







Shuttle Discovery launch delayed to late February

BY WILLIAM HARWOOD

STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION

Posted: January 6, 2011



NASA managers Thursday decided to give engineers additional time to assess external tank cracks and repair scenarios, ruling out an early February launch for the shuttle Discovery. The next shuttle launch window opens Feb. 27, but NASA is assessing whether it might be possible to move that up a few days.

Credit: NASA



Additional meetings are planned next week to review progress with already-ordered crack repairs, potential work to beef up other structural ribs, or stringers, in the external tank and the results of an on-going analysis into the root cause of the eight cracks discovered to date. A new target launch date is expected after a program requirements control board meeting Jan. 13 at the Johnson Space Center in Houston. The next shuttle launch window, the one NASA managers ruled out Thursday, opens Feb. 3 and closes Feb. 10. The next window after that opens Feb. 27 and closes March 6. The opening of the late-February window is based on plans by the European Space Agency to launch an unmanned cargo ship Feb. 15 to deliver critical supplies to the International Space Station. The normal flight plan calls for ESA's Automated Transfer Vehicle to dock with the lab complex on Feb. 26, clearing the way for Discovery to take off the next day. If the ATV rendezvous profile can be compressed, it may be possible to launch Discovery a few days ahead of Feb. 27. But as of this writing, it's not yet clear whether that's a viable scenario. NASA had hoped to launch Discovery on Nov. 1. But the flight was delayed by unrelated technical problems and finally, on Nov. 5, by a gaseous hydrogen leak in a 7-inch vent line quick-disconnect fitting on the side of the external tank. During work to drain the tank, engineers spotted cracks in its foam insulation near the top of the intertank compartment that separates the tank's hydrogen and oxygen sections. When the damaged foam was removed, four cracks were found in two adjacent stringers near the tank's left-side booster attachment thrust panel, which helps carry the load during launch. After an instrumented fueling test Dec. 17 to collect data on how exposure to ultra-low temperatures affects the intertank stringers, Discovery was moved back to the Vehicle Assembly Building for additional inspections. Four more small cracks on three stringers were found on the opposite side of the tank from the shuttle on Dec. 29. The four cracks discovered in the wake of the Nov. 5 launch scrub were repaired by splicing in pristine stringer segments and attaching doublers to provide additional strength. The same repair was ordered for the cracks discovered in the VAB. Because engineers have not been able to determine a root cause, NASA managers also ordered so-called radius block stiffeners attached to another 32 stringers to either side of the two booster attachment thrust panels. The intertank is built with 108 stringers and NASA managers are considering whether to install radius blocks all the way around the circumference of the external tank to ensure an adequate safety margin. While a single root cause of the cracks has not been determined, it appears the stringers in question were made using an aluminum alloy from a batch produced in 2002 that has a mottled appearance and may not be as strong as engineers expected. With the addition of the radius block modification, testing indicates the tank's structural safety margin will be more than adequate. But engineers need to make sure the modifications have no unintended consequences and the analysis is not yet complete.



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Additional coverage for subscribers:

VIDEO: WORK UNDERWAY TO REMOVE FOAM AND SENSORS PLAY | HI-DEF

VIDEO: SETTING UP ACCESS PLATFORMS AROUND TANK PLAY | HI-DEF



VIDEO: SHUTTLE ROLLED BACK TO ASSEMBLY BUILDING PLAY | HI-DEF

VIDEO: DISCOVERY DEPARTS LAUNCH PAD 39A PLAY | HI-DEF

VIDEO: LUNAR ECLIPSE OVER DISCOVERY PLAY | HI-DEF



VIDEO: HIGHLIGHTS FROM THE FUELING TEST PLAY | HI-DEF

VIDEO: RECAP OF THE FUELING EXERCISE PLAY

VIDEO: FUELING TEST COUNTDOWN UPDATE PLAY

VIDEO: COMMENTS FROM SHUTTLE LAUNCH DIRECTOR PLAY

VIDEO: GROUND UMBILICAL CARRIER PLATE CHECKED PLAY

VIDEO: INFO ON EXTERNAL TANK INSTRUMENTATION PLAY

VIDEO: DETAILED INFORMATION ON SPECIAL FUELING TEST PLAY



VIDEO: SHUTTLE DISCOVERY'S LAUNCH DELAYED TO FEBRUARY PLAY



VIDEO: FINAL PREPS FOR INSTRUMENTED TEST PLAY | HI-DEF

VIDEO: STRAIN GAUGES ATTACHED TO TANK PLAY | HI-DEF

VIDEO: BACKSCATTER INSPECTIONS OF TANK MIDSECTION PLAY | HI-DEF



VIDEO: INSTALLING DOUBLERS OVER STRINGERS PLAY | HI-DEF

VIDEO: GASEOUS HYDROGEN VENT ARM RETURNED PLAY | HI-DEF

VIDEO: DOUBLERS TO BEEF UP CRACKED BEAMS PLAY | HI-DEF

VIDEO: HYDROGEN FITTING IS REINSTALLED PLAY | HI-DEF

VIDEO: OPENING UP TANK'S ENTRANCE DOOR PLAY | HI-DEF

VIDEO: GUCP DETACHED AND SEALS REMOVED PLAY | HI-DEF

VIDEO: BROKEN FOAM REMOVED FROM THE TANK PLAY | HI-DEF

VIDEO: VENT ARM LETS GO FROM LEAKY GUCP PLAY | HI-DEF

VIDEO: DISCOVERY AWAITS REPAIRS TO TANK PROBLEMS PLAY | HI-DEF



VIDEO: INFORMATIVE DESCRIPTION OF TANK CRACK PROBLEM PLAY

VIDEO: DISCOVERY'S LAUNCH DELAYED TO MID-DECEMBER PLAY



VIDEO: GASEOUS HYDROGEN VENT ARM DETACHED FROM SHUTTLE PLAY



VIDEO: STS-133 MISSION PREVIEW MOVIE PLAY | HI-DEF

VIDEO: SHUTTLE DISCOVERY CREW BIOGRAPHIES PLAY | HI-DEF

VIDEO: ISS EXPEDITION 25-26 PREVIEW MOVIE PLAY | HI-DEF

VIDEO: SPACE STATION CREW BIOGRAPHIES PLAY | HI-DEF



VIDEO: POST-SCRUB NEWS BRIEFING ON LEAK PLAY

VIDEO: GASEOUS HYDROGEN LEAK SCRUBS LAUNCH PLAY | HI-DEF

VIDEO: BAD WEATHER DELAYS DISCOVERY LAUNCH PLAY

VIDEO: ELECTRICAL ISSUE NO LONGER A CONCERN FOR DISCOVERY PLAY

VIDEO: LAUNCH POSTPONED BY ELECTRICAL CONCERN PLAY

VIDEO: TUESDAY MORNING'S COUNTDOWN STATUS CHECK PLAY

VIDEO: DISCOVERY'S PRE-LAUNCH NEWS CONFERENCE PLAY

VIDEO: COUNTDOWN PREVIEW BRIEFING AND WEATHER FORECAST PLAY

VIDEO: ANOTHER 24-HOUR DELAY ORDERED TO FINISH REPAIRS PLAY

VIDEO: LAUNCH DELAYED 24 HOURS BY LEAK REPAIRS PLAY



VIDEO: ASTRONAUTS ARRIVE FOR LAUNCH PLAY | HI-DEF



VIDEO: FLIGHT READINESS REVIEW SETS LAUNCH DATE PLAY



VIDEO: SHUTTLE AND STATION PROGRAM BRIEFING PLAY

VIDEO: THE STS-133 MISSION OVERVIEW PRESENTATIONS PLAY

VIDEO: PREVIEW BRIEFING ON MISSION'S SPACEWALKS PLAY

VIDEO: IN-DEPTH BACKGROUND ON ROBONAUT 2 HUMANOID PLAY

VIDEO: THE ASTRONAUTS' PRE-FLIGHT NEWS BRIEFING PLAY



VIDEO: PAYLOAD BAY DOORS CLOSED FOR LAUNCH PLAY | HI-DEF

VIDEO: CREW LEAVES KSC FOR TRIP TO HOUSTON PLAY | HI-DEF

VIDEO: ASTRONAUTS INSPECT THE PAYLOAD BAY PLAY | HI-DEF

VIDEO: SHUTTLE EVACUATION PRACTICE PLAY | HI-DEF

VIDEO: ASTRONAUTS EGRESS SHUTTLE AS SEEN LIVE PLAY

VIDEO: ASTRONAUTS BOARD DISCOVERY PLAY | HI-DEF

VIDEO: SUN RISES ON LAUNCH PAD 39A PLAY | HI-DEF

VIDEO: LAUNCH DAY REHEARSAL BEGINS PLAY | HI-DEF

VIDEO: COMMEMORATIVE WALL SIGNING IN VAB PLAY | HI-DEF

VIDEO: CREW BRIEFED ON EMERGENCY PROCEDURES PLAY | HI-DEF

VIDEO: IN SHUTTLE TRAINING AIRCRAFT'S COCKPIT PLAY | HI-DEF

VIDEO: TEST-DRIVING AN EMERGENCY ARMORED TANK PLAY | HI-DEF



VIDEO: PRE-LAUNCH INTERVIEW WITH STEVE LINDSEY PLAY

VIDEO: PRE-LAUNCH INTERVIEW WITH ERIC BOE PLAY

VIDEO: PRE-LAUNCH INTERVIEW WITH AL DREW PLAY

VIDEO: PRE-LAUNCH INTERVIEW WITH TIM KOPRA PLAY

VIDEO: PRE-LAUNCH INTERVIEW WITH MIKE BARRATT PLAY

VIDEO: PRE-LAUNCH INTERVIEW WITH NICOLE STOTT PLAY



VIDEO: PAYLOADS INSTALLED INTO DISCOVERY PLAY | HI-DEF

VIDEO: MISSION PAYLOADS ARRIVE AT LAUNCH PAD PLAY | HI-DEF

VIDEO: CANISTER HAULING PAYLOADS TURNED UPRIGHT PLAY | HI-DEF

VIDEO: MODULE HOISTED INTO SHIPPING CANISTER PLAY | HI-DEF

VIDEO: WEIGHING NEW SPACE STATION MODULE PLAY | HI-DEF



VIDEO: GANTRY PLACED AROUND DISCOVERY PLAY | HI-DEF

VIDEO: SHUTTLE ATLANTIS REACHES PAD 39A PLAY | HI-DEF

VIDEO: CROWDS WATCH DISCOVERY'S FINAL ROLLOUT PLAY | HI-DEF



VIDEO: SHUTTLE HOISTED FOR ATTACHMENT TO TANK PLAY | HI-DEF

VIDEO: CRANE ROTATES THE ORBITER VERTICALLY PLAY | HI-DEF

VIDEO: DISCOVERY DEPARTS ITS HANGAR PLAY | HI-DEF



VIDEO: TIME-LAPSE SHOWS DISCOVERY ASCENDING IN VAB PLAY

VIDEO: TIME-LAPSE SHOWS THE MOVE TO ASSEMBLY BUILDING PLAY



VIDEO: DISCOVERY'S MAIDEN FLIGHT: FIRST TRIP TO VAB PLAY

VIDEO: DISCOVERY'S MAIDEN FLIGHT: ROLLOUT TO PAD 39A PLAY

VIDEO: DISCOVERY'S MAIDEN FLIGHT: TEST-FIRING ENGINES PLAY

VIDEO: DISCOVERY'S MAIDEN FLIGHT: ASSORTED VIEWS OF FRF PLAY



VIDEO: THE HISTORY OF SHUTTLE DISCOVERY PLAY

VIDEO: THE HISTORY OF SHUTTLE ENDEAVOUR PLAY

VIDEO: THE HISTORY OF SHUTTLE ATLANTIS PLAY



VIDEO: INSPECTION OF THE MISSION PAYLOADS PLAY | HI-DEF

VIDEO: ROBONAUT ARRIVES AT KENNEDY SPACE CENTER PLAY | HI-DEF

VIDEO: SPACE STATION'S SPARE THERMAL RADIATOR PLAY | HI-DEF

VIDEO: BLANKETING LEONARDO WITH INSULATION PLAY | HI-DEF

VIDEO: RACK INSERTED INTO LEONARDO FOR LAUNCH PLAY | HI-DEF

VIDEO: LEONARDO RETURNS FROM ITS PREVIOUS FLIGHT PLAY | HI-DEF

VIDEO: STATION'S SPARE PARTS DEPOT ARRIVES PLAY | HI-DEF



VIDEO: ORBITER'S PAYLOAD BAY CLOSED FOR ROLLOUT PLAY | HI-DEF

VIDEO: ASTRONAUTS VISIT THEIR SPACECRAFT PLAY | HI-DEF

VIDEO: CREW INSPECTS LEONARDO MODULE PLAY | HI-DEF

VIDEO: DISCOVERY RECEIVES ITS MAIN ENGINES PLAY | HI-DEF

VIDEO: FUEL TANK MATED TO SOLID ROCKET BOOSTERS PLAY | HI-DEF

VIDEO: HOISTING FUEL TANK INTO CHECKOUT BAY PLAY | HI-DEF

VIDEO: EXTERNAL FUEL TANK UNLOADED FROM BARGE PLAY | HI-DEF

VIDEO: MISSION'S FUEL TANK ARRIVES AT SPACEPORT PLAY | HI-DEF



VIDEO: POST-FLIGHT DESERVICING: OMS POD PLAY | HI-DEF

VIDEO: POST-FLIGHT DESERVICING: OBSS BOOM PLAY | HI-DEF

VIDEO: POST-FLIGHT DESERVICING: ENGINES PLAY | HI-DEF

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