BY JUSTIN RAY

January 21, 2000 -- Read our description of the countdown and launch of a Lockheed Martin Atlas 2A rocket and the U.S. Air Force's DSCS B8 communications satellite. Reload this page for the very latest on the mission.

0600 GMT (1:00 a.m. EST)

The gusty winds that threatened to scuttle tonight's launch cooperated after all and the Lockheed Martin Atlas 2A rocket successfully boosted a U.S. Air Force communications satellite into space. It was the first space launch from planet Earth of 2000 and the new millennium.

Read our launch story for a summary of the countdown and mission. Also be sure to check out our launch photo gallery and movies on the righthand side of this page.

This will conclude our Mission Status Center coverage of AC-138 and the DSCS B8 satellite launch.

0132 GMT (8:32 p.m. EST)

Lockheed Martin has announced the orbital data achieved in tonight's launch. The information indicates a very successful placement of the DSCS B8 into Earth orbit. The apogee is 19,291.721 nautical miles of the expected 19,282.155 nautical miles, a perigee of 122.659 nautical miles of expected 122.578 nautical miles and inclination right on the money at 26.5 degrees.

The DSCS B8 spacecraft will continue in this highly elliptical orbit until its IABS kick motor is fired on Saturday evening. The engine firing will circularize the orbit at geostationary altitude of about 22,300 miles high while decreasing the orbital inclination. On Monday and Tuesday, the satellite's solar arrays will be deployed, the sun and Earth will be acquired for spacecraft pointing and the power system will be actived to recharge onboard batteries. Over the coming two months the satellite will be placed over California coastline for complete on-orbit testing. Controllers will then move DSCS B8 into its operational position at 175 degrees East, beginning its service life in mid-May.

Check back later tonight for video and images of the countdown and launch.

0129 GMT (8:29 p.m. EST)

SPACECRAFT SEPARATION. The U.S. Air Force's Defense Satellite Communications Satellite B8 spacecraft has separated from the Centaur upper stage following tonight's successful launch of the Lockheed Martin Atlas 2A rocket. The launch of AC-138 marks the 47th consecutive success for Atlas rockets dating back to 1993.

0128 GMT (8:28 p.m. EST)

T+plus 25 minutes, 30 seconds. The Centaur is spinning up to 4.7 rpm for release of DSCS B8.

0127 GMT (8:27 p.m. EST)

T+plus 24 minutes, 30 seconds. The Centaur is now turning to the proper position for spacecraft separation.

0127 GMT (8:27 p.m. EST)

T+plus 24 minutes. Main engine cutoff confirmed. The Centaur engines have shut down as planned.

0126 GMT (8:26 p.m. EST)

T+plus 23 minutes. The Centaur firing continues with no problems reported. Cutoff will come in about 45 seconds.

0125 GMT (8:25 p.m. EST)

T+plus 22 minutes, 30 seconds. Centaur has reignited and both RL-10 engines reported nominal.

0124 GMT (8:24 p.m. EST)

T+plus 21 minutes, 30 seconds. The Ascension Island tracking station has acquired signal from the rocket. Propellant tank pressurizations are confirmed. Centaur ignition in less than one minute.

0123 GMT (8:23 p.m. EST)

T+plus 20 minutes. So far so good in this first Atlas launch of 2000. This launch will be over in about six minutes when DSCS B8 is released into orbit.

0120 GMT (8:20 p.m. EST)

T+plus 17 minutes, 30 seconds. Shortly the Ascension Island tracking station will acquire the rocket. The station will relay data on the Centaur's second burn and spacecraft separation.

0119 GMT (8:19 p.m. EST)

T+plus 16 minutes. There is really nothing to report at this point in the flight. The Centaur upper stage and spacecraft are in a quiet coast period over the Central Atlantic Ocean approaching the African coast. Centaur restart is six minutes away.

0115 GMT (8:15 p.m. EST)

T+plus 12 minutes. Lockheed Martin reports the Centaur burn was about three seconds longer than planned, but that is not a problem. The parking orbit achieved has an apogee altitude of 485.262 nautical miles for an expected 485.15 nmi. The perigee is 79.945 nmi of the planned 80.0.

Reignition of the Centaur for its second of two burns to place DSCS B8 into transfer orbit will occur at T+plus 22 minutes, 17 seconds.

0113 GMT (8:13 p.m. EST)

T+plus 10 minutes, 15 seconds. Confirmation now that the two Centaur engines have shut down as plnned. Centaur, with DSCS B8 attached, is in an elliptical parking orbit. The duo will now quietly coast now for the next 12 minutes.

0112 GMT (8:12 p.m. EST)

T+plus 9 minutes, 30 seconds. Coming up on shutdown of the Centaur upper stage in just over 30 seconds. Velocity is over 14,000 mph.

0111 GMT (8:11 p.m. EST)

T+plus 8 minutes, 30 seconds. The Antigua Island tracking station has acquired the rocket as it speeds southeast away from Cape Canaveral.

0111 GMT (8:11 p.m. EST)

T+plus 8 minutes. Now about two minutes left in the first Centaur burn. Downrange distance is 650 miles and velocity is 11,788 mph.

0110 GMT (8:10 p.m. EST)

T+plus 7 minutes. The rocket's speed has increased to 10,700 mph since lifting off just seven minutes ago.

0109 GMT (8:09 p.m. EST)

T+plus 6 minutes. Centaur engines burning well. Altitude is 90 miles, downrange distance 370 miles and velocity of 9,100 mph.

0108 GMT (8:08 p.m. EST)

T+plus 5 minutes, 10 seconds. Centaur ignition confirmed. Centaur now in the longer of its two scheduled firings.

0107 GMT (8:07 p.m. EST)

T+plus 4 minutes, 50 seconds. The sustainer engine has cut off and Atlas stage separation.

0107 GMT (8:07 p.m. EST)

T+plus 4 minutes. The payload fairing has been jettisoned.

0106 GMT (8:06 p.m. EST)

T+plus 3 minutes, 30 seconds. Altitude is 42 miles, downrange distance 82 miles and velocity is 6,300 mph.

0106 GMT (8:06 p.m. EST)

T+plus 3 minutes. The booster package has been jettisoned from the Atlas stage. No problems reported so far in the flight. Sustainer engine of the vehicle still burning as expected.

0105 GMT (8:05 p.m. EST)

T+plus 2 minutes. Atlas engines continue to perform well. No problems reported. Velocity up to 3,000 mph.

0104 GMT (8:04 p.m. EST)

T+plus 1 minute. Altitude is two miles, downrange distance .7 miles and velocity over 500 mph.

0103 GMT (8:03 p.m. EST)

T+plus 30 seconds. Roll maneuver completed to position the vehicle on the proper trajectory.

0103 GMT (8:03 p.m. EST)

LIFTOFF. The Lockheed Martin Atlas rocket begins the new millennium for space launches. The vehicle has cleared the tower.

0102 GMT (8:02 p.m. EST)

T-minus 31 seconds. Launch Sequence Start.

In the next few seconds the inertial navigation unit's countdown will be started, the liquid hydrogen and liquid oxygen vent valves will be locked and the flight data recorders will be readied.

0102 GMT (8:02 p.m. EST)

T-minus 1 minute. Engines are being verified ready for flight and final status checks are under way.

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

0101 GMT (8:01 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. Engine preparations are completed.

Shortly, the rocket's inadventant separation destruct safety system will be armed, the Centaur upper stage will go to internal power and the flight termination system will be armed.

0100 GMT (8:00 p.m. EST)

T-minus 3 minutes. The water system is being readied for activation at launch pad 36B. Complex 36 was originally built in the early 1960s for the Atlas/Centaur development program. The complex supported interplanetary and communications satellite launches under NASA's sponsorship. In late 1989, NASA handed Complex 36 to the Air Force and General Dynamics for military and commercial launches. The dual pads at the complex were then readied for the new Atlas 2-series of rockets flying today.

0059 GMT (7:59 p.m. EST)

T-minus 4 minutes. The Atlas booster stage and Flight Termination System have gone on internal power.

0058 GMT (7:58 p.m. EST)

T-minus 5 minutes and counting. The countdown has resumed for launch of Atlas/Centaur-138 with the Defense Satellite Communications System B8 spacecraft for the U.S. Air Force.

0057 GMT (7:57 p.m. EST)

Countdown will be restarted in one minute. The Atlas rocket is now six minutes away from liftoff at Cape Canaveral Air Station in Florida.

0056 GMT (7:56 p.m. EST)

The launch team has reported all systems are go for launch. All the polls are completed and launch is set for 8:03 p.m. EST (0103 GMT).

0054 GMT (7:54 p.m. EST)

Shortly final readiness polls of the launch team and senior management will be conducted to give the OK to resume the countdown at 7:58 p.m. EST.

0053 GMT (7:53 p.m. EST)

Ground-level winds continue to remain acceptable for launch of the Atlas rocket in ten minutes. The communications loops between launch team members are quiet as the planned countdown hold continues at T-minus 5 minutes.

0048 GMT (7:48 p.m. EST)

Now 15 minutes away from the scheduled launch of a Lockheed Martin Atlas 2A rocket from Cape Canaveral Air Station in Florida. There are no problems being worked.

The mission to place the DSCS B8 communications satellite into the proper geosynchronous transfer orbit will occur in a two-step fashion. About 10 minutes into the launch, the Centaur upper stage should achieve a parking orbit around the Earth. The nominal orbital parameters include a perigee altitude of 80 nautical miles, apogee altitude of 485 nautical miles and inclination of 29.3 degrees to the equator. The Centaur will later perform a second firing to boost the DSCS spacecraft into a transfer orbit at separation with a perigee of 123 nautical miles, apogee of 19,278 nautical miles and inclination of 26.5 degrees.

DSCS B8 will use its onboard kick motor to circularize its orbit at geostationary altitude and decrease the inclination.

0044 GMT (7:44 p.m. EST)

The Atlas and Centaur liquid oxygen tanks and Centaur liquid hydrogen tanks are reported at flight level.

0043 GMT (7:43 p.m. EST)

T-minus 5 minutes and holding. Countdown clocks have entered the final planned built-in hold for tonight's launch attempt. During this 15-minute period, the launch team will have a chance to catch up on any work that could be running behind schedule. In addition, managers will poll various members of the launch team to ensure all systems are ready for liftoff. The count should resume at 7:58 p.m. EST (0058 GMT).

Also, the launch team reports the special test of the Flight Termination System is complete and results are acceptable.

0038 GMT (7:38 p.m. EST)

T-minus 10 minutes and counting. The countdown will enter a 10-minute planned hold five minutes from now. That hold will last 15 minutes leading toward a liftoff of 8:03 p.m. EST (0103 GMT).

0032 GMT (7:32 p.m. EST)

A special test is being planned to verify the rocket's Flight Termination System is healthy. The FTS is a critical system and must work properly for the rocket to be cleared for launch. It would be used to destroy the rocket in the event of an accident during flight.

0028 GMT (7:28 p.m. EST)

Launch weather officer Jim Sardonia reports ground winds are still looking promising. Currently at launch pad 36A the winds are averaging between 18 and 20 knots. The limit for launch is 26 knots, and although there could an isolated spike at or above the limit, conditions do look favorable for liftoff tonight. Other weather criteria are green.

0027 GMT (7:27 p.m. EST)

A problem was encountered with the Flight Termination System self-test. A workaround is being developed. Also the POGO suppression system, used to absorb the rocket's bounce at ignition, is being pressurized.

0025 GMT (7:25 p.m. EST)

The loading of the Atlas booster and Centaur upper stage with super-cold cryogenic propellant is now completed. However, give the cold nature of the liquid oxygen and liquid hydrogen, the cryogenics naturally boil away during the countdown. As a result, the tanks will be topped off until just minutes prior to liftoff.

0020 GMT (7:20 p.m. EST)

The payload aboard the Atlas 2A rocket tonight is the $200 million Defense Satellite Communications System B8 spacecraft for the U.S. Air Force. The craft is the 11th to be launched in the current DSCS 3 generation. Following the launch, the satellite will undergo on-orbit maneuvering and testing before entering service in mid-May.

DSCS B8 is the first of fourth remaining DSCS spacecraft to be launched with the Service Life Enhancement Program, or SLEP, updgrades. The enhancements provide more power to the satellites and increase their communications relay capabilities.

The U.S. military relies on the DSCS fleet of five primary spacecraft to cover different parts of the globe for communications between commanders and troops in the field. DSCS provides super-high frequency, uninterrupted and secure voice and data communications.

0016 GMT (7:16 p.m. EST)

The Flight Termination System self-test has now about to start. The FTS would be used to destroy the Atlas rocket should problem occur during the launch.

0014 GMT (7:14 p.m. EST)

Atlas liquid oxygen tank is above 90 percent full and Centaur liquid hydrogen tank is at 80 percent. The countdown continues toward the scheduled 8:03 p.m. EST (0103 GMT) launch.

0009 GMT (7:09 p.m. EST)

Atlas liquid oxygen tank is now at 80 percent and Centaur liquid hydrogen is 50 percent full.

0000 GMT (7:00 p.m. EST)

With the liquid oxygen tank inside the Centaur upper stage basically filled and Atlas oxygen loading continuing, the launch team is now beginning liquid hydrogen fueling for the Centaur. Liftoff remains set to occur at 8:03 p.m. EST (0103 GMT).

THURSDAY, JANUARY 20, 2000
2350 GMT (6:50 p.m. EST)

Loading of super-cold liquid oxygen into the Atlas booster stage is underway. The rocket's silver exterior is now turning a frosty white with a thin layer of ice from the oxygen.

2349 GMT (6:49 p.m. EST)

Since the earlier delay with ground support equipment, the countdown is marching ahead toward the planned 8:03 p.m. EST (0103 GMT) liftoff. There are no problems being worked with the rocket or DSCS spacecraft. In addition, weather conditions are looking better and winds have decreased significantly since earlier today.

2343 GMT (6:43 p.m. EST)

Final alignment of the Atlas rocket's inertial navigation unit has been completed and flight control system final preps are starting. Centaur liquid oxygen is now at 90 percent.

2341 GMT (6:41 p.m. EST)

Centaur liquid oxygen is now 80 percent full.

2338 GMT (6:38 p.m. EST)

Chilldown of the liquid hydrogen fuel lines at pad 36A is starting to prepare for filling the Centaur stage. Also, the blockhouse doors are being sealed at this time at Complex 36.

2333 GMT (6:33 p.m. EST)

Forty percent of the Centaur liquid oxygen tank has been loaded.

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

The Centaur liquid oxygen tnak is now 10 percent full.

2317 GMT (6:17 p.m. EST)

With fuel lines properly conditioned, the go has been given to start pumping super-cold liquid oxygen into the Centaur upper stage. This is the first of three fuel operations to occur during the countdown tonight. Later the Atlas stage will be loaded with liquid oxygen and Centaur will be fueled with liquid hydrogen.

RP-1 fuel, a highly refined kerosene, was loaded aboard the Atlas stage last week.

2312 GMT (6:12 p.m. EST)

To look ahead over the next hour or so in the countdown, the timeline leading to the new 8:03 p.m. EST launch time shows the start of liquid oxygen tanking to Centaur at 6:17 p.m. EST, Atlas liquid oxygen loading beginning at 6:43 p.m. EST and Centaur liquid hydrogen fueling starting at 6:57 p.m. EST. As always, these times are approximate and could change.

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

Technicians report the mobile service tower is now parked a short distance away from the rocket for launch. Soon the launch pad complex will be cleared of all workers.

2305 GMT (6:05 p.m. EST)

Checks of the wind-damper arm between the Atlas rocket and launch pad umbilical tower have been completed. Also the Range has started safe and arm testing.

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

The chilling of liquid oxygen fuel lines is now beginning in preparation for loading the super-cold cryogenics into the Centaur upper stage shortly.

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

T-minus 105 minutes and counting. Countdown clocks are ticking again for launch of the AC-138 Atlas 2A rocket with the DSCS B8 spacecraft. Another hold is planned at T-minus 5 minutes leading to the new liftoff time of 8:03 p.m. EST (0103 GMT).

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

A readiness poll of launch team has been completed and the go was given for fueling the Atlas booster and Centaur upper stage. Rollback of the mobile service structure is continuing and should be completed in the next few minutes. Countdown clocks will resume from T-minus 105 minutes at 6:03 p.m. EST (2303 GMT).

2242 GMT (5:42 p.m. EST)

In a surprise turn of events, the ground-level winds at launch pad 36A are cooperating and officials have decided to roll the protective mobile service tower away from the Atlas rocket at this time. Earlier today, weather officials predicted strong winds at this point in the day, preventing tower removal until later this evening.

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

The management team has decided to recommend fully retracting the mobile service tower from the Atlas rocket at this point in the countdown given the current acceptable wind conditions. Earlier, officials had thought the winds would be too strong to roll the tower away from the rocket this early in the countdown. That would have resulted in moving the tower by remote control very close to launch once the winds decreased.

2233 GMT (5:33 p.m. EST)

T-minus 105 minutes and holding. The countdown has entered a planned 30-minute hold. Launch is now set to occur at 8:03 p.m. EST (0103 GMT).

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

The decision has been made to hold as planned at T-minus 105 minutes for a 30-minute hold. This is a typical hold for any Atlas launch countdown. But since there was an unplanned hold earlier, the launch time for the Atlas rocket tonight has been delayed officially some 48-minutes, or until 8:03 p.m. EST (0103 GMT). Tonight's launch window extends until 8:39 p.m. EST (0139 GMT).

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

Air Force launch weather officer Jim Sardonia says ground-level winds have been decreasing significantly in the last hour at Cape Canaveral Air Station. He reports there are no winds above 32 knots currently around the space center. The 32-knot is limit for retraction of the mobile service tower. For launch to occur, winds cannot exceed 26 knots. In the last 25 minutes, winds even have been below the launch limit.

Overall, the weather picture is improving and there is an 80 percent chance of acceptable winds by the end of the launch window.

Meanwhile, checks have started with the C-band beacon used to track the rocket during launch and road blocks are being established at the launch complex.

2215 GMT (5:15 p.m. EST)

Lockheed Martin would like to skip the entire 30-minute planned hold at T-minus 105 minutes, which would result in a new launch time of 7:33 p.m. EST (0033 GMT). However, the U.S. Air Force has recommended a normal hold, leading to liftoff at 8:03 p.m. EST (0103 GMT).

2210 GMT (5:10 p.m. EST)

T-minus 128 minutes and counting. The countdown has resumed after this unplanned 48-minute hold. Officials are still discussing the duration of the T-minus 105 minute planned hold and new launch time.

2206 GMT (5:06 p.m. EST)

Mobile service tower removal to the temporary position around the rocket has started. The tower will remain very close to the rocket to protect the Atlas from ground-level winds. The tower will be rolled back completely to the launch position later in the countdown through remote control.

2205 GMT (5:05 p.m. EST)

The go has been given to retract the mobile service tower a slight amount. From that temporary position, the launch pad can be cleared of all workers and fueling can begin.

2150 GMT (4:50 p.m. EST)

Six of seven available video cameras at the launch pad that will be used during fuel operations have been activated as the remote control system problem is being resolved.

2143 GMT (4:43 p.m. EST)

Officials have approved a workaround plan to solve the power problem for the MST remote control system.

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

Officials believe it will take another 15 minutes or so to continue working the MST remote control system. Since the countdown is in an unplanned hold, the launch team will shorten the built-in hold at T-minus 105 minutes from 30 minutes to 20 minutes.

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

T-minus 128 minutes and holding. The countdown clock has stopped as Lockheed Martin engineers troubleshoot a problem with the mobile service tower power drive system.

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

In the latest update, Air Force launch weather officer Jim Sardonia says ground-level winds continue to be a problem for tonight's liftoff of an Atlas 2A rocket from Cape Canaveral Air Station, Florida. At the planned 7:15 p.m. EST (0015 GMT) launch time, the forecast calls for winds at 15 gusting to 28 knots. The limit is 26 knots. Overall, there is a 70 percent chance winds will be unacceptable at the opening of the 84-minute launch window.

However, winds are expected to decrease after sunset tonight and Sardonia predicts there is a 70 or 80 percent chance of allowable winds for launch after 8 p.m. EST (0100 GMT). Lockheed Martin has until 8:39 p.m. EST (0139 GMT) to launch the rocket tonight.

Also of note, officials are watching the upper level winds. The winds are upwards of 120 knots at 46,000 feet. Weather balloons are being launched to collect information during the remainder of the countdown.

Other than the winds, other weather conditions will be favorable with a temperature in the mid-60s F and clear skies. The weather reconnaissance aircraft will not be used tonight because clouds and rain will not be factors.

At launch pad 36A, the final alignment of the rocket's inertial navigation unit is starting and final pre-launch configuration of the DSCS B8 spacecraft atop the Atlas is complete.

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

Lockheed Martin officials will likely make an unprecedented effort tonight to launch an $80 million Atlas 2A rocket carrying a $200 million U.S. Air Force DSCS 3 communications satellite. Liftoff is planned for 7:15 p.m. EST (0015 GMT Friday) but could happen as late as 8:39 p.m. EST (0139 GMT). Weather officials say there is only a 30 percent chance ground-level winds decrease to acceptable limits.

The Central Florida and Cape Canaveral Air Station is experiencing very strong winds today with the passage of a cold front. Those winds are expected to violate the safety rules that govern when the protective mobile service tower can be rolled away from the rocket at pad 36A. Previously, the Lockheed Martin launch would not fuel the Atlas and Centaur upper stage until after the tower was moved away about three hours prior to liftoff. But tonight officials will allow the tower to remain around the rocket while fueling occurs, preserving the opportunity to get the Atlas airborne if winds subside. The tower would then be rolled away from the rocket by remote control about 25 minutes before launch while the countdown is holding at T-minus 5 minutes.

Weather forecasters say the winds should gradually decrease as the day goes along, particularly tonight once the front passes through the Cape area after 4 p.m. EST.

There are three weather rules that will come into play. The first is the 41-knot limit needed to permit fueling of the rocket inside the tower. That rule should not be violated and fueling should begin shortly after 5:15 p.m. EST, allowing the countdown to continue. The second factor will be the tower retraction rule, which says winds must be below 32 knots. And for launch to actually occur, the winds cannot exceed 26 knots.

"We will look at tanking in the tower because looking at weather, that will give us the best opportunity for success," said Lt. Col. Tony Goins, the U.S. Air Force launch director. "We are going to posture ourselves to be successful this evening."

Lockheed Martin tested the tanking-in-the-tower concept last year, and conducted the countdown dress rehearsal for this launch in which the rocket was fueled without removing the MST. In addition, the countdown rehearsal on Tuesday repeated the test at nearby pad 36B for the Atlas being prepared for launch next month.

The aerospace company has completed a blast analysis, studies and reviewed the positions of cameras inside the tower to ensure safety during the fueling operations.

If the decision is made to proceed with the tanking-in-the-tower plan, officials could wait until about 8:10 p.m. EST (0110 GMT) for the winds to die down, said Adrianne Laffitte, Lockheed Martin's director of Atlas operations at Cape Canaveral.

It will take about 15 minutes to roll the tower back, followed by polling the launch team to ensure all other systems are go and to complete the final five minutes of the countdown, lifting off at or near the end of tonight's window.

Other than the weather, there are no other problems being worked with the rocket, DSCS B8 satellite or ground systems. The Range countdown has started and soon the U.S. Air Force 3rd Space Launch Squadron team will arrive on console to oversee the mission.

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

Launch day is here for the first Cape Canaveral rocket flight of 2000, but bad weather could very well play the role of spoiler tonight. A Lockheed Martin Atlas 2A rocket is poised to carry a military communications satellite into orbit. However, U.S. Air Force meteorologists continue to predict a 70 percent chance weather conditions will not be acceptable for launch during a window extending from 7:15 to 8:39 p.m. EST (0015-0139 GMT Friday).

Air Force launch weather Jim Sardonia gives this report this morning:

"A significant but dry cold front will move through CCAS at around 1600L this afternoon. Surface winds will be gusty all day today and especially between 1500L and 1800L. Cloud coverage will be minimal and no rainshowers or thunderstorms are expected. The upper-level wind profile shows a persistent profile to 41,000 feet where the max winds are 120 knots. The main concern today will be the peak winds at SLC 36A gusting above the 26 knot launch constraint after frontal passage."

The latest launch time forecast calls for cumulus clouds scattered at 3,000 feet, visibility of 7 miles or better, northwesterly winds 20 gusting to 30 knots at the 90-foot level of pad, a temperature of 59 to 61 degrees F and relative humidity of 70 percent.

Overall, there is a 70 percent chance of weather rule violation due to the ground winds.

Weather does improve to near-perfect conditions if the launch is delayed 24 hours.

At launch pad 36A, the rocket is being powered up and the countdown clocks are beginning tick toward liftoff.

We will next update later this afternoon following the pre-launch press briefing.

WEDNESDAY, JANUARY 19, 2000
2220 GMT (5:20 p.m. EST)

The Flight Readiness Review is over and an Atlas rocket has been cleared for liftoff on Thursday with a U.S. Air Force DSCS communications satellite onboard. However, there is a potential problem with the weather. Meteorologists say there is a 70 percent chance bad weather will delay the launch. See our earlier update from today for more details.

Check back Thursday for comprehensive live coverage of the final countdown and launch.

1545 GMT (10:45 a.m. EST)

The weather forecast has taken a nose dive for Thursday night's launch of an Atlas 2A rocket from Cape Canaveral Air Station in Florida. Earlier predictions indicated a 60 percent chance of meeting the launch weather rules during Thursday's window extending from 7:15 to 8:39 p.m. EST (0015-0139 GMT Friday). But the latest weather report issued this morning shows only a 30 percent chance of acceptable conditions for launch.

Air Force launch weather Jim Sardonia gives this update:

"Computer models are now converging on a solution in moving a significant cold front through CCAS just prior to the opening of the launch window Thursday night. Surface winds will be gusty along and behind this front and there will be a slight increase in the chance of scattered rainshowers over CCAS during frontal passage. Rainshowers will be few and no thunderstorms are expected, however thick cloud bands associated with the cold front will likely violate the triggered lightning launch commit criteria (rules). The main concern on launch day will be the peak winds at SLC 36A gusting above the 26 knot launch constraint after frontal passage. Secondary concerns include thick layered clouds and the proximity to building cumulus clouds and rainshowers along the frontal boundary."

The launch time forecast calls for cumulus clouds scattered at 3,000 feet, altocumulus clouds scattered at 12,000 feet and broken cirrostratus clouds at 25,000 feet, visibility of 7 miles or better, northwesterly winds 18 gusting to 28 knots at the 90-foot level of pad, a temperature of 59 to 61 degrees F, relative humidity of 70 percent and widely afternoon rainshowers during frontal passage.

Overall, there is a 70 percent chance of strong ground winds, thick layered clouds and nearby cumulus clouds will keep the Atlas rocket on Earth.

If the launch is postponed 24 hours, the forecast improves to 90 percent chance of good conditions with the only concern being ground winds. For a 48-hour delay, the forecast calls for an 80 percent chance of acceptable weather with the concern being cumulus clouds.

At Cape Canaveral today officials are holding the final readiness reviews to give the approval for launch.

We will provide the next update late this afternoon, Eastern Time, with results from the Flight Readiness Review.

TUESDAY, JANUARY 18, 2000
2350 GMT (6:50 p.m. EST)

The stage is set this week for Lockheed Martin's first Atlas rocket launch of 2000. The AC-138 vehicle, an Atlas 2A rocket, will carry the U.S. Air Force Defense Satellite Communications System (DSCS-B8) spacecraft into geosynchronous transfer orbit.

Liftoff from pad 36A at Cape Canaveral Air Station is planned to occur on Thursday at 7:15 p.m. EST (0015 GMT Friday), the opening of an 84-minute window.

The weather forecast calls for a 60 percent chance of acceptable conditions due to concerns over cumulus clouds, rainshowers and gusty winds. Air Force launch weather Jim Sardonia gives this overview:

"A weak cold front from the Tennessee valley is now not expected to move into Florida until Thursday afternoon. This will increase the surface winds and increase the chance of scattered rainshowers along the frontal boundary as it passes over CCAS during the launch countdown. Confidence is low however, in the accuracy of the computer models, so expect changes in the launch forecast. The main concerns on launch day include the possibility of peak winds at pad 36A approaching the 26 knot launch constraint and the proximity to building cumulus clouds and rainshowers along the frontal boundary."

The launch time forecast calls for cumulus clouds scattered at 3,000 feet, altocumulus clouds scattered at 12,000 feet and broken cirrostratus clouds at 25,000 feet, visibility of 7 miles or better, northwesterly winds 15 gusting to 25 knots at the 90-foot level of pad, a temperature of 60 to 62 degrees F, relative humidity of 75 percent and widely scattered light rainshowers along the front.

If the launch is postponed 24 hours, the forecast improves to 90 percent chance of good conditions with the only concern being cumulus clouds. For a 48-hour delay, the forecast calls for an 80 percent chance of acceptable weather with the concerns being cumulus clouds and rainshowers along the stalled frontal boundary.

Launch officials spent Tuesday going through paperwork and preparing for Wednesday's readiness meetings. The Lockheed Martin launch readiness review is planned for 7:30 a.m. EST and the multi-agency flight readiness review to clear the Atlas 2A rocket and DSCS spacecraft for liftoff is planned for 2 p.m. EST.

The launch pad was closed for part of Tuesday because the Atlas rocket on nearby pad 36B was undergoing a countdown dress rehearsal for the planned February 3 launch of the Spanish Hispasat 1C satellite.

DSCS B8 will become the 11th spacecraft launched under the DSCS-3 program, providing global communications for military users. The craft will use its Integrated Apogee Boost Subsystem, or IABS, onboard rocket motor to achieve geostationary orbit. The U.S. Air Force plans to position the satellite along the equator at 175 degrees East longitude.