Follow the countdown and launch of the Air Force Titan 2 rocket carrying the DMSP F16 weather satellite. Reload this page for the very latest on the mission.

2039 GMT (4:39 p.m. EDT)

Launch of the Titan 2 launch has been pushed back until at least Saturday while engineers perform additional analysis on the rocket's Inertial Measurement Unit guidance computer. A glitch was noted during the countdown, prompting officials to scrub today's launch attempt.

Further management meetings are planned on Friday to determine if the issue can be resolved for a liftoff Saturday at 1617 GMT (9:17 a.m. local time; 12:17 p.m. EDT) from Vandenberg Air Force Base's Space Launch Complex-4 West.

The weekend weather forecast calls for a vast improvement in viewing conditions at Vandenberg after days of foggy skies. But an increase in winds has decreased the odds of launching to 60 percent.

"The Great Basin High centered over the Four Corners dominates the weather pattern on Saturday," Launch Weather Officer Lt. Breea Lemm reported today. "The ridge of the high extends into the LA Basin, pushing the upper-level moisture up over the ridge and keeping skies over SLC-4W mostly clear, with some cirrus between 30,000 and 32,000 ft. At the surface, off shore flow will prevent marine layer formation, but radiational fog will decrease visibilities in the early morning hours. Winds expected to be 10-15 kts from the southwest and warm temperatures result from the weak Santa Ana set-up. Temperatures will be in the low to mid 60's, with upper level winds 35 knots from the southwest at 40,000 ft. No precipitation is expected to occur."

The winds are a concern for violating the rules governing acceptable weather conditions while rolling the mobile service tower away from the rocket and at launch time.

In the event launch slips to Sunday, there is again a 60 percent chance of favorable weather. The winds remain the prime worry.

"Sunday's weather shows the upper-level ridge continuing to push its way into the region," Lemm said. "Upper level moisture will continue to flow over the ridge and the cirrus layer will be scattered from 30,000 to 35,000 ft. Off shore flow at the surface will keep the marine layer at bay, with the thermal trough axis over SLC-4W pushing through from 1200 to 1800 (GMT) winds will shift from an easterly to northeasterly direction, once again from 10-15 kts. Upper level winds will be southwesterly, reaching a maximum of 30 knots near 35,000 feet. Temperatures will be in the upper 50's to low 60's, with no precipitation expected."

1556 GMT (11:56 a.m. EDT)

The final launch of a Titan 2 booster, a converted Intercontinental Ballistic Missile, was scrubbed this morning due to concerns with the rocket's Inertial Measurement Unit guidance computer.

Officials will meet later today to determine how to resolve the problem and decide when the launch can be rescheduled.

When it finally does fly, the Titan 2 will loft a U.S. military weather satellite. The $450 million mission has been delayed since January 2001 by an assortment of technical difficulties.

1544 GMT (11:44 a.m. EDT)

The mobile service tower is now being moved back into position around the Titan 2. It was retracted to the launch position earlier this morning. The tower encloses the rocket during its stay on the launch pad, providing workers access to all areas of the vehicle.

We are still standing by for official word from the Air Force with details on the problem that scrubbed today's countdown.

1512 GMT (11:12 a.m. EDT)

Post-scrub activities are continuing at Vandenberg following this morning's decision to postpone the launch of the Titan 2 rocket carrying the Defense Meteorological Satellite Program F16 spacecraft. The "go" has been given to start preparations for rolling the mobile service tower back around the rocket.

The launch weather officer has just verified that conditions are acceptable for moving the tower. Winds are currently calm.

1445 GMT (10:45 a.m. EDT)

We're awaiting further details from the Air Force on the nature of this problem that scrubbed today's launch of the Titan 2 rocket. A concern with an Inertial Measurement Unit was being reviewed by mission managers this morning. However, it wasn't clear if the IMU in question was on the launch vehicle or spacecraft. An IMU is in the guidance system.

A new launch date has not been established. "Future actions are to be determined," launch team members were told.

1438 GMT (10:38 a.m. EDT)

SCRUB! Today's launch attempt has been scrubbed, the Air Force just announced. There is no immediate word on when the next try will occur.

1431 GMT (10:31 a.m. EDT)

A problem resolution team is being formed to review an issue with the Inertial Measurement Unit.

1417 GMT (10:17 a.m. EDT)

Launch is now two hours away. The final Titan 2 rocket, a refurbished Intercontinental Ballistic Missile, will boost the Defense Meteorological Satellite Program F16 spacecraft to space from Vandenberg Air Force Base in California. The weather satellite will orbit 458 miles Earth as part of the DMSP constellation, replacing an older craft deployed in 1999.

"DMSP is in its fourth decade of service and continues to be an invaluable resource for successfully planning, executing and protecting military operations on land, at sea and in the air," said Col. Randy Odle, the system program director.

"Once operational F16 will deliver unparalleled global weather and space environmental information in support of users worldwide," Odle said. "F16 will be the best DMSP satellite ever launched."

The satellite is the first to carry a larger, more sophisticated package of sensors and instruments known as the Block 5D3 upgrade.

"We believe (the sensors) are going to provide a lot more capabilities once calibrated. Their calibration effort will go for about 18 months beyond the launch date to fully calibrate these new science and information sensors. We believe those will help improve our models and certainly help improve forecasting and the weather capability support to the warfighters and other users," Odle said.

"The time has come to unleash F16's tremendous potential. Let's make it so!"

1347 GMT (9:47 a.m. EDT)

T-minus 2 hours, 30 minutes.

1334 GMT (9:34 a.m. EDT)

The tower is nearing the park position where workers secure it in place as the countdown continues.

1328 GMT (9:28 a.m. EDT)

The mobile service tower is now clear of the rocket as it wheels back to the launch position.

The 200-foot tall mobile service tower is a massive wheeled structure that serves as a rocket assembly building and cocoon-like shelter for the Titan 2 vehicle at Space Launch Complex-4 West.

The tower provides the primary access and weather protection for the rocket while at the seaside pad overlooking the Pacific Ocean. It also has a 30-ton crane used to lift stages of the rocket and the satellite payload for stacking operations.

1315 GMT (9:15 a.m. EDT)

The "go" has been given to start rolling the mobile service tower away from the Titan 2 rocket for today's scheduled liftoff. An announcement at the launch pad has just told crews that the tower will begin moving at this time!

The structure takes about a half-hour to roll 180 feet away from the Titan 2.

1312 GMT (9:12 a.m. EDT)

Controllers report that all preparations to roll the mobile service tower have been completed. The structure should begin moving back from the Titan 2 shortly.

1247 GMT (8:47 a.m. EDT)

T-minus 3 hours, 30 minutes. The countdown continues this morning at Vandenberg Air Force Base in California for the launch of the final Titan 2 rocket. Crews at the launch pad are marching through the extremely long list of chores that have to be performed before the mobile service tower can be wheeled away from the rocket.

1227 GMT (8:27 a.m. EDT)

The launch weather officer has verified that all conditions are within limits for rolling back the mobile service tower this morning. Currently at the pad, winds are just two knots from the north-northwest at 340 degrees. The temperature is 53 degrees F.

For launch time, winds are expected to be 10 knots from 330 degrees. The temperature is forecast between 54 and 55 degrees F.

1205 GMT (8:05 a.m. EDT)

It is launch day for the Titan 2 rocket and DMSP F16 weather observatory for the U.S. Air Force. Liftoff is just over four hours away, with today's 10-minute launch window opening at 1617 GMT (9:17 a.m. local time; 12:17 p.m. EDT).

The mission has gotten this close to launch on three previous occassions -- January 20 and 21, 2001, and yesterday. Technical troubles spoiled each attempt.

Right now at the Space Launch Complex-4 West pad, preparations are underway to retract the mobile service tower away from the Titan 2 rocket. Workers are awaiting approval from mission managers to proceed with this milestone event in the countdown.

1845 GMT (2:45 p.m. EDT)

The weather forecast for Thursday's launch attempt calls for a 90 percent chance of acceptable conditions. The only minor concern is winds violating the limit during rollback of the mobile service tower and at launch time.

"The weather pattern for Thursday is still zonal aloft with the marine layer once again forming in the lower levels. Above the marine layer expect clear skies. The surface gradient tightens slightly, as a result surface winds will increase to 8-12 knots from the northwest. Upper level winds continue to flow from the west, reaching a maximum of 65 knots near 45,000 feet. Temperatures will remain in the upper 50's and low 60's, and no precipitation is expected," Launch Weather Officer Lt. Breea Lemm reported.

The forecast for Friday also predicts a 90 percent chance of meeting the weather rules. Winds are still the only threat.

"Friday's weather shows an upper-level ridge building in from the Pacific and with off shore flow at the lower levels the marine layer will stay mostly to the south, with only patches of marine layer over SLC-4W. Winds at the surface will be easterly from 8-12 knots. Upper level winds will be westerly, reaching a maximum of 70 knots near 45,000 feet. Temperatures will be in the mid to upper 50's, with no precipitation expected," Lemm said.

1645 GMT (12:45 p.m. EDT)

The Titan 2 rocket will try again Thursday to launch the Defense Meteorological Satellite Program F16 spacecraft on a $450 million mission to monitor weather conditions around the globe for U.S. military forces.

Today's countdown was scrubbed at sunrise after pre-launch activities fell behind schedule at the Space Launch Complex-4 West pad at Vandenberg Air force Base, California. While preparing to roll the mobile service tower away from the Titan 2, an air conditioning line feeding into the rocket's nose cone became unhooked, creating unplanned work in the busy countdown timeline.

"The launch this morning was delayed after an air conditioning duct became detached from the payload fairing. The duct is required to maintain environmental conditions for the satellite inside the fairing before launch," Lockheed Martin spokesman Evan McCollum said.

"After it became detached, they discovered that and technicians reattached it. But just before tower roll, it became detached again. By the time they were able do troubleshooting and reattach the duct, they determined there was not sufficient time remaining to do all the steps that would have to be done before launch."

With a launch window only 10 minutes long, officials had little margin to deal with countdown delays.

Officials aren't sure why the duct detached, but they expect the issue to be resolved in time to support another launch attempt on Thursday.

Liftoff is rescheduled for 9:17 a.m. local time (1617 GMT; 12:17 p.m. EDT). The window remains 10 minutes in length.

1435 GMT (10:35 a.m. EDT)

It will be another day before this hard-luck mission, running 33 months late because of technical troubles, will finally launch into space.

Today's planned flight of the last Titan 2 rocket carrying a U.S. Air Force weather satellite has been scrubbed after launch preparations fell behind schedule.

Liftoff is being re-targeted for 1617 GMT (9:17 a.m. local time, 12:17 p.m. EDT) Thursday from the Space Launch Complex-4 West pad at Vandenberg Air Force Base in California.

1430 GMT (10:30 a.m. EDT)

SCRUB! Today's launch attempt has been cancelled due to scheduling issues, the launch team was just told. Preparations at the pad had been running behind the timeline this morning. With only a 10-minute launch window available to get the Titan 2 rocket off the ground today to place the DMSP weather satellite into the proper orbit, time has run out for workers to get caught up and still make a 1617 GMT liftoff.

Plans are being put in place to try again tomorrow.

1424 GMT (10:24 a.m. EDT)

A problem resolution team is being formed to review the payload fairing air conditioning connections as the countdown goes forward.

1417 GMT (10:17 a.m. EDT)

T-minus 2 hours and counting. Workers at the launch pad report that the air duct has been reconnected. But there are still a lot of chores left to perform to get the complex configured for today's launch of the Titan 2 rocket.

1345 GMT (9:45 a.m. EDT)

Crews at Space Launch Complex-4 West are having to reconnect an air duct that came loose during launch preparations this morning. That unplanned work means activities to secure the launch pad for today's liftoff will be running behind schedule. However, liftoff is still scheduled for 1617 GMT.

1317 GMT (9:17 a.m. EDT)

T-minus 3 hours and counting. The Air Force- and Lockheed Martin-led launch team at Vandenberg Air Force Base continue moving through the countdown checklists this morning to ready the Titan 2 rocket, DMSP spacecraft and pad equipment for liftoff. Today's 10-minute launch window opens at 1617 GMT (9:17 a.m. local time; 12:17 p.m. EDT).

1249 GMT (8:49 a.m. EDT)

T-minus 3 hours, 28 minutes and counting. A data relay check has been completed with the P3 Orion telemetry relay aircraft supporting today's launch.

Flying over a downrange position in the Pacific Ocean, the aircraft will receive live telemetry data from the DMSP spacecraft during the apogee kick motor firing some 14 minutes after liftoff and send that information back to Vandenberg. The motor burn occurs outside of Vandenberg's tracking station coverage, and without the aircraft's support, officials would not be able to monitor in real-time the firing that will give the satellite the final boost needed to enter orbit.

1230 GMT (8:30 a.m. EDT)

At the Titan 2's launch pad -- Vandenberg's Space Launch Complex-4 West -- technicians are working through preparations to roll back the mobile service tower from around the rocket. Activities that are underway this morning include retracting the access platforms on the tower's various levels, opening the swing doors, securing tension lanyards, disconnecting security cables and checking the structure's rails to ensure they are free of debris in advance of the rollback.

1217 GMT (8:17 a.m. EDT)

The countdown is entering the final four hours for today's planned launch of the Titan 2 rocket and U.S. military weather satellite from Vandenberg Air Force Base in California. It will mark the final flight of Titan 2 and end a 33-month saga of delays for the Defense Meteorological Satellite Program F16 spacecraft.

It was January 2001 when DMSP F16 was this close to launch. On January 20, it reached T-minus 28 seconds before a glitch scrubbed the liftoff and began a long-running series of problems that have kept the mission grounded.

But officials hope today will finally be the day to get the DMSP F16 spacecraft into polar orbit where it will monitor global weather conditions for use in strategic and tactical planning by U.S. military forces deployed around the world.

"The time has come to unleash F16's tremendous potential. Let's make it so," said Col. Randy Odle, the DMSP system program director.


When the Titan 2 rocket blasts off Wednesday, it will bring to conclusion the decades-long program that began as a missile in the United States' arsenal against the Soviet Union, launched NASA's Gemini astronauts and in recent years carried smaller satellites into space. Read our full story.

1900 GMT (3:00 p.m. EDT)

The countdown is underway for tomorrow's launch of the final Titan 2 rocket on a long-delayed mission carrying a military weather satellite. Read our full story.

0401 GMT (12:01 a.m. EDT)

The Titan 2 rocket's 26-hour launch countdown begins this morning at Vandenberg Air Force Base for Wednesday's liftoff carrying a military weather satellite. Read our full story.


It is a rocket launch like no other. On the launch pad three times in the past three years, getting as close as 30 seconds from liftoff in early 2001, a $450 million military weather satellite mission could finally fly this week from California.

This story recaps the saga of the DMSP F16 satellite and the series of problems that have kept it grounded. Read the story here.


It was a half-minute away from blastoff 33 months ago. Now, a U.S. Air Force weather observatory is finally poised to leave its troubled history behind and rocket into space.

Launch of the Defense Meteorological Satellite Program F16 spacecraft atop a Titan 2 missile from Vandenberg Air Force Base in California is scheduled for 1617 GMT (12:17 p.m. EDT; 9:17 a.m. PDT) Wednesday. The day's available launch window extends for 10 minutes.

"The launch processing, from the satellite side, is going extremely well. We have essentially one more thing to do as a major processing event, and that is to pressurize our propulsion system to about 4,500 psi. We expect to do that Saturday," Col. Randy Odle, the DMSP system program director, said in an interview Thursday.

"We are looking forward to staying on schedule for the 15th of October, and everything that we are seeing today indicates that we can keep that schedule intact. We will keep our fingers crossed and hopefully at T-0 on the 15th at 9:17 (local time) we will see the spacecraft lift off from the pad."

A converted Cold War Titan 2 Intercontinental Ballistic Missile, originally built in the 1960s and stationed inside a Kansas silo from 1967 to 1986, will boost the satellite on its journey to orbit around Earth's poles.

The spacecraft will separate from the rocket's second stage six-and-a-half minutes after launch while on a sub-orbital trajectory above the Pacific Ocean. About seven minutes later, a kick motor attached to the satellite will ignite for a 51-second firing, boosting the craft into a stable, 421-by-460 nautical mile orbit. Ten seconds after the motor burns out, a 21-second orbit trim maneuver begins using the spacecraft's hydrazine-fueled thrusters to achieve the operational orbit circling 458 nautical miles above the planet.

The motor burn occurs after the satellite travels beyond the coverage zone of Vandenberg's tracking station. Therefore, two Navy P-3 telemetry relay aircraft have been requested to lend support by flying to downrange positions over the Pacific. One plane will monitor the firing, while the other will look at later spacecraft events.

The planes receive the spacecraft data and transmit the information back to Vandenberg. Without the P-3 support, officials cannot monitor the crucial rocket firing in real-time.

"For this mission, the P-3's are not mandatory. So we will not stop (the) launch because the P-3's were not available. But we would sure like them if at all possible," Odle said.

After a month-long checkout, the Lockheed Martin-built satellite is expected to be declared ready for service, replacing DMSP F15 as the primary spacecraft in the so-called "mid-morning orbit" of the DMSP constellation.

The DMSP F16 and Titan 2 launch vehicle have a combined value of $450 million, the Air Force said.

We will provide complete coverage of this launch over the next week. Watch this page on Monday for a comprehensive launch preview and a look back at the troubles that have plagued this mission. On Wednesday, live play-by-play updates on the countdown and launch will be posted right here. After liftoff, we'll wrap it up with a look at the satellite and the vital support it will provide military forces around the globe.


The U.S. Air Force is targeting October 15 for the long-delayed launch of its next polar-orbiting weather satellite atop a refurbished Titan 2 missile from Vandenberg Air Force Base, California. Read our full story.


A hard-luck military weather satellite has taken its place on the launch pad for the third time in nearly three years. This time, officials and workers alike hope the mission will finally blast skyward next month. Read our full story.

Saturn rockets
The conception, design, development, testing and launch history of the Saturn I and IB rocket is documented in this forthcoming three-disc DVD.

The ultimate Apollo 11 DVD
This exceptional chronicle of the historic Apollo 11 lunar landing mission features new digital transfers of film and television coverage unmatched by any other.

Apollo 8 leaves the cradle
NEW! The December 1968 journey of the Apollo 8 crew into lunar orbit is relived in this unique three-disc DVD set. Pre-order today and save!

Hubble Posters
Stunning posters featuring images from the Hubble Space Telescope and world-renowned astrophotographer David Malin are now available from the Astronomy Now Store.