BY JUSTIN RAY

Follow the preparations and launch of Boeing's Delta 4 rocket carrying the Air Force's DSCS 3-B6 communications satellite. Reload this page for the very latest on the mission.

THURSDAY, AUGUST 28, 2003

The weather forecast for Friday's launch attempt is available here.

2050 GMT (4:50 p.m. EDT)

Tomorrow's launch window extends from 7:13 to 8:31 p.m. EDT (2313-0031 GMT). Watch this page for live updates throughout the countdown.

2038 GMT (4:38 p.m. EDT)

Launch Weather Officer Joel Tumbiolo is predicting a 70 percent chance of acceptable conditions tomorrow. The tropical wave causing the weather trouble today is expected to move westward over the next 24 hours.

2031 GMT (4:31 p.m. EDT)

SCRUB. Faced with an approaching thunderstorm from the Atlantic Ocean, officials have cancelled this evening's attempt to launch the Boeing Delta 4 rocket carrying the final DSCS communications satellite for the U.S. Air Force.

The storm, packing gusty winds and heavy rain, is the second of the day that will send workers to the launch pad to move the protective mobile service tower around the Delta 4 for shielding from the inclement conditions at Cape Canaveral.

The tower was moved into its launch position 100 yards from the rocket just before lunchtime today. But an hour later, a thunderstorm prompted Boeing managers to return the tower to its location enclosing the vehicle.

That storm had a maximum gust of 29 knots at the pad. But it cleared and the tower was once again retracted for launch.

Although countdown activities were significantly delayed during the early afternoon hours while waiting for the weather to improve, the launch team was pressing forward to get the rocket fueled and airborne during the evening's 77-minute launch window.

But Delta 4 will not fly today. Worried that the next storm approaching will violate the rule governing the strength of wind that the rocket is allowed to endure while exposed on the pad, officials called a scrub.

Another launch attempt is being tentatively targeted for tomorrow evening.

2029 GMT (4:29 p.m. EDT)

Launch Weather Officer Joel Tumbiolo says he cannot say with certainity whether the storm will bring winds above the 29-knot limit to the pad. It appears to be weakening somewhat.

2029 GMT (4:29 p.m. EDT)

Officials are getting another weather update before making the "go/no go" decision whether to continue with the countdown.

2011 GMT (4:11 p.m. EDT)

Launch Weather Officer Joel Tumbiolo and Boeing Mission Director Rich Murphy are discussing the thunderstorm offshore. Although the radar shows that the storm is shrinking in size, it still has a powerful core.

The worry is if winds will exceed 28.6 knots at the pad when the storm hits the Cape. That is the pre-set rule for the vehicle being exposed on the pad. If officials think the winds will be higher than that, they will have to get the protective mobile service tower back around the vehicle.

So the storm is being monitored closely. A decision is expected within 20 minutes.

2007 GMT (4:07 p.m. EDT)

The Blast Danger Area has been verified cleared. And with that, the initial "go" has been given to prepare for liquid oxygen loading into the Delta 4 rocket.

The plan is to perform the vehicle chilldown operations and to load 50 percent of the liquid oxygen. Pending weather, the rocket will be fully loaded.

Liquid hydrogen fueling operations are still ahead, too.

2000 GMT (4:00 p.m. EDT)

Launch Weather Officer Joel Tumbiolo has provided an update on that thunderstorm over the Atlantic Ocean and headed toward the Cape. Earlier, the radar indicated that the squall was dissipating. However, now it is looking much more impressive. The leading edge is about 20 nautical miles away while the main core is about 40 miles out.

Tumbiolo predicts that the storm will bring wind and rain to the Cape but for a relatively short period of time over an hour from now. Behind this squall, the radar looks clear.

The winds during today's earlier storm at the Cape average between the mid-20s and low-30 knot range. The strongest gust at the pad was 29 knots. Tumbiolo expects similar conditions from the approaching storm.

Meanwhile, the countdown rolls on. RF link tests were just performed to verify the proper flow of telemetry data.

1941 GMT (3:41 p.m. EDT)

The chilldown conditioning of the liquid oxygen pump has been reported complete by the launch team. This is a milestone in preparation for loading the super-cold cryogenic oxidizer into the the Delta 4 rocket this afternoon.

However, fueling operations cannot begin until the pad area is cleared of all workers. Crews are still securing Complex 37 following rollback of the mobile service tower a little while ago.

1928 GMT (3:28 p.m. EDT)

T-minus 3 hours, 30 minutes and counting. Despite the weather delays today, the countdown clocks are still ticking as planned. The count has a planned 15-minute hold at the T-minus 5 minutes, leading to the opening of this evening's 77-minute launch window at 7:13 p.m. EDT.

The mobile service tower has been rolled back, initial preps for fueling operations are underway and engineers have been turning on the vehicle's avionics.

1920 GMT (3:20 p.m. EDT)

Launch Weather Officer Joel Tumbiolo reports conditions are continuing to improve at the Cape following the passage of a thunderstorm cell about an hour ago.

There is another squall over the Atlantic that is heading our way. The leading edge is about 40 nautical miles to the southeast and moving to the northwest at 20 knots. It appears to be dissipating somewhat. If it were to hold together, it is still a couple hours away. In any event, Tumbiolo says that storm is not as intense as the earlier one.

There are several launch weather rules currently being violated by the clouds overhead. But it is expected those conditions will be clearing.

"I am feeling more confident that we will, in fact, be going green on several of these (rules) as we get further along in the count," Tumbiolo said.

"As far as hazardous weather, I think we are in pretty good shape now."

1905 GMT (3:05 p.m. EDT)

The mobile service tower is in motion.

It was moved into the launch position earlier this morning. But the need to protect the Delta 4 rocket from bad weather, the structure was moved back around the vehicle. Now, it is heading away from the rocket for continuation of the count.

1901 GMT (3:01 p.m. EDT)

The entire launch team has been polled to verify everyone is ready to resume countdown operations. No constraints were reported.

Despite the several-hour impact to the countdown activities because of thunderstorms at the Cape, the launch team will progress through their procedures in support of liftoff during this evening's window of 7:13 to 8:30 p.m. EDT.

At pad 37B, workers are readying to roll the mobile service tower into the launch position shortly.

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

The launch team shortly will be briefed on the game plan for proceeding this afternoon.

1823 GMT (2:23 p.m. EDT)

Launch Weather Officer Joel Tumbiolo has just offered an update to mission managers on the current conditions. He reports that the worst is now over. The gusty winds and heavy rain have passed through the Cape area.

The strongest wind gust at pad 37B was 29 knots; the strongest at Cape Canaveral Air Force Station as a whole was 35 knots.

A Phase 2 lightning advisory remains in effect for the Cape. It is believed that will be downgraded to a Phase 1 shortly.

The next thunderstorm squall is about 60 miles to the southeast, over the Atlantic Ocean. Meteorologists are tracking its evolution and but indicate it is too hard to say whether it will hold together by the time it would reach the Cape. It is currently moving at about 20 knots and would arrive in about three hours.

1750 GMT (1:50 p.m. EDT)

The Cape is currently being pounded by this thunderstorm cell.

1743 GMT (1:43 p.m. EDT)

T-minus 5 hours, 15 minutes. The countdown continues to tick at rainy Cape Canaveral Air Force Station for this evening's scheduled launch of the Boeing Delta 4 rocket with the last DSCS communications satellite for the Pentagon.

Stormy weather has forced Boeing to roll the mobile service tower back around the rocket to shield the vehicle from the winds and rain.

Pending a "go" call from the weather team later this afternoon, the tower will be retracted for launch once again. The launch team can then resume the sequence of countdown activities leading to fueling the rocket with super-cold liquid hydrogen and liquid oxygen propellants.

Today's available launch window extends from 7:13 to 8:30 p.m. EDT.

1725 GMT (1:25 p.m. EDT)

Launch Weather Officer Joel Tumbiolo says the worst of the weather associated with the thunderstorm cell moving through the Cape area should be clear of the pad in the next half hour.

1713 GMT (1:13 p.m. EDT)

T-minus 5 hours, 45 minutes and counting! The Terminal Countdown has begun for today's launch of the Boeing Delta 4 rocket. With one planned hold at T-minus 5 minutes, liftoff is still targeted to occur at 7:13 p.m. EDT.

Pre-launch preparations are presently on hold due to approaching bad weather at Cape Canaveral. The protective service tower has been returned to its position enclosing the Delta 4 while the rain falls and winds gust at the pad.

Once the weather clears, the tower will be moved back to its parked position for launch so that fueling operations can commence this afternoon.

1655 GMT (12:55 p.m. EDT)

With thunderstorms approaching the Cape from the south, workers at pad 37B are rolling the mobile service tower back into position around the Delta 4 rocket for protection. The hope is the storms will pass through quickly enough to permit the tower to be return to its launch position this afternoon and allow the rocket to fly this evening as planned.

1540 GMT (11:40 a.m. EDT)

The 330-foot tall mobile service tower is slowly rolling away from the Boeing Delta 4 rocket at Cape Canaveral's launch pad 37B in preparation for this evening's liftoff to place a military communications satellite into Earth orbit.

The wheeled structure moves along European-style rail tracks to its launch position about the length of a football field from the rocket's mount.

The 9-million pound tower shields the Delta 4 from the weather, provides workers 360-degree access to the various areas on the vehicle and is needed to hoist the payload atop the upper stage during the launch campaign. The tower is 90-feet wide and 40-feet deep.

Once the tower is fully retracted, crews will secure the complex for launch before leaving the danger area around the pad. All workers must be clear of the area in preparation for the start of hazardous operations, including fueling the vehicle later this afternoon.

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

Meteorologists are expecting the weather to cooperate with today's launch of the Boeing Delta 4 rocket carrying the Air Force DSCS 3-B6 spacecraft. See the latest launch weather forecast here.

0001 GMT (8:01 p.m. EDT Wed.)

The last of the Air Force's DSCS communications satellites will ride Boeing's Delta 4 rocket into space Thursday evening from Cape Canaveral. Launch is targeted for 7:13 p.m. EDT (2313 GMT) at the opening of a 77-minute window that extends to 8:30 p.m. EDT (0030 GMT).

At Complex 37B Thursday morning, crews will roll the mobile service tower away from the Delta 4 rocket and secure the pad for liftoff. The Terminal Count will commence at 1:13 p.m.

The two-stage Delta 4-Medium vehicle with no strap-on solid boosters, valued at roughly $75 million according to the Air Force, will deploy the $210 million DSCS spacecraft into geosynchronous transfer orbit about 42 minutes after liftoff.

The satellite will joining the orbiting DSCS constellation that forms a worldwide communications relay network. DSCS satellites, built by Lockheed Martin, provide anti-jam, beyond line-of-sight communications to tanks in the Army, ships in the Navy and aircraft for the Air Force, as well as services for the president and secretary of defense.

This will be the second Air Force Evolved Expendable Launch Vehicle program mission. It follows the successful inaugural flight in March when the Delta 4 lofted another DSCS spacecraft.

The Pentagon created the EELV program in the 1990s to field cheaper and more reliable next-generation rockets to carry the government's satellite cargos into orbit, replacing the heritage Atlas, Delta and Titan vehicles.

Boeing developed the Delta 4 and Lockheed Martin designed its Atlas 5 under the EELV competition.

Watch this page for live countdown updates starting with tower rollback Thursday morning.

WEDNESDAY, AUGUST 27, 2003
1730 GMT (1:30 p.m. EDT)

The weather forecast is still favorable for tomorrow's launch of the Delta 4 rocket with DSCS. See the latest forecast here.

TUESDAY, AUGUST 26, 2003

Delayed nearly a month after technical troubles pushed the mission out of the Cape Canaveral launch lineup, the third Boeing Delta 4 rocket is set for liftoff Thursday evening.

The day's available launch window extends from 7:13 to 8:30 p.m. EDT (2313-0030 GMT).

The rocket will place the U.S. military's DSCS B6 communications spacecraft into geosynchronous transfer orbit at the completion of a 42-minute flight.

The early weather forecast looks promising with an 80 percent chance of favorable conditions. See the full forecast here.

THURSDAY, AUGUST 7, 2003

Unless the Eastern Range schedule at Cape Canaveral has an unexpected opening in the coming days, launch of Boeing's Delta 4 rocket carrying the last Air Force DSCS communications satellite will be delayed until August 28, the company said today.

The Air Force-controlled Range provides the required safety, tracking and communication services for all Cape rocket flights. The network handles one launch or significant test at a time before needing to be reconfigured to support the next event.

The Range is currently booked with tests in advance of the Titan 4 rocket launch with a classified national security payload. That liftoff will occur sometime between 11:40 p.m. August 17 and 5 a.m. August 18.

Launch of NASA's Space Infrared Telescope Facility aboard a Boeing Delta 2 rocket then has the Range for liftoff August 23. If the Delta 2 flight goes before the Delta 4, the SIRTF mission will take the distinction of being the 300th Delta launch.

A Boeing spokeswoman said engineers are keeping the Delta 4 rocket ready to fly on relatively short notice in case the Range should become available before the end of the month.

But as it stands today, the Delta 4's mission is being retargeted for August 28, with back-up attempts on August 29 and 30. Those dates have been requested from the Range. However, the Range has not officially allocated them on the schedule.

Officials say the troublesome Flight Termination System antenna on the Delta 4 rocket, which caused the launch to be delayed beyond the time frame originally booked on the Range, has been successfully removed and replaced.

MONDAY, AUGUST 4, 2003
1715 GMT (1:15 p.m. EDT)

When the Delta 4 rocket will get its next shot at launching remains very unclear because the Eastern Range's schedule is jam-packed this month.

Operated by the Air Force, the Range provides the required safety, tracking and communication services for all Cape rocket flights. The vast network can only handle one launch or significant test at a time.

As it stands today -- and, of course, anything can change -- the Range is booked with pre-launch testing starting this week that is mostly associated with the upcoming Titan 4 rocket flight. That liftoff is scheduled between 11:40 p.m. EDT August 17 and 5 a.m. EDT August 18 carrying a classified cargo for the National Reconnaissance Office. The Titan's back-up launch opportunity has the Range booked through August 20.

The Range would then reconfigure its systems to support the launch of Boeing's smaller Delta 2 rocket carrying NASA's Space Infrared Telescope Facility on August 23. The SIRTF mission has back-up launch attempts on August 24 and 25.

Boeing and the Air Force are working to assess when the Delta 4 can be rescheduled. At this time, no official date has been set.

The Delta 4 had August 3, 4 and 5 on the Range. But those dates were passed up to perform thermal protection system tests and the need to replace an antenna on the rocket.

SATURDAY, AUGUST 2, 2003
2120 GMT (5:20 p.m. EDT)

DELAY. Launch of the Boeing Delta 4 rocket carrying the DSCS 3-B6 communications satellite for the U.S. military is being delayed a few more days so workers can replace an antenna on the vehicle's safety-destruct system.

The Flight Termination System would be employed to destroy the rocket if it veers off course or experiences a major problem during launch.

A new launch date has not been established. But the liftoff from Cape Canaveral is not expected before Wednesday.

Officials will be working with the Air Force-controlled Eastern Range to schedule another launch attempt. The Range provides the required safety, tracking and communication services for all Cape rocket flights.

Meanwhile, testing of the rocket's thermal protection system has been completed successfully. Boeing said that issue was resolved today following lab tests with the adhesive used to hold silicon-based insulation to the bottom of the rocket. The tests were ordered to verify the adhesive was strong enough.

1630 GMT (12:30 p.m. EDT)

The latest version of the launch weather forecast is available here.

FRIDAY, AUGUST 1, 2003
2330 GMT (7:30 p.m. EDT)

Engineers are expected to complete a series of tests later tonight on thermal protection material used by the Boeing Delta 4 rocket, giving senior officials the data to decide if launch can occur Monday evening from Cape Canaveral.

The issue, which pushed back the liftoff from Sunday, is associated with the RTV adhesive that holds a silicon-based insulation to the bottom of the rocket.

Concerns were raised about the time it takes for the adhesive to "set up" after being applied to the rocket and how quickly the insulation should be affixed before the adhesive begins to lose strength.

Qualification tests are being re-performed in California to determine if the adhesive will retain enough strength to properly hold the insulation after being allowed to "set up" for the longest period of time it could have been on the rocket before the insulation was installed.

"By running this test, we'll have assured ourselves that we've qualified the worst case we could possibly have," explained Dan Collins, manager of Boeing's Delta programs.

The insulation covers the conical-shaped area at the base of the vehicle that houses the inner workings of the RS-68 main engine.

Launch has been tentatively retargeted for 6:59 p.m. EDT (2259 GMT) Monday from pad 37B at Cape Canaveral Air Force Station. But a further delay could be required.

"We are going to make sure we do it right. We will see what the tests tell us," said Collins.

If the tests reveal a concern with the insulation on the Delta 4 rocket as it currently stands on the pad, Collins said the material will be replaced.

"The only place where this is a question is in a few higher-strain areas. We would just have to remove what is there and replace it with cork. And that would take us a couple of days."

With the knowledge gained from testing, managers will decide by Saturday afternoon if the Delta 4 is ready to fly or if repairs are necessary.

The Launch Readiness Review between Boeing and the Air Force to give final approval to proceed with the countdown will occur on the day prior to liftoff.

The Air Force's Defense Satellite Communications System 3-B6 spacecraft will ride the Boeing-built rocket into Earth orbit during this 300th Delta launch.

1600 GMT (12:00 p.m. EDT)

The updated weather forecast for Monday's launch opportunity calls for a 60 percent chance of unfavorable conditions. See the full forecast here.

THURSDAY, JULY 31, 2003
2255 GMT (6:55 p.m. EDT)

Sunday's scheduled launch of the Boeing Delta 4 rocket from Cape Canaveral is being delayed 24 hours to give engineers time to complete tests of thermal protection material on the vehicle. Liftoff is tentatively reset for Monday.

Specific details about the material involved and the location on the rocket weren't immediately announced.

1600 GMT (12:00 p.m. EDT)

Launch Weather Officer Joel Tumbiolo has issued his initial forecast for Sunday's planned liftoff of the Boeing Delta 4 rocket. He is calling for a 60 percent chance of weather scrubbing the launch attempt. See the full forecast here.

TUESDAY, JULY 29, 2003

This weekend's launch from Cape Canaveral will mark a moment in history for the Delta rocket and the finale for a long-running family of U.S. military communications satellites.

The 300th Delta rocket is poised for blastoff Sunday carrying the 65th and last spacecraft for the Defense Satellite Communications System.

Launch from pad 37B will occur during a window of 6:58 to 8:21 p.m. EDT (2258-0021 GMT). Forty-two minutes after liftoff, the two-stage, all-cryogenic rocket will complete its mission by deploying the DSCS 3-B6 satellite into geosynchronous transfer orbit.

Read our complete launch preview story.

And watch this page for live updates during Sunday's countdown and launch.