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.

WEDNESDAY, FEBRUARY 28, 2001

A sophisticated military communications switchboard-in-the-sky that promises to revolutionize the amount of information available to U.S. soldiers on the battlefield was successfully placed into Earth orbit Tuesday in a picture-perfect Titan 4 rocket launch. Read our full story.

0421 GMT (11:21 p.m. EST Tues.)

SUCCESS DECLARED! The $800 million Milstar communications satellite has been delivered into orbit successfully today by the $455 million Titan 4B-Centaur rocket, the U.S. Air Force has announced. The satellite's power-generating solar arrays are now being deployed.

The Centaur did perform its final firing about 40 minutes ago to circularize Milstar's orbit to geostationary altitude.

We will have a final wrap-up story on today's launch momentarily.

0346 GMT (10:46 p.m. EST Tues.)

T+plus 6 hours, 26 minutes. The third and final burn by Centaur should be completed. Deployment of Milstar is scheduled for 9 minutes from now. Confirmation of this final phase of powered flight for today's launch and successful spacecraft separation will come from the Air Force in one announcement shortly. We'll post the information here as soon as it becomes available.

TUESDAY, FEBRUARY 27, 2001
2235 GMT (5:35 p.m. EST)

T+plus 75 minutes. We will again pause our coverage. Check back for further updates following the third Centaur burn and spacecraft separation later tonight.

2232 GMT (5:32 p.m. EST)

T+plus 72 minutes. The Centaur is now entering another coast period -- this one lasting until T+plus 6 hours, 22 minutes when the third burn is scheduled. That firing will last about two minutes to circularize the orbit.

The current altitude is 168 nautical miles. The orbit achieved from this second Centaur burn is 19,410 by 112 nautical miles.

2231 GMT (5:31 p.m. EST)

T+plus 71 minutes, 45 seconds. Centaur has completed its second burn to boost Milstar 2-F2. Main engine cut off No. 2, or MECO 2, has been confirmed.

2230 GMT (5:30 p.m. EST)

T+plus 70 minutes. About one minute remaining in the Centaur MES 2 burn.

2228 GMT (5:28 p.m. EST)

T+plus 68 minutes. This upper stage firing will raise one side of the Milstar orbit from the low-altitude parking orbit to geosynchronous orbit. The third burn scheduled more than five hours from now will circular the orbit at 22,300 miles above the planet's equator.

2227 GMT (5:27 p.m. EST)

T+plus 67 minutes. Vehicle performing normally as the second Centaur burn continues. This firing will last five minutes in duration.

2226 GMT (5:26 p.m. EST)

T+plus 66 minutes, 35 seconds. The twin-engine Centaur has reignited for the second of three burns today that are designed to place the 10,000 pound Milstar satellite into geostationary orbit 22,300 miles high. The engine start time was revised by about a minute of pre-flight predictions.

2223 GMT (5:23 p.m. EST)

T+plus 63 minutes. Pitch, yaw and roll rates of the Centaur stage reported normal. Altitude currently 106 miles.

2221 GMT (5:21 p.m. EST)

T+plus 61 minutes. Officials report today's flight continues to go extremely well. The Centaur and Milstar stack are currently flying above Australia. The upper stage is orienting itself in preparation for the upcoming engine firing, now four minutes away.

2159 GMT (4:59 p.m. EST)

T+plus 39 minutes. We have posted a QuickTime movie clip of today's liftoff.

2139 GMT (4:39 p.m. EST)

T+plus 19 minutes. The Centaur and Milstar continue their quiet coast around Earth at altitude of 111.45 miles. Officials report the launch has gone successfully to this point. But the flight won't be completed until Milstar is deployed into geostationary orbit some 6 hours and 35 minutes after liftoff.

We will pause our coverage at this point. Check back for confirmation of the upcoming Centaur second burn in about an hour. Also watch for some pictures and movie clips from today's beautiful launch of the Titan 4 rocket.

2132 GMT (4:32 p.m. EST)

T+plus 12 minutes. The Centaur upper stage and attached Milstar payload are now in a coast period. This will continue until T+plus 65 minutes, 2 seconds when the Centaur engines reignite for a scheduled five-minute burn to begin the journey to geosynchronous orbit.

2131 GMT (4:31 p.m. EST)

T+plus 11 minutes, 40 seconds. MECO 1. The Centaur engines have shut down as planned following the first of three firings needed to deliver the Milstar satellite into the proper geostationary orbit today.

2131 GMT (4:31 p.m. EST)

T+plus 11 minutes. About 30 seconds to go in this first Centaur burn. Both Centaur engines performing normally, officials report.

2129 GMT (4:29 p.m. EST)

T+plus 9 minutes, 50 seconds. The Titan 4 rocket's second stage has shut down. The spent stage has separated from the Centaur upper stage. And now confirmation of Centaur main engine ignition. The upper stage is now firing to achieve a low-altitude parking orbit around Earth.

2128 GMT (4:28 p.m. EST)

T+plus 8 minutes, 30 seconds. Second stage engine shutdown systems enabled.

2128 GMT (4:28 p.m. EST)

T+plus 8 minutes. About a minute left in the second stage burn.

2127 GMT (4:27 p.m. EST)

T+plus 7 minutes. The second stage continued to perform as expected, pushing the Milstar spacecraft to orbit. The engine produces just over 100,000 pounds of thrust.

2126 GMT (4:26 p.m. EST)

T+plus 6 minutes. Altitude 87 miles, downrange distance 334 miles, velocity 16,700 mph.

2125 GMT (4:25 p.m. EST)

T+plus 5 minutes, 30 seconds. First stage engines have completed their job and the spent stage has dropped away to fall into the Atlantic Ocean. The second stage liquid-fueled engine has now ignited.

2125 GMT (4:25 p.m. EST)

T+plus 5 minutes. First stage engine shutdown systems enabled. Coming up on engine cutoff in 25 seconds.

2124 GMT (4:24 p.m. EST)

T+plus 4 minutes. The Air Force confirms separation of the 76-foot long payload fairing enclosing the Milstar spacecraft atop the Titan 4B rocket. First stage continues to fire. Altitude of 62 miles, downrange distance 138 miles.

2122 GMT (4:22 p.m. EST)

T+plus 2 minutes, 45 seconds. The twin solid rocket boosters have burned out and separated as planned. The vehicle is currently at an altitude of 38 miles, downrange distance 54 miles.

2122 GMT (4:22 p.m. EST)

T+plus 2 minutes, 20 seconds. First stage main engine start. Both liquid-fueled engines up and burning. The engines produce about 550,000 pounds of thrust.

2121 GMT (4:21 p.m. EST)

T+plus 90 seconds. A good burn of the solid rocket boosters still reported. The will fire for another minute.

2121 GMT (4:21 p.m. EST)

T+plus 60 seconds. A smooth flight reported so far.

2120 GMT (4:20 p.m. EST)

T+plus 30 seconds. Both solid rocket motors burning normally to propel the Titan 4 rocket into a clear Florida afternoon sky.

2120 GMT (4:20 p.m. EST)

T+plus 15 seconds. Vehicle has cleared the tower. Pitch and roll programs are in.

2120 GMT (4:20 p.m. EST)

LIFTOFF! Liftoff of the Air Force Titan 4B rocket with Milstar 4 -- a secure military communications switchboard in the sky.

2119 GMT (4:19 p.m. EST)

T-minus 1 minute. Centaur going inertial.

2118 GMT (4:18 p.m. EST)

T-minus 90 seconds.

2118 GMT (4:18 p.m. EST)

T-minus 2 minutes.

2117 GMT (4:17 p.m. EST)

T-minus 2 minutes, 30 seconds. The Range recorders are running.

2117 GMT (4:17 p.m. EST)

T-minus 3 minutes. At liftoff, the Titan 4B will be powered by the two solid rocket motors, each producing 1.7 million pounds of thrust. Once the launch tower is cleared, the vehicle will perform a roll maneuver for positioning on the 93 degree flight azimuth for this launch. Titan will head eastward away from Cape Canaveral, ultimately sending its Milstar 2-F2 satellite payload toward a geosynchronous orbit.

2115 GMT (4:15 p.m. EST)

T-minus 4 minutes, 30 seconds and counting. The countdown sequence is being controlled by the PAGE -- Programmable Aerospace Ground Equipment system.

2115 GMT (4:15 p.m. EST)

T-minus 5 minutes and counting. The countdown is once again underway at Cape Canaveral for today's launch of the Ttian 4B rocket. Liftoff is slated to occur at 4:20 p.m. EST. All systems reported go!

2114 GMT (4:14 p.m. EST)

The launch team is preparing to pick up the countdown in one minute. The Titan 4 rocket is now six minutes away from liftoff on its 31st flight.

2112 GMT (4:12 p.m. EST)

The Air Force-controlled Eastern Range has given its final clear to launch.

2110 GMT (4:10 p.m. EST)

Five minutes left in this scheduled hold. Now 10 minutes away from launch.

2109 GMT (4:09 p.m. EST)

The Air Force Launch Conductor has polled the launch team with no problems reported.

2105 GMT (4:05 p.m. EST)

T-minus 5 minutes and holding. Countdown clocks have now stopped for this planned 10 minute built-in hold. During this period, final readiness checks will be performed by the launch team to ensure all systems are go for flight today.

For now, all appears ready for liftoff of the Titan 4 rocket at 4:20 p.m. EST (2120 GMT) today from Complex 40 at Cape Canaveral Air Force Station in Florida.

2102 GMT (4:02 p.m. EST)

A Collision Avoidance period, or COLA, has been announced that will prohibit liftoff during an 8-minute period starting at 4:29 p.m. EST. This cutout ensures the rocket does not launch on a course that would take it too close to the international space station.

2100 GMT (4:00 p.m. EST)

T-minus 10 minutes and counting. Clocks will be pausing at T-minus 5 minutes for the planned 10-minute built-in hold. No problems are currently being reported.

2055 GMT (3:55 p.m. EST)

T-minus 15 minutes and counting. The final "go" for flight vehicle and spacecraft readiness today will be made by the Mission Director. The final operational "go" including safety and launch range assets is made by the Air Force Space Command Ops Group Commander. The final launch decision authority resides with the Space Wing Commander and is based on the inputs from the Mission Director and the Ops Group Commander.

2050 GMT (3:50 p.m. EST)

Now a half-hour away from the planned liftoff time. At this time, controllers are scheduled to power on the Milstar 2-F2 military communications satellite nestled in the nose cone atop the Titan 4B rocket.

The Range is now "go" for launch at 4:20 p.m. EST. A waiver was issued to clear the earlier communications link problem with the Antigua downrange tracking station.

2032 GMT (3:32 p.m. EST)

Range Safety is now beginning final checks of the command destruct receivers that would be used to destroy the Titan rocket should it veer off course or experience a problem during launch today.

2030 GMT (3:30 p.m. EST)

The 19-story Titan 4B rocket is fully fueled for its Earth-shaking liftoff, which is now 50 minutes away. The vehicle weighs about 2,074,000 pounds at present with the Milstar satellite cargo atop the massive launcher. The Titan is comprised of a two-stage core vehicle, two solid rocket boosters, a Centaur upper stage and 76-foot payload fairing.

Read the fact sheet for a description of the rocket -- the most powerful in America's unmanned fleet.

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

Now one hour away from launch. The Range remains down due to a problem with land line communications link between the Cape and Antigua tracking station. The Air Force remains hopeful the issue will be resolved soon. Today's launch window extends to 5:57 p.m. EST (2257 GMT).

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

Range Safety says the computer modeling of the toxic cloud and blast dangers for today's launch -- based upon weather conditions and other factors -- shows acceptable conditions for liftoff. These models are run to determine if the launch area workers or the public would be threatened in the event the Titan 4 rocket explodes during flight.

2015 GMT (3:15 p.m. EST)

A weather briefing by Air Force Launch Weather Officer Johnny Weems has just been completed with a favorable report. There remains less than a 10 percent chance of weather conditions violating the launch rules. The only area being watched is a band of clouds and associated showers about 35 or 40 miles off the coast of Cape Canaveral.

The launch time forecast is calling for the chance of some scattered clouds at 3,000 and 28,000 feet, 7 miles visibility, northeasterly winds 7 to 10 knots and a temperature of 74 degrees F.

All the weather criteria is currently "go" for launch and expected to remain that way.

The upper level winds are also acceptable with peak winds of 65 to 67 knots at 38,000 feet.

2000 GMT (3:00 p.m. EST)

The loading of the Centaur upper stage with liquid hydrogen rocket fuel -- chilled to Minus-423 degrees F -- is nearing completion. The hydrogen tank is now 95 percent full. Also at this time, the launch team is pressurizing the Titan rocket's second stage oxidixer tank.

1950 GMT (2:50 p.m. EST)

Now 90 minutes away from the appointed liftoff time of the Titan 4 B-41 rocket nicknamed "Gus" in honor of the fallen astronaut Virgil "Gus" Grissom.

Today's launch will mark the 31st for a Titan 4 rocket dating back to 1989 and the ninth flight of the newer Titan 4B model. It will be the 13th mission of a liquid-fueled Centaur upper stage on a Titan 4. And this is the 21st Titan 4 to launch from Cape Canaveral, the 11th from Complex 40.

1931 GMT (2:31 p.m. EST)

Loading of the Centaur upper stage with liquid oxygen -- chilled to Minus-298 degrees F -- has been completed. And pressure checks are reported acceptable. The Cenatur will now be fueled with cryogenic liquid hydrogen as the countdown continues.

1920 GMT (2:20 p.m. EST)

T-minus 110 minutes and counting. Now two hours away from today's new launch time. With one built-in hold scheduled into the countdown -- a 10 minute hold at T-minus 5 minutes -- launch is expected at 4:20 p.m. EST (2120 GMT). Today's available launch window extends to 5:57 p.m. EST (2257 GMT).

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

The computer-controlled process of fueling the Centaur upper stage is underway at Cape Canaveral's Complex 40. Super-cold liquid oxygen is currently being pumped into stage. Liquid hydrogen tanking will commence once oxygen loading is completed.

The Range remains red due to a communications link problem between the Cape and Antigua tracking station. That issue is being worked and officials believe the problem will be resolve before today's 4:20 p.m. EST launch time.

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

NEW LAUNCH TIME! The Air Force has formally announced the new liftoff time for the Titan 4 rocket today is 4:20 p.m. EST (2120 GMT), a delay of two hours and 23 minutes. Officials report there were a variety of minor ground support equipment problems this morning that delayed the countdown.

At this point, the count is ticking once more after being stopped earlier and tasks to the ready the rocket for liftoff are again underway.

The weather remains nearly perfect for launch. There is less than a 10 percent chance of conditions not meeting the launch weather rules today. The skies are mostly clear, there is a light southeast wind at 10 knots and warm temperatures. A nice Florida day.

1845 GMT (1:45 p.m. EST)

The Range has just announced it is "no go" due to a problem with land-line transmissions with the Antigua tracking station downrange from Cape Canaveral. It is a commercial carrier problem and BellSouth and WorldCom have begun troubleshooting the issue.

1830 GMT (1:30 p.m. EST)

Good day and welcome to our live continuous coverage of the Titan 4B rocket launching the fourth Milstar communications satellite. After an earlier delay in the countdown caused by some equipment troubles, the launch team is getting back on track for liftoff this afternoon at around 4:15 p.m. EST (2115 GMT). The exact launch time has still not been announced by the Air Force, however.

At this time engineers are preparing to begin the chilldown procedure to thermally condition the fuel lines at the pad in advance of loading super-cold liquid oxygen into the Centaur upper stage.

You can listen into the countdown audio in our live Webcast. The video portion of the broadcast will start at 2:30 p.m. EST.

1740 GMT (12:40 p.m. EST)

As a result of the hour or so delay in today's scheduled launch, Lockheed Martin commentary will be pushed back too. So our live Webcast will now start around 1:30 p.m. EST.

1645 GMT (11:45 a.m. EST)

The Air Force has now confirmed that the countdown is running about an hour behind schedule, as we reported earlier. The launch will be pushed back as a result. A new liftoff time has not been announced, but is expected to be after 2:30 p.m. EST (1930 GMT). Today's available launch window extends to 5:57 p.m. EST (2257 GMT).

Spokespeople do not yet know what caused this delay. We will pass along any further information as it becomes available.

1555 GMT (10:55 a.m. EST)

Activities continue for this afternoon's launch of the Titan rocket from Cape Canaveral. The weather is absolutely beautiful for liftoff and no major technical issues standing in the way of launch have been reported by the Air Force. There has been some indication preparations are running about an hour behind schedule. What impact, if any, that will have on the 1:57 p.m. EST (1857 GMT) launch time has not yet been announced.

1330 GMT (8:30 a.m. EST)

The mobile service tower has been rolled away from the Titan 4B rocket as pre-launch preparations continue at Cape Canaveral's Complex 40 for today's liftoff.

Like a building on wheels, the tower is known as the largest and heaviest self-propelled structure in the world. It weighs in at 11.2 million pounds. The 260-foot tall metal cocoon shields the Titan rocket while on the seaside launch pad from the weather while providing access to all areas of the vehicle. Its Class 100,000 cleanroom is where the Milstar satellite underwent final processing after being attached to the rocket.

Over the next two hours or so, pad crews will finish chores to lock the tower in its parked position and securing the complex facilities for launch. The loading of the Centaur upper stage with liquid oxygen and liquid hydrogen should get start by around 11:30 a.m. EST.

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

America's principle secure military communications relay network in space should get an $800 million addition today if a crucial rocket launch from Cape Canaveral is successful.

Lockheed Martin's Titan 4B rocket -- the most powerful unmanned booster in the U.S. fleet -- will carry aloft the Military Strategic and Tactical Relay (Milstar) 2-F2 from Complex 40 at Cape Canaveral Air Force Station in Florida.

The available launch window extends from 1:57 to 5:57 p.m. EST (1857-2257 GMT). Air Force weather forecasters are calling for an 80 percent chance of acceptable conditions. The only worries come in the form of rain and layered clouds.

The conditions predicted 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, winds initally from the east at 080 degrees at 10 gusting to 14 knots then becoming southeasterly at 120 degrees by the end of the window, temperature of 74 degrees F, relative humidity of 68 percent and a slight chance of showers in the area.

The $455 million Titan 4 and its liquid-fueled, high-energy Centaur upper stage are supposed to deliver the 10,000-pound Milstar into geostationary orbit 22,300 miles above the equator.

This launch mirrors one that occurred two years ago. But the Air Force and Lockheed Martin hope the end result is far better.

In April 1999, the Milstar 2-F1 satellite was propelled into a worthlessly low orbit because corrupt software aboard the Centaur caused the stage to make erratic firings and veered off the proper course. It was the third consecutive time that a Titan 4-based mission had failed in a period of eight months.

If all goes well today, the Lockheed Martin-built Milstar will be deployed into the correct orbit six hours and 35 minutes after launch. The craft's orbital parking slot is 90 degrees West longitude where it will cover North and South America. Two older Milstars remain in operation with two more scheduled for launches over the next two years.

Like the satellite lost in 1999, this Milstar being launched today is a second generation that carries additional antennas for increased communications capabilities in a package known as the Medium Data Rate payload. They also feature the Low Data Rate system flown on the first two Milstars. The LDR is designed to transmit voice, data and fax information at 75 bits per second (bps) to 2400 bps. The MDR payload will be able to transmit 1.5 Mega bps.

The Milstar constellation acts as a secure, jam-resistant switchboard-in-the-sky for the president and warfighter.

It is this satellite system that would be called upon during war, linking the White House and Pentagon with troops on the battlefield, and relaying the instantaneous communications to launch a nuclear attack.

"In the communications business, they don't come any more important than Milstar," said Brig. Gen. Craig Cooning, the Air Force's program executive officer for space. "I call it the FedEx of communications systems. When it absolutely, positively has to be there, this is the system," Cooning said in a twist of the shipping company's motto.

The countdown is scheduled to get underway at 12:27 a.m. EST (0527 GMT). Launch managers will arrive on station at their consoles a few hours later to oversee retraction of the mammoth mobile service tower from around the Titan 4, which is expected to occur sometime around 9 a.m. EST. (1400 GMT).

Once the Complex 40 pad is secured and area cleared of all workers, the Centaur upper stage will be loaded with super-cold liquid oxygen and liquid hydrogen cryogenic propellant. The two-step operation is slated to start at 11:22 a.m. EST (1622 GMT).

A 10-minute planned hold is built into the countdown at T-minus 5 minutes, giving officials the chance to perform final readiness polls to verify there are no problems standing in the way of liftoff. If no issues are identified, the countdown clock will pick up for an on-time launch at 1:57 p.m. EST (1857 GMT).

We will provide complete live coverage of the countdown and flight on this page throughout the day. You can also tune into our live streaming Webcast starting at about 12:30 p.m. EST (1730 GMT).

Read our earlier status center coverage.