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Endeavour to depart the space station today BY WILLIAM HARWOOD STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION Posted: August 19, 2007 The Endeavour astronauts are preparing to undock from the international space station today after a busy, at times dramatic, nine days of orbital construction and supply transfer work. Hatches between the two spacecraft were closed Saturday and if all goes well, the shuttle will undock around 7:57 a.m. Because the crew has had only a few hours of off-duty time since the mission began, flight controllers designed a straight-forward fly away, eliminating a slow loop around the station for photo documentation to give the astronauts a few more hours off at the end of the day. The second of two rocket firings at 8:54 a.m. will complete the undocking and separation procedure. Along with beginning the process of packing up for landing Tuesday, the astronauts plan to carry out a final inspection of the shuttle's nose cap and wing leading edge panels, which experience the most extreme heating during re-entry. A similar inspection was carried out Aug. 9, the day after launch, to look for signs of ascent impact damage. This time around, the astronauts are looking for any signs of damage from space debris or micrometeoroids that might have occurred since the initial inspection. The late inspection is scheduled to begin around 10:15 a.m. A laser scanner and high-resolution camera on the end of a 50-foot-long boom attached to the shuttle's robot arm will be slowly moved back and forth along the right wing leading edge panels, the carbon composite nose cap and then the left wing. The work should be finished by around 2:30 p.m. Impact sensors mounted directly behind the leading edge panels have recorded 16 events corresponding to shocks ranging in strength from 0.5 to 2 Gs. Similar shocks have been recorded on previous post-Columbia shuttle flights, but no obvious signs of actual impacts were detected during late inspection. Engineers believe the events may be associated with thermal stress as the shuttle's structure responds to changes in temperature. "The magnitudes seen on STS-118 have been very similar to previous missions although there has been a 50 percent increase in the number of indications compared to previous flights," NASA's Mission Management Team told the astronauts in a note uplinked Saturday as part of the crew's daily execute package. "This may be attributed to the fact that improvements have been made to the system to provide data simultaneously for both wings for longer periods of time and at colder temperatures. For example, the monitoring time during STS-118 before docking is twice as much as STS-117 and about three times that of STS-116. "Most of the indications, a majority of which occurred on the port wing, were clustered early in the mission prior to and after docking. A few of the wing leading edge indications on previous flights have been correlated to minor impacts found on the wing leading edge panels during post-landing inspections. Many of the other WLE (wing leading edge) sensor indications from previous flights have not been correlated with anything including thruster firings, other mission events, thermal day/night cycles, etc. Many theories exist as to what has caused an increased number of wing leading edge indications on STS-118 including MMOD and the Perseid meteor activity. However, no definitive correlations were found between the Perseids and the increased indications since half of the indications occurred during Earth blockage. Only a single indication occurred during the Perseids peak with both wings being continuously monitored. Obviously, the MMOD (micrometeoroid/orbital debris) concern is the primary reason for executing the late inspection." Here is an updated timeline of today's activity in space (in EDT and mission elapsed time; note: NASA rounds down to the nearest minute; this page rounds up or down as required): EDT........DD...HH...MM...EVENT 08/19/07 04:37 AM...10...10...00...STS crew wakeup 06:17 AM...10...11...40...Group B computer power up 06:33 AM...10...11...56...Sunrise 07:01 AM...10...12...24...Noon 07:12 AM...10...12...35...Undocking timeline begins 07:28 AM...10...12...51...Sunset 07:57 AM...10...13...20...Undocking 07:57 AM...10...13...20...Initial orbiter separation (+10 seconds) 07:58 AM...10...13...21...Space station holds current attitude 08:01 AM...10...13...24...Range: 50 feet; reselect -X jets 08:02 AM...10...13...25...Range: 75 feet; low-Z jets 08:05 AM...10...13...28...Sunrise 08:26 AM...10...13...49...Range: 400 feet 08:26 AM...10...13...49...Separation burn No. 1 08:32 AM...10...13...55...Range: 600 feet 08:32 AM...10...13...55...Noon 08:54 AM...10...14...17...Separation burn No. 2 09:00 AM...10...14...23...Sunset 09:02 AM...10...14...25...ISS: Shuttle docking port depressurization 09:07 AM...10...14...30...Group B computer power down 09:07 AM...10...14...30...Post-undocking laptop computer reconfiguration 09:07 AM...10...14...30...Supply transfer cleanup 09:27 AM...10...14...50...Shuttle arm (SRMS) unberths inspection boom 10:17 AM...10...15...40...Starboard wing survey 10:52 AM...10...16...15...Spacesuit install in airlock 11:02 AM...10...16...25...EVA tool stow 11:57 AM...10...17...20...Nose cap survey 12:57 PM...10...18...20...Port wing survey 01:27 PM...10...18...50...ISS: Shuttle docking port leak check 02:42 PM...10...20...05...Inspection boom berthing 03:17 PM...10...20...40...SRMS power down 03:27 PM...10...20...50...Laser data downlink 03:32 PM...10...20...55...Crew meal 04:32 PM...10...21...55...Crew off duty 08:37 PM...11...02...00...STS crew sleep begins The Mission Management Team continues to monitor the progress of Hurricane Dean. Concern about Dean's track and the possibility mission control at the Johnson Space Center might have to be evacuated prompted NASA to move undocking up one day and bring Endeavour back to Earth Tuesday - one day early - to ensure a Houston-controlled re-entry. On Sunday, the MMT decided that if Hurricane Dean threatened the Johnson Space Center, Endeavour would land Tuesday at one of NASA's three shuttle landing facilities - the Kennedy Space Center in Florida, Edwards Air Force Base, Calif., or White Sands Space Harbor, N.M. If the storm did not pose a threat, the astronauts would attempt to land at Kennedy on Tuesday and, if conditions there were not acceptable, remain in orbit another day and try again on Wednesday. The shuttle has enough on-board supplies to remain in orbit until Friday if worse comes to worse. Over the past few days, Hurricane Dean's predicted path has been creeping south and today's 5 a.m. forecast from the National Hurricane Center showed Dean crossing the heart of the Yucatan Peninsula early Tuesday before hitting the central Mexican coast late Wednesday or early Thursday. The cone of uncertainty has moved well away from Houston. If the storm stays on that track, NASA likely will execute its normal entry strategy, focusing solely on a Florida landing Tuesday and, barring that, a landing at Kennedy or Edwards on Wednesday. The early forecast for Tuesday at Kennedy calls for general favorable conditions with a slight chance of showers in the area. Touchdown is targeted for 12:32 p.m.
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