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APU 1 runs normally during control system checkout BY WILLIAM HARWOOD STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION Posted: July 16, 2006 A hydraulic power unit with a leak in its fuel system was fired up early today as part of an otherwise routine flight control system checkout aboard the shuttle Discovery. A quick look at telemetry from APU 1 indicated normal operation and no obvious problems, but it will take several hours to make sure the leak rate stayed constant as engineers predicted. Shuttle commander Steve Lindsey and pilot Mark Kelly began the hydraulic power test portion of FCS checkout around 4 a.m., turning on APU 1 to test the hydraulic actuators that will be used for steering during re-entry Monday. "Discovery, Houston, just for a summary of part one three, we saw normal activity on all of the secondary actuator check," astronaut Steve Frick radioed from mission control in Houston. "Everything looked good to us. Also, the quick look on APU 1, we saw normal fuel useage, normal parameters for all of its run time." "OK, great news," Lindsey replied. "Thank you, Steve." APU 1 is on of three redundant powerplants in the shuttle's main engine compartment that generate the hydraulic pressure needed to move the ship's wing flaps, rudder, body flap and landing gear. The pressure in APU 1's hydrazine fuel tank has been dropping ever so slightly since launch July 4, indicating a leak of either nitrogen gas, used to pressurize the tank, or a leak of toxic hydrazine. Because engineers cannot tell which material is leaking, mission managers have to assume it's hydrazine, an extremely hazardous material, and plan accordingly. Mission Management Team Chairman John Shannon said Saturday the team's strategy was as follows: If the leak stayed constant during the FCS checkout, APU 1 will be considered healthy enough for normal use during entry. If the leak worsened, the astronauts will simply run APU 1 until all of its fuel is exhausted and then return to Earth Monday with two operational APUs. "It will be a good test for us, because it will start the APU up, it will run the APU, it will put it through some vibration, all the things we would expect to do prior to entry," Shannon said. "And then we'll just go and assess the leak. "I would sway it's going to take between six and 12 hours to see if the pressure decay rate has changed at all. If there's a significant change, then the ops team will go burn it off just because you would have lost confidence in the integrity of the system. I don't expect that to happen." Based on the quick-look data, no immediately obvious change was seen. Here is an updated timeline of today's activity in space (in EDT and mission elapsed time; includes revision Q of the NASA TV schedule): TIME DD HH MM EVENT 01:08 AM 11 10 30 Crew wakeup (flight day 13) 03:58 AM 11 13 20 FCS checkout 05:08 AM 11 14 30 Cabin stow begins 05:08 AM 11 14 30 RCS hotfire 08:58 AM 11 18 20 Crew meal 09:58 AM 11 19 20 L-1 communications check 1 09:58 AM 11 19 20 Entry video setup 11:38 AM 11 21 00 L-1 communications check 2 12:03 PM 11 21 25 PAO event (all crew members) 12:23 PM 11 21 45 Deorbit briefing 12:30 PM 11 21 52 Mission status briefing on NASA TV 12:53 PM 11 22 15 PILOT landing training 01:08 PM 11 22 30 Wing leading edge gear stow 01:28 PM 11 22 50 Laptop computer teardown 01:33 PM 11 22 55 Ergometer stow 01:58 PM 11 23 20 NC7 rocket firing 02:03 PM 11 23 25 KU antenna stow 05:08 PM 12 02 30 Crew sleep begins 06:00 PM 12 03 22 Daily video highlights reel on NASA TV In the crew's morning "execute package" of timeline changes and instructions from mission control, flight controllers jokingly signed off after a successful mission. "This is the last execute package you're going to get from us," flight controllers wrote. "We've had it. We're done with execute packages, finished, over, our cooked indicator has popped, the fat lady is singing (and she's not singing the Aggie War Hymn). No more... O.K., maybe that's a little bit of an exaggeration. "Actually, if the truth be told, we really have enjoyed working this mission and if the Ku antenna wasn't going to be stowed (today), we would gladly do another execute package. Thanks for making this a great mission - one we're proud to be part of. Take care and see you back in Houston - and we'll buy the first adult malted beverage." Flight controllers have updated deorbit burn and landing times for the shuttle Discovery. Here are all the landing times and sites from Monday through Wednesday (in EDT and subject to change): SITE..REV...DEORBIT.....LANDING Monday, July 17 KSC...202...08:07 a.m...09:14 a.m. (planned) NOR...203...09:42 a.m...10:46 a.m. KSC...203...09:43 a.m...10:50 a.m. EDW...204...11:19 a.m...12:20 p.m. NOR...204...11:22 a.m...12:21 p.m. EDW...205...12:56 p.m...01:54 p.m. Tuesday, July 18 KSC...218...08:19 a.m...09:21 a.m. EDW...219...09:48 a.m...10:50 a.m. NOR...219...09:50 a.m...10:52 a.m. KSC...219...09:56 a.m...10:56 a.m. EDW...220...11:23 a.m...12:24 p.m. NOR...220...11:26 a.m...12:26 p.m. EDW...221...01:01 p.m...01:58 P.m. Wednesday, July 19 KSC...233...06:47 a.m...07:51 a.m. KSC...234...08:23 a.m...09:25 a.m. EDW...235...09:52 a.m...10:54 a.m. NOR...235...09:54 a.m...10:56 a.m. EDW...236...11:28 a.m...12:28 p.m. NOR...236...11:31 a.m...12:30 p.m.
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VIDEO:
DISCOVERY'S UNDOCKING FROM STATION EXPLAINED 