BY JUSTIN RAY

Follow the countdown and launch of the Boeing Delta 2 rocket with NASA's Space Infrared Telescope Facility. Reload this page for the very latest on the mission.

SUNDAY, AUGUST 24, 2003
2225 GMT (6:25 p.m. EDT)

The Boeing Delta 2-Heavy rocket stands ready for tonight's countdown and launch of NASA's $1.2 billion Space Infrared Telescope Facility mission.

The mobile service tower has been retracted from the rocket over the past few minutes. Workers will spend the next couple of hours getting the tower secured into position and performing the other various chores to ready the pad for launch. Special sound suppression equipment at pad 17B -- large exhaust ducts that tunnel away from the pad -- cannot be set up until after tower rollback since the structure's base blocks the pathways.

Officials are not reporting any significant problems and the weather forecast still looks favorable with an 80 percent chance of good conditions.

The Terminal Countdown is slated to start at 10:35 p.m. EDT (0235 GMT). The loading of RP-1 kerosene fuel into the rocket's first stage will begin a short time later, followed by first stage liquid oxygen tanking. There is just an instant in time that the rocket can be launched tonight -- 1:35:39 a.m. EDT (0535:39 GMT) -- or else the mission will have to wait 48 hours.

Earlier this afternoon, the cryogenic helium servicing of the Space Infrared Telescope Facility spacecraft was completed with the unhooking of the ground umbilicals. Should the liftoff be scrubbed at any point after the umbilical disconnection, another launch attempt cannot occur for 48 hours while the spacecraft is reserviced. So the next try would come no sooner than 2:03:09 a.m. EDT Wednesday.

2150 GMT (5:50 p.m. EDT)

The cocoon-like mobile service tower enclosing the Boeing Delta 2 rocket at launch pad 17B is now driving away from the vehicle. This is a major event in the sequence leading to tonight's blastoff. The one-second launch opportunity is 1:35:39 a.m. EDT (0535:39 GMT).

The tower structure is used to assemble the rocket's various stages and boosters on the seaside pad. It also provides protection from the weather.

Some last-minute work on the rocket delayed the tower rollback a short time.

2107 GMT (5:07 p.m. EDT)

The retraction of the mobile service tower is being delayed while technicians complete some last-minute work on the Delta 2 rocket. The structure is now expected to begin its roll to the launch position at 6:30 p.m. EDT (2230 GMT).

2042 GMT (4:42 p.m. EDT)

Good day from Cape Canaveral's Complex 17. A group of reporters and photographers have gathered to watch the rollback of the mobile service tower from around the Boeing Delta 2 rocket. Crews are working to move the tower into the launch position at pad 17B for tonight's planned liftoff of the SIRTF space telescope for NASA.

1720 GMT (1:20 p.m. EDT)

Preparations continue for tonight's launch of the Boeing Delta 2 rocket carrying NASA's Space Infrared Telescope Facility from Cape Canaveral, Florida. Workers will retract the mobile service tower from around the rocket late this afternoon. The Terminal Countdown begins at 10:35 p.m. at the Launch Minus 3-hour point.

Launch Weather Officer Joel Tumbiolo has issued his latest forecast, which you can read here.

SATURDAY, AUGUST 23, 2003
2155 GMT (5:55 p.m. EDT)

The last-minute review of electronics boxes used by the Delta 2 rocket has been completed. The result: NASA and Boeing have given a "go" for Monday's predawn launch of the Space Infrared Telescope Facility.

Two separate engineering teams reached the same conclusion that -- although the two power and control boxes on the Delta 2 cannot be inspected at the launch pad -- the screening process for the units is highly reliable. That gave managers the confidence that the boxes on the rocket do not have loose capacitors like a similar unit in the factory, NASA spokesman George Diller said.

Pre-launch preparations continue for starting the countdown Sunday afternoon. Liftoff will occur at 1:35:39 a.m. EDT from pad 17B at Cape Canaveral Air Force Station, Florida.

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

The latest launch weather forecast is available here.

Mission officials will be meeting today to discuss the results of the power and control electronics box review. NASA is expected to announce the decision -- whether or not to proceed with launch on Monday morning -- sometime late this afternoon or early evening. We will update this page when news becomes available.

FRIDAY, AUGUST 22, 2003

The Launch Readiness Review was conducted this morning at Kennedy Space Center. There is one technical issue being addressed by engineers -- a paperwork review to ensure two electronics boxes on the Delta 2 rocket's first and second stages are fit to fly.

A similar box in testing was found to have loose capacitors inside, prompting officials to ensure the units aboard the Delta 2 on the launch pad are free of concern. The review of records from boxes on the rocket will verify that they were produced at a different time and passed their checkout.

NASA Launch Manager Omar Baez said he was optimistic the issue would be put to rest on Saturday.

Otherwise, the launch vehicle and SIRTF spacecraft are ready to fly.

The weather forecast for Monday launch attempt is still favorable. See the forecast here.

THURSDAY, AUGUST 21, 2003

The fourth and final of NASA's Great Observatories is set for launch Monday from Cape Canaveral. A tracking ship is expected to reach its required position in the Indian Ocean to support the 1:35 a.m. EDT liftoff.

"It will be a photo finish," NASA spokesman George Diller said today. "But we are pressing on for a Monday launch."

Technicians at pad 17B began cryogenic liquid helium servicing of the SIRTF spacecraft today as planned.

The Launch Readiness Review is scheduled for Friday morning to give approval to start the countdown.

The weather forecast for Monday's predawn launch opportunity is favorable. See the forecast here.

Watch this page for comprehensive live coverage throughout the countdown and flight of the Delta 2 rocket. Our updates will begin Sunday afternoon with rollback of the mobile service tower from around the rocket.

TUESDAY, AUGUST 19, 2003

Launch of NASA's Space Infrared Telescope Facility aboard Boeing's Delta 2-Heavy rocket is being delayed at least two days -- to early Monday morning -- because a tracking ship needed to support the mission in the Indian Ocean is being held up by bad weather. Read our full story.

FRIDAY, APRIL 18, 2003

Worried that a suspect rocket nozzle on one of the Boeing Delta 2's solid-fueled boosters could trigger a catastrophic failure during launch, NASA on Friday grounded the Space Infrared Telescope Facility until mid-August. Read our full story.

MONDAY, APRIL 14, 2003

NASA has targeted Sunday, April 27 as the new launch date for the Space Infrared Telescope Facility atop the inaugural Boeing Delta 2 Heavy rocket. The $1.2 billion mission was scheduled to fly April 18 from Cape Canaveral only to be postponed by senior agency officials to resolve concerns with the Delta 2. Read our full story.

THURSDAY, APRIL 10, 2003

The launch of NASA's final "Great Observatory" -- the Space Infrared Telescope Facility -- is being delayed due to concerns associated with the Boeing Delta 2 rocket that will send $1.2 billion mission into space, sources said on Thursday. Read our full story.

SUNDAY, MARCH 9, 2003

NASA's Space Infrared Telescope Facility arrived in Florida last week to begin a month-long period of final preparations before being attached to its Delta 2 booster for launch in mid-April. Read our full story.