NASA - National Aeronautics and Space Administration

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2:22 p.m. - Deep Impact has successfully separated from the
Delta II's third stage and is on its way to Comet Tempel 1. Cheers erupt from the NASA Launch Team.

2:21 p.m. - Yo-yo despin has occurred.

Did You Know?
A yo-yo despin system is designed to slow down the spin rate of the third stage to a very slow rate just prior to spacecraft separation from the motor. The system is comprised of two weights that are released from the motor but stay tethered to it. The small mass of these weights causes the spinning third stage to gradually stop spinning. This is a spacecraft requirement. The Deep Impact project wants the spacecraft to separate from the third stage with very little spin to it for control purposes.

2:16 p.m. - The third-stage engine has completed its burn.

2:15 p.m. - Second stage separation and third-stage engine ignition have been confirmed.

2:14 p.m. - Second-stage engine shutdown has been confirmed.

2:11 p.m. - The Delta II has reignited its second-stage engine and will burn it for approximately one minute and thirty-five seconds.

2:00 p.m. - The Delta II rocket has achieved its "parking" orbit. A parking orbit is where the rocket enters a coast phase (a circular orbit) before restarting its second-stage engine.

Did You Know?
The rocket is actually launched by the click of a computer mouse.

1:56 p.m. - We now have confirmed cutoff of the second-stage engine (SECO).

1:52 p.m. - The protective fairing has separated from the Delta II.

1:51 p.m. - We have Main Engine Cutoff (MECO).

1:50 p.m. - The three air-start boosters have now been jettisoned.

1:48 p.m. - Our official launch time today was 1:47:08.574 p.m. EST.

1:48 p.m. - At T+48 seconds, all six solid rocket motors have been jettisoned.

1:47 p.m. - At T+36 seconds, the Delta II rocket is supersonic.

1:47 p.m. - T-10....9...8...7...6...5...4...3...2...1... We have ignition and liftoff of a Delta II rocket carrying Deep Impact -- NASA's journey to unlock the mystery of the solar system's origin.

1:46 p.m. - T-45 seconds and counting.

1:45 p.m. - We are at T-2 minutes and counting. The Team is cleared for launch!

1:43 p.m. - We are at T-4 minutes and counting.

1:42 p.m. - The NLM has conducted a final launch readiness poll to come out of the T-4, 10-minute built-in hold and continue with the terminal countdown. The NASA Team is Go.

1:41 p.m. - The Launch Conductor has just briefed the team with final instructions for launch.

1:33 p.m. - We are at T-4 minutes and holding. This is a 10-minute built-in hold.

1:30 p.m. - T-7 minutes and counting.

Did You Know?
It will take Deep Impact about six months to reach Comet Tempel 1.

1:27 p.m. - The NASA Launch Manager (NLM) reports that the range is "green" and there are no constraints for launch at this time.

1:17 p.m. - The 20-minute hold has been released and we are at T-20 minutes and counting.

1:09 p.m. - The NASA Launch Manager has said that the range is "red" due to high level winds from 52,000 to 65,000 feet. He is polling the team at T-20 minutes and holding to come out of the built-in hold. The NASA Team has indicated that they are ready to continue with the countdown.

Did You Know?
Deep Impact's flyby spacecraft literally drops off the impactor in a position to be hit by the comet.

12:57 p.m. - At T-20 minutes we have now entered a planned 20-minute hold.

12:54 p.m. - The slew checks are now complete for both stages.

12:47 p.m. - We are at T-30 minutes and counting. The "slew checks" are now in process to test the movement of the Delta II's rocket nozzles. The second stage will be checked first, followed by the first stage.

12:30 p.m. - At 12:30:22 p.m. loading of LOX was completed and took a total of 26 minutes and 42 seconds.

12:30 p.m. - T-47 minutes and counting.

12:28 p.m. - We are now 95% complete with LOX loading. The rapid load has closed and the fine load has opened to continue to 100%.

Did You Know?
Deep Impact will produce a crater on the surface of Comet Tempel 1 that could range in size from a two-bedroom house to the Roman Coliseum.

12:23 p.m. - We are now 20 minutes into the loading of LOX. The entire process takes 25 minutes to complete.

12:14 p.m. - We are now at 11 minutes into the flow of LOX. From a vent on the rocket's side, a normal bright white vapor can be seen puffing out as the loading continues. The rocket's exterior is now covered in frost, turning the normally green paint scheme to a snowy white color.

12:11 p.m. - We are now eight minutes into the loading of LOX.

12:03 p.m. - At T-75 minutes and counting, liquid oxygen (LOX) loading into the Delta II rocket is underway.

Did You Know?
The Deep Impact flight system is actually two spacecraft mated together. One part, the impactor, will fly into the nucleus of Comet Tempel 1. The second part, a flyby spacecraft, acts as the mothership of the combo, carrying and powering the impactor until 24 hours before the comet impact. Each of these two spacecraft has its own instruments and capabilities to receive and transmit data.

11:57 a.m. - At T-80 minutes and counting, the blast area is clear. The temperature at lift off should be 76 - 78 degrees Fahrenheit.

11:51 a.m. - The NASA Launch Manager has conducted the poll for cryo tanking and the Launch Team is "go" and ready to proceed.

11:41 a.m. - At T-95 minutes, an updated weather briefing was given. The current forecast calls for a 10% chance of weather violation. If today's launch is postponed until tomorrow, the chances of weather violation increase to 30%.

11:31 a.m. - RP-1 fuel loading is complete and took 19 minutes and 30 seconds.

11:29 a.m. - Rapid loading has been closed for the RP-1. Fine loading will progress until we reach 10,024 gallons or 100%.

11:28 a.m. - 10,024 gallons of fuel will be the flight load of RP-1 for launch, however we will stop loading at 9,840 gallons or 99% loaded and fill the remainder towards the end of the countdown.

11:22 a.m. - 6,000 gallons of RP-1 are now loaded into the rocket's first stage.

11:15 a.m. - We are now four minutes into the flow with over 2,000 gallons loaded.

11:13 a.m. - 1,000 gallons of fuel have been loaded at this time.

11:12 a.m. - The RP-1 loading has begun. There will be approximately 9900 gallons loaded.

11:07 a.m. - Initial preparations for the loading of RP-1 kerosene fuel have begun for the Delta II rocket's first stage.

10:47 a.m. - The Complex 17B launch area has been cleared of all personnel. A warning horn was sounded to alert anyone in the vicinity to leave the area immediately. This action will allow for the beginning of fuel loading.

10:47 a.m. - The built-in hold has been released and we are at T-150 minutes and counting.

10:38 a.m. - The NASA Launch Manager (NLM) has conducted a poll and we will release from the T-150 minute hold shortly.