 p.m. EST)
The landing of Spirit is now four hours away.

The next major event will occur at about 10:04 p.m. EST when the spacecraft performs a turn to position its heat shield facing the atmosphere. This will not only prepare for entry but also the jettison of the no-longer-needed cruise stage. Separation between the cruise stage and the descent module is expected around 11:14 p.m.

0015 GMT (7:15 p.m. EST)
Looking beyond the scientific knowledge to be gained from the Mars Exploration Rovers, NASA's space science chief Ed Weiler says the Spirit and Opportunity rovers could ignite a spark of interest in children to learn about space and engineering.

"This mission has the potential to really excite a lot of kids out there. We are in the Internet age now and broadband. We are putting out every image (from the rovers) on the Internet. Kids are going to be able to dial in the image of the day, image of the hour. They are going to be able to watch this rover go not five meters but up to a kilometer and hopefully at the end of the mission even farther.

"We are competing with GameBoys and X-Boxes and Game Cubes. This mission, if successful, has the potential of competing with those things, and get kids maybe a little bit excited about exploration and science again."

SATURDAY, JANUARY 3, 2004
2300 GMT (6:00 p.m. EST)
The Spirit rover's destination is the Gusev Crater of Mars that could have once held a lake. Getting to that specific region of the planet has required precision guidance on the 300-million mile voyage from Earth. Officials said this afternoon that Spirit is on course.

"The navigation is truly excellent. It is better than we could have possibly hoped for," said Louis D'Amario, the Mars Exploration Rover navigation team chief.

"The nav team's primary objective is to deliver the Spirit spacecraft to the desired landing point on Mars as accurately as possible."

The group has actively maneuvered the rover since its launch seven months ago, guiding its course across space. The last maneuver was a small one performed last Friday, which moved the target landing point about 33 miles.

"The Gusev Crater represents a very small area on Mars. It is only about 100 miles across. That area within the crater represents only 1/70th of one-percent of the total surface area of Mars. So you can see the navigation challenge to land Spirit in that crater is quite a challenge. But it is even more difficult than that because our requirement is not just to land in the crater, it is to land in a particular area in the crater that has been evaluated very carefully and determined to be safe for landings. That area within the crater is a cigar-shaped or elliptical area that is about 42 miles by 3 miles.

"To get Spirit into the crater and into the desired landing area, we have to control the trajectory between launch and arrival at Mars. We do that by executing what are called trajectory correction maneuvers. There were five opportunities for altering the flight path, plus one contingency opportunity -- the one we just cancelled (today).

"When you take into account how far we have traveled and what our target at Mars is, it is kind of like playing a par 5 hole in golf where you tee off in Paris and the hole is in Tokyo, with a little water hazard at the end!

"The nav team managed to get a birdie on this hole since we only took four maneuvers and we cancelled the fifth and the sixth. So we are doing very well."

D'Amario says there is a 99 percent probability of landing in the ellipse. His team projects Spirit will touch down about two miles from the center of the land zone.

"This is essentially perfect navigation...We are very happy."

2120 GMT (4:20 p.m. EST)
"I think today is a great day to land on Mars!" says Mark Adler, the rover mission manager for cruise and entry, descent and landing (EDL).

"We launched on June 10th of this year, about seven months ago, out of Cape Canaveral Air Force Station on a Boeing Delta 2 rocket. That rocket threw us on a trajectory to go approximately to Mars. In that last seven months we have been flying the spacecraft, maintaining its health, maintaining its power and doing small maneuvers to guide the spacecraft exactly to the landing site at Gusev Crater," Adler told a pre-landing news conference a short time ago.

"We have, last night, completed conditioning of the lander batteries to prepare them for coming online for supporting the entry and power after that point in time.

"Right, now the spacecraft health is excellent. We have good attitude -- keeping the solar panels pointed at the Sun and the antennas pointed at Earth. We have good power through the solar panels, good communications at 120 bps.

"The spacecraft is in EDL mode. It is prepared to run EDL software when it encounters the atmosphere, it is prepared to do a turn before EDL, it is also prepared to turn on the inertial measurement units and the heaters for the gas generators for the entry event."

Spirit enters the atmosphere at 11:29 p.m. EST (0429 GMT) tonight. If all goes well, the rover will touch down in the Gusev Crater at 11:35 p.m. EST (0435 GMT).

But NASA officials continue to remind the press and public that landing a robotic spacecraft on another planet has the potential for failure.

"We need to remember this is just one more step in the process of accomplishing this mission -- landing on Mars today. But it is by far the riskiest step in the process and of course the one we are most concerned about," said Peter Theisinger, the Mars Exploration Rover project manager.

"We are 43 months from the start of the project, and the team has worked extremely difficult problems and worked extremely hard and intensively to get to this day."

NASA has spent over $800 million on Spirit and its twin, Opportunity, that arrives at Mars later this month.

2005 GMT (3:05 p.m. EST)
At a news conference underway right now at the Jet Propulsion Laboratory, officials report that the Spirit rover is 59,000 miles from Mars and closing at a rate of 6,400 miles per hour.

The opportunity to perform a final trajectory correction maneuver today has been cancelled. Navigators report that the spacecraft's track is right on course.

1930 GMT (2:30 p.m. EST)
Mars Exploration Rover officials will be holding a status briefing for reporters at 3 p.m. EST today. We will provide an update shortly thereafter.

The Spirit rover remains set to land on Mars at 11:35 p.m. EST tonight!

FRIDAY, JANUARY 2, 2004
After a seven-month journey from Earth to Mars, the Spirit rover arrives at the Red Planet Saturday night with a tense six-minute descent to the surface.

Spirit is the first of two Mars Exploration Rovers launched by NASA to study the Martian surface like mobile geologists. The Opportunity rover lands on January 25.

"We have done everything humanly possible to make these missions successful. We have spent as much money as required, within reason. But in the last six minutes of hell -- that is the six minutes of entry, descent and landing, all it takes is a gust of wind at the wrong time or a rock in the wrong place and this mission could be over," said Ed Weiler, NASA's associate administrator for space science.

Before entering the atmosphere, the cruise stage must be jettisoned from the descent module containing the rover. This is scheduled for 11:14:20 p.m. EST.

Entry interface occurs at 11:29:20 p.m. EST as the spacecraft punches into the Martian atmosphere at 12,000 miles per hour. The protective heat shield is designed to withstand the 2,600-degree F temperature expected from the friction of the plunging into the atmosphere. Peak heating will happen around 11:31:05 p.m.

With about two minutes left in the descent, at 11:33:24 p.m., the parachute will be deployed to further slow the fall. Twenty seconds later, the bottom half of its aeroshell is jettisoned, exposing the lander. The top half of the shell, still riding the parachute, will lower the lander on a small tether.

The impact-cushioning airbags surrounding the lander will inflate at 11:35:11 p.m., followed a second later by ignition of retro rockets on the upper shell. The tether will be cut about 40 feet above the surface at 11:35:15 p.m. The first moment of touchdown -- starting a series of bounces -- is targeted for 11:35:17 p.m.

The spacecraft could roll a half-mile or more from its initial impact point before coming to rest.

Of 10 previous landers sent to Mars, six have failed, three have succeeded (Vikings and Pathfinder) and the fate of one (Beagle) is unclear. Many have dubbed Mars "the death planet" because of the difficulty getting probes there safely.

"Why is it worth that risk? Well, one of NASA's prime science goals is to conduct the search for life, attempt to find out if humans are alone in the universe. Mars is the closest place to look for life and it is the best place to look," Weiler says.

"Biologists have taught us in the last 20 years about water and its key to life...We know Mars has water -- it has ice on surface at the poles. What Odyssey has told us over the past two years is that not only is there ice at the surface at the poles, if you go above 60 degrees North (latitude) or below 60 degrees south, the first one-meter of soil is composed half, by volume, of water ice crystals. So water in the form of ice is abundant on Mars.

"It is a good place to look, it is a good place to start the search. But before we can begin that search, we have to land safely."

We will provide continuous updates on this page throughout the evening!

WEDNESDAY, DECEMBER 31, 2003
NASA's Mars Exploration Rover "Spirit" remains on course for arrival at the Red Planet Saturday night. Touchdown inside the Gusev Crater is expected at 11:35 p.m. EST (0435 GMT Sunday).

The spacecraft fired its thrusters for 3.4 seconds last Friday to perform a minor -- and potentially last -- course correction maneuver before its descent to the planet's surface. The engine firing changed the velocity of the spacecraft by only 25 millimeters per second (about one-twentieth of one mile per hour).

Radio tracking of the craft during the 24 hours after the maneuver showed it to be right on course for its landing, NASA said.

"The maneuver went flawlessly," said Dr. Mark Adler, Spirit mission manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

This was Spirit's fourth trajectory correction maneuver since launch on June 10. Two more are on the schedule for the flight's final three days, if needed.

"It seems unlikely we'll have to do a fifth trajectory correction maneuver, but we'll make the final call Thursday morning after we have a few more days of tracking data. Right now, it looks as though we hit the bull's-eye," Adler said earlier this week.

According to NASA, the adjustment was a quick nudge approximately perpendicular to the spacecraft's spin axis.

"It moved the arrival time later by two seconds and moved the landing point on the surface northeast by about 54 kilometers" (33 miles), said JPL's Chris Potts, deputy navigation team chief for the NASA Mars Exploration Rover project.

By tomorrow morning, Spirit will have traveled 481.9 million kilometers (299.4 million miles) since launch and have will have 5.1 million kilometers (3.2 million miles) left to go.

Watch this page for live updates of Spirit's landing on Mars!

Read our earlier launch coverage.