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MESSENGER Launch Day Events
The Virtual Launch Control Center was activated at 12:00 a.m. EDT

The Virtual Launch Control Center was deactivated at 3:15 a.m. EDT. Thank you for joining our live coverage of the successful launch of MESSENGER.

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3:12 a.m. - Spacecraft separation is achieved! Cheers have erupted in Launch Control as MESSENGER sets out on its own.

3:11 a.m. - The USN Station in Dongara, Australia is now tracking the data coming in from the spacecraft.

3:07 a.m. - Third stage burnout; gyro data is good.

3:06 a.m. - Successful ignition of the third stage. Data is now being tracked by the PERL Station USAF Deployable telemetry station in Exmouth Australia.

3:05 a.m. - Second stage shutdown! We have spin-up. The spacecraft is orbiting about a mile high.

Did you know?
MESSENGER will travel 22.7 million miles a year while in orbit around Mercury.

3:03 a.m. - One minute into the burn, data from the OTTR station is very good.

3:02 a.m. - We have ignition of the second stage's second burn. This burn will last just under three minutes.

3:01 a.m. - We've received confirmation of the acquisition of the spacecraft's signal from the OTTR station in the Indian Ocean.

2:51 a.m. - MESSENGER is passing the Eastern tip of Africa.

2:42 a.m. - We've seen the scheduled loss of signal from Ascension Island as the Delta 2 goes over the horizon. Telemetry should be reacquired in about 19.5 minutes by the OTTR (U.S. Air Force Deployable Telemetry shipboard station).

2:39 a.m. - At 23 minutes into flight, the second stage coast data is showing that everything is normal. Two and a half minutes of Ascension Island data remain.

Did you know?
MESSENGER is carrying seven scientific instruments to answer six important questions about Mercury.

2:35 a.m. - At 19 minutes into MESSENGER's flight, the Ascension Island Tracking Station has acquired the spacecraft's signal.

2:26 a.m. - We're now 10 minutes 52 seconds into the fight.

2:24 a.m. - Second stage cutoff! Hydraulic pumps have switched off on command. We're now entering a coast phase that will last about 37 minutes.

2:21 a.m. - The vehicle is 77.5 nautical miles in altitude at a llittle over five minutes into flight.

2:20 a.m. - Main engine cutoff; the first and second stages have separated and the stage 2 engine has ignited.

2:18 a.m. - The official launch time was 2:15:56.537 a.m. EDT.

2:18 a.m. - The three air-lit solids have been jettisoned. The vehicle is already 215 nautical miles away.

2:15 a.m. - 10, 9, 8, 7, 6, 5, 4, 3, 2, 1... and liftoff of MESSENGER on NASA's mission to Mercury, a planetary enigma in our inner solar system!

2:15 a.m. - T-30 seconds -- the LOX fill and drain valve is closed. Range is go for launch.

2:12 a.m. - T-3 minutes and counting.

2:11 a.m. - T-4 minutes and counting. Spacecraft is green.

2:10 a.m. - T-6 minutes. Spacecraft is being configured for launch and is on internal power.

2:09 a.m. - The launch team members have been given their final countdown instructions. They were advised that if there any alarms after the T-4 hold, a hold will be called. There are no allowable alarms after T-60 seconds.

2:07 a.m. - The Launch Conductor's poll is underway. The team is ready; we are good to go.

2:05 a.m. - The NASA Launch Manager has polled the NASA team and they report that they are ready to proceed with the launch.

2:04 a.m. - The LOX fill and drain valve continues to be cycled on and off to prevent it from getting sluggish in the final minutes before launch.

2:01 a.m. - T-4 minutes and holding for 10 minutes.

2:00 a.m. - The LOX level will now be topped off to 100% and maintained between 99% and 100% until launch. Facility water tanks are being pressurized. The Launch Weather Officer reports that weather is go.

1:59 a.m. - T-7 minutes and counting. Three minutes remain until the T-4 minute built-in hold.

1:57 a.m. - The vehicle's LOX tank is being cycled on and off. The cycling causes the appearance of smoke puffing out of the rocket.

1:56 a.m. - T-10 minutes and counting. There are six minutes remaining until the final built-in hold at T-4 minutes. Upper level wind data continues to be acceptable.

1:54 a.m. - T-12 minutes and counting. Range safety command checks are completed and acceptable.

1:46 a.m. - T-20 minutes and counting. The next planned hold is at T-4 minutes, which will be a 10 minute hold.

1:41 a.m. - The Mission Director's poll is underway. The team is ready to resume the countdown. We are five minutes away from the end of the hold.

1:38 a.m. - The NASA Launch Manager (NLM) is conducting his final launch poll for readiness to proceed with the countdown. We're approaching the end of the T-20 minute hold. The launch vehicle and spacecraft are healthy, and there are no weather issues in work. Upper level winds are green.

Did you know?
MESSENGER is mainly powered by two solar panels and the energy is stored in a nickel-hydrogen battery.

1:27 a.m. - Clouds are thin and transparent, and anvil clouds are not a concern at this time but will continue to be monitored. We are green on all constraints.

1:25 a.m. - The countdown has entered the T-20 minute built in hold, which will last 20 minutes. A weather briefing will occur during this hold.

1:23 a.m. - Engine slews are completed.

1:17 a.m. - The launch vehicle's engines are undergoing steering checks, known as slews. The second stage will be checked first, followed by the first stage.

1:08 a.m. - LOX loading is complete. Coming up are engine slews and range safety beacon checks. Weather is still go.

1:06 a.m. - Operation of the fill and drain valve is reported to be acceptable.

Did you know?
Once the LOX is 100% loaded, the rapid load valve is cycled a minimum of three times for testing before it is closed for launch. The rapid load valve is closed for flight at T- 30 seconds.

1:03 a.m. - The LOX fill and drain valve has been cycled twice and is currently in the open position.

Did you know?
Mercury's atmosphere is a trillionth the density of Earth's atmosphere and composed chiefly of argon, neon and helium.

12:52 a.m. - At T-53 minutes and counting, we are currently 18 minutes into the fueling of liquid oxygen (LOX) in the first stage of the Delta II rocket. As the rocket is fueled with LOX, gaseous oxygen (GOX) is released, which is visible as it vents from the rocket.

12:45 a.m. - We are 11.5 minutes into the flow of liquid oxygen. It will take about 25 minutes to completely fill the tank.

12:41 a.m. - We are green all the way across the board on all constraints. At this point, there are no issues in work with the spacecraft, the launch vehicle or weather. We are still waiting on upper-level wind data.

12:39 a.m. - We are five minutes into first stage cryo tanking of the Delta rocket.

12:32 a.m. - Cryogenic tanking has begun. Super-cold liquid oxygen (LOX) has started flowing into the Delta II rocket's first stage.

Did you know?
The gravity assist MESSENGER receives from its flybys of other planets reduces the amount of fuel needed onboard the spacecraft.

12:19 a.m. - The NASA Launch Manager reports that with the exception of weather, there are no issues in work this morning. There are no problems with the spacecraft or launch vehicle. The entire launch team has been polled and is go to begin cryogenic tanking.

12:13 a.m. - The T-95 weather briefing just concluded. Although earlier thunderstorms are dissipating, we are currently red on weather due to anvil clouds and thick clouds. There is a chance that the remnant cloud cover will continue to thin, leading to more favorable weather.

The following countdown events took place before the start of today's MESSENGER launch coverage:

11:55 p.m. - The first stage has been filled to 98% with RP-1 fuel. It will be topped off to a full load of 9,750 gallons during the "fine load" process.

11:41 p.m. - Nearly 10,000 gallons of rocket propellant 1 (RP-1) fuel -- a highly refined kerosene propellant -- are now being loaded into the first stage of the Delta II launch vehicle. This is called the "rapid load."

11:19 p.m. - Pressurization of helium and nitrogen storage tanks of the Delta rocket's first and second stages has begun.

11:16 p.m. - We are now at T-150 and counting. The horn has been sounded at the pad and the warning beacon has been activated. We are now in the terminal countdown leading up to the launch of MESSENGER at 2:15 a.m.

11:07 p.m. - Launch Conductor conducts a terminal countdown briefing. During this briefing he gives the current status of the pad and gives an updated weather briefing. At this time there is a red condition for weather.

10:58 p.m. - NASA Launch Manager reports that the spacecraft and launch vehicle are green for launch. At this time weather is still red. The poll on the readiness to proceed with the terminal count at the end of the T-150 60 minute built in hold was conducted and all team members are ready to proceed.

10:50 p.m. - The launch complex has been cleared of all personnel in readiness of the terminal phase of the countdown.

Did you know?
MESSENGER's highly elliptical orbit will bring the spacecraft as close as 125 miles from the planet's surface, and as far away as 9,400 miles.