BY JUSTIN RAY

Follow the countdown and launch of a U.S. Air Force Titan 4B rocket with the Milstar 2-F2 communications satellite. Reload this page for the very latest on the mission. We also have a text only version of this page.

MONDAY, FEBRUARY 26, 2001
2100 GMT (4:00 p.m. EST)

The U.S. Air Force said today all systems are "go" for Tuesday's launch of the Titan 4 rocket from Cape Canaveral Air Force Station. Weather forecasters are calling for favorable conditions.

The earlier technical problem with the rocket, which Air Force press releases said was a telemetry system glitch, actually involved the vehicle's automatic safety destruct system, Col. Mike Dunn, the mission director, told reporters at a news conference today. The problem was traced to suspect equipment and fixed over the weekend.

There are no other problems being reported at present, and preparations are on schedule to start the countdown at 12:27 a.m. EST (0527 GMT) Tuesday. Liftoff remains set to occur at 1:57 p.m. EST (1857 GMT) at the opening of a four-hour window.

SATURDAY, FEBRUARY 24, 2001
2350 GMT (6:50 p.m. EST)

GO FOR LAUNCH. The Titan 4B rocket has been cleared for liftoff Tuesday with the Milstar communications satellite cargo, the Air Force announced today after isolating and correcting a problem with the vehicle's first stage telemetry relay system.

The launch window for Tuesday's attempt will be 1:57 to 5:57 p.m. EST (1857-2257 GMT).

Meteorologists are now calling for an 80 percent chance of meeting the launch weather rules. The concerns are precipitation and layered clouds. Air Force Launch Weather Officer Johnny Weems issued this update earlier today:

"Stationary front in area today will produce gusty east-southeast wind and occasional showers this morning, gradually diminishing by tonight as front dissipates. Another front will approach the Florida peninsula on Sunday; then pass through the local area late Monday. Flow aloft (west-southwest to east-northeast) over the southeastern U.S. will prevent these weakening fronts from totally moving off the Florida peninsula. Frequent disturbances developing in the southwestern U.S. will continue to move from the west to east with most of the cooler air and energy associated with these fronts remaining north of the local area; thus greatest threat of showers remain north of the Florida peninsula. Guidance suggests greater threat of showers and cloudiness during latter part of week."

The conditions on Tuesday are predicted to include clouds at 3,000 feet with 2-to-3/8ths sky coverage, some mid-level clouds at 10,000 feet with 1-to-2/8ths sky coverage and another deck at 28,000 feet with 1-to-2/8ths sky coverage, seven miles visibility, northeasterly winds from 060 degrees at 11 gusting to 15 knots, temperature of 74 degrees F, relative humidity of 68 percent and a slight chance of showers in the area.

Should the launch be delayed, the forecast for Wednesday and Thursday calls for a 70 percent chance of acceptable conditions both days with the same concerns of precipitation and layered clouds.

FRIDAY, FEBRUARY 23, 2001
2348 GMT (6:48 p.m. EST)

DELAYED FURTHER. Officials have decided to slip the Titan 4B rocket launch of the Milstar 2-F2 military communications satellite to Tuesday at the earliest. The extra time is needed so technicians can further study and fix a problem with the rocket's airborne telemetry system on the first stage, which relays to the ground information on the vehicle's performance during flight.

Tuesday's four-hour launch window extends from 1:57 to 5:57 p.m. EST (1857-2257 GMT). Forecasters give a 70 percent chance of acceptable weather conditions.

The concern with a telemetry system was found Thursday night during routine pre-launch processing at Cape Canaveral Air Force Station's Complex 40. An electrical voltage drop was detected in the system, alerting crews of a problem. The situation is still being analyzed, the Air Force said late today.

"This is a very important mission," launch director Lt. Col. David Jones said in a statement tonight. "We can't afford to take unnecessary risks and launch this critical Milstar satellite before we are confident in our entire launch system."

2020 GMT (3:20 p.m. EST)

Senior launch officials have scheduled a telecon for later this evening to review the status of troubleshooting efforts into the telemetry relay system of the Titan 4B rocket's first stage. Managers could establish a new launch date at the meeting if the problem is resolved. For now, the liftoff won't occur before Sunday afternoon at the earliest. We will update this page as soon as further information becomes available.

1945 GMT (2:45 p.m. EST)

Air Force Launch Weather Officer Johnny Weems has put out his updated forecast for Sunday, Monday and Tuesday, should the Titan 4 rocket be scheduled for liftoff on one of those days.

"Cold front in local area today will undergo rapid modification as wind gradually becomes easterly and strengthens. Another front, potentially stronger, will approach the Florida peninsula on Sunday; then pass through the local area late Sunday night. Front will produce significant precipitation through Northern Florida but the chance of widespread shower activity will diminish as it passes through the local area. Main concerns on Sunday will be isolated showers and layered cloudiness. Anvils could become concern if thunderstorms form south over the Gulf of Mexico in advance of the front."

The conditions on Sunday are predicted to include clouds at 3,000 feet with 2-to-3/8ths sky coverage and another deck at 28,000 feet with 1-to-2/8ths sky coverage, seven miles visibility, southeasterly winds from 160 degrees at 14 gusting to 19 knots, temperature of 75 degrees F, relative humidity of 68 percent and a slight chance of showers in the area. Overall there is a 70 percent chance of meeting the launch weather rules with precipitation and layered clouds the concerns.

The forecast for Monday calls for an 80 percent chance of being able to launch with the concerns being the possibility of rain above 3,500 feet in the sky and layered clouds. Tuesday is also 80 percent "go" due to precip above 3,500 feet.

1615 GMT (11:15 a.m. EST)

Concerns about the $455 million Titan 4B rocket's airborne telemetry system has forced Saturday's launch attempt to be called off. Technicians discovered "anomalous electrical readings" from the system during testing Thursday night at Cape Canaveral's Complex 40 launch pad, the Air Force says.

"When the Titan 4B booster is on the launch stand, this link is tested by sending telemetry data via this link. During the testing, there was an electrical voltage drop in this specific component, which is located on the first stage of the Titan 4B rocket. The launch team doesn't know what caused this voltage drop and is troubleshooting the issue," an Air Force statement said this morning.

"Telemetry data provides critical launch vehicle performance information to the launch team while the vehicle is in flight."

The Air Force has reserved Sunday and Monday launch opportunities on the Eastern Range pending resolution of the problem. Sunday's four-hour launch window opens at 2:05 p.m. EST, and Monday's four minutes earlier.

The Lockheed Martin-built rocket will loft the $750 million Milstar 2-F2 military communications satellite. The craft is destined to be launched into geostationary orbit 22,300 miles above the equator inclined 4.5-degrees. The Air Force says the satellite's orbital slot will be 90 degrees West longitude with a coverage zone of North and South America. The satellite is designed to relay secure, jam-resistant communications to U.S. military forces.

More information of launch rescheduling is expected later this afternoon.

1420 GMT (9:20 a.m. EST)

DELAY. Tomorrow's planned launch of a Titan 4B rocket has been postponed due to a vehicle issue. Further details on the problem and when the launch might be rescheduled are expected later today. Stay tuned!

0501 GMT (12:01 a.m. EST)

Pre-flight preparations continue at Cape Canaveral where the Air Force and Lockheed Martin launch team is getting postured to start the countdown later today for Saturday's blastoff of a Titan 4B rocket. The weather forecast remains favorable with a 90 percent chance of acceptable conditions.

We'll have a full mission preview following the pre-launch news conference scheduled for this afternoon.

And don't forget our live Webcast of the launch, which will start at 12:30 p.m. EST (1730 GMT) Saturday.

THURSDAY, FEBRUARY 22, 2001

After an extended wait on the launch pad to ensure its guidance computer brain was free of defects, an Air Force Titan 4B rocket is finally cleared for blastoff this weekend with the fourth Milstar military communications satellite.

After several weeks of testing and analysis to understand a problem with an Inertial Measurement Unit computer back in the factory, the computer aboard the Lockheed Martin-built Titan 4B has been given a clean bill of health.

Liftoff from Complex 40 at Cape Canaveral Air Force Station in Florida is scheduled for Saturday at 2:09 p.m. EST (1909 GMT), the opening of a four-hour launch window.

The launch will take nearly seven hours to complete with the Military Strategic and Tactical Relay 2-F2 communications satellite arriving in geostationary orbit 22,300 miles above the planet.

The rocket's two-stage core vehicle was loaded with its storable fuels earlier this week -- nitrogen tetroxide oxidizer and Aerozine 50 propellant made of hydrazine and unsymetrical dimethyl hydrazine.

The Centaur upper stage will be fueled with super-cold liquid oxygen and liquid hydrogen during the final hours of the countdown Saturday.

Weather forecasters are calling for generally favorable conditions for the liftoff with just a 10 percent chance of violating the launch rules. The concerns are gusty ground winds and precipitation above 3,500 feet that the rocket could fly through during flight.

Air Force Launch Weather Officer Johnny Weems issued this summary on Wednesday:

"Weak cold front approaching area on Thursday will cause increasing cloudiness and slight chance of showers on Friday as it passes through local area. Small change in temperatures as winds rapidly shift back to an easterly direction. Surface high pressure will dominate area on Saturday with east winds gradually becoming more southeasterly and strengthening through the afternoon. Main concerns on Saturday will be 54 and 162 feet wind with a slight chance of light rain, mainly aloft. Conditions gradually worsen Sunday through Monday as another front approaches area."

The conditions on Saturday are predicted to include clouds at 3,000 feet with 2-to-3/8ths sky coverage and another deck at 28,000 feet with 1-to-2/8ths sky coverage, seven miles visibility, southeasterly winds from 130 degrees at 12 gusting to 18 knots, temperature of 74 degrees F, relative humidity of 68 percent and a slight chance of showers in the area.

The forecast for Sunday and Monday calls for rain and layered clouds concerns both days with a 70 percent chance of meeting the launch weather rules.

Spaceflight Now will provide comprehensive coverage of this launch with continuous live reports during the countdown and flight. We'll also offer a live streaming video Webcast of the launch.

Check back on Friday for a complete launch preview package!