BY JUSTIN RAY

Follow the countdown and launch of the Boeing Delta 2 rocket with the U.S. Air Force's GPS 2R-9 navigation spacecraft. Reload this page for the very latest on the mission.

2043 GMT (3:43 p.m. EST)

The launch team reports the loading of the Delta 2 rocket's first stage liquid oxygen tank was completed at 3:43:05 p.m. EST. The operation took 25 minutes and zero seconds today. The tank will be replenished through the countdown to replace the super-cold liquid oxygen that naturally boils away.

The rocket is now fully fueled for launch. The vehicle's first stage was successfully loaded with RP-1 kerosene fuel along with the liquid oxygen over the past hour. The second stage was filled with its storable nitrogen tetroxide and Aerozine 50 fuels a few days ago; the third stage and nine strap-on booster rockets are solid-propellant.

2038 GMT (3:38 p.m. EST)

Once the liquid oxygen tank reaches the 95 percent full level, the "rapid load" valve will be closed and the slower "fine load" phase will continue to fill the tank.

2028 GMT (3:28 p.m. EST)

The bottom of the Boeing Delta 2 rocket is icing over as the super-cold liquid oxygen flows into the first stage. LOX loading has passed the 10-minute mark. No problems have been reported.

2023 GMT (3:23 p.m. EST)

Now five minutes into this approximate 25-minute process to fill the first stage liquid oxygen tank.

2018 GMT (3:18 p.m. EST)

Super-cold liquid oxygen, chilled to Minus-298 degrees F, is being pumped into the first stage of the Boeing Delta 2 rocket as the countdown continues for today's 4:54 p.m. EST launch attempt. The liquid oxygen is flowing from a storage tank at pad 17A, through plumbing and into the bottom of the rocket. The LOX and the RP-1 kerosene fuel loaded aboard the vehicle in the last half-hour will be consumed by the first stage main engine.

2014 GMT (3:14 p.m. EST)

The "go" has been given to the launch team to begin preparations for loading the rocket's first stage liquid oxygen tank.

2002 GMT (3:02 p.m. EST)

The first stage fuel tank of the Boeing Delta 2 rocket has been fully loaded for today's planned 4:54 p.m. EST liftoff from Cape Canaveral Air Force Station in Florida. The tank was filled with a highly refined kerosene, called RP-1, during a 20-minute, 3-second process that concluded at 3:02:43 p.m. EST.

The next major task in the countdown will be loading super-cold cryogenic liquid oxygen into the first stage.

Meanwhile, the launch team works the Delta rocket's RIFCA guidance computer has been turned on for flight today.

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

The launch team has computed that the full load for the first stage fuel tank is 9,920 gallons. Over 8,000 gallons are already aboard.

Once the tank is filled with 9,720 gallons, or 98 percent, the "rapid load" valve will be closed and the slower "fine load" phase will continue top off the tank.

1954 GMT (2:54 p.m. EST)

Now two hours from launch. RP-1 loading continues with no problems reported thus far.

The propellant will be guzzled along with liquid oxygen -- to be pumped into the rocket a little later -- by the first stage Rocketdyne RS-27A main engine and twin vernier steering thrusters during the initial four-and-a-half minutes of flight.

1952 GMT (2:52 p.m. EST)

Launch Weather Office Joel Tumbiolo has just provided a briefing to officials. Meteorologists are tracking the ground level winds as well as upper level wind conditions.

The ground winds were out of limits earlier today, but they have eased in the past hour to be below the 23-knot threshold required for liftoff. "Nothing indicates it will all of the sudden increase," Tumbiolo said of the downward trend in wind speed.

Winds aloft are maxing out at 140 knots between 30,000 and 40,000 feet. A series of weather balloons are being released to measure the wind speed and direction -- the information needed by engineers to ensure the Delta 2 rocket had safely fly through such conditions. The balloons will be dispatched periodically until the final portion of the countdown.

1946 GMT (2:46 p.m. EST)

Now four minutes into this approximate 20-minute process to load the rocket's first stage with about 10,000 gallons of refined kerosene fuel. Just over 2,000 gallons have been loaded to this point.

1942 GMT (2:42 p.m. EST)

Fueling of the Delta 2 rocket's first stage has started for today's launch. About 10,000 gallons of a highly refined kerosene propellant, called RP-1, are being pumped into the base of the rocket from a storage tank at pad 17A.

1938 GMT (2:38 p.m. EST)

The Boeing launch team is now beginning the steps to prepare for loading the Delta 2 rocket's first stage RP-1 fuel tank. After verifying valves, sensors, flow meters and equipment are ready, the highly refined kerosene fuel will start flowing into the vehicle.

1930 GMT (2:30 p.m. EST)

Pressurization activities remain in work at pad 17A. First stage fueling should begin shortly. Although the timeline of countdown milestones is running a bit behind schedule, launch is still scheduled for 4:54 p.m. EST.

1910 GMT (2:10 p.m. EST)

The latest check on the ground winds at the pad indicates the speeds have been trending downward in the past little while. The launch time limit is 23 knots. The winds have been gusting above that earlier today. But the most recent report from the weather team said the winds were currently within acceptable range.

1905 GMT (2:05 p.m. EST)

The Complex 17A area is now verified cleared of workers. A warning horn will be sounded three times at the seaside complex as a precaution to alert any remaining personnel in the vicinity that they should leave immediately.

The pad clear status will allow the start of hazardous operations such as the pressurization of helium and nitrogen storage tanks inside the rocket's first and second stages, along with the second stage fuel and oxidizer tanks.

1859 GMT (1:59 p.m. EST)

With the Terminal Count now underway, the launch team will be turning on and configuring the Delta's onboard guidance computer -- called the Redundant Inertial Flight Control Assembly or RIFCA.

1854 GMT (1:54 p.m. EST)

T-minus 150 minutes and counting. The Terminal Countdown has begun for today's launch of the Boeing Delta 2 rocket and the U.S. Air Force's Global Positioning System 2R-9 spacecraft. Over the next three hours, the launch team will prep the rocket, payload and ground support systems for the planned 4:54 p.m. EST (2154 GMT) liftoff from pad 17A at Cape Canaveral Air Force Station in Florida.

1848 GMT (1:48 p.m. EST)

The launch team has been polled for a "go" to resume the countdown as scheduled at the end of this hold. There are 11 people still at the launch pad and a glitch is being addressed with a backup air conditioning system. Although the countdown will continue, some activities cannot occur until the pad area is cleared. There is time in the count to make up for any delays to ensure an on-time liftoff today.

1754 GMT (12:54 p.m. EST)

T-minus 150 minutes and holding. Clocks enter a planned 60-minute built-in hold at this point in the countdown for today's 4:54 p.m. EST liftoff of Delta 2 from Cape Canaveral.

Holds are added to the countdown to give workers a chance to catch up on any activities that may be running behind.

Over the next hour, the entire launch team and management will be seated at their consoles. A series of polls will be conducted to verify all is in readiness for entering Terminal Count at end of the built-in hold.

It is a beautiful day along Florida's Space Coast with not a cloud in the sky. But the winds are gusty and being monitored closely by the launch weather team. Overall, weather officer Joel Tumbiolo says there is a 20 percent chance the winds will violate the 23-knot limit at liftoff time.

1630 GMT (11:30 a.m. EST)

Activities underway at Cape Canaveral are leading up to the start of Terminal Count at 1:54 p.m. EST today. That three-hour sequence will see the Delta 2 rocket fully fueled, the guidance system turned on, final system checks performed and all the other normal work to ready the vehicle for flight.

The loading of RP-1 kerosene fuel into the rocket's first stage is expected to start around 2:15 p.m. Liquid oxygen tanking will follow around 3:10 p.m. The second stage was loaded with storable propellant last week and the third stage is solid-fueled.

Today's launch window extends from 4:54 to 5:09 p.m. EST (2154-2209 GMT).

1430 GMT (9:30 a.m. EST)

Crews have rolled back the mobile service tower enclosing the rocket, setting the stage for final chores to configure the vehicle and secure the launch complex. Launch is scheduled for 4:54 p.m. EST at the opening of today's 15-minute window.

The metal cocoon-like structure is used to assemble the Delta 2 on the seaside pad, as well as provide workers access to all reaches on the vehicle and weather protection for the rocket.

Watch this page for live updates throughout the day!

1400 GMT (9:00 a.m. EST)

Launch of the Boeing Delta 2 rocket and NAVSTAR GPS 2R-9 navigation satellite for the U.S. Air Force is less than 8 hours away. Liftoff remains targeted for 4:54 p.m. EST from Cape Canaveral.

Weather officer Joel Tumbiolo has issued his latest forecast for today's launch opportunity. See the forecast here.

At launch pad 17A, preparations are continuing in advance of retracting the mobile service tower from around the Delta rocket.

SUNDAY, MARCH 30, 2003
0200 GMT (9:00 p.m. EST Sat.)

The U.S. Air Force is ready to launch another Global Positioning System satellite.

The GPS 2R-9 craft will replace an older satellite to ensure the navigation constellation remains healthy for American military forces and civilian users around the globe.

Liftoff is scheduled for 4:54 p.m. EST Monday from pad 17A at Cape Canaveral Air Force Station, Florida. The launch window extends 15 minutes to 5:09 p.m. EST, one minute later than previously announced.

"Just two months ago we were here for GPS 2R-8 launch. Today, that spacecraft is operational to help the coalition forces achieve their objectives in Operation Iraqi Freedom," Air Force launch director Lt. Col. Brad Broemmel told reporters at a news conference Saturday.

"Since then, it has been a 60-day sprint to orbit GPS 2R-9 and replace a satellite launched right here from Cape Canaveral in 1989."

GPS 2R-9 will be boosted into Plane D, Slot 3 of the orbiting fleet. It is expected to enter service in a couple of weeks, joining 27 other GPS satellites currently functioning.

"We look forward to a successful launch and 2R-9's operational availability," Broemmel said. "The team worked hard to make this processing flow as smooth as possible. Right now, we have no issues to report. The Delta 2 rocket, the spacecraft and the Eastern Range are 'go' for launch."

The weather forecast for Monday is generally favorable with an 80 percent chance of meeting the launch rules. The only concern is gusty winds after a cold front moves through the Central Florida region on Sunday.

"The main issue with this system will be the winds behind the front," Launch Weather Officer Joel Tumbiolo said.

"We will be monitoring the wind speeds throughout the day on Monday as they could impact rolling the tower back and vehicle exposure constraints. I do not expect any cloud, rain or thunderstorm issues on Monday.

"The launch constraint during the window is 23 knots. My forecast is 15 gusting to 20 knots. So we will be watching that very closely."

Tumbiolo explained that the 23-knot limit is only in effect during the final minutes of the countdown. Clocks enter a planned hold at T-minus 4 minutes to give the launch team the opportunity to verify all systems are ready for liftoff. Once the countdown resumes, Tumbiolo will call a hold if a wind gust is detected that violates the allowable limit.

The count would recycle back to T-minus 4 minutes. If there is enough time remaining in the day's launch window, another attempt could occur.

Should the launch be postponed for any reason, the forecast for Tuesday and Wednesday looks good, Tumbiolo said.

"If we were to go into a 24- or 48-hour delay, the winds decrease and the cloud conditions remain favorable."

SATURDAY, MARCH 29, 2003
2130 GMT (4:30 p.m. EST)

The final series of launch readiness reviews were successfully completed today, clearing the way for Monday's liftoff of the Boeing Delta 2 rocket and GPS 2R-9 spacecraft from Cape Canaveral, Florida.

The launch window originally announced by Boeing has been tweaked slightly. The window now extends for 15 minutes -- from 4:54 to 5:09 p.m. EST.

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

Today's updated weather forecast has been posted here.

FRIDAY, MARCH 28, 2003

Today's updated weather forecast has been posted here.

THURSDAY, MARCH 27, 2003

Today's updated weather forecast has been posted here. The chance of acceptable weather has fallen from 90 to 80 percent from yesterday's early forecast.

WEDNESDAY, MARCH 26, 2003

With war raging half-a-world away, a routine but crucial rocket launch from Florida next week will deploy a fresh tactical navigation satellite into the U.S. military's Global Positioning System -- the orbiting network that ground, air and sea forces rely upon for guidance.

A Boeing Delta 2 rocket is scheduled for blastoff at 4:54 p.m. EST (2154 GMT) Monday from Cape Canaveral's pad 17A. The day's available launch window extends 14 minutes.

Read our launch preview story.

Watch this page for live coverage of the countdown and launch!