Back to newsletter listDate:
Mon, March 24, 2008 12:50:17 PMFrom:
CBS Space News
Subject:
1240p 3/24 Update: Shuttle crew preps for undocking
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CBS NEWS STS-123 STATUS REPORT: 64
Posted: 12:30 PM, 3/24/08
By William Harwood
CBS News Space Analyst
Changes and additions:
SR-62 (03/23/08): Debris impact does not appear to be cause of SARJ problem; mission status briefing
SR-63 (03/23/08): Crew takes half-day off; prepares for undocking Monday
SR-64 (03/23/08): Astronauts prepare for undocking
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12:30 PM, 3/23/08, Update: Astronauts prepare for farewell, undocking
The Endeavour astronauts are gearing up to undock from the international space station this evening to close out a marathon five-spacewalk assembly mission. A brief farewell ceremony is planned for 5:13 p.m., followed by hatch closure around 5:30 p.m. With shuttle pilot Gregory Johnson at the controls, Endeavour is scheduled to disconnect from the space station's forward docking port, pressurized mating adapter No. 2, at 7:56 p.m. After looping around the lab complex for a photo survey, Johnson will fire the shuttle's maneuvering jets to leave the area around 9:40 p.m.
"There are a number of key steps both vehicles have to go through to make sure the undocking goes smoothly," said space station Flight Director Bob Dempsey. "First of all, we have to maneuver the combined space station-orbiter vehicle to the undocking attitude, as it's called. Normally, when the orbiter's docked there, the PMA-2, or the pressurized mating adapter 2 (docking port) is flying in the direction the vehicle is going. When the orbiter is docked, we actually flip the vehicle 180 degrees around ... so the delicate thermal protection system on the orbiter, the tiles, are not into the wind, as we say, and vulnerable to debris strikes. So we fly with the shuttle sort of in the back with the belly sort of facing downwind.
"But we can't undock in that position. So we will flip the station around 180 degrees to get them in the right orientation. Then another thing we will do to get ready for the undock is we will park the KU antenna on the space station. We do that so we don't radiate the orbiter. ... And then we will begin a series of minor power downs. The reason we're doing that is, the next thing we have to do is configure the solar arrays on the space station, both the giant U.S. arrays and the Russian arrays, so that as the orbiter's undocking and it's firing its thrusters, that impinges material that can dirty up and push, do some structural damage, to the solar arrays. So we park those so they're kind of edge on to the thrusters so when the orbiter's backing away, we minimize the amount of impact to the solar arrays.
"So once we do all those things, we're in the undocking configuration," Dempsey said. "The shuttle will give the commands and back off from the space station. It'll move away slowly, we don't want to impart a big moment to the space station and push it very hard, cause it to tumble or anything like that. So it'll back off slowly and once the crew gets far enough away, they'll start some minor thruster firings, do it as gently as possible ... then they'll actually do a fly around."
Johnson will guide Endeavour through a full 360-degree loop, flying directly above, behind and below the station for a detailed photo survey.
"That's going to be a great thing for a pilot," Johnson told CBS News before launch. "Undocking is about the opposite of docking, you're leaving the space station at a pretty controlled rate. And then at the end of the undocking timeline, when we get about 300 to 400 feet away, then we start what's called a fly-around and that's where you take the orbiter and go 360 degrees all the way around the station, about 45 minutes of flying. You get to see angles of space station that aren't normally observed and just a great, exciting period for the whole crew."
When the shuttle is a safe distance away, station commander Peggy Whitson, flight engineer Yuri Malenchenko and newly arrived flight engineer Garrett Reisman will begin work to put the station back into its normal operating mode, putting the solar arrays back in sun-track and powering up systems that were shut down earlier. Because of ongoing problems with one of the station's solar array rotary joints, the S4 solar panels on the right side of the complex will remain locked in place.
Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision L of the NASA television schedule):
EDT........DD...HH...MM...EVENT
03/24/08
11:43 AM...13...09...15...Crew wakeup
02:58 PM...13...12...30...Spacesuits transferred to shuttle
04:13 PM...13...13...45...Oxygen system teardown
05:13 PM...13...14...45...Farewell ceremony
05:28 PM...13...15...00...Hatch closure
05:33 PM...13...15...05...Group B computer powerup
05:58 PM...13...15...30...Leak checks
06:39 PM...13...16...11...ISS maneuvers to undocking attitude
06:42 PM...13...16...14...Sunrise
06:43 PM...13...16...15...Centerline camera setup
07:09 PM...13...16...41...ISS in undocking attitude
07:13 PM...13...16...45...Noon
07:13 PM...13...16...45...Undocking timeline begins
07:21 PM...13...16...53...US solar arrays in undocking configuration
07:23 PM...13...16...55...PMA-2 departure config
07:44 PM...13...17...16...Sunset
07:56 PM...13...17...28...UNDOCKING
07:58 PM...13...17...30...ISS holds attitude
08:01 PM...13...17...33...Range: 50 feet; reselect -X jets
08:03 PM...13...17...35...Range 75 feet; low Z
08:13 PM...13...17...45...Sunrise
08:25 PM...13...17...57...Range: 400 feet; start fly around
08:34 PM...13...18...06...Range: 600 feet
08:36 PM...13...18...08...Shuttle directly above ISS
08:40 PM...13...18...12...ISS in TEA attitude
08:44 PM...13...18...16...Noon
08:48 PM...13...18...20...Shuttle directly behind ISS
08:59 PM...13...18...31...Shuttle directly below ISS
09:11 PM...13...18...43...Separation burn No. 1
09:15 PM...13...18...47...Sunset
09:39 PM...13...19...11...Separation burn No. 2
09:43 PM...13...19...15...Post undocking computer reconfig
09:45 PM...13...19...17...Sunrise
10:28 PM...13...20...00...Group B computer powerdown
10:28 PM...13...20...00...PMA-2 leak checks
10:30 PM...13...20...02...Mission status briefing on NASA TV
10:58 PM...13...20...30...ISS crew sleep begins
11:03 PM...13...20...35...EVA unpack and stow
11:03 PM...13...20...35...Undocking videoi replay
11:28 PM...13...21...00...Shuttle arm (SRMS) powerdown
03/25/08
02:58 AM...14...00...30...Crew sleep begins
03:00 AM...14...00...32...Daily video highlights reel on NASA TV
The fly around, Dempsey said, is "a good chance for us to really view the space station all the way around."
"The orbiter crew will be taking all kinds of high resolution photos of the space station and we can use that to check the configuration, make sure everything looks healthy. We will get some baseline photos of the JLP, the Japanese pressurized module that we just installed during this mission and then over time, we'll be able to compare those to other photos ... and just monitor over time. So it gives us a good opportunity to check out the space station."
Departing station crews normally carry out a detailed heat shield inspection just after undocking to make sure the orbiter's nose cap and wing leading edge panels were in good shape for re-entry. Endeavour's crew did that inspection Friday and stowed the shuttle's inspection boom on the station during a spacewalk Saturday so it will be available to the next station assembly crew. Because of interference issues with the Japanese Kibo research module scheduled for launch in May, there was not enough room to carry an inspection boom on that mission.
If all goes well, Johnson, commander Dominic Gorie, flight engineer Michael Foreman, Richard Linnehan, Robert Behnken, Japanese astronaut Takao Doi and returning European Space Agency astronaut Leopold Eyharts will pack up Tuesday and prepare the ship for landing Wednesday evening at the Kennedy Space Center.
Landing is targeted for 7:05:08 p.m. Wednesday and forecasters are calling for good weather, with scattered clouds at 3,500 feet and winds out of the north at eight knots, gusting to 12. A second landing opportunity is available one orbit later, at 8:39:06 p.m.
"I know we're still three days out from landing but the weather is looking pretty reasonable," astronaut Terry Virts radioed the shuttle Sunday evening. "For now it looks good. We'll keep our fingers crossed."
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Quick-Launch Web Links:
CBS News STS-123 Status Reports:
http://www.cbsnews.com/network/news/space/current.html
CBS News STS-123 Quick-Look Page:
http://www.cbsnews.com/network/news/space/currentglance.html
NASA Shuttle Web: http://spaceflight.nasa.gov/shuttle/index.html
NASA Station Web: http://spaceflight.nasa.gov/station/index.html
Spaceflight Now: http://spaceflightnow.com/index.html
GoogleSatTrack: http://www.lizard-tail.com/isana/tracking/
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