Spaceflight Now





NASA tentatively targets
May 10 for Endeavour launch

BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: May 2, 2011


Bookmark and Share

KENNEDY SPACE CENTER, FL--Work to replace and retest an electrical distribution box in the shuttle Endeavour's engine compartment will push the crew's next launch attempt to at least May 10, agency managers said Monday. An official launch date is expected Friday, after repairs are complete.


Technicians work inside Endeavour's aft compartment. Credit: NASA
See full gallery

 
In the wake of a launch scrub last Friday, NASA managers said Sunday the next attempt to launch Endeavour on its 25th and final mission would be delayed to Mother's Day at least and possibly longer.

A more realistic assessment Monday, based on a detailed review of the work needed to replace the suspect aft load control assembly, showed it would not be possible to complete repairs in time to start a fresh countdown Thursday for a launch on Sunday.

Instead, mission managers agreed to target May 10 as a "no-earlier-than" date pending successful repairs. If that scenario holds up, a fresh countdown would start around 9:30 a.m. EDT (GMT-4) Saturday for a launch attempt at 11:21 a.m. next Tuesday, May 10. But engineers believe it will be difficult to meet that target and that May 11 is a more realistic option.

Endeavour was grounded Friday when telemetry showed hydraulic power system fuel line heaters were not working properly. Subsequent tests isolated the problem to aft load control assembly No. 2 in the shuttle's engine compartment.

The ALCA is one of three electrical switching units in the aft compartment that routes power to a variety of critical systems. Replacing ALCA No. 2 is relatively straight forward, but verifying that all the downstream systems are properly connected and operating is expected to take two full days.

The replacement unit should be in place Tuesday, clearing the way for testing to begin. Engineers also will evaluate the faulty unit to verify the presumed fault.

A launch on May 10 at 11:21 a.m. would set up a docking at the International Space Station around 8:20 a.m. on May 12. The shuttle's primary payload, a $2 billion particle physics experiment, would be attached to the lab's power truss the next day.

Four spacewalks would carried out on May 14, 16, 18 and 20 with undocking on tap around 1:15 a.m. on May 22 and landing back at the Kennedy Space Center around 5:50 a.m. on May 24.

Going into Endeavour's final launch campaign, NASA managers planned to add two days to Endeavour's mission to give the crew more time to help out with needed station maintenance.

But with Friday's launch delay, the prospects for a mission extension are not clear cut because of the scheduled undocking of a Russian Soyuz ferry craft on May 23. Three of the station's six crew members will be returning to Earth that day and they must adjust their sleep shifts to accommodate the re-entry and landing time.

For a launch on May 8, two extension days were still available for Endeavour's crew, assuming an Air Force Atlas rocket gets off on time Friday.

For a launch on May 9, one extension day is available but for a launch on May 10, station crew sleep shifting and other factors would preclude any additional days for the shuttle crew, officials said. For a launch on May 11, both extension days should be available.


Spaceflight Now Plus
Additional coverage for subscribers:
VIDEO: WORKING ON OLD AND NEW SWITCHBOXES PLAY | HI-DEF
VIDEO: LAUNCH OF ENDEAVOUR DELAYED FURTHER PLAY

VIDEO: PRESIDENT OBAMA ARRIVES AT THE CAPE PLAY | HI-DEF
VIDEO: TOUR OF ATLANTIS AND ASTRONAUT MEETING PLAY | HI-DEF
VIDEO: FIRST FAMILY DEPARTS AFTER VISIT PLAY | HI-DEF

VIDEO: POST-SCRUB NEWS BRIEFING PLAY
VIDEO: LAUNCH DIRECTOR EXPLAINS SCRUB CALL PLAY | HI-DEF
VIDEO: SCRUB DECLARED FOR APU NO. 1 HEATER GLITCH PLAY | HI-DEF
VIDEO: ASTRONAUTS LEAVE QUARTERS BEFORE SCRUB PLAY | HI-DEF
VIDEO: CREW GETS SUITED UP FOR LAUNCH PLAY | HI-DEF
VIDEO: TIME-LAPSE OF PAD GANTRY RETRACTING PLAY | HI-DEF

VIDEO: ENDEAVOUR'S PRE-FLIGHT CAMPAIGN PLAY | HI-DEF
VIDEO: PAYLOADS' PRE-FLIGHT CAMPAIGN PLAY | HI-DEF
VIDEO: PREPARING ENDEAVOUR FUEL TANK FOR LAUNCH PLAY | HI-DEF

VIDEO: COUNTDOWN UPDATE AND WEATHER BRIEFING PLAY
VIDEO: THE PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: ASTRONAUTS ARRIVE AT LAUNCH SITE PLAY | HI-DEF
VIDEO: COUNTDOWN PREVIEW BRIEFING PLAY | HI-DEF

VIDEO: GUIDED TOUR OF SPACE STATION PLAY | HI-DEF
VIDEO: ENDEAVOUR MISSION PREVIEW MOVIE PLAY | HI-DEF
VIDEO: GET TO KNOW ENDEAVOUR'S ASTRONAUTS PLAY | HI-DEF

VIDEO: PRE-FLIGHT INTERVIEW WITH MARK KELLY PLAY
VIDEO: PRE-FLIGHT INTERVIEW WITH GREG JOHNSON PLAY
VIDEO: PRE-FLIGHT INTERVIEW WITH MIKE FINCKE PLAY
VIDEO: PRE-FLIGHT INTERVIEW WITH ROBERTO VITTORI PLAY
VIDEO: PRE-FLIGHT INTERVIEW WITH DREW FEUSTEL PLAY
VIDEO: PRE-FLIGHT INTERVIEW WITH GREG CHAMITOFF PLAY

VIDEO: ENDEAVOUR CLEARED FOR APRIL 29 LAUNCH PLAY

VIDEO: EVACUATION DRESS REHEARSAL PLAY | HI-DEF
VIDEO: ASTRONAUTS BOARD ENDEAVOUR PLAY | HI-DEF
VIDEO: SUITING UP FOR PRACTICE COUNT PLAY | HI-DEF
VIDEO: SHUTTLE INSPECTED FOR STORM DAMAGE PLAY | HI-DEF
VIDEO: CREW TEST-DRIVES PAD ESCAPE VEHICLE PLAY | HI-DEF
VIDEO: ASTRONAUT CHAT AT THE PRESS SITE PLAY | HI-DEF
VIDEO: CREW ARRIVES FOR PRACTICE COUNT PLAY | HI-DEF

VIDEO: PAYLOADS ARRIVE AT LAUNCH PAD 39A PLAY | HI-DEF
VIDEO: CANISTER ROTATED UPRIGHT FOR PAD PLAY | HI-DEF
VIDEO: PALLET OF SPARE PARTS INTO CANISTER PLAY | HI-DEF
VIDEO: AMS PAYLOAD PUT INTO TRANSPORTER PLAY | HI-DEF

VIDEO: SHUTTLE AND STATION PROGRAM BRIEFING PLAY
VIDEO: THE STS-134 MISSION OVERVIEW PRESENTATIONS PLAY
VIDEO: IN-DEPTH WITH ALPHA MAGNETIC SPECTROMETER PLAY
VIDEO: PREVIEW BRIEFING ON MISSION'S SPACEWALKS PLAY
VIDEO: THE ASTRONAUTS' PRE-FLIGHT NEWS BRIEFING PLAY

VIDEO: SUN RISES OVER THE LAUNCH PAD PLAY | HI-DEF
VIDEO: ENDEAVOUR ARRIVES ATOP PAD 39A PLAY | HI-DEF
VIDEO: ROLLOUT FROM VEHICLE ASSEMBLY BUILDING PLAY | HI-DEF

VIDEO: HOISTING ENDEAVOUR TO TANK AND SRBS PLAY | HI-DEF
VIDEO: ORBITER GOES VERTICAL PLAY | HI-DEF
VIDEO: ENDEAVOUR LEAVES PROCESSING HANGAR PLAY | HI-DEF

VIDEO: PAYLOAD MEDIA DAY PLAY | HI-DEF
VIDEO: THE ALPHA MAGNETIC SPECTROMETER PLAY | HI-DEF
VIDEO: PAYLOAD REMOVED FROM C-5 PLAY | HI-DEF
VIDEO: AMS ARRIVES FROM EUROPE PLAY | HI-DEF

VIDEO: EXPRESS LOGISTICS CARRIER NO. 3 PLAY | HI-DEF
VIDEO: HIGH-PRESSURE OXYGEN GAS TANK PLAY | HI-DEF
VIDEO: PUTTING STATION ANTENNA ON CARRIER PLAY | HI-DEF

VIDEO: TANK UNLOADED TO ASSEMBLY BUILDING PLAY | HI-DEF
VIDEO: THE EXTERNAL FUEL TANK ARRIVES PLAY | HI-DEF
VIDEO: BOOSTER SEGMENT MOVED TO VAB PLAY | HI-DEF
VIDEO: KENNEDY SPACE CENTER SRB CEREMONY PLAY | HI-DEF
VIDEO: ENDEAVOUR FITTED WITH MAIN ENGINES PLAY | HI-DEF
VIDEO: ORBITER TOWED OFF RUNWAY PLAY | HI-DEF

MORE: STS-134 VIDEO ARCHIVE
HDTV: HIGH-DEFINITION COVERAGE
SUBSCRIBE NOW



MISSION STATUS CENTER