BY JUSTIN RAY

Follow the countdown and flight of the Sea Launch Zenit 3SL rocket with the XM-1 radio broadcasting spacecraft. Reload this page for the very latest on the mission.

TUESDAY, MAY 8, 2001

"Long live Rock and Roll!" A jubilant launch team member made that exclamation on Tuesday after a Zenit 3SL rocket successfully carried XM Satellite Radio's second powerhouse broadcasting spacecraft into orbit from a floating platform in the Pacific Ocean. Read our complete launch story.

2320 GMT (7:20 p.m. EDT)

Ground controllers have received signals from the XM-1 spacecraft via a tracking site in Perth, Australia confirming the satellite is alive following its successful ride into space by Sea Launch.

Check back later tonight for a complete wrap-up story.

2315 GMT (7:15 p.m. EDT)

T+plus 65 minutes. SPACECRAFT SEPARATION! XM Satellite Radio's XM-1 "Roll" satellite has been released from the Block DM-SL upper stage to complete this seventh flight for Sea Launch. Contact with the craft through a ground station in Perth, Australia is expected in about five minutes to verify the satellite's health following its journey into orbit.

2310 GMT (7:10 p.m. EDT)

T+plus 60 minutes. One hour since the Sea Launch Zenit 3SL rocket blasted off from the Odyssey platform in the equatorial waters of the Pacific Ocean about 1,400 miles southeast of Hawaii. Spacecraft separation is about five minutes away. The deployment will occur high above the Central Indian Ocean.

2308 GMT (7:08 p.m. EDT)

T+plus 58 minutes. Cutoff of the Block DM-SL's 11D58M main engine has been confirmed. This completes the powered phase of today's launch. The stage will now coast for another 7 minutes before deploying the XM-1 satellite.

2305 GMT (7:05 p.m. EDT)

T+plus 55 minutes. Still awaiting confirmation from Sea Launch of upper stage shutdown.

2302 GMT (7:02 p.m. EDT)

T+plus 52 minutes. Just over two minutes remaining in this second burn of the upper stage.

2259 GMT (6:59 p.m. EDT)

T+plus 48 minutes, 45 seconds. The Block DM-SL upper stage is firing again for a six-and-a-half-minute burn to accelerate XM-1 into the intended geosynchronous transfer orbit.

2255 GMT (6:55 p.m. EDT)

T+plus 45 minutes. The coast period is nearing an end as the upper stage is about three minutes from reigniting.

2240 GMT (6:40 p.m. EDT)

T+plus 30 minutes. Not much to report at this point in the flight. The rocket continues in its quiet coast period. The rocket will coast above the Eastern Pacific, South America and Atlantic Ocean before upper stage restart over Africa.

2224 GMT (6:24 p.m. EDT)

T+plus 13 minutes, 33 seconds. The first of two firings by the Block DM-SL upper stage has been completed to deliver the XM-1 "Roll" spacecraft into geosynchronous transfer orbit.

The stage and attached will coast in a preliminary parking orbit around Earth for the next 34 minutes before the next firing to complete the powered phase of launch. The stage restart is due to occur at T+plus 48 minutes, 26 seconds into flight for a six-minute, six-second burn. Spacecraft deployment is scheduled for T+plus 65 minutes, 12 seconds after launch.

2223 GMT (6:23 p.m. EDT)

T+plus 12 minutes, 40 seconds. Upper stage engine pressure reported normal as the final minute of this burn continues.

2221 GMT (6:21 p.m. EDT)

T+plus 11 minutes. The Russian-made Block DM-SL upper stage will fire for another two-and-a-half minutes or so to inject the XM-1 satellite into a preliminary parking orbit. The targeted orbit should have a low point of 180 km and high point of 990 km with an inclination of 1.25 degrees to the equator.

2220 GMT (6:20 p.m. EDT)

T+plus 10 minutes. And now confirmation that the Block DM-SL upper stage has ignited for the first of two burns to deliver XM-1 into geosynchronous transfer orbit.

2219 GMT (6:19 p.m. EDT)

T+plus 9 minutes. The second stage has been jettisoned. It will impact the Pacific Ocean about 4,500 km downrange.

2217 GMT (6:17 p.m. EDT)

T+plus 7 minutes, 25 seconds. Confirmation now received of second stage RD-120 main engine cutoff. The vehicle is now coasting before separation of the stage in about a minute.

2217 GMT (6:17 p.m. EDT)

T+plus 7 minutes, 5 seconds. Second stage engine is throttling down in preparation for shut down.

2215 GMT (6:15 p.m. EDT)

T+plus 5 minutes. The second stage engine continues to fire. A smooth flight so far, officials report.

2214 GMT (6:14 p.m. EDT)

T+plus 4 minutes. The payload fairing, or nose cone, of the rocket has separated. It will impact the Pacific Ocean about 1,000 km downrange. Also, NASA's Tracking and Data Relay Satellite System has acquired signal from the Block DM-SL upper stage.

2213 GMT (6:13 p.m. EDT)

T+plus 3 minutes, 15 seconds. The first stage RD-171 engine has shutdown as planned and the spent stage was jettisoned. It will impact the Pacific Ocean about 800 km downrange. Ignition of the second stage engine has been confirmed.

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

T+plus 2 minutes. The first stage engine is being throttled to ease the dynamic loads on the rocket and XM-1 satellite.

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

T+plus 90 seconds. Zenit continues to follow the proper flight path. Official liftoff time was 2210:29.16 GMT.

2211 GMT (6:11 p.m. EDT)

T+plus 60 seconds. The Zenit is passing through maximum dynamic pressure. Engine pressures reported normal.

2210 GMT (6:10 p.m. EDT)

T+plus 20 seconds. The Zenit rocket is pitching over to the proper trajectory with a normal flight reported.

2210 GMT (6:10 p.m. EDT)

LIFTOFF! Liftoff of the Sea Launch Zenit 3SL rocket on a mission to deliver the XM Satellite Radio's "Roll" digital audio broadcasting spacecraft into orbit.

2209 GMT (6:09 p.m. EDT)

T-minus 1 minute. Now 60 seconds away from liftoff. All systems reported ready.

2208 GMT (6:08 p.m. EDT)

T-minus 2 minutes. The engine start preparations are beginning to ready the first stage RD-171 powerplant for ignition. The Russian-made engine has four nozzles and powers the rocket for the first two minutes, 24 seconds of flight.

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

T-minus 4 minutes and counting. Initial readiness checks of managers indicates all systems are "go" for an on-time launch. The final clearance for liftoff will begin at T-minus 1 minute. Meanwhile, the transporter/erector arm is now fully retracted to the hangar and the doors have been sealed. Also, XM-1 has switched to internal power.

2205 GMT (6:05 p.m. EDT)

T-minus 5 minutes and counting. Standing by for final readiness polls.

2203 GMT (6:03 p.m. EDT)

T-minus 7 minutes and counting. All continues to proceed well with the automated launch sequence. Sea Launch is not reporting any technical problems.

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

T-minus 10 minutes and counting. The weather conditions at the launch site along the equator are well within limits for liftoff just 10 minutes from now. The skies are partly cloudy, the temperature is 79 degrees F, with an eastly wind of 2.0 knots and 2-foot waves.

2158 GMT (5:58 p.m. EDT)

T-minus 12 minutes and counting. The final sweep of the launch danger area by the Sea Launch helicopter has been completed with the zone verified clear of any ships or aircraft.

2155 GMT (5:55 p.m. EDT)

T-minus 15 minutes and counting. The launch team confirms fueling of the Zenit rocket and its Block DM-SL upper stage has been completed. Temperatures and pressures are reported normal. Also, thousands of gallons of sea water are being automatically pumped into the Odyssey launch platform to keep the converted oil-drilling rig stable for today's liftoff.

2153 GMT (5:53 p.m. EDT)

T-minus 17 minutes and counting. The countdown is reaching a major milestone as the transporter/erector arm is retracted from against the rocket. The arm was used earlier to roll the rocket out of the environmentally-controlled 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.

2150 GMT (5:50 p.m. EDT)

Sea Launch is just 20 minutes away from its seventh mission and the second for XM Satellite Radio. Activities remain on schedule for liftoff at 2210 GMT to begin a 65-minute, 12-second flight to loft the 10,289-pound XM-1 radio broadcasting satellite into an egg-shaped geosynchronous transfer orbit looping from 902 km on the low end to 35,922 km on the high end with an inclination of 1.25 degrees to the equator. The Boeing-built satellite will later fire its onboard kick engine in a series of maneuvers to achieve geostationary orbit, joining XM-2 launched on March 18.

2050 GMT (4:50 p.m. EDT)

The Zenit rocket is being fueled at this hour as the countdown continues for liftoff at 2210 GMT. Our live continuous updates on the final countdown and 65-minute flight will begin at 2150 GMT.

1700 GMT (1 p.m. EDT)

Sea Launch reports all systems are go for liftoff later today of the Zenit 3SL rocket with XM-1. The countdown remains on schedule for launch at 2210 GMT from the Odyssey platform stationed at 154 degrees West longitude on the equator in the Pacific Ocean.

MONDAY, MAY 7, 2001

The Sea Launch Zenit 3SL rocket -- topped with the XM-1 radio broadcasting satellite enclosed with its nose cone -- is pointing skyward. The Ukrainian/Russian rocket was rolled out of its horizontal hangar atop the Odyssey launch platform and erected upright today.

In the final few hours of the countdown Tuesday, the rocket's stages will be loaded with kerosene fuel and super-cold liquid oxygen. The Sea Launch Commander -- which serves as the floating control center -- will be positioned about 3.5 miles from Odyssey where the 300-member launch team can oversee the activities to ready the rocket for liftoff.

Nicknamed "Roll", this second of two XM Satellite Radio spacecraft will be used to beam 100 channels of music, news and entertainment programming directly to automobiles and special radios of subscribers across the United States starting later this year. The service will cost $9.95 per month, and is a direct competitor to Sirius Satellite Radio. Sirius has already launched its three satellites and its preparing to debut commercial service.

Both XM satellites are based upon Boeing's 702 model. XM 1 weighs 10,289 pounds at launch. The craft will feature a solar array span of 132.5 feet once fully deployed and in position in geostationary orbit at 85 degrees West longitude. From there, it will relay CD-quality audio using a S-band communications payload provided by Alcatel Space of France.

Stay with Spaceflight Now for live coverage of the launch. We will provide live play-by-play updates during the final countdown and mission.

1700 GMT (1 p.m. EDT)

The Sea Launch Zenit 3SL rocket has been rolled out of its hangar atop the Odyssey platform as preparations continue for Tuesday's planned 2210 GMT (6:10 p.m. EDT) liftoff. The rocket -- riding horizontal on the special Transporter/Erector -- will be lifted upright today and connected to its launch mount.

SUNDAY, MAY 6, 2001

The Sea Launch vessels dropped anchor in the equatorial waters of the Pacific Ocean over the weekend and started the countdown for Tuesday's flight of a Zenit 3SL rocket carrying XM Satellite Radio's "Roll" digital audio broadcasting spacecraft.

The Odyssey launch platform and Commander control ship arrived at the launch site on Saturday at 154 degrees West longitude, about 1,400 miles southeast of Hawaii. Activities began in quick order to ballast Odyssey -- a converted oil drilling rig -- to its launch depth of 65 feet to ensure stability. And the 72-hour countdown was initiated. Commander pulled along side Odyssey and a bridge was erected for workers to walk from ship to ship through the final hours prior to launch. Commander will move about 3 1/2 miles away from the launch platform for safety reasons before the rocket is fueled.

Tuesday's launch opportunity begins at 2210 GMT (6:10 p.m. EDT) and extends for 45 minutes.

This launch attempt is the second for the XM-1 satellite, which was just 11 seconds from liftoff on January 8 when the countdown was aborted. Engineers called a hold due to concerns with a reading from a spacecraft system. It turned out not to be a problem, however the count has progressed to a point when the pre-ignition processes for the rocket's first stage had already begun. That meant the engine could not be used until it was refurbished -- a job not possible in the middle of the Pacific Ocean.

So the Sea Launch ships sailed back to Home Port in Long Beach, California. Officials opted to fly the XM-2 satellite first -- a launch successfully carried out on March 18. XM-1 got a new Zenit rocket for Tuesday's launch.

The "Rock" spacecraft is now in geostationary orbit 22,300 miles above Earth awaiting the arrival of "Roll" to relay up to 100 channels of radio programming directly to subscribers of the XM service across the U.S. later this summer.

Watch this page for continuous live coverage during the final portion of Tuesday's countdown and the entire climb to orbit.

SUNDAY, MARCH 18, 2001

American motorists seeking something new from their car radios received a boost Sunday when a rocket launched from a platform in the middle of the Pacific Ocean and delivered a digital audio broadcasting satellite into orbit. Read our full story on the first XM Satellite Radio launch.

SUNDAY, FEBRUARY 11, 2001

Sea Launch has decided to flip-flop the flights of its Zenit 3SL rocket carrying the two broadcasting spacecraft for XM Satellite Radio in the continuing wake of an aborted countdown January 8.

In the final 30 seconds of the count, launch team members monitoring the health of the XM-1 satellite -- nicknamed "Roll" -- noted a measurement reading out of tolerance. The countdown clocks were halted at T-minus 11 seconds, but that was after the pre-start sequence had begun for the Zenit's first stage engine.

As a result, the floating launch platform Odyssey and the Commander control ship were forced leave the equatorial launch site in the Pacific Ocean and return to Sea Launch Home Port in Long Beach, California, for engine replacement.

Tentative plans had called for the rocket's first, and possibly the second stage too, to be swapped so XM-1 could be launched on February 28.

But a new strategy was announced Friday that calls for XM-2 -- nicknamed "Rock" -- to be launched first to keep its routine pre-flight sequence on track. It is expected to be delivered to the Home Port on Monday. The liftoff is slated for March 18 with a 37.5-minute launch window opening at 2233:30 GMT (5:33:30 p.m. EST).

The XM-1 "Roll" satellite is scheduled to follow with launch around May 7.

"It just goes to show you, that you should always Rock before you Roll," Hugh Panero, XM president & CEO said in a statement.

Both craft were built Boeing Satellite Systems using the Boeing 702 model design.

XM will offer up to 100 channels of digital quality music, news, sports, talk, comedy and children's programming that will be beamed directly to subscribers' automobiles across the U.S. The monthly subscription fee will be $9.95.

XM says it still plans to debut its commercial service this summer despite the launch delays.

THURSDAY, JANUARY 11, 2001

The Sea Launch vessels have set sail for home, departing the equatorial waters of the Pacific Ocean on a voyage back to the United States so a portion of the Zenit 3SL rocket can be replaced in the wake of an aborted engine ignition sequence this week.

Once back at the Sea Launch Home Port in Long Beach, California, the international consortium plans to start a second campaign that will culminate with boosting the XM Satellite Radio "Roll" spacecraft into orbit at the end of February.

Monday's initial attempt at launch was halted at T-minus 11 seconds. The launch team was worried with a reading from the XM 1 satellite, causing the countdown to be stopped. The concern turned out to be no problem, but the abort came at such a late moment the pre-start procedures had already commenced on the rocket's Russian-made RD-171 engine.

That engine now must undergo a lengthy refurbished before it can be used again, a fact that has forced Sea Launch to replace the powerplant so the XM 1 radio broadcasting satellite can be carried aloft sooner rather than later.

And keeping with the desire to speed things along, officials have decided to actually replace the entire first stage of the Ukrainian-made Zenit rocket with another stage in storage. Sea Launch says it could also opt to switch out the second stage, if that makes the turnaround faster.

The Boeing-built satellite will remain attached to the Russian-made Block DM-SL third stage regardless of whether one or both Zenit stages get changed.

Sea Launch has tentatively set February 28 as the new liftoff date for XM 1.

TUESDAY, JANUARY 9, 2001

Sea Launch officials today decided the first stage engine on the Zenit 3SL rocket needs to be replaced because its pre-ignition sequence was started during Monday's aborted countdown. The job will require the command ship and launching platform return to port, delaying the mission until February 28.

Clocks reached T-minus 11 seconds before being stopped after the launch team noted a glitch with the XM 1 satellite the rocket is to carry into orbit. The issue was quickly resolved.

But since pre-start fluids had flowed into the Russian RD-171 engine, the four-nozzle powerplant will have to be swapped out with a fresh, certified engine, officials said. That job requires the rocket be ferried back to Sea Launch's Home Port in Long Beach, California.

The Sea Launch vessels are due to begin the 3,000-mile journey from their position on the equator to Long Beach later this week. Once in the processing facility, technicians will re-start of the 50-day launch campaign.

With this extended delay for the XM 1 spacecraft, officials say the ripple effect will push back the launch of XM 2 to mid-April aboard another Zenit 3SL rocket. It has been slated for March. However, XM Satellite Radio says it will still be able to roll out its commercial service this summer as planned.

MONDAY, JANUARY 8, 2001

Activities are underway aboard the Odyssey launch platform to drain the fuel from the Zenit 3SL, finish safing the vehicle and prepare for another attempt.

The countdown was stopped at T-minus 11 seconds after the launch team noted a problem with the XM 1 satellite payload. Specific information about the problem has not been confirmed by officials, but it appears to be a minor out-of-specification condition on an internal system.

As the launch team identified the concern, officials frantically ordered the countdown stopped with less than 30 seconds until blastoff. The water deluge system did activate, sending a torrent of seawater into the flame trench of the Odyssey launch platform. The commentator mistakenly called engine ignition and liftoff despite the already-halted countdown. Watch a video clip of the dramatic moments.

Although the issue was quickly resolved, the rocket could not been prepped in time for another countdown within today's available launch window.

It is expected to be Friday before the launch is attempted again.

Built by Boeing Satellite Systems, the XM 1 spacecraft (nicknamed "Roll") will be boosted into geosynchronous transfer orbit by the three-stage Zenit. From there the satellite will maneuver itself into geostationary orbit 22,300 miles above the equator with a view of the United States. XM 1 is to be joined by sister-satellite XM 2 (nicknamed "Rock") in March.

Together the spacecraft will beam 100 channels of digital radio programming, including music, news, sports and entertainment, to subscribers of the XM Satellite Radio service. Customers across the U.S. will need a special receiver in their cars or home to pick up the satellites' signal. The service, to debut commercially this summer, will cost $9.95 per month.

"XM will give the world a glimpse of the future of radio," said Hugh Panero, XM's president and CEO. "We're confident retailers and consumers alike will agree that XM is changing radio the way cable changed TV."

XM has signed programming agreements with content providers, including USA TODAY, NASCAR, Sesame Workshop, the Country Music Hall of Fame, the BBC World Service, Black Entertainment Television, Hispanic Broadcasting Corporation, Bloomberg, C-SPAN Radio, CNNfn and CNN/Sports Illustrated.

2241 GMT (5:41 p.m. EST)

Sea Launch has concluded its broadcast on today's mission following the postponement. Details on what caused the countdown abort at T-minus 11 seconds are not yet known. We will provide additional details tonight as soon as they become available.

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

It appears the countdown was stopped at T-minus 11 seconds due to a technical problem. The transporter/erector arm is going to be rolled back out of its hangar and reconnected to the rocket. It is now expected to be four to five days before the launch could be tried again.

2237 GMT (5:37 p.m. EST)

The launch team continues safing the Zenit 3SL rocket following the countdown cutoff tonight in the final seconds.

2235:30 GMT (5:35:30 p.m. EST)

Again, the countdown was halted in the final seconds due to some sort of problem. No word on what the situation was that the caused the halt.

Meanwhile, Arianespace has scrubbed tonight's Ariane 4 launch at virtually the same moment as the Sea Launch abort.

2235 GMT (5:35 p.m. EST)

ABORT! Countdown clocks have stopped!

2234:30 GMT (5:34:30 p.m. EST)

T-minus 1 minute. Now 60 seconds away from liftoff.

2233:30 GMT (5:33:30 p.m. EST)

T-minus 2 minutes. The engine start preparations are beginning.

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

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

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

T-minus 4 minutes and counting. The transporter/erector arm is now fully retracted to the hangar and the doors have been sealed. Also, XM 1 is on internal power.

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

T-minus 5 minutes and counting. Standing by for final readiness polls.

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

T-minus 8 minutes and counting. The countdown continues with no problems reported.

2225 GMT (5:25 p.m. EST)

T-minus 10 minutes and counting. The weather conditions at the launch site along the equator are beautiful and well within limits for liftoff just 10 minutes from now.

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

T-minus 12 minutes and counting. The final launch danger area sweep by the Sea Launch helicopter has been completed with the zone verified clear.

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

T-minus 14 minutes and counting. The automated launch sequence continues smoothly. At this time launch team members are verifying healthy telemetry links and confirming the guidance computer updates to the rocket's Block DM-SL upper stage.

2220 GMT (5:20 p.m. EST)

T-minus 15 minutes and counting. The transporter/erector arm is in motion. Also, the XM 1 "Roll" spacecraft is switching to internal power for launch.

2218 GMT (5:18 p.m. EST)

T-minus 17 minutes and counting. The countdown is reaching a major milestone as the transporter/erector arm is retracted from against the rocket. The arm was used earlier to roll the rocket out of the environmentally-controlled 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.

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

As the Arianespace launch is on hold, Sea Launch is counting down the final 20 minutes to its flight of the Zenit 3SL rocket carrying the first spacecraft for XM Satellite Radio. Sea Launch officials aboard the command and control ship located at 154 degrees West longitude on the equator report all systems are go for liftoff at 2235:30 GMT.

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

Fueling operations are commencing aboard the Odyssey platform stationed on the equator in the Pacific Ocean, about 1,400 miles southeast of Hawaii, for today's launch of the Zenit 3SL rocket. The vehicle is being loaded with kerosene propellant and cryogenic liquid oxygen. The platform has been cleared off all workers for this hazardous operation, with all personnel now aboard the Sea Launch Commander ship safely positioned about 3.5 miles away.

1915 GMT (2:15 p.m. EST)

The final hours of the countdown are underway as Sea Launch technicians ready the Zenit 3SL rocket for flight later today carrying the XM Satellite Radio "Roll" spacecraft. Sea Launch is not reporting any significant troubles and the weather forecast is favorable for the liftoff at precisely 2235:30 GMT (5:35:30 p.m. EST).

SUNDAY, JANUARY 7, 2001

The three-stage Ukrainian-Russian Zenit 3SL rocket was rolled from its hangar and erected atop the Odyssey launch platform today. The final day of the 72-hour countdown is underway as Sea Launch prepares for Monday's scheduled 2235:30 GMT (5:35:30 p.m. EST) blastoff on a 65-minute mission to deliver the first XM Satellite Radio broadcasting spacecraft into geosynchronous transfer orbit.

In the final few hours of the countdown Monday, the rocket's stages will be loaded with kerosene fuel and super-cold liquid oxygen. The Sea Launch Commander -- which serves as the floating control center -- will be positioned about 3.5 miles from Odyssey where the 300-member launch team can oversee the activities to ready the rocket for liftoff.

Nicknamed "Roll", this first of two XM satellites will be used to beam 100 channels of music, news and entertainment programming directly to automobiles and special radios of subscribers across the United States starting later this year. The service will cost $9.95 per month, and is a direct competitor to Sirius Satellite Radio. Sirius has already launched its three satellites and its preparing to debut commercial service.

We will have much more on XM Satellite Radio and its plans during our live reports during the final countdown and launch on Monday. Watch this page beginning about a half-hour prior to launch time.

FRIDAY, JANUARY 5, 2001

The Sea Launch vessels arrived at the equator on Friday, completing a 3,000-mile journey from their home port to the designated spot in the Pacific where a Zenit 3SL booster will blast skyward Monday carrying the first digital broadcasting spacecraft for XM Satellite Radio.

Immediately after arriving at the launch site, the Odyssey launch platform filled its ballast tanks with seawater to place the Odyssey at its launch depth. The Sea Launch Commander then pulled alongside the Odyssey to help the launch platform crew make final preparations on the platform and the Zenit 3SL rocket.

During the trip from the Sea Launch Home Port in Long Beach to the Pacific Ocean launch site, Sea Launch launch controllers conducted two different launch rehearsals, one on December 30 and one on January 3.

The Sea Launch Commander and the Odyssey launch platform rendezvoused together early on January 2, then continued the journey to the launch site together. They departed Long Beach three days apart.

The 72-hour long launch countdown commenced this afternoon. Final checks on the rocket, the XM-1 satellite payload, the launch platform, and the systems on the Sea Launch Commander will dominate the schedule this weekend. Also on tap will be the raising of the Zenit 3SL rocket to the vertical position on the Odyssey's launch pad during the final day of the countdown.

Stay with Spaceflight Now for complete coverage of Monday's launch.

MONDAY, JANUARY 1, 2001

The Sea Launch command ship and Odyssey platform are sailing to the equatorial waters of the Pacific Ocean for next week's flight of a Zenit 3SL rocket with the first of two broadcasting spacecraft for XM Satellite Radio.

Liftoff is targeted for 2235 GMT (5:35 p.m. EST). The available launch window extends for 37.5 minutes.

The blastoff will occur from atop the Odyssey launch platform -- a modified Norwegian oil drilling platform -- located at the junction of the 154th meridian West longitude and the equator. This type of location is prime real estate for the space launch industry because it can take full advantage of the Earth's rotation to help boost the launch vehicle into a geostationary transfer orbit. Also, because of the desolate location of such a place, the rocket could launch in almost any direction and still not over-fly any populated regions.

Satellite pre-launch processing for Sea Launch's sixth mission began on December 2 when the spacecraft arrived at the Sea Launch Home Port in Long Beach, California, from the Boeing Satellite Systems facility located just a few miles away in El Segundo, California. XM 1 -- nicknamed "Roll" -- was transferred to the Payload Processing Facility, where it underwent final tests and check-outs of its systems and was fueled.

Later inside the Payload Processing Facility (PPF), the satellite was put through a process called encapsulation. The spacecraft was mated to its payload adapter, then the protective payload fairing was placed around the payload adapter and spacecraft in two halves.

On December 17, the completed payload unit was rolled out from the PPF to the Assembly and Command Ship (ACS), named the Sea Launch Commander. There, the unit was attached to the Zenit's Block DM-SL upper stage, where it will stay until just over an hour after launch.

The completed Zenit 3SL launch vehicle, payload included, was transported from the Sea LaunchCommander to the Odyssey launch platform on December 21. During the journey to the equator in the Pacific Ocean, the rocket is positioned horizontally inside a hangar-like structure on the Odyssey launch platform. If all goes well, it is only outside the hangar and in a vertical position twice.

The first trip outside the hangar took place on December 22, while still in the Home Port of Long Beach. This time, the excursion was only a test, and the rocket was quickly put back in its cocoon-like hangar.

On Christmas morning, the Odyssey left Long Beach bound for the far-away Central Pacific Ocean. The trip is expected to take around two weeks to complete for the launch platform.

Two days later, on December 28, the Sea Launch Commander departed the Sea Launch Home Port en route to the equatorial launch site. The Sea Launch Commander leaves a few days after the Odyssey because it can attain higher speeds than the launch platform.

The two vessels were on track to rendezvous in the Pacific Ocean on New Year's Day.

After joining up, the pair will conduct a series of launch rehearsals and drills, priming the equipment, hardware, and workers for the wear-and-tear of the 72-hour launch countdown.

In the days leading up to launch, Sea Launch workers will start the 3-day launch countdown and roll out the Zenit 3SL rocket from the launch platform's hangar to Odyssey's launch pad where it will be erected into a vertical position. All of this will occur as the ships arrives at the equator.

Sea Launch mission six will deliver the XM 1 satellite into geostationary transfer orbit in just over an hour. Once in the transfer orbit, it will use its on-board propulsion system to place itself in a final geostationary orbit 22,300 miles high above a point along the equator at 85 degrees West, or over the Pacific Ocean west of Ecuador.

The Boeing 702 satellite will weigh 9,810 pounds when fully fueled at launch. Once in orbit, it will feature a mass of 6,505 pounds during its scheduled 15 years of operations. The craft's twin solar arrays will measure 132.5 feet tip-to-tip when fully deployed in space.

"Roll" will be joined in space by the XM-2 spacecraft, nicknamed "Rock" within the next two months. Together, they will broadcast 100 channels of digital audio content, including news, information and music.

It will be Sea Launch's first mission of the new year. 2000 was filled with ups and downs for the international consortium. The third flight of the Zenit 3SL last March ended in failure when the second stage of the rocket shut down prematurely. Two later flights were successful.

Stay with Spaceflight Now for continuing updates on pre-flight preparations and live coverage of the launch on January 8. We will provide live play-by-play updates during the final countdown and mission.