SM3A Live Coverage
Dec. 26-27 Day 8 - Landing Day
Landing Day! An initial concern regarding crosswinds at the landing site at Kennedy Space Center made the NASA officials cancel the first landing attempt. At the time of the second attempt, one orbit later, the Sun was almost setting over Kennedy Space Center and the crosswinds had died out. The crew was told to begin "fluid loading", which is a technical term for drinking ample amounts of lime-flavoured salt water. This is also a clear sign that the landing is going to take place soon. The fluid loading is necessary to prevent the astronaut from fainting from low blood pressure and dehydration when they return to the gravity on Earth.
At 23:48 CET the so-called pre-orbit burn began. This is the manoeuvre that will enable the Shuttle to enter the atmosphere as the first step of the landing procedure.
00:15 on Dec. 28 Discovery entered the atmosphere and started to slow down. At 01:01 CET the landing occurred and the third Hubble Servicing Mission was over.
Dec. 25-26 Day 7
The last full working day of Servicing Mission 3A did also pass without any problems. After breakfast the crew started the day with a news conference. They then prepared for the landing by stowing all loose objects and exercised a bit. It was a slightly "slow" day without too much action - and rightfully so, after the all the important and successful work they have carried out in the previous days.
Dec. 24-25 Day 6 - Release
The sixth working day onboard the Shuttle Discovery (officially flight Day 7) was the day of the release of Hubble. At 21:01 CET Jean-Francois Clervoy grabbed hold of Hubble with the robotic arm and at 22:20 he lifted the telescope out of the payload bay.
At 23:28 Hubble's aperture door was opened for the first time since the telescope went into safe mode on November 13. This procedure went on without any problems and at 00:03 CET on Dec. 26 Hubble was released with Discovery slowly backing away. Only minutes later Hubble started a slow rotation to point the telescope away from the Sun.
At 00:27 Hubble reached another milestone: A long awaited return to normal gyroscope control for the first time in more than a month!
Dec. 23-24 Day 5 - EVA 3
The third spacewalk of Servicing Mission 3A was also performed flawlessly. The tasks on this spacewalk included finishing the installation of the fine guidance sensor, which was installed during the second spacewalk, together with replacement of a faulty radio transmitter and a data tape recorder. Additionally installation of thermal insulation was on today's to do-list for the astronauts.
Within the first hour of leaving the air hatch astronauts Grunsfeld and Smith had installed an optical control electronics package for the fine guidance sensor. They immediately moved on to the rather difficult task of replacing the S-band radio transmitter. This unit failed in 1998, but the other transmitter has so far been able to handle the communication tasks alone. The unit was never meant to be changed in space and John Grunsfeld required all his concentration to remove small bolts and connectors wearing the big gloves of his spacesuit.
Amazingly the work went smoothly and the team pressed on with the installation of a new solid-state data recorder that replaced the old reel-to-reel tape recorder. Again there were no problems and initial tests of both the transmitter and recorder showed no problems. The new recorder not only uses better technology (solid state memory chips) for storing the observation data, but it will also be able to store 10 times more data (1.5 Gbyte). The ability to simultaneously record and play back data, in addition to having access all data at once makes this recorder a big improvement taking Hubble into the new millenium.
The last work to be done was the replacement of thermal insulation on Hubble's outside. Time constraints meant that the work had to stop after installation of insulation on two of the equipment bays, but still the accomplishments of this servicing mission are truly outstanding!
It now seems that Hubble will not only be able to work again after more than two months of downtime, but will be able to work much more efficiently than before. Final tests will be carried out before Hubble's release Sunday 26 December at 00:03 CET.
Dec. 23-24 Day 4 - EVA 2
The fourth working day in space (officially counted as Flight Day 5) is over and everything went well. The night's spacewalk was another one for the record books, 8 hours and 10 minutes, making it the third longest spacewalk in history. The longest was the third spacewalk during STS-49 in 1992 which lasted 8 hours and 29 minutes. The second longest was yesterday's spacewalk which lasted 8 hours and 15 minutes.
Astronauts Nicollier from ESA and Foale from NASA carried out the tasks - the exchange of Hubble's computer and a Fine Guidance Sensor - without any serious problems. The work with the computer began at 20:54 CET, and was finished 22:20 CET. The fine guidance sensor was in place 02:11 CET (Dec. 24), after some minutes of tension where Nicollier and Foale worked intensively on sliding the sensor on place.
Following the exchange the computer and the fine guidance sensor were "aliveness" tested. Both were found to be correctly installed. More testing will be carried out while the astronauts sleep - between 07:50 - 15:50 CET (on Dec. 24).
The new computer is a 486 model and it will be 20 times faster and have six times as much memory as the previous model - a socalled DF-224 designed in the 70's. The reason for not sending up the latest computer equipment to space is a demand for a flawless operation in the very harsh environment in space. The lifetime of the 486 is expected to exceed the 10 years Hubble itself is expected to be in operation. Despite being bombarded by cosmic and solar radiation constantly and being exposed to extreme temperatures.
There are three fine guidance sensors on Hubble. Two are all the time being used to point Hubble at the objects being observed. The third can then be used to make a special type of observations known as astrometry. Astrometry deals with the determination of precise positions and motions of stars.
The next spacewalk will be this mission's third and last. It will begin at 20:40 CET.
The tasks are:
|0:15-0:45 Finalizing the installation of fine guidance sensor.
|0:45-2:00 Replacement of S-Band transmitter.
|2:00-3:00 Replacement of Solid State Recorder.
|3:15-5:30 Repair of thermal insulation.
Dec. 22-23 Day 3 - EVA 1
Update for Thursday Dec. 23, 05:15 CET
The astronauts will go to sleep around 7:40 CET. The next spacewalk is scheduled for 20:40 CET later this evening. The plan for this second spacewalk on this mission is:
|Replacement of the computer.
|Replacement of Fine Guidance Sensor 2.
Update for Thursday Dec. 23, 04:15 CET
The spacewalk ended officially at 04:10 CET which means that the total duration was 8 hours and 15 minutes. Only one earlier spacewalk, during STS-49, lasted longer - 8 hours 29 minutes.
Update for Thursday Dec. 23, 03:45 CET
The astronauts are now entering the airlock after one of the longest spacewalks in history. The aliveness test for the VIKs turned out positive.
Update for Thursday Dec. 23, 03:30 CET
The crew have now almost finished cleaning the Shuttle bay for tools and equipment. In 20-25 minutes the spacewalk should end.
Update for Thursday Dec. 23, 03:05 CET
The last remaining three VIKs have now been installed.
Update for Thursday Dec. 23, 02:35 CET
Grunsfeld has installed three of the voltage/temperature kits (VIKs), and as a little bonus, Smith has at the same time installed some of the handrailing covers. It has now been decided to install the last three VIKs anyway.
Update for Thursday Dec. 23, 01:55 CET
Smith and Grunsfeld had some problems closing the aft shroud doors. These doors are rather large and a somewhat wobbly. It took a little bit of effort and some time. In fact the team on the First Servicing Mission also had problems closing these doors, but at least this time it went much easier. Due to the time constraints it has been suggested that the team will only change three of the six voltage/temperature kits tonight. The rest will have to be done tomorrow.
Update for Thursday Dec. 23, 01:15 CET
The NICMOS tasks are now completed.
Update for Thursday Dec. 23, 00:38 CET
The crew will now move back to the NICMOS valves and try to force them open.
Update for Thursday Dec. 23, 00:22 CET
It has been confirmed that the third gyro-pair is working. This means that we can say that Hubble has now been repaired! The rest of the mission will mainly be concerned with improvements of Hubble's capabilities.
Update for Thursday Dec. 23, 00:15 CET
The NICMOS task did not succeed, but they have photographed the valves and may return later. Now the team presses on with installation of the temperature/voltage kits which are going to prevent overheating of the batteries onboard. Smith and Grunsfeld have been spacewalking for 4 hours and 20 minutes now.
Update for Thursday Dec. 23, 00:00 CET
The next task is to remove caps on coolant valves on the NICMOS (Near Infrared Camera and Multi-Object Spectrometer) instrument. This is necessary in order to get rid of any left-over nitrogen coolant as a preparation for the installation of a new NICMOS cooler on the next Servicing Mission (SM3B scheduled for 2001). This operation should only take about 15 minutes..
Update for Wednesday Dec. 22, 23:45 CET
The last set of two gyros have now been replaced! The aliveness test is still to be performed.
Update for Wednesday Dec. 22, 23:15 CET
The work is progressing well. STOCC confirmed that the first new set of gyros work. The second set has been installed and are also working perfect.
pdate for Wednesday Dec. 22, 22:35 CET
The first two gyros have been replaced. STOCC will now perform an aliveness test to ensure that the two gyros work.
Update for Wednesday Dec. 22, 22:15 CET
The first of the old gyro-sets have been removed and are being stowed.
Update for Wednesday Dec. 22, 21:22 CET
The first set of two gyros has been "turned off" by the crew in the Space Telescope Operations Control Center (STOCC). The new gyro has been unpacked,
Update for Wednesday Dec. 22, 20:55 CET
The set-up is about done now. Next task is the replacement of the gyros.
Update for Wednesday Dec. 22, 20:35 CET
Steve Smith examines some of the handrails on the telescope (which was actually put there for the astronauts to use). He says that the handrails on the Sun side of the telescope have changed colour, but that there are no flaky paint. The paint flakes have been course for concern since small flakes may find their way into sensitive equipment.
Update for Wednesday Dec. 22, 19:54 CET
Smith and Grunsfeld have now switched the power in their spacesuits from "external" (fed by Discovery) to "internal" and are now moving outside. This is the point where the Servicing Mission begins for real.
Update for Wednesday Dec. 22, 19:47 CET
The Shuttle is now changing its position in space to give the astronauts the best protection from the light and radiation from the Sun.
Update for Wednesday Dec. 22, 19:20 CET
The depressurization of the airlock has begun. NASA expresses optimism regarding the possibility to carry out some of the tasks originally scheduled for the fourth spacewalk during the next three spacewalks.
Update for Wednesday Dec. 22, 19:00 CET
Clervoy has just moved the robotic arm in position. It is now ready to support Smith and Grunsfeld in their work. The exchange of the gyros - which should begin in an hours time and last for three hours - is the single most important task on this mission!
Update for Wednesday Dec. 22, 18:50 CET
The schedule for today's spacewalk looks like this:
|All six gyroscopes will be replaced. They are grouped in pairs in the so-called RSUs (Rate Sensor Units).
|Removal of caps on coolant valves on the NICMOS (Near Infrared Camera and Multi-Object Spectrometer) instrument (preparations for the installation of a new NICMOS cooler on the next Servicing Mission scheduled for 2001).
|Six voltage/temperature kits (to prevent overheating the batteries) will be installed.
We have just received notice from the ground controllers: They have scrutinized the videotapes recorded by the astronauts yesterday, and Hubble does really look like it is in fine shape! Hubble is ready for the first spacewalk.
Update for Wednesday Dec. 22, 18:30 CET
Today's two spacewalkers, Smith and Grunsfeld, have begun breathing pure oxygen before entering the spacesuits which have lower air pressure than the Shuttle. The spacewalk is now scheduled for 19:20 CET, which is more than 1 hour ahead of schedule.
Update for Wednesday Dec. 22, 17:55 CET
The astronauts woke up two hours ago and are now busy preparing for the first spacewalk. The preparations are ahead of schedule and the spacewalk may begin as early as 18:45 CET.
Dec. 21-22 Day 2 - Grapple
Update for Wednesday Dec. 22, 08:50 CET
The astronauts went to sleep an hour ago after a hard working day. Everything went according to schedule.
Update for Wednesday Dec. 22, 03:47 CET
The rest of this working day in space will be spent unpacking and donning equipment for tomorrow's spacewalk. At 7:50 CET the crew will go to sleep for 8 hours.
In a brief comment to the ground the astronauts expressed their satisfaction with the accomplishment of todays tasks, and they thanked the ground crew and everyone participating in the work behind the scene. They also mentioned the beauty of the sight of Hubble getting closer and closer during the rendezvous.
Update for Wednesday Dec. 22, 03:15 CET
Hubble is now being scrutinized with the cameras on the robotic arm. This will continue for an hour or so. The pictures will serve as basis for the whole Hubble project to assess any changes with the telescope or its instruments.
Update for Wednesday Dec. 22, 03:07 CET
Hubble has been connected with the power line from Discovery and are now being fed power directly from here.
Update for Wednesday Dec. 22, 02:33 CET
Hubble has been latched safely in the cargo bay. Now work can begin for real.
Update for Wednesday Dec. 22, 02:15 CET
Discovery has just entered daylight and the first marvellous pictures from one of Discovery's cameras reveal a shiny healthy looking Hubble!
Update for Wednesday Dec. 22, 01:51 CET
When Hubble has been latched in the correct position in the cargo bay one of the first tasks the team will perform is to check the telescope with cameras on the robotic arm.
A curious thing was that the grappling operation happened exactly over Houston where Johnson Space Center, which is controlling this part of the mission, is located. And many people did get a unique sight of Discovery and Hubble together.
Update for Wednesday Dec. 22, 01:40 CET
Clervoy is rotating Hubble with the robotic arm to set it down correctly in the berthing fixtures in the Shuttle bay.
Update for Wednesday Dec. 22, 01:34 CET
Capture has been confirmed! Congratulations! "Hubble grappled" as Clervoy phrases it.
Update for Wednesday Dec. 22, 01:20 CET
40 meters before Hubble is within Clervoy's reach.
The speed is now 0.2 km/hour.
The Space Telescope Operations Control Center (STOCC) has finished their work with the preparations of Hubble for the rendezvous.
Everything is ready! Good luck to Jean-François Clervoy.
Update for Wednesday Dec. 22, 01:05 CET
200 meters. Hubble is rotating very very slowly.
Update for Wednesday Dec. 22, 01:01 CET
300 meters left. The speed is down to 1.5 km/hour. Discovery is positioned directly below Hubble - this means that the astronauts at the moment should be looking up at the opening of telescope (which points down towards Earth).
Update for Wednesday Dec. 22, 00:55 CET
600 meters left. Discovery is approaching Hubble with approximately 3 km/hour. Mission Commander Brown is now taking over manual control of the Shuttle to perform the final sensitive manoeuvres.
Update for Tuesday Dec. 21, 23:50 CET
We have just now received information about the position of Hubble in space. The telescope is pointing somewhat upside-down with respect to the "normal" servicing mission position. That is approximately 180 degrees from this position. Instead of the back end - the socalled aft shroud - pointing downwards to Earth, it is actually the tip of the telescope which is pointing downwards. Mission Commander Brown has trained extensively for this particular case, and it now seems clear that he will have to move the Shuttle around Hubble.
Update for Tuesday Dec. 21, 23:32 CET
The TI burn was successfully carried out. Within the next two hours we should be able to see Hubble through the eyes of the cameras onboard Discovery. The distance is 15 kilometres.
The rendezvous is still planned for 01:41 CET although the time for the capture of Hubble itself will depend somewhat of its actual orientation. Since Hubble is in safe mode using only backup gyros its exact orientation in space is not known.
Commander Brown may have to move Discovery around Hubble in order for Clervoy to be able to grab the telescope with the robotic arm.
Update for Tuesday Dec. 21, 22:28 CET
Next upcoming event will be the final approach manoeuvres - the socalled Terminal Initiation (TI) burn - which will bring Discovery on right course for the rendezvous. The TI will occur at 23:28 CET.
The distance to Hubble is now approximately 40 km and the relative speed of Discovery is 37 km/h. The crew has already some time ago reported to have visual contact with Hubble.
The Space Telescope Operations Control Center (STOCC) at Goddard Space Flight Center, Washington DC, reports that all systems on Hubble are behaving nicely, and that their preparations with the various systems and instruments onboard are going according to the schedule.
Update for Tuesday Dec. 21, 19:32 CET
The engine burn has been performed, and everything went smoothly. Discovery's orbit is now slightly higher, and the speed of the spacecraft has been reduced.
This manoeuvre was performed while Discovery was momentarily "out of sight" from both of the two TDRSS (Tracking and Data Relay Satellite System) satellites relaying the radio communication from the Shuttle to the ground. This happens for a few minutes in every orbit over the Indian Ocean.
Update for Tuesday Dec. 21, 18:40 CET
In about 50 minutes (19:28) the first of a series of engine burns will put Discovery on a direct course for the rendezvous. The next engine burn will happen 45 minutes later.
Discovery has received a "go" for the grappling of Hubble. Still 7 hours to go...
Update for Tuesday Dec. 21, 18:00 CET
The distance between the Shuttle and Hubble is now 350 km and the Shuttle is getting closer with about 240 km every orbit lasting 90 minutes.
Everything is working according to plans and the rendezvous with Hubble is expected to happen 01:41 CET.
Well, in fact there is a minor "problem": A paper jam in a printer used to print mission plans and messages from the ground.
Update for Tuesday Dec. 21, 16:20 CET
The astronaut team have just woken up and are preparing themselves for a day with a bit more action than yesterday.
Today, or more correctly for us Europeans, tonight at 01:40 CET Clervoy will manoeuvre the robotic arm to catch Hubble in the delicate operation known as "grapple".
Dec. 20-21 Day 1
Update for Tuesday Dec. 21, 10:45 CET
The first full day of Servicing Mission 3A is now over and the astronauts have gone back to sleep. Everything went according to plans. Nicollier and Clervoy powered up the robotic arm. Afterwards Clervoy moved a camera on the robotic arm and did, together with the two spacewalk teams Nicollier/Foale, and Smith/Grunsfeld, a thorough check-out of the equipment in the Shuttle cargo bay - the socalled berthing table on which Hubble is going to sit during the spacewalks, and the components they are going to replace. After lunch the pilots Mission Commander Brown and Pilot Kelly set up tools for the rendezvous with Hubble while Nicollier, Foale and Grunsfeld unpacked and checked the spacesuits.
In a brief interview Mission Specialist Foale explained that he personally was convinced that the they would be able to replace the six gyros, install the voltage/temperature kits, change the computer, the Fine Guidance Sensor, the S-band transmitter and the recorder during the three planned spacewalks.
The astronauts will wake up at 16:20 CET. The capture of Hubble is expected to take place at 01:40 CET tonight, Dec. 22.
Update for Monday Dec. 20, 19:25 CET
The seven astronauts woke up at 16:50 CET. They are still in the "post sleep" phase. This basically means waking up, eating breakfast just like any other person. And then naturally also reviewing today's plan carefully which has been updated to reflect the actual launch time. Mission planners have had a hard time following all the changes in the schedules as the launch has been postponed time after another. But everything is now in place.
In a few minutes - around 19:30 CET - the team will begin their duties of the day. The day will mainly be concerned with unpacking tools, checking equipment and spacesuits. Around 7:00 CET tomorrow morning there will be a half hour engine burn manoeuvre to get Discovery in a better orbit for the grappling of Hubble. Other than that the most important issues of the day will be getting everything ready for tomorrow's grappling operation.
Dec. 19-20 launch!
Update for Monday Dec. 20, 02:00 CET
Main engines have shut down. Discovery is safely in orbit.
Update for Monday Dec. 20, 01:58 CET
Discovery has rolled to a heads-up position.
Update for Monday Dec. 20, 01:54 CET
Solid rocket boosters separation. Everything looks fine!
Update for Monday Dec. 20, 01:50 CET
Launch! Space Shuttle Discovery with seven astronauts - five American and two European astronauts - is finally on its way to service the Hubble Space Telescope.
Update for Sunday Dec. 20, 01:41 CET
T-minus 9 minutes and counting. Everything is still "go" for launch.
The following is a schedule of the events that will take place after the launch (adapted from Florida Today). All times are T-plus:
0 seconds - Solid rocket booster ignition and liftoff.
10 seconds - The shuttle will roll the astronauts to a heads-down position.
32 seconds - The shuttle's three main engines will be throttled down to 67 percent of maksimum power. This will put less stress on the shuttle as it passes through the sound barrier.
49 seconds - This is the point where the shuttle has the most stress on it from aerodynamic forces.
56 seconds - The three main engines are returned to full power.
2 minutes 3 seconds - Solid rocket boosters separate.
5 minutes 50 seconds - Discovery rolls to a heads-up position so it can communicate through NASA's Tracking and Data Relay System satellite.
8 minutes 25 seconds - The three main engines cut off.
Seconds later the external tank separates and the shuttle is safely in orbit.
Update for Sunday Dec. 20, 01:01 CET
The last 40 minutes hold at T-minus 9 minutes.
Everything is green for a launch. Keeps those fingers crossed!
Update for Sunday Dec. 20, 00:50 CET
T-minus 20 minutes and counting. Launch is in one hour.
The next build-in hold at T-minus 9 minutes will occur at 01:01 CET and will last 40 minutes.
Update for Sunday Dec. 20, 00:40 CET
T-minus 20 minutes and holding. The clock will now hold for 10 minutes.
The weather indicators are still all green.
Update for Sunday Dec. 19, 23:42 CET
Discovery's hatch has been closed.
Once again ESA Science wishes God Speed to the crew!
Update for Sunday Dec. 19, 23:22 CET
The countdown clock is now at 1 hour 39 minutes.
The next hold will be at T-minus 20 minutes which will occur at 00:40 CET. The clock will then be stopped for 10 minutes. The final hold at T-minus 9 minutes will occur at 01:01 CET and will last for 40 minutes.
Everything is ready for a launch at 01:50 CET.
Update for Sunday Dec. 19, 22:30 CET
The crew has arrived at the pad, and now they enter the white room, from where they can enter the Shuttle. In a little less than one hour all crew members should be in their seats.
All weather indicators remain green at this time.
Update for Sunday Dec. 19, 22:12 CET
The crew has now left their quarters. The countdown clocks have resumed at 22:00 CET.
Everything seems to be "go" for a launch tonight.
Update for Sunday Dec. 19, 21:52 CET
The crew members are now being suited up for the launch.
Update for Sunday Dec. 19, 21:25 CET
The Final Inspection Team has left the launch pad. No problems were reported. The weather still looks promising, and everything is on schedule.
Update for Sunday Dec. 19, 21:00 CET
The Final Inspection Team are inspection the Shuttle and the pad. They are looking for ice build-up and for other abnormalities. The work will be done in approximately 30 minutes.
The countdown is at T-minus 3 hours and holding.
Update for Sunday Dec. 19, 20:48 CET
The fuelling of the Shuttle was complete 19:30 and the tanks are continuously being topped-off. There are no reports of problems and the weather forecast still predicts 80% chance of meeting requirements. The only concern is a small risk for a low cloud ceiling.
Tonight's launch attempt for Servicing Mission 3A is the 10th.
Update for Sunday Dec. 19, 17:17 CET
Fuelling of the Shuttle has begun. There is a sense of optimism over the operation today.
Update for Sunday Dec. 19, 16:20 CET
NASA officials have approved the plan to launch Discovery tonight 1:50 CET on an 8-day mission to repair Hubble.
The weather forecasts looks good: 80% chance for acceptable weather conditions.
Dec. 18-19 launch attempt
Update for Saturday Dec. 18, 18:46 CET
Tonight's launch has been scrubbed! The reason is once again bad weather conditions around Kennedy Space Center. NASA officials will decide whether or not to proceed with the tanking around 16:00 CET tomorrow, Sunday. This will determine whether another attempt to launch will be made early Monday morning 01:50 CET.
Launching Monday means that the fourth spacewalk will have to be cancelled (read more about the spacewalks on SM3A background). Currently weather forecasters predict up to 60% chances for acceptable weather conditions tomorrow.
Read more about the many different restrictions on weather conditions on this NASA Goddard Space flight Center page.
This page will be updated again tomorrow.
Update for Saturday Dec. 18, 18:33 CET
NASA has not yet decided whether to go ahead with the fuelling of the external tank. There is still time in the schedule to make tonight's launch, but the fuelling must begin by 19:00 according to the plan.
Update for Saturday Dec. 18, 17:40 CET
NASA managers have now decided that they - in case of another postponement - will attempt a launch on Monday morning with a launch window between 01:50 and 02:32 CET.
Update for Saturday Dec. 18, 17:09 CET
The weather forecast for tonight's launch at 02:21 CET does unfortunately not look very promising. There is a 70% risk for violations of some of the many weather criteria set by NASA for this ninth attempt to launch the Shuttle on Hubble Servicing Mission 3A. Again a low cloud cover and rain are the looming factors.
One piece of good news is that NASA officials now are investigating whether the post-landing work may be shortened by one day. This would make a launch attempt Monday morning possible. NASA says that it will not launch the Shuttle on this mission if there are less that 8 days available for the work.
Dec. 17-18 launch attempt
Update for Saturday Dec. 18, 02:54 CET
We have a "scrub" - launch has been postponed until tomorrow. The reason being several weather related socalled "violations": Cumulus clouds, disturbed weather, thick clouds, triggered lightning, rain, and cloud ceiling/visibility.
We will again tomorrow monitor the events from the Hubble Servicing Mission ESA Monitoring Centre in ESTEC. The launch window will be open between 02:21 and 3:03 CET.
Update for Saturday Dec. 18, 02:35 CET
NASA Test Director Steve Altemus has announced that the countdown will not start again at the planned 02:38 CET. The T-minus 9 minutes hold will be extended in the hope that the weather situation will improve.
Update for Saturday Dec. 18, 01:58 CET
T-minus 9 and holding. A planned 40 minute hold is being performed. the time will among other things be used to monitor the weather to determine if the launch will be aimed at the first part of the launch window.
The weather does not seem promising at the moment.
Update for Saturday Dec. 18, 01:47 CET
T-minus 20 and counting.
Update for Saturday Dec. 18, 01:38 CET
T-minus 20 and holding. A planned 10-minute hold is being performed.
Update for Saturday Dec. 18, 01:33 CET
The launch window has just been extended with four minutes. The window now stretches to as late as 03:33:32 CET. A launch between 03:29:22 and 03:33:32 CET would mean that Discovery will rendezvous with Hubble on Flight Day 4 as opposed to the originally planned Flight Day 3.
Update for Saturday Dec. 18, 01:27 CET
The countdown clock is ticking toward T-minus 20 minutes where a 10-minute hold is planned. A final built-in hold is scheduled at T-minus 9 minutes and will last for 40 minutes.
The main concern continues to be weather conditions in the local KSC area. The forecast is calling for thick low clouds and rain. It is currently raining at KSC and U.S. Air Force weather officials are not too hopeful for launching Discovery before the end of the 42-minute window.
(Source: Spaceflight Now)
Update for Saturday Dec. 18, 00:45 CET
The crew compartment hatch is being closed.
Update for Saturday Dec. 18, 00:10 CET
The astronauts are now all aboard the Space Shuttle Discovery. Forecasters say that the heaviest rain passed over Kennedy Space Center around 23:30.
"No technical issues are being addressed at this moment" is the message from NASA. But the weather remains critical. If the launch will be postpone, it has been confirmed that NASA will try again tomorrow. The launch window will in this case open approximately 23 1/2 hours after tonight's scheduled launch.
God Speed to you all from ESA Science!
Update for Friday Dec. 17, 23:28 CET
The seven astronauts have reached the launch pad are now preparing to enter the Shuttle. It is still the hope that the frontal system will move to the north before the launch in a little more than three hours.
Update for Friday Dec. 17, 23:14 CET
The team of astronauts have now departed from their quarters and are on their way to the tower.
The weather is still reason for concern.
Update for Friday Dec. 17, 23:05 CET
The team inspecting the orbiter did not find any problems and the countdown clock is no longer on hold - T minus 2 hours 59 minutes.
Update for Friday Dec. 17, 22:49 CET
Countdown is to resume in 15 minutes. The crew has just had a weather briefing, and are now putting on their flight suits. There is a weak frontal system over Florida, but there is some optimism that this front will move to the north. NASA officials anticipate that the weather situation will improve somewhat before launch.
The launch window is 42 minutes and will open at 02:47 CET.
Update for Friday Dec. 17, 22:10 CET
Discovery on Kennedy Space Center launch pad 39B is being checked for signs of ice build-up on the outside of the external tanks. Due to the wet weather there is risk for condensation and following ice build-up on the tanks. So far there has not been found any signs of ice. Indeed very little frost seems visible on the tanks.
In the moment the tanks are continuously being topped off with more fuel as some of the very cold liquid hydrogen and oxygen boils away.
Update for Friday Dec. 17, 21:51 CET
Approximately 1 hour 15 minutes left of the planned hold.
Update for Friday Dec. 17, 21:00 CET
The external tank has been filled with liquid hydrogen and oxygen.
The countdown has entered a two-hour planned hold at T-3 hours.
Update for Friday Dec. 17, 20:00 CET
No problems was found concerning the welding paperwork. The countdown is now ticking although weather conditions do not look favourable. NASA estimates that there is only a mere 20% chance for a launch tonight due to thick cloud layers and possibility of coastal showers.
Preparations for the launch are nevertheless continuing: Discovery's external tank is now almost filled with more than 1,5 million liters of fuel - liquid hydrogen and liquid oxygen.
The schedule for the astronauts looks like this (from Florida Today - times in CET):
17:00 - The crew wakes up to begin their day
23:02 - Astronauts depart for launch pad 39B
00:47 - Discovery's main hatch is closed for flight
02:47 - Launch
Dec. 16 launch attempt
Update for Thursday Dec 16, 17:40 CET
Launch of STS-103 (Hubble Servicing Mission 3A) has been delayed to December 18 02:47 Central European Time. According to NASA officials it is necessary with a more thorough investigation of paperwork regarding welding on the external fuel tank.
A manufacturer of tank components found evidence of a welding flaw on a pressure line for a future external tank. Evaluations of Discovery's tank showed no welding flaws, but engineers are double-checking the paperwork to be sure.