BY JUSTIN RAY

November 22, 1999 -- Follow the launch of the U.S. Navy's UHF Follow-On communications satellite aboard a Lockheed Martin Atlas 2A. Reload this page for the very latest on the mission.

0458 GMT (2358 EST)

Hughes Space and Communications officials report ground controllers have established contact with the UHF F10 satellite following its successful launch tonight. Controllers say the satellite appears healthy.

Over the coming weeks, the satellite will circularize its orbit to the geostationary altitude 22,300 miles above the Earth's equator with a series of apogee engine firings. Later, the craft's solar arrays and antennas will be deployed. Testing will follow to check the satellite's systems and communications payload. Handover of satellite control from builder Hughes to the U.S. government is expected in late January.

This will conclude our live coverage of AC-136/UHF F10.

0438 GMT (2338 EST)

Lockheed Martin has provided the orbital data following spacecraft separation, which indicates a very successfully deployment for UHF F10. The apogee is 14,186.644 nautical miles of the expected 14,183 nautical miles, a perigee of 154.797 nautical miles of expected 155 nautical miles and inclination of 27.0053 degrees for the nominal of 27 degrees.

See our QuickTime video of the launch. The file is 198K.

0433 GMT (2333 EST)

SPACECRAFT SEPARATION. The U.S. Navy's Ultra High Frequency Follow-On F10 communications satellite has separated from the Centaur upper stage following tonight's successful launch of the Lockheed Martin Atlas 2A rocket. The launch of AC-136 marks the 45th consecutive success for Atlas rockets dating back to 1993.

0432 GMT (2332 EST)

T+plus 26 minutes. Spinup of the satellite atop the Centaur is continuing. No problems reported. Just over a minute to spacecraft separation.

0430 GMT (2330 EST)

T+plus 24 minutes. The second burn of the Centaur upper stage is complete, boosting the UHF F10 spacecraft into the intended transfer orbit. The stage will now provide the the necessary spinning and pointing attitude in preparation for UHF F10 separation. Payload deployment will occur 27 minutes, 3 seconds into flight.

0428 GMT (2328 EST)

T+plus 22 minutes, 45 seconds. The twin engines on Centaur are firing again as the vehicle passes just north of the equator. This second Centaur burn will last for another 66 seconds until all the onboard fuel is depleted.

0424 GMT (2324 EST)

T+plus 18 minutes. The vehicle continues in a nominal coast phase. The next major event will be restart of Centaur at T+plus 22 minutes, 24 seconds. Spacecraft separation is expected 27 minutes, 3 seconds after launch.

0418 GMT (2318 EST)

T+plus 12 minutes. Officials report the parking orbit achieved tonight was near perfect. The vehicle is in an orbit with an apogee of 589 nautical miles and perigee of 91.9 nautical miles.

0416 GMT (2316 EST)

T+plus 10 minutes. The first burn of the Centaur has been completed. Centaur, with UHF F10 attached, is in an elliptical parking orbit. The duo will now quietly coast now for the next 12 minutes.

0413 GMT (2313 EST)

T+plus 7 minutes. Antigua Island tracking station has acquired the rocket. Vehicle continues right on the predicted track. Centaur engines firing as expected.

0411 GMT (2311 EST)

T+plus 5 minutes. In the last half minute, the Atlas sustainer engine was shutdown and the Atlas stage has separated from the Centaur upper stage. Centaur ignition confirmed. Centaur now in the longer of its two scheduled firings.

0409 GMT (2309 EST)

T+plus 3 minutes, 50 seconds. The payload fairing has been jettisoned. Altitude 56 nautical miles, downrange distance 122 nautical miles, speed 6,600 miles per hour.

0409 GMT (2309 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.

0407 GMT (2307 EST)

T+plus 1 minute. Vehicle reported right on the range track. Speed over 500 miles per hour.

0406 GMT (2306 EST)

LIFTOFF. Liftoff of the Lockheed Martin Atlas rocket - advancing U.S. Naval communications with the tenth UHF spacecraft. The vehicle has cleared the tower.

0405 GMT (2305 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.

0405 GMT (2305 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 and the ignition enable switch was closed.

0404 GMT (2304 EST)

T-minus 2 minutes. Pressurization of the Atlas/Centaur vehicle has started. Tanks now being brought to proper pressure levels for flight.

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.

0403 GMT (2303 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.

0402 GMT (2302 EST)

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

0401 GMT (2301 EST)

T-minus 5 minutes and counting. Clocks are now proceeding toward liftoff of Atlas/Centaur-136 with the Ultra High Frequency Follow-On F10 communications satellite for the U.S. Navy and Hughes Space and Communications.

0400 GMT (2300 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.

0359 GMT (2259 EST)

A readiness poll has been completed and the launch team reports it is ready to restart the countdown as planned at the end of this built-in hold at 11:01 p.m. EST. Launch remains set to occur at 11:06 p.m. EST (0406 GMT). The Atlas rocket, UHF satellite, Eastern Range and weather are go.

0356 GMT (2256 EST)

The UHF Follow-On F10 spacecraft is switching to internal power at this time. Liftoff is now 10 minutes away.

0351 GMT (2251 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 reported.

The mission to place the UHF F10 communications satellite into the proper sub-synchronous 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 92 nautical miles, apogee altitude of 590 nautical miles and inclination of 28.9 degrees to the equator. The Centaur will later perform a second firing to boost the UHF spacecraft into a transfer orbit at separation with a perigee of 155 nautical miles, apogee of 14,129 nautical miles and inclination of 27.0 degrees.

UHF F10 will conduct a series of altitude raising burns during its first days in space to reach geostationary orbit 22,300 miles above the Earth's equator.

0346 GMT (2246 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 11:01 p.m. EST (0401 GMT).

The Atlas booster and Centaur upper stage are now fully fueled for launch. But given the super-cold temperatures of the liquid oxygen and hydrogen aboard the vehicle, the cryogenics will be replenished as the countdown continues. The Atlas was loaded earlier with its RP-1 fuel, a highly refined kerosene.

0338 GMT (2238 EST)

Air Force launch weather officer Jim Sardonia has given officials the final pre-launch weather briefing. He reported that all weather conditions are currently acceptable and expected remain so for launch at 11:06 p.m. EST.

0336 GMT (2236 EST)

Now 30 minutes away from liftoff of AC-136 and the UHF F10 communications satellite from Cape Canaveral Air Station, Florida.

0330 GMT (2230 EST)

The self test of the Flight Termination System has been completed and the POGO suppression system, used to absorb the rocket's bounce at ignition, is being pressurized.

0321 GMT (2221 EST)

T-minus 30 minutes and counting. The countdown for launch of Atlas/Centaur-136 is proceeding as planned and on schedule tonight at Cape Canaveral Air Station. Launch is now 45 minutes away. One additional built-in hold, lasting 15 minutes, is planned at the T-minus 5 minute point.

0319 GMT (2219 EST)

The Centaur liquid hydrogen tank now 97 percent full, Atlas liquid oxygen at flight level and the Flight Termination System self-test has now started.

0308 GMT (2208 EST)

Centaur liquid hydrogen at 80 percent.

0300 GMT (2200 EST)

Atlas liquid oxygen tank now at 98 percent full and Centaur liquid oxygen at flight level.

0256 GMT (2156 EST)

Liquid hydrogen now flowing into the Centaur upper stage.

0253 GMT (2153 EST)

Centaur liquid hydrogen chilldown reported complete, clearing the way to begin LH2 tanking.

0251 GMT (2151 EST)

Atlas liquid oxygen now at 50 percent as the countdown passes T-minus 60 minutes. The countdown clock will continue to T-minus 5 minutes where a 15-minute planned hold is scheduled. There are no problems to speak of tonight and launch remains set for 11:06 p.m. EST (0406 GMT on Tuesday).

0247 GMT (2147 EST)

The Centaur liquid oxygen tank has been filled to 95 percent and controllers are beginning top off the supply. Atlas booster stage liquid oxygen is now at 20 percent. Also, the rocket's inertial measurement unit pre-flight alignment has been completed.

0236 GMT (2136 EST)

Preparations for the starting of liquid hydrogen fueling are now underway. The Centaur liquid oxygen tank is 70 percent full. The blockhouse door is being sealed. Shortly the Atlas first stage will be loaded with its load of liquid oxygen.

0226 GMT (2126 EST)

The Centaur liquid oxygen tank is now 10 percent full.

0219 GMT (2119 EST)

The launch team has been given a "go" to start loading of supercold liquid oxygen aboard the Centaur upper stage.

0206 GMT (2106 EST)

The countdown clocks have resumed ticking from the T-105 minute point after a 30-minute built-in hold. Preparations for fueling of the Centaur stage are underway.

0203 GMT (2103 EST)

The launch team has reported its readiness to begin fueling of the rocket's Centaur upper stage.

0147 GMT (2047 EST)

The mobile service tower at launch pad 36B is now in its fully retracted position in readiness for tonight's launch.

0138 GMT (2038 EST)

The countdown is at T-105 minutes and holding. This is a planned 30-minute built-in hold. Liftoff remains scheduled for 0406 GMT (11:06 p.m. EST).

0133 GMT (2033 EST)

In his latest weather briefing at T-115 minutes, Jim Sardonia reports little change in his forecast for tonight's planned launch. All launch commit criteria are "green" and are expected to remain so through to the end of the launch window. The temperature at the pad is currently 69°F and wind gusts are less than 10 knots. Upper level winds have been smooth throughout the day and are not expected to be a problem.

0112 GMT (2012 EST)

The Mobile Service Tower at launch pad 36B has begun its slow move away from the Atlas 2A launch vehicle.

0059 GMT (1959 EST)

The range has informed the launch team that this launch attempt will not be affected by any COLAs (potential collisions with spacecraft already in orbit) or threats from wind blown debris in the event of a launch accident.

0054 GMT (1954 EST)

The Integrated Launch Operations for the launch of AC-136 with the U.S. Navy's UHF F/O F10 satellite has begun at the T-minus 150 minute mark. A few moments ago the launch team gave its approval to move the gantry-like mobile service tower away from the rocket at about 8:07 p.m. EST.

U.S. Air Force weather officer Jim Sardonia has briefed the launch team on the expected weather for tonight's planned liftoff. All conditions are "green" and expected to remain so throughout the count. There remains an 80 percent chance of acceptable weather for launch. The only concern is for coastal rain showers.

2315 GMT (1815 EST)

Lockheed Martin is pressing ahead with final pre-launch preparations for tonight's mission of an Atlas rocket at Cape Canaveral. Officials say there are no major problems being worked and liftoff remains on schedule for 11:06 p.m. EST (0406 GMT on Tuesday).

The launch team will begin the Integrated Launch Operations for AC-136 at 7:52 p.m. EST from the T-minus 150 minute mark. As the final countdown gets under way, workers will roll the mobile service tower away from the rocket at about 8:07 p.m. EST. The count contains 45 minutes of built-in hold time leading toward the opening of the two-hour launch window.

1740 GMT (1240 EST)

With a battery problem resolved, Lockheed Martin is again preparing to launch an Atlas 2A rocket from Cape Canaveral Air Station, Florida. Liftoff is scheduled for tonight at 11:06 p.m. EST (0406 GMT on Tuesday). Air Force weather forecasters say there is an 80 percent chance of good conditions for launch.

The mission, which will place the U.S. Navy's Ultra High Frequency Follow-On F10 communications satellite into space, was delayed 24 hours so workers could replace the Atlas rocket's main battery. The battery is used to supply the booster with power following liftoff. But during the countdown on Sunday, the launch team noted a voltage drop from the battery. Troubleshooting overnight determined the small voltage drain was caused by ground support equipment and not an actual problem with the battery itself. However, the battery was replaced with a spare and the problem has been resolved, International Launch Services spokeswoman Julie Andrews said.

Meanwhile, workers are currently making repairs to a broken valve in the 30-inch water line that feeds the launch pad. The fix should be completed in time for tonight's launch attempt.

0203 GMT (2103 EST)

Lockheed Martin officials have called a scrub for tonight's attempt to launch an Atlas 2A rocket carrying the UHF F10 communications satellite. During the Intergrated Launch Operations, which began at 7:54 p.m. EST (0054 GMT), the launch team was working a series of problems. In the end, a faulty main battery aboard the Atlas booster forced the launch to be postponed at approximately 8:50 p.m. EST (0150 GMT), or just over two hours before launch time. Workers said it would probably take seven hours to replace the battery, much longer than tonight's available two-hour launch window. Lockheed Martin has tentatively rescheduled the mission for Monday at 11:06 p.m. EST (0406 GMT on Tuesday).

Other problems the team were working included a broken valve in the 30-inch water line that feeds the sound suppression system at launch pad 36B and gusty winds that prevented the mobile service tower from being retracted.

0200 GMT (2100 EST)

SCRUB! A battery problem has forced Lockheed Martin to scrub tonight's planned launch. More later.

SUNDAY, NOVEMBER 21, 1999
1605 GMT (1105 EST)

A Lockheed Martin Atlas 2A rocket is poised at Cape Canaveral Air Station to launch the Ultra High Frequency Follow-On F10 spacecraft for Hughes Space and Communications and the U.S. Navy. Liftoff from pad 36B is scheduled for tonight at 11:09 p.m. EST (0409 GMT on Monday), at the opening of a two-hour launch window.

The main concern threatening an on time launch had been Tropical Storm Lenny. The system forced the closure of a crucial downrange tracking station on the island of Antigua. The site is used to relay data from the rocket to the Cape and send destruct signals from the Cape to the rocket if a mishap occurs in flight. But Lenny moved away from the Caribbean island on Saturday, allowing the station to be reopened. U.S. Air Force officials reported today that the station was ready to support the launch as planned.

The countdown clocks will begin ticking later today. The full launch team will arrive on console to begin the Integrated Launch Operations at 7:54 p.m. EST (0054 GMT on Monday). During the following 3 1/4 hours, the mobile service tower at pad 36B will be retracted from the rocket and super-cold propellant and oxidizer will be loaded aboard the Atlas and Centaur upper stage.

Air Force launch weather officer Jim Sardonia said Sunday there is a 60 percent chance of acceptable conditions during the launch window. The main concerns will be coastal rainshowers and thick layered clouds.

Here is the latest weather forecast generated by the Air Force:

"The weak cold front that dissolved in the Florida peninsula yesterday has reorganized into a strong upper-level low in southern Georgia. The energy associated with this low has created a very unstable atmosphere in east-central Florida producing numerous rainshowers along the coast and some isolated thunderstorms over the ocean. With easterly onshore flow today, these showers will pass through CCAS throughout the day, with some brief periods of moderate to heavy rainfall. The edge of this upper-level low is expected to sweep through the local area tonight bringing thick layered clouds and the slight chance of an isolated thunderstorm in vicinity, possibly during MST tower roll operations (1900-2200 Local). Conditions are expected to improve before the beginning of the launch window, after the low passes through the local area. Surface winds are not as much a concern at this time. The main concern today is the possibility of rainshowers and isolated thunderstorms before the beginning of the launch window, during MST tower roll operations. Scattered rainshowers and thick layered clouds are also possible during the launch window."

Launch time conditions are expected to include cumulus clouds scattered at 3,000 feet, layered stratocumulus clouds broken at 2,500 feet and altocumulus clouds broken at 10,000 feet, visibility of 5 miles, northeasterly winds at 12 gusting to 22 knots, a temperature of 67 to 69 degrees F, relative humidty of 80 percent and coastal rainshowers.