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Mission: STS-121/ULF1.1
Orbiter: Discovery

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NASA's Launch Blog - Mission STS-121


The NASA Launch Blog was activated at 10:00 a.m. EDT.

The NASA Launch Blog was deactivated at 3:46 p.m. EDT.

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Post-Coverage Interview: Launch Commentator Bruce Buckingham talks to Launch Manager Mike Leinbach about the weather that scrubbed NASA's first attempt to launch Space Shuttle Discovery on mission STS-121.
+ View Leinbach Interview

3:42 p.m. - The first attempt to launch Space Shuttle Discovery on mission STS-121 was scrubbed due to weather constraints. The launch team made the decision to delay the launch by 24 hours.
+ View Scrub Announcement

3:42 p.m. - Scrub! Mike Leinbach, NASA Launch Director, has decided that today is not a good day to launch the shuttle and we'll try again tomorrow. The primary concern was for anvil clouds within 20 miles of the Shuttle Landing Facility. Our preferred launch time for tomorrow is 3:26 p.m. from Kennedy Space Center.

3:39 p.m. - The T-9 minute hold has been extended for resolution of weather and range constraints.

3:34 p.m. - Launch Director Mike Leinbach has completed his final poll for launch. The team is go with the exception of Houston Flight and Range Weather which are still no-go based on the anvil rule. Mike Leinbach says we will use up the launch window and remain in the T-9 minute hold and use the extra five minutes on the chance the weather will clear for launch.

3:27 p.m. - Weather is still no-go for launch. Part of the concern is for overcast conditions above the abort landing site at Kennedy.

3:20 p.m. - Based on the weather briefing he received, Launch Director Mike Leinbach says "it's going to be close but we're going to give it a shot," as the team presses on for launch.

3:16 p.m. - At T-9 minutes and holding, we are still "no-go" for thunderstorms and clouds in the area. The Shuttle Launch Weather Officer is still monitoring the situation and the weather does still have time to clear. There will be a number of polls coming up: one by John Shannon of the Mission Management Team, one by Jeff Spaulding for the Test Directors and Mike Leinbach will conduct one as Launch Director. All of these polls determine if we are ready to come out of the hold.

Did you know?
The weather conditions must be acceptable at one of the three Transatlantic Abort Landing (TAL) sites to launch. The sites are Zaragoza, Spain; Moron, Spain; or Istres, France. Today's preferred landing site is in Moron, Spain.

2:54 p.m. - The countdown is at T-9 minutes and holding. The Closeout Crew is departing the pad.

2:50 p.m. - Pilot Mark Kelly is configuring computer displays in the cockpit for launch. NASA's Contingency Support Operations are reporting ready. There is one scheduled hold remaining in the countdown at T-9 minutes; it is a 40-minute built-in hold.

2:43 p.m. - The march to launch continues with T-20 minutes and counting. The orbiter's thruster issue has been cleared for launch by the Mission Management Team. The weather is still in question, but there are no other major issues being addressed. Calibrations of Discovery's navigation system IMUs have been completed.

2:38 p.m. - NASA Test Director Jeff Spaulding has given the T-20 briefing to update the launch team on how to handle any issues that could arise during the rest of the hold.

Did you know?
The Hubble Space Telescope was launched aboard Shuttle Discovery on STS-21 in April 1990.

2:33 p.m. - The countdown is at T-20 minutes and holding. This is a programmed, built-in hold lasting for 10 minutes.

2:14 p.m. - The Ground Launch Sequencer (GLS) mainline activation has been completed. The GLS is a master computer program which controls the final nine minutes of the countdown. The GLS will monitor approximately one thousand different measurements to ensure the system operates within predetermined limits.

2:02 p.m. - T-49 minutes and counting. The Closeout Crew is completing the steps for hatch closure, locking and sealing. Preflight checks of the inertial measurement units (IMU) are in progress and expected to be completed during the T-20 minute hold. The three IMUs are used by Discovery's navigation system to determine the ship's position during flight. Weather is still an issue because of anvil clouds over Kennedy Space Center.

Did you know?
Three of the astronauts on STS-121 are taking their first flight. + Read More

1:46 p.m. - The STS-121 crew members, now strapped into their seats inside Discovery, are conducting air-to-ground communications checks with Launch and Mission Control.

Did you know?
Thomas Reiter is the first ESA long-duration space station crew member and will remain on board the ISS for six to seven months to work with the Expedition 13 and 14 crews.

1:08 p.m. - Mission Specialist Lisa Nowak is now getting ready to enter the orbiter. She will be sitting on the flight deck between Steve Lindsey and Mark Kelly. Nowak will be the last crew member to enter the orbiter before the hatch is closed.

1:04 p.m. - NASA's two solid rocket booster recovery ships, the Freedom Star and Liberty Star, are on-station in the Atlantic Ocean about 140 miles northeast of the Kennedy Space Center, off of the coast of Jacksonville, Fla. The ships are deployed two days prior to launch, which in this case was on Thursday.

The ships will retrieve the boosters, return them to the Cape, where they will later be sent by train to Utah to be refurbished for a future shuttle launch.

Did you know?
There are thermal blankets and over 25,000 tiles which protect the aluminum structure of Discovery. + View Video

1:00 p.m. - Pilot Mark Kelly is performing initial air-to-ground communications checks with Launch and Mission Control in Houston, while the rest of the crew members are getting into the vehicle and making final preparations for flight.

12:50 p.m. - There is lightning in the area of Launch Pad 39B, however, the crew members are still entering the orbiter and preparing to fly this afternoon.

12:41 p.m. - Astronaut Mike Bloomfield will be piloting the Shuttle Training Aircraft (STA) today to assess the flying weather during the launch countdown. He will be taking off shortly from Kennedy's Shuttle Landing Facility to give a pilot's perspective on current weather conditions.

12:39 p.m. - Piers Sellers and Mike Fossum are getting ready to enter the orbiter. An updated weather briefing puts us back in "the red" for weather due to clouds, but there is still plenty of time in the countdown for the skies to clear.

12:36 p.m. - Mission specialist and first time astronaut Stephanie Wilson is the next astronaut to enter the orbiter.

12:33 p.m. - In the white room at Launch Pad 39B, the closeout crew assists the astronauts as they, one by one, enter Discovery and are strapped in for launch.
+ View White Room Activities

12:31 p.m. - European Space Agency (ESA) astronaut Thomas Reiter is the next crew member to be seated in Discovery. Reiter will be sitting below the flight deck in the mid-deck area. Pilot Mark Kelly follows Reiter and will be seated on the flight deck next to Commander Lindsey.

Did you know?
This will be the fourth trip to the ISS for the Multi-purpose Logistics Module Leonardo. + Read More

12:22 p.m. - The Astronaut Support Personnel known as the "Cape Crusaders," helped prepare the orbiter for launch today. The team supporting today's launch is led by astronaut Douglas (Chunky) Hurley as the Prime for this mission with Michael (Bueno) Good as back-up Prime and Alan (Dex) Poindexter, Jose Hernandez, Kathryn (Kay) Hire and Barry (Butch) Wilmore.

As each crew member is suited for launch, orange glow sticks are tucked into the shoulder pockets on their upper arms. Like the orange suits themselves, the glow sticks are intended to give the astronauts a means of identifying one another in the unlikely event of an emergency landing in darkness.

12:19 p.m. - The astronauts have specific seating designations for each launch. Often the seating arrangement is changed for descent. There is room for up to four seats in the mid-deck. Shuttle Commander Steve Lindsey will be the first astronaut to board Discovery. He will have the forward-left seat on the flight deck.

12:18 p.m. - The weather conditions are back to green for launch. The crew has reached the pad and they are about to enter the elevator to head up to the White Room, which is at the 195-foot level of the launch pad service structure.

Did you know?
Discovery will deliver a third crew member to live aboard the International Space Station. It will be the first time a three-person crew resides on station for a long duration since the Expedition 6 crew returned to Earth May 4, 2003.

12:00 p.m. - After suiting up, the seven STS-121 crew members leave the Operations and Checkout Building and board the "Astrovan" that takes them to Launch Pad 39B at NASA's Kennedy Space Center. During the 25-minute ride to the pad, their convoy is accompanied by a helicopter escort.
+ View Astronaut Walk-out

11:58 a.m. - The astronauts are leaving their Crew Quarters. They will be entering the "Astrovan," which will make one stop at the Launch Control Center before continuing on to Pad 39B.

11:53 a.m. - Shuttle Weather Officer Kathy Winters recently briefed Launch Director Mike Leinbach that there are some cumulus and anvil clouds in the area and as of this moment we are in a "no-go" status due to weather.

11:53 a.m. - T-3 hours and counting. The clock has resumed ticking down to launch at T-0, which is still scheduled for 3:49 p.m. this afternoon.

11:35 a.m. - With less than 15 minutes remaining in the T-3 hour hold, our updated weather briefing indicates that we are still green with no violation of any weather constraints at this time. Of course, weather will continue to be monitored throughout the countdown.

Did you know?
The crew for each mission typically comes to Kennedy Space Center for training exercises. One of these is the Crew Equipment Interface Test (CEIT). + Read More

Did you know?
Shuttle Discovery's first flight was Mission STS-41D on August 30, 1984.

10:49 a.m. - All seven astronauts are beginning to dress in their pumpkin-orange launch and entry spacesuits. After final adjustments are completed, the crew will depart for the Launch Control Center where a briefing will be given to management on what was seen on the vehicle and pad structures during the inspections earlier this morning.

10:44 a.m. - We are still in our planned T-3 hour hold. The Ice Team is now at the MLP level of the launch pad and finishing up their inspection. They are using a portable infrared scanner that gathers temperature measurements on the surface area of the shuttle. Their preliminary reports indicate no issues at this time.

Did you know?
That the silver or gold wings on the astronaut blue jumpsuits indicate that they are either in the Air Force or Navy. Silver denotes the Air Force and gold indicates Navy.

10:27 a.m. - The Ice Team is continuing its inspection for ice and debris on the shuttle. They will also inspect the external tank. Once they are finished, they will report their findings to Launch Director Mike Leinbach in Firing Room 4.

10:11 a.m. - In the dining room of the Astronaut Crew Quarters, the STS-121 crew is enjoying the traditional prelaunch cake decorated with the mission's insignia. After they finish eating their cake, the crew will suit-up and receive the latest weather briefing.

10:00 a.m. - T-3 hours and holding. Good morning and welcome to NASA's Launch Blog. The sun is shining brightly on Space Shuttle Discovery poised on Launch Pad 39B and the countdown is continuing toward a launch time of 3:49 p.m. this afternoon. The skies are cerulean blue. Kathy Winters, shuttle weather officer, forecasts a 60-percent chance of weather prohibiting a Kennedy launch this afternoon, mostly due to inland thunderstorms and lightning-producing anvil clouds.

10:00 a.m. - From the Launch Control Center's Firing Room 4 at NASA's Kennedy Space Center in Florida, Commentator Bruce Buckingham opens live coverage of the countdown to launch of STS-121, Discovery's mission to the International Space Station.
+ View Opening Commentary

The following events took place before the start of live coverage:

Last evening at 7:48 p.m. the Rotating Service Structure (RSS) began rolling back in readiness for the start of tanking this morning. Tanking is the term used for the filling of Discovery's external tank with liquid propellants.

The Mission Management Team had their prefueling meeting at 4:45 a.m. this morning and agreed to go ahead with tanking. Fueling operations began at approximately 6 a.m. with the chilldown thermal conditioning of the propellant lines and Discovery's plumbing. The chilldown prepares the systems for the shock of the approximately 500,000 gallons super-cold cryogenic liquid oxygen and liquid hydrogen fuels that will be pumped into the external tank.

The engine cut-off (ECO) sensors in the external tank have been tested during this time and all four are performing as expected.

The only possible issue in work is the examination by officials of a heater problem with one of the vernier engine thrusters onboard Discovery. There is still plenty of time left in the countdown for them to discuss how this will be handled.

We have entered the T-3 hour built-in hold at 8:53 a.m. and word has been received that we have gone into stable liquid oxygen and hydrogen replenish to keep the tank topped off through the rest of the countdown. This hold will last for three hours -- one hour longer than the usual two hours in order to give the final inspection team more time to complete the checks of the shuttle's exterior after fueling.

The tanking of 528,000 gallons of the liquid oxygen and hydrogen was completed this morning as we entered the T-3 hour hold and took a total of 2 hours and 53 minutes to complete.

The MILA Tracking Station here at Merritt Island has configured its communications antennas for launch and the initial communications checks with the Air Force-controlled Eastern Range have been performed.

The Final Inspection Team and the Closeout Crew were given the all clear to head out through the roadblock to the pad at 9:01 a.m. The Final Inspection Team, also known as the "Ice Team," will begin the inspection of the shuttle for ice and debris once they arrive at the pad.

The Orbiter Closeout Crew has arrived at the White Room connected to the end of the Orbiter Access Arm catwalk that extends to Discovery's crew module. They will make the final preparations for the astronaut's arrival at the pad about two hours from now.

The Ice Team arrived at Pad 39B and is beginning their inspections from the 255-foot level. They will continue to inspect the entire shuttle, finishing their survey at the Mobile Launcher Platform (MLP) level. This inspection usually takes approximately two hours.

The Ice Team is composed of seven NASA and contractor members, who carry binoculars and a telescope to get a better look at the hard-to-see areas. The team objective is to assess the integrity of the thermal insulation on the external tank. They also look for ice and frost formations on the tank, measure temperatures on various parts of the vehicle, as well as assess debris concerns on the shuttle and pad that could impact launch or flight safety.

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