BY JUSTIN RAY

Follow the countdown and launch of the Lockheed Martin Atlas 2A rocket with NASA's Tracking and Data Relay Satellite-I. Reload this page for the very latest on the mission.

FRIDAY, MARCH 8, 2002

An advanced communications satellite built to keep NASA's orbiting data relay network working for years to come was successfully hauled into space Friday aboard a Lockheed Martin Atlas 2A rocket. Read our full launch story.

Here are several video clips of the Atlas mission with TDRS-I for our Spaceflight Now Plus subscribers. You are not a yet a subscriber, click here to sign up for a low monthly or annual fee.

Video coverage for subscribers only:
   VIDEO: 2 1/2-MINUTE MOVIE OF THE LAUNCH QT or RV
   VIDEO: REMARKABLE SCENES OF ROCKET STAGING QT or RV
   VIDEO: REPLAY OF VIEW FROM CAPE INDUSTRIAL AREA QT or RV
   VIDEO: VIEW OF UMBILICALS PULLING AWAY AT LIFTOFF QT or RV
   VIDEO: POWERFUL TRACKING CAMERA FOLLOWS ROCKET QT or RV
   VIDEO: PICTURESQUE CAMERA ANGLE OF LIFTOFF QT or RV
   VIDEO: CAPE PRESS SITE VIEW OF THE LAUNCH QT or RV
   VIDEO: MOBILE TOWER ROLLED AWAY FROM ROCKET QT or RV
   VIDEO: THURSDAY'S PRELAUNCH NEWS CONFERENCE QT or RV
   VIDEO: ATLAS 2A PRE-LAUNCH PREPARATIONS QT or RV
   VIDEO: TDRS-I PRE-LAUNCH PREPARATIONS QT or RV
   VIDEO: NASA PROJECT MANAGER SPEAKS ON TDRS QT or RV
   VIDEO: BOEING MANAGER SPEAKS ON TDRS QT or RV

2358 GMT (6:58 p.m. EST)

NASA reports controllers acquired the signal from TDRS-I through a ground station at Diego Garcia in the Indian Ocean at 6:34 p.m. EST, which was much earlier than the anticipated first contact via Canberra, Australia. At this point, the space agency says all looks good.

2328 GMT (6:28 p.m. EST)

T+plus 29 minutes, 40 seconds. SPACECRAFT SEPARATION! NASA's Tracking and Data Relay Satellite-I, or TDRS-I, has been released into space following launch by the Lockheed Martin Atlas 2A rocket. All appears to have gone well during the launch. This marks the 60th consecutive successful launch by an Atlas rocket dating back to 1993.

First contact with the TDRS-I satellite is scheduled to occur through the Canberra tracking station in Australia in about 25 minutes. This pass with allow controllers a chance to verify the health of the spacecraft.

We'll pause our coverage at this point. Check back later for an update on the satellite's status and a full wrap-up story on the launch.

We'll also have a ton of video clips to present to our Spaceflight Now Plus subscribers of this absolutely beautiful launch!

2327 GMT (6:27 p.m. EST)

T+plus 28 minutes, 30 seconds. Spinup of the Centaur upper stage has started in advance of payload deployment in about one minutes. Data from the rocket is still being relayed to the ground via an orbiting NASA Tracking and Data Relay Satellite.

2326 GMT (6:26 p.m. EST)

T+plus 27 minutes. Depletion of liquid oyxgen triggered the Centaur MECO 2. This flight used the Minimum Residual Shutdown feature that allows the Centaur to fire until it runs out of fuel, giving the payload as high of an orbit as possible. Quick look info indicates the high point of the orbit 2,000 nautical miles higher than targeted.

2325 GMT (6:25 p.m. EST)

T+plus 26 minutes, 30 seconds. The Centaur is beginning its reorientation maneuver to prepare for releasing TDRS-I.

2324 GMT (6:24 p.m. EST)

T+plus 25 minutes, 55 seconds. MECO 2. Centaur has completed its second firing, completing the powered phase of today's launch. Good shut down of the twin RL-10 engines reported. Coming up on deployment of the TDRS-I satellite at about T+plus 29 minutes, 37 seconds.

2324 GMT (6:24 p.m. EST)

T+plus 25 minutes, 15 seconds. Engine firing continues. Systems reported normal.

2323 GMT (6:23 p.m. EST)

T+plus 24 minutes, 35 seconds. Centaur is up and burning again at full thrust. The two RL-10 engines have reignited for an 80-second firing to accelerate the TDRS-I payload into its required orbit around Earth.

2321 GMT (6:21 p.m. EST)

T+plus 22 minutes. The vehicle is now approaching the African Ivory Coast as it coasts above the Central Atlantic. Now about two minutes until Centaur engine restart.

2319 GMT (6:19 p.m. EST)

T+plus 20 minutes. NASA Launch Manager Omar Baez says the Atlas booster stage was a little low on performance, but within the allowable margin. The Centaur upper stage made up the performance during its first firing just as it was supposed to.

2315 GMT (6:15 p.m. EST)

T+plus 16 minutes. Data indicates the vehicle remains in good shape in this coast period in preparation for restart of the Centaur upper stage, which is about 8 minutes away.

2313 GMT (6:13 p.m. EST)

T+plus 14 minutes. NASA's orbiting Tracking and Data Relay Satellite System, which this launch will bolster with the delivery of the more capable TDRS-I satellite, is currently relaying telemetry from the Centaur upper stage back to engineers at the Cape.

2311 GMT (6:11 p.m. EST)

T+plus 12 minutes. Lockheed Martin reports the parking orbit achieved is down to the decimal point with a high point of 312 nautical miles and low point of 90.3 miles.

2308 GMT (6:08 p.m. EST)

T+plus 9 minutes, 54 seconds. MECO 1. The Centaur main engines have shut down as planned following the first of two planned firings to deliver the TDRS-I payload into a preliminary parking orbit. The vehicle will coast for about 14 minutes before the Centaur reignites.

2308 GMT (6:08 p.m. EST)

T+plus 9 minutes. Downrange distance 844 miles, velocity 14,000 mph.

2307 GMT (6:07 p.m. EST)

T+plus 8 minutes. Just under two minutes left in this first burn of the Centaur upper stage.

2306 GMT (6:06 p.m. EST)

T+plus 7 minutes. Vehicle still flying on the proper track. Altitude 103 miles, downrange distance 466 miles, velocity 10,000 mph.

2304 GMT (6:04 p.m. EST)

T+plus 5 minutes, 45 seconds. Centaur engines continue to burn normally. Altitude 96 miles, speed 8,800 miles per hour.

2304 GMT (6:04 p.m. EST)

T+plus 5 minutes. Ignition of Centaur's two engines has been confirmed. Full thrust reported for the Centaur's RL-10 powerplants.

2303 GMT (6:03 p.m. EST)

T+plus 4 minutes, 40 seconds. The sustainer engine on Atlas has shut down as planned. Separation of the Atlas stage confirmed.

2303 GMT (6:03 p.m. EST)

T+plus 4 minutes. Vehicle continues right down the predicted Range track.

2302 GMT (6:02 p.m. EST)

T+plus 3 minutes, 45 seconds. The payload fairing has been jettisoned. It is no longer needed to protect TDRS-I satellite during flight through the atmosphere.

2302 GMT (6:02 p.m. EST)

T+plus 3 minutes. The booster engines have shut down and the booster package -- the bottom section of the rocket -- has been jettisoned. The sustainer engine of the Atlas vehicle still firing.

2301 GMT (6:01 p.m. EST)

T+plus 2 minute, 30 seconds. Vehicle reported right on the proper Range ground track.

2300 GMT (6:00 p.m. EST)

T+plus 1 minute, 40 seconds. Altitude 8 miles, downrange distance 4 miles, velocity 1,200 miles per hour

2300 GMT (6:00 p.m. EST)

T+plus 62 seconds. Atlas is now flying through the area of maximum dynamic pressure.

2259 GMT (5:59 p.m. EST)

T+plus 30 seconds. Pitch program is in as the vehicle heads eastward away from Florida.

2259 GMT (5:59 p.m. EST)

T+plus 15 seconds. Vehicle has cleared the tower and all looks good.

2259 GMT (5:59 p.m. EST)

LIFTOFF! Liftoff of the Lockheed Martin Atlas rocket launching the TDRS-I spacecraft -- NASA's newest communications relay station in the sky.

2258 GMT (5:58 p.m. EST)

T-minus 31 seconds. Launch Sequence Start. The Atlas 2A rocket's onboard computer is now controlling the remainder of the countdown.

In the next few seconds the liquid hydrogen and liquid oxygen vent valves will be locked and the flight data recorders will be readied. The engine ignition sequence will begin at T-minus 2.4 seconds.

2258 GMT (5:58 p.m. EST)

T-minus 1 minute. Engines are being verified ready for flight. The final status checks of the propellant and pneumatic systems are upcoming to confirm the Atlas and Centaur stages are "go" for launch.

In the past minute, the inertial navigation unit was launch enabled, liquid hydrogen tanking was secured, fuel tank pressures reported stable and the ignition enable switch was closed.

2257 GMT (5:57 p.m. EST)

T-minus 2 minutes. Pressurization of the Atlas/Centaur vehicle has started. Tanks now being brought to proper pressure levels for flight. Also, the vehicle's inadvertent separation destruct safety system has been armed.

Shortly, the Centaur upper stage will go to internal power and the flight termination system will be armed.

2256 GMT (5:56 p.m. EST)

T-minus 3 minutes. The water system is being readied for activation at launch pad 36A. Water will flood the pad to suppress the sound produced at liftoff and protect the ground support systems.

And the TDRS-I satellite is confirmed on internal power and ready for launch today.

2255 GMT (5:55 p.m. EST)

T-minus 4 minutes. The Atlas booster stage and Flight Termination System are switching from ground-supplied power to internal batteries for launch.

2254 GMT (5:54 p.m. EST)

T-minus 5 minutes and counting! The clocks are running again. Now in the final portion of today's countdown for the launch of the Lockheed Martin Atlas 2A rocket with NASA's Tracking and Data Relay Satellite-I, TDRS-I, spacecraft from pad 36A at Cape Canaveral Air Force Station in Florida. Liftoff remains set to occur on time at 5:59 p.m. EST.

2253 GMT (5:53 p.m. EST)

The TDRS-I spacecraft atop the Atlas 2A rocket has switched to internal power for launch.

2253 GMT (5:53 p.m. EST)

Standing by to resume the countdown in one minute for blastoff at 5:59 p.m. EST.

Should a problem force the countdown to be stopped inside the final 5 minutes, here is an explanation of recycle options depending on when the clocks were halted:

From the start of the automatic countdown at T-minus 31 seconds until T-minus 0.7 seconds, the launch conductor will be able to stop the countdown manually. A hold during the automatic sequence between T-minus 31 seconds and T-minus 11.3 seconds will equire a recycle to T-minus 5 minutes. A hold between T-minus 12 seconds and T-minus 9 seconds will require a recycle to T-minus 5 minutes for a minimum of one hour to re-initialize the INU in preparation for reentering the terminal count. A hold after Atlas start tanks are pressurized or Centaur equipment module vent door squibs fire (T-minus 8.65 seconds) and before T-minus 4 seconds will necessitate a launch abort and require a recycle to T-minus 24 hours. A hold after T-minus 4 seconds but prior to T-minus 0.7 seconds will necessitate a launch abort and require a 48 hour recycle.

2252 GMT (5:52 p.m. EST)

Lockheed Martin Launch Director Adrian Laffitte has given his "go" to resume the countdown and proceed to liftoff at 5:59 p.m. EST. There are now no technical problems being addressed, the weather is within limits, upper level winds are acceptable and the Range is clear. Standing by to resume the countdown in two minutes.

2252 GMT (5:52 p.m. EST)

The Lockheed Martin final readiness poll of the entire launch team was just performed by Launch Conductor Ed Christiansen in the Complex 36 Blockhouse. Everyone reported "go" for launch!

2250 GMT (5:50 p.m. EST)

Flight control has just declared it is now "go" for launch. The line items have been disabled and the team is ready to proceed.

2249 GMT (5:49 p.m. EST)

Now 10 minutes away from the new target launch time. Two line items in the red-line monitor program are being disabled in order to proceed with the countdown today.

2244 GMT (5:44 p.m. EST)

Once the flight control engineers of the launch team complete their assessment of the red-line monitor program, the "go" will be given to transfer the TDRS-I spacecraft to internal power for liftoff.

2239 GMT (5:39 p.m. EST)

NEW LAUNCH TIME. The flight control team reports the red-line monitor program has been reset. But the team needs to go through the red-line file and check it item by item. So the launch time has been pushed back another 10 minutes to 5:59 p.m. EST.

2238 GMT (5:38 p.m. EST)

NASA Launch Manager Omar Baez has completed a final pre-launch poll of his team. No problems were reported. "NASA is ready for launch."

2236 GMT (5:36 p.m. EST)

Initial reports from the launch team indicate the computer program reset and system checks look OK.

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

NEW LAUNCH TIME. The flight control team reports it will need another 10 minutes to check through its setup following the computer reset. So the countdown will hold here at T-minus 5 minutes an additional 10 minutes, pushing liftoff to 5:49 p.m. EST.

2229 GMT (5:29 p.m. EST)

Now 10 minutes away from the scheduled launch time. The launch team continues to work the technical problem experienced a few minutes ago. The red-line monitor program will have to be restarted as a result.

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

The flight control system team reported a momentary loss of its land-line signal. They will have to restart the red-line monitor system that watches to ensure systems do no fall out of preset limits. It isn't known yet if this can be accomplished in time to support liftoff at 5:39 p.m. EST. Today's available launch window extends to 6:19 p.m. EST if needed.

2222 GMT (5:22 p.m. EST)

Today's launch will mark the 22nd flight of an Atlas 2A rocket, the least powerful version of the Atlas family of vehicles the is currently in service. One more Atlas 2A is left to fly -- the TDRS-J launch scheduled for November. All previous 21 Atlas 2As have flown successfully since debuting in June 1992.

The Atlas program as a whole is going for its 60th consecutive successful launch today, a string that began in 1993.

2219 GMT (5:19 p.m. EST)

T-minus 5 minutes and holding. The countdown has entered this final planned hold. The pause is scheduled to last 15 minutes. Countdown activities continue right on time. Weather is fine, Atlas 2A rocket is fueled with the liquid oxygen and liquid hydrogen tanks all at flight level, and the TDRS-I spacecraft remains in good shape. Liftoff is targeted for 5:39 p.m. EST.

The launch team just reported a few glitches on the ground. Not clear if any will cause a delay.

2214 GMT (5:14 p.m. EST)

T-minus 10 minutes and counting. Coming up on the planned 15-minute built-in hold at T-minus 5 minutes. Countdown is still progressing smoothly with no problems being addressed by the launch team.

2207 GMT (5:07 p.m. EST)

Launch Weather Officer Jim Sardonia just reported that all conditions are near-ideal for liftoff today. There are no weather concerns for launch.

2204 GMT (5:04 p.m. EST)

T-minus 20 minutes and counting. Countdown clocks are ticking down to the T-minus 5 minute mark where a 15-minute hold will occur. Liftoff still set for 5:39 p.m. EST (2239 GMT).

The Flight Termination System self test has been completed successfully. A little while ago, interrogation checks were performed to verify the rocket's C-band beacon is ready for use to track the vehicle during flight.

2157 GMT (4:57 p.m. EST)

The liquid oxygen tank inside the Atlas first stage is now at flight level, completing the operation to fuel the rocket. However, the Atlas and Centaur tanks will have to be topped off as the countdown continues to replenished the cryogenics that naturally boil away.

2154 GMT (4:54 p.m. EST)

Topping of the Atlas liquid oxygen tank is underway. The Centaur liquid hydrogen is now reported at flight level.

2152 GMT (4:52 p.m. EST)

The Centaur liquid hydrogen tank has reached 97 percent level.

Also, an inhibited self test of the rocket's Flight Termination System is starting. The FTS would be used to destroy the vehicle in the event of a malfunction during launch.

2148 GMT (4:48 p.m. EST)

The Atlas liquid oxygen tank has reached the 98 percent level where it is being maintained. Topping to 100 percent will be completed shortly.

All continues to go well in the countdown for today's $220 million launch of the Lockheed Martin Atlas 2A rocket and NASA's TDRS-I data relay satellite at 5:39 p.m. EST. There is a 40-minute launch window available if needed.

2144 GMT (4:44 p.m. EST)

The Centaur hydrogen tank is now at 80 percent. The Atlas liquid oxygen tank is at 90 percent.

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

Now one hour away from the scheduled launch time. There are no problems to report with the rocket, payload or weather.

Loading of the rocket with super-cold rocket fuel is continuing as planned. The Centaur hydrogen tank is now 50 percent full; the Atlas liquid oxygen tank is at 70 percent; and the Centaur liquid oxygen tank has been filled.

2130 GMT (4:30 p.m. EST)

The liquid hydrogen chilldown is now complete and the super-cold fuel is flowing to fill the Centaur upper stage. The cryogenic propellant will be consumed with liquid oxygen by the stage's Pratt & Whitney-made RL-10 engines to propel the TDRS-I satellite into the targeted geosynchronous transfer orbit this afternoon.

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

The Atlas liquid oxygen tank is now at the 30 percent level as the countdown continues on schedule for launch at 5:39 p.m. EST today from Cape Canaveral Air Force Station in Florida.

2123 GMT (4:23 p.m. EST)

At launch pad 36A, the Atlas stage liquid oxygen tank is now being filled. The rocket's shiny exterior has turned a frosty white as a thin layer of ice forms from the super-cold liquid oxygen.

Also, the final alignment of the Atlas rocket's inertial navigation guidance computer has been completed, and the flight control system final preps are now beginning.

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

Centaur liquid oxygen topping to flight level is underway. As the countdown proceeds, the tank will be replenished to replace the cryogenic liquid oxygen that naturally boils away.

Meanwhile, loading of liquid oxygen into the Atlas booster stage will be getting underway in earnest momentarily.

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

The Centaur liquid oxygen tank has reached 95 percent full level where it is being maintained. Topping to 100 percent will be completed shortly.

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

Launch is now 90 minutes away. Fueling is continuing, with the Centaur liquid oxygen tank now at 70 percent. There are no significant technical problems with the Atlas 2A rocket or TDRS-I spacecraft that are standing in the way of launch at 5:39 p.m. EST.

The chilldown conditioning of liquid hydrogen propellant lines at pad 36A is now starting. This process is like the one performed on the liquid oxygen side whereby a small amount of the liquid is released from the pad's storage tank to prepare the plumbing for transferring the Minus-423 degree F fuel into the rocket.

Also at this time the door of the Complex 36 Blockhouse is being sealed, protecting the 120-member launch team. The Blockhouse is located a few hundred feet away from the Atlas 2A rocket at pad 36A, and serves as the control center for the countdown to launch.

2106 GMT (4:06 p.m. EST)

Th liquid oxygen tank inside the Centaur upper stage is now half-full.

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

The Centaur upper stage's liquid oxygen tank is now 20 percent full in this early portion of fueling operations.

2053 GMT (3:53 p.m. EST)

Chilldown conditioning of the liquid oxygen transfer lines at pad 36A has been completed and the launch team is now beginning to fill the Centaur upper stage with its its supply of super-cold cryogenic oxidizer. The liquid oxygen is chilled to Minus-298 degrees F, and will be consumed by the Centaur's twin RL-10 engines along with liquid hydrogen to be pumped into the stage a little later in the countdown.

2040 GMT (3:40 p.m. EST)

The "chilldown" procedure is starting to thermally condition the liquid oxygen propellants lines at pad 36A in advance of loading the Centaur upper stage. Chilldown is a process in which a small amount of the super-cold liquid oxygen is released from the pad's storage tank into the feed lines that lead to the rocket.

Meanwhile, gaseous helium chilldown of the Centaur engines and pneumatic bottle charge for the stage have started.

2039 GMT (3:39 p.m. EST)

T-minus 105 minutes and counting. The countdown is running again following the 30-minute planned built-in hold. There are no technical problems being reported by the launch team and the weather remains excellent this afternoon. All systems are now "go" to begin fueling the Atlas/Centaur rocket starting in the next few minutes.

The countdown will continue to T-minus 5 minutes where a planned 15-minute built-in hold is scheduled. Launch of the Atlas 2A rocket is targeted for 5:39 p.m. EST.

2035 GMT (3:35 p.m. EST)

Lockheed Martin Launch Conductor Ed Christiansen has just polled the launch team for a readiness check in preparation to begin fueling the Atlas rocket once the countdown resumes. No problems were reported. The technicians at the pad said the complex securing work was now complete and Christiansen instructed them to clear the area. A few minutes ago NASA Launch Manager Omar Baez polled his team with no issues announced then either.

2024 GMT (3:24 p.m. EST)

Now half-way through this 30-minute scheduled hold at T-minus 105 minutes.

2009 GMT (3:09 p.m. EST)

T-minus 105 minutes and holding. Clocks have entered a planned 30-minute hold period for the countdown to the launch of TDRS-I aboard the Lockheed Martin Atlas 2A rocket.

The count has 45 minutes of built-in holds scheduled over the course the day that will lead to liftoff at 5:39 p.m. EST (2239 GMT). A second and final hold is planned at T-minus 5 minutes for 15 minutes. The holds are designed to give the launch team a window of time to work any problems that could arise without delaying other pre-flight preparations.

The mobile service tower has been retracted to the launch position and final checks of the pad are underway before workers clear the area in preparation for fueling. Also, the launch team is performing the final alignment of the vehicle's guidance computer following the recent completion of a navigation test.

The Air Force has announced there are no COLAs, or Collision Avoidance periods, that will prohibit liftoff during any portion of today's 40-minute launch window.

1941 GMT (2:41 p.m. EST)

The 219-foot tall mobile service tower at pad 36A has begun to roll away from the Atlas 2A rocket. The structure is being wheeled back to expose the rocket for launch, which is just under three hours away.

The tower is used to erect the rocket on the launch pad, provide access for workers to all areas of the vehicle and give protection from the weather. It is electrically driven on four-wheel assemblies.

The countdown remains on schedule and the weather is virtually perfect here at Cape Canaveral this afternoon for launch.

1924 GMT (2:24 p.m. EST)

T-minus 150 minutes and counting. "Man stations for Integrated Launch Operations." That is the call to the launch team for members to take their positions at Cape Canaveral Air Force Station as the countdown enters the final hours hours and 15 minutes to this afternoon's liftoff of the Lockheed Martin Atlas 2A rocket carrying NASA's TDRS-I tracking and data relay spacecraft.

There are two built-in holds, lasting for a total of 45 minutes, scheduled into the countdown at T-minus 105 minutes and T-minus 5 minutes.

Liftoff remains set for 5:39 p.m. EST.

The countdown is being controlled from the Complex 36 Blockhouse where the 120-member launch team has assembled to oversee the activities leading up to liftoff of this Atlas 2A rocket, designated AC-143.

At launch pad 36A, access platforms and equipment inside the mobile service tower have been stowed, and technicians are preparing for retraction of the structure from around the rocket in about 15 minutes.

1909 GMT (2:09 p.m. EST)

The Lockheed Martin launch team is preparing to start the Integrated Launch Operations in 15 minutes. Launch remains scheduled for 5:39 p.m. EST.

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

The countdown is underway at Cape Canaveral Air Force Station in Florida for today's launch of the Lockheed Martin Atlas 2A rocket carrying NASA's Tracking and Data Relay Satellite-I. The mission is valued at approximately $220 million.

Officials weren't reporting any problems this morning as clocks started ticking down to the planned 5:39 p.m. EST blastoff from pad 36A.

It is a very pleasant morning here on the Space Coast with warm temperatures, a light wind and just a few clouds. Launch Weather Officer Jim Sardonia says conditions should be favorable for liftoff time. His latest forecast calls for less than a 10 percent chance a coastal rainshower could delay the launch.

"Ideal weather conditions are expected for launch today as strong high pressure aloft has brought dry and stable air into the local area. At launch time, skies will be clear to partly cloudy and winds at the surface will be easterly and light. These favorable weather conditions are expected to remain in the area on Saturday and Sunday in the event of a 24 or 48-hour delay.

"The only slight concern for launch day will be the chance of an isolated coastal rainshower developing over the waters east of the launch pad and moving back towards Cape Canaveral."

The launch time conditions are predicted to include a few cumulus clouds at 3,000 feet with 1/8th sky coverage and tops at 5,000 feet, visibility of 7 miles or greater, easterly winds from 070 degrees at 8 gusting to 15 knots, a temperature of 70 to 72 degrees F and relative humidity of 75 percent.

We will begin our live coverage of the count and 30-minute flight of the Atlas/Centaur rocket at 2:24 p.m. when the Integrated Launch Operations phase of the countdown begins.

THURSDAY, MARCH 7, 2002

Launch of NASA's Tracking and Data Relay Satellite-I, or TDRS-I, remains on scheduled for 5:39 p.m. EST (2239 GMT) on Friday aboard the next-to-last Atlas 2A rocket built by Lockheed Martin.

The weather forecast is unchanged with a 90 percent chance of meeting the launch weather rules.

The countdown is scheduled to begin at 8:49 a.m. EST at Cape Canaveral's Launch Complex 36. Throughout the day the crews in the blockhouse and at pad 36A will proceed through their standard countdown chores needed to ready the Atlas booster and its Centaur upper stage for launch, as well as the ground systems and TDRS-I spacecraft.

Highlights of activities planned, in the order they are scheduled to be performed, include Centaur propulsion launch preps, powering up the rocket's flight control system, Atlas propulsion and hydraulic systems preps, preps of the pad's tower and mobile service structure, performing the flight control operational test, the internal power test of Atlas/Centaur, performing a navigation test of rocket's guidance computer, Centaur engine igniter checks, starting Centaur helium purges and starting liquid hydrogen and liquid oxygen system final preps.

The Integrated Launch Operations -- the final portion of the countdown in which all members of the launch team participate -- will start at 2:24 p.m. EST. Retraction of the mobile service tower from around the rocket is slated for 2:39 p.m. EST.

Countdown clocks will enter a planned 30-minute hold at the T-minus 105 minute mark starting at 3:09 p.m. EST. During this time the launch team will have a chance to catch up on any work that might be running behind schedule.

Fueling operations will commence at 3:53 p.m. EST with super-cold liquid oxygen flowing into the Centaur upper stage. Loading of liquid oxygen into the Atlas booster stage should start at 4:19 p.m. EST. The final segment of fueling will begin at 4:33 p.m. EST when liquid hydrogen is pumped into the Centaur. The Atlas stage was fueled with its supply of RP-1 kerosene on Monday.

A final planned hold is scheduled at T-minus 5 minutes for 15 minutes in duration. If there are no problems standing in the way of liftoff, the countdown will resume at 5:34 p.m. EST for an on-time launch.

Watch this page for complete live coverage of Friday's countdown and launch!

For our Spaceflight Now Plus subscribers here are some movies previewing this launch:

Video coverage for subscribers only:
   VIDEO: ATLAS 2A PRE-LAUNCH PREPARATIONS QT or RV
   VIDEO: TDRS-I PRE-LAUNCH PREPARATIONS QT or RV
   VIDEO: NASA PROJECT MANAGER SPEAKS ON TDRS QT or RV
   VIDEO: BOEING MANAGER SPEAKS ON TDRS QT or RV

WEDNESDAY, MARCH 6, 2002

A new spacecraft to replenish NASA's preeminent tracking and data relay satellite constellation is scheduled for launch Friday aboard a Lockheed Martin Atlas 2A rocket from Cape Canaveral.

Liftoff is targeted to occur at 5:39 p.m. EST (2239 GMT) from pad 36A. The day's available launch window extends 40 minutes to 6:19 p.m. EST.

Mission managers will hold the Launch Readiness Review on Thursday at Kennedy Space Center to give final approval to proceed with the countdown to liftoff.

"Everything is on schedule and we're not tracking any issues," NASA spokesman George Diller said today.

Air Force Launch Weather Officer Jim Sardonia says there is a 90 percent chance of acceptable conditions for liftoff. The slight chance of coastal rainshowers is the only concern.

"Easterly winds are expected to remain along the coast for the remainder of the week. Computer models suggest an increase in the chance of coastal rainshowers on Thursday and Friday (morning). These rainshowers are expected to decrease during the launch countdown on Friday. Favorable conditions are expected during the launch window on Friday and Saturday. A weak frontal system is expected to move into the local area on Sunday in the event of a 48-hr delay. The only concern for launch day will be the chance of isolated coastal rainshowers moving over the coast of Cape Canaveral."

The launch time conditions are predicted to include scattered cumulus clouds at 5,000 feet with 3/8ths sky coverage and tops at 8,000 feet, visibility of 7 miles, easterly winds from 100 degrees at 10 gusting to 18 knots and a temperature of 70 to 72 degrees F.

The Atlas rocket and its Centaur upper stage will boost the 7,031-pound TDRS-I satellite into a highly elliptical subsynchronous transfer orbit following a 29-minute, 37-second flight. The target orbit at spacecraft deployment has a high point of 16,578 nautical miles, low point of 120 nautical miles and inclination of 27 degrees. However, the Centaur will be allowed to fire until it runs out of propellant, which could result in a higher orbit.

The satellite will later fire its onboard engine to raise and circularize the altitude to geostationary orbit at 22,300 miles and reduce inclination.

The TDRS system is NASA's primary means of relaying television, data and science information from space shuttles, the International Space Station, Hubble Space Telescope and a host of other robotic space missions.

The TDRS-I satellite is the second of three next-generation craft built by Boeing for NASA to keep the orbiting network functioning for years to come. The new craft offer increased bandwidth and greater tuning flexibility than the previous TRW-built series.

"Once in place, the three next-generation TDRS satellites will double the capacity of data transmission and will provide nearly continuous communications links between Earth and space for the space shuttle, the International Space Station and with dozens of unmanned scientific satellites in low-earth orbit," said Jack Wormington, senior vice president of programs for Boeing Satellite Systems.

NASA is spending about $840 million on the TDRS-H, I and J effort, including the three satellites, three rockets for the launches and necessary modifications to a ground control station in White Sands Complex.

The space agency currently operates a constellation of seven TDRS satellites. The first six were launched aboard space shuttles from 1983 through 1995; the newest was hauled aloft by an Atlas rocket in June 2000. TDRS-J is scheduled for launch in November aboard another Atlas 2A. One other satellite, TDRS-B, was lost in the 1986 Challenger accident.