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 2:50 a.m. EDT. Please continue to visit the Virtual Launch Control Center for the latest status of the MESSENGER launch.

All times are in EDT unless otherwise stated.

2:15 a.m. - Similar weather is predicted tomorrow. However, if Tropical Storm Alex moves farther away, the forecast would likely improve.

2:09 a.m. - The team will attempt a 24-hour turnaround with a launch planned for Tuesday, August 3, at 2:15:56 a.m.

2:09 a.m. - Tonight's launch is scrubbed due to weather constraints. Stand by for further information...

Did you know?
Johann Hieronymus Schroeter (1745-1816) was the first to observe Mercury and record detailed drawings of the planet's surface features.

2:02 a.m. - T-4 minutes and holding. This is a 10 minute built-in hold. The Launch Weather Officer has reported that as of now, we are no go for launch due to weather. Further evaluation will continue during this hold.

2:01 a.m. - T-5 minutes and counting. We're coming up on the T-4 minute hold.

1:57 a.m. - Beacon is on internal power.

1:56 a.m. - Bad news from the weather aircraft: The clouds, which the team had hoped would be transparent, appear to be thick clouds -- a weather constraint. All other weather, as well as the spacecraft and vehicle, are green for launch. The countdown will continue as far as possible while weather is monitored closely.

1:50 a.m. - T-15 minutes and counting.

1:46 a.m. - The countdown has resumed - we are now out of the T-20 built in hold. Only one hold remains, a ten minute hold at T-4 minutes.

Did you know?
MESSENGER's sunshade allows the spacecraft electronics to operate at room temperature even in the hot Mercury environment.

1:42 a.m. - The Boeing Launch Director is now conducting his poll to continue. All team members have given a go for continuing the countdown for the MESSENGER launch.

1:38 a.m. - The NASA Launch Manager (NLM) has completed his poll on readiness to proceed with the count as we come out of the 20 minute hold.

Did you know?
MESSENGER's sunshade allows the spacecraft electronics to operate at room temperature even in the hot Mercury environment.

1:32 a.m. - As the countdown proceeds, steam can be seen periodically "puffing" due to the liquid oxygen valve being cycled on and off.

1:30 a.m. - No technical issues are in work at this time; the spacecraft and vehicle are go. However, we are still red on anvil clouds.

1:26 a.m. - The T-20 minute hold has begun. Thus far, the countdown has proceeded without incident, and we are right on schedule. Another weather update is expected shortly.

1:23 a.m. - First stage slews are complete.

1:19 a.m. - Second stage slews are complete.

1:16 a.m. - T-30 minutes and counting. Since LOX loading was completed on schedule, the engine steering checks, known as slews, are underway. The second stage will be checked first, followed by the first stage.

1:13 a.m. - At T-33 minutes and counting, the launch team is preparing to perform engine slew checks.

Did you know?
Mercury completes a trip around the Sun every 88 days, speeding through space at about 31 miles per second, faster than any other planet.

1:00 a.m. - After 27 minutes, LOX loading has concluded. The Delta II is now fueled to 95%, where it will remain until it is topped off shortly before launch.

12:59 a.m. - T-47 minutes and counting. NASA Assistant Launch Manager Omar Baez reports that if the anvil clouds are transparent, they won't pose a problem for launch. But if the clouds are thick, this could become a launch issue.

12:49 a.m. - Now 16 minutes into the loading of the super-cold LOX, the vehicle appears to turn white as ice forms on the outside.

12:43 a.m. - We are now 10 minutes into cryo loading.

12:33 a.m. - The Delta II Heavy's first stage is being filled with super-cold liquid oxygen (LOX).

12:30 a.m. - We are at T-75 minutes and counting.

12:24 a.m. - We are currently red on cloud constraints due to anvil clouds and Tropical Storm Alex. Another weather check is expected between 12:30 and 12:45 a.m.

12:20 a.m. - The NASA Launch Manager has conducted his poll, and we are ready for cryo tanking.

12:12 a.m. - The T-96 minute weather briefing has concluded. There is a 30% chance of weather violation, due mostly to clouds. Right now, however, we are green on all weather constraints.

12:00 a.m. - RP-1 loading was completed after 18 minutes and 41 seconds for a total of 9,949 gallons.

11:48 p.m. - We are 7 minutes and approximately 4,500 gallons into the
RP-1 fueling.

11:41 p.m. - The spacecraft is being fueled with RP-1 in preparation for launch. RP-1 is a highly refined kerosene propellant. Approximately 10,000 gallons will be loaded into the Delta 2 rocket's first stage.

Did you know?
MESSENGER's 12-month orbit covers two Mercury solar days which is equal to 176 Earth days.

Launch Countdown Concluded
Join us for tomorrow's coverage of the launch of MESSENGER, Mission to Mercury.
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Tomorrow's Forecast
Mission Control team discusses weather possibilities for next launch window.
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Standing Down
MESSENGER's launch has been postponed because of weather constraints.
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Weather at the Pad
Tower at Pad 17-B was rolled back in preparation for launch.
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MESSENGER's Technology
Dr. Ralph McNutt, MESSENGER Project Scientist describes the science and technology of the spacecraft.
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Readiness Review
George Diller and Assistant Launch Director Omar Baez discuss spacecraft readiness.
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MESSENGER: Made to Order
Ted Hartka, Lead Mechanical Systems Engineer, explains the processing of MESSENGER.
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MESSENGER's Tanks
are Filled
Cryotanking has been approved and MESSENGER is fueled and ready to go!
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Weather Report
Delta Weather Officer Joel Tumbiolo reviews weather constraints for launch window.
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Voyage to Mercury Begins
NASA Launch Commentator George Diller describes MESSENGER mission and spacecraft readiness.
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