BY SPACEFLIGHT NOW

July 28, 2000 -- Follow the countdown and flight of the Sea Launch Zenit 3SL rocket with PanAmSat's PAS-9 communications satellite. Reload this page for the very latest on the mission.

0027 GMT (8:27 p.m. EDT)

"Sea Launch is back!" That was the message from president Will Trafton moments ago. PAS-9's signal has been acquired through a tracking station in Sydney, Australia, confirming it is alive and in the correct orbit. This successful mission is Sea Launch's first since a failure four months ago.

Read our full story on the launch.

2352 GMT (7:52 p.m. EDT)

T+plus 70 minutes. SPACECRAFT SEPARATION! PanAmSat's PAS-9 communications satellite has separated from the upper stage of the Sea Launch rocket, completing today's mission. Sea Launch has returned to flight with an apparently successful flight, delivering the PAS-9 satellite into the desired geosynchronous transfer orbit around Earth.

Over the next few minutes, ground controllers should acquire the first signals from PAS-9, confirming the craft's health. In the coming weeks the satellite will boost itself into geostationary orbit 22,300 miles above the planet, deploy the solar arrays and communications antennas and undergo an extensive checkout of onboard systems before entering service. Satellite builder Hughes Space and Communications will conduct the initial work to ready PAS-9 for commercial operations before handing it over to PanAmSat in geostationary orbit at 58 degrees West longitude.

2350 GMT (7:50 p.m. EDT)

T+plus 68 minutes. The rocket has passed out of range from NASA's orbiting fleet of Tracking and Data Relay Satellite System, ending the live data stream to ground officials as expected. However, a Russian ground station might be able to confirm spacecraft separation in the next two minutes.

2342 GMT (7:42 p.m. EDT)

T+plus 60 minutes. Block DM shutdown confirmed as planned. The second burn of the upper stage is now finished, completed the powered phase of today's launch. The stage will now beginning a small spinup for deployment of PAS-9. Spacecraft separation is expected in just under 10 minutes from now.

2340 GMT (7:40 p.m. EDT)

T+plus 58 minutes. Main engine pressures normal.

2338 GMT (7:38 p.m. EDT)

T+plus 56 minutes, 30 seconds. Less than three minutes remaining in the Block DM's second burn as the vehicle cruises high above central Africa.

2337 GMT (7:37 p.m. EDT)

T+plus 55 minutes, 30 seconds. Performance of the upper stage engine reported normal.

2336 GMT (7:36 p.m. EDT)

T+plus 54 minutes, 10 seconds. The Block DM's engine is now firing again to deliver the PAS-9 satellite into the desired geosynchronous transfer orbit around Earth today. This burn should last until T+plus 59 minutes, 14 seconds.

2331 GMT (7:31 p.m. EDT)

T+plus 49 minutes. Now five minutes from the restart of the Block DM upper stage. The rocket is about to fly high above the western coast of Africa along the equator.

2312 GMT (7:12 p.m. EDT)

T+plus 30 minutes. The coast period of today's launch continues as the rocket swings around Earth in the preliminary parking orbit. This coast will last another 24 minutes before the Block DM upper stage's engine restarts.

Sea Launch Program Manager Tim Hansen just reported, "Everything looks absolutely perfect."

2258 GMT (6:58 p.m. EDT)

T+plus 16 minutes. The combined Block DM stage and PAS-9 satellite are now coasting through space, beginning a 39-minute quiet period before the restart. Block DM reignition is expected at T+plus 53 minutes, 57 seconds into flight. Release of the satellite to complete the launch is expected at T+plous 69 minutes, 54 seconds.

The official liftoff time today was 2242:00 GMT. No problems were reported during the first part of this satellite-delivery mission, which is Sea Launch's first since a failure in March.

The only snag was the lack of live video of the launch. The rocket was only seen in one camera view and that was lost at ignition. The usual launch view provided in past Sea Launch missions from the command ship three miles away was never shown.

2257 GMT (6:57 p.m. EDT)

T+plus 15 minutes. The Block DM upper stage has completed its first planned firing to deliver the PAS-9 communications satellite into an initial parking orbit around Earth.

2256 GMT (6:56 p.m. EDT)

T+plus 14 minutes. The flight still reported to be going according to plan. The Block DM should complete its first burn in less than a minute from now.

2254 GMT (6:54 p.m. EDT)

T+plus 12 minutes. Officials report the Odyssey launch platform appears to be in good shape after today's liftoff according to an inspection from a chopper.

2252 GMT (6:52 p.m. EDT)

T+plus 10 minutes, 45 seconds. The upper stage is in the first of two planned firings to loft the PAS-9 spacecraft into a geosynchronous transfer orbit.

2251 GMT (6:51 p.m. EDT)

T+plus 9 minutes, 45 seconds. The adapter on the bottom of the Block DM has been jettisoned and the upper stage's single engine has ignited.

2251 GMT (6:51 p.m. EDT)

T+plus 9 minutes, 30 seconds. The second stage has completed its job and separation from the upper stage has occurred.

2250 GMT (6:50 p.m. EDT)

T+plus 8 minutes, 15 seconds. Less than a minute left in the second stage burn. No problems have been reported so far in this launch and the rocket remains on course.

2249 GMT (6:49 p.m. EDT)

T+plus 7 minutes, 15 seconds. Throttling of the second stage has occurred to keep gravity forces within limits against the vehicle and PAS-9 spacecraft.

2248 GMT (6:48 p.m. EDT)

T+plus 6 minutes, 30 seconds. The second stage engine still firing and flight stabilization reported nominal.

2246 GMT (6:46 p.m. EDT)

T+plus 4 minutes, 30 seconds. Officials confirm activities are going as planned, however Separation of the rocket's payload fairing -- the nose cone enclosing the PAS-9 spacecraft during atmospheric ascent -- took place.

2245 GMT (6:45 p.m. EDT)

T+plus 3 minutes. Pressures in the second stage RD-120 engine and vernier steering thruster are reported normal.

2244 GMT (6:44 p.m. EDT)

T+plus 2 minutes, 35 seconds. The first stage RD-171 engine has shutdown and stage jettison confirmed. The second stage engine has also ignited.

2243 GMT (6:43 p.m. EDT)

T+plus 90 seconds. Flight stabilization reported normal. First stage continues to fire.

2243 GMT (6:43 p.m. EDT)

T+plus 60 seconds. The Zenit is passing through maximum dynamic pressure.

2242 GMT (6:42 p.m. EDT)

T+plus 30 seconds. Vehicle systems reported normal as the Zenit rocket heads eastward away from the Odyssey platform along the equator.

2242 GMT (6:42 p.m. EDT)

LIFTOFF! Liftoff of the Zenit 3SL rocket as Sea Launch returns to flight.

2241 GMT (6:41 p.m. EDT)

T-minus 1 minute.

2239 GMT (6:39 p.m. EDT)

T-minus 3 minutes. A final management poll has been completed and all systems were reported go for launch.

2236 GMT (6:36 p.m. EDT)

T-minus 6 minutes. All systems remain "go" for launch. The arm is about fully retracted to the hangar.

2232 GMT (6:32 p.m. EDT)

T-minus 10 minutes and counting.

2228 GMT (6:28 p.m. EDT)

T-minus 14 minutes. The PanAmSat PAS-9 spacecraft is switching to internal power for its journey into orbit today aboard the Zenit 3SL rocket. Liftoff remains set for 2242 GMT.

2226 GMT (6:26 p.m. EDT)

T-minus 16 minutes. The transporter/erector arm is now being retracted from its vertical position against the Zenit 3SL rocket. The arm was used yesterday to roll the rocket out of the hangar atop the Odyssey platform and to lift the rocket upright. Once the arm is lowered to the platform deck, it will be rolled back into the hangar and the build doors closed for launch.

2225 GMT (6:25 p.m. EDT)

T-minus 17 minutes and counting. At this point in the countdown, the transporter/erector arm will be retracted from against the rocket.

2222 GMT (6:22 p.m. EDT)

T-minus 20 minutes and counting. Fueling of the three-stage Sea Launch rocket has been reported completed with kerosene and super-cold liquid oxygen. However, LOX will be replenished through the countdown to replace that which is naturally boils away. The PAS-9 spacecraft also remains in a "go" status for liftoff, officials report.

2212 GMT (6:12 p.m. EDT)

T-minus 30 minutes and counting. A smooth countdown is continuing with no problems being reported. Today will be the fourth time Sea Launch has conducted a rocket flight from its unique ocean-based platform located at 154 degrees West longitude along the equator in the Pacific. The first two launches in 1999 were successful, but a ground software error caused the most recent mission in March to end in failure minutes after liftoff. The Zenit and its ICO communications payload crashed back to Earth, impacting several thousand miles downrange.

2206 GMT (6:06 p.m. EDT)

The mission director is taking a poll of launch team members to verify all parties are "go" to continue with the countdown. No problems were reported with the rocket, spacecraft or ground systems as the countdown ticks toward liftoff at 2242 GMT.

2200 GMT (6:00 p.m. EDT)

Fueling operations are nearing completion for the Sea Launch Zenit 3SL rocket. The 300-member launch team aboard the Sea Launch Commander ship, located about three miles away from the Odyssey platform, are monitoring vehicle systems. No technical problems are being reported and weather and sea conditions are within limits for liftoff at 2242 GMT (6:42 p.m. EDT).

Our live QuickTime streaming video broadcast is now underway.

2100 GMT (5:00 p.m. EDT)

The final countdown is underway as Sea Launch prepares for today's flight of a Zenit 3SL rocket from the Odyssey platform positioned along the equator in the Pacific Ocean. Officials have not reported any problems and the countdown clocks are ticking toward a 2242 GMT (6:42 p.m. EDT) liftoff carrying the PanAmSat PAS-9 communications satellite.

Our live reports plus streaming video broadcast will begin in one hour.

0401 GMT (12:01 a.m. EDT)

Sea Launch is set to make a crucial and widely watched return to service today as a Ukrainian-Russian Zenit 3SL rocket blasts off from an oceangoing platform in the Pacific carrying a telecommunications satellite for PanAmSat. The flight will be the first in four months for the international consortium, which suffered a botched launch in March due to software error.

Today's hour-long launch window opens at 2242 GMT (6:42 p.m. EDT).

On Saturday, while still around 500 miles from the launch site, controllers in the Sea Launch Commander Assembly and Command Ship (ACS) conducted the last of three launch rehearsals. According to Sea Launch officials, this test included the pre-launch activities to take place on Friday evening, the launch, spacecraft separation and the acquisition of the signal from the PAS-9 spacecraft.

After arriving at the launch site in the Pacific Ocean on the equator on Sunday night, the international launch team began final launch preparations that include checks of the Zenit 3SL launch vehicle, the PAS-9 payload, the launch platform and other pieces of ground support equipment.

The first order of business on Sunday night was to fill the Odyssey launch platform's ballast tanks with ocean water. This is done to help balance and anchor the converted oil drilling platform that is now used as the launch pad for Sea Launch. The entire process took around 10 hours, officials say.

On Tuesday, the 72-hour long countdown to launch began at 2242 GMT (6:42 p.m. EDT). Also on Tuesday, Sea Launch personnel positioned the Sea Launch Commander adjacent to the launch platform to set up walkway bridges between the two vessels--allowing free movement of launch team members. This allows engineers and technicians to make final pre-launch preparations in a more timely fashion. The vessels will stay close to each other up until the launch day.

During the latter part of the countdown this afternoon, the Sea Launch Commander ACS will move from its current location near Odyssey to a position around 3-1/2 miles from the launch platform for launch. This is done to ensure the safety of Sea Launch personnel and equipment if an accident occurred on the platform or shortly after launch.

Stay with Spaceflight Now for continuous reports during the final countdown and the 69-minute long flight to loft PAS-9, detailing events as they happen. We will also have QuickTime streaming video broadcast starting at 6 p.m. EDT.

TUESDAY, JULY 25, 2000

The Sea Launch Commander and Odyssey launch platform have arrived at the equator for this week's planned flight of a Zenit 3SL rocket to deliver PanAmSat's PAS-9 international telecommunications satellite into Earth orbit.

It will be Sea Launch's return-to-flight after a failure in March, and the fourth mission overall for the unique commercial space service that launches the joint Ukrainian and Russian rocket from a converted Norwegian oil drilling platform in the Pacific Ocean.

With Sunday's arrival at the launch site positioned at 154 degrees West longitude, Sea Launch reports activities are on track for liftoff on Friday. The available launch window will extend from 2242-2342 GMT (6:42 to 7:42 p.m. EDT).

Investigators determined the March 12 mishap was caused by a ground computer error, which failed to close a valve on the rocket's second stage. The open valve allowed pressure to steadily fall in the stage, ultimately causing the stage to prematurely stop firing in flight. The rocket and its ICO telephone relay satellite cargo crashed back to Earth, impacting several thousand miles downrange.

To prevent the problem from reoccurring, the ground software has been changed.

"Based on the investigation and subsequent report, we are completely confident the root cause was clearly identified," said Jim Maser, chair of the Board and chief engineer for Sea Launch. "We also identified corrective actions that address not only the ground software logic error, but also all associated process weaknesses that could have allowed such an error to go undetected."

The pre-launch preparations for the upcoming launch -- Sea Launch's third commercial mission -- began in earnest on June 12 with the delivery of PAS-9, the mission's payload, to the home port of Sea Launch in Long Beach, California. After arrival, PAS-9 went through extensive check-outs of all its electrical and environmental systems at the Payload Processing Facility. After passing all the tests, PAS-9 was fueled with its propellant and then encapsulated inside the payload fairing.

On June 28, members of the launch team for Sea Launch conducted the first of three launch dress rehearsals from the Launch Control Center aboard the Sea Launch Commander. During this first rehearsal, the launch team simulated the final 6-1/2 hours of the countdown. Also during the dress rehearsal, several problems were put into place by managers for the launch team to resolve. The second of the three rehearsals was held shortly after the departure of the Sea Launch vessels from the home port. That simulation also included the mission phase of the launch from lift-off through spacecraft separation. The third of such rehearsals will be held shortly before arrival at the launch site.

After assembling the entire payload section of the launch vehicle, the unit was rolled out from the Payload Processing Facility and was moved to the Sea Launch Commander. After arriving on the command ship, the payload unit was mated to the Russian-built Block-DM upper stage. The payload unit includes the spacecraft, payload fairing, and payload adapter.

With the Zenit 3SL fully assembled, technicians transferred the vehicle from the command and assembly ship over to the Odyssey launch platform on July 10. The rocket was rolled out of the assembly bay inside of the Sea Launch Commander, then lifted up to the hanger on the launch platform. It will stay in the hanger throughout the transit to the launch site.

The Odyssey launch platform departed the home port in Long Beach on July 13, ready for the nearly two-week journey to 154 degrees West longitude on the equator. Three days later, the Sea Launch Commander left Long Beach bound for the equator.

Both Sea Launch vessels arrived at the launch site in the Pacific on Sunday, July 23. They will spend the next few days anchoring the launch platform, filling its ballast tanks with water and erecting the launcher.

The countdown begins today at 2242 GMT (6:42 p.m. EDT) at T-minus 72 hours.

The launch will take a normal Zenit 3SL ascent profile that includes one burn of both the first and second stages and two burns of the re-startable Block-DM upper stage. Spacecraft separation should occur a little over an hour into the flight.

The 8,050-pound PAS-9 communications satellite that is set to be launch aboard the Sea Launch vehicle will be positioned in a geostationary orbit at 58 degrees West longitude. It will replace the older PAS-5 spacecraft above the Atlantic Ocean as part of PanAmSat's orbital fleet of satellites. Built by Hughes Space and Communications, PAS-9 is based upon the HS601-HP model spacecraft.

Spaceflight Now will have continuing reports this week, plus extensive live coverage during the final countdown and launch with running updates on this page and a live QuickTime streaming video broadcast.